Patent Description:
Typically, a vehicle such as a four-wheeled vehicle or a two-wheeled vehicle has been equipped with a multiplate clutch device for transmitting rotary drive force of a motor such as an engine to a drive target such as a wheel or blocking such force transmission. Generally, in the multiplate clutch device, two plates, i.e., a drive-side plate and a driven-side plate, arranged facing each other are pressed against or separated from each other in lubricant oil, and in this manner, the rotary drive force is transmitted or blocked.

In this case, one of these two plates is a wet friction plate configured such that friction members are provided along a peripheral direction on a surface of an annular flat plate-shaped core. For example, at a clutch plate disclosed in Patent Literature <NUM> below, many recesses are formed at each side surface of a core plate as a core formed in an annular flat plate shape for the purpose of improving the adhesion strength of a facing as a friction member.

However, at the clutch plate described in Patent Literature <NUM> above, many recesses are formed by sandblasting. For this reason, there is a problem that the flatness of the core is degraded due to, e.g., an uneven density of collision of sand grains with the core, an uneven strength of such collision, and uneven formation of the recesses between both side surfaces of the core.

The present invention has been made for coping with the above-described problem. An object of the present invention is to provide a joint component formed with fine recessed portions so that degradation of the flatness of a metal base body, such as a core, to which a joint object such as a friction member is joined can be reduced, a multiplate clutch device including the joint component, and a joint component manufacturing method.

Document <CIT> describes a method of laser etching a metal clutch part for adhesion of wet friction material.

Document <CIT> relates to a multilayered friction disc with ceramic friction surfaces.

Document <CIT> relates to a structure of a clutch plate of an automatic transmission used for controlling the transmission of driving force in a vehicle.

Document <CIT> relates to a disc pad used in a braking member for an automobile.

In order to achieve the above object, as a feature of the present invention, there is provided a joint component including: a metal base body having a joint surface formed as a flat surface; and a j oint object to be joined to the j oint surface. The joint surface has a flatness of equal to or less than <NUM>, and is formed with many fine recessed portions formed in a recessed shape. The fine recessed portions are formed such that adjacent ones of the fine recessed portions do not overlap with each other and a formation density per unit area smaller than an area of the joint surface is uniform.

According to the feature of the present invention configured as described above, in the joint component, many fine recessed portions formed at the joint surface of the metal base body as a target to which the joint object is to be joined are formed not to overlap with each other and to have the uniform formation density per unit area. With this configuration, the flatness of the joint surface can be equal to or less than <NUM>. Note that the fine recessed portion is a bottomed hole or a through-hole opening at the joint surface with such a size that the fine recessed portion is within a circle with a diameter of <NUM> to <NUM>. Moreover, the unit area is the area of a square region as viewed in plane at the joint surface, and for example, is <NUM><NUM> or <NUM><NUM>.

Note that Patent Literature <NUM> above describes, with reference to <FIG> and <FIG>, a state in which adjacent ones of the recesses are formed not to overlap with each other at the core plate. However, the recesses in Patent Literature <NUM> above are formed by sandblasting. For this reason, it is impossible that the recesses are formed not to overlap with each other. That is, <FIG> and <FIG> in Patent Literature <NUM> above are schematically shown for the sake of understanding of the recesses formed at the core plate, and do not intended to disclose the invention of the present application.

Moreover, as another feature of the present invention, in the joint component, the fine recessed portions are formed such that a total opening area as viewed in plane in the unit area is equal to or greater than <NUM>% and equal to or less than <NUM>% with respect to the unit area.

According to another feature of the present invention configured as described above, in the joint component, the total opening area of the fine recessed portions as viewed in plane in the unit area is equal to or greater than <NUM>% and equal to or less than <NUM>% with respect to the unit area. With this configuration, the fine recessed portions can be easily formed not to overlap with each other and to have the uniform formation density per unit area.

Moreover, as another feature of the present invention, in the joint component, the fine recessed portions are formed such that a distance between adjacent ones of the fine recessed portions is uniform.

According to another feature of the present invention configured as described above, in the joint component, the distance between adjacent ones of the fine recessed portions is uniform. With this configuration, the fine recessed portions can be easily formed not to overlap with each other and to have the uniform formation density per unit area.

Moreover, as another feature of the present invention, in the joint component, the fine recessed portions are processing marks formed by laser light.

According to another feature of the present invention configured as described above, in the joint component, the fine recessed portions are the processing marks formed by laser light. With this configuration, the fine recessed portions can be easily formed not to overlap with each other and to have the uniform formation density per unit area. Moreover, since residual stress on the joint surface is less in laser processing than in sandblasting, degradation of the flatness of the joint surface can be reduced.

Moreover, as another feature of the present invention, in the joint component, the joint surface is formed in a circular or circular ring shape as viewed in plane, and the fine recessed portions are formed to be arranged in a spiral shape in a peripheral direction of the joint surface.

According to another feature of the present invention configured as described above, in the joint component, the joint surface is formed in the circular or circular ring shape as viewed in plane, and the fine recessed portions are formed so as to be arranged in the spiral shape in the peripheral direction of the joint surface. With this configuration, the fine recessed portions can be easily formed not to overlap with each other and to have the uniform formation density per unit area.

Moreover, as another feature of the present invention, in the joint component, the base body includes a core formed in an annular flat plate shape, the joint object includes a friction member bonded to a surface of the core along the peripheral direction, and the joint component includes friction plates arranged facing each other in a clutch device or a brake device and configured to closely contact or separate from each other to transmit or block rotary drive force between the friction plates.

According to another feature of the present invention configured as described above, in the joint component, the base body includes the core formed in the annular flat plate shape, and the joint object includes the friction member bonded to the surface of the core along the peripheral direction. With this configuration, the joint components can be formed as the friction plates arranged facing each other in the clutch device or the brake device and configured to closely contact or separate from each other to transmit or block the rotary drive force therebetween. That is, the invention of the present application can be also implemented as an invention relating to the friction plates arranged facing each other in the clutch device or the brake device and configured to closely contact or separate from each other to transmit or block the rotary drive force therebetween.

Moreover, as another feature of the present invention, in the joint component, a depth of each of the fine recessed portions from the joint surface is equal to or less than <NUM>.

According to another feature of the present invention configured as described above, in the joint component as the friction plate, the fine recessed portions are formed such that the depth of each fine recessed portion from the joint surface is equal to or less than <NUM>. With this configuration, degradation of the flatness of the thin friction plate can be effectively reduced.

Moreover, as another feature of the present invention, in the joint component, the fine recessed portions are formed only in a region, where the friction member is arranged, in a circular ring shape in the peripheral direction at the core.

According to another feature of the present invention configured as described above, in the joint component as the friction plate, the fine recessed portions are formed only in the region, where the friction member is arranged, in the circular ring shape in the peripheral direction at the core. With this configuration, the fine recessed portions can be efficiently formed, and degradation of the flatness of the thin friction plate can be effectively reduced.

According to the present invention, in the joint component, the fine recessed portions are also formed at a portion of the base body other than a portion to which the joint object is joined, and the base body includes a cover layer covering the fine recessed portions formed at the portion other than the portion to which the joint object is joined.

According to another feature of the present invention configured as described above, the joint component includes the cover layer covering the fine recessed portions formed at the portion of the base body other than the portion to which the joint object is joined. Since the fine recessed portions formed at the portion other than the portion to which the joint object is joined are covered, influence due to the fine recessed portions, specifically, e.g., degradation of the flowability of lubricant oil due to the fine recessed portions exposed through the core, can be reduced.

The present invention can be implemented not only as the invention relating to the joint component, but also as an invention relating to a multiplate clutch device including the joint component and an invention relating to a joint component manufacturing method.

Specifically, in the multiplate clutch device for transmitting or blocking rotary drive force between a drive-side plate to be rotatably driven by a motor and a driven-side plate arranged facing the drive-side plate through a clearance in such a manner that the drive-side plate and the driven-side plate closely contact or separate from each other, at least one of the drive-side plate or the driven-side plate may be the friction plate as the joint component provided in the clutch device according to any one of claims <NUM> to <NUM>. According to this configuration, features and advantageous effects similar to those of the above-described joint component can be expected from the multiplate clutch device.

Moreover, regarding the joint component manufacturing method for manufacturing a joint component configured such that a joint object is joined to a joint surface as a flat surface formed at a metal base body, the method may include: a base body preparation step of preparing the base body having the joint surface with a flatness of equal to or less than <NUM>; a fine recessed portion formation step of forming many fine recessed portions at least at the joint surface by irradiating the base body with laser light while relatively displacing the laser light; and a joint object joining step of joining the joint object to the joint surface. At the fine recessed portion formation step, the fine recessed portions may be formed in such arrangement that adjacent ones of the fine recessed portions do not overlap with each other and a formation density per unit area smaller than an area of the joint surface is uniform.

According to the present invention, the above joint component manufacturing method may further include a cover layer formation step of forming a cover layer covering the fine recessed portions.

Moreover, in the cases above, in the joint component manufacturing method, the joint surface may be formed in a circular or circular ring shape, and at the fine recessed portion formation step, the fine recessed portions may be formed to extend in a spiral shape along a peripheral direction of the joint surface. According to this joint component manufacturing method, features and advantageous effects similar to those of the above-described joint component can be expected.

Hereinafter, one embodiment of a joint component, a multiplate clutch device including the joint component, and a friction plate manufacturing method according to the present invention will be described with reference to the drawings. <FIG> is a sectional view showing the outline of an entire configuration of a multiplate clutch device <NUM> including friction plates <NUM> as joint components according to the present invention. Moreover, <FIG> is a plan view showing the outline of an external configuration of the friction plate <NUM> included in the multiplate clutch device <NUM> shown in <FIG>. Further, <FIG> is a partially-enlarged side view schematically showing a sectional view of the friction plate <NUM> along a <NUM>-<NUM> line shown in <FIG>. Note that each figure as a reference in the present specification is schematically shown for the sake of easy understanding of the present invention and, e.g., some components are exaggeratingly shown. For this reason, the dimensions, ratios, etc. of the components may vary. The multiplate clutch device <NUM> is a mechanical device for transmitting drive force of an engine (not shown) as a motor in a two-wheeled vehicle (a motorcycle) to a wheel (not shown) as a drive target or blocking such force transmission. The multiplate clutch device <NUM> is arranged between the engine and a transmission (not shown).

The multiplate clutch device <NUM> includes a housing <NUM> made of aluminum alloy. The housing <NUM> is a member formed in a bottomed cylindrical shape and forming part of a housing of the multiplate clutch device <NUM>. An input gear <NUM> is, with a rivet 102b, fixed to the left side surface of the housing <NUM> as viewed in the figure through a torque damper 102a. The input gear <NUM> is rotatably driven with the input gear <NUM> engaging with a not-shown drive gear which is rotatably driven by drive of the engine. On an inner peripheral surface of the housing <NUM>, multiple (eight in the present embodiment) clutch plates <NUM> are held by spline fitting so as to displace along an axial direction of the housing <NUM> and rotate integrally with the housing <NUM>.

The clutch plate <NUM> is an annular flat plate-shaped component to be pressed against the later-described friction plate <NUM>. The clutch plate <NUM> is formed in such a manner that a thin plate member made of a steel plate cold commercial (SPCC) material is punched into an annular shape. Not-shown oil grooves having depths of several µm to several tens of µm for holding later-described lubricant oil are formed at both side surfaces (front and back surfaces) of each clutch plate <NUM>. Moreover, for the purpose of improving abrasion resistance, surface hardening treatment is performed for both side surfaces (the front and back surfaces) of each clutch plate <NUM> formed with the oil grooves. Note that such surface hardening treatment does not directly relate to the present invention, and for this reason, description thereof will be omitted.

In the housing <NUM>, a friction plate holder <NUM> formed in a substantially cylindrical shape is arranged concentrically with the housing <NUM>. Many spline grooves are formed along an axial direction of the friction plate holder <NUM> at an inner peripheral surface of the friction plate holder <NUM>. A shaft <NUM> is spline-fitted in these spline grooves. The shaft <NUM> is a shaft body formed in a hollow shape. One (the right side as viewed in the figure) end side of the shaft <NUM> rotatably supports the input gear <NUM> and the housing <NUM> through a needle bearing 105a, and supports the spline-fitted friction plate holder <NUM> in a fixed manner through a nut 105b. That is, the friction plate holder <NUM> rotates integrally with the shaft <NUM>. On the other hand, the other (the left side as viewed in the figure) end side (not shown) of the shaft <NUM> is coupled to the not-shown transmission of the two-wheeled vehicle.

A shaft-shaped push rod <NUM> is arranged to penetrate a hollow portion of the shaft <NUM> with the push rod <NUM> protruding from the above-described one (the right side as viewed in the figure) end portion of the shaft <NUM>. Of the push rod <NUM>, a side (the left side as viewed in the figure) opposite to the end portion protruding from the one (the right side as viewed in the figure) end portion of the shaft <NUM> is coupled to a not-shown clutch operation lever of the two-wheeled vehicle. The push rod <NUM> slides along an axial direction of the shaft <NUM> in the hollow portion of the shaft <NUM> by operation of the clutch operation lever.

On an outer peripheral surface of the friction plate holder <NUM>, the multiple (seven in the present embodiment) friction plates <NUM> are held by spline fitting so as to displace along the axial direction of the friction plate holder <NUM> and rotate integrally with the friction plate holder <NUM> with each clutch plate <NUM> being sandwiched between adjacent ones of the friction plates <NUM>.

On the other hand, the inside of the friction plate holder <NUM> is filled with a predetermined amount of lubricant oil (not shown), and three tubular support rods 104a are formed in the friction plate holder <NUM> (the figure shows only one tubular support rod 104a). The lubricant oil is supplied to among the friction plates <NUM> and the clutch plates <NUM>, thereby absorbing friction heat generated among the friction plates <NUM> and the clutch plates <NUM> and preventing abrasion of friction members <NUM>.

Each of the three tubular support rods 104a is formed so as to protrude outwardly (the right side as viewed in the figure) in the axial direction of the friction plate holder <NUM>. A pressing cover <NUM> arranged at a position concentric with the friction plate holder <NUM> is assembled through a bolt 108a, a receiving plate 108b, and a coil spring 108c. The pressing cover <NUM> is formed in a substantially discoid shape having the substantially same outer diameter as the outer diameter of the friction plate <NUM>. The pressing cover <NUM> is pressed to a friction plate holder <NUM> side by the coil spring 108c. At a center portion inside the pressing cover <NUM>, a release bearing 107a is provided at a position facing the right tip end portion of the push rod <NUM> as viewed in the figure.

Specifically, as shown in each of <FIG>, the friction plate <NUM> includes each of oil grooves <NUM> and the friction members <NUM> on an annular flat plate-shaped core <NUM>. The core <NUM> is a member forming a base portion of the friction plate <NUM>. The core <NUM> is formed in such a manner that a thin plate member made of a steel plate cold commercial (SPCC) material is punched into a substantially annular shape. In this case, an internal gear-shaped spline <NUM> to be spline-fitted onto the friction plate holder <NUM> is formed at an inner peripheral portion of the core <NUM>.

At a side surface of the friction plate <NUM> facing the clutch plate <NUM>, i.e., a circular ring-shaped plate surface of the core <NUM> facing the clutch plate <NUM>, the friction members <NUM> are provided along a peripheral direction of the core <NUM> on a joint surface <NUM> through fine recessed portions <NUM> and a cover layer <NUM>.

The joint surface <NUM> is a portion to which the friction members <NUM> are joined, and is formed as a flat surface. In the present embodiment, the joint surface <NUM> is, as indicated by a hatched portion in <FIG>, formed in a circular ring shape outside the spline <NUM> in a radial direction at the plate surface of the core <NUM>. In this case, the joint surface <NUM> is formed with a slightly greater width than the width of the friction member <NUM> in the radial direction of the core <NUM>. Further, a portion formed with no small piece-shaped friction members <NUM> among the friction members <NUM> also forms the joint surface <NUM>. That is, the joint surface <NUM> is formed with a slightly greater width than the width of the friction member <NUM> in the radial direction of the core <NUM> in a circular ring shape continuously extending along the peripheral direction of the core <NUM>.

The joint surface <NUM> is formed at each surface of the core <NUM>, and is formed as a flat surface with a flatness of equal to or less than <NUM>. The flatness described herein is the degree of distortion of a planar shape from a geometrically-accurate flat surface, and is represented by a clearance between two parallel imaginary planes when the clearance between these two imaginary planes is minimum in a case where a surface as a measurement target is sandwiched between the two imaginary planes. The flatness can be measured by, e.g., a dial gauge, an optical flat (a plane gauge), or a measuring instrument using laser light.

Note that the joint surface <NUM> may be formed with the same width as the width of the friction member <NUM> in the radial direction of the core <NUM>, needless to say. Alternatively, the joint surface <NUM> may be formed only by a portion of the plate surface of the core <NUM> to which the friction members <NUM> are joined, i.e., a portion to which the friction members <NUM> are actually joined other than a portion formed with no small piece-shaped friction members <NUM> among the friction members <NUM>. In the present embodiment, the core <NUM> is formed with such flat surfaces that the flatness of the entirety of each surface including the joint surface <NUM> is equal to or less than <NUM>. Since the joint surface <NUM> is not clearly visible, the joint surface <NUM> is purposely hatched in <FIG>, but is not shown in <FIG>, and <FIG>.

The fine recessed portion <NUM> is a portion for improving joint force of the friction member <NUM> joined onto the joint surface <NUM>. The fine recessed portion <NUM> is formed in a shape recessed from the joint surface <NUM>. In this case, the fine recessed portion <NUM> opens with an extremely-small size at the joint surface <NUM>. Specifically, the fine recessed portion <NUM> opens with such a size that the fine recessed portion <NUM> is within a circle with a diameter of <NUM> to <NUM>. In the present embodiment, the fine recessed portion <NUM> opens in the shape of a circle with a diameter of <NUM> as viewed in plane.

The fine recessed portion <NUM> includes a bottomed hole. In the present embodiment, the fine recessed portion <NUM> is formed in such a spherical shape that a deepest portion of a bottom portion has a depth of <NUM>. Note that the fine recessed portion <NUM> may be formed so as to penetrate the core <NUM>.

The fine recessed portions <NUM> are formed such that adjacent ones of the fine recessed portions <NUM> at the joint surface <NUM> do not overlap with each other and a formation density per unit area Ua at the joint surface <NUM> is uniform. In this case, the "uniform formation density" does not mean that a certain number of fine recessed portions <NUM> is precisely formed at any position at the joint surface <NUM>, but means that the number of fine recessed portions <NUM> is substantially uniform across the joint surface <NUM>, needless to say. Specifically, the uniform formation density means a density within a range of ±<NUM>%. In the present embodiment, about <NUM> fine recessed portions <NUM> are formed within a square region of <NUM><NUM> as viewed in plane. Thus, the percentage of the total area of the fine recessed portions <NUM> in the unit area Ua as viewed in plane is about <NUM>%. Note that the unit area Ua is a virtual region set for the joint surface <NUM>.

The fine recessed portions <NUM> are arrayed in a spiral shape along the peripheral direction of the core <NUM>. In this case, the fine recessed portions <NUM> are formed at equal intervals along a spiral direction. The fine recessed portions <NUM> are formed as laser processing marks remaining after part of the surface of the core <NUM> has been removed in a recessed shape by laser light irradiation. Note that <FIG> and <FIG> described later exaggeratingly show the fine recessed portions <NUM>.

The oil groove <NUM> is not only a flow path for guiding the lubricant oil between an inner peripheral edge and an outer peripheral edge of the core <NUM> of the friction plate <NUM>, but also an oil holding portion for holding the lubricant oil between the friction plate <NUM> and the clutch plate <NUM>. The oil groove <NUM> is formed as a clearance between adjacent ones of the friction members <NUM>. In the present embodiment, the oil grooves <NUM> include a fan-shaped portion between adjacent groups of three small piece-shaped friction members <NUM> and a linear portion between adjacent ones of three friction members <NUM> arranged between adjacent two of the fan-shaped oil grooves <NUM>.

The cover layer <NUM> is a portion covering the fine recessed portions <NUM> formed at a portion of the core <NUM> provided with no friction members <NUM>. Specifically, the cover layer <NUM> is made of a thermosetting resin adhesive, and is formed with a substantially uniform thickness across the entirety of each surface of the core <NUM>. In the present embodiment, the cover layer <NUM> is also formed on each side surface of the spline <NUM>.

The cover layer <NUM> is formed with such a thickness that at least the depth of the fine recessed portion <NUM> is decreased by application of the cover layer <NUM>. Specifically, the cover layer <NUM> preferably has a thickness of equal to or greater than <NUM> and equal to or less than <NUM> and more preferably equal to or greater than <NUM> and equal to or less than <NUM>. In the present embodiment, the cover layer <NUM> is formed with a thickness of <NUM> from the surface of the core <NUM>. In this case, the cover layer <NUM> is formed transparent or translucent to such an extent that a person can visually recognize the surface of the core <NUM>.

As the thermosetting resin forming the cover layer <NUM>, phenol resin, modified phenol resin, epoxy resin, urea resin, unsaturated polyester resin, polyurethane resin, or polyimide resin may be used. In the present embodiment, the cover layer <NUM> is made of phenol resin. Alternatively, as the resin forming the cover layer <NUM>, various elastomers (e.g., nitrile rubber-based elastomer or chloroprene rubber-based elastomer) may be used other than the thermosetting resin. In this case, the resin forming the cover layer <NUM> does not necessarily have adhesion properties. That is, it may only be required that the cover layer <NUM> is made of such resin that at least the depth of the fine recessed portion <NUM> can be decreased by application of the resin. As a material for fixing the friction member <NUM> onto the core <NUM>, an adhesive made of a substance different from the resin forming the cover layer <NUM> may be used.

The friction member <NUM> improves friction force against the clutch plate <NUM>. The friction member <NUM> is made of a small piece-shaped paper material bonded along the peripheral direction of the core <NUM>. In the present embodiment, the friction members <NUM> are formed such that eight small piece groups are arranged in the peripheral direction of the core <NUM> through eight fan-shaped oil grooves <NUM>. In each small piece group, three rectangular small pieces extending in the peripheral direction of the core <NUM> are arranged in the peripheral direction of the core <NUM> through two linear oil grooves <NUM>. Note that it may only be required that the friction member <NUM> is made of a material capable of improving the friction force between the friction plate <NUM> and the clutch plate <NUM>. The friction member <NUM> may be made of a material other than the paper material, such as a cork material, a rubber material, or a glass material. Note that in <FIG>, the friction members <NUM> are illustrated as darker-shaded areas.

Next, the method for manufacturing the friction plate <NUM> configured as described above will be briefly described with reference to <FIG>. First, a worker prepares, as a first step, each of the core <NUM> and the friction members <NUM>. Specifically, as shown in <FIG>, the worker forms, by pressing performed separately, the core <NUM> into a circular ring shape having the spline <NUM>.

Such pressing is the well-known processing technique of punching a metal (e.g., a SPCC material) thin plate member as the material of the core <NUM> into a circular ring shape by means of a die. In this case, the worker uses a plate member with a flatness of equal to or less than <NUM> as the metal thin plate member which is the material of the core <NUM>. In this manner, the worker can obtain the flat plate-shaped core <NUM> having the flat joint surfaces <NUM> with a flatness of equal to or less than <NUM>. That is, the step of preparing the core <NUM> at the first step is equivalent to a base body preparation step according to the present invention. The friction members <NUM> are formed in a band shape by papermaking performed separately. Papermaking for the friction members <NUM> is a typical well-known technique, and therefore, description thereof will be omitted.

Next, the worker forms, as a second step, the fine recessed portions <NUM> at each surface of the core <NUM>. In this case, the worker forms, as shown in <FIG>, the fine recessed portions <NUM> by means of a laser processing device <NUM>. The laser processing device <NUM> described herein is a mechanical device for forming the fine recessed portions <NUM> by irradiation of the core <NUM> with laser light L. The laser processing device <NUM> is a well-known mechanical device, and detailed description thereof will be omitted. Note that the configuration thereof will be briefly described.

The laser processing device <NUM> mainly includes each of a laser oscillator (not shown), a laser adjustment optical system (not shown), a laser head <NUM>, a work table <NUM>, and a control device (not shown). The laser oscillator is a mechanical device for emitting the laser light L for removing the surface of the core <NUM> in a recessed shape and forming the fine recessed portions <NUM> accordingly. In the present embodiment, the laser oscillator is an oscillator having a frequency of <NUM> and an output power of <NUM> W and configured to oscillate pulse laser light with a short pulse width such as a pulse width of nanoseconds, picoseconds, or femtoseconds. The laser adjustment optical system includes an optical component including various optical elements such as a lens and a mirror, an optical fiber, and the like, and the optical component guides the laser light L, emitted from the laser oscillator, to the laser head <NUM> while performing various types of adjustment such as correction of a beam diameter, a beam shape, and an aberration.

The laser head <NUM> is an optical device configured to emit the laser light L, which has been guided from the laser adjustment optical system, toward the work table <NUM> to collect the laser light L onto the core <NUM>. The laser head <NUM> is configured displaceable in three axial directions of an X-axis direction, a Y-axis direction, and a Z-axis direction perpendicular to each other relative to the work table <NUM>. The work table <NUM> is a device detachably holding the core <NUM>, to which the friction members <NUM> are bonded, at a position facing the laser head <NUM>. Note that the laser head <NUM> and the work table <NUM> are in a relative positional relationship. Thus, a configuration in which the work table <NUM> is displaceable instead of the laser head <NUM> may be employed, needless to say.

The control device includes a microcomputer having a CPU, a ROM, a RAM, and the like, and controls actuation of the entirety of the laser processing device <NUM> in an integrated manner. Specifically, the control device controls, according to a worker's instruction, actuation of each of the laser oscillator, the laser adjustment optical system, and the laser head <NUM> to displace the laser light L onto the core <NUM> during irradiation, thereby forming the fine recessed portions <NUM>.

At this second step, the worker holds the core <NUM> on the work table <NUM>. Thereafter, the worker instructs the control device of the laser processing device <NUM> to process the fine recessed portions <NUM>. In response to such an instruction, the control device displaces the laser head <NUM> in the X-axis direction and the Y-axis direction while the laser light L is being emitted from the laser head <NUM>, thereby displacing the laser light L on the core <NUM> to form the fine recessed portions <NUM>.

Specifically, the control device starts, as shown in <FIG>, irradiating an innermost peripheral portion of the joint surface <NUM> of the core <NUM> with the laser light L. Starting from a position P<NUM>, the control device displaces the laser head <NUM> in a spiral pattern extending gradually outwardly in the radial direction, and when the laser head <NUM> reaches a position P<NUM> of an outermost peripheral portion of the joint surface <NUM>, stops emission of the laser light L. In this manner, many fine recessed portions <NUM> are formed in the spiral shape along the peripheral direction at the joint surface <NUM> of the core <NUM>.

In this case, at the joint surface <NUM> of the core <NUM>, the fine recessed portions <NUM> are formed such that adjacent ones of the fine recessed portions <NUM> do not overlap with each other and the formation density per unit area Ua is uniform. Thus, the flatness (equal to or less than <NUM>) of the entirety of the side surface including the joint surface <NUM> can be maintained. Note that in the present embodiment, each fine recessed portion <NUM> is formed by one processing mark formed by a single pulse of laser light L emitted from the laser head <NUM>. One fine recessed portion <NUM> may be formed by multiple processing marks (i.e., two or more pulses of laser light L). Note that in <FIG>, the circular path of displacement of the laser light L is indicated by a dashed line.

Subsequently, the worker takes the core <NUM> from the work table <NUM>. Accordingly, the process of forming the fine recessed portions <NUM> on one side of the core <NUM> ends. Thus, the worker turns over the core <NUM> formed with the fine recessed portions <NUM>, and performs a similar process for another surface to form the fine recessed portions <NUM>. In this manner, the worker can form the fine recessed portions <NUM> at each j oint surface <NUM> of the core <NUM>. That is, the second step is equivalent to a fine recessed portion formation step according to the present invention.

Next, the worker forms, as a third step, the cover layer <NUM> on each of the two plate surfaces of the core <NUM>. Specifically, the worker heats and dries, as shown in <FIG>, a resin layer raw material containing liquid thermosetting resin as the raw material of the cover layer <NUM> after the resin layer raw material has been applied to the entirety of each of the two plate surfaces of the core <NUM> by means of a tool such as a brush or a roller. In this manner, the cover layer <NUM> made of the hardened resin layer raw material can be formed. In this case, the worker coats the surface of the core <NUM> once or overcoats the surface of the core <NUM> multiple times, thereby forming the cover layer <NUM>. The third step is equivalent to a cover layer formation step according to the present invention.

Next, the worker bonds, as a fourth step, the friction members <NUM> to each of the two plate surfaces of the core <NUM>. Specifically, the worker applies a liquid adhesive (not shown) to the entirety of each of the two cover layers <NUM> on the core <NUM> by means of a tool such as a brush or a roller. Thereafter, the worker places the friction members <NUM> before the adhesive is dried, and then, dries the adhesive. In the present embodiment, a resin layer raw material containing the same liquid thermosetting resin as the raw material of the cover layer <NUM> is used as the adhesive. That is, the resin raw material forming the cover layer <NUM> is made of the adhesive.

In this case, the worker may cut, after the friction members <NUM> have been placed on the core <NUM>, the band-shaped friction members <NUM> placed on the core <NUM>, thereby forming the friction members <NUM> into the small piece shape. Alternatively, the worker may place the friction members <NUM>, which are formed in the small piece shape in advance, on the core <NUM>. In this manner, the friction members <NUM> are fixed onto the cover layers <NUM> on the core <NUM>. The fourth step is equivalent to a joint object joining step according to the present invention.

Note that at the fourth step, the worker may apply the adhesive only to positions at which the friction members <NUM> are to be arranged or only onto the circular ring-shaped j oint surface <NUM>. Alternatively, the worker may apply the adhesive to a friction member <NUM> side instead of or in addition to application of the adhesive to the core <NUM>. Thereafter, the worker performs a friction property adjustment step and an inspection step, thereby completing the friction plate <NUM>. These steps do not directly relate to the present invention, and therefore, description thereof will be omitted.

Next, actuation of the multiplate clutch device <NUM> and the friction plate <NUM> configured as described above will be described. As described above, the friction plates <NUM> are used with the friction plates <NUM> being assembled into the multiplate clutch device <NUM>. The multiplate clutch device <NUM> is, as described above, arranged between the engine and the transmission in the vehicle, thereby transmitting the drive force of the engine to the transmission or block such force transmission according to operation of the clutch operation lever by a driver of the vehicle.

That is, in a case where the driver (not shown) of the vehicle operates the clutch operation lever (not shown) to retract (displace to the left side as viewed in the figure) the push rod <NUM>, the push rod <NUM> is brought into a state in which the tip end portion thereof does not press the release bearing 107a, and the pressing cover <NUM> presses the clutch plates <NUM> by elastic force of the coil spring 108c. Accordingly, the clutch plates <NUM> and the friction plates <NUM> are pressed against each other while displacing to a receiving portion 104b side, a receiving portion 104b being formed in a flange shape at the outer peripheral surface of the friction plate holder <NUM>. Accordingly, the clutch plates <NUM> and the friction plates <NUM> are brought into a friction-coupled state. As a result, the drive force of the engine transmitted to the input gear <NUM> is transmitted to the transmission through the clutch plates <NUM>, the friction plates <NUM>, the friction plate holder <NUM>, and the shaft <NUM>.

Since the friction members <NUM> are firmly joined to the core <NUM> through the fine recessed portions <NUM>, the friction plates <NUM> can transmit the rotary drive force to the clutch plates <NUM> with a favorable accuracy in a state in which the clutch plates <NUM> and the friction plates <NUM> friction-contact each other.

On the other hand, in a case where the driver of the vehicle operates the clutch operation lever (not shown) to advance (displace to the right side as viewed in the figure) the push rod <NUM>, the push rod <NUM> is brought into a state in which the tip end portion thereof presses the release bearing 107a, and the pressing cover <NUM> displaces to the right side as viewed in the figure against the elastic force of the coil spring 108c to separate from and the clutch plates <NUM>. Accordingly, the clutch plates <NUM> and the friction plates <NUM> displace to a pressing cover <NUM> side, and a state in which these plates are pressed against and coupled to each other is cancelled. Thus, the clutch plates <NUM> and the friction plates <NUM> are separated from each other. As a result, the drive force is no longer transmitted from the clutch plates <NUM> to the friction plates <NUM>, and transmission of the drive force, which has been transmitted to the input gear <NUM>, of the engine to the transmission is blocked.

In a state in which the clutch plates <NUM> and the friction plates <NUM> are separated from each other, the friction members <NUM> are also firmly joined to the core <NUM> through the fine recessed portions <NUM> at the friction plates <NUM>. Thus, neither detachment of the friction member <NUM> from the core <NUM> nor partial twisting or floating of the friction member <NUM> is caused. At the friction plate <NUM>, the fine recessed portions <NUM> formed at a portion of the joint surface <NUM> of the core <NUM> provided with no friction members <NUM>, such as the oil groove <NUM>, are covered with the adhesive for the friction member <NUM>. Thus, degradation of the flowability of the lubricant oil can be prevented.

As can be understood from description of actuation above, according to the above-described embodiment, in the multiplate clutch device <NUM> including the friction plates <NUM> as the joint components, many fine recessed portions <NUM> formed at the joint surfaces <NUM> of the metal core <NUM> as a target to which the friction members <NUM> as joint objects are joined are formed not to overlap with each other and to have the uniform formation density per unit area Ua. With this configuration, the flatness of the joint surface <NUM> can be equal to or less than <NUM>.

Further, implementation of the present invention is not limited to the above-described embodiment, and various changes can be made without departing from the object of the present invention.

For example, in the above-described embodiment, the fine recessed portion <NUM> is formed so as to open in the shape of the circle with a diameter of <NUM> as viewed in plane. However, it may only be required that the fine recessed portion <NUM> is formed so as to open with such a size that the fine recessed portion <NUM> is within the circle with a diameter of <NUM> to <NUM>. Thus, the fine recessed portion <NUM> may be formed in a shape other than the circular or oval shape, such as a quadrangular or triangular shape.

In the above-described embodiment, the fine recessed portion <NUM> is formed in such a spherical shape that the deepest portion of the bottom portion has a depth of <NUM>. However, the fine recessed portion <NUM> may be formed such that the depth from the joint surface <NUM> to the bottom portion may be less than <NUM> or equal to or greater than <NUM>. Alternatively, in the fine recessed portion <NUM>, the bottom portion may be formed in a shape other than the spherical shape, such as a quadrangular or pyramid shape. Note that in a case where the fine recessed portions <NUM> are formed at the core <NUM>, the depth of the fine recessed portion <NUM> is preferably equal to or greater than <NUM> and equal to or less than <NUM> and more preferably equal to or less than <NUM>.

In the above-described embodiment, the fine recessed portions <NUM> are formed such that the total opening area as viewed in plane is <NUM>% with respect to the unit area Ua. However, it may only be required that the fine recessed portions <NUM> are formed such that at least the formation density per unit area Ua is uniform at any position in a region formed with the fine recessed portions <NUM>. Thus, the fine recessed portions <NUM> may be formed such that the total opening area as viewed in plane is less than <NUM>% or exceeds <NUM>% with respect to the unit area Ua. In this case, the fine recessed portions <NUM> are preferably formed such that the total opening area as viewed in plane is equal to or greater than <NUM>% and equal to or less than <NUM>% with respect to the unit area Ua. Moreover, it may only be required that the fine recessed portions <NUM> are formed such that adjacent ones of the fine recessed portions <NUM> do not overlap with each other, i.e., are separated from each other. Note that the fine recessed portions <NUM> may be formed such that adjacent ones of the fine recessed portions <NUM> contact each other.

In the above-described embodiment, the fine recessed portions <NUM> are formed so as to be arrayed in the spiral shape along the peripheral direction of the core <NUM>. However, it may only be required that the fine recessed portions <NUM> are formed such that adjacent ones of the fine recessed portions <NUM> do not overlap with each other and the formation density per unit area Ua smaller than the area of the joint surface is uniform. Thus, as shown in, e.g., <FIG>, the fine recessed portions <NUM> may be formed so as to be arranged linearly along each of two directions (the right-left and upper-lower directions as viewed in the figure) perpendicular to each other at the center of the core <NUM>. Alternatively, as shown in, e.g., <FIG>, the fine recessed portions <NUM> may be formed such that a certain line of the fine recessed portions <NUM> arranged linearly in the right-left direction as viewed in the figure is arranged so as to be shifted from an adjacent line of the fine recessed portions <NUM> in an arrangement direction. Alternatively, as shown in, e.g., <FIG>, the fine recessed portions <NUM> may be formed such that a distance between adjacent ones of the fine recessed portions <NUM> is uniform. Alternatively, as shown in, e.g., <FIG>, the fine recessed portions <NUM> may be formed such that adjacent ones of the fine recessed portions <NUM> are arranged in an annular shape. As an alternative other than those described above, the fine recessed portions <NUM> may be formed so as to be arranged in a radial or circular ring shape. Note that <FIG> show only some of many fine recessed portions <NUM> formed at the joint surface <NUM>.

In the above-described embodiment, the fine recessed portions <NUM> are processed using the pulse laser light L. However, the fine recessed portions <NUM> may be formed using a processing method other than laser processing. For example, the fine recessed portions <NUM> may be also formed by discharging. Thus, the fine recessed portions <NUM> may be processing marks other than the processing marks formed by the laser light.

In the above-described embodiment, the joint surface <NUM> of the core <NUM> is formed such that the flatness thereof is equal to or less than <NUM>. However, it may only be required that the joint surface <NUM> is formed such that the flatness thereof is equal to or less than at least <NUM>. Thus, the joint surface <NUM> may be formed such that the flatness thereof is equal to or greater than <NUM> and equal to or less than <NUM> or the flatness thereof is less than <NUM>. Alternatively, the joint surface <NUM> may be formed only on one side of the core <NUM>. That is, the fine recessed portions <NUM> may be formed only on one side of the core <NUM>.

In the above-described embodiment, the cover layer <NUM> is formed across the entirety of each surface of the core <NUM>. However, it may only be required that the cover layer <NUM> is formed at least on the fine recessed portions <NUM> on which no friction members <NUM> are arranged. In this case, the fine recessed portions <NUM> may be filled with the cover layer <NUM>, and the cover layer <NUM> may be formed in a layer shape on the surface of the core <NUM>. Alternatively, part or the entirety of the fine recessed portions <NUM> may be filled with the cover layer <NUM>, and the cover layer <NUM> is not necessarily formed on the surface of the core <NUM>.

In the above-described embodiment, the friction plate <NUM> is formed such that the fine recessed portions <NUM> are covered with the cover layers <NUM>. However, the friction plate <NUM> may be formed without the cover layers <NUM>. That is, the cover layer formation step may be omitted from the steps of manufacturing the friction plate. The cover layer <NUM> is made of the resin material having the adhesion properties for the friction member <NUM>. However, the cover layer <NUM> does not necessarily have the adhesion properties, and may be made of a resin material having no adhesion properties for the friction member <NUM>. Alternatively, the cover layer <NUM> may be formed opaque.

In the above-described embodiment, the friction members <NUM> are provided in such a manner that the multiple small pieces are discontinuously arranged along the peripheral direction of the core <NUM> through the clearances forming the oil grooves <NUM>. However, the friction members <NUM> are provided as necessary according to the specifications of the multiplate clutch device <NUM>. Thus, the friction member <NUM> may be formed in a circular ring shape continuously extending in the peripheral direction of the core <NUM>. That is, the friction plate <NUM> may be formed without the oil grooves <NUM>.

In the above-described embodiment, the friction plates <NUM> are held by the friction plate holder <NUM> to be rotatably driven integrally with the shaft <NUM>. That is, the friction plate <NUM> is applied as an opposing plate, and the opposing plate is arranged facing the clutch plate <NUM> to be rotatably driven by the rotary drive force of the engine and is rotatably driven integrally with the shaft <NUM> as an output shaft in the multiplate clutch device <NUM>. However, the friction plate <NUM> may be also applied to the clutch plate <NUM> as a drive-side plate to be rotatably driven by the rotary drive force of the engine.

In the above-described embodiment, the laser processing device <NUM> is configured to displace the laser head <NUM> in the three axial directions of the X-axis direction, the Y-axis direction, and the Z-axis direction perpendicular to each other. However, other configurations may be employed as long as the laser processing device <NUM> is configured so that fine recessed portions <NUM> can be formed at the friction members <NUM> on the core <NUM>. Thus, the laser processing device <NUM> may include, for example, a galvanoscanner or a polygon mirror in the laser head <NUM> to scan the laser light in each of the X-axis direction and the Y-axis direction instead of or in addition to displacement of the laser head <NUM> and/or the work table <NUM>. Alternatively, the laser processing device <NUM> may be configured such that the core <NUM> to which the friction members <NUM> are bonded is held on the work table <NUM> configured movable or fixed and the core <NUM> is rotatably driven on the work table <NUM> or is scanned in each of the X-axis direction and the Y-axis direction.

In the above-described embodiment, the friction plate <NUM> is applied to the wet multiplate clutch device <NUM> to be rotatably driven in the lubricant oil. However, the friction plate <NUM> may be also applied to a dry multiplate clutch device <NUM> using no lubricant oil. Alternatively, the friction plate <NUM> may be also applied as a friction plate used for a clutch device (not shown) provided in a torque converter configured to amplify drive force from an engine to an output shaft side to transmit such force. Alternatively, the friction plate <NUM> may be also applied to a friction plate used for a brake device (not shown) configured to put a brake on rotary motion by a motor.

In the above-described embodiment, the example where the joint component according to the present invention is applied as the friction plate <NUM> has been described. That is, the core <NUM> in the above-described embodiment is equivalent to a base body according to the present invention, and the friction member <NUM> in the above-described embodiment is equivalent to the joint object according to the present invention. However, the present invention can be broadly applied to a joint component configured such that a joint object is joined to a planar joint surface formed at a metal base body.

Claim 1:
A joint component comprising:
a metal base body having a joint surface (<NUM>) formed as a flat surface; and
a joint object to be joined to the joint surface (<NUM>),
wherein the joint surface (<NUM>) has a flatness of equal to or less than <NUM>, and is formed with many fine recessed portions (<NUM>) formed in a recessed shape, and
the fine recessed portions (<NUM>) are formed such that adjacent ones of the fine recessed portions (<NUM>) do not overlap with each other and a formation density per unit area smaller than an area of the joint surface (<NUM>) is uniform;
wherein the base body includes a core (<NUM>) formed in an annular flat plate shape,
the joint object includes a friction member (<NUM>) bonded to a surface of the core (<NUM>) along the peripheral direction, and
the joint component includes friction plates (<NUM>) arranged facing each other in a clutch device or a brake device and configured to closely contact or separate from each other to transmit or block rotary drive force between the friction plates (<NUM>);
wherein the fine recessed portions (<NUM>) are also formed at a portion of the base body other than a portion to which the joint object is joined, and
the base body includes a cover layer (<NUM>) covering the fine recessed portions (<NUM>) formed at the portion other than the portion to which the joint object is joined.