JPH08123200A - Magnet roll - Google Patents

Abstract

PURPOSE: To provide a magnet roll with which magnetic characteristics and strength are assured and which is producible at a low cost even if the diameter of the roll is small. CONSTITUTION: This magnet roll is formed by fixing a supporting shaft 12 to a permanent magnet member 1 formed by providing the surface integrally molded of a powder sintered magnet material to a hollow cylindrical form with plural pieces of magnetic poles. The shaft member 11 which consists of a plastically deformable material and is formed with a supporting shaft 12 at one end and a press fitting part 13 having plural pieces of projections on the outer periphery at the other end, respectively, is press fitted and engaged into and with the hollow part 1a at least at one end of the permanent magnet material 1 via the press-fitting part 13. The shaft member 11 is fixed to the permanent magnet material 1 by plastical deformation of the projection. In addition, the shaft member is so formed that the run-out on the outer peripheral surface of the permanent magnet material 1 in the non-worked state with respect to the axial line of the supporting shaft 12 of the shaft member 11 is confined to <=0.2mm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnet roll used as a developing roll or a cleaning roll in electrophotography, electrostatic recording, etc., and particularly, a magnet roll which can be manufactured with a small diameter at low cost. It is about.

[0002]

2. Description of the Related Art Conventionally, in electrophotography, electrostatic recording and the like, a magnet roll used as a developing roll or a cleaning roll is most commonly of a structure as shown in FIG. In FIG. 12, reference numeral 1 denotes a permanent magnet member, which is formed into a hollow cylindrical shape by a powder sintered permanent magnet material such as hard ferrite or a mixed material of a ferromagnetic powder material and a binder,
The support shaft 2 is coaxially fixed to the central portion.

A plurality of magnetic poles (not shown) extending in the axial direction are provided on the outer peripheral surface of the permanent magnet member 1, and these are arranged at equal or unequal intervals in the circumferential direction.
Next, a flat plate-shaped flange 3 and a shaft-equipped flange 4 are rotatably mounted on both ends 2a and 2b of the support shaft 2 via bearings 5 and 5, and the outer circumferences of the flat-plate-shaped flange 3 and the shaft-equipped flange 4 are attached. A sleeve 6 formed in a hollow cylindrical shape is fitted in the.

The plate-like flange 3, the shaft-equipped flange 4 and the sleeve 6 are made of a non-magnetic material such as aluminum alloy or stainless steel. 7
Is a seal member, and is fitted between the flat plate-shaped flange 3 and the end portion 2a of the support shaft 2. Further, the permanent magnet member 1 often has a diameter of 10 to 60 mm and a length of 200 to 350 mm.

With the above configuration, the relative rotation between the permanent magnet member 1 and the sleeve 6 (for example, the permanent magnet member 1 is fixed and the sleeve 6 is rotated by the flange 4 with the shaft) causes the outer peripheral surface of the sleeve 6 to be rotated. The magnetic developer is adsorbed to form a magnetic brush and a predetermined developing operation or the like is performed, or an excess magnetic developer after transfer from the surface of the photoconductor is adsorbed and a predetermined cleaning operation is performed.

The flat flange 3 shown in FIG.
As shown in FIG. 13, a hollow cylindrical protrusion 3a is provided at the center, the seal member 7 (see FIG. 12) is omitted, and the sleeve 6 is driven or the sleeve 6 is driven through the protrusion 3a. It may be used for support.

[0007]

When forming the permanent magnet member 1 having the above-mentioned structure, first, in the case of using a powder sintered magnet material such as hard ferrite, for example, an appropriate amount of polyvinyl alcohol (P) is added to barium ferrite particles.
VA) is added and kneaded with a double-arm kneader, and then granulated and dried raw material powder is prepared. Next, this raw material powder is filled into a bag of a thin film made of rubber or plastic, which has a core rod in the center, and is placed in a liquid such as oil, glycerin, or water, and liquid pressure is applied. Pressure molding (hydrostatic pressure molding or rubber pressing) is performed from the surroundings and firing is performed to mold a hollow cylindrical material.

A separately prepared support shaft (see reference numeral 2 in FIG. 12) is fixed to the hollow hole of the above material with an adhesive and then subjected to predetermined processing to form a plurality of magnetic poles extending in the axial direction on the outer peripheral surface. It is provided.

However, when the above means is used, in addition to the relatively complicated work of molding the raw material from the raw material powder, the work of fixing the support shaft to the hollow hole of the raw material is also complicated, and the manufacturing and assembling are performed. There is a problem that the man-hour becomes large and the manufacturing cost rises. In particular, since the hollow hole of the material and the support shaft are in a loose state, it is necessary to completely fill the gap between the two with the adhesive. Therefore, when the material and the support shaft are combined, excess adhesive is removed. Need to be removed and cleaned. Further, there is a drawback that heating is required to cure the adhesive.

On the other hand, a means for molding the permanent magnet member 1 by a so-called bonded magnet containing a mixture of ferrite particles and a thermoplastic resin material as a main component is also commonly used. In this case, an injection molding die is used, the support shaft 2 is previously inserted in a predetermined portion of the molding space, and the thermoplastic resin material is heated and melted to be injected and filled into the molding space,
It may be taken out after cooling and solidification. In addition, in order to improve the magnetic characteristics, a magnetic field forming means for providing anisotropy by providing a magnetic field generating means in the injection molding die is commonly used.

The permanent magnet member manufactured by the anisotropic bonded magnet as described above has advantages of relatively small manufacturing steps and light weight, but on the other hand, the injection molding die becomes complicated. At the same time, when the number of magnetic poles is large, there may occur a situation where molding in a magnetic field is impossible. In particular, if the permanent magnet member has a small diameter of, for example, 20 mm or less, the magnetic field generating means may come close to or come into contact with each other, and it may be substantially impossible to manufacture an injection molding die. Therefore, there is a problem that the degree of freedom of the magnetization pattern is small.

As an example of a magnet roll made of the above-mentioned bonded magnet, there has been proposed one in which the supporting shaft 2 at the central portion is omitted and the diameter is equal over the entire length (for example, Japanese Patent Laid-Open No. 62-62). 8109, Actual Kaihei 5-504
69 publication). With this configuration,
It is said that the support shaft 2 is not required, magnetic design can be easily performed, and sufficient magnetic force can be obtained even with a small diameter.

However, in the magnet roll having the above-mentioned structure, since the permanent magnet members are formed to have the same diameter over the entire length, the size of the bearing portion is inevitably large, and the size of the entire apparatus is increased. . Therefore, it is conceivable to reduce the diameter of the bearing portion by molding or processing to reduce the size of the entire device. In this case, the processing for reducing the diameter of the bearing portion is easy, but the wear resistance and strength of the bearing portion are insufficient, resulting in a problem of poor durability.

It has also been proposed to provide cap-shaped support fittings with shafts on both ends of the above-mentioned cylindrical magnets of equal diameter (see, for example, Japanese Utility Model Laid-Open No. 55508/1993).
According to this proposal, the diameter of the bearing portion can be reduced, and the wear resistance can be improved. However, there are still problems with the concentricity and strength of the support metal fittings, there is also a question of cost reduction, and there is a need for further improvement in terms of practicality.

In order to solve the problem of strength of the above-mentioned bonded magnet, the present applicant forms an integral cylindrical body over the entire length with a ferrite-based sintered magnet material, and forms an intermediate body at both ends of this cylindrical body. Has been proposed to form a shaft portion having a diameter smaller than that of the shaft portion (Japanese Patent Application No. 5-137153).
issue).

According to the above proposal, it is possible to expect an effect that a magnet roll having high magnetic characteristics and a large degree of freedom of a magnetizing pattern can be relatively easily manufactured, but there are still some problems.

That is, since the cylindrical body made of the ferrite-based sintered magnet material is hard, it is necessary to depend on the grinding work to form the shaft portions at both ends, and the grinding allowance for forming the shaft portion is required. Since it is large, there is a problem that the grinding work takes time. Further, since the ferrite-based sintered magnet material is brittle, the strength of the shaft portion formed by grinding is insufficient, and undesired breakage, chipping, etc. may occur during handling in the magnetizing step and other working steps after grinding. There is a problem that accidents are likely to occur.

The present invention solves the problems existing in the above-mentioned prior art and improved invention, and provides a magnet roll which can be manufactured at a low cost while ensuring the magnetic characteristics and strength even with a small diameter. With the goal.

[0019]

In order to achieve the above object, in the first aspect of the invention, first, a permanent magnet is formed by integrally molding a powder sintered magnet material into a hollow cylindrical shape and providing a plurality of magnetic poles on the surface. In a magnet roll formed by fixing a support shaft to a member, a shaft made of a plastically deformable material, in which a support shaft is formed at one end and a press-fitting portion having a plurality of protrusions is formed at the outer circumference of the other end. The member is press-fitted into the hollow portion of at least one end of the permanent magnet member via the press-fitting portion, and the shaft member is fixed to the permanent magnet member by the plastic deformation of the protrusion, and the shaft of the support shaft of the shaft member is fixed. We adopted the technical means of configuring the outer peripheral surface of the unprocessed permanent magnet member with respect to the axis so that the runout of the outer surface is 0.2 mm or less.

Next, in the second aspect of the present invention, there is provided a magnet roll formed by integrally molding a powder-sintered magnet material into a hollow cylinder, and fixing a support shaft to a permanent magnet member having a plurality of magnetic poles provided on the surface thereof. , A shaft member made of a plastically deformable material and having a support shaft at one end and press-fit portions each having a plurality of protrusions on the outer circumference of the other end are formed on at least one end of the permanent magnet member. The shaft member is press-fitted into the hollow portion via the press-fitting portion, the shaft member is fixed to the permanent magnet member by plastic deformation of the projection, and the shaft member has an outer peripheral surface of the support shaft that is not machined. We adopted the technical means of constructing by machined with reference to.

Further, in a third aspect of the present invention, there is provided a magnet roll formed by integrally molding a powder sintered magnet material into a hollow cylindrical shape and fixing a support shaft to a permanent magnet member having a plurality of magnetic poles provided on the surface thereof. A support shaft made of a metal material is provided so as to penetrate coaxially with the permanent magnet member, and a base having a hole for inserting the support shaft and a slit radially formed around the hole and a periphery of the base. The washer having the formed outer peripheral portion is formed such that at least a part of the inner peripheral edge of the base portion is locked to the outer peripheral surface of the support shaft, and the outer peripheral portion is pressed against the end surface of the permanent magnet member. A technical means was adopted in which the outer peripheral surface of the non-machined permanent magnet member fitted to the support shaft and unmachined with respect to the axis of the support shaft had a deflection of 0.2 mm or less.

According to a fourth aspect of the present invention, in a magnet roll formed by integrally molding a powder sintered magnet material into a hollow cylindrical shape and fixing a support shaft to a permanent magnet member having a plurality of magnetic poles on the surface, A support shaft made of a metal material is provided so as to penetrate coaxially with the permanent magnet member, and a base having a hole for inserting the support shaft and a slit radially formed around the hole and a periphery of the base. The washer having the formed outer peripheral portion is formed such that at least a part of the inner peripheral edge of the base portion is locked to the outer peripheral surface of the support shaft, and the outer peripheral portion is pressed against the end surface of the permanent magnet member. A technical means is adopted in which the support shaft is fitted to the support shaft, and the support shaft is formed by machining the outer peripheral surfaces of both end portions of the permanent magnet member in a non-machined state as a reference. .

[0023]

With the above construction, the permanent magnet member can be easily molded, and the fixing strength of the shaft member or the support shaft can be greatly improved. Further, the concentricity between the support shaft or the support shaft of the shaft member and the permanent magnet member is ensured, and the fixing work becomes easy, and the manufacturing cost can be reduced.

[0024]

1 is a longitudinal sectional view of an essential part showing an example of means for extrusion-molding a permanent magnet member in an embodiment of the present invention. In FIG. 1, reference numeral 31 is an extrusion cylinder, in which an appropriate heating means (not shown) is interposed and a screw 32 is coaxially incorporated. Next, 33 is a die, 34 is a core metal, and an extrusion die 35 having a molding space 36 having a ring-shaped cross section is formed, and is integrally fixed to the discharge port of the extrusion cylinder 31. Next, for example, a raw material containing Ba ferrite as a main component is extruded from the extrusion die 35 to obtain a hollow cylindrical and long raw material 37.

The material 37 is cut into a predetermined axial length, dried as described later, and then sintered at a predetermined temperature.
Since the outer diameter of both ends of the material 37 is slightly bulged by this sintering treatment, the bulging portions of both ends of the material 37 are cut and removed after sintering.
A permanent magnet member 1 (see FIG. 12) having a predetermined axial length is obtained.

Next, the raw materials constituting the permanent magnet member 1 will be described.
Describe. First of all, a magneto-plastic with a particle size of 0.7-1.5 μm
Ferrite particles (MO ・ n
Fe ₂O₃: M = one or more of Ba, Sr, and Pb, n =
5-6) and a mixed solution such as water and alcohol.
Mix with the ingredients to prepare a mud-like or ointment-like raw material.
In this case, the ferrite particle size is too small
And the moldability during extrusion molding decreases, while the particle size is too large.
If this is the case, the density of the sintered body will decrease and the magnetic properties will decrease,
Not good. Therefore, the particle size is in the range of 0.7-1.5 μm
It is better to use

If the amount of the mixed liquid added to the ferrite particles is too small, the viscosity of the raw material becomes large, the moldability at the time of extrusion molding is deteriorated, and the density of the molded body locally varies, and at the time of sintering. In this case, cracks will be generated, which is not preferable. On the other hand, if the amount of the mixed solution added is too large, cracks occur when the molded body is dried, and high density during molding cannot be obtained, which is inconvenient. Therefore, the addition amount of the mixed solution is 1 with respect to the ferrite particles.
It is preferable to set it in the range of 0 to 15% by weight.

[0028] The ferrite particles are methyl cellulose,
Moldability can be improved by adding an organic binder such as carboxymethyl cellulose. However, if the amount of the organic binder added is too large, cracks occur during extrusion molding, and these cracks develop during sintering, which is not preferable. Therefore, the amount of the above organic binder added to the ferrite particles is 2% by weight.
Below, it is preferably 0.5 to 1.0% by weight.

Further, the ferrite particles contain 0.1 to 3% by weight of B.
By adding an oxide such as ₂ O ₃ , CaO or SiO ₂ , the density of the sintered body can be improved and the magnetic characteristics can be improved.

The material 37, which is a molded body obtained by the above-mentioned extrusion molding means, needs to be dried because it is in a wet state immediately after molding, but since the progress state of drying is different between the surface and the inside. , Bending, cracks, etc. occur.
For this reason, for example, a means for wrapping the material 37 with air-permeable wrapping paper and performing natural drying is adopted.
However, with this natural drying method, 1 to
It takes a long time of 2 weeks, and there is a problem that productivity is significantly reduced.

Further, since only the both ends of the raw material 37 are supported, there is a problem that the raw material 37 is bent during drying and the straightness is lowered. In order to prevent the occurrence of such bending, it is necessary to frequently change the support position of the material 37, but there is no choice but to rely on manual work.
Not only does it lower productivity, but it also raises the manufacturing cost.

In the embodiment of the present invention, the above-mentioned problems are solved and bending and warping are not generated,
In order to uniformly and efficiently dry and to prevent the occurrence of shake, the following drying means was adopted.

FIG. 2 is a perspective view of an essential part showing a drying device according to an embodiment of the present invention. In FIG. 2, reference numeral 21 denotes a roller, which are arranged with their axes parallel to each other and formed so as to rotate in the same direction and at the same number of rotations. Reference numeral 22 is a long cylindrical extruded body, for example, an outer diameter dimension D, axial length dimensions L, L ≧ by an extrusion molding means as shown in FIG.
It is molded in 3D. The distance d between the rollers 21, 21 is d <D. Therefore, the long cylindrical extruded body 22 is held on the two rollers 21 and 21, and is rotated by the rotation of the rollers 21 and 21 in the arrow direction.

With the above structure, the long cylindrical extruded body 22 has two rollers 21, 21 over the entire axial length.
It is supported above and rolls slowly. In this state, by supplying hot air to the long cylindrical extruded body 22, or by irradiating microwaves or far infrared rays,
The long cylindrical extruded body 22 can be uniformly dried without being deformed, bent, warped or the like. Further, since the long cylindrical extruded body 22 is evenly supported on the two rollers 21 and 21 over the entire axial length, the long cylindrical extruded body 22 which is soft and wet. It is possible to prevent undesired local crushing and cracking due to its own weight and maintain straightness.

In the above case, if the number of revolutions of the long cylindrical extruded body 22 is small, undesired local deformation occurs due to the own weight of the flexible extruded body, which is not preferable.
Further, when the number of revolutions of the long cylindrical extruded body 22 is high,
This is inconvenient because it promotes deformation due to rotation or rolling. Therefore, it is preferable to set it to 2 to 50 rpm.

FIG. 3 is a front view of a main part of another drying device according to the embodiment of the present invention, and the same parts are designated by the same reference numerals as those in FIG. In FIG. 3, reference numeral 23 denotes a frame, which supports the roller 21 with respect to a horizontal plane so that their axes form an inclination angle of θ. 24 is a support member, which supports one end surface of the long cylindrical extruded body 22,
And it is formed to be rotatable.

With the above structure, the long cylindrical extruded body 22 can be rotatably supported on the two rollers 21. Therefore, the long cylindrical extruded body is formed in the same manner as in the above embodiment. 22 can be evenly dried without deformation. Since one end surface of the long cylindrical extruded body 22 is supported by the support member 24, the long cylindrical extruded body 22 is prevented from moving in the axial direction on the roller 21 and rolls at a fixed position. Can be rotated.

In the above case, if the axis of the roller is inclined with respect to the horizontal plane, it is possible to prevent the long cylindrical extruded body 22 that rotates or rolls on the roller 21 from moving in the axial direction. If it is too large, the long cylindrical extruded body 22 is deformed in the axial direction due to its own weight, which is not preferable. Therefore, the inclination angle is preferably 5 to 10 °.

FIG. 4 is an explanatory view of a vertical cross-sectional structure of a main part showing an embodiment of the present invention. In FIG. 4, the permanent magnet member 1 is made of a ferrite magnet (YBM-3 made by Hitachi Metals), for example, outer diameter dm = 16 mm, inner diameter di = 10 mm, length Lm = 233.
It is formed in a hollow cylindrical shape of mm. To form such a hollow-cylindrical permanent magnet member 1, the extrusion molding means and the drying means as described above are used.

That is, first, BaO having a particle size of 0.7 to 1.5 μm is used.
Mixing 1 wt% PVA (polyvinyl alcohol) and 10 wt% water with 6Fe ₂ O ₃ ferrite particles,
A raw material in the form of a slurry is prepared, extrusion-molded by the extrusion-molding means shown in FIG. 1, cut into a predetermined length, and dried by the drying means shown in FIG. 2 or 3. The obtained long cylindrical extrusion-molded body 22 is sintered at 1100 to 1300 ° C., and the outer diameter bulging portions at both ends are cut to form the permanent magnet member 1 shown in FIG. In this case, the outer diameter of the permanent magnet member 1 varies by 0.2 mm due to the management of each manufacturing condition.
It can be kept below.

Next, in FIG. 4, reference numeral 11 denotes a shaft member, which is a plastically deformable material such as A3003, A5052, A.
A support shaft 12 is formed at one end, a press-fitting portion 13 is formed at the other end, and a stopper portion 14 is formed at an intermediate portion, using an aluminum alloy such as 5056. The press-fitting part 13 is
As will be described later, a plurality of protrusions are formed on the outer circumference, and the axial length Ls thereof is set to 15 mm, for example. On the other hand, the outer diameter ds of the support shaft 12 is determined in correspondence with the specifications of the device to be incorporated, but is formed to be 6 mm, for example.

FIG. 5 is an enlarged explanatory view of an end face of the main portion showing the press-fitting portion 13 in FIG. 4, and a plurality of protrusions 15 each having a triangular cross-sectional shape are formed on the outer periphery so as to extend in the axial direction. It should be noted that d ₁ , d ₂ and d _p are the diameter of the valleys, the diameter of the peaks and the pitch diameter of the triangular protrusions 15, respectively.
In this case, d _p is formed to be ((d ₁ + d ₂ ) / 2), and is preferably formed to be substantially equal to the inner diameter di of the hollow portion 1a at the end of the permanent magnet member 1 shown in FIG.

With the above structure, when the shaft member 11 is press-fitted into the hollow portion 1a through the press-fitting portion 13 as shown in FIG. 4, the shaft member 11 is firmly fixed to the end portion of the permanent magnet member 1. You can In this case, since the projection 15 shown in FIG. 5 is plastically deformed by the hollow portion 1a shown in FIG.
In addition to facilitating the press-fitting work of (1) and firmly adhering to the hollow portion 1a, the fixing strength can be improved. An adhesive may be used in combination with the press-fitting portion 13 and the hollow portion 1a.

Next, FIG. 6 is a vertical cross-sectional view showing an example of a press-fitting jig in the embodiment of the present invention, which is formed of, for example, stainless steel into a hollow cylindrical shape. The support portion 1 is provided in the press-fitting jig 16.
7, 18 and 19 are provided respectively, but these support portions 17 to
The shape and size of 19 are formed so as to correspond to the shape and size of the support shaft 12, the stopper portion 14 and the permanent magnet member 1 shown in FIG.

FIG. 7 is an explanatory view showing a mode of press fitting by the press fitting jig 16 of FIG. In FIG. 7, first, the press-fitting jig 1
6, the shaft member 11 is inserted, and the support shaft 12 and the stopper portion 14 of the shaft member 11 are respectively attached to the support portion 1 in the press-fitting jig 16.
Position in 7,18. Next, if the permanent magnet member 1 is press-fitted in the arrow direction along the support portion 19 of the press-fitting jig 16,
The press-fitting portion 13 of the shaft member 11 is the hollow portion 1a of the permanent magnet member 1.
The shaft member 11 is press-fitted into the shaft member 11 and can be firmly fixed to the permanent magnet member 1 in the above-described manner.

With respect to the 50 magnet rolls manufactured as described above, the outer diameter dm and the deflection of the outer peripheral surface with respect to the axis of the support shaft 12 were measured. As a result, the outer diameter dm =
16 mm (σ = 0.02 mm), deflection δ = 0.1 mm (σ = 0.05 mm)
I got As a result of asymmetric 4-pole magnetization of the permanent magnet member 1 constituting the magnet roll, the surface magnetic flux density on the sleeve made of non-magnetic material and having an outer diameter of 18 mm is 500 G, and the axial variation is ±. It was 50G. When the press-fitting portion 13 is d ₁ = 3.9 mm and d ₂ = 4.1 mm, the circumferential bonding strength between the permanent magnet member 1 (the inner diameter is 4.0 mm on average) and the shaft member 11 is 50 kgf.
It was cm, and it was confirmed that it had a bonding strength almost equal to that of the conventional one.

The permanent magnet member 1 constituting the magnet roll of the present invention has a water content of 10 to 10 in the raw material as described above.
When the long cylindrical extruded body 22 is dried at 15% by weight, it is supported on the roller 21 in a rolling state, so that the runout is 0.2 mm or less, preferably 0.1 mm with the outer peripheral surface being unprocessed. Because of the following, it is not necessary to machine (for example, grind) the outer peripheral surface of the permanent magnet member 1 as in the conventional one.

Therefore, although the machining cost can be greatly reduced, the shaft member 11 is supported on the basis of the outer peripheral surface of the permanent magnet member 1 for the specifications requiring higher accuracy. The outer peripheral surface of the shaft 12 can be machined (for example, ground). However, since the machining cost in this case is extremely small, the increase in machining cost can be suppressed to a small extent.

FIG. 8 is a longitudinal sectional view of a main part showing another embodiment of the present invention, and the same parts are designated by the same reference numerals as those in FIGS. 4 and 12. In FIG. 8, the support shaft 2 is, for example, steel (SUM material) or austenitic stainless steel (SUS).
303, 304 material) and the like, penetrates the hollow portion 1a of the permanent magnet member 1 and is fixed to the permanent magnet member 1 by a washer 8 formed as described later.

9A and 9B are explanatory views showing the washer 8 in FIG. 8, in which FIG. 9A shows an end face and FIG. 9B shows a side face. In FIG. 9, the washer 8 is formed in a cone shape from a material having rigidity and elasticity such as spring steel or stainless steel for spring, and has a hole 81 through which the support shaft 2 shown in FIG. 8 is inserted.
And a radial slit 8 provided around the hole 81.
It has a base portion 83 having 2 and an outer peripheral portion 84 provided around the base portion 83. An edge portion 85 is formed on the inner peripheral surface of the base portion 83 at the open end portion of the slit 82. The inner diameter of the hole 81 is preferably slightly smaller (for example, 0.1 mm in diameter) than the outer diameter of the support shaft 2 shown in FIG.

FIG. 10 is a vertical sectional view showing an example of an assembling apparatus according to another embodiment of the present invention. In FIG. 10, the assembling apparatus 9 has a pair of jigs 51 and 52 that are coaxially provided and that are movable in the axial direction. These jigs 51, 52 are provided with support portions 53, 54 and 55, 56 for accommodating and holding the permanent magnet member 1 and the support shaft 2, respectively. As shown in FIG. 10, the support shaft 2 is inserted into the hollow portion 1 a of the permanent magnet member 1, and the washer 8 is installed at both ends of the support shaft 2 to be installed in the assembling device 9.

Next, the jig 5 is driven by a driving means (not shown).
1, 52 respectively move in the arrow X _1, X ₂ direction, the bottom surface 53a of the support portions 53 and 54, if pressed washer 8 by 54a, is formed on the inner peripheral edge of the base portion 83 of the washer 8 shown in FIG. 9 The edge portion 85 cuts into the outer peripheral surface of the support shaft 2 shown in FIG. The washer 8 is attached to the end face of the permanent magnet member 1 at the outer peripheral portion 8
It is elastically and firmly pressed against the sheet via 4. Therefore support shaft 2
Thus, the permanent magnet member 1 can be firmly fixed.

FIG. 11 is a vertical sectional view of a modification of the support shaft 2 shown in FIG. 10, and the same parts are designated by the same reference numerals as those in FIGS. 10 and 12. In FIG. 11, the outer diameters of the end portions 2a and 2b of the support shaft 2 are set to 0.5 mm from the middle portion.
Form a small diameter of less than mm. By forming in this way, even when the washer 8 is mounted on the support shaft 2, the outer peripheral surfaces of the end portions 2a and 2b are not scratched by sliding friction.

The magnet roll assembled as described above has a runout of 0.2 mm or less, preferably 0.1 mm or less, even when the outer peripheral surface of the permanent magnet member 1 is in a non-processed state as in the above embodiment. However, in the case of higher precision specifications, the outer peripheral surface of the permanent magnet member 1 is used as a reference,
The outer peripheral surfaces of both ends of the support shaft 2 can be machined (for example, ground). However, the machining cost in this case is extremely small as in the case of the above-mentioned embodiment, and therefore the increase in machining cost is slight.

Next, the joint strength between the permanent magnet member 1 and the support shaft 2 in the magnet roll shown in FIG. 8 will be described. In this case, the outer diameter of the permanent magnet member 1 was 16 mm, the inner diameter was 6 mm, and the support shaft 2 was formed of SUS304 to have an equal outer diameter of 5 mm. The washer 8 is made of spring steel and has a hardness of HRC.
Formed at 45 °, D = 15.5mm, d = 4.9m in FIG.
m, H = 2 mm, t = 0.3 mm. It was confirmed that the bonding strength between the support shaft 2 and the permanent magnet member 1 in the circumferential direction was 30 kgf · cm, and that it could be sufficiently used practically.

In the above embodiment, the permanent magnet member 1
Although the description has been given of the example in which the magnet is formed of a ferrite-based sintered magnet material, it may be formed of a rare earth-based sintered magnet material. As the material forming the shaft member 11, a non-magnetic material or a magnetic material can be used as long as it is plastically deformable and has a predetermined mechanical strength, and a non-metallic material such as engineering plastic is also used. Can be used.

Furthermore, the cross-sectional shape of the press-fitting portion 13 formed on the shaft member 11 may be other than triangular, and the projection 15
Not only in the axial direction but also in the shape of a screw, it may have an independent shape in the axial direction and / or the circumferential direction, respectively. It is also possible to provide the press-fitting portion 13 with, for example, a slit extending in the axial direction so as to give some elasticity in the direction orthogonal to the axial line. Further, the shaft member 11 may be provided at one end of the permanent magnet member 1 and the outer periphery or hollow portion of the permanent magnet member 1 may be used as a sliding surface directly as a supporting means for the other end.

It is needless to say that the outer peripheral portion 84 of the washer 8 for fixing the permanent magnet member 1 and the support shaft 2 is not limited to a circular shape, but may be a polygonal shape or another shape.

[0059]

EFFECTS OF THE INVENTION Since the present invention has the structure and operation as described above, the following effects can be obtained.

(1) Since the permanent magnet member can be manufactured with high accuracy of coaxiality, machining of the outer peripheral surface of the permanent magnet member after fixing the shaft member or the support shaft is unnecessary, and the permanent magnet member is not processed. It can be used in the state, and the manufacturing cost can be reduced significantly. (2) In the case of requiring high accuracy, it is necessary to machine the outer peripheral surface of the support shaft with reference to the outer peripheral surface of the unprocessed permanent magnet member, but the machining allowance is extremely small,
The increase in machining costs can be negligible. (3) The permanent magnet member and the shaft member or the support shaft are firmly fixed to each other via the press-fitting portion or the washer, so that sufficient bonding strength in the circumferential direction can be secured.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an essential part showing an example of means for extrusion-molding a permanent magnet member in an example of the present invention.

FIG. 2 is a perspective view of a main part of a drying device according to an embodiment of the present invention.

FIG. 3 is a main part front view showing another drying device according to the embodiment of the present invention.

FIG. 4 is a vertical cross-sectional configuration explanatory view of a main part showing an embodiment of the present invention.

5 is an enlarged explanatory view of an end face of a main part showing a press-fitting part 13 in FIG.

FIG. 6 is a vertical sectional view showing an example of a press-fitting jig in the embodiment of the present invention.

FIG. 7 is an explanatory view showing a mode of press-fitting by the press-fitting jig of FIG.

FIG. 8 is a longitudinal sectional view of a main part showing another embodiment of the present invention.

9 is an explanatory view showing a washer 8 in FIG.
(A) shows an end face and (b) shows a side face.

FIG. 10 is a vertical sectional view showing an example of an assembling apparatus according to another embodiment of the present invention.

11 is a vertical cross-sectional view of a modified example of the support shaft 2 shown in FIG.

FIG. 12 is a partially omitted vertical sectional view showing an example of a conventional magnet roll.

FIG. 13 is a longitudinal sectional view of a main part showing another example of a conventional magnet roll.

[Explanation of symbols]

 1 Permanent magnet member 2 Support shaft 8 Washer 11 Shaft member

Claims (4)

[Claims] 1. A magnet roll formed by integrally molding a powder-sintered magnet material into a hollow cylinder, and fixing a support shaft to a permanent magnet member having a plurality of magnetic poles provided on the surface thereof. A shaft member having a support shaft at one end and a press-fitting portion having a plurality of protrusions on the outer circumference of the other end, respectively, is inserted into the hollow portion of at least one end of the permanent magnet member via the press-fitting portion. The shaft member is fixed to the permanent magnet member by the plastic deformation of the projection, and the runout of the outer peripheral surface of the unprocessed permanent magnet member with respect to the axis of the shaft of the shaft member is 0.2 mm or less. A magnet roll characterized by being configured as described above. 2. A magnet roll formed by integrally molding a powder-sintered magnet material into a hollow cylinder and having a plurality of magnetic poles on the surface and a support shaft fixed to the permanent magnet member. A shaft member having a support shaft at one end and a press-fitting portion having a plurality of protrusions on the outer circumference of the other end, respectively, is inserted into the hollow portion of at least one end of the permanent magnet member via the press-fitting portion. The shaft member is fixed to the permanent magnet member by plastic deformation of the projection, and the shaft member is machined with the outer peripheral surface of the support shaft being the unmachined state as a reference. A magnet roll characterized by being formed. 3. A magnet roll formed by fixing a support shaft to a permanent magnet member integrally formed in the shape of a hollow cylinder from a powder sintered magnet material and having a plurality of magnetic poles on the surface thereof. Is provided so as to penetrate coaxially with the permanent magnet member, and has a hole through which the support shaft is inserted, and a base having a slit radially formed around the hole, and an outer peripheral portion formed around the base. At least a part of the inner peripheral edge of the base portion is locked to the outer peripheral surface of the support shaft, and the washer is fitted to the support shaft such that the outer peripheral portion is pressed against the end surface of the permanent magnet member. A magnet roll characterized in that the outer peripheral surface of the non-machined permanent magnet member with respect to the axis of the support shaft has a runout of 0.2 mm or less. 4. A magnet roll formed by integrally molding a powder sintered magnet material into a hollow cylindrical shape and fixing a support shaft to a permanent magnet member having a plurality of magnetic poles provided on the surface thereof. Is provided so as to penetrate coaxially with the permanent magnet member, and has a hole through which the support shaft is inserted, and a base having a slit radially formed around the hole, and an outer peripheral portion formed around the base. At least a part of the inner peripheral edge of the base portion is locked to the outer peripheral surface of the support shaft, and the washer is fitted to the support shaft such that the outer peripheral portion is pressed against the end surface of the permanent magnet member. A magnet roll characterized in that the support shaft is formed by machining the outer peripheral surface of both ends of the support shaft with the outer peripheral surface of a non-processed permanent magnet member as a reference.