JP2008284566A - Apparatus for forging teeth having crowning - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for forging the teeth having crowning, which apparatus can form the teeth having the crowning with a stable working accuracy by a simple structure, and is excellent in its durability. <P>SOLUTION: The apparatus for forging the teeth having crowning includes a die holder 34 for supporting a die 37, and an inner punch 45 capable of axially moving toward the die 37. A drive ring 60 to be formed by laminating a base end layer ring member, an intermediate layer ring member, and a tip end layer ring member to be fitted on the outside of the die 37 are arranged on the die holder 34. An outer punch 43 is mounted on the outside of the inner punch 45 so as to axially move with respect to the die 37. The outer punch 43 makes both end portions of the die 37 in the axial direction elastically deform in the radial direction via the base end layer ring member and the tip end layer ring member. As a result, the crowning can be formed on the flanks of the respective teeth of a gear blank 10 with stable working accuracy. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a crowned forging molding apparatus for molding a crowning on a tooth surface of an external gear.

  Generally, the tooth surface of each tooth of the external gear has an end portion from the center in the tooth trace direction along the tooth trace so that the meshing of each tooth of the drive gear and the driven gear is good. The crowning is formed so that the tooth thickness gradually decreases toward the center. As a general method of crowning the tooth surface to form a crowned tooth profile, a rod material or forging material is roughly processed by gear cutting or the like to form a gear material with a constant tooth thickness, There is a method of crowning the tooth surface by cutting. However, a lot of processing time is required for crowning by cutting.

  In contrast, if the crowned tooth profile is formed by forging without cutting, the processing time can be greatly reduced. In order to forge a gear having a crowned tooth profile, a forging die having a die and a punch formed with a die hole having a curved concave surface corresponding to the tooth surface of the gear is used. Since the thickness of the central portion in the tooth trace direction is larger than both end portions, when the gear is taken out from the forging die by the ejector pin after gear forming, the thick portion will be ironed at the opening end of the die, A predetermined dimensional accuracy cannot be obtained.

  Therefore, for example, in Patent Document 1, before plastic processing the material set in the die hole, the opening end of the die is elastically contracted by a taper member, and then the material is plasticized into a toothed gear with crowning in the die hole. A processing method is disclosed in which when the processed and molded gear is taken out of the die, the elastic shrinkage on the opening end side of the die is released to widen the inner diameter on the opening end side. Each tooth is prevented from being ironed at the open end of the die.

  Patent Document 2 describes a molding apparatus that forges a material that has been previously processed to have a constant tooth thickness by rough machining into a toothed shape with crowning using two upper and lower dies. The lower die is provided with a plurality of first spaces having a portion where the lower end side is reduced, and the upper die is provided with a plurality of second spaces having a portion where the upper end side is reduced. To the first space to form a crowned tooth profile between the lower end and the center of each tooth of the material. Subsequently, after matching the first space of the lower die and the second space of the upper die, the teeth held in the first space by the lower punch are inserted into the second space from the upper end side to insert the teeth. A crowned tooth profile is formed between the upper end and the center. Thereby, the toothed gear with crowning is forged.

JP-A-7-51788 JP 2003-220442 A

  However, as described in Patent Document 1, when the opening end portion of the die hole of the die member is elastically contracted and deformed before the material is compressed by the punch and the die member, the die hole of the die member is In order to mold the crowning, it is necessary to process it into a complicated shape on the part opposite to the opening end. In addition, it is necessary to form the die member integrally with the container portion, and the structure of the die member is further complicated, which increases the manufacturing cost and maintenance cost of the forging apparatus.

  On the other hand, the molding apparatus described in Patent Document 2 requires two upper and lower dies and two upper and lower punches, which complicates the structure of the forging molding apparatus, and uses the upper punch to feed the material teeth into the first space of the lower die. A step of forming a crowning on the lower end side of the material by inserting it into the lower surface, a step of bringing the lower die and the upper die into close contact, and a tooth held in the first space by the lower punch from the upper end side in the second space And forming a crowning on the upper end side of the tooth, which complicates the forging process and increases the processing time.

  Therefore, in order to be able to forge the crowning on the tooth surface of each tooth with one die, the outer peripheral surface of the die is tapered, and a tapered sliding surface is formed on the punch that directly contacts the outer peripheral surface of the die. As a result, a forging apparatus has been developed in which both ends of the die in the axial direction are directly elastically contracted in the radial direction by punching. However, if the die is elastically deformed directly by punching, not only the sliding surface of the punch that comes into contact with the outer peripheral surface of the high hardness die will wear out in a short period of time, but also the outer peripheral surface of the die will wear out. The frequency of die change is increased, and it becomes difficult to ensure sufficient durability of the apparatus. In addition, when a tapered surface is formed on the outer peripheral surface of the die, it is necessary to change the die in order to change the amount of crowning.

  Accordingly, an object of the present invention made in view of such a point is to provide a crowned toothed forging device capable of forming a crowned toothed tooth having a stable processing accuracy with a simple structure.

  The invention for a forging device for crowning with tooth profile according to claim 1, which achieves the above object, is provided by crowning a tooth surface of a gear material having a plurality of teeth whose tooth thickness is uniformly formed throughout the tooth trace direction. A forging device with a crowning tooth shape for forming a die, wherein a plurality of tooth-forming grooves into which gear teeth are fitted are formed on the inner surface and supported by a die holder, and axially toward the die. An inner punch that is movably provided and presses the gear blank in the axial direction with the die holder, and is disposed on the die holder, each having a tapered outer peripheral surface and the inner peripheral surface being the outer peripheral surface of the die. The base layer ring-shaped member to be fitted, the inner peripheral surface is fitted with a gap in the outer peripheral surface of the die, and the intermediate layer ring-shaped member and the inner peripheral surface are fitted to the outer peripheral surface of the die. Advanced layer A driving ring in which ring-shaped members are sequentially stacked, and mounted on the outer side of the inner punch so as to be axially movable with respect to the die, the base layer ring-shaped member, the intermediate layer ring-shaped member, and the tip layer ring-shaped An outer punch that elastically contracts and deforms the member in the radial direction, and axially moves both ends in the axial direction of the die through the proximal layer ring member and the distal layer ring member by the axial movement of the outer punch. Then, it is elastically deformed in the circumferential direction, and crowning is formed on the tooth surface of each tooth of the gear material.

  According to the present invention, both ends of the die in the axial direction are diametrically arranged via the drive ring having a simple configuration in which the base layer ring-shaped member, the intermediate layer ring-shaped member, and the tip layer ring member are stacked by the axial movement of the outer punch. Since the elastic contraction deformation is performed in the direction and the circumferential direction, the crowned tooth profile can be formed by forming the crowning on the tooth surface of each tooth of the gear material by one step of bringing the outer punch close to the die. At this time, since the drive ring is configured by stacking the proximal layer ring member, the intermediate layer ring member, and the distal layer ring member, the proximal layer ring member, the intermediate layer ring member, and the distal layer ring member are each of the other layers. A driving force in the direction of diameter reduction is applied without being affected by the ring-shaped member, and the outer peripheral surfaces of both ends in the axial direction of the die are uniformly pressed by the inner peripheral surfaces of the base end layer ring-shaped member and the distal end layer ring-shaped member. The elastic shrinkage deformation in the radial direction and the circumferential direction is applied in contact with the surface, and a highly accurate crowning is formed on the tooth surface.

  In addition, when the outer peripheral surface of the base layer ring member, the intermediate layer ring member, or the tip layer ring member is worn by processing a large number of gear materials, only the worn ring member is replaced to change the other A gear blank can be formed using the ring-shaped member without replacement. Thus, since each ring-shaped member of the proximal layer ring-shaped member, the intermediate layer ring-shaped member, and the distal-end layer ring-shaped member is replaceable, the proximal-layer ring-shaped member whose outer peripheral surface has a different taper angle, By replacing the intermediate layer ring-shaped member and the tip layer ring-shaped member, the elastic shrinkage deformation amount in the radial direction of the die can be easily changed, or the crowning amount formed on the gear can be changed. In this case, expensive die changes can be omitted.

  According to a second aspect of the present invention, there is provided a crowned toothed forging apparatus according to the first aspect, wherein the taper-shaped contact member is in contact with the outer peripheral surfaces of the base layer ring-shaped member, the intermediate layer ring-shaped member, and the tip layer ring-shaped member. A processing block having a sliding surface and driven by the outer punch is disposed so as to be axially movable outside the base layer ring member, the intermediate layer ring member, and the tip layer ring member. To do.

  According to this invention, it has a processing block which has a taper-shaped sliding surface which contacts the outer peripheral surface of the base layer ring-shaped member, the intermediate layer ring-shaped member, and the tip layer ring-shaped member and is driven by the outer punch. Therefore, if the sliding surface is worn, it can be easily handled by replacing the machining block, and the maintenance can be simplified. Also, by replacing the processing block with a different taper angle of the sliding surface, it is possible to easily change the amount of elastic shrinkage deformation in the radial direction of the die, and change the amount of crowning formed on the gear. It can be easily done without changing.

  According to a third aspect of the present invention, there is provided the crowned toothed forging apparatus according to the second aspect, wherein the processing block is detachably mounted on the block main body, wherein the block main body and the tapered sliding surface are formed. And an annular portion.

  According to the present invention, the processing block is formed by the block main body and the annular portion attached to the block main body, and when the sliding surface is worn, only the annular portion is replaced without replacing the entire processing block. It can be handled and has excellent maintenance costs.

  According to a fourth aspect of the present invention, there is provided the crowned toothed forging apparatus according to any one of the first to third aspects, wherein the sleeve is fixed to the die holder and is in contact with the base end face side of the gear material, and It has a mandrel which moves in the axial direction together with the outer punch and widens the through hole formed in the gear material.

  According to the present invention, by providing the mandrel and the sleeve to which the mandrel is fitted, the gear material having the through hole can be processed, and the tooth surface crowning is performed while the gear material is radially expanded from the through hole side. Can be processed.

  According to a fifth aspect of the present invention, in the crowned toothed forging device according to any one of the first to fourth aspects, the proximal end layer ring-shaped member and the distal end layer ring-shaped member are each composed of a plurality of ring-shaped members. It is characterized by becoming.

  According to the present invention, it is possible to improve the machining accuracy by configuring a plurality of the proximal ring members and the distal ring members of the drive ring, and in particular, the tooth surface to be crowned has an axial dimension. Effective when large.

  According to the present invention, both ends of the die in the axial direction are moved through the drive ring having a simple configuration in which the base layer ring-shaped member, the intermediate layer ring-shaped member, and the tip layer ring member are stacked by the axial movement of the outer punch. Since the elastic contraction deformation is performed in the radial direction and the circumferential direction, the crowning can be formed on the tooth surface of each tooth of the gear material by one step in which the outer punch is brought close to the die, and the crowned tooth profile can be formed. The proximal end layer ring-shaped member, the intermediate layer ring member, and the distal end layer ring member are each applied with the driving force in the diameter reducing direction without being influenced by the other ring-shaped members, and the proximal end layer ring-shaped member and the distal end layer ring The inner peripheral surface of each member contacts the outer peripheral surfaces of both ends of the die in the axial direction with uniform pressing force, and elastic shrinkage deformation in the radial direction and the circumferential direction is imparted to the tooth surface with high accuracy. Uningu is molded.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a crowned toothed forging apparatus according to the present invention will be described below with reference to FIGS.

  FIG. 1A is a perspective view showing an example of a gear material, and FIG. 1B is a perspective view showing the gear after forging a crowning on a tooth surface of the gear material to produce a product. FIG. 2 is a cross-sectional view showing a crowned toothed forging apparatus according to the present embodiment, FIG. 3 is an enlarged cross-sectional view of part A in FIG. 2, and FIG. 4 is an enlarged view of part B in FIG.

  A gear material 10 shown in FIG. 1A is formed by cutting or forging a bar material. The gear material 10 includes a boss portion 11 and a gear main body portion 12 integrally formed with the boss portion 11. And a through-hole 13 is formed in the central portion. In the gear body 12, a plurality of teeth 14 and tooth grooves 15 between adjacent teeth 14 are formed at equal pitches in the circumferential direction. Each of the teeth 14 and the tooth gap 15 extends in the axial direction, the tooth thickness of each tooth 14 is constant over the entire tooth trace direction, and the intersecting line between the tooth surface 16 and the tooth tip surface 17 is linear. Therefore, the tooth surface 16 is flat. When the tooth surface 16 of the gear material 10 is crowned by the forging apparatus 20, the gear surface 10 is processed into the gear 10 a shown in FIG. 1 (b), and the tooth surface 16 becomes thicker as it moves from the center to the both ends in the tooth trace direction. Is formed into a product so as to gradually decrease.

  The forging apparatus 20 shown in FIG. 2 includes a lower mold 21 and an upper mold 22 that is movable in the vertical direction toward the lower mold 21. The lower mold 21 has a bolster 24 fixed to a base 23, and the bolster 24 includes a base cylinder 24a and a support cylinder 24b fixed to the upper part thereof. A cylindrical vertical movement block 25 is mounted in the support cylinder 24b so as to be movable in the vertical direction. A processing block 27 is mounted on the vertical movement block 25 via a spacer 26. A plurality of pressing pins 28 are attached to the bolster 24, and thrust is applied to the pressing pins 28 by a spring member or hydraulic pressure (not shown), and the processing block 27 is moved up and down by the pressing pins 28. Further, an upward thrust toward the upper mold 22 is applied via the spacer 26. An annular fixing ring 29 that comes into contact with the machining block 27 is attached to the support cylinder 24b, and the upward movement of the machining block 27 is restricted. A guide post 30 for guiding the movement of the upper mold 22 when the upper mold 22 is moved toward the lower mold 21 is provided on the lower mold 21 and is slidably fitted to the guide post 30. A guide member not to be mounted is attached to the upper mold 22.

  As shown in FIG. 2, a cylindrical support 31 is incorporated in the center of the support cylinder 24b of the bolster 24, and this support 31 is mounted on a pedestal 32 fixed to the base cylinder 24a. It is fixed through. An annular die holder 34 is disposed on the support base 31, and a sleeve 35 is incorporated in the center of the support base 31. The sleeve 35 is fixed to the base 32 via a hollow spacer 36.

  As shown in FIGS. 3 and 4, a cylindrical die 37 having a through hole 37 a into which the gear material 10 is fitted is supported by the die holder 34, and the base end surface, that is, the lower end surface of the die 37 is the die holder 34. And is supported by the die holder 34.

  FIG. 5 is a partially broken perspective view showing the die 37 and the drive ring 60 in an enlarged manner. A plurality of tooth-forming grooves 38 are formed on the inner surface of the through hole 37a of the die 37 in the axial direction. Each tooth forming groove 38 has a tooth surface forming surface 38a corresponding to the tooth surface 16 of the gear blank 10 and a tooth tip forming surface 38b corresponding to the tooth tip surface 17, and the tooth surface forming surface 38a is a gear material. It is formed flat corresponding to ten tooth surfaces 16. Further, the outer peripheral surface 39 of the die 37 is formed with a large-diameter outer peripheral surface 39a on the base end side and a small-diameter outer peripheral surface 39b on the distal end side, and has a stepped shape. The surface 39b is a straight cylindrical surface parallel to the central axis.

  On the other hand, as shown in FIG. 2, the upper die 22 has a main ram 41 that can move toward and away from the lower die 21 in the axial direction, and the main ram 41 has a cylindrical shape by a cylindrical holder 42. An outer punch 43 is attached, and the outer punch 43 is fixed to the holder 42 by a nut member 44 that is screwed to the holder 42. A substantially cylindrical inner punch 45 is incorporated in the central portion of the outer punch 43 so as to be movable in the axial direction with respect to the outer punch 43. A plurality of interlocking rods 47 are arranged between them. The inner punch 45 moves close to and away from the lower die 21 together with the outer punch 43 by the main ram 41, and further the inner punch 45 can move relative to the outer punch 43 in the axial direction by the inner ram 46.

  A mandrel 51 is attached to the lower surface of the support block 48 fixed in the holder 42 by a fixed block 49 so as to be positioned at the center of the outer punch 43. The mandrel 51 is coaxial with the sleeve 35. When the upper die 22 moves closer to the lower die 21, the mandrel 51 is fitted into the sleeve 35 as shown in FIG. At the tip of the mandrel 51, a small diameter portion 52b smaller than the main body portion 52a is provided. The gear blank 10 is plastically processed so that the through-hole 13 is pushed and expanded by the large-diameter main body 52a on the base end side after entering the inside 13.

  As shown in FIG. 2 and FIG. 3, a first ring-shaped member 61 and a second ring-shaped member 62 that are base end layer ring-shaped members fitted to the outside of the die 37, and a third ring-shaped member that is an intermediate layer ring-shaped member. A drive ring 60 in which a ring-shaped member 63, a fourth ring-shaped member 64 serving as a tip-layer ring-shaped member, and a fifth ring-shaped member 65 are stacked is detachably disposed on the die holder 34.

  The processing block 27 that is mounted on the support cylinder 24b so as to be movable in the vertical direction is formed by a block main body 27a and an annular portion 27b that is detachably attached to the central portion of the block main body 27a. As shown in FIGS. 3 and 4, the inner peripheral surface is a tapered sliding surface 27 c.

  As shown in FIGS. 4 and 5, the first ring-shaped member 61 constituting the drive ring 60 is an annular shape having a proximal end surface 61 a and a distal end surface 61 b that are in contact with the die holder 34, and an inner peripheral surface 61 c is a large die 37. The outer peripheral surface 61d is formed in a tapered shape that comes into contact with the sliding surface 27c of the annular portion 27b as the outer peripheral surface 61d moves toward the base end surface 61a.

  The second ring-shaped member 62 has an annular shape having a proximal end surface 62 a that contacts the distal end surface 61 b of the first ring-shaped member 61 and a distal end surface 62 b, and the inner peripheral surface 62 c contacts the large-diameter outer peripheral surface 39 a of the die 37. The outer peripheral surface 62d is formed into a tapered shape having a larger diameter as it moves toward the base end surface 62a, and contacts the sliding surface 27c of the annular portion 27b.

  The third ring-shaped member 63 is an annular shape having a base end surface 63 a that contacts the distal end surface 62 b of the second ring-shaped member 62 and a distal end surface 63 b, and the inner peripheral surface 63 c does not contact the outer peripheral surface 39 of the die 37. The outer peripheral surface 63d has a sufficient interval, is formed in a tapered shape having a larger diameter as it moves toward the base end surface 63a, and contacts the sliding surface 27c of the annular portion 27b.

  The fourth ring-shaped member 64 is an annular shape having a base end surface 64a and a front end surface 64b that are in contact with the front end surface 63b of the third ring-shaped member 63, and the inner peripheral surface 64c is in contact with the small-diameter outer peripheral surface 39b of the die 37. The outer peripheral surface 64d is formed in a tapered shape having a larger diameter as it moves toward the base end surface 64a, and comes into contact with the sliding surface 27c of the annular portion 27b.

  The fifth ring-shaped member 65 is an annular shape having a base end surface 65 a that contacts the distal end surface 64 b of the fourth ring-shaped member 64 and a distal end surface 65 b, and the inner peripheral surface 65 c is in contact with the small-diameter outer peripheral surface 39 b of the die 37. The outer peripheral surface 65d is formed in a tapered shape having a larger diameter as it moves toward the base end surface 65a, and comes into contact with the sliding surface 27c of the annular portion 27b.

  Thereby, as shown in FIGS. 2 and 3, when the upper die 22 further moves downward from the state in which the outer punch 43 is in contact with the processing block 27 supported in the axial direction by the support cylinder 24b, The processing block 27 is driven together with the spacer 26 and the vertical movement block 25 by the outer punch 43 further downward than the position shown in FIGS. 2 and 3, and the first ring member 61 and the second ring shape of the drive ring 60 are driven. The member 62, the third ring-shaped member 63, the fourth ring-shaped member 64, and the fifth ring-shaped member 65 receive a driving force contracting in the radial direction by the sliding surface 27c of the processing block 27.

  When the first ring-shaped member 61, the second ring-shaped member 62, the third ring-shaped member 63, the fourth ring-shaped member 64, and the fifth ring-shaped member 65 of the drive ring 60 receive a driving force from the processing block 27, A large-diameter outer peripheral surface 39a on the base end side of 37 is in contact with the inner peripheral surface 61c of the first ring-shaped member 61 and the inner peripheral surface 62c of the second ring-shaped member 62, which are base end layer ring-shaped members, and the die 37. The small-diameter outer peripheral surface 39b on the distal end side of the first member contacts the inner peripheral surface 64c of the fourth ring-shaped member 64 and the inner peripheral surface 65c of the fifth ring-shaped member 65, which are front-end layer ring-shaped members. Since the central portion is not in contact with the inner peripheral surface 63c of the third ring-shaped member 63 which is an intermediate layer ring-shaped member, the die 37 has the first ring-shaped member 61, the second ring-shaped member 62, and the fourth ring-shaped member. Member 64, fifth Pressed against the both end portions, i.e. the base end and a distal end side radially inward by ring-shaped member 65, both end portions of the die 37 will be elastically contracted and deformed in the radial and circumferential directions. Since both ends of the die 37 have the largest amount of elastic contraction deformation in the radial direction and the circumferential direction, the tooth surface 16 of the gear blank 10 has teeth along the tooth traces as shown in FIG. A crowning that is curved so as to gradually decrease the wall thickness, that is, the tooth thickness, is processed from the central portion toward the end in the muscle direction.

  In this way, the upper die 22 is brought close to the lower die 21, and the first ring-shaped member 61, the second ring-shaped member 62, the fourth ring-shaped member 64, and the fifth ring-shaped member 65 of the drive ring 60 by the outer punch 43. The die 37 is elastically shrunk and deformed in the radial direction and the circumferential direction through the crown to perform the crowning process. When the upper die 22 moves closer to the lower die 21, the small-diameter portion 52b at the tip of the mandrel 51 is first moved. The gear material 10 enters the through-hole 13 of the gear material 10, and is continuously expanded by the large-diameter main body 52 a of the mandrel 51, and crowned by the die 37.

  Here, the drive ring 60 for performing the crowning process is separated into a first ring-shaped member 61, a second ring-shaped member 62, a third ring-shaped member 63, a fourth ring-shaped member 64, and a fifth ring-shaped member 65. As a result, the outer peripheral surfaces 61d, 62d, 64d, 65d of the first ring-shaped member 61, the second ring-shaped member 62, the fourth ring member 64, and the fifth ring-shaped member 65 are the other ring-shaped members. The first ring-shaped member 61, the second ring-shaped member 62, the fourth ring-shaped member 64, and the first ring-shaped member 61, the second ring-shaped member 62, and the fourth ring-shaped member 64. A driving force in the diameter reducing direction is applied to the fifth ring-shaped member 65. As a result, the large-diameter outer peripheral surface 39a of the die 37 reliably contacts the inner peripheral surfaces 61c and 62c of the first ring-shaped member 61 and the second ring-shaped member 62, and the small-diameter outer peripheral surface 39b on the tip end side of the die 37 is the first. The four ring-shaped member 64 and the fifth ring-shaped member 65 are reliably brought into contact with the inner peripheral surfaces 64c and 65c, and both ends of the die 37 are given elastic contraction deformation in the radial direction and the circumferential direction. A highly accurate crowning that is curved so that the wall thickness, that is, the tooth thickness, gradually decreases from the center to the end in the tooth trace direction is processed on the tooth surface 16.

  On the other hand, if the drive ring 60 for performing the crowning process is integrally formed without being separated into each ring-shaped member, the outer peripheral surface of the drive ring is caused by the processing accuracy of the sliding surface of the drive ring and the processing block, wear due to use, or the like. There is a concern that the sliding surface of the processing block may contact locally. When the outer peripheral surface of the drive ring and the sliding surface of the machining block come into local contact, the driving force in the reduced diameter direction that is unevenly distributed on the drive ring is applied and the inner peripheral surface of the drive ring deforms locally so that the die 37 There is a concern that stable elastic processing of the crowning formed on the tooth surface 16 of the gear blank 10 cannot be secured due to uneven elastic contraction deformation at both ends.

  Further, the drive ring 60 in the present embodiment is separated into a first ring member 61, a second ring member 62, a third ring member 63, a fourth ring member 64, and a fifth ring member 65. By laminating, the outer peripheral surfaces 61d, 62d, 64d, 65d of the first ring-shaped member 61, the second ring-shaped member 62, the fourth ring member 64, and the fifth ring-shaped member 65 become the other ring-shaped members, respectively. The first ring-shaped member 61, the second ring-shaped member 62, the third ring-shaped member 63, the fourth ring-shaped member 64, and the like reliably contact the sliding surface 27 c of the processing block 27 without being affected. Compared to the case where the fifth ring member 65 is integrally formed, the first ring member 61, the second ring member 62, the third ring member 63, the fourth ring member 64, and the fifth ring member 65 are integrated. Perimeter 61d, 62d, 63d, 64d, manufacturing cost of the required machining accuracy relaxed driving ring 60 of the taper angle of 65d is reduced.

  FIG. 6 is a cross-sectional view showing a state in which the upper die 22 is closest to the lower die 21, and shows a state in which the crowning process is completed. 7 is a cross-sectional view showing a state where the upper die 22 is separated from the lower die 21 after the crowning process is completed, and FIGS. 6 and 7 are parts of the forging apparatus 20 shown in FIG. Indicates.

  Next, a processing procedure for processing the gear blank 10 shown in FIG. 1A by the forging apparatus shown in FIG. 2 and crowning the tooth surface 16 to form a crowned tooth profile will be described.

  The gear blank 10 is set in the through hole 37 a of the die 37 with the upper die 22 retracted upward from the lower die 21. At this time, the processing block 27 is held at the ascending limit position in contact with the fixing ring 29. On the other hand, the gear blank 10 is in a state in which each tooth 14 is fitted in the tooth forming groove 38 of the die 37, and the boss portion 11 is on the upper side and the base end side of the tooth 14 is shown in FIG. These end surfaces are placed on the sleeve 35 and are held in the die 37.

  When the upper mold 22 is moved toward the lower mold 21 in the state where the gear material 10 is set, that is, when the upper material 22 is moved downward, the small diameter portion 52b formed at the tip of the mandrel 51 is first moved to the gear material 10. The outer punch 43 is processed into the processing block 27 while the gear material 10 is plastically processed so that the large-diameter main body portion 52a is inserted into the through-hole 13 and spreads the through-hole 13 after being inserted into the through-hole 13. And the inner punch 45 comes into contact with the end surface of the gear blank 10 on the tip end side. 2 and 3 show a state in which the outer punch 43 is in contact with the machining block 27 and the inner punch 45 is in contact with the gear material 10.

  The taper-shaped sliding surface 27c formed in the annular portion 27b of the processing block 27 pushed down by the outer punch 43 by the downward movement of the upper die 22 is the first ring-shaped member 61 and the second ring-shaped member of the drive ring 60. 62, the third ring-shaped member 63, the fourth ring-shaped member 64, and the fifth ring-shaped member 65 are in sliding contact with the outer peripheral surfaces 61d, 62d, 63d, 64d, 65d formed in the tapered shape, and the sliding surface The small-diameter side of 27c moves toward the large-diameter side of each outer peripheral surface 61d, 62d, 63d, 64d, 65d, and the first ring-shaped member 61, the second ring-shaped member 62, the third ring-shaped member 63, The fourth ring member 64 and the fifth ring member 65 are deformed so as to contract in the radial direction.

  The large-diameter outer peripheral surface 39a on the base end side of the die 37 is in contact with the inner peripheral surface 61c of the first ring-shaped member 61 and the inner peripheral surface 62c of the second ring-shaped member 62, which are base end layer ring-shaped members, The small-diameter outer peripheral surface 39b on the tip end side of the die 37 is in contact with the inner peripheral surface 64c of the fourth ring-shaped member 64 and the inner peripheral surface 65c of the fifth ring-shaped member 65, which are the tip layer ring-shaped members. The central portion in the direction is not in contact with the inner peripheral surface 63c of the third ring-shaped member 63 that is an intermediate layer ring-shaped member. As a result, the dice 37 are formed so that both ends, that is, the proximal end side and the distal end side are radially inward by the first ring-shaped member 61, the second ring-shaped member 62, the fourth ring-shaped member 64, and the fifth ring-shaped member 65. The both ends of the die 37 are pressed and elastically deformed in the radial direction and the circumferential direction. Since both ends of the die 37 have the largest amount of elastic contraction deformation in the radial direction and the circumferential direction, the tooth surface 16 of the gear blank 10 has teeth along the tooth traces as shown in FIG. A crowning that is curved so as to gradually decrease the wall thickness, that is, the tooth thickness, is processed from the central portion toward the end in the muscle direction.

  As shown in FIG. 6, when the upper mold 22 moves down to the position closest to the lower mold 21, the crowning process is completed and the process of expanding the through hole 13 by the mandrel 51 is completed.

  When the upper die 22 is lifted and moved away from the lower die 21 from the crowned state shown in FIG. 6, the machining block 27 is brought into contact with the fixing ring 29 by the upward movement of the outer punch 43 as shown in FIG. The inner punch 45 is separated from the gear material 10 and the mandrel 51 is separated from the through hole 13 of the gear material 10. In this state, the gear 10 a that is a product obtained by processing the crowning of the gear material 10 is removed from the lower mold 21.

  In order to perform the same processing on another gear material 10, the gear material 10 is set in a die 37 of the lower die 21 with the upper die 22 separated from the lower die 21, as shown in FIG. 7. The crowning is processed on the tooth surface 16 of the gear blank 10 by the procedure described above.

  In the forging apparatus of the present invention, the first ring-shaped member 61, the second ring-shaped member 62, the third ring-shaped member 63, the fourth ring-shaped member 64, and the fifth that constitute the drive ring 60 outside the die 37. Since the ring-shaped member 65 is fitted, and the processing block 27 is formed with the sliding surface 27c in sliding contact with the tapered outer peripheral surfaces 61d, 62d, 63d, 64d, 65d of each ring-shaped member, a large number of gear materials When the outer peripheral surface of the ring-shaped member is worn by machining 10, the second ring-shaped member 62, the third ring-shaped member 62, and the third ring-shaped member 62 are replaced by replacing only the worn ring-shaped member, for example, the first ring-shaped member 61. The gear material 10 can be processed without replacing the ring-shaped member 63, the fourth ring-shaped member 64, and the fifth ring-shaped member 65.

  Further, when the outer peripheral surface of the ring-shaped member constituting the drive ring 60 is worn by processing a large number of gear materials 10, the first ring-shaped member 61, the second ring-shaped member 62, the third ring-shaped member The gear blank 10 can be processed using the expensive die 37 as it is without exchanging the die 37 by exchanging the 63, the fourth ring-shaped member 64, and the fifth ring-shaped member 65.

  Similarly, the processing block 27 is formed by a block main body 27a and an annular portion 27b attached to the block main body 27a. When the sliding surface 27c formed on the annular portion 27b is worn, only the annular portion 27b is replaced. can do.

  Thus, the first ring-shaped member 61, the second ring-shaped member 62, the third ring-shaped member 63, the fourth ring-shaped member 64, the fifth ring-shaped member 65, and the processing block 27 that constitute the drive ring 60. Since the annular portion 27b is exchangeable, the first ring-shaped member 61, the second ring-shaped member 62, the third ring-shaped member 63, the fourth ring-shaped member 64, the outer peripheral surface 61d of the fifth ring-shaped member 65, 62d, 63d, 64d, 65d and the taper angle of the sliding surface 27c of the annular portion 27b are changed to change the amount of elastic contraction deformation in the radial direction of the die 37 with respect to the movement stroke of the upper die 22, or to the gear 10a. Changing the amount of crowning formed can be easily performed without changing the die 37.

  In the forging apparatus shown in the drawing, the processing block 27 is constituted by a block main body 27a and an annular portion 27b which is detachably attached to the block main body 27a. However, the annular portion 27b and the block main body 27a may be integrated. good. The machining block 27 is mounted on the support cylinder 24b of the lower die 21 so as to be movable up and down. The machining block 27 is moved in the axial direction by the axial movement of the outer punch 43, and the axial movement of the machining block 27 is performed via a tapered surface. The first ring-shaped member 61, the second ring-shaped member 62, the third ring-shaped member 63, the fourth ring-shaped member 64, and the fifth ring-shaped member 65 are converted into elastic contraction deformation in the radial direction and the circumferential direction. However, the outer peripheral surfaces 61d, 62d, 63d, 64d, 65d of the first ring-shaped member 61, the second ring-shaped member 62, the third ring-shaped member 63, the fourth ring-shaped member 64, and the fifth ring-shaped member 65 are shown. By providing the outer punch 43 with a sliding surface 27c that makes sliding contact with the outer punch 43, the outer ring 43 directly causes the first ring-shaped member 61, the second ring-shaped member 62, the third ring-shaped member 63, and the fourth ring-shaped member. Grayed-like member 64 may be a fifth ring-shaped member 65 in the radial direction so as to elastically contracted and deformed.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the first ring-shaped member 61, the second ring-shaped member 62, the third ring-shaped member 63, the fourth ring-shaped member 64, and the inner peripheral surfaces 61 c, 62 c, 63 c of the drive ring 60, The sliding surface 27c formed by the inner peripheral surface of 64c, 65c or the annular portion 27b is formed into a polygonal shape without having a circular cross section, so that a specific portion in the circumferential direction of the gear material 10 is locally formed. Anyway.

  In the above-described embodiment, the first ring-shaped member 61 and the second ring-shaped member 62 are provided as the base end layer ring-shaped member of the drive ring 60, and the fourth ring is used as the tip layer ring-shaped member. Although the two ring-shaped members of the ring-shaped member 64 and the fifth ring-shaped member 65 are provided, it is possible to simplify the structure by reducing the number of components by configuring each of the ring-shaped members with one ring-shaped member. it can. Further, by forming the base end layer ring-shaped member and the tip end layer ring member of the drive ring 60 by three or more, it is possible to improve the processing accuracy. This is particularly effective when the tooth surface to be crowned is long in the axial direction. Also, a plurality of intermediate layer ring-shaped members can be stacked and mounted.

  As shown in FIG. 1 (a), the forging apparatus is applied to process a gear material 10 having a through hole 13 formed in the center, but a gear material not provided with a through hole 13 is used. Forging may be performed. In that case, the sleeve 35 is not provided on the lower die 21, and the mandrel 51 is not provided on the upper die 22. 1 is applied to crown the tooth surface 16 of the spur gear shown in FIG. 1, the crowning process is also performed on the tooth surface of the helical gear by replacing the die 37. be able to.

(A) is a perspective view which shows an example of a gear raw material, (b) is a perspective view which shows the gear after forging a crowning to the tooth surface of the gear raw material and commercializing it. It is sectional drawing which shows the forging shaping | molding apparatus of the tooth profile with a crowning which is one embodiment of this invention which processes crowning on the tooth surface of a gear raw material. It is the A section expanded sectional view of FIG. FIG. 4 is an enlarged cross-sectional view of a B part in FIG. 3. It is a partially broken perspective view which expands and shows a die and a drive ring. It is sectional drawing which shows the part same as FIG. 3 in the state which the upper mold | type approached the lower mold | type most, and the process was complete | finished. It is sectional drawing which shows the part same as FIG. 3 in the state which separated the upper mold | type from the lower mold | type after crowning process was completed.

Explanation of symbols

10 Gear material 10a Gear 14 Tooth 15 Tooth groove 16 Tooth surface 20 Forging device 21 Lower die 22 Upper die 27 Processing block 27a Block body 27b Annular portion 27c Sliding surface 34 Die holder 35 Sleeve 37 Die 37a Through hole 38 Tooth forming groove 39 Outer peripheral surface 39a Large diameter outer peripheral surface 39b Small diameter outer peripheral surface 43 Outer punch 45 Inner punch 51 Mandrel 60 Drive ring 61 First ring-shaped member (base end layer ring-shaped member)
61c Inner peripheral surface 61d Outer peripheral surface 62 Second ring-shaped member (base end layer ring-shaped member)
62c Inner peripheral surface 62d Outer peripheral surface 63 Third ring member (intermediate layer ring member)
63c Inner peripheral surface 63d Outer peripheral surface 64 Fourth ring-shaped member (tip layer ring-shaped member)
64c Inner peripheral surface 64d Outer peripheral surface 65 Fifth ring-shaped member (tip layer ring-shaped member)
65c inner peripheral surface 65d outer peripheral surface

Claims (5)

A toothed forging device with a crowning that forms a crowning on a tooth surface of a gear material having a plurality of teeth whose tooth thickness is formed uniformly throughout the tooth trace direction,
A plurality of teeth forming grooves into which the teeth of the gear material are fitted are formed on the inner surface and supported by a die holder;
An inner punch that is provided so as to be movable in the axial direction toward the die and presses the gear material in the axial direction with the die holder;
A base layer ring-shaped member disposed on the die holder, each having a tapered outer peripheral surface and the inner peripheral surface being fitted to the outer peripheral surface of the die, and the inner peripheral surface having a gap on the outer peripheral surface of the die. A drive ring in which an intermediate layer ring-shaped member to be fitted and a tip layer ring-shaped member whose inner peripheral surface is fitted to the outer peripheral surface of the die are sequentially stacked;
An outer punch that is mounted on the outside of the inner punch so as to be axially movable with respect to the die, and elastically deforms the proximal layer ring member, the intermediate layer ring member, and the distal layer ring member in a radial direction. Have
By axial movement of the outer punch, both axial end portions of the die are elastically contracted and deformed in the radial direction and circumferential direction via the proximal end layer ring-shaped member and the distal end layer ring-shaped member, and each tooth of the gear material is deformed. A forging device for crowning with tooth profile, characterized by molding crowning on the tooth surface.   A processing block that has a tapered sliding surface that comes into contact with the outer peripheral surfaces of the base layer ring-shaped member, the intermediate layer ring-shaped member, and the tip layer ring-shaped member and that is driven by the outer punch is formed as the base layer ring. 2. The forging apparatus for crowned tooth profile according to claim 1, wherein the forging apparatus is configured to be axially movable outside the ring-shaped member, the intermediate layer ring-shaped member, and the tip layer ring member. The above processing block is
A block body;
3. The crowned tooth profile forging device according to claim 2, further comprising an annular portion formed with the tapered sliding surface and detachably attached to the block main body. A sleeve fixed to the die holder and in contact with the base end face side of the gear material;
The forging of the crowned tooth profile according to any one of claims 1 to 3, further comprising a mandrel that moves in the axial direction together with the outer punch and expands a through hole formed in the gear material. apparatus.   5. The crowned toothed forging device according to claim 1, wherein each of the base layer ring-shaped member and the tip layer ring-shaped member includes a plurality of ring-shaped members.

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