JP2006247742A - Method for manufacturing shaft, shaft manufactured by the same and guide shaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shaft product which is very small in a dimensional error by bending a metallic sheet. <P>SOLUTION: This shaft manufacturing method is provided with a step where the metallic sheet 500 is placed on a die unit provided with a main die 100 having a recess 110 and a pair of the side dies 200 which are arranged on both sides of the recess 110 and slidable to the main die 100, a step where the metallic sheet 500 is pressed toward the recess 110 of the main die 100 by making a punch 400 to approach the main die 100 and a step where the metallic sheet 500 is pressed against the side faces of the punch 400 by sliding a pair of the side dies 200 by making a pair of cam drivers 300 to approach the respective of a pair of the side dies 200 after the metallic sheet 500 is pressed toward the recess with the tip of the punch 400. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a shaft. More specifically, the present invention relates to a shaft manufactured by bending a metal plate and a manufacturing method thereof.

  Devices that handle two-dimensional images include products that include members that move linearly. Specific examples include a line sensor in a copying apparatus or an optical reading apparatus, a recording head in a recording apparatus, and the like. It is important that this type of member does not move in a direction other than the moving direction when moving, and therefore has a structure that is accurately linear and supported by a smooth guide member on the surface. Often taken.

  As the guide member as described above, shaft products manufactured by cold forging, drawing, or cutting are used with emphasis on the accuracy of the surface shape. There is a problem that it is expensive and its own weight is large.

On the other hand, Patent Document 1 below proposes to provide a lightweight and inexpensive shaft product by pressing.
Japanese Utility Model Publication No. 04-094113

  However, for example, when manufacturing a guide shaft having a U-shaped cross section, a desired part accuracy may not be achieved even if a simple press working is performed using a mold having a shape complementary to the product. Further, there are cases where the required accuracy can be achieved by repeating the bending process for one member, but since the number of manufacturing steps increases, the advantage of cost reduction is diminished.

  In order to solve the above-mentioned problem, according to the first embodiment of the present invention, a shaft manufacturing method for manufacturing a shaft having a U-shaped cross-section perpendicular to the longitudinal direction by bending a metal plate, wherein And a step of placing a metal plate on a die unit having a side die that is arranged on both sides of the recess and slidable with respect to the main die, on the open side of the recess in the main die, and The step of bringing the punch close to the main die and pressing the metal plate toward the recess of the main die at the tip of the punch, and as the punch approaches the main die, the pair of cam drivers is moved to the pair of sides. A step of sliding a pair of side dies with a pair of cam drivers by approaching each of the side dies, and pressing the metal plate against the side surface of the punch after the tip of the punch presses the metal plate against the recess Shaft manufacturing with The law is provided. Thereby, the axis | shaft which has a highly accurate U-shaped cross section can be manufactured in one processing process.

  Further, according to one embodiment, in the shaft manufacturing method, each of the side dies has a main direction in which the side die slides as the punch moves away from the recess in the direction in which the punch approaches the recess in the main die. Protrusions projecting from the recessed side of the die. This compensates for the displacement of the shape due to the springback of the material, and enables high-precision processing in one process.

  Moreover, according to the 2nd form of this invention, the axis | shaft which has the U-shaped cross section manufactured with the said axis | shaft manufacturing method is provided. This provides a shaft product that is lightweight and low-cost while having shape accuracy comparable to the metal shaft of Muku manufactured by cutting or the like.

  According to the third aspect of the present invention, there is provided a guide shaft manufactured by the above-described shaft manufacturing method, wherein the guide shaft slides an optical element in an optical reader that optically reads information printed on a document. Provided. Further, according to the fourth aspect of the present invention, in the optical reading device that optically reads the information printed on the document, the guide shaft slides the optical element, and the cross section perpendicular to the sliding direction has a U shape. A guide shaft is provided. Thereby, the optical reader can be reduced in weight and cost can be reduced.

  The above summary of the invention does not enumerate all the necessary features of the present invention, and sub-combinations of these feature groups can also be the invention.

  Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the claimed invention, and all combinations of features described in the embodiments are included. It is not necessarily essential for the solution of the invention.

  FIG. 1 is a perspective view showing a U-shaped shaft manufactured by pressing a metal plate 500 by a press apparatus described later. As shown in the figure, this shaft is formed integrally with an arcuate surface portion 510 having an arcuate cross section and a pair of flat rib portions 520 at a boundary C to form a U-shaped cross section as a whole. Axis.

  Here, the cross section of the arcuate surface portion 510 depicts a semicircular arc having an inner angle of 180 °, and there are very few errors with respect to a perfect circular arc. On the other hand, each of the rib portions 520 maintains a flat shape with no undulations, and there is no warpage or the like in the vicinity of the boundary C. The rib portions 520 are parallel to each other over the entire length and the entire width, and the distance between them is constant.

  FIG. 2 is a cross-sectional view showing the structure of the press apparatus 10 used for manufacturing the shaft. The figure also shows the initial steps of shaft manufacture.

  2 is a cross-sectional view of the press device 10 cut along a plane perpendicular to the longitudinal direction of the shaft shown in FIG. Therefore, each member has a cross-sectional shape shown in the drawing and continuously extends in the depth direction of the drawing.

  As shown in the figure, the press device 10 includes a main die 100 having a depression 110 at the center of the upper surface, a pair of side dies 200 placed on both sides of the depression 110 on the upper surface of the main die 100, It is mainly formed from a pair of cam drivers 300 disposed behind each side die 200 and a punch 400 disposed above the recess 110 of the main die 100. Further, in this figure, a metal plate 500 as a material is placed across the pair of side dies 200.

  In the press device 10, a through-hole 120 that penetrates the main die 100 vertically is provided below the cam driver 300. Thereby, the cam driver 300 which descend | falls no longer interferes with the main die | dye 100 in the step mentioned later.

  Further, the side dies 200 are pushed by the cam driver 300 from behind and slide so as to be close to each other on the upper surface of the main die 100. Here, when the side dies 200 come close to each other, a shape that is substantially complementary to the outer die of the U-shaped shaft is formed together with the recess 110 of the main die 100. Details of the shape will be described later. .

  Each of the pair of cam drivers 300 includes two inclined surfaces (cam surfaces) on opposite surfaces. That is, the cam driver 300 includes a shoulder portion 310 at the lower end of the facing surface and a step portion 320 formed slightly above. When the cam driver 300 descends, the side die 200 slides horizontally by being pushed by the shoulder portion 310 and the step portion 320. Note that the pair of cam drivers 300 descends simultaneously with the same amount of descent.

  Each side die 200 has side surfaces facing each other as pressing surfaces 220 against the workpiece. Further, inclined shoulder portions 230 are formed at the upper end of the rear end surface opposite to the pressing surface 220, respectively. As the shoulder portion 230 abuts and slides on the shoulder portion 310 or the step portion 320 of the cam driver 300, the side die 200 moves horizontally so as to be close to each other.

  FIG. 3 is a view showing a single shape of the side die 200 used by being mounted on the press apparatus 10 shown in FIG. As already described, the side die 200 slides on the upper surface of the main die 100 and presses the metal plate 500 horizontally by the pressing surface 220 which is the side surface thereof. The shoulder 210 at the upper end of the pressing surface 220 has a shape that is smoothly continuous from the upper surface of the side die 200, and when the punch 400 starts to reduce the metal plate 500, a large pressure is locally generated and the metal plate 500. It is formed so as not to damage the lower surface of the.

  4 is an enlarged view of a region surrounded by a dotted line A in FIG. A dotted line 250 indicates the outer side surface shape of the U-shaped shaft obtained after the metal plate 500 is processed. That is, the portion below the boundary C forms an arc corresponding to the arc surface portion 510, and the portion above the boundary C is a vertical straight line except for the shoulder portion 210.

  On the other hand, in the pressing surface 220, the region below the shoulder portion 210 and above the boundary C forms an inclined surface that is further away from the dotted line 250 toward the lower side, and the lower end of the shoulder portion 210 is the dotted line 250 most. Protrusions close to. On the other hand, in the region below the boundary C, the arc shape itself is the same as the dotted line 250 although it is separated from the dotted line 250 due to the inclination described above. By pressing from the side with the side die 200 having such a shape, the portion of the metal plate 500 corresponding to the rib portion 520 is moved 90 ° from the horizontal plane before bending in the region above the boundary C. Can be bent over.

  That is, when the bending process is finished and the side die 200 is released from being pressed, the rib portions 520 of the metal plate 500 are slightly spread away by the spring back. However, the excessive bending and the spring back are offset by performing the excessive bending as described above. Therefore, by appropriately setting the inclination of the pressing surface 220, bending can be performed so that the amount of bending in the final product is accurate.

  The punch 400 has an arc surface 410 having the same shape as the inner surface of the arc surface portion 510 of the shaft shown in FIG. The punch 400 is positioned above the hollow portion 110 of the main die 100 before the machining is started, and is lowered so as to be close to the hollow portion 110 when the machining is started. Therefore, when the punch 400 is lowered while the metal plate 500 as the workpiece is placed on the side die 200 as shown in the drawing, the metal plate 500 is pressed down by the arc surface 410 at the lower end of the punch 400. It bends and finally comes into contact with the bottom of the recess 110.

  FIG. 5 is a diagram showing the shape of the punch 400 alone. As shown in the figure, the punch 400 includes an arc surface 410 formed at the lower end and a neck portion 420 that supports the arc surface 410 from above. The arc surface 410 has a shape complementary to the inner surface shape of the arc surface portion 510 of the U-shaped shaft shown in FIG. 1, and has a cylindrical shape with an inner angle of approximately 180 °.

  In contrast, the neck portion 420 has a tapered cross-sectional shape that decreases in width as the distance from the arc surface 410 increases. Thereby, when the above-mentioned side die 200 presses the metal plate 500 from the side and performs an excessive bending process, a room for deformation of the edge portion of the metal plate 500 is formed.

  FIG. 6 is an enlarged view showing a portion surrounded by a dotted line B in FIG. As shown in the figure, a fine projection 430 is formed at the boundary C between the arcuate surface 410 at the tip of the punch 400 and the neck 420 above it.

  When the side punch 400 presses the rib portion 520 of the metal plate 500 from the side, the projection 430 applies a pressure larger than that of the other region to the inside of the metal plate 500. Thereby, the spring back in the boundary area | region of the circular arc surface part 510 which makes a curved surface in the metal plate 500, and the flat rib part 520 is suppressed strongly. Therefore, each area | region of the circular arc surface part 510 which has a fixed curvature, and the rib part 520 which is not bent at all is shape | molded with high precision separately.

  FIG. 7 is a diagram showing a next step of bending the metal plate 500 by the press device 10 formed as described above. In addition, the same referential mark is attached | subjected to the same component as FIG. 2, and the overlapping description is abbreviate | omitted.

  As shown in the figure, when the punch 400 descends, the pair of cam drivers 300 also descend simultaneously. Therefore, the shoulder 310 of the cam driver 300 and the rear shoulder 230 of the side die 200 slide with each other, and the pair of side dies 200 move horizontally so as to be close to each other. However, at this time, the side die 200 is only in contact with the metal plate 500 and has not yet been involved in active processing by pressing from the side. Accordingly, a slight gap remains between the metal plate 500 and the neck portion 420 of the punch 400.

  FIG. 8 is a diagram illustrating a final step of processing by the press device 10. 2 and FIG. 7 are assigned the same reference numerals, and duplicate descriptions are omitted.

  As shown in the figure, in this step, the pair of cam drivers 300 further descends. Therefore, each side die 200 is pushed from the rear by the step portion 320 of each cam driver 300. For this reason, the pressing surfaces 220 of the side dies 200 are closer to each other and press both edge portions of the metal plate 500 toward the neck portion 420 of the punch 400. Therefore, in this region, the metal plate 500 is bent with a processing amount exceeding 90 °.

  However, as described above, when the metal plate 500 is released from the punch 400, the main die 100, and the side die 200, the metal plate 500 slightly returns to the shape before processing by the spring back. As a result, the rib portion 520 of the metal plate 500 is finally bent by 90 ° with respect to the original metal plate 500.

  Thus, the shaft manufactured through the steps shown in FIGS. 2, 7, and 8 has a highly accurate shape. Specifically, an electrogalvanized cold-rolled steel sheet (SECC) having a thickness of 0.5 mm is used as a material, and an axis having an inner diameter of the arcuate surface portion 510 of 7 mm, a height of the rib portion 520 of 4 mm, and a total length in the longitudinal direction of 360 mm. Manufactured. Further, in the used punch 400, the thickness of the projection 430 in the horizontal direction was set to 0.1 mm. The obtained shaft had an overall warpage of 0.1 mm or less and a local deformation of 0.05 mm or less. Further, the maximum variation of the arcuate surface portion 510 was 0.025 mm.

  As described above, the highly accurate shaft can be used as, for example, a guide shaft that supports and guides the line sensor in an optical reading device with high resolution. Therefore, when an optical reading device in which the above-described shaft was incorporated as a guide shaft was actually assembled and operated, the line sensor slid smoothly and the obtained image information was not disturbed. In addition, it exhibited satisfactory performance in terms of vibration, sliding noise, and wear resistance during sliding.

  As described in detail above, according to the present invention, a U-shaped shaft product manufactured by bending a metal plate is manufactured with high accuracy comparable to a shaft product manufactured by cold forging, drawing, cutting, or the like. it can. This shaft product can be used in place of the shaft product manufactured by cold forging, drawing, cutting, etc., so in the equipment that had to use solid material by cutting due to the limit of part accuracy , Greatly contribute to reducing cost and weight.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

The perspective view which shows the U-shaped axis | shaft manufactured by bending the metal plate 500. FIG. Sectional drawing which shows the structure of the press apparatus 10 which can manufacture the axis | shaft shown in FIG. The figure which shows the shape of the side die | dye 200 mounted | worn with and used for the press apparatus 10. FIG. The figure which shows the further detailed shape of the side die | dye 200. FIG. The figure which shows the shape of the punch 400 used with the press apparatus 10. FIG. The figure which shows the further detailed shape of the punch 400. FIG. Sectional drawing which shows one step of the process by the press apparatus. FIG. 4 is a cross-sectional view showing the final step of processing by the press device 10.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Press apparatus, 100 Main die, 110 Indentation part, 120 Through hole, 200 Side die, 210, 230, 310 Shoulder part, 220 Press surface, 300 Cam driver, 320 Step part, 400 Punch, 410 Arc surface, 420 Neck Part, 430 protrusion part, 500 metal plate, 510 arc surface part, 520 rib part

Claims (5)

A shaft manufacturing method for manufacturing a shaft having a U-shaped cross section perpendicular to the longitudinal direction by bending a metal plate,
The metal plate is attached to a die unit including a main die having a depression and a side die disposed on both sides of the depression on the open side of the depression in the main die and slidable with respect to the main die. A placing step;
A step of bringing a punch close to the main die and pressing the metal plate toward the depression of the main die at the tip of the punch; and
As the punch approaches the main die, the pair of cam drivers approach each of the pair of side dies, thereby causing the pair of cam drivers to slide the pair of side dies. And a step of pressing the metal plate against a side surface of the punch after the tip of the punch presses the metal plate toward the recess.   Each of the side dies protrudes from the indentation side of the main die in the direction in which the side die slides as the punch moves away from the indentation in the direction of approaching the indentation of the main die. The shaft manufacturing method of Claim 1 which has a protrusion part.   A shaft having a U-shaped cross section manufactured by the shaft manufacturing method according to claim 1.   A guide shaft for sliding an optical element in an optical reading device that optically reads information printed on a document, and the guide shaft manufactured by the shaft manufacturing method according to claim 1.   A guide shaft that slides an optical element in an optical reading device that optically reads information printed on a document, and has a U-shaped cross section perpendicular to the sliding direction.

Images