CN108693744B - Method and apparatus for manufacturing magnetic roller - Google Patents

Abstract

The invention provides a method and an apparatus for manufacturing a magnetic roller, which can restrain deformation of a sleeve and can firmly fix the sleeve and a flange. When both ends of the sleeve are fixed to the flanges, the rollers (16) of one set of three are brought into contact with both ends of the sleeve so that the outer peripheral surfaces of the rollers (16) of one set of three are inclined with respect to the center axis of the magnetic roller, i.e., the material to be caulked (11), and the rollers (16) are moved in the axial direction of the magnetic roller, i.e., the material to be caulked (11), i.e., in the direction of the arrow a while the rollers (16) are rotated in the direction of the arrow b, and the sleeve is caulked, thereby fixing the sleeve and the flanges.

Description

Method and apparatus for manufacturing magnetic roller

Technical Field

The present invention relates to a method and an apparatus for manufacturing a magnetic roller used for transporting a magnetic developer or the like.

Background

In electrophotographic apparatuses, electrostatic recording apparatuses, and the like, magnetic rollers are used as means for conveying a magnetic developer, that is, for example, a developing roller and a cleaning roller. The magnetic roller is formed as follows: a magnet member having a plurality of magnetic poles is disposed inside a sleeve of a non-magnetic body, and the magnet member and the sleeve are relatively rotated. Further, various magnetic rollers and methods for manufacturing the same have been proposed (patent document 1: Japanese patent application laid-open No. 2-205874; patent document 2: Japanese patent application laid-open No. 6-202479; patent document 3: Japanese patent application laid-open No. 11-84879, etc.).

For example, a magnetic roller disclosed by patent document 1 includes: a magnet member having a plurality of magnetic poles extending in an axial direction on an outer peripheral surface thereof; a hollow cylindrical sleeve formed of a plastically deformable nonmagnetic material; and flanges provided at both ends of the sleeve and fixed to the sleeve. By fixing the sleeve and the flange, the magnet member and the sleeve can be relatively rotated.

The fixation of the sleeve and the flange as described above can be performed by a mechanical method in patent documents 1 and 3, or can be performed by a chemical method in patent document 2.

Specifically, in patent document 1, a flange is fitted into an annular recess provided in an inner surface of an end portion of a sleeve, and the end portion of the sleeve is bent, thereby mechanically fixing the sleeve and the flange. In patent document 3, the sleeve and the flange are mechanically fixed by bending and deforming the end portion of the sleeve toward the end portion of the flange by a die provided in a pressing device, and caulking and fixing the flange and the sleeve.

In contrast, in patent document 2, after an adhesive is injected into an annular groove provided in a flange, a sleeve is inserted into the flange, whereby the sleeve and the flange are fixed by the adhesive force of the adhesive.

Disclosure of Invention

In the case of fixing with an adhesive as disclosed in patent document 2, dimensional accuracy is good because no mechanical force is applied, but since it takes a long time to complete adhesion, production efficiency cannot be improved.

The fixing method disclosed in patent document 3 can shorten the process compared to the adhesion method. However, since the sleeve is caulked by a method of applying a pressure in a short time in the axial direction of the flange, it is impossible to avoid a reduction in the deflection accuracy accompanying the deformation of the sleeve and a reduction in the dimensional accuracy caused by the expansion of the sleeve itself. Further, in order to increase the caulking strength, it is necessary to apply a strong pressure in the axial direction, and when the shaft of the entire metal mold is inclined with respect to the shaft of the sleeve, a portion having a high caulking strength and a portion having a low caulking strength are mixed, and therefore, there is a possibility that the dimensional accuracy of the magnet roller itself is lowered. In view of the above, the fixing method of patent document 3 has the following problems: it cannot be applied to a magnetic roller requiring high dimensional accuracy.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method and an apparatus for manufacturing a magnetic roller, which can suppress deformation of a sleeve and can also firmly fix the sleeve and a flange.

The method for manufacturing a magnetic roller according to the present invention is a method for manufacturing a magnetic roller, the method comprising: a sleeve which is a cylindrical non-magnetic body; a magnet disposed inside the sleeve and having a plurality of magnetic poles arranged in a circumferential direction; and flanges to which both ends of the sleeve are fixed, wherein the sleeve is crimped while moving the rollers in the axial direction of the magnetic rollers by bringing the rollers in one set into contact with both ends of the sleeve so that the outer peripheral surfaces of the rollers in the other set are inclined with respect to the central axis of the magnetic rollers when the sleeve is fixed to the flanges. The term "simultaneously" as used herein means that the roller is rotated at a point of time when the roller is moved in the axial direction of the magnetic roller and is brought into contact with both end portions of the sleeve.

In the method of manufacturing a magnetic roller according to the present invention, the roller surface of a set of three rollers is inclined and brought into contact with the respective two ends of the sleeve, and the roller is moved in the axial direction of the magnetic roller while rotating the roller, and is caulked to the sleeve, whereby the two ends of the sleeve are fixed to the flanges. Therefore, since the sleeve and the flange are fixed by the caulking process, an adhesive is not required and the cost is low, and the time required for the fixing process is short. Further, the problem of caulking, which is poor in deflection accuracy and is likely to cause deformation (expansion) of the sleeve, can be solved. That is, the load on the sleeve at the time of caulking is small, and deflection of the sleeve and deformation (expansion) of the sleeve are also small. Further, by the operation of moving the roller in the axial direction of the magnetic roller while the roller is rotating, the load on the sleeve is reduced, and the magnetic roller can be manufactured.

The method for manufacturing a magnetic roller according to the present invention is characterized in that the rotational direction of the triplet roller in contact with one end of the sleeve is opposite to the rotational direction of the triplet roller in contact with the other end of the sleeve.

In the method for manufacturing a magnetic roller according to the present invention, the rollers in a set of three which are in contact with one end portion of the sleeve and the rollers in a set of three which are in contact with the other end portion of the sleeve are set so that the rotation directions are opposite to each other. Therefore, deformation (expansion) of the sleeve center portion can be suppressed.

The method for manufacturing a magnetic roller according to the present invention is characterized in that the outer circumferential surface of the roller has: an inclined surface that expands from a front end surface to a rear end surface; and an inner arc surface arranged on a rear end face side of the inclined surface.

In the method for manufacturing a magnetic roller according to the present invention, a roller having an outer peripheral surface (a processed surface) including: an inclined surface expanding from the front end surface to the rear end surface; and an inner arc surface provided on the rear end surface side of the inclined surface. Therefore, since the end portion of the sleeve can be efficiently caulked and further bitten into the flange, a firm fixation is obtained.

The method of manufacturing a magnetic roller of the present invention is characterized in that the inner arcuate surface of the roller is brought into contact with the end portion of the sleeve at the end of moving the roller in the axial direction of the magnetic roller.

In the method of manufacturing a magnetic roller of the present invention, the inner arcuate surface of the roller is brought into contact with the end portion of the sleeve in the final process of moving the roller in the axial direction of the magnetic roller. Therefore, the end portion of the sleeve can be more firmly bitten into the flange.

In the method for manufacturing a magnetic roller according to the present invention, the center axis of the roller is inclined with respect to the center axis of the magnetic roller.

In the method for manufacturing a magnetic roller of the present invention, the center axis of the roller is inclined with respect to the center axis of the magnetic roller, and a cylindrical body (top cover) for mold release is easily arranged in the central space of the roller in a set of three rollers.

The present invention is characterized in that the outer circumferential surface of the roller has: a horizontal plane that expands from a front end surface to a rear end surface; and an inner arc surface that is disposed on the rear end surface side of the horizontal plane and that inclines the center axis of the roller with respect to the center axis of the magnetic roller.

In the method for manufacturing a magnetic roller according to the present invention, even when a roller having no inclined surface on the outer peripheral surface is used, the outer peripheral surface of the roller can be inclined with respect to the central axis of the magnetic roller by inclining the central axis of the roller with respect to the central axis of the magnetic roller.

The manufacturing device of the magnetic roller of the invention is used for manufacturing the magnetic roller, and is characterized in that the magnetic roller comprises: a sleeve which is a cylindrical non-magnetic body; a magnet disposed inside the sleeve and having a plurality of magnetic poles arranged in a circumferential direction; and a flange to which both end portions of the sleeve are fixed, the apparatus including: a caulking machine having three rollers in contact with the end of the sleeve; a rotating portion that rotates the caulking machine; and a moving unit that moves the caulking machine in an axial direction of the magnet rollers, arranges the rollers such that outer peripheral surfaces thereof are inclined with respect to a central axis of the magnet rollers, moves the rollers in the axial direction of the magnet rollers while the rollers rotate, and caulks the sleeve to fix the sleeve and the flange. The term "simultaneously" as used herein means that the roller is rotated at a point of time when the roller is moved in the axial direction of the magnetic roller and is brought into contact with both end portions of the sleeve.

In the present invention, since the sleeve and the flange are fixed by caulking, it is possible to reduce the cost because an adhesive is not required as compared with the bonding process, and it is not necessary to manage the curing of the adhesive, so that it is possible to exert an effect that it is possible to reduce the working space and the processing time. Further, since the load on the sleeve is small at the time of caulking, the amount of deformation of the sleeve is reduced, the deflection accuracy of the sleeve can be improved, and extremely strong fixation can be achieved while suppressing deformation (expansion) of the sleeve.

Drawings

Fig. 1 is a structural view showing a magnet roller.

Fig. 2 is a view showing the shape of the sleeve.

Fig. 3 is a schematic configuration diagram showing an apparatus for caulking according to the first embodiment.

Fig. 4 is a diagram showing an arrangement state of three rollers.

Fig. 5 is a schematic view showing a state where caulking is performed according to the first embodiment.

Fig. 6 is a view showing a sectional shape of the roller according to the first embodiment.

Fig. 7 is a diagram showing a change in deformation of the sleeve during the caulking process.

Fig. 8 is a schematic configuration diagram showing an apparatus for caulking according to a second embodiment.

Fig. 9 is a schematic view showing a state where caulking is performed according to the second embodiment.

Fig. 10 is a view showing a cross-sectional shape of a roller according to a first example of the second embodiment.

Fig. 11 is a view showing a cross-sectional shape of a roller of a second example of the second embodiment.

Fig. 12 is a schematic view showing a caulking force applied to a sleeve by a conventional caulking method.

Fig. 13 is a schematic view showing a caulking force applied to a sleeve by the caulking method of the present invention.

Fig. 14 is a graph showing the measurement results of the sleeve deflection in the present invention example and the comparative example.

Fig. 15 is a graph showing the results of measuring the outer diameter of the sleeve in the present invention example and the comparative example.

Fig. 16 is a graph showing the measurement results of the fixing strength in the rotation direction of the flange in the present invention example and the comparative example.

Detailed Description

The present invention will be described in detail below with reference to the drawings showing embodiments of the present invention.

Fig. 1 shows a structure of a magnet roller, fig. 1A is a longitudinal sectional view of the magnet roller, and fig. 1B is a cross-sectional view taken along line a-a of fig. 1A. The magnetic roller 1 has: a cylindrical sleeve 2 made of a non-magnetic material; a magnet member 3 disposed inside the sleeve 2; and flanges 4, 4 fixed to the inner sides of both ends in the longitudinal direction of the sleeve 2.

The sleeve 2 is made of a nonmagnetic metal material such as an aluminum alloy or nonmagnetic stainless steel. The magnet member 3 is configured such that a shaft 6 having a circular rod shape is inserted and fixed into a center hole of a magnet 5 having a cylindrical shape, and the magnet 5 includes a plurality of magnetic poles arranged in a circumferential direction. The shaft 6 is made of a high-strength material such as metal, and is integrated with the magnet 5.

The flanges 4, 4 are made of a nonmagnetic metal material such as an aluminum alloy or nonmagnetic stainless steel. Knurls 40 (grooves formed at equal intervals on the outer peripheral surface, plain knurls) are formed on the outer peripheral surface of each flange 4, and the outer edge portion of each flange 4 is not chamfered. Bearings 7, 7 are embedded and mounted inside the flanges 4, 4. These bearings 7 and 7 support the shaft 6. With this structure, the sleeve 2 and the magnet member 3 can be relatively rotated. Further, as for the knurling 40, a cross-hatched knurling may also be applied. The materials (non-magnetic metal materials) used for the sleeve 2 and the flange 4 may be appropriately set in consideration of the hardness and the like of the metals used in the respective materials in order to exert the effect of the present invention.

Fig. 2 shows the shape of the sleeve 2, fig. 2A is a plan view of the sleeve 2, and fig. 2B is a cross-sectional view taken along line B-B of fig. 2A. A plurality of grooves 20 extending in the axial direction are formed at predetermined intervals on the outer peripheral surface of the sleeve 2. The sleeve 2 is disposed in parallel with a photosensitive drum (not shown), and toner held by the outer periphery of the sleeve 2 is conveyed to and adhered to an electrostatic latent image of a developing portion of the photosensitive drum. In this case, the plurality of grooves 20 are provided to improve the magnetic developer conveyance performance. Instead of the grooves 20, the surface of the sleeve 2 may be provided with projections and recesses, and the surface of the sleeve 2 may be roughened by sandblasting. Alternatively, surface treatment or the like for improving transportability may be performed.

The manufacturing process of the magnetic roller 1 having such a structure will be briefly described.

The magnet part 3 is first manufactured. For example, the magnet member 3 may be manufactured by integrating the shaft 6 with a center hole of a cylindrical magnet 5 using an adhesive, the magnet 5 including a plurality of magnetic poles arranged in the circumferential direction. Further, a round bar as the shaft 6 is set in a metal mold of a compression molding apparatus, and a magnetic composition in which magnetic powder and resin are mixed is supplied to the periphery of the round bar, and is pressure molded and integrated, and then a plurality of magnetic poles are magnetized in the circumferential direction of the magnet 5, thereby manufacturing the magnet member 3.

Next, the flanges 4 and 4 are fitted to both end portions of the shaft 6 of the manufactured magnet component 3 via the bearings 7 and 7. Finally, the flanged magnet member 3 is inserted into the sleeve 2, and the flanges 4 and 4 are fixed to both end portions of the sleeve 2 by caulking as described below.

Next, the caulking process for fixing the sleeve 2 and the flanges 4 and 4, which are features of the present invention, will be described in detail in a first embodiment (a mode in which the center axis of the roller 16 is parallel to the center axis of the magnetic roller 1) and a second embodiment (a mode in which the center axis of the roller 16 is inclined with respect to the center axis of the magnetic roller 1).

(first embodiment)

Fig. 3 is a schematic configuration diagram showing an apparatus for caulking according to the first embodiment. In fig. 3, reference numeral 10 denotes a base, 11 denotes a caulking target, and the caulking material is the flanged magnet member 3 inserted into the sleeve 2.

A support table 12 for supporting the material to be caulked 11 is provided on the base 10, and a jig 13 is provided above the support table 12 so as to clamp the center portion of the material to be caulked 11 between the jig 13 and the support table 12. The support table 12 includes: an adjusting mechanism (not shown) for adjusting the position of the material to be caulked 11 on the base 10. The jig 13 is movable up and down, and abuts against the material to be caulked 11 during caulking to fix the material to be caulked 11.

Further, two caulking machine mounting tables 18, 18 separated by an appropriate distance are placed on the base 10. Caulking machines 14, 14 are mounted on the inner side surfaces of the caulking machine mounting tables 18, 18. Each caulking machine 14 has the same structure, and has a structure in which three caulking rollers 16, 16 are mounted on a roller base 15. Fig. 4 is a view showing the arrangement state of the three rollers 16, and as shown in fig. 4, the three rollers 16, 16 arranged at a phase angle of 120 ° in the circumferential direction are provided on the roller bed 15. The central axis of each roller 16 is parallel to the central axis of the material to be caulked 11. A cylindrical body 17 for mold release is provided at a position surrounded by the three rollers 16, 16 in the roller base 15.

Each of the roller bases 15 is connected to a rotating machine 19 via a caulking machine mounting table 18, and the caulking machine 14 is rotated by driving the rotating machine 19. Further, the horizontal movement machine 21 is connected to each caulking machine mounting table 18, and the caulking machine mounting table 18 (and the caulking machine 14) is horizontally moved in the axial direction of the material to be caulked 11 by driving of the horizontal movement machine 21.

Fig. 5 is a schematic view showing a state where caulking is performed according to the first embodiment. In fig. 5, the same portions as those in fig. 3 are denoted by the same reference numerals. By the above-described driving structure (the rotating machine 19 and the horizontal moving machine 21), the roller 16 can perform a rotational movement about the axial center of the material to be caulked 11 and a horizontal movement in the axial direction (the left-right direction in fig. 5) of the material to be caulked 11. During the caulking process, the two caulking machines 14 and 14 linearly move in a direction toward the center of the material 11 to be caulked (see arrow a in fig. 5) and rotationally move in opposite directions (opposite directions) (see arrow b in fig. 5). Further, the rotational movement in the opposite direction (reverse direction) means that the two caulking machines 14, 14 in fig. 5 rotate to squeeze (twist) the material to be caulked 11, for example, the caulking machine 14 on the left side rotates clockwise as viewed from the side on the left side in fig. 5; the caulking machine 14 on the right side also rotates clockwise when viewed from the side on the right side. By the movement of the two caulking machines 14, 14 in this manner, the one-side triple rollers 16, 16 and the other-side triple rollers 16, 16 rotate in opposite directions to each other and move in a direction toward the center of the material to be caulked 11 during caulking. In the caulking process, the center portion of the material to be caulked 11 is supported and fixed by being sandwiched between the support table 12 and the jig 13. Here, "simultaneously" means that the rollers 16, 16 are moved in the horizontal direction and rotated at the time point of contact with the material to be caulked 11. In other words, the rolls 16, 16 can be moved in a direction toward the center side of the material 11 to be caulked while being rotated. That is, the rotation or the movement to the center side may be started before the rollers 16, 16 come into contact with the material to be caulked 11.

Each roller 16 has the same shape, and its sectional shape is shown in fig. 6. The outer peripheral surface (working surface) 16a of the roller 16, which contacts the sleeve 2, has: an inclined surface 16b expanding from the front end surface to the rear end surface; and an inner arc surface 16c provided on the rear end surface side of the inclined surface 16 b. By having the inclined surface 16b, the outer peripheral surface (machined surface) 16a is inclined with respect to the central axis of the material to be caulked 11 (magnet roller 1), and the roller 16 is brought into contact with the sleeve 2. The outer peripheral surface (machined surface) 16a of each rotating roller 16 contacts the end of the sleeve 2, presses the end of the sleeve 2, and caulks the end to fix the sleeve 2 and the flange 4.

Fig. 7 is a diagram showing a change in deformation of the sleeve 2 in the caulking process. Fig. 7A shows a state before caulking, in which the undeformed sleeve 2 is in contact with the flange 4. In fig. 7, the knurls 40 are not shown.

Fig. 7B shows a state in the first half of the caulking process, in which the inclined surface 16B of the outer peripheral surface 16a of the roller 16 abuts on the sleeve 2. In fig. 7B, the length of the arrow indicates: the amount of force applied to the end of the sleeve 2. The force applied in the radial direction of the sleeve 2 (arrow d) is larger than the force applied in the axial direction of the sleeve 2 (arrow e), thereby slightly bending the end of the sleeve 2. By adjusting the shape (inclination angle) of the inclined surface 16b, the magnitude relation of the applied force can be realized.

Fig. 7C shows a state in the latter half (final process) of the caulking process, in which the inner arcuate surface 16C of the outer peripheral surface 16a of the roller 16 abuts against the sleeve 2. In fig. 7C, the length of the arrow indicates: the force applied to the end of the sleeve 2 is larger in the axial direction of the sleeve 2 (arrow f) than in the radial direction of the sleeve 2 (arrow g), so that the end of the sleeve 2 is further bent and bites into the flange 4.

(second embodiment)

Next, a second embodiment in which the center axis of the roller 16 is inclined with respect to the center axis of the magnetic roller 1 will be described. Fig. 8 is a schematic configuration diagram showing an apparatus for performing caulking according to the second embodiment, and fig. 9 is a schematic diagram showing a state in which caulking is performed according to the second embodiment. In fig. 8 and 9, the same reference numerals are given to the same parts as those in fig. 3 and 5.

The second embodiment is similar to the first embodiment in that three rollers 16, 16 shown in fig. 4 and having a phase angle of 120 ° in the circumferential direction are provided on the roller base 15, but is different from the first embodiment in that each roller 16 is provided so as to be inclined outward (in a direction away from the central axis) by θ with respect to the central axis of the material to be caulked 11. The magnitude of θ is, for example, 10 °. Since other configurations are the same as those of the first embodiment, descriptions of the other configurations are omitted.

Since the rollers 16 are disposed such that the central axes thereof are inclined outward from the central axis of the material to be caulked 11 (the magnet rollers 1), the cylindrical body 17 (the top sleeve) for mold release can be easily disposed in the central space of the pair of three rollers 16, as compared with the first embodiment.

In the second embodiment, as in the first embodiment, during the caulking process, the two caulking machines 14 and 14 linearly move in the direction toward the center of the material 11 to be caulked (see arrow a in fig. 9) and rotationally move in the opposite direction (see arrow b in fig. 9), whereby the one-side triple rollers 16, 16 and the other-side triple rollers 16, 16 and 16 rotate in the opposite directions to each other and also move in the direction toward the center of the material 11 to be caulked. Then, the outer peripheral surface (machined surface) 16a of each rotating roller 16 comes into contact with the end portion of the sleeve 2, presses the end portion of the sleeve 2, and caulks the end portion, thereby fixing the sleeve 2 and the flange 4.

Fig. 10 is a diagram showing a cross-sectional shape of the roller 16 according to the first example of the second embodiment. As in the first embodiment, the outer peripheral surface (working surface) 16a of the roller 16 includes: an inclined surface 16b expanding from the front end surface to the rear end surface; and an inner arc surface 16c provided on the rear end surface side of the inclined surface 16 b.

In the first example, during the first half of the caulking process, the inclined surface 16B of the outer peripheral surface 16a of the roller 16 abuts on the sleeve 2 (see fig. 7B). The force applied in the radial direction of the sleeve 2 (arrow d) is larger than the force applied in the axial direction of the sleeve 2 (arrow e), thereby slightly bending the end of the sleeve 2. The magnitude relation of the applied force can be realized by adjusting the inclination angle θ of the roller 16 with respect to the central axis of the material to be caulked 11 and/or the shape (inclination angle) of the inclined surface 16 b. In the second half of the caulking process, the inner arcuate surface 16C of the outer circumferential surface 16a of the roller 16 abuts against the sleeve 2 (see fig. 7C). The force applied in the axial direction of the sleeve 2 (arrow f) is larger than the force applied in the radial direction of the sleeve 2 (arrow g), thereby causing the end of the sleeve 2 to bend further and bite into the flange 4.

Fig. 11 is a diagram showing a cross-sectional shape of a roller 16 of a second example of the second embodiment. Unlike the first embodiment and the first example, the outer peripheral surface (working surface) 16a of the roller 16 has no inclined surface, but includes: a horizontal surface 16d extending from the front end surface to the rear end surface; and an inner arc surface 16c provided on the rear end surface side of the horizontal surface 16 d. In the second example, the roller 16 does not have an inclined surface, but the center axis of the roller 16 is inclined with respect to the center axis of the material to be caulked 11 (the magnetic roller 1), so that the outer peripheral surface (the processed surface) 16a may be inclined with respect to the material to be caulked 11 (the magnetic roller 1) and the roller 16 may be brought into contact with the sleeve 2, as in the first embodiment and the first example.

In the second example, the horizontal surface 16d of the outer peripheral surface 16a of the roller 16 abuts on the sleeve 2 in the first half of the caulking process (see fig. 7B). The force applied in the radial direction of the sleeve 2 (arrow d) is larger than the force applied in the axial direction of the sleeve 2 (arrow e), thereby slightly bending the end of the sleeve 2. The magnitude relation of the applied force can be realized by adjusting the inclination angle θ of the roller 16 with respect to the central axis of the material to be caulked 11. In the second half of the caulking process, the inner arcuate surface 16C of the outer circumferential surface 16a of the roller 16 abuts against the sleeve 2 (see fig. 7C). The force applied in the axial direction of the sleeve 2 (arrow f) is larger than the force applied in the radial direction of the sleeve 2 (arrow g), thereby causing the end of the sleeve 2 to bend further and bite into the flange 4.

Here, a comparison between the caulking method of the present invention (first embodiment and second embodiment) and a caulking method performed in the past will be described.

Fig. 12 is a schematic view showing a caulking force applied to the sleeve 2 by a conventional caulking method. In the previous caulking method, caulking force (hollow arrow in fig. 12) is applied to the sleeve 2 so as to bend the entire circumferential surface of the sleeve 2 at a time. In order to perform the primary bending, a large caulking force needs to be applied. When the number of the grooves 20 formed in the sleeve 2 is set to 50 and the total caulking force applied to the sleeve 2 is set to 750kgf, one projection is caulked at 15kgf (750 kgf/50).

Fig. 13 is a schematic view showing the caulking force applied to the sleeve 2 by the caulking method of the present invention. In the case where one projection of the sleeve 2 is caulked by one roller 16, the load on the sleeve 2 is only 15kgf × 3 — 45 kgf. Compared to the conventional caulking method in which the load on the sleeve 2 is 750kgf, the present invention can reduce the load on the sleeve 2 to 6% and prevent deterioration of deflection due to caulking. In fact, in the present invention, it has been confirmed that sufficient fixation of the sleeve 2 and the flange 4 can be achieved by a caulking force of 15kgf using simulation verification.

As described above, in the present invention, the sleeve 2 and the flange 4 are fixed by caulking. Therefore, as compared with the case of fixing by an adhesion treatment, since an adhesive is not required, the cost can be reduced. In addition, since there is no need to manage curing of the adhesive, the work space and the processing time can be reduced. On the other hand, the problem of caulking, which is poor in deflection accuracy and causes deformation (expansion) of the sleeve 2 easily, can be solved. Since the load on the sleeve 2 is small at the time of caulking, the amount of deformation of the sleeve 2 is reduced, the deflection accuracy of the sleeve 2 can be improved, and firm fixation can be achieved while suppressing deformation (expansion) of the sleeve 2.

Since the three rollers 16, and 16 are provided in two sets, both end portions of the sleeve 2 can be simultaneously caulked, and thus the time required for fixing can be shortened.

Since the outer peripheral surface (working surface) 16a of the roller 16 is inclined with respect to the axial direction of the material to be caulked 11, and the roller 16 is moved in the axial direction of the material to be caulked 11 while the roller 16 is rotated, the end portion of the liner 2 can be efficiently caulked into a curved surface shape. Thus, by further biting the sleeve 2 into the flange 4, the sleeve 2 and the flange 4 can be firmly fixed. In addition, since the roller 16 makes point contact with the end of the sleeve 2, pressure can be effectively applied to the end of the sleeve 2.

Since the rollers 16, 16 of one side and the rollers 16, 16 of the other side are moved in the axial direction while rotating in opposite directions, deformation other than the end portion of the sleeve 2 can be suppressed.

In the final process of the caulking process, since the inner arcuate surface 16c of the outer circumferential surface (machined surface) 16a of the roller 16 is in contact with the end portion of the sleeve 2, the end portion of the sleeve 2 can be further firmly bitten into the flange 4. At this time, a large force pushing the sleeve 2 in the axial direction is generated, but since a part of the biting is already made, the force to the extent of slightly bending the sleeve 2 does not cause the deformation of the sleeve 2 and does not cause the reduction of the dimensional accuracy.

Since the knurling 40 is formed at the end of the flange 4 and the end of the flange 4 is not chamfered, the sleeve 2 is caulked to a curved surface with respect to the knurling 40, and the biting of the sleeve 2 is good. Further, since the groove 20 is provided on the outer peripheral surface of the sleeve 2, the roller 16 makes point contact with the protruding portion other than the groove 20, so that the end portion of the sleeve 2 becomes easily bent.

Next, the measurement characteristics of the magnetic roller manufactured by the method for manufacturing a magnetic roller according to the present invention (hereinafter, referred to simply as an example of the present invention) will be described. In addition, for comparison with the present invention, measured characteristics of the magnetic roller (hereinafter, referred to simply as a comparative example) manufactured by the above-described conventional method in which the entire circumference of the sleeve is once bent will be described. The sleeves of the inventive and comparative examples were set to have a length of 234mm, an outer diameter of 20mm and a wall thickness of 0.3 mm.

Fig. 14 is a graph showing the measurement results of the sleeve deflection in the present invention example and the comparative example. The deflection is measured by a known method while rotating the magnetic roller around the axis. With regard to the present invention example (hatched bar graph) and the comparative example (unshaded bar graph), each 50 measurement results are shown, fig. 14A shows the measurement result of the deflection in one end portion, fig. 14B shows the measurement result of the deflection in the central portion, and fig. 14C shows the measurement result of the deflection in the other end portion. In fig. 14A to 14C, the horizontal axis represents the deflection amount (mm) and the vertical axis represents the number.

As shown in fig. 14, in the comparative example, it was observed that the deflection amount of several sleeves exceeded 0.03mm, and particularly the deflection amount in the central portion became large. In contrast, in all of the examples of the present invention, the amount of deflection in the entire region of the sleeve was suppressed to within 0.03 mm. Thus, it can be seen that: a magnetic roller required to have high deflection accuracy can be manufactured.

Fig. 15 is a graph showing the results of measuring the outer diameter of the sleeve in the present invention example and the comparative example. The sleeve outer diameter before caulking and the sleeve outer diameter after caulking in the two end portions are measured, respectively, and the amount of change is calculated. Fig. 15 shows the average values of 10 measurements of the present invention example and the comparative example.

As shown in fig. 15, in the comparative example, the outer diameter of the sleeve was changed by about 30 μm before and after the caulking process. In contrast, the present invention shows: the outer diameter of the sleeve is changed by only about 1 μm before and after the caulking process, and the sleeve is hardly deformed (expanded) even if the caulking process is performed.

Fig. 16 is a graph showing the measurement results of the fixing strength in the rotation direction of the flange in the present invention example and the comparative example. Measurements were made with a dial type torque wrench. Each of 10 measurement results is shown for the inventive example (hatched bar graph) and the comparative example (unshaded bar graph). In fig. 16, the horizontal axis represents flange fixing torque (Nm) and the vertical axis represents the number.

The average value of the flange fixing torques for the 10 magnet rollers was 5.43Nm in the comparative example, and 6.20Nm in the inventive example for this, which was about 14% higher. From this, it is understood that the torque resistance against the external torque is improved.

Furthermore, the disclosed embodiments are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is indicated not by the foregoing description but by the appended claims, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Claims (7)

1. A method for manufacturing a magnetic roller is characterized in that,

the method is used for manufacturing a magnetic roller, which has: a sleeve which is a cylindrical non-magnetic body; a magnet disposed inside the sleeve and having a plurality of magnetic poles arranged in a circumferential direction; and flanges to which both end portions of the sleeve are fixed,

when both end portions of the sleeve are fixed to the flanges, the rollers in one set are brought into contact with both end portions of the sleeve so that the outer peripheral surfaces of the rollers in one set are inclined with respect to the central axis of the magnetic roller, and the sleeve is caulked while the rollers are rotated and moved in the axial direction of the magnetic roller,

the rotational direction of the triplet of rollers in contact with one end of the sleeve is opposite to the rotational direction of the triplet of rollers in contact with the other end of the sleeve.

2. The method of manufacturing a magnetic roller according to claim 1,

the axial movement of the triplet of rollers in contact with one end of the sleeve and the triplet of rollers in contact with the other end of the sleeve in the magnetic roller direction are both movements in a direction toward the center side of the sleeve.

3. The method of manufacturing a magnetic roller according to claim 1 or 2,

the outer peripheral surface of the roller has: an inclined surface that expands from a front end surface to a rear end surface; and an inner arc surface arranged on a rear end face side of the inclined surface.

4. The method of manufacturing a magnetic roller according to claim 3,

at the end of moving the roller in the axial direction of the magnetic roller, the inner arc surface of the roller is brought into contact with the end of the sleeve.

5. The method of manufacturing a magnetic roller according to claim 1 or 2,

the center axis of the roller is inclined with respect to the center axis of the magnetic roller.

6. The method of manufacturing a magnetic roller according to claim 1 or 2,

the outer peripheral surface of the roller has: a horizontal plane that expands from a front end surface to a rear end surface; and an inner arc surface that is disposed on the rear end surface side of the horizontal plane and that inclines the center axis of the roller with respect to the center axis of the magnetic roller.

7. A manufacturing apparatus of a magnetic roller is characterized in that,

the apparatus is used for manufacturing a magnetic roller having: a sleeve which is a cylindrical non-magnetic body; a magnet disposed inside the sleeve and having a plurality of magnetic poles arranged in a circumferential direction; and flanges to which both end portions of the sleeve are fixed,

the device comprises: a caulking machine having two sets of three rollers in contact with both end portions of the sleeve; a rotating portion that rotates the caulking machine; and a moving section that moves the caulking machine in an axial direction of the magnet roller,

the rollers are arranged so that the outer peripheral surfaces thereof are inclined with respect to the central axis of the magnetic roller,

moving the roller in an axial direction of the magnet roller while the roller is rotated, and caulking the sleeve to fix the sleeve and the flange,

the rotational direction of the triplet of rollers in contact with one end of the sleeve is opposite to the rotational direction of the triplet of rollers in contact with the other end of the sleeve.

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