JP2007168048A - Working method of taper surface of part for continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a working method to gradually inwardly reduce compression residual stress of a taper surface of a part of a continuously variable transmission, with the maximum stress acting in the neighborhood of a surface. <P>SOLUTION: The taper surface 3 of the part 2 having a sheave surface with which a metallic belt of the belt driving type continuously variable transmission makes contact is hardened, cut and worked by a cutting tool of cemented carbide, etc. and applied with tape lapping work to carry out finishing work by pressurizing and sliding an abrasive material covered tape 1 on a working surface after the cutting work. Additionally, the taper surface is finished and the tape lapping work is applied so that the compression residual stress between the taper surface and the depth of 30 μm from the taper surface comes to be within a region of -500 MPa to -1,200 MPa. The sliding direction of the working surface is in the rotating direction around a taper central axis 53a, and the working surface oscillates in the rectangular direction of the sliding direction. The abrasive material covered tape is an abrasive material covered polyester tape. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a continuously variable transmission component, and more particularly to a method of processing a belt driven continuously variable transmission component having a sheave surface in contact with a metal belt.

  Conventionally, for example, in Patent Document 1, a pulley is formed by two disks having a tapered sheave surface, and the groove width of the pulley is increased by hydraulic pressure to reduce the rotation radius of a metal belt wound around the pulley. A method of manufacturing a disk for a belt-driven continuously variable transmission that performs speed control to increase the speed ratio and change the speed ratio is described. This one uses a numerically controlled lathe on the sheave surface where the metal belt of the disk comes into contact, and keeps the oil property of the sheave surface constant to a surface roughness of about 0.8 to 0.4 microns concentric with the rotation center of the pulley. The spiral groove portion to be cut is cut, and then the sheave surface of the disk is ground to generate a residual stress by a superfinishing operation. That is, after quenching the surface of the continuously variable transmission part, cutting is performed, and finally superfinishing (lapping) is applied to give a compressive residual stress to the surface of the continuously variable transmission part.

  The super-finishing work of this product is described in the case of lapping. In the lapping work, a grinding tool having a shape that matches the sheave surface of the disc is mounted on the grinding machine, and the sheave surface is ground by this grinding tool. As shown in FIG. 7, the residual stress increases from the surface to the inside as shown in FIG. 7, and reaches a maximum value at a depth of about several tens of μm. Thereafter, the residual stress gradually decreases. Has been.

Regarding the lapping in Patent Document 1, only the above-mentioned degree is described, and it is not clear what kind of lapping machine is concrete. Such a lapping device is considered to correspond to, for example, a superfinishing machine or a lapping machine shown in JIS B 0105. In JIS B 0105, a super-finishing machine is "a machine tool that applies a fine-grained wheel to a rotating workpiece and feeds it in the axial direction while applying minute vibrations in the axial direction to finish the surface of the workpiece." In addition, the lapping machine puts a lapping agent that mixes grains and machining fluid between a tool called a lapping and a workpiece, and slides them while applying pressure to both to finish the work surface of the workpiece smoothly. Machine tools, some of which use a wheel instead of grains and laps. "
Japanese Patent No. 2686973

  By the way, since the parts for continuously variable transmissions are in contact with each other, it is preferable that the compressive residual stress near the surface is maximized. Further, it is desirable that the variation in compressive residual stress is small. However, in the example of Patent Document 1 shown in FIG. 7, the unit of compressive stress is unknown, and it is unknown how much compressive stress can be obtained. Further, it is described qualitatively so that the compressive residual stress is maximized at a depth of several tens of μm from the surface, and the distribution of the compressive residual stress is not desirable as a product. There is no technical disclosure about residual stress before lapping and after cutting.

  Therefore, the inventors measured the residual stress after cutting. The result is shown in FIG. The residual stress after cutting is +400 MPa to −300 MPa on the surface, and there are many variations, and the residual stress is maximum when the depth from the surface is 10 μm to 20 μm. Furthermore, this variation tends to be reflected in the variation after lapping as it is. Further, such variation is not disclosed at all in Patent Document 1.

  In view of such problems, the object of the present invention is to provide a machining method in which the compressive residual stress of the tapered surface of a continuously variable transmission component is maximized near the surface, and further, there is little variation in the compressive residual stress near the surface and the surface. Is to provide.

  As a result of diligent research, the present inventors have found that the maximum value of the compressive residual stress is generated at a depth position of several tens of μm from the surface, as described above, in the processing by the lapping machine corresponding to that described in JIS B 0105. In addition, the residual compressive residual stress after cutting tends to vary, but the abrasive coating tape is pressed and slidably contacted with the machined surface after cutting, and the tape lapping process is used. It was found that by performing the finishing, the compressive residual stress was maximized in the vicinity of the surface, and the variation in the compressive residual stress in the vicinity of the surface was reduced.

  Based on this knowledge, in the present invention, after quenching the taper surface of the part having the sheave surface that the metal belt of the belt-driven continuously variable transmission contacts, a taper using a cutting tool made of cemented carbide or CBN is used. Tape lapping process that forms fine oil grooves to keep the properties of oil constant by cutting the surface, and then presses and slides the abrasive coating tape on the processed surface after the cutting process. The above-mentioned problems have been solved by providing a method for machining a tapered surface of a continuously variable transmission component. In the cutting process, the use of a cutting tool made of a cemented carbide or CBN material can improve machining accuracy, shorten the machining time, and reduce variations in the machined surface.

  Further, the taper surface is finished by the tape lapping process, and the compressive residual stress when the depth from the taper surface and the taper surface is 30 μm can be in the range of −500 MPa to −1200 MPa. Item 2).

  According to a third aspect of the present invention, the sliding contact direction of the processed surface of the tapered surface with respect to the abrasive-coated tape is a rotational direction around the central axis of the taper and oscillates in a direction perpendicular to the sliding contact direction. Preferably. In addition, in the thing of the cited reference 1, it does not describe about giving an oscillation, and the description to mount | wear the grinding machine of the cited reference 1 with the grinding tool of the shape corresponding to the sheave surface of a disk is described. Then, it seems that it is difficult to set it as the structure which gives an oscillation. On the other hand, in this invention, since a tape wrap apparatus is used, oscillation can be given easily. Furthermore, in the invention of claim 4, the abrasive-coated tape is preferably an abrasive-coated polyester tape.

  In the present invention, after the taper surface is quenched, after the taper surface is cut using a cutting tool made of cemented carbide or CBN, tape wrap processing using an abrasive-coated tape is performed, so for a continuously variable transmission In addition to improving the surface roughness of the parts, it was possible to impart compressive residual stress and maximize the compressive residual stress in the vicinity of the surface. Moreover, even when there is a variation in the compressive residual stress after cutting, the variation in the compressive residual stress in the vicinity of the surface can be reduced after the tape lapping process.

  Further, the taper surface is finished, and the compressive residual stress between the taper surface and the depth from the taper surface of 30 μm is in the range of −500 MPa to −1200 MPa, so that the sheave surface of the continuously variable transmission parts is stabilized and worn. , Increased proof stress and extended life.

  Further, according to the invention described in claim 3, since the average and uniformization of the compressive residual stress is further improved by the oscillation, there is less variation in the surface and the depth direction of the compressive residual stress. It became. Furthermore, according to the invention described in claim 4, the amount of polishing and surface roughness can be improved by tape wrapping.

  An example of the best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a front view of a main part in which a workpiece is attached to a tape wrap apparatus for tape wrap processing of the present invention, FIG. 2 is a side view of the main part when viewed from the direction A in FIG. 1, and FIG. The schematic front view which shows the whole structure of the tape part mounting part of a lap | wrap apparatus, (b) is a schematic sectional drawing in alignment with the BB line of (a), For convenience of explanation, each part of a shoe assembly, a cylinder, and a main body is demonstrated. The drive connection relationship is shown in the main part schematic block diagram. FIG. 4 is a schematic side view with a part cut away when viewed from the A direction of FIG.

  As shown in FIGS. 1 to 4, the tape wrap apparatus includes a relatively incompressible abrasive-coated tape 1 and a tape 1 abrasive-coated surface on a workpiece (a metal belt of a belt-driven continuously variable transmission). A shoe assembly 5 having a relatively rigid tip surface 4 that contacts and presses against the tapered surface 3 of the component 2, and a moving device 11 that is supported by the body 6 and reciprocates the shoe assembly. It is composed of The distal end surface 4 of the shoe assembly 5 has two holes 35, 35 '(three or more) at positions spaced apart in the radial direction of the surface 2 of the workpiece 2 that is a processed surface to be rotated provided on the shoe assembly 5. These holes may be supported by pistons 36 and 36 'biased by springs 37 and 37' inserted into the holes, respectively. The workpiece 2 includes a head center 52 rotatably supported by a head stock (not shown) attached to a main body 6 attached to a tape wrap device (not shown), and a tail rotatably supported by a tail stock 50. Centered by the center 51 and rotated around the rotation shaft 53a (arrow 53).

  The tip surface 4 of the shoe assembly 5 has two holes 35 and 35 '(three or more holes may be spaced apart) in the radial direction with respect to the surface 2 of the workpiece 2 that is a processed surface to be rotated. The inner peripheral portion 39 and the outer peripheral portion 40 are supported by the pistons 36 and 36 ′ biased by the springs 37 and 37 ′ inserted into the inner peripheral portion 39 and the outer peripheral portion 40 regardless of the peripheral speed between the inner peripheral portion 39 and the outer peripheral portion 40. Thus, the pressure applied to the surface of the processing surface of the abrasive-coated tape is uniformly controlled so that it can be efficiently finished to a uniform surface.

  The abrasive-coated tape 1 was a relatively incompressible abrasive-coated tape. Here, an abrasive-coated polyester tape was used. In addition, as the shoe assembly 5 having a relatively rigid front end surface that presses the tape in contact with the surface 3 of the workpiece 2, the rigid surface has a hardness exceeding the value of 90 durometer A and is precisely machined honing. It is preferable to provide a shoe assembly 5 having a tip surface 4 using an insert stone made of a grinding stone material. The processing surface 3 is a tapered surface, but may be a flat surface.

  As shown in FIGS. 3A, 3B, and 4, the tape loading device of the tape wrap device includes a tape supply holder 7, a tape take-up holder 8, and a shoe assembly 5 supported by the main body 6, respectively. A moving device 11 that reciprocates and a moving shaft 10 that is supported by the main body 6 so as to be movable in the axial direction and that is pressed by the spring 10b and abuts against the shoe assembly end portion 5 ′ are provided, and the shoe assembly 5 moves. When moving forward by the device 11, the relatively rigid tip surface 4 of the shoe assembly 5 is pressed against the surface 3 of the workpiece 2 via the abrasive coating tape 1, and the shoe assembly 5 is moved by the moving device 11. , The moving shaft 10 is pushed by the shoe assembly end 5 ′ and moves against the spring 10b, and the first spline 12 and the second spline 13 ( First gear meshing with FIG. 4 and the second gear 15 (FIG. 4), the tape feed shafts 43a and 43b and the tape take-up holder 8 are respectively rotated, and the tape feed shafts 43a and 43b are coated with an abrasive material of a predetermined length. After the tape 1 is wound, it is wound on the tape winding holder 8.

  As shown in FIGS. 1A and 1B, the moving device 11 is a cylinder, a cylinder support 111 that supports the cylinder 11 is fixed to the main body 6, and the end of the cylinder rod 11a of the cylinder 11 is a shoe assembly. The shoe assembly 5 is reciprocally moved by a cylinder rod 11a on guide slides 9 and 9 supported in slide holes 9 'and 9' provided in the cylinder support 111 so as to be reciprocally movable. . When the piston 11b of the cylinder 11 receives air pressure from a pneumatic device (not shown) and advances to a position indicated by 11b ', the distal end surface 4 of the shoe assembly 5 advances to the 4' position in the y direction, and the distal end surface 4 ' Presses the surface 3 of the workpiece 2 through the tape 1, and the surface 3 of the workpiece 2 is microfinished with the abrasive coating tape 1 very precisely. As shown in FIG. 3 (b), the cylinder support 111 is mounted together with the shoe assembly 5 on the oscillation slide 22 of the linear slide 21 fixed to the main body 6, and the tip end surface 4 of the shoe assembly 5 is laterally moved. An oscillation connecting rod 21 of the oscillation device 20 that reciprocates in the x direction is connected to the cylinder support 111, and the oscillation slide 23 of the linear slide 22 and the cylinder support are connected via the oscillation connecting rod 21. 111, the cylinder 11 and the shoe assembly 5 as a whole are caused to oscillate in the direction of the rotation axis (x) (in a direction perpendicular to the sliding contact direction of the front end surface 4 slidably contacting the surface 3).

  A tape wrap shown in FIG. 1 to FIG. 4 is a continuously variable transmission component having a taper surface 3 cut by using a cutting tool made of CBN after quenching the tapered surface 3 of the component 2 of the continuously variable transmission. It was attached to the apparatus, and the abrasive coating tape 1 was oscillated while being pressed and slidably contacted with the taper surface 3 for finishing. FIG. 5 is a diagram showing the relationship between the compressive residual stress of the taper surface after cutting and the depth from the surface according to the present invention, and FIG. 6 shows the compressive residual stress and surface of the taper surface after tape wrap processing of the present invention. It is a figure which shows the relationship of the depth from. As shown in FIG. 5, the compressive residual stress of the tapered surface after cutting is about +400 MPa to −300 MPa on the tapered surface, and has a maximum value of about −900 to −1100 MPa at a depth of about 10 μm to 20 μm, After that, it gradually decreases as the depth increases. Further, the surface is subjected to + residual stress, that is, tensile residual stress, and remarkably reduces the strength in the vicinity of the tapered surface.

  On the other hand, as shown in FIG. 6, the taper surface after the tape lapping process of the present invention is about −600 MPa to −1100 MPa between the taper surface and 30 μm from the taper surface, which is higher compressive residual stress than after the cutting process. Thus, the variation is small, and the maximum compressive residual stress is shown in the vicinity of the surface. Further, in the position deeper than 30 μm, the residual stress after cutting in FIG. 5 is almost the same. In the tape wrap processing of the present invention, surface modification is performed up to a depth of about 30 μm, and the effect is deeper at deeper positions. It can be said that there are few. On the other hand, although the unit is unknown in the conventional patent document 1, there is a difference in residual stress even at a deep position of 100 or 200 μm as compared with the case of grinding. From this point of view, the lapping process of Patent Document 1 is influenced to a considerably deep position, and can be said to be completely different from the action and effect of the tape lapping process of the present invention.

  As described above, according to the processing method of the present invention, the compressive residual stress on the taper surface can be increased after cutting, the variation in the compressive residual stress in the vicinity of the taper surface is reduced, and the maximum compressive residual stress in the vicinity of the surface is obtained. It can be seen that the stress is shown and then gradually decreases with increasing depth, resulting in a uniform and stable distribution. Accordingly, since the stress gradient is small, it is possible to provide a long-life component with less occurrence of internal cracks and the like.

  In the embodiment of the present invention, tape wrap processing is performed after cutting, but after finishing the surface roughness by paper wrap, polishing, etc. to the extent that the residual stress after cutting does not change significantly, final finishing is performed. The tape lapping process of the present invention that gives residual stress may be applied.

It is the principal part front view which attached the to-be-processed object to the tape wrap apparatus for performing the tape wrap process of this invention. It is a principal part side view seen from the A direction of FIG. (A) is a schematic front view which shows the whole structure of the tape part mounting part of a tape wrap apparatus, (b) is a schematic sectional drawing in alignment with the BB line of (a), For convenience of explanation, a shoe assembly, a cylinder, and The drive connection relationship of each part of a main body is shown with a principal part schematic block diagram. It is the schematic side view which notched a part seeing from the A direction of Fig.3 (a). It is a figure which shows the relationship between the compression residual stress of the taper surface after the cutting after the cutting of this invention, and the depth from the surface. It is a figure which shows the relationship between the compression residual stress of the taper surface after the tape lapping process of this invention, and the depth from the surface. It is a figure which shows the relationship between the compression residual stress of the taper surface after the conventional lapping, and the depth from the surface.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Abrasive-coated tape 2 Part which has sheave surface which metal belt of belt drive type continuously variable transmission contacts 3 Tapered surface 53a Tapered central axis (rotating shaft)

Claims (4)

After quenching the taper surface of the part with the sheave surface that the metal belt of the belt-driven continuously variable transmission contacts, the properties of the oil are obtained by cutting the taper surface using a cutting tool made of cemented carbide or CBN. A continuously variable transmission characterized in that after forming a minute oil groove to keep constant, a tape lapping process is performed for finishing by pressing and sliding the abrasive coating tape on the processed surface after the cutting process. Machining method of taper surface of machine parts.   Tape wrap processing is performed so that the taper surface is finished by the tape wrap processing, and the compressive residual stress between the taper surface and the depth from the taper surface is within a range of −500 MPa to −1200 MPa. The method for processing a tapered surface of a continuously variable transmission component according to claim 1, wherein the taper surface is processed. The sliding contact direction of the processing surface of the tapered surface with respect to the abrasive coating tape is a rotation direction around a taper central axis, and is oscillated in a direction perpendicular to the sliding contact direction. A method for machining a tapered surface of a continuously variable transmission part according to 1 or 2. 4. The method for processing a tapered surface of a continuously variable transmission component according to claim 1, wherein the abrasive-coated tape is an abrasive-coated polyester tape.

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