JP4827562B2 - Method for manufacturing rolling dies - Google Patents

Description

  The present invention relates to a method for manufacturing a rolling die, and more particularly, to a method for manufacturing a rolling die that can reduce the processing cost and can manufacture the rolling die at a low cost.

  When a bolt and a nut are fastened, fastening by a so-called double nut method is generally used as a means for preventing the nut from loosening. In this case, by using a double screw bolt having a double screw in which a coarse screw and a fine screw having different leads coexist, a function of preventing the loosening by the double nut method is also performed.

By the way, the double screw is generally formed by rolling. For example, in the technique described in Japanese Patent Application Laid-Open No. 2003-260532, a coarse male thread forming protrusion (coarse thread forming tooth profile) and a fine male thread forming protrusion (fine thread) are formed on the rolling surface of a die (rolling die). The thread forming tooth profile) is ground in a state of crossing each other, and the rolled material is rolled on the rolling surface of the die to roll a double screw on the outer peripheral surface of the rolled material. .
JP 2003-260532 A (paragraph [0054], FIG. 10 etc.)

  However, in the above-described die, it is necessary to grind the coarse male screw forming ridge and the fine male screw forming ridge over the entire rolling surface of the die. There is a problem that it cannot be manufactured at low cost.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a method for manufacturing a rolling die that can reduce a processing cost and manufacture a rolling die at a low cost. .

In order to achieve this object, a method for manufacturing a rolling die according to claim 1 includes a coarse thread forming tooth profile for forming a coarse thread and a fine thread forming tooth profile for forming a fine thread. A rolling screw having a rolling tooth profile surface, rolling the material to be rolled on the rolling tooth profile surface, and a double screw in which coarse screws and fine screws having different leads coexist on the outer peripheral surface of the rolling material. A rolling step for rolling on a die material a shaft- shaped member formed on the outer peripheral surface and formed with a double screw in which a coarse screw and a fine screw with different leads coexist, and the rolling step prior to, and a grinding step for grinding the rough screw to the die material, the by rolling process was bite into the outer peripheral surface of the shaft-like member to said die material, the coarse thread forming teeth on the die material And the fine thread forming tooth profile are rolled and polished by the grinding process. The rough screw to be cut is formed such that the bottom surface of the valley is formed into a flat surface, and the bottom surface of the valley formed in the flat surface is located at substantially the center of the flank that connects the crest and valley bottom of the fine thread forming tooth profile, The flank is formed in a shape corresponding to the flank of the coarse thread forming tooth profile .

  According to the method for rolling a rolling die according to claim 1, a rolling step of rolling on a die material a shaft-like member on which a double screw in which coarse screws and fine screws having different leads coexist is formed. In the rolling process, the outer peripheral surface of the shaft-shaped member is bitten into the die material, and the coarse thread forming tooth profile for forming the coarse thread and the fine thread forming tooth profile for forming the fine thread, and Is rolled into a die material.

  Here, in the conventional method for manufacturing a rolling die, the entire rolling surface of the die material is ground to form a coarse thread forming tooth profile and a fine thread forming tooth profile. As a result, the processing cost increases, and the rolling die cannot be manufactured at a low cost.

  On the other hand, according to the present invention, by rolling a shaft-shaped member on which a double screw is formed on a die material, a coarse thread forming tooth profile and a fine screw forming tooth profile are rolled on the die material. To do. That is, since it is only necessary to grind only the outer peripheral surface of the shaft-like member, the machining area of the grinding can be reduced as compared with the case where grinding is performed on the entire rolling surface of the die material. As a result, there is an effect that the processing cost can be reduced and the rolling die can be manufactured at a low cost.

  Further, according to the present invention, since the coarse thread forming tooth profile and the fine thread forming tooth profile are formed by plastic deformation, the work surface is cured and the strength is improved. As a result, compared with the conventional case where the coarse thread forming tooth profile and the fine thread forming tooth profile are formed by grinding, the coarse thread forming tooth profile and the fine thread forming tooth profile are improved in strength. There is an effect that the life of the rolling die can be increased.

Further, according to the present invention, before the rolling step, the die material is provided with a grinding step for grinding the rough screw, and the shape of the rough screw to be ground by the grinding step is such that the bottom surface of the valley is for coarse screw formation. It is located on the top side of the peak from the bottom of the valley of the tooth profile, and the flank is formed in a shape that corresponds to the flank of the coarse thread forming tooth profile. The coarse screw is formed and plastically deformed by a shaft-shaped member, and the coarse thread forming tooth profile and the fine thread forming tooth profile are rolled.

  That is, the amount of plastic deformation of the die material can be reduced as compared with the case of rolling the coarse thread forming tooth profile and the fine thread forming tooth profile without previously forming the rough thread by grinding. It is easy to manufacture, and there is an effect that the coarse thread forming tooth profile and the fine thread forming tooth profile can be formed with high efficiency.

  Furthermore, since the amount of plastic deformation of the die material can be reduced, there is an effect that the load applied to the shaft-like member can be reduced and the life of the shaft-like member can be increased accordingly.

  Further, since the flank of the rough screw is formed in a shape corresponding to the flank of the coarse thread forming tooth profile, the shaft member is rolled to rotate the coarse thread forming tooth profile and the fine thread forming tooth profile. When manufacturing, the rough screw serves as a guide, and the shaft-like member can be rolled at an appropriate rotation pitch. As a result, there is an effect that the shape of the coarse thread forming tooth profile and the fine thread forming tooth profile can be formed with high accuracy.

  Further, in the conventional rolling die manufacturing method, the coarse thread forming tooth profile and the fine thread forming tooth profile are formed by grinding, that is, the fine thread forming tooth profile is formed on the valley bottom side of the coarse thread forming tooth profile. Therefore, the grinding process becomes complicated and the processing cost increases.

  On the other hand, according to the present invention, it is not necessary to form a fine thread forming tooth profile simply by forming a rough screw, so that a complicated grinding process is not required for the die material, and the processing cost is reduced accordingly. There is an effect that reduction can be achieved.

  Further, since the bottom surface of the valley of the rough screw is formed as a flat surface, the processing is facilitated, and the processing cost can be reduced correspondingly.

  Further, when the fine thread forming tooth profile is formed by grinding, it is necessary to grind with a tapered grindstone, so that the tip of the grindstone is easily chipped and the tool life of the grindstone is shortened. Then, since it is not necessary to form the fine thread forming tooth profile on the die material, there is an effect that it is possible to suppress an increase in processing cost due to damage to the grindstone.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings. FIG. 1 is a diagram illustrating a rolling die 1 according to an embodiment of the present invention, FIG. 1 (a) is a top view of the rolling die 1, and FIG. 1 (b) is a rolling die. 1 is a side view of FIG.

  In addition, in Fig.1 (a), while showing the crest line of the 1st process tooth 31 with a continuous line, the crest line of the 2nd process tooth 32 is illustrated with the wavy line. Further, in FIG. 1A, for easy understanding, illustration of the valley bottom lines of the first and second machining teeth 31 and 32 is omitted, and the biting angle and the clearance angle are greatly illustrated. .

  First, the overall configuration of the rolling die 1 will be described with reference to FIG. The rolling die 1 is formed by subjecting the outer peripheral surface of a cylindrical rolled material to plastic deformation, and rolling a double screw in which coarse screws and fine screws having different leads coexist by rolling. It is a tool for manufacturing a bolt (not shown).

  FIG. 1 shows one rolling die 1 fixed to a rolling machine (not shown) out of the pair of rolling dies 1, and is parallel to the one rolling die 1. The illustration of the other rolling die 1 to be moved is omitted.

  As shown in FIG. 1, the rolling die 1 is formed in a substantially rectangular parallelepiped shape from a metal material such as alloy tool steel or high-speed tool steel suitable for rolling, and its upper surface side (FIG. 1 (a) paper surface. On the front side, the upper side of FIG. 1 (b), a rolling tooth profile surface 2 for rolling a double screw is provided on the outer peripheral surface of the material to be rolled.

  As shown in FIG. 1, the rolling tooth profile surface 2 has a biting portion 21 and a finish portion 22 from the rolling direction starting end side (right side in FIG. 1) to the terminal end side (left side in FIG. 1). And the escape part 23 is continuously provided in order.

  In addition, as shown in FIG. 1 (a), two types of processing teeth 31, 32 (first processing teeth) are formed on the rolling tooth profile surface 2 constituted by the biting portion 21, the finishing portion 22, and the clearance portion 23. 31 and a plurality of second processing teeth 32) are respectively provided.

  The 1st processing tooth 31 is a screw thread for forming a coarse thread, and as shown in Drawing 1 (a), it ends from the starting end (the right side of Drawing 1 (a)) of rolling tooth profile surface 2 (Drawing 1). (B) It is formed continuously toward the left side, and is inclined at a predetermined lead angle with respect to the longitudinal direction of the rolling die 1 (left-right direction in FIG. 1). In the present embodiment, the lead angle of the first machining tooth 31 is set to 3 ° 10 ′, and the pitch (distance between two points corresponding to each other of the first machining teeth 31 adjacent to each other) is 1. It is set to 5 mm.

  The second working tooth 32 is a thread for forming a fine screw, and is formed continuously from the start end to the end of the rolling tooth profile surface 2 as shown in FIG. It is configured to be inclined at a predetermined lead angle with respect to the longitudinal direction of the die 1. In the present embodiment, the lead angle of the second machining tooth 32 is set to 1 ° 33 ', and the pitch is set to 0.75 mm.

  The biting portion 21 is a portion for biting the rolling tooth profile surface 2 on the outer peripheral surface of the material to be rolled, and is used as a so-called biting portion. As shown in FIG. 1 (b), the biting portion 21 is formed to rise and incline at a predetermined inclination angle from the start end (right side of FIG. 1 (b)) to the end end (left side of FIG. 1 (b)). Has been.

  The finishing portion 22 is a portion for finishing the double screw rolled into the material to be rolled by the biting portion 21, and as shown in FIG. 1 (b), the support surface (FIG. 1) of the rolling die 1. (B) It is formed substantially parallel to the lower surface.

  The escape portion 23 is a portion for discharging the rolled material finished by the finishing portion 22 from the rolling tooth profile surface 2, and is used as a so-called escape portion. As shown in FIG. 1B, the escape portion 23 is formed to be inclined downward at a predetermined inclination angle from the start end (right side of FIG. 1B) to the end end (left side of FIG. 1B). ing.

  Next, the details of the shaft-like member 50 will be described with reference to FIG. FIG. 2A is a front view of the shaft-shaped member 50, and FIG. 2B is a partially enlarged view of the shaft-shaped member 50. In FIG. 2B, the length of the shaft member 50 in the longitudinal direction (the length in the left-right direction in FIG. 2B) is omitted in order to simplify the drawing and facilitate understanding.

  The shaft-shaped member 50 is a tool for plastically deforming the rolling surface of the die material and rolling the first and second machining teeth 31 and 32 (see FIG. 1) by rolling. As shown in FIG. 2A, the shaft-like member 50 is formed in a substantially cylindrical shape from a metal material such as alloy tool steel or high-speed tool steel, and has a double screw 51 on its outer peripheral surface. It is configured.

  The shaft-shaped member 50 has shaft support holes (not shown) drilled in both end surfaces in the longitudinal direction (FIG. 2 (a), both end surfaces in the left-right direction), and is rolled through the shaft support holes. It is configured to be pivotally supported by a board (not shown). Moreover, in this Embodiment, while the shaft-shaped member 50 is comprised with alloy tool steel (SKD11), hardness is set to HRC60.

  The double screw 51 is a part formed in the same shape as the double screw bolt manufactured (rolled) by the rolling die 1 and is formed in a state where the coarse screw 52 and the fine screw 53 intersect each other. ing. That is, the fine screw 53 extends across the coarse screw 52 as shown in FIG.

  In manufacturing the shaft-shaped member 50, first, the outer peripheral surface of a columnar member made of a metal material such as alloy tool steel or high-speed tool steel is ground, and a coarse screw 52 (in this embodiment, Lead angle: 3 ° 10 ′, pitch: 1.5 mm). Then, the outer peripheral surface of the cylindrical member on which the coarse thread 52 is formed is ground again, and fine threads 53 (in this embodiment, a lead angle: 1 ° 33 ′, a pitch: 0.75 mm) are provided. Form. Thereby, the double screw 51 comprised by the coarse screw 52 and the fine screw 53 is formed. Finally, the columnar member on which the double screw 51 is formed is subjected to heat treatment, and the shaft-shaped member 50 is manufactured.

  Next, a method for rolling the rolling die 1 will be described with reference to FIGS. 3 and 4. FIG. 3A to FIG. 3D are partial cross-sectional views of the tooth profile surface 12 before rolling by the shaft-like member 50. 4 (a) to 4 (d) are partial cross-sectional views of the rolling tooth profile surface 2 taken along lines IVa-IVa to IVd-IVd in FIG. 1 (a), respectively.

  3A to 3D correspond to cross-sectional views taken along the line IVa-IVa to IVd-IVd in FIG. 1A, respectively. Further, in FIG. 3, for easy understanding, the thread shape of the second machining tooth 32 after rolling by the shaft-like member 50 is illustrated by a broken line. Moreover, in FIG. 4, in order to understand easily, the thread form of the 2nd process tooth 32 is virtually illustrated using the dashed-two dotted line. 3 and 4, the thread shapes of the first and second machining teeth 31 and 32 are illustrated at an acute angle, but the peaks and valleys are flat and curved.

  When manufacturing the rolling die 1 (see FIG. 1), first, a die material made of a metal material such as alloy tool steel or high-speed tool steel is cut into a substantially rectangular parallelepiped shape. And as shown in FIG. 3, the tooth profile surface 12 is formed by grinding to the one surface side of the die raw material cut | disconnected by the substantially rectangular parallelepiped shape, and forming the rough screw 4 (grinding process).

  The tooth profile surface 12 includes a chamfered portion, a finish portion, and a relief portion. The biting angle and clearance angle of the tooth profile surface 12 are set to be the same as the biting angle and clearance angle of the rolling tooth profile surface 2.

  The rough screw 4 has a flank shape corresponding to the flank of the first processing tooth 31 (see FIG. 4). Further, the rough screw 4 is formed so that the bottom surface of the valley is positioned at the approximate center of the flank connecting the top and bottom of the second machining teeth 32.

  That is, as shown in FIG. 3, the total area surrounded by the bottom surface of the rough screw 4 and the broken line below the bottom surface of the rough screw 4 (the lower side in FIG. 3) is the bottom surface of the rough screw 4. It becomes equal to the sum total of the area surrounded by the broken line on the upper side (upper side in FIG. 3) of the root surface of the rough screw 4. Thereby, in the rolling process to be described later, the shaft-like member 50 bites into the bottom surface of the root of the rough screw 4, and the second machining teeth 32 are formed by surging up by the bite.

  Next, the shaft-shaped member 50 (see FIG. 2) is rolled on the rolling tooth profile surface 2 on which the rough screw 4 is formed, and the rolling tooth profile surface 2 is subjected to a rolling process. As a result, the shaft-shaped member 50 bites into the bottom surface of the rough screw 4 so that the shaft member 50 is surrounded by the portion below the bottom surface of the rough screw 4 (the bottom surface of the rough screw 4 and the broken line below the bottom surface). As shown in FIG. 4, a double screw in which the first and second processing teeth 31 and 32 coexist is formed (rolling step).

  As described above, since the second processed tooth 32 subjected to the rolling process has a pitch that is half that of the first processed tooth 31, the second processed tooth 32 in the rolling direction (the left-right direction in FIG. 4). Each time the phase is shifted by 360 °, the second machining tooth 32 crosses the first machining tooth 31.

  As a result, as shown in FIG. 4, the second machining teeth 32 gradually change as the cross-sectional area located between the flanks of the adjacent first machining teeth 31 shifts in phase in the rolling direction. The second machining tooth 32 is formed at a depth position where the bottom of the second machining tooth 32 coincides with the bottom of the first machining tooth 31.

  The die material after passing through the rolling process is subjected to a predetermined quenching process in the quenching process. By completing the quenching process, the production of the rolling die 1 is completed.

  As described above, according to the present embodiment, the double screw 51 engraved on the outer peripheral surface of the shaft-like member 50 in the rolling process is made to bite into the bottom surface of the rough screw 4 and the bottom of the rough screw 4 is The first and second processing teeth 31 and 32 are formed by subjecting the surface to rolling and plastic deformation.

  Here, in the conventional method for manufacturing a rolling die, the first and second machining teeth 31 and 32 are formed by grinding, that is, the second machining teeth 32 arranged on the valley side of the first machining teeth 31 are formed. In order to form it, a complicated grinding process is required, and the processing cost increases accordingly.

  On the other hand, according to the present invention, it is not necessary to form the second machining teeth 32 only by forming the rough screw 4, so that complicated grinding work is not required for the die material, and the machining cost is correspondingly reduced. Can be reduced.

  Furthermore, as shown in FIG. 3, since the bottom surface of the rough screw 4 is formed as a flat surface, the rough screw 4 is ground compared to the case where the second machining teeth 32 are formed on the bottom of the rough screw 4. Processing becomes easy, and the processing cost can be reduced accordingly.

  Further, when the second working teeth 32 are formed by grinding, it is necessary to perform grinding with a tapered grindstone, so that the tip of the grindstone is easily chipped and the tool life of the grindstone is shortened. Then, since it is not necessary to form the second machining teeth 32 on the die material, there is an effect that it is possible to suppress an increase in machining cost due to grinding wheel damage.

  Moreover, since the 1st and 2nd process teeth 31 and 32 are formed by carrying out the plastic deformation of the valley bottom face of the rough screw 4, the to-be-processed surface of the 1st and 2nd process teeth 31 and 32 is an axial member. The pressed surfaces of the first and second processing teeth 31 and 32 are hardened by being pressed against the outer peripheral surface 50. Thereby, compared with the case where the 1st and 2nd process teeth 31 and 32 are formed by grinding, the intensity | strength of the 1st and 2nd process teeth 31 and 32 can be improved. The lifetime of the die 1 can be increased.

  Further, in the present invention, the roughing screw 4 is formed by grinding the die material, and the bottom surface of the rough screw 4 is plastically deformed by the shaft-like member 50, whereby the first and second processing teeth 31, 32 are formed. Form.

  Here, in the case where the first and second machining teeth 31 and 32 are formed by rolling without forming the rough screw 4 by grinding in advance, the amount of plastic deformation that plastically deforms the die material is the first machining tooth 31. It is about half the size of.

  On the other hand, in the present invention, as described above, the rough screw 4 is formed in advance by grinding, and the valley bottom surface of the rough screw 4 is plastically deformed by the shaft-like member 50. As a result, the plastic deformation amount for plastically deforming the die material is surrounded by the bottom surface of the rough screw 4 and a broken line below the bottom surface of the rough screw 4 (lower side in FIG. 3). It becomes volume.

  That is, the amount of plastic deformation of the die material can be reduced as compared with the case where the first and second machining teeth 31 and 32 are formed by rolling without forming the rough screw 4 by grinding. Therefore, the rolling process is facilitated, and the first and second processing teeth 31 and 32 can be formed with high efficiency.

  Furthermore, since the amount of plastic deformation of the die material can be reduced, the load applied to the double screw 51 of the shaft member 50 that bites into the die material can be reduced. As a result, the double screw 51 of the shaft-like member 50 can be prevented from being damaged, and the life of the shaft-like member 50 can be increased.

  Further, as described above, since the flank of the rough screw 4 is formed in a shape corresponding to the flank of the first processing tooth 31, the shaft-like member 50 is rolled on the die material on which the rough screw 4 is formed. When moving, the rough screw 4 engages with the coarse screw 52 of the shaft-shaped member 50, that is, the rough screw 4 plays a role of guiding the shaft-shaped member 50. As a result, the shaft-shaped member 50 can be rolled at an appropriate rotation pitch, and the shape of the second machining tooth 32 can be formed with high accuracy.

  The present invention has been described above based on the embodiments. However, the present invention is not limited to the above embodiments, and various improvements and modifications can be made without departing from the spirit of the present invention. It can be easily guessed.

  For example, in the above embodiment, the roughing screw 4 is formed by grinding the die material, and the first and second processing teeth 31 and 32 are formed by plastically deforming the bottom surface of the rough screw 4. However, the present invention is not necessarily limited to this, and the first and second processed teeth are produced by rolling the shaft-like member 50 on a flat die material on which the rough screw 4 is not formed, and plastically deforming the die material. 31 and 32 may be formed.

  Thereby, the 1st and 2nd process teeth 31 and 32 can be formed only by rolling the shaft-shaped member 50 on a die material, that is, the 1st and 2nd process teeth are simultaneously carried out by one rolling process. Since 31 and 32 can be manufactured, the step of forming the rough screw 4 can be omitted, and the rolling die 1 can be manufactured with high efficiency, and the rolling die 1 can be manufactured at a low cost. Can do.

  Moreover, in the said embodiment, although the rough screw 4 has the flank formed in the shape corresponding to the flank of the 1st process tooth 31, it is not necessarily restricted to this, The flank is the 1st process tooth. It may be configured to be larger than 31 flank, that is, the rough screw 4 may be configured to be larger than the first processing tooth 31.

  Moreover, each numerical value demonstrated by the said embodiment is an illustration, and it is naturally possible to employ | adopt another numerical value. Similarly, in the above-described embodiment, the case where the pitch of the second machining teeth 32 is half the pitch of the first machining teeth 31 has been described. However, the ratio (1/2) of both pitches is set to other ratios. (For example, 1/3, 2/3, etc.) is naturally possible.

  Moreover, although the said embodiment demonstrated the case where the lead and pitch of the 1st process tooth 31 were set larger than the lead and pitch of the 2nd process tooth 32, it is not necessarily restricted to this, 2nd Of course, it is possible to set the lead and pitch of the processing teeth 32 to be larger than the lead and pitch of the first processing teeth 31.

It is a figure explaining the rolling die in one embodiment of the present invention, (a) is a top view of a rolling die, and (b) is a side view of a rolling die. (A) is a front view of a shaft-shaped member, and (b) is a partially enlarged view of the shaft-shaped member. (A) to (d) is a partial sectional view of a tooth profile surface before rolling by a shaft-shaped member. (A) to (d) is a partial cross-sectional view of a rolled tooth profile surface from line IVa-IVa to line IVd-IVd in FIG. 1 (a), respectively.

DESCRIPTION OF SYMBOLS 1 Rolling die 2 Rolling tooth profile surface 4 Rough screw 31 1st processing tooth (coarse thread forming tooth profile)
32 Second processed tooth (tooth profile for fine thread formation)
50 Shaft-shaped member 51 Double screw 52 Coarse screw 53 Fine screw

Claims (1)

A rolled tooth surface having a coarse thread forming tooth form for forming a coarse thread and a fine thread forming tooth form for forming a fine screw is provided, and the material to be rolled is rolled on the rolled tooth surface. In a method for manufacturing a rolling die, which rolls a double screw in which coarse screws and fine screws having different leads coexist on the outer peripheral surface of the material to be rolled,
A rolling step of rolling on a die material a shaft-like member on which a double screw having coexisting coarse screws and fine screws coexisting on an outer peripheral surface is formed , and before the rolling step, the die material And a grinding process for grinding rough screws ,
Wherein the rolling step so bite into the outer peripheral surface of the shaft-like member to said die material, the said coarse thread forming teeth and the fine thread-forming teeth then rolling the die material,
The rough screw to be ground by the grinding step has a bottom surface of a valley formed on a flat surface, and a bottom surface of the valley formed on the flat surface has a substantially center of a flank that connects the top and bottom of the fine thread forming tooth profile. position and, and method of manufacturing a rolling die, wherein Rukoto is formed in a shape flanks corresponding to flanks of the coarse thread forming teeth on.

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