Title of Invention

A METHOD OF MANUFACTURING A MEMBER OF A V-BELT PULLEY

Abstract

The present invention provides a method of manufacturing a member of a V- belt pulley, comprising the steps of pressing a pulley disk having a central fitting hole defIned therein and spreading outwardly and having a transmission web with a side thereof for contact with a V belt, forging or forging and machining a tubular shaft to a completed shape, press fitting said tubular shaft into said central fitting hole, integrally joining inter fitting surfaces of said tubular shaft and said pulley disk by laser beam welding, and surface-treating said tubular shaft and said pulley disk which have been joined to each other

Full Text

V-BELT PULLEY MEMBER AND METHOD OF MANUFACTURING SAME The present invention relates to the art of manufacturing a member of a V-belt drive, driven, or movable driven pulley for use in a continuously variable transmission for a scooter or the like. As shown in FIG. 1 of the accompanying drawings, one conventional continuously variable transmission for a scooter or the like comprises a drive pulley 1 coupled to the output shaft of an engine, a driven pulley 2 positioned downstream of the drive pulley 1 along a power output path, and a V belt 3 trained around the pulleys 1, 2 and radially adjustable with respect to the pulleys 1, 2 to change its winding position and attitude on the pulleys 1, 2 depending on the speed of rotation of the output shaft of the engine. The pulleys 1, 2 comprise respective pulley members la, lb and 2a, 2b with the V belt 3 wedged therebetween. The distance between the pulley members la, lb and 2a, 2b is increased or reduced to adjust the radially wedged position of the V belt 3 with respect to the pulleys 1, 2. Each of the pulley members la, lb and 2a, 2b comprises a pulley disk held in contact with one side of the V belt 3 and a tubular shaft fitted in a hole defined centrally in the pulley disk. The pulley disk and the tubular shaft are fixed to each other by either a combination of plasma arc welding and silver alloy brazing processes or a plasma arc welding process using a filler wire of SUS or mild steel. For example, the drive pulley member la is constructed as shown in FIG. 2(B) of the accompanying drawings. Specifically, as shown in FIG. 2(B), a drive face 4 as the pulley disk and a boss 5 as the tubular shaft are joined to each other by a weld bead "b" formed between an outer surface of a transmission web 4b of the drive face 4 and the boss 5 according to a plasma arc welding process using a filler wire of SUS309L. The driven pulley member 2a is constructed as shown in FIG. 3(B) of the accompanying drawings. Specifically, as shown in FIG. 3(B), a driven face 6 as the pulley disk and a boss 7 as the tubular shaft are joined to each other by a weld bead "c" between an outer surface of a transmission web 6b of the driven face 6 and the boss 7 according to a plasma arc welding process and also by a weld bead "d" formed between an inner surface of the transmission web 6b and the boss 7 according to a silver alloy brazing process. The driven pulley member 2b is constructed as shown in FIG. 4(B) of the accompanying drawings. Specifically, as shown in FIG. 4(B), a movable driven face 8 as the pulley disk and a cam 9 as the tubular shaft are joined to each other by a weld bead "e" formed between an inner surface of a transmission web 8b of the movable driven face 8 and the cam 9 according to a plasma arc welding process using a filler wire of mild steel. The combination of such plasma arc welding and silver alloy brazing processes or the plasma arc welding process using a filler wire poses large thermal strains on the welded joint because it is time-consuming and requires the workpieces to be heated for a long period of time. Therefore, it is necessary to remove such large thermal strains subsequently to the welding procedure, and to machine the bosses 5, 7 and the cam 9 after the welding procedure. As a result, the combination of such plasma arc welding and silver alloy brazing processes or the plasma arc welding process using a filler wire cannot be simplified in operation. The boss 7 of the pulley member 2a shown in FIG. 3(B) is subject to high-frequency induction hardening before it is welded to the driven face 6. The annealed boss 7, however, tends to be annealed in the welding procedure because the boss 7 is welded for a long period of time and exposed to repeated heating. As shown in FIGS. 9(A) and 9(B) of the accompanying drawings, the driven face 6 of the driven pulley member 2a is of such a shape which is liable to suffer localized stresses concentrated on a point X near a fitting surface "f' under a load W that is imposed on a point P by the V belt 3. If the fitting surface "f is welded to the boss 7 by laser beam welding in order to eliminate thermal strains and simplify the welding operation, then the driven face 6 and the boss 7 may not be joined with each other for a sufficient level of welded strength. It is therefore an object of the present invention to provide a member of a V-belt pulley which is constructed of a pulley disk and a tubular shaft that can be joined quickly, is subject to reduced thermal strains, can be welded in a greatly simplified process, and is highly resistant to applied loads. According to an aspect of the present invention, there is provided a member of a V-belt pulley, comprising a pressed pulley disk having a central fitting hole defined therein and spreading outwardly and including a transmission web with a side thereof held for contact with a V-belt, and a tubular shaft fitted in the central fitting hole, the tubular shaft and the pulley disk having interfitting surfaces integrally joined to each other by laser beam welding. The above aspect of the present invention is applicable to members of drive, driven, and movable driven pulleys. Since the interfitting surfaces are joined to each other laser beam welding, the members can be manufactured quickly, and any thermal strains thereof are minimized, dispensing with a process of removing thermal strains. Machining steps after the welding process are simplified, the number of manufacturing steps can be reduced, and some of the manufacturing steps can be omitted or shortened for increased productivity. According to another aspect of the present invention, there is also provided a member of a V-belt pulley, comprising a pressed pulley disk having a central fitting hole defined therein and spreading outwardly and including a transmission web with a side thereof for contact with a V belt, and a tubular shaft fitted in the central fitting — A hole, the tubular shaft being forged or forged and machined to a completed shape, the tubular shaft and the pulley disk having interfitting surfaces integrally joined to each other by laser beam welding. The above aspect of the present invention is applicable to a member of a drive pulley. The tubular shaft is machined to a completed shape before being welded to the pulley disk. Therefore, the machining steps for machining the tubular shaft are carried out before the welding process, and the number of manufacturing steps can be reduced, and some of the manufacturing steps can be omitted or shortened. The completed shape is a shape finished to the extent that no subsequent machining on the ends of the tubular shaft and no subsequent removal of thermal strains, for example, will be required. Since laser beam welding is used, any machining after the welding process is not necessary. According to still another aspect of the present invention, there is provided a member of a V-belt pulley, comprising a pressed pulley disk having a central fitting hole defined therein and spreading outwardly and including a transmission web with a side thereof for contact with a V belt, and a tubular shaft fitted in the central fitting hole, the tubular shaft being forged, machined on inner and outer edges thereof, processed by high-frequency induction hardening, and ground to a completed shape, the tubular shaft and the pulley disk having interfitting surfaces integrally joined to each other by laser beam welding. The above aspect of the present invention is applicable to a member of a driven pulley. Because the machining steps for machining the tubular shaft are carried out before the welding process, the number of manufacturing steps can be reduced, and some of the manufacturing steps can be omitted or shortened. The completed shape is a shape finished to the extent that no subsequent precision machining on the inner edge of the tubular shaft and no subsequent removal of thermal strains, for example, will be required. According to yet still another aspect of the present invention, there is provided a member of a V-belt pulley, comprising a pressed pulley disk having a central fitting hole defined therein and spreading outwardly and including a transmission web with a side thereof for contact with a V belt, and a tubular shaft fitted in the central fitting hole, the tubular shaft being forged and machined on inner and outer edges thereof to a completed shape, the tubular shaft and the pulley disk having interfitting surfaces integrally joined to each other by laser beam welding. The above aspect of the present invention is applicable to a member of a movable driven pulley. Because the machining steps for machining the tubular shaft are carried out before the welding process, the number of manufacturing steps can be reduced, and some of the manufacturing steps can be omitted or shortened. The completed shape is a shape finished to the extent that no subsequent precision machining on the inner edge of the tubular shaft and no subsequent removal of thermal strains, for example, will be required. According to a further aspect of the present invention, there is provided a member of a V-belt pulley, comprising a pressed pulley disk having a central fitting hole defined therein and spreading outwardly and including a transmission web with a side thereof for contact with a V belt, and a tubular shaft fitted in the central fitting hole and joined to the pulley disk, the pulley disk having a wavy surface region extending from a fitting surface thereof which is fitted over the tubular shaft, the wavy surface region comprising a first annular ridge contiguous to the fitting surface and projecting axially toward a face side of the transmission web, and a second annular ridge contiguous to and radially outward of the first annular ridge and projecting axially away from the face side of the transmission web. The above aspect of the present invention is applicable to a member of a driven pulley. The first and sec- ond annular ridges extend concentrically over a full circumferential length of the pulley disk. The wavy surface region serves as a rigid region for distributing a load transmitted from the transmission web in a wide range to prevent stresses from concentrating on a localized area particularly in the fitting surface. The pulley disk with the wavy surface region and the tubular shaft have interfitting surfaces integrally joined to each other by laser beam welding. The laser beam welding is rendered more effective by combination with the wavy surface region for distributing stresses against stress concentration. In as much as the interfitting surfaces of the pulley disk and the tubular shaft are joined to each other by laser beam welding, the time required to weld the pulley disk and the tubular shaft is shortened, any subsequent step of removing thermal strains from the pulley disk and the tubular shaft is dispensed with, and the pulley disk and the tubular shaft are joined to each other with a sufficient level of strength. Accordingly the present invention provides a method of manufacturing a member of a V-belt pulley, comprising the steps of pressing a pulley disk having a central fitting hole defined therein and spreading outwardly and having a transmission web with a side thereof for contact with a V belt, forging or forging and machining a tubular shaft to a completed shape, pressfitting said tubular shaft into said central fitting hole, integrally joining inter fitting surfaces of said tubular shaft and said pulley disk by laser beam welding, and surface-treating said tubular shaft and said pulley disk which have been joined to each other. According to still another aspect of the present invention, there is provided a method of manufacturing a member of a V-belt pulley, comprising the steps of pressing a pulley disk having a central fitting hole defined therein and spreading outwardly and including a transmission web with a side thereof for contact with a V belt, forging a tubular shaft, machining the tubular shatt on inner and outer edges thereof, processing the tubular shaft by high-frequency induction hardening, grinding the tubular shaft to a completed shape, then press-fitting the tubular shaft into the central fitting hole, integrally joining interfitting surfaces of the tubular shaft and the pulley disk by laser beam welding, and surface-treating the tubular shaft and the pulley disk which have been joined to each other. According to yet still another aspect of the present invention, there is provided a method of manufacturing a member of a V-belt pulley, comprising the steps of pressing a pulley disk having a central fitting hole defined therein and spreading outwardly and including a transmission web with a side thereof for contact with a V belt, forging a tubular shaft, machining the tubular shaft on inner and outer edges thereof to a completed shape, then press-fitting the tubular shaft into the central fitting hole, integrally joining interfitting surfaces of the tubular shaft and the pulley disk by laser beam welding, and surface-treating the tubular shaft and the pulley disk which have been joined to each other. FIG. 1 is a cross-sectional view of a continuously variable transmission for a scooter; FIG. 2(A) is a cross-sectional view illustrative of a laser beam welding process for welding a member of a drive pulley according to the present invention; FIG. 2(B) is a cross-sectional view illustrative of a conventional plasma arc welding process for welding a member of a drive pulley; FIG. 3(A) is a cross-sectional view illustrative of a laser beam welding process for welding a member of a driven pulley according to the present invention; FIG. 3(B) is a cross-sectional view illustrative of conventional plasma arc welding and silver alloy brazing processes for welding a member of a driven pulley; FIG. 4(A) is a cross-sectional view illustrative of a laser beam welding process for welding a member of a movable driven pulley according to the present invention; FIG. 4(B) is a cross-sectional view illustrative of a conventional plasma arc welding process for welding a member of a movable driven pulley; FIG. 5(A) is a flowchart of a process of manufacturing a member of a drive pulley according to the present invention; FIG. 5(B) is a flowchart of a conventional process of manufacturing a member of a drive pulley; FIG. 6(A) is a flowchart of a process of manufacturing a member of a driven pulley according to the present invention; FIG. 6(B) is a flowchart of a conventional process of manufacturing a member of a driven pulley; FIG. 7(A) is a flowchart of a process of manufacturing a member of a movable driven pulley according to the present invention; FIG. 7(B) is a flowchart of a conventional process of manufacturing a member of a movable driven pulley; FIG. 8(A) is a fragmentary perspective view of a member of a driven pulley according to another embodiment of the present invention; FIG. 8(B) is a plan view of the member of the driven pulley shown in FIG. 8(A); FIG. 9(A) is a fragmentary perspective view showing how localized stresses are developed under a load applied to a conventional member of a driven pulley; and FIG. 9(B) is a plan view of the conventional member of the driven pulley shown in FIG. 9(A). As shown in FIG. 1, a continuously variable transmission for a scooter comprises a drive pulley 1 mounted on an end of a crankshaft S of an engine, a driven pulley 2 mounted on an end of a clutch shaft C, and a V belt 3 trained around the drive pulley 1 and the driven pulley 2. The drive pulley 1 comprises two members la, lb, with the member ID Being movaoie towara ana away irom tne member ia along the axis of the crankshaft S. The driven pulley 2 comprises two members 2a, 2b, with the member 2b being movable toward and away from the member 2a along the axis of the clutch shaft C. The V belt 3 is wedged between the members la, lb of the drive pulley 1 and the members 2a, 2b of the driven pulley 2. When the distance between the members la, lb of the drive pulley 1 and the distance between the members 2a, 2b of the driven pulley 2 are varied, the radially wedged position of the V belt 3 between the members la, lb and 2a, 2b is varied to change the speed reduction ratio of the continuously variable transmission. As shown in FIG. 2(A), the member la of the drive pulley 1 comprises a disk-shaped drive face 4 serving as a pulley disk having a central fitting hole 4a defined therein and spreading outwardly and including a transmission web 4b with an inner side thereof held in contact with one side of the V belt 3, and a boss 5 serving as a tubular shaft press-fitted in the central fitting hole 4a and joined to the drive face 4. As shown in FIG. 3(A), the member 2a of the driven pulley 2 comprises a disk-shaped driven face 6 serving as a pulley disk having a central fitting hole 6a defined therein and spreading outwardly and including a transmission web 6b with an inner side thereof held in contact with the other side of the V belt 3, and a boss 7 serving as a tubular shaft press-fitted in the central fitting hole 6a and joined to the driven face 6. As shown in FIG. 4(A), the member 2b of the driven pulley 2 comprises a disk-shaped movable driven face 8 serving as a pulley disk having a central fitting hole 8a defined therein and spreading outwardly and including a transmission web 8b with an inner side thereof held in contact with the one side of the V belt 3, and a cam 9 serving as a tubular shaft press-fitted in the central fitting hole 8a and joined to the movable driven face 8. The principles of the present invention are applied to the member la of the drive pulley 1, the member 2a of the driven pulley 2, and the member 2b of the driven pulley 2. Details of processes of manufacturing these members la, 2a, 2b will successively be described below in comparison with details of conventional processes of manufacturing pulley members. The conventional process of manufacturing the member la will be described below with reference to FIG. 5(B). As shown in FIG. 5(B), the drive face 4 is pressed to shape and then beveled, and the boss 5 is processed by cold forging and then machined on its outer edge. The boss 5 is then press-fitted into the drive face 4, and the drive face 4 and the boss 5 are joined to each other by a welded bead "b" (see FIG. 2(B)) formed between an outer surface of the transmission web 4b and the boss 5 according to a plasma arc welding process using a filler wire of SUS309L. Thereafter, the boss 5 is cut off at its opposite ends, broached, and carburized to remove thermal strains therefrom. Then, the member la is sent to an inspection process. If large thermal strains remain unremoved from the boss 5, then the boss 5 may need to be cut off at its opposite ends again. The plasma arc welding process requires the boss 5 and the drive face 4 to be heated for a relatively long time of about 30 seconds, and hence it is necessary to remove thermal strains from the boss 5 after the plasma arc welding process. If the boss 5 were cut off at its opposite ends and broached before the plasma arc welding process, then the desired level of dimensional accuracy may not be maintained for the boss 5 because of thermal strains developed in the plasma arc welding process. Therefore, the boss 5 has to be machined after the plasma arc welding process. According to the present invention, as shown in FIG. 5(A), the drive face 4 is pressed to shape, and the boss 5 is processed by cold forging, cut off at its opposite ends, and broached. Thereafter, the boss 5 is press-fitted into the drive face 4, and the drive face 4 and the boss 5 are joined to each other by a welded bead "a" (see FIG. 2(A)) formed between an inner circumferential edge of the drive face 4 and an outer circumferential edge of the boss 5. The laser beam welding process is carried out with a laser output power of 2.5 kW and at a welding speed of 2 m/min. and is completed within about 3 seconds. Therefore, any thermal strains developed in the drive face 4 and the boss 5 are so small that any subsequent process of removing thermal strains from the drive face 4 and the boss 5 may be dispensed with. Thereafter, the drive face 4 and the boss 5 are carburized, and then delivered to an inspection process. As described above, the machining steps including the cold forging of the boss 5, the cutting off of the opposite ends of the boss 5, and the broaching of the boss 5 are carried out prior to the welding process. The machining steps thus carried out prior to the welding process are effective in reducing the number of all steps required to manufacture the member la, and shortening the entire manufacturing process. The above three steps, i.e., the cold forging of the boss 5, the cutting off of the opposite ends of the boss 5, and the broaching of the boss 5, may be combined into a single step of precision forging. The omission of the beveling of the drive face 3 is a result of the step of pressing the drive face 4, and has no direct bearing on the present invention. In the laser beam welding process, a laser beam may be applied parallel to the joined edges or slightly radially inwardly with respect to the joint edges, as indicated by the arrows in FIG. 2(A), for the purposes of preventing the laser beam from melting the end of the boss 5 and imparting less thermal strains to the transmission web 4b. The conventional process of manufacturing the member 2a will be described below with reference to FIG. 6(B). As shown in FIG. 6(B), the driven face 6 is pressed to shape and then machined, and the boss 7 is processed by cold forging and then machined on its outer and inner edges and processed by high-frequency induction hardening. The boss 7 is then press-fitted into the driven face 6, and the driven face 6 and the boss 7 are joined to each other by a welded bead "c" (see FIG. 3(B)) formed between an outer surface of the transmission web 6b and the boss 7 according to a plasma arc welding process, and a weld bead "d" formed between an inner surface of the transmission web 6b and the boss 7 according to a silver alloy brazing process. Thereafter, the boss 7 is machined on its inner edge, i.e., finally finished, and then the driven face 6 and the boss 7 are plated with a hard chromium layer. Subsequently, thermal strains are removed from the member 2a, which is then sent to an inspection process. In the plasma arc welding process and the silver alloy brazing process, the boss 7 and the driven face 6 are subject to repeated heating for a total time of about 36 seconds. Therefore, it is necessary to remove thermal strains from the member 2a, and the boss 7 needs to be machined on its inner edge, i.e., finally finished, after the plasma arc welding process and the silver alloy brazing process. According to the present invention, as shown in FIG. 6(A), the driven face 6 is pressed to shape, and the boss 7 is processed by cold forging, machined on its outer and inner edges, processed by high-frequency induction hardening, and then ground. Thereafter, the boss 7 is press-fitted into the driven face 6, and the driven face 6 and the boss 7 are joined to each other by a welded bead "c" (see FIG. 3(A)) formed between an inner circumferential edge of the driven face 6 and an outer circumferential edge of the boss 7 according to a laser beam welding process. The laser beam welding process is carried out with a laser output power of 2.5 kw and at a welding speed of 2 m/min. and is completed within about 3 seconds. Therefore, any thermal strains developed in the driven face 6 and the boss 7 are so small that any subsequent process of removing thermal strains from the driven face 6 and the boss 7 may be dis- pensea witn. Tnerearter, tne DOSS / is macninea on its inner edge, i.e., precision-finished, if its inner edge has been roughly machined previously, or the boss 7 does not need to be precision-finished if its inner edge has been precision-machined previously. Then, the driven face 6 and the boss 7 are plated with a hard chromium layer, and the member 2a is subsequently sent to an inspection process. The machining steps described above are carried out prior to the welding process, and any step of removing thermal strains is dispensed with. Since the time required to weld the driven face 6 and the boss 7 is short, the productivity of the member 2a is increased. The omission of the machining of the driven face 6 is a result of the step of pressing the driven face 6, and has no direct bearing on the present invention. In the laser beam welding process, a laser beam may be applied parallel to the joined edges or slightly radially outwardly with respect to the joint edges, as indicated by the arrows in FIG. 3(A), for the purpose of increasing the static strength due to a spreading weld bead. The conventional process of manufacturing the member 2b will be described below with reference to FIG. 7(B). As shown in FIG. 7(B), the movable driven face 8 is pressed to shape and then machined, and the cam 9 is processed by cold forging and then machined on its outer edge and roughly machined on its inner edge. The cam 9 is then press-fitted into the movable driven face 8, and the movable driven face 8 and the cam 9 are joined to each other by a welded bead "e" (see FIG. 4(B)) formed between an inner surface of the transmission web 8b and the cam 9 according to a plasma arc welding process using a filler wire of mild steel. Subsequently, the cam 9 is machined on its inner edge, i.e., finally finished, and thermal strains are removed from the member 2b. The member 2b is then processed by gas soft nitriding (GSN) and then sent to an inspection process. Inasmuch as the plasma arc welding process takes a relatively long time of about 20 seconds to carry out, removal of thermal strains from the member 2b is indispensable. Furthermore, the cam 9 needs to be machined on its inner edge, i.e., finally finished, after the plasma arc welding process. According to the present invention, as shown in FIG. 7(A), the movable driven face 8 is pressed to shape, and the cam 9 is processed by cold forging and machined on its outer and inner edges. Thereafter, the cam 9 is press-fitted into the movable driven face 8, and the movable driven face 8 and the cam 9 are joined to each other by a welded bead "e" (see FIG. 4(A)) formed between an inner circumferential edge of the movable driven face 8 and an outer circumferential edge of the cam 9 according to a laser beam welding process. The laser beam welding process is carried out with a laser output power of 2.5 kW and at a welding speed of 2 m/min. and is completed within about 3 seconds. Therefore, any thermal strains developed in the movable driven face 8 and the cam 9 are so small that any subsequent process of removing thermal strains from the movable driven face 8 and the cam 9 may be dispensed with. Thereafter, the cam 9 is machined on its inner edge, i.e., precision-finished, if its inner edge has been roughly machined previously, or the cam 9 does not need to be precision-finished if its inner edge has been precision-machined previously. The member 2b is then processed by gas soft nitriding (GSN) and then sent to an inspection process. The machining steps described above are carried out prior to the welding process, and any step of removing thermal strains is dispensed with. Since the time required to weld the movable driven face 8 and the cam 9 is short, the productivity of the member 2b is increased. The omission of the machining of the movable driven face 8 is a result of the step of pressing the movable driven face 8, and has no direct bearing on the present invention. In the laser beam welding process/ a laser beam may be applied parallel to the joined edges or slightly radially inwardly with respect to the joint edges, as indicated by the arrows in FIG. 4(A), for the purposes of increasing the bonding strength and filling any steps until the end surfaces of the movable driven face 8 and the cam 9 lie flush with each other. The joints welded by the laser beam welding process according to the present invention were tested and measured for strength and strain. The measured values of strength and strain are as follows: The member la of the drive pulley 1 was tested by twisting the boss 5 at a given speed with respect to the drive face 4 which was fixed in position. As with the strength of the joint welded by the conventional plasma arc welding process, the welded joint suffered no failure and hence exhibited a desired level of strength even when the torque applied to the boss 5 reached 41 kgf-m. Strains at four points, 90° spaced apart, on the drive face 4 were measured before and after the drive face 4 and the boss 5 were welded. The measured strains were one third or less of those of the drive face 4 welded by the conventional plasma arc welding process. Therefore, it was confirmed that any thermal strains of the member la produced according to the present invention were small. Samples of the member 2a of the driven pulley 2 which were welded under predetermined laser beam welding conditions were measured for tensile strength. It was confirmed that the base metal, i.e., the driven face 6 or the boss 7, was broken, but the welded joint was not fractured in any of the samples. The laser beam welding process was completed within about 3 seconds. It was proven that the welded member 2a had a sufficient level of strength and suffered reduced thermal strains. Strains at four points, 90° spaced apart, on the driven faces 6 of the samples were measured before and after the driven faces 6 and the bosses 7 were welded. It was confirmed that the measured strains were one third or less of those of the drive face 4 welded by the conventional plasma arc welding process. Samples of the member 2b of the movable driven pulley 2 which were welded under laser beam welding conditions, which were varied in a given range, were measured for tensile strength. In any of the samples, the welded joint was not fractured, but the base metal, i.e., the movable driven face 8 or the cam 9, was broken. Strains at four points, 900 spaced apart, on the movable driven faces 8 of the samples were measured before and after the movable driven faces 8 and the cams 9 were welded. It was confirmed that the measured strains were one third or less of those of the movable drive face 8 welded by the conventional plasma arc welding process. It has been understood from the above results that the strengths of the welded members la, 2a, 2b according to the present invention are comparable to the strengths of the conventional welded members la, 2a, 2b, and the strains of the welded members la, 2a, 2b according to the present invention are much smaller than the strains of the conventional welded members la, 2a, 2b. A member 2a of a driven pulley 2 according to another embodiment of the present invention will be described below with reference to FIGS. 8(A) and 8(B). As shown in FIGS. 8(A) and 8(B), the member 2a comprises a driven face 6 including a wavy surface region "g" extending radially from a fitting surface "f' which is fitted over a boss 7. The wavy surface region "g" comprises an annular ridge "gl" contiguous to the fitting surface "f' and projecting axially toward a face side of a transmission web 6b, and an annular groove "g2" contiguous to the annular ridge "gl" at the radially inner end thereof and to the transmission web 6b at the radially outer end thereof. The wavy surface region "g" has a radial cross-sectional shape in the form of an "S", which is shown as an inverted S shape in FIG. 8(A). The wavy surface region "g" serves as a rigid region in the driven face 6. When a load W iis applied to a point P on the transmission web 6b by the V belt 3, stresses are developed in an area "Y" (see FIG. 8(B)) which spreads widely in a crescent pattern within the wavy surface region "g". The wavy surface region "g" is thus effective to prevent undue stresses from concentrating on a localized area. The fitting surface "f" is welded to the boss 7 by a laser beam which is applied substantially axially from behind the transmission web 6b. With the laser beam thus applied, a weld beam having a wedge shape is formed in the fitting surface "f". A durability test was conducted on the member 2a with the wavy surface region "g". As a result of the durability test, it was confirmed that the member 2a with the wavy surface region "g" was more durable than the member 2a with no such wavy surface region "g". WE CLAIM: 1. A method of manufacturing a member of a V-belt pulley, comprising the steps of pressing a pulley disk having a central fitting hole defined therein and spreading outwardly and having a transmission web with a side thereof for contact with a V belt, forging or forging and machining a tubular shaft to a completed shape, pressfitting said tubular shaft into said central fitting hole, integrally joining inter fitting surfaces of said tubular shaft and said pulley disk by laser beam welding, and surface-treating said tubular shaft and said pulley disk which have been joined to each other. 2. A method of manufacturing a member of a V-belt pulley, comprising the steps of pressing a pulley disk having a central fitting hole defined therein and spreading outwardly and having a transmission web with a side thereof for contact with a V belt, and obtaining a tubular shaft for fitting in said central fitting hole by forging or forging and successive machining, said tubular shaft having a completed shape, and integrally welding interfitting surfaces of said tubular shaft and said pulley disk by a laser beam. 3. A method of manufacturing a member of a V-belt pulley, comprising the steps of pressing a pulley disk having a central fitting hole defined therein and spreading outwardly and having a transmission web with a side thereof for contact with a V belt, and obtaining a tubular shaft for fitting in said central fitting hole by forging, machining on inner and outer edges thereof, processing by high-frequency induction hardening, and grinding the tubular shaft to a completed shape, and integrally welding interfitting surfaces of said tubular shaft and said pulley disk by a laser beam. 4. A method of manufacturing a member of a V-belt pulley, comprising the steps of pressing a pulley disk having a central fitting hole defined therein and spreading outwardly and having a transmission web with a side thereof for contact with a V belt, forging a tubular shaft, machining the tubular shaft on inner and outer edges thereof, processing the tubular shaft by high-frequency induction hardening, grinding the tubular shaft to a completed shape, then press-fitting said tubular shaft into said central fitting hole, integrally joining interfitting surfaces of said tubular shaft and said pulley disk by laser beam welding, and surface-treating said tubular shaft and said pulley disk which have been joined to each other. 5. A method of manufacturing a member of a V-belt pulley, comprising the steps of pressing a pulley disk having a central fitting hole defined therein and spreading outwardly and having a transmission web with a side thereof for contact with a V belt, and obtaining a tubular shaft for fitting in said central fitting hole by forging and machining on inner and outer edges thereof , said tubular shaft having a completed shape, integrally welding interfitting surfaces of said tubular shaft and said pulley disk by a laser beam. 6. A method of manufacturing a member of a V-belt pulley, comprising the steps of pressing a pulley disk having a central fitting hole defined therein and spreading outwardly and having a transmission web with a side thereof for contact with a V belt, forging a tubular shaft, machining the tubular shaft on inner and outer edges thereof to a completed shape, then press-fitting said tubular shaft into said central fitting hole, integrally joining interfitting surfaces of said tubular shaft and said pulley disk by laser beam welding, and surface-treating said tubular shaft and said pulley disk which have been joined to each other. 7. A member of a V-belt pulley manufactured by a method as claimed in any one of the preceding claims. 8. A method of manufacturing a member of a V-belt pulley substantially as herein described with reference to the accompanying drawings.

Documents:

2111-mas-1996-abstract.pdf

2111-mas-1996-claims duplicate.pdf

2111-mas-1996-claims original.pdf

2111-mas-1996-correspondance others.pdf

2111-mas-1996-correspondance po.pdf

2111-mas-1996-description complete duplicate.pdf

2111-mas-1996-description complete original.pdf

2111-mas-1996-drawings.pdf

2111-mas-1996-form 1.pdf

2111-mas-1996-form 26.pdf

2111-mas-1996-form 3.pdf

2111-mas-1996-form 4.pdf