Method for manufacturing wet friction plate

Abstract

The present application provides a manufacturing method of a wet friction plate, which can improve the retention of lubricating oil in a fine groove formed by laser. The manufacturing method of the wet friction plate (200) is to manufacture a friction member (210) by papermaking processing in a first process, and then form a fine groove (211) on the friction member (210) in a second process. The friction member (210) is manufactured in a state that the internal heat-hardening resin is semi-hardened. The fine groove (211) is formed by laser into a V-shaped cross-sectional shape. Next, in a third process, the friction member (210) is arranged on a core plate (201) by an adhesive composed of heat-hardening resin. Next, in a fourth process, the friction member (210) is heated and pressed, so as to crush the fine groove (211) and form a concave-convex on the groove inner surface (212), and make the heat-hardening resin completely hardened.

Description

Technical Field

[0001] This invention relates to a method for manufacturing wet friction plates used in lubricating oils. Background Technology

[0002] Traditionally, wet multi-plate clutches have been installed on both sides of four-wheeled vehicles or two-wheeled motor vehicles to transmit or disconnect the rotational driving force of the prime mover, such as the engine, from the driven body, such as the wheels. Generally, a wet multi-plate clutch transmits or disconnects rotational driving force by pressing two facing plates against each other in lubricating oil.

[0003] At this point, one of the two plates is a wet friction plate formed by circumferentially arranged friction elements on the surface of a flat, annular core plate. For example, Patent Document 1 discloses a laser processing method and a laser processing apparatus for friction plates (hereinafter referred to as "wet friction plates"), wherein the friction plate is formed by laser processing of a recess (hereinafter referred to as "fine groove") consisting of tiny bumps or grooves on the surface of the friction element. Thus, the wet friction plate uses laser processing to make the processed ends in the fine grooves sharper, thereby promoting the flow of lubricating oil in the fine grooves compared to conventional cutting processes.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2014-133242

[0007] However, although the laser processing method and laser processing apparatus for wet friction plates described in the aforementioned patent document 1 promotes the flow of lubricating oil, on the other hand, the lubricating oil retention is low, resulting in a decrease in the cooling performance of the wet friction plates with lubricating oil.

[0008] This invention was developed to solve the above-mentioned problems and aims to provide a method for manufacturing wet friction plates that can improve the retention of lubricating oil in fine grooves formed by laser. Summary of the Invention

[0009] To achieve the above objectives, the present invention is characterized by a method for manufacturing a wet friction pad, wherein the wet friction pad is formed by arranging friction elements along the circumferential direction on the surface of a core plate formed in the shape of a flat ring, and the method for manufacturing the wet friction pad includes: a groove forming step in which a laser is irradiated relative to the friction element while being relatively displaced, thereby forming a concave groove on the surface of the friction element; and a crushing step in which the friction element is pressed to crush and deform the groove.

[0010] According to the features of the present invention configured as described above, in the method for manufacturing a wet friction pad, after forming fine grooves using a laser, a friction element with these grooves is pressed to crush the grooves, thereby making the surface inside the grooves uneven, thus improving the retention of lubricating oil. In this case, the grooves have a width of 10 μm to 1000 μm and a depth of 10 μm to 1000 μm, and the cross-sectional shape is formed as a partially intermittently or continuously elongated strip with concave sections. In this case, in addition to paper materials made of fibrous aggregates, rubber materials or cork materials can also be used as the friction element.

[0011] Furthermore, another feature of the present invention is that the method for manufacturing the wet friction pad further includes a friction element arrangement step of arranging friction elements on a core plate, wherein the groove forming step is performed before the friction element arrangement step.

[0012] According to other features of the present invention configured in this way, the method of manufacturing wet friction pads involves performing a groove forming process before the friction element assembly process. Therefore, compared to the case where grooves are machined on the friction element on the core plate, it is possible to easily form high-precision grooves.

[0013] Furthermore, another feature of the present invention is that in the method for manufacturing the wet friction pad, the crushing step is performed on the friction element disposed on the core plate.

[0014] According to other features of the present invention configured as such, in the method for manufacturing wet friction pads, the crushing process is performed on the friction element disposed on the core plate. Therefore, compared to the case where the crushing process is performed outside the core plate, it can also serve as the bonding process of the friction element to the core plate, thereby reducing the workload and manufacturing wet friction pads more efficiently.

[0015] Furthermore, another feature of the present invention is that the method for manufacturing the wet friction pad further includes a friction element arrangement step of arranging friction elements on a core plate, a groove forming step performed on the friction elements arranged on the core plate, and a crushing step performed on the friction elements arranged on the core plate.

[0016] According to other features of the present invention configured as such, in the method for manufacturing wet friction pads, the groove forming step and the crushing step are performed on the friction element disposed on the core plate, thus enabling the groove to be formed with high precision at the correct position on the core plate.

[0017] Furthermore, another feature of the present invention is that the method for manufacturing the wet friction pad further includes a friction element manufacturing step in which a papermaking body is used as a friction element and is manufactured. The papermaking body is an aggregate in which thermosetting resin is impregnated with numerous fibers. The crushing step involves heating and pressing the friction element simultaneously.

[0018] According to other features of the present invention configured as such, in the method of manufacturing a wet friction pad, a friction element composed of a papermaking body made of an aggregate of numerous fibers impregnated with thermosetting resin is heated and pressed, thereby suppressing the rebound of the pressed friction element and crushing the fine grooves with high precision, thereby manufacturing a wet friction pad.

[0019] Furthermore, another feature of the present invention is that in the method for manufacturing the wet friction pad, the friction element manufacturing step is to manufacture the paper body in a semi-cured state where the thermosetting resin is cured in a range that is not fully cured, and the crushing step is to heat the friction element so that the thermosetting resin in the semi-cured state is fully cured.

[0020] According to other features of the present invention configured as described above, in the method for manufacturing a wet friction pad, the friction element is heated during the crushing process, thereby completely curing the semi-cured thermosetting resin. This suppresses the rebound of the pressed friction element and precisely crushes the fine grooves, thus manufacturing a wet friction pad. Furthermore, in this method for manufacturing a wet friction pad, the thermosetting resin is in a semi-cured state, therefore, compared to pressing a friction element where the thermosetting resin is fully cured, the pressure applied to the friction element can be reduced.

[0021] In addition, another feature of the present invention is that in the manufacturing method of the wet friction pad, the friction element configuration step is to place an adhesive between the core plate and the friction element, and the crushing step is to press the friction element so that the friction element is adhered to the core plate.

[0022] According to other features of the present invention configured as such, in the method of manufacturing wet friction pads, an adhesive is disposed between the core plate and the friction element and the friction element is pressed to adhere the friction element to the core plate. Therefore, the crushing of the fine groove and the adhesion of the friction element can be performed simultaneously, which can improve work efficiency. Attached Figure Description

[0023] Figure 1 This is a cross-sectional view showing the overall structure of a wet multi-plate clutch device equipped with the wet friction plates of the present invention.

[0024] Figure 2 It indicates assembly at Figure 1 A schematic top view of the external structure of the wet friction plate of the present invention within the wet multi-plate clutch device shown.

[0025] Figure 3 It means Figure 2 A partially enlarged cross-sectional view of the structure of the fine grooves formed in the friction element in the wet friction plate shown.

[0026] Figure 4 This is a flowchart illustrating the manufacturing process of the wet friction pad of the present invention.

[0027] Figure 5 It is a schematic representation of Figure 4 A schematic side view of the structure of the laser processing equipment used in the groove forming process of the manufacturing process of the wet friction pad shown.

[0028] Figure 6 It means through Figure 5 The diagram shows a top view of a long, narrow friction element with grooves formed by a laser processing device.

[0029] Figure 7 It means through Figure 5 A partially enlarged cross-sectional view of the structure of the groove formed by the laser processing device shown.

[0030] Figure 8 It is a schematic representation Figure 4 A schematic side view of the structure of the hot stamping apparatus used in the crushing process of the fine groove in the manufacturing process of the wet friction plate shown. Detailed Implementation

[0031] The following describes one embodiment of the manufacturing method of the wet friction pad of the present invention with reference to the drawings. Figure 1 This is a schematic cross-sectional view showing the overall structure of a wet multi-plate clutch device 100 equipped with the wet friction plate 200 of the present invention. Furthermore, Figure 2 It means Figure 1 This is a schematic top view of the external structure of the wet friction plate 200 of the present invention, which is included in the wet multi-plate clutch device 100 shown. Furthermore, in the figures referenced in this specification, some constituent elements are shown in an exaggerated or schematic manner for ease of understanding of the present invention. Therefore, the dimensions or ratios between the constituent elements may sometimes differ.

[0032] The wet multi-plate clutch device 100 is a mechanical device that transmits the driving force of the prime mover, i.e., the engine (not shown), in a two-wheeled motor vehicle (motorcycle) to the driven body, i.e., the wheel (not shown), or disconnects it, and is disposed between the engine and the transmission (gearbox) (not shown).

[0033] (Structure of wet multi-plate clutch device 100)

[0034] The wet multi-plate clutch device 100 includes an aluminum alloy housing 101. The housing 101 is formed as a bottomed cylinder and is a component constituting part of the frame of the wet multi-plate clutch device 100. In the illustrated left side of the housing 101, the input gear 102 is fixed via a torque damper 102a and by a rivet 102b. The input gear 102 meshes with a drive gear (not shown) that is driven to rotate by an engine, thereby achieving rotational drive. In the inner circumferential surface of the housing 101, multiple clutch plates 103 (eight plates in this embodiment) are displaceable along the axial direction of the housing 101 and are held in a state where they can rotate integrally with the housing 101, respectively, by spline engagement.

[0035] The clutch plate 103 is a flat, annular part pressed against the wet friction plate 200 (described later). It is formed by punching a thin sheet of SPCC (cold-rolled steel sheet) into a ring shape. Each clutch plate 103 has oil grooves (not shown) formed on both sides (front and back) to retain the lubricating oil (described later) to a depth of several μm to tens of μm. Furthermore, each side (front and back) of the clutch plate 103 with the oil grooves undergoes surface hardening treatment to improve wear resistance. However, this surface hardening treatment is not directly related to the present invention and is therefore omitted from description.

[0036] Inside the housing 101, a slightly cylindrical friction plate support 104 is concentrically arranged with the housing 101. Multiple spline grooves are formed along the axial direction of the friction plate support 104 on its inner circumferential surface, and a shaft 105 splines into these spline grooves. The shaft 105 is a hollow shaft, and one end (right side of the diagram) rotatably supports the input gear 102 and the housing 101 via a needle roller bearing 105a, and the spline-fitted friction plate support 104 is fixedly supported by a nut 105b. That is, the friction plate support 104 and the shaft 105 rotate together integrally. On the other hand, the other end (left side of the diagram) of the shaft 105 is connected to a transmission (not shown) in a two-wheeled motor vehicle.

[0037] In the hollow portion of the axle 105, a shaft-shaped push rod 106 is disposed with its protrusion extending from one end (right side of the diagram) of the axle 105. The push rod 106, on the opposite side (left side of the diagram) of the protruding end from one end of the axle 105, is connected to a clutch operating lever (not shown) in a two-wheeled motor vehicle. Operation of the clutch operating lever causes the axle 105 to slide within its hollow portion along its axial direction.

[0038] On the outer peripheral surface of the friction plate support 104, multiple wet friction plates 200 (7 in this embodiment) can be displaced along the axial direction of the friction plate support 104 while clamping the clutch plate 103, and are held by spline engagement while being able to rotate integrally with the friction plate support 104.

[0039] On the other hand, the interior of the friction plate support 104 is filled with a predetermined amount of lubricating oil (not shown), and three cylindrical support columns 104a are formed thereon (only one is shown in the figure). The lubricating oil is supplied between the wet friction plate 200 and the clutch plate 103, and absorbs the frictional heat generated between the wet friction plate 200 and the clutch plate 103 or prevents the wear of the friction element 210.

[0040] Furthermore, the three cylindrical support columns 104a are formed with their protrusions outward (to the right of the diagram) in the axial direction towards the friction plate support 104. The push-cap 107, positioned concentrically with the friction plate support 104, is assembled using bolts 108a, a support plate 108b, and a compression spring 108c. The push-cap 107 is formed as a slightly circular plate with an outer diameter roughly the same as that of the wet friction plate 200, and is pressed against the friction plate support 104 by the compression spring 108c. Additionally, a release bearing 107a is provided in the inner center of the push-cap 107, facing the front end of the push rod 106 (to the right of the diagram).

[0041] (Structure of wet friction plate 200)

[0042] Details of wet friction plate 200 are as follows Figure 2 As shown, the core plate 201 is constructed by having an oil groove 203 and a friction element 210 respectively on a flat annular core plate 201. The core plate 201 is a component that serves as the base of the wet friction plate 200, and is formed by punching a thin sheet of SPCC (cold-rolled steel sheet) into a slightly annular shape. At this time, the inner periphery of the core plate 201 forms internally threaded splines 202 for engaging with the splines of the friction plate support 104.

[0043] In this wet friction plate 200, on the side facing the clutch plate 103, that is, in the annular plate surface of the core plate 201 facing the clutch plate 103, multiple (32 in this embodiment) small plate-shaped friction elements 210 are respectively provided along the circumferential direction of the core plate 201 with gaps forming oil grooves 203.

[0044] The oil groove 203 is a flow path for guiding lubricating oil between the inner and outer peripheries of the core plate 201 of the wet friction plate 200. It also serves as an oil retention portion to ensure that lubricating oil is present beforehand between the wet friction plate 200 and the clutch plate 103. It is formed by the gap between adjacent friction elements 210. In this embodiment, the oil groove 203 is formed by a fan-shaped portion between each group of four small, sheet-like friction elements 210 and a portion extending linearly between each of the four friction elements 210 disposed between two fan-shaped oil grooves 203. Furthermore, the shape and number of oil grooves 203 are appropriately set according to the specifications of the wet friction plate 200.

[0045] The friction element 210, which increases the frictional force relative to the clutch plate 103, is constructed by attaching small pieces of paper along the circumferential direction of the core plate 201. More specifically, the friction element 210 is constructed by impregnating the paper body with a thermosetting resin and then hardening it.

[0046] Here, the papermaking body is formed by adding filler to an aggregate of at least one type of organic and inorganic fibers. The organic fibers can be one or more of wood pulp, synthetic pulp, polyester fibers, polyamide fibers, polyimide fibers, polyvinyl alcohol modified fibers, polyvinyl chloride fibers, polypropylene fibers, polybenzimidazole fibers, acrylic fibers, carbon fibers, phenolic fibers, nylon fibers, and cellulose fibers. Furthermore, the inorganic fibers can be one or more of glass fibers, rock wool, potassium titanate fibers, ceramic fibers, silica fibers, silica-alumina fibers, kaolin fibers, bauxite fibers, kyanite fibers, boron fibers, magnesium oxide fibers, and metal fibers.

[0047] Furthermore, fillers function as friction modifiers and / or solid lubricants, and can be composed of one or more of the following: barium sulfate, calcium carbonate, magnesium carbonate, silicon carbide, boron carbide, titanium carbide, silicon nitride, boron nitride, alumina, silicon dioxide, zirconium dioxide, cashew nut shell powder, rubber powder, diatomaceous earth, graphite, talc, kaolin, magnesium oxide, molybdenum disulfide, nitrile rubber, acrylonitrile / butadiene rubber, styrene-butadiene rubber, silicone rubber, and fluororubber. Additionally, thermosetting resins include phenolic resins, melamine resins, epoxy resins, urea resins, and silicone resins.

[0048] The friction element 210 has a thickness of 0.3 mm or more and 0.6 mm or less, and is adhered to the core plate 201 by an adhesive (not shown). In this embodiment, the friction element 210 is formed by arranging four small quadrilateral pieces extending along the circumferential direction of the core plate 201, separated by three linear oil grooves 203, to form a small piece group. Eight such small piece groups are arranged in the circumferential direction of the core plate 201, separated by eight fan-shaped oil grooves 203. Furthermore, the shape and number of the friction element 210 are appropriately set according to the specifications of the wet friction plate 200 and are not limited to this embodiment.

[0049] Fine grooves 211 are formed on the surface of the friction element 210. These fine grooves 211 are used to regulate the retention and discharge of lubricating oil on the friction element 210, and are formed as concave grooves on the surface of the friction element 210. More specifically, as... Figure 3 As shown, the groove 211 is formed as an opening on the surface of the friction member 210 and a concave recess on the inner side. At this time, the inner surface 212 of the groove forming the groove 211 is composed of an irregular uneven surface.

[0050] In this embodiment, the two side surfaces 212a and 212b of the groove 211 are formed as inclined surfaces extending toward the interior of the friction member 210 and approaching each other, and the cross-sectional shape is formed as a slightly V-shaped (triangular). At this time, the groove 211 in this embodiment is formed with a groove width of about 100 μm and a depth of about 200 μm for the deepest recess.

[0051] The groove 211 is formed on the friction element 210 in the shape of an arc that extends continuously along the circumferential direction of the core plate 201. In this embodiment, the groove 211 is formed by three arcs arranged radially to the wet friction plate 200. At this time, the three arcs are formed by concentric circles centered on the center of the core plate 201.

[0052] (Manufacturing of wet friction plate 200)

[0053] Next reference Figure 4 The manufacturing method of the wet friction plate 200 with this configuration is explained. First, the operator manufactures the friction element 210 (friction element manufacturing process) as the first step. Specifically, the manufacturing process of the friction element 210 mainly consists of a paper-making process and a hardening process.

[0054] The papermaking process involves filtering fibers dispersed in a liquid to form long, thin sheets of paper, a method already known. Specifically, the papermaking process involves adding the raw materials for the papermaking body—that is, the organic fibers and / or the inorganic fibers, fillers, and coagulants—to water, stirring, filtering these materials from the resulting slurry into long, thin sheets, drying them, and obtaining the long, thin sheets of paper. At this point, the paper is dried to a moisture content of less than 10%.

[0055] Next, the curing process involves impregnating the paper body with a thermosetting resin and causing it to harden. Specifically, the operator either distributes a thermosetting resin solution (phenolic resin solution) onto the paper body or immerses the paper body in the thermosetting resin solution to impregnate it. Then, the solution is heated using a heater or heated rollers to harden it. At this point, the operator hardens the thermosetting resin solution to a semi-cured state, within the range where it has solidified but is not fully hardened. Thus, the operator obtains a friction element 210 composed of a paper body in a semi-cured state of thermosetting resin solution.

[0056] Next, as the second step, the operator forms a groove 211 on the friction element 210 (groove forming step). At this time, the operator uses a laser processing device 300 to form the groove 211. Here, the laser processing device 300 is a mechanical device that irradiates the friction element 210 with a laser L to form the groove 211.

[0057] like Figure 5 As shown, this laser processing apparatus 300 mainly comprises a laser oscillator (not shown), a laser adjustment optical system (not shown), a laser head 301, a worktable 302, a workpiece conveying mechanism 303, and a control device (not shown). The laser oscillator is a mechanical device that emits a laser L to form fine grooves 211 on the friction component 210. In this embodiment, the laser oscillator is an oscillator that oscillates a short-pulse laser with a frequency of 300 kHz, an output of 60 W, and a pulse width of nanoseconds, picoseconds, or femtoseconds. The laser adjustment optical system is composed of various optical components such as lenses and mirrors, as well as optical fibers, that guide the laser L emitted by the laser oscillator to the laser head 301 while correcting various aspects such as beam diameter, beam shape, and aberrations.

[0058] The laser head 301 is an optical device that directs the guided laser L towards the stage 302 from the laser adjustment optics system and focuses it onto the wet friction plate. This laser head 301 is configured to be displaceable relative to the stage 302 in three orthogonal directions: the X-axis, Y-axis, and Z-axis. Furthermore, the laser oscillator, the laser adjustment optics system, and the laser head 301 themselves are known mechanical devices.

[0059] The worktable 302 is a table that supports the friction member 210 from below, facing the laser head 301, and is made of metal material formed into a flat plate. The workpiece conveying mechanism 303 is a mechanical device used to convey the long strip-shaped friction member 210 from one side to the other along its long side, and is mainly composed of a pair of drive rollers that clamp the friction member 210.

[0060] The control device is a microcomputer composed of CPU, ROM, RAM, etc., which comprehensively controls the operation of the laser processing device 300. Specifically, the control device controls the operation of the laser oscillator, laser adjustment optical system, laser head 301 and workpiece conveying mechanism 303 according to the operator's instructions, arranges the friction member 210 on the worktable 302, and while irradiating the friction member 210 on the worktable 302 with laser L, it moves the laser head 301 to form a groove 211.

[0061] In the second step, the operator pulls out the friction element 210 wound into a roller shape, clamps the end of the pulled-out friction element 210 into the workpiece conveying mechanism 303, and instructs the control device of the laser processing apparatus 300 to process the groove 211. Responding to the instruction, the control device controls the operation of the workpiece conveying mechanism 303, intermittently conveying the friction element 210, thereby intermittently positioning the friction element 210 on the worktable 302. Next, the control device causes the laser L to be emitted from the laser head 301 onto the friction element 210 positioned on the worktable 302, while simultaneously displacing the laser head 301 in the X-axis and Y-axis directions, thereby displacing the laser L on the friction element 210 and forming the groove 211.

[0062] In this embodiment, such as Figure 6 As shown, the laser processing apparatus 300 forms three fine grooves 211 on each of the four friction members 210 disposed between the two fan-shaped oil grooves 203, and the three fine grooves 211 are continuously connected along the width direction of the friction member 210. At this time, as... Figure 7 As shown, each groove 211 is formed with a V-shaped (triangular) cross-sectional shape. Then, the side surfaces 212a and 212b constituting each groove 211 are formed as flat planes with few irregularities. Furthermore, each groove 211 is formed to a depth greater than the depth of the final formed groove 211. In addition, Figure 6 In the diagram, the friction element 210 relative to the groove 211 is hypothetically represented by a chain line connecting two points. Furthermore, Figure 5 and Figure 6 In the diagram, the conveying direction of the elongated friction element 210 is indicated by a dashed arrow.

[0063] Next, as the third step, the operator prepares the core plate 201 and arranges friction elements 210 on both surfaces of the core plate 201 (friction element arrangement step). Here, the core plate 201 is formed into a ring shape with splines 202 by another stamping process. This stamping process is a conventional method, so its description is omitted.

[0064] The operator applies a liquid adhesive to the entire surface of the core plate 201 using a brush or roller, and then places the friction element 210 on the adhesive. Here, a liquid thermosetting resin is used as the adhesive. Alternatively, the operator can cut the strip-shaped friction element 210 while it is placed on the core plate 201 to form small pieces of friction element 210, or place the pre-cut small pieces of friction element 210 onto the core plate 201 relative to the strip-shaped friction element 210. The method of placing these friction elements 210 on the core plate 201 is known technology.

[0065] The friction element 210 disposed on the core plate 201 is temporarily fixed to the core plate 201 by the adhesive force of the uncured adhesive. Therefore, the operator can place the friction element 210 on both sides by flipping the core plate 201. Furthermore, in this third step, the operator may apply the adhesive only to the location where the friction element 210 is disposed, or may apply the adhesive only in a circular pattern along the circumference of the friction element 210. Alternatively, the operator may apply the adhesive to the friction element 210 itself.

[0066] Next, as the fourth step, the operator crushes the groove 211 (crushing process). This crushing process also serves as the bonding process of the friction element 210 to the core plate 201, and is performed using a hot stamping apparatus 400. Here, the hot stamping apparatus 400 is a mechanical device used to crush the groove 211 and bond the friction element 210 to the core plate 201 while heating the friction element 210. This hot stamping apparatus 400 is a known mechanical device, so detailed description is omitted, but its structure is briefly described.

[0067] like Figure 8As shown, this hot stamping processing apparatus 400 mainly comprises a lower pressure plate 401, an upper pressure plate 402, a movable support device 403, and a control device. The lower pressure plate 401 is a part that holds the core plate 201 and works in conjunction with the upper pressure plate 402 to clamp, heat, and press the core plate 201. It is formed by forming metal material into a plate shape. At this time, a heater (not shown) is provided inside the lower pressure plate 401, which is heated by electricity. The lower pressure plate 401 is fixed to the upper surface of the lower base 403a of the movable support device 403.

[0068] The upper pressure plate 402 is positioned above the lower pressure plate 401 and works in conjunction with the lower pressure plate 401 to clamp, heat, and press the core plate 201. It is constructed by forming a metal material into a plate shape. The upper pressure plate 402 contains a heater (not shown) that is heated by electricity. This upper pressure plate 402 is fixed to the bottom surface of the upper base plate 403c of the movable support device 403.

[0069] The movable support device 403 is a mechanical device (refer to the dashed arrow in the figure) capable of supporting the upper pressure plate 402 relative to the lower pressure plate 401 in a way that allows them to approach or separate. It comprises a lower base 403a, support columns 403b, and an upper base plate 403c. The lower base 403a is a flat metal plate that fixes and supports the lower pressure plate 401. The support columns 403b are parts that guide and support the upper base plate 403c in the direction that allows the upper pressure plate 402 to approach or separate from the lower pressure plate 401. They are composed of multiple metal rods that stand upright on the outer edge of the lower base 403a.

[0070] The upper base plate 403c is a flat metal plate that supports the upper pressure plate 402. Through holes are formed in the upper base plate 403c at positions corresponding to the support columns 403b on its outer edge, and the support columns 403b slide freely into these through holes. Furthermore, the upper base plate 403c is supported by a hydraulic drive device (not shown) that raises and lowers the upper base plate 403c by hydraulic pressure.

[0071] The control device is a microcomputer composed of CPU, ROM, RAM, etc., and comprehensively controls the operation of the hot stamping processing apparatus 400. Specifically, the control device controls the operation of each heater of the lower pressure plate 401 and the upper pressure plate 402 and the hydraulic drive device in the movable support device 403 according to the operator's instructions, and presses the core plate 201 while heating the lower pressure plate 401 and the upper pressure plate 402, thereby crushing the friction element 210 including the groove 211.

[0072] In the fourth step, after the operator places the core plate 201, to which the friction element 210 is temporarily fixed, onto the lower pressure plate 401, the operator instructs the control device of the hot stamping processing apparatus 400 to perform heating and pressing processing on the friction element 210. The control device responds to this instruction by controlling the operation of the heaters on the lower pressure plate 401 and the upper pressure plate 402, heating them to predetermined temperatures, and then controlling the operation of the hydraulic drive device to lower the upper pressure plate 402 toward the lower pressure plate 401 and press the entire core plate 201 (refer to the dotted arrow in the diagram).

[0073] Therefore, the core plate 201 is heated and pressed while being clamped by the lower pressure plate 401 and the upper pressure plate 402. At this time, although the temperature of the heated friction element 210, the applied pressure, and the time are appropriately set according to the specifications of the wet friction pad 200, it is necessary to at least apply pressure and time that compresses the friction element 210 in the thickness direction, and to achieve a temperature and time that allows the thermosetting resin to fully cure. Here, complete curing of the thermosetting resin means that the thermosetting resin has cured to a degree that is suitable for use in the wet friction pad 200.

[0074] Therefore, the semi-cured thermosetting resin contained inside the friction member 210 and the thermosetting resin coated between the core plate 201 and the friction member 210 are cured respectively. Thus, the friction member 210 is cured and adhered to the core plate 201 while being compressed in the thickness direction. At this time, the friction member 210 is adhered to the core plate 201 in a state where it is compressed to a thickness of more than 1 / 10 and less than 1 / 2 of its original thickness.

[0075] Also, such as Figure 3 As shown, the grooves 211 formed on the friction element 210 are crushed in the thickness direction of the friction element 210. Specifically, the depth of the grooves 211 is reduced, and the sharp shape at the bottom of the groove is deformed into a wider shape, while the sides 212a and 212b are uneven, and the cross-sectional shape is formed into a slightly V-shape that is crushed in the thickness direction of the friction element 210.

[0076] Then, the control device heats and presses the core plate 201 with the lower pressure plate 401 and upper pressure plate 402 for a predetermined time, and then controls the operation of the hydraulic drive device to raise the upper pressure plate 402 and separate it from the lower pressure plate 401, and stops the heating of each heater of the lower pressure plate 401 and upper pressure plate 402 (refer to the dashed arrows in the figure). Therefore, the operator can remove the core plate 201 with the friction element 210 attached, i.e., the wet friction plate 200, from the lower pressure plate 401. After this, although the operator performs friction characteristic adjustment and inspection procedures to complete the wet friction plate 200, these are not directly related to the present invention, so their description is omitted.

[0077] (Operation of wet friction plate 200)

[0078] The operation of the wet friction plate 200 constructed in the above manner will now be explained. This wet friction plate 200, as described, is assembled within a wet multi-plate clutch assembly 100. This wet multi-plate clutch assembly 100, as described, is located between the engine and transmission in a vehicle. The transmission and disengagement of the engine's driving force to the transmission are achieved by the vehicle operator operating the clutch operating lever.

[0079] That is, when the operator (not shown) operates the clutch operating lever (not shown) to retract the push rod 106 (moving it to the left in the diagram), the front end of the push rod 106 is not pressing against the release bearing 107a, and the pressure cover 107 presses against the clutch disc 103 by the elastic force of the compression spring 108c. As a result, the clutch disc 103 and the wet friction plate 200 move towards the flange-shaped pressure-bearing portion 104b formed on the outer peripheral surface of the friction plate support 104, and simultaneously push against each other, thus achieving a frictional connection. As a result, the engine driving force transmitted to the input gear 102 is transmitted to the transmission through the clutch disc 103, the wet friction plate 200, the friction plate support 104, and the shaft 105.

[0080] On the other hand, when the operators of both vehicles operate the clutch operating lever (not shown) to move the push rod 106 forward (moving to the right as shown), the front end of the push rod 106 presses against the release bearing 107a. Meanwhile, the pressure cover 107, resisting the elastic force of the compression spring 108c, moves to the right as shown, separating from the clutch disc 103. As a result, the clutch disc 103 and the wet friction plate 200 move towards the pressure cover 107, simultaneously pressing against each other, thus disengaging and separating. Consequently, the transmission of driving force from the clutch disc 103 to the wet friction plate 200 is interrupted, and the transmission of engine driving force to the input gear 102 is disconnected from the transmission.

[0081] In the clutch ON state, where the clutch disc 103 and the wet friction disc 200 are in frictional contact, a portion of the lubricating oil present on the friction element 210 enters the fine grooves 211 formed on the surface of the friction element 210. At this time, the surface area of ​​the inner surface 212 of the fine grooves 211 is increased by the unevenness, thereby increasing the penetration of lubricating oil into the internal structure of the friction element 210 and improving the cooling effect of the friction element 210.

[0082] Furthermore, in the clutch OFF state where the clutch plate 103 is separated from the wet friction plate 200, the groove 211 has an uneven surface formed on the inner surface 212 of the groove, thereby improving the retention of lubricating oil in the groove 211 and thus improving the cooling effect of the friction element 210.

[0083] Furthermore, even when the clutch plate 103 and the wet friction plate 200 are repeatedly pressed or separated, the groove 211 is not sharp at the bottom and is formed to be wider, which can suppress the generation or cracking of the groove 211 and improve the durability of the friction component 210.

[0084] As can be understood from the described operation, in the manufacturing method of the wet friction plate 200 according to the embodiment, even if the groove 211 is laser-processed, the groove 211 is crushed and the sides 212a and 212b are formed into a highly uneven surface, thereby improving the retention of lubricating oil in the groove 211.

[0085] Furthermore, the implementation of the present invention is not limited to the described embodiments, and various modifications can be made without departing from the scope of the present invention. In addition, in the following variations, structural portions identical to the wet friction plate 200 in the described embodiments are marked with symbols corresponding to those of the wet friction plate 200, and descriptions are omitted.

[0086] For example, in the embodiment described, the groove 211 is formed with a cross-sectional shape that is slightly V-shaped (triangular). However, the groove 211 is formed into a shape that deforms the inner surface 212 of the groove through a crushing process, so it can be formed into a shape other than V-shaped, such as U-shaped or arc-shaped, or other shapes.

[0087] Furthermore, in the aforementioned embodiment, the groove 211 is formed with a width of approximately 100 μm and a maximum depth of approximately 200 μm. However, the width of the groove 211 may also be formed to be between 10 μm and 1000 μm. Additionally, the depth of the groove 211 may also be formed to be between 10 μm and 1000 μm.

[0088] Furthermore, in the aforementioned embodiment, the groove 211 is formed on the friction member 210 in an arc shape that extends continuously along the circumferential direction of the core plate 201. However, the groove 211 may also extend in the radial direction or other directions of the core plate 201. In this case, the groove 211 may also extend continuously in a straight line or curve in the circumferential direction, radial direction or other directions of the core plate 201, or it may be formed in an intermittent straight line or curve shape.

[0089] Furthermore, in the aforementioned embodiment, the groove 211 is formed by three arcs arranged radially around the wet friction plate 200. In this case, the three arcs are concentric circles centered on the center of the core plate 201. However, it is sufficient to form at least one groove 211. Moreover, when the groove 211 is formed by multiple arcs arranged radially around the wet friction plate 200, it can of course be formed by arcs with different radii.

[0090] Furthermore, in the embodiment described above, in the process of forming the groove 211 in the second step, the groove 211 is formed with a cross-sectional shape that is slightly V-shaped (triangular). However, in the process of forming the groove 211 in the second step, shapes other than V-shaped can be formed, such as U-shaped, square, or arc-shaped, and other shapes.

[0091] Furthermore, in the aforementioned embodiment, the process of forming grooves 211 is performed on the friction element 210 before it is disposed on the core plate 201. Therefore, compared to machining grooves 211 on the friction element on the core plate, the operator can easily and precisely form the grooves 211. In this case, the operator can reliably prevent the grooves 211 from being incorrectly formed on the core plate 201. However, the process of forming grooves 211 can of course also be performed on the friction element 210 disposed on the core plate 201. Accordingly, the operator can precisely form the grooves 211 at the correct position on the core plate 201.

[0092] Furthermore, in the aforementioned embodiment, the crushing process of the groove 211 is performed on the friction element 210 disposed on the core plate 201. Therefore, the operator can also handle the process of attaching the friction element 210 to the core plate 201, reducing workload and efficiently manufacturing the wet friction plate 200. However, the crushing process of the groove 211 can, of course, also be performed on the friction element 210 previously disposed on the core plate 201. Accordingly, the operator can crush and shape different types of friction elements 210 or different types of grooves 211 using their respective processes.

[0093] Furthermore, in the aforementioned embodiment, the manufacturing process of the friction element 210 is performed in the first step. However, in the wet friction plate manufacturing method of the present invention, the papermaking body or the friction element 210 may also be purchased from the market and used instead of manufacturing the friction element 210.

[0094] Furthermore, in the aforementioned embodiment, during the manufacturing process of the friction element 210 in the first step, the thermosetting resin is hardened in a semi-hardened state. Therefore, during the crushing process of the groove 211 in the fourth step, the operator can suppress the rebound of the pressed friction element 210 and precisely crush the groove 211 to manufacture the wet friction plate 200. Moreover, in this case, the pressure applied to the friction element 210 during the crushing process of the groove 211 in the fourth step is reduced compared to pressing the friction element 210 when the thermosetting resin is fully hardened. However, the thermosetting resin can also be fully hardened during the manufacturing process of the friction element 210 in the first step. In this case, the crushing process of the groove 211 in the fourth step involves pressing the friction element 210 when the thermosetting resin is fully hardened and crushing the groove 211.

[0095] Furthermore, in the aforementioned embodiment, during the crushing process of the fine groove 211 in the fourth step, the friction element 210 is heated and pressed simultaneously. However, the crushing process of the fine groove 211 in the fourth step can also be performed without heating the friction element 210, only by pressing. Moreover, in this method of manufacturing the wet friction plate 200, the friction element 210 on the core plate 201 can be heated and adhered to the core plate 201 before pressing the friction element 210 and performing the crushing process of the fine groove 211.

[0096] Furthermore, in the described embodiment, a thermosetting resin is used as the adhesive for fixing the friction member 210 to the core plate 201. However, adhesives other than thermosetting resins can also be used as the adhesive for fixing the friction member 210 to the core plate 201. For example, as the adhesive, elastic adhesives (silicone-based or modified silicone-based, etc.), thermoplastic resin-based adhesives (polyvinyl alcohol-based, polyamide-based, or polyolefin-based, etc.), or inorganic adhesives (ceramic adhesives or sodium silicate, etc.) can be used.

[0097] Furthermore, in the aforementioned embodiment, the laser processing apparatus 300 is configured such that the laser head 301 can be displaced in three mutually orthogonal directions: the X-axis, Y-axis, and Z-axis. However, other structures can be used as long as the laser processing apparatus 300 is configured to form a groove 211 on the friction member 210. Therefore, for example, the laser processing apparatus 300 can be configured such that a current scanner or a polygonal reflector is provided inside the laser head 301, and the laser L is scanned in the X-axis and Y-axis directions respectively, replacing the displacement of the laser head 301 and / or the stage 302, or as an addition.

[0098] Furthermore, in the aforementioned embodiment, the friction element 210 is constructed from a papermaking body. However, the friction element 210 may also be constructed from materials other than paper, such as rubber or cork.

[0099] Furthermore, the described embodiment is based on an example of applying the wet friction plate of the present invention to the wet friction plate 200 used in a wet multi-plate clutch device 100. However, the wet friction plate of the present invention can be any type of wet friction plate used in oil, and in addition to the wet multi-plate clutch device 100, it can also be applied to wet friction plates used in braking devices that brake rotational motion caused by a prime mover.

[0100] Explanation of reference numerals in the attached figures

[0101] L: Laser

[0102] 100: Wet multi-plate clutch device

[0103] 101: Shell

[0104] 102: Input gear

[0105] 102a: Torque damper

[0106] 102b: Rivet

[0107] 103: Clutch plate

[0108] 104: Friction Plate Support

[0109] 104a: Cylindrical support column

[0110] 104b: Pressure-bearing section

[0111] 105: Shaft

[0112] 105a: Needle roller bearing

[0113] 105b: Nut

[0114] 106: Putter

[0115] 107: Push-up cap

[0116] 107a: Separation bearing

[0117] 108a: Bolt

[0118] 108b: Film holder

[0119] 108c: Compression spring

[0120] 200: Wet friction plate

[0121] 201: Core board

[0122] 202: Spline

[0123] 203: Oil tank

[0124] 210: Friction components

[0125] 211: Fine groove

[0126] 212: Inner surface of the groove

[0127] 212a, 212b: Side view

[0128] 300: Laser processing equipment

[0129] 301: Laser head

[0130] 302: Workbench

[0131] 303: Workpiece conveying mechanism

[0132] 400: Hot stamping processing equipment

[0133] 401: Lower pressure plate

[0134] 402: Upper pressure plate

[0135] 403: Movable support device

[0136] 403a: Lower matrix

[0137] 403b: Support column

[0138] 403c: Upper bottom plate

Claims

1. A method for manufacturing a wet friction pad, characterized in that, The wet friction pad is formed by arranging friction elements along the circumferential direction on the surface of a core plate that is formed into a flat ring shape. The manufacturing method of the wet friction pad includes: In the groove forming process, a laser is irradiated while being relatively displaced relative to the friction element, thereby forming concave grooves on the surface of the friction element; and In the crushing process, the friction element is pressed to crush and deform the fine groove formed by the laser, thereby forming the side of the fine groove into a concave-convex surface, which increases the surface area of ​​the inner surface of the groove.

2. The method for manufacturing a wet friction pad according to claim 1, characterized in that, It also includes a friction element configuration process for configuring the friction element on the core plate. The groove forming process is performed before the friction component configuration process.

3. The method for manufacturing a wet friction pad according to claim 2, characterized in that, The crushing process is performed on the friction element disposed on the core plate.

4. The method for manufacturing a wet friction pad according to claim 1, characterized in that, It also includes a friction element configuration process for configuring the friction element on the core plate. The groove forming process is performed on the friction element disposed on the core plate. The crushing process is performed on the friction element disposed on the core plate.

5. The method for manufacturing a wet friction pad according to any one of claims 1 to 4, characterized in that, It also includes a friction element manufacturing process in which a papermaking body is used as the friction element and is manufactured, wherein the papermaking body is an aggregate of numerous fibers impregnated with a thermosetting resin. The crushing process involves heating and pressing the friction component simultaneously.

6. The method for manufacturing a wet friction pad according to claim 5, characterized in that, The friction component manufacturing process involves manufacturing the paper body in a semi-cured state, where the thermosetting resin is cured to a degree that is not fully cured. The crushing process involves heating the friction component to completely harden the thermosetting resin in its semi-hardened state.

7. The method for manufacturing a wet friction pad according to claim 3 or 4, characterized in that, The friction component configuration process involves applying an adhesive between the core plate and the friction component. The crushing process involves pressing the friction element to adhere it to the core plate.

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