JP2005349409A - Rolling method and rolling metal mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling method, by which irregularities for accurately and surely carrying a member represented by recording media are formed on the surface of a shaft even if the shaft has a shape to be easily deformed, and to provide a rolling metal mold for the method. <P>SOLUTION: A rolling metal mold 10 has 1st grooves 11 formed into V-shape, and further has 2nd grooves 12, which are formed between the 1st grooves 11, which are shallow than the 1st grooves 11, and whose cross-sectional area is larger than that of the 1st groove 11. A rolling metal mold 20 has grooves 21 formed into V-shape. Using the rolling metal mold 10 and the rolling metal mold 20, irregularities 110 are formed on the surface of a shaft 100. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rolling method for forming irregularities on the surface of a shaft by pressing and rotating a shaft to be rolled by a plurality of rolling dies, and the rolling die.

  2. Description of the Related Art Conventionally, copying machines, printers, and the like have been provided with a recording medium transport mechanism that moves recording media one by one and transports them to a necessary part. Such a recording medium transport mechanism includes a transport roller that transports the recording medium by rotating in contact with the surface of the recording medium. Here, in order to accurately and reliably convey the recording medium, a conveyance roller in which a plurality of spike-like protrusions are formed on a metal round bar has been proposed (see Patent Document 1). In addition, a conveyance roller in which the shaft is roughened by electric discharge machining and further metal-plated is proposed (see Patent Document 2). However, in the technique proposed in Patent Document 1, in forming a plurality of spike-shaped protrusions on a metal round bar, a step of arranging the metal round bar on the V block, a metal round bar by rotating a stepping motor The step of determining the machining position, the step of inserting the holding bush into the metal round bar, the step of lowering the punch unit and cutting the peripheral surface of the metal round bar are required. Therefore, there is a problem that the number of processes is large. In addition, the technique proposed in Patent Document 2 is a method in which a shaft is placed in a water tank for electric discharge machining, a current of several tens of amperes is applied to roughen the surface, and further, electroplating is performed. There is a problem that management is complicated.

Here, there is known a rolling method for forming irregularities on the surface of the shaft by rotating the shaft to be processed with a plurality of rolling dies. For example, the surface of a shaft is plastically deformed by two rolling molds having tooth-shaped portions having different lengths alternately on the protruding surface, and the heights of the protrusions formed on the shaft surface are alternately A method of processing so as to have a height difference has been proposed (see Patent Document 3). Further, the shaft surface is plastically deformed by a first rolling mold in which triangular grooves are formed and a second rolling mold in which triangular grooves and trapezoidal grooves are formed, and needles are formed on the shaft surface. A method for forming a protrusion having a claw and a protrusion having a flat top has been proposed (see Patent Document 4). According to these methods, a plurality of irregularities can be easily formed on the surface of the transport roller.
Japanese Patent No. 3271848 JP 2001-63861 A JP 2002-68514 A JP 2004-1925 A

  However, the methods proposed in Patent Document 3 and Patent Document 4 described above cause the shaft surface to be plastically deformed into a shape that conforms to a rolling die, and thus a large force acts on the shaft itself. Therefore, there is a problem that the shaft is deformed when an attempt is made to form irregularities on the surface of a hollow cylindrical shaft or a shaft having a protruding portion. In order to solve this problem, if the plastic deformation of the shaft surface is suppressed to a small level, there arises a problem that it is difficult to form irregularities for accurately and reliably conveying the recording medium.

  In view of the above circumstances, the present invention is capable of forming irregularities for accurately and reliably conveying a member typified by a recording medium on the surface of a shaft having a shape that is easily deformed. It aims at providing a processing method and its rolling die.

The rolling processing method of the present invention that achieves the above object is a rolling processing method for forming irregularities on the surface of the shaft by rotating the shaft to be rolled by pressing it with a plurality of rolling dies.
A plurality of first grooves having a predetermined depth are provided, and the first grooves are shallower than the first grooves, and the area of the grooves on the cross section is between the first grooves and the first grooves. A plurality of rolling molds including at least one rolling mold having the same or a second groove wider than the first groove are rotated while pressing the shaft.

  In the conventional rolling processing methods proposed in Patent Document 3 and Patent Document 4, the metal of the shaft to be processed flows into the shallow groove of the tooth-shaped grooves of the rolling mold, and After the shallow groove is filled, the shaft metal must move to the deep grooves that are separated from each other by plastic deformation. Do not fill with shaft metal. Therefore, in the case of the rolling processing methods proposed in Patent Document 3 and Patent Document 4, it is necessary to apply a very large force to the shaft, which is not suitable when the object to be processed has a shape that is easily deformed, such as a hollow cylinder. .

  On the other hand, according to the rolling processing method of the present invention, the deeper groove that needs to be finally filled is buried first or simultaneously with the shallower groove, and the shaft to be machined is processed. Rolling can be performed only by applying a relatively weak force to the surface. Therefore, even if the shaft has a shape that easily deforms, irregularities for accurately and reliably conveying a member typified by a recording medium can be formed on the surface of the shaft.

  Here, it is preferable that the first groove is a V-shaped groove and the second groove is a groove having a flat bottom.

  In this case, when the member is pierced by the protrusion formed by the first groove, the member is received by the flat top formed by the bottom of the second groove, and thus the protrusion formed by the first groove is used. The said member can be pierced reliably. Therefore, the member can be conveyed more accurately and reliably.

Further, the rolling mold of the present invention that achieves the above object is at least one of a plurality of rolling molds that form irregularities on the surface of the shaft by pressing and rotating the shaft to be rolled. A rolling mold,
A plurality of first grooves of a predetermined depth;
A second groove formed between the first grooves, which is shallower than the first grooves and has the same area as the first grooves or wider than the first grooves. The groove is formed.

  In the rolling mold of the present invention, the deeper groove that needs to be finally filled is buried first or simultaneously with the shallower groove, so that a relatively weak force is applied to the shaft to be processed. Rolling work is possible only by making it act. Therefore, even if the shaft has a shape that easily deforms, irregularities for accurately and reliably conveying a member typified by a recording medium can be formed on the surface of the shaft.

  According to the rolling processing method and the rolling die of the present invention, the shaft surface is provided with irregularities for accurately and reliably conveying a member typified by a recording medium even on a shaft having a shape that is easily deformed. Can be formed.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 is a view showing a state where irregularities are formed on the shaft surface in the rolling die according to the first embodiment of the present invention, and FIG. 2 is a view showing a part of a cross section of the rolling die shown in FIG. It is.

  In FIG. 1, cylindrical rolling dies (roll dies) 10 and 20 that rotate (rotate counterclockwise) in the direction of arrow A, and the direction of arrow A provided between the rolling dies 10 and 20 are shown. A shaft 100 that rotates (rotates clockwise) in the direction of arrow B in the reverse direction is shown. The shaft 100 is a shaft to be rolled, and the details of the shaft 100 will be described later. As the shaft 100 is pressed between the rolling dies 10 and 20 and rotated, irregularities 110 are formed on the surface of the shaft 100. Is done. The shaft 100 is a shaft used as a transport roller for transporting a recording medium when the unevenness 110 rotates in contact with the surface of the recording medium in a copying machine, a printer, or the like.

As shown in FIG. 2A, the rolling die 10 has a plurality of first grooves 11 having a predetermined depth. These first grooves 11 are formed in a V shape. In addition, the rolling die 10 is a second groove between the first grooves 11 that is shallower than the first grooves 11 and has a wider groove area on the cross section than the first grooves 11. A groove 12 is provided. The second groove 12 is a groove having a flat bottom portion 12a. Here, the dimension W10 of the convex part 13 formed between the 1st groove | channel 11 and the 2nd groove | channel 12 of the rolling die ₁₀ is 0.05 mm, as shown in FIG. Moreover, the pitch P1 which is the space | interval of the 1st groove | channels 11 of the rolling die 10 is 0.34 mm. Although details will be described later, the relationship between the volume A of the first groove 11 and the volume B of the second groove 12 is A ≦ B.

On the other hand, as shown in FIG. 1, the rolling mold 20 is a mold that can freely contact and separate from the shaft 100. The rolling mold 20 has a predetermined depth as shown in FIG. A plurality of grooves 21 are provided. These grooves 21 are formed in a V shape. Here, the dimension W ₂₀ of the convex part 23 formed between the grooves 21 of the rolling mold ₂₀ is larger than the dimension W ₁₀ (0.05 mm) of the convex part 13 of the rolling mold 10. 0.08 mm. Moreover, the pitch P2 which is the space | interval of the grooves 21 of the rolling die 20 is 0.34 mm which is the same as the pitch P1.

  In order to form the unevenness 110 on the surface of the shaft 100 with such rolling molds 10 and 20, the rolling mold 20 is moved in the direction of arrow D as shown in FIG. , 20, the rolling mold 10, 20 is rotated in the direction of arrow A, the shaft 100 is rotated in the direction of arrow B, and the rolling mold 20 is moved in the direction of arrow C. Concavities and convexities 110 are formed on the surface of the shaft 100.

  FIG. 3 is a view showing a concavo-convex pattern on the shaft surface formed by the rolling mold shown in FIG. 1, and FIG. 4 is a perspective view showing a part of the concavo-convex on the shaft surface shown in FIG.

  FIG. 3 shows a pattern of the unevenness 110 formed by the rolling dies 10 and 20. The pattern of the concavo-convex 110 includes a first pattern row R1 composed of a quadrangular pyramid 111 having a flat top portion 111a formed by the second groove 12 of the rolling mold 10 and the groove 21 of the rolling mold 20. A pattern in which the second pattern row R2 composed of the quadrangular pyramids 112 having the projections 112a formed by the first grooves 11 of the rolling mold 10 and the grooves 21 of the rolling mold 20 are alternately arranged. It is. The unevenness 110 is four times higher than the height of the top portion 111a of the quadrangular pyramid 111 as shown in the AA cross section, the BB cross section shown in FIG. 3, and the perspective views shown in FIGS. 4A and 4B. The protrusion 112a of the pyramid 112 is higher and sharper. For this reason, when the both ends of the recording medium are pierced by the protrusion 112a, the recording medium is received by the top portion 111a, so that the recording medium can be reliably pierced by the protrusion 112a. Accordingly, the recording medium can be accurately and reliably conveyed by the shaft 100. Further, as seen in the AA cross section and the BB cross section shown in FIG. 3, every other protrusion 112a is formed, so that it is easy to pierce the recording medium even with a low load.

  FIG. 5 is a view showing a screw and its rolling die, which are representative rolling products employing the rolling method, and a fine projection roller having a conveying performance and its rolling die.

  FIG. 5A shows a rolling mold 1 for rolling a screw 2 that is a typical rolled product. When the convex part of the rolling mold 1 bites into the work surface of the rod-shaped shaft, half of the volume V1 of the shaft that the convex part bites forms half the volume V2 of the mountain on the work surface and approaches from both sides. As a result, a mountain is formed, and the screw 2 is formed.

  On the other hand, FIG. 5 (B) shows a rolling mold 3 for rolling the fine projection roller 4 having a conveying performance. When the convex part of the rolling mold 3 bites into the work surface of the rod-shaped shaft, half V1 of the volume of the shaft biting into the convex part forms half V2 of the mountain volume on the work surface and approaches from both sides. As a result, a mountain is formed, and the fine protrusion roller 4 is formed.

  Here, the screw 2 is formed in a smoothly continuous mountain shape, whereas the fine protrusion roller 4 having a conveyance performance pierces the recording medium (sheet), and does not slip and can feed the gear. In order to realize such high-precision conveyance, an arrangement as shown in FIG. 5B is necessary. In sheet conveyance, it is necessary to make it easy to pierce even under a low load. To that end, it is necessary to sharpen the tip of the protrusion and to make the angle of the mountain sharp, and it is also necessary to widen the arrangement interval. If the interval is too narrow, the number of peaks per unit area will increase, and under a constant load, the load on one mountain will be dispersed and reduced, making it difficult to stab the sheet and reducing performance. .

  As shown in FIG. 5, since the convex part of the rolling die 1 for rolling the screw 2 which is a typical rolled product is a small R shape, the shaft can be reduced with little resistance. Since the metal bites into the recesses of the rolling mold 1 smoothly because the metal bites into the metal and the angle is gentle (for example, 60 degrees), the fine protrusion roller 4 is rolled. Since the convex part of the rolling die 3 is wide and has a steep angle (for example, 50 degrees or less), it has a large biting resistance, which is an adverse condition for the metal flow.

  Next, the actual and limit of protrusion formation by the rolling manufacturing method will be described. As shown in FIG. 1, the formation of protrusions by rolling involves the interaction of rotation and pressure to bite a rolling die (die) into the metal surface and plastically deform the surface layer, thereby forming the groove shape of the die into a product. It is formed on the principle of transferring as a mountain shape.

  In the rolling process, as shown in FIG. 5B described above, as the width of the dimension A of the convex portion of the rolling mold increases, the resistance to bite into the metal increases, and the transfer limit (processing limit) is When the metal pushed away by the convex part of the rolling die no longer flows into the concave part, and the resistance further increases, only the shaft (work) is deformed and the transfer is not performed.

  Actually, as a result of testing with a stainless steel material (SUS303), there is a limit to the distance between the protrusions that can be formed even if the shape is difficult to deform (the width of dimension A in FIG. 5B is 0.4 mm). )

  FIG. 6 is a view showing a shaft having a shape that is easily deformed in the rolling method.

  FIG. 6A shows a cylindrical shaft 200. The shaft 200 is a relatively thin cylindrical shaft having an outer diameter D1 and an inner diameter D2. FIG. 6B shows a shaft 300 having a rod-shaped member 301 having an outer diameter D4, a thickness 302 provided on the outer periphery of the rod-shaped member 301, and a protruding portion 302 having an outer diameter D3. It is shown.

  As shown in FIG. 6, it is extremely difficult to form the protrusions 210 and 310 on the shafts 200 and 300 having a shape that is easily deformed by the influence of pressure, and there are some differences depending on conditions (material, thickness, diameter, brim thickness, etc.) Although there is a difference, when the width of the dimension A shown in FIG. 5B exceeds 0.2 mm, for example, the shape is deformed due to the pressure, and the formation of the protrusions becomes impossible.

  Here, by reducing the dimension A shown in FIG. 5B, the resistance to bite into the metal is reduced, so that the projection can be formed even with a shaft that is easily deformed. However, since the protrusions having the conveyance performance need to be spaced apart to some extent (for example, 0.2 to 0.5 mm), in the first embodiment, the dimension A is not uniformly reduced in FIG. 2A. A rolling mold 10 having the shape shown is employed. Here, the relationship between the volume A of the first groove 11 and the volume B of the second groove 12 is A ≦ B. The reason is that if the metal flows into and fills the second groove 12 that is the escape groove before the metal flows into and fills the first groove 11 that is the protrusion forming groove, the resistance causes This is because the metal does not bite into the metal and sharp protrusions are not formed. Here, the dimension A shown in FIG. 5B can be arbitrarily adjusted while maintaining the relationship between the volume A and the volume B (A ≦ B). The depth relationship between the first groove 11 (V-groove) and the second groove 12 (R-groove) is such that when the conveyance protrusion (sharp protrusion) is stuck in the sheet during sheet conveyance, In order to prevent the mountain formed by the groove 12 from becoming an obstacle, the step between the first groove 11 and the second groove 12 needs to be 0.02 mm or more.

  FIG. 7 is a perspective view of a rolling mold according to the second embodiment of the present invention, and FIG. 8 is a diagram showing an uneven pattern on the shaft surface formed by the rolling mold shown in FIG.

  FIG. 7 shows two rolling dies 10 that are the same as the rolling dies 10 shown in FIG. Here, the rolling mold 10 shown in FIG. 7A is referred to as a first rolling mold. Further, the rolling mold 10 shown in FIG. 7B is referred to as a second rolling mold. Between these first and second rolling molds, a shaft to be rolled is provided, and the shaft is pressed between the first and second rolling molds and rotated to rotate the shaft surface. The unevenness 120 shown in FIG. 8 is formed.

  FIG. 8 shows a pattern of unevenness 120 formed by the first and second rolling molds. The pattern of the unevenness 120 includes a quadrangular pyramid 121 having a flat top 121a formed by the second groove 12 of the first rolling mold and the first groove 11 of the second rolling mold, and A first pyramid 122 having a top 122a wider than the top 121a formed by the second groove 12 of the first rolling mold and the second groove 12 of the second rolling mold. It has a pattern row R1. Further, the pattern of the unevenness 120 includes a quadrangular pyramid 123 having protrusions 123a formed by the first groove 11 of the first rolling mold and the first groove 11 of the second rolling mold, and A second pattern row R2 composed of a quadrangular pyramid 124 having a flat top portion 124a formed by the second groove 12 of the first rolling mold and the first groove 11 of the second rolling mold. Have. The protrusions 123a of the unevenness 120 may pierce both ends of the recording medium and accurately and reliably convey the recording medium.

  FIG. 9 is a perspective view of a rolling die as a comparative example.

  9 shows two rolling molds 20 that are the same as the rolling mold 20 shown in FIG. Here, the rolling die 20 shown in FIG. 9A is referred to as a first rolling die, and the rolling die 20 shown in FIG. 9B is referred to as a second rolling die. Between these first and second rolling molds, a shaft to be rolled is provided, and the shaft is pressed between the first and second rolling molds and rotated to rotate the shaft surface. The first pattern row R1 made of the quadrangular pyramid 123 having the protrusion 123a shown in FIG. 8 and the unevenness made of the second pattern row R2 that is the same as the first pattern row are formed. For this reason, the interval between the protrusions 123a is narrow, and under a constant load, the weight applied to one protrusion 123a is dispersed and reduced, so that it is difficult to pierce the recording medium and the performance is deteriorated.

  Here, the following experiment was conducted. In this experiment, a shaft 300 having a brim-like protruding portion 302 shown in FIG. 6B is manufactured by SUS303, and the convex portion dimension A shown in FIG. 5 is 0.25 mm using the shaft 300. Protrusions were formed on both the rolling molds and the rolling molds of 0.12 mm, and the state of the protrusions and the amount of deformation were measured. When the convex dimension A is 0.25 mm, no protrusion is formed, the outer diameter is small (0.15 mm), and the shape is swelled right and left (0.12 mm), whereas the convex dimension A In the case of 0.12 mm, the projection was successfully formed. Further, the deformation (left and right bulges) of the dimension t of the portion 302 projecting into a collar shape was suppressed to 0.03 mm.

  Next, a test for verifying the formation of protrusions suitable for conveying a sheet to a work that is easily deformed is performed using the rolling mold of the first embodiment (see FIG. 1) and the rolling mold of the second embodiment (see FIG. 7). I did it. As a target work, a shaft having the shape shown in FIGS. 10 and 11 was used.

  FIG. 10 is a view showing a hollow cylindrical shaft, and FIG. 11 is a view showing a shaft having a protruding portion.

  A shaft 400 shown in FIG. 10 is a hollow cylindrical shaft having an outer diameter D1 and an inner diameter D2, which is a relatively thin wall. Here, the material of the shaft 400 is SUS430F. The outer diameter D1 is 20 mm, and the inner diameter D2 is 8 mm. The shaft 400 can be used for a copying machine or a large printer.

  On the other hand, a shaft 500 shown in FIG. 11 is a shaft 500 having a rod-like member 501 and a flange-like portion 502 having a thickness t and an outer diameter D3 provided on the outer periphery of the rod-like member 501. Here, the material of the shaft 500 is SUS430F. The thickness t is 2 mm, and the outer diameter D3 is 5 mm. In addition, as a use of this shaft 500, a small printer is mentioned.

  When forming the irregularities 410 and 510 on the shafts 400 and 500 as the target workpiece, when the rolling mold 3 shown in FIG. 5 is used, both are deformed by pressure when the projection A is 0.25 mm or more. Protrusion formation was impossible. On the other hand, when the rolling dies of the first and second embodiments were used, the projections and depressions shown in FIG. 3 and the projections and depressions shown in FIG. 8 could be easily formed.

  Further, the outer diameter portion excluding the unevenness 410, the inner diameter D2, and the length of the shaft 400 were not changed by the rolling process.

  On the other hand, the change in the outer diameter D3 of the shaft 500 was not measurable because the unevenness 510 was formed on the entire surface. Further, regarding the thickness t, although it swelled by 0.006 mm, there was no problem in terms of component accuracy.

  For the protrusion patterns formed on the shafts 400 and 500, the BB cross section shown in FIGS. 3 and 8 is tangent to the sheet to be conveyed (axial direction), and the AA cross section is conveyed (circumferential direction). Direction (may be reciprocally conveyed).

  3 and FIG. 8 have the same arrangement when viewed in the BB cross section and the AA cross section, the number of sharp protrusions (conveyance protrusions) varies.

  As for the conveyance performance of both patterns, the pattern shown in FIG. 3 has a large number of protrusions per area, and the rotation angle from one conveyance protrusion to the next conveyance protrusion is extremely small. This is suitable for applications that require a relatively high load and require ultra-high precision conveyance.

  On the other hand, the pattern shown in FIG. 8 has been formed on a workpiece having a shape that is difficult to deform, since the intervals (pitch) of the conveying protrusions in the axial direction and the radial direction are arranged in a uniform manner. Equivalent use (printer etc.) and performance can be obtained.

It is a figure which shows a mode that an unevenness | corrugation is formed in the shaft surface with the rolling die of 1st Embodiment of this invention. It is a figure which shows a part of cross section of the rolling die shown in FIG. It is a figure which shows the uneven | corrugated pattern of the shaft surface formed with the rolling die shown in FIG. It is a perspective view which shows a part of unevenness | corrugation of the shaft surface shown in FIG. It is a figure which shows the screw | thread which is a typical rolling processed product which employ | adopted the rolling processing method, its rolling die, the roller for fine protrusions which has conveyance performance, and its rolling die. It is a figure which shows the shaft which has a shape which is easy to deform | transform in a rolling method. It is a perspective view of the rolling die of 2nd Embodiment of this invention. It is a figure which shows the uneven | corrugated pattern of the shaft surface formed with the rolling die shown in FIG. It is a perspective view of the rolling die as a comparative example. It is a figure which shows a hollow cylindrical shaft. It is a figure which shows the shaft which has the part protruded in the shape of a collar.

Explanation of symbols

1, 3, 10, 20 Rolling mold 2 Screw 4 Fine projection roller 11 First groove 12 Second groove 12a Bottom portion 13, 23 Convex portion 21 Groove 23 Convex portion 100, 200, 300, 400, 500 Shaft 110, 120, 410, 510 Concavity and convexity 111a, 121a, 122a, 124a Top 111, 112, 121, 122, 123, 124 Square pyramid 112a, 123a, 210, 310 Protrusion 301, 501 Bar-shaped member 302, 502 Overhanging portion

Claims (3)

In the rolling process method of forming irregularities on the surface of the shaft by rotating by pressing the shaft to be rolled with a plurality of rolling dies,
A plurality of first grooves having a predetermined depth are provided, and the first grooves are shallower than the first grooves between the first grooves, and the area of the grooves on the cross section is the first grooves and the first grooves. A rolling method comprising rotating a shaft while pressing the shaft with a plurality of rolling dies including at least one rolling die having the same or a second groove wider than the first groove.   2. The rolling method according to claim 1, wherein the first groove is a groove formed in a V shape, and the second groove is a groove having a flat bottom. At least one rolling die among a plurality of rolling dies for forming irregularities on the surface of the shaft by pressing and rolling the shaft to be rolled,
A plurality of first grooves of a predetermined depth;
A second groove formed between the first grooves and shallower than the first grooves and having the same area as the first grooves or wider than the first grooves. A rolling mold characterized in that a groove is formed.

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