JPH0263632A - Ironing method for tooth form of gear - Google Patents

Abstract

PURPOSE:To improve the forming accuracy of a gear by providing a finish tooth die of first and second lands having a larger dimension than a forming target value and a target value dimension on a die and ironing continuously an intermediate forming stock in the die. CONSTITUTION:The upper die 7 is provided against the lower die 6 consisting of dies 4, 5, and on the inside surface of the upper part of the outer lower die 5, a finish tooth die 20 is provided. In the tooth die 20, the lower end containing recessed part 71 of the upper die 7, the first land 72 whose dimension is larger than a forming target value, and the second land 73 of a target dimension are formed, respectively. In this state, an intermediate forming stock 1 is placed on the lower die 6, and by allowing the upper die set plate 42 to descend, a rough formed part 2 of the stock 1 is formed continuously by the lands 72, 73. In this case, the dies 4, 5 turn synchronously and ironing is executed smoothly. In such a way, the forming accuracy of a gear is improved irrespective of a variance of the stock 1.

Description

Detailed Description of the Invention A0 Object of the Invention (1) Industrial Application Field The present invention is directed to rough forming the rough tooth profile portion of a helical gear such as a helical gear in which the tooth trace is non-linear on the outer periphery. The intermediate molded material made by
The present invention relates to a method for ironing the teeth of a gear by pressing it into a die having a finishing tooth shape and ironing the gear.

(2) Conventional technology Conventionally, as a method for ironing the teeth of such a gear, an intermediate forming material is pushed into a die having a finishing tooth shape and transferred, similar to the technique disclosed in JP-A No. 62-110831, for example. There are known methods of molding, and methods of pushing and squeezing an intermediate molding material that is the same size or slightly larger than the finished tooth mold into a die that has a finishing tooth mold that has a molding land at the entrance.

(3) Problems to be Solved by the Invention However, in the conventional method described above, the molding accuracy is greatly influenced by the dimensions of the intermediate molding material. In other words, if there are variations in the dimensions of the intermediate forming material due to wear of the mold used to form the intermediate forming material or the influence of the slope of the punching process, differences will occur in the pressing force of each part of the material during ironing, and the material will not be released from the die after the forming process. When this happens, the dimensions of each part appear as variations in the amount of springback. Therefore, even if a force exceeding a predetermined pressing force is applied with the aim of achieving a straightening effect using forging force, the finished tooth surface cannot withstand the surface pressure, resulting in seizure and galling phenomena.To avoid this, it is necessary to It is necessary to apply bonderite treatment to the surface in advance.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for ironing the teeth of a gear, which allows ironing to be performed smoothly and accurately regardless of dimensional variations in the intermediate forming material. do.

B0 Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention provides a rough tooth profile of a helical gear, such as a helical gear, in which the tooth trace is non-linear, by In a gear tooth shape ironing forming method in which an intermediate forming material formed by rough forming is pressed into a die having a finishing tooth shape and ironing is performed, a first land having dimensions larger than a forming target value and a forming target value are used. the first with dimensions corresponding to
A finishing tooth pattern with a second land connected to the land is provided on the die, and the intermediate forming material is pushed into the die while applying counter pressure, and the coarse tooth profile part is ironed with the ironing allowance of a certain value or more by the first land. It is characterized in that the coarse tooth profile portion is squeezed by the second land continuously.

(2) Effect According to the above method, since the first land has a dimension larger than the forming target value, the intermediate forming material can be squeezed with an ironing amount of a certain value or more regardless of the dimensional variation of the intermediate forming material, Furthermore, by squeezing the second land that is continuous with the first land, it is possible to improve the molding accuracy and to make the squeezing action smoother.

(3) Example Hereinafter, an example of the present invention will be explained with reference to the drawings. First, in the first step, the intermediate forming material 1 that has been forged in a heated state is repeatedly formed by the forming device 3, thereby forming tooth traces. For example, a helical gear having non-linear teeth on its outer periphery is molded. This intermediate forming material 1 has a non-linear tooth trace, for example, a helical rough tooth profile part 2 on the outer periphery, and at one end of the rough tooth profile part 2, a burr part 2a generated during forging is left over the entire circumference. It's still there.

The forming device 3 includes a lower die 6 consisting of an inner lower die 4 and an outer lower die 5, an upper die for sandwiching the intermediate forming material 1 between the inner lower die 4 and pushing it into the outer lower die 5, and a lower die for lowering the upper die. A rotary drive mechanism 8 for synchronously rotating the outer lower die 5; and a rotary drive mechanism 8 for synchronously operating the rotary drive mechanism 8 when the upper die is lowered in accordance with the axial dimension variation of the intermediate forming material 1. A synchronization interlocking mechanism 9 is provided.

A lower die set plate 11 is fixed on the fixed lower die set plate 10, and a base plate 1 is fixed on the lower die plate 1.
A cylindrical lower die holder 13 is fixed via 2. This lower die holder 3 basically consists of an upper holder part 14, a middle holder part 15, and a lower holder part 16, each formed in a cylindrical shape, which are coaxially stacked and fixed to each other. A basically cylindrical outer lower die 5 is supported by the lower die holder 3 via sliding metals 17, 18, and 19 so as to be rotatable around a vertical axis. Further, on the inner surface of the outer lower die 5 near the upper part, a finishing tooth die 20 formed in a helical tooth shape is provided for ironing the rough tooth profile portion 2 .

The inner lower die 4 is basically formed in a cylindrical shape, and is disposed coaxially within the outer lower die 5 so as to be able to move up and down. A metal 22 is interposed. Moreover, the upper outer surface of the inner lower die 4 has a tooth portion 21 that meshes with the finishing tooth pattern 20 of the outer lower die 5.
is provided. Further, the upper end surface of the inner lower die 4 is formed in a shape corresponding to the lower surface of the intermediate molding material 1 on which the intermediate molding material 1 is placed.

A support plate 2 is provided at the lower center of the lower holder portion 16 of the lower die holder 13 to enable vertical movement within a limited range.
3 is arranged, and the lower end of the inner lower die 4 is supported on this support plate 23 via a thrust bearing member 24. Therefore, the inner lower die 4 is rotatable about the vertical axis on the support plate 23. In addition, cylinders 25 are arranged at a plurality of positions in the circumferential direction on the lower goo plate 11 with their axes in the vertical direction, and these cylinders 2
The piston rod 25a of No. 5 passes through the base plate 12 and comes into contact with the lower surface of the support plate 23.

A lower bunch 26 is disposed within the inner lower die 4 so as to be movable up and down, and a spring 27 is contracted between the lower punch 26 and the inner lower die 4 to bias the lower punch 26 downward. Ru. Moreover, the lower limit position of the lower punch 26 relative to the inner lower die 4 is regulated by the lower end of the lower punch 26 coming into contact with the upper surface of the support plate 23, and the upper end of the lower punch 26 is placed on the lower die 6 at the lower limit position. This is a position where it can come into contact with the lower surface of the intermediate molding material 1.

The lower part of the knockout pin 28, which passes through the center of the lower guide set plate 10, lower guide plate 11, and base plate 12 in a vertically movable manner, is connected to a driving means such as a cylinder (not shown), and the upper end of the knockout pin 28 is connected to a driving means such as a cylinder (not shown). It can come into contact with the center of the lower end surface of the lower bunch 26 through a through hole 29 provided in the center of the support plate 23 .

In FIG. 2, the rotation drive mechanism 8 includes a screw shaft 3 that is movable up and down and supported by a lower guide holder 13.
1, a drive gear 32 screwed onto the screw shaft 31, a driven gear 33 provided on the outer lower die 5 to mesh with the drive gear 32, and interlocked with the upper die to press the screw shaft 31 downward; The press rods 34 are connected to each other, and are arranged at a plurality of positions equally spaced in the circumferential direction of the outer lower die 5.

A bottomed cylindrical sleeve 35 with a closed end positioned upward is fixed to the upper holder part 14 of the lower die holder 13 with an axis extending in the vertical direction, and to the lower holder part 16,
A bottomed cylindrical sleeve 36 with its closed end positioned downward is fixed to the sleeve 35 with the same axis. Between these sleeves 35 and 36, a cylindrical rotating member 37 and a drive gear 32 that surrounds the rotating member 37 in a relatively unrotatable manner are rotatably supported around their axes. Further, the screw shaft 31 has both sleeves 35
．． 36 so as to be freely movable in the axial direction thereof, and is carved on the outer surface of the intermediate portion of the screw shaft 31.
is a female threaded portion 37 carved on the inner surface of the rotating member 37.
It is screwed into a. Furthermore, a driven gear 33 that meshes with the drive gear 32 is carved on the outer surface of the outer lower die 5 over a predetermined angular range, and the drive gear 32 is rotationally driven in accordance with the axial movement of the screw tenth 1-31. According to the rotation of the drive gear 32, the driven gear 33, that is, the outer lower die 5 is rotationally driven.

An engaging portion 31b with a non-circular cross section is provided at the lower part of the screw shaft 31, and this retaining portion 31b
is inserted into the closed end of the sleeve 36 so as to be freely movable in the axial direction, thereby preventing the screw shaft 31 from rotating. Further, a cylinder 38 having a piston rod 38a facing the lower end surface of the screw shaft 31 is disposed coaxially with the screw shaft 31 on the lower die plate 11, and the screw shaft 31 pressed down by the pressing rod 34 is disposed coaxially with the screw shaft 31. is pushed upward by the expansion operation of the cylinder 38.

In FIG. 3, a guide groove 39 is provided in the outer lower die 5 to guide the rotation of the outer lower die 5, and a roller 40 is pivotally supported in the inner lower die 4 to roll within the guide groove 39. be done. The guide groove 39 is connected to the outer lower die 5.
They are provided at a plurality of positions equally spaced in the circumferential direction on the lower inner surface of the outer lower die 5, and are formed corresponding to the finishing tooth molds 2o in the outer lower die 5.

The upper diamond has a shape corresponding to the upper surface of the intermediate molding material 1 on its lower surface and is basically formed in a cylindrical shape. An upper die holder 44 is fixed to the upper die holder 44 via an upper die plate 43 to the upper die set plate 42 which can be raised and lowered by being connected to a lifting drive means (not shown). The upper diamond is held allowing for relative movement. Further, a cylindrical stripper 45 that coaxially surrounds the upper diameter is held in the upper guide holder 44 so as to be relatively movable up and down. That is, in the center of the upper guide holder 44, there are a small diameter hole 46 and a medium diameter hole 4.
7 and a large-diameter hole 48 are coaxially drilled in order from above, and a regulating ring 49 that extends inward from the inner surface of the medium-diameter hole 47 is provided at the step between the medium-diameter hole 47 and the large-diameter hole 48. Fixed. The upper diamond is guided so as to be vertically movable by the regulating ring 49, and a flange 7a provided at the upper end of the upper diamond is fitted into the medium diameter hole 47.

Therefore, the upper die is vertically movable relative to the upper die holder 44 within the range where the flange portion 1a abuts the regulation ring 49 and the stepped portion between the small diameter hole 46 and the medium diameter hole 47. Further, a guide flange 45a provided at the upper end of the stripper 45 extending outward in the radial direction is slidably fitted into the large diameter hole 48, and a guide flange 45a provided on the lower end surface of the upper die holder 44 extends inwardly from the large diameter hole 48. A protruding ring-shaped regulation plate 50 is fixed. Therefore, the stripper 45 is vertically movable relative to the upper guide holder 44 within the range where the guide collar 45a contacts the regulation ring 49 and the regulation plate 50. Furthermore, a cylinder 51 is interposed between the upper die holder 44 and the stripper 45, and the stripper 45 is biased downward by the cylinder 51.

A tooth portion 52 of a tooth trace extending in the axial direction is provided on the lower outer surface of the upper dia, and a tooth portion 53 that meshes with the tooth portion 52 is provided on the lower inner surface of the stripper 45.

A holding cylinder 54 having an axis extending vertically is fixed to the upper die plate 43, and a press rod 34 whose lower end surface can come into contact with the upper end surface of the screw shaft 31 can move vertically relative to each other within a limited range. is held by the holding cylinder 54. That is, the upper end of the pressing rod 34 is slidably fitted into the holding cylinder 54, and the flange 34a of the regulating control 4 that can come into contact with a regulating step 54a provided facing upward within the holding cylinder 54 presses. It is provided at the upper end of the rod 34.

Further, a cylindrical support body 56 is slidably fitted into a sliding hole 55 connected to the holding cylinder 54 and formed in the upper guide plate 43 via a bush 57, and is supported by this support body 56. The piston rod 58a of the cylinder 58 that has been moved is brought into contact with the upper end of the press rod 34, and the cylinder 58 elastically urges the support body 56 and the press rod 34 in a direction away from each other.

The synchronization interlocking mechanism 9 is provided between the upper end of the upper die and the upper end of the support body 56, and includes a punch slider 60 supported by the upper die holder 44 so as to be movable up and down while contacting the upper end of the upper die. and,
A slider 61 is supported between the upper die set plate 42, the upper die plate 43, and the upper guide holder 44 so as to be movable in the horizontal direction while having one end in sliding contact with the upper end of the punch slider 60; The cam blocks 62 and 63 are slidably fitted into the slide hole 55 in sliding contact with each other.

The punch slider 60 is basically formed in a cylindrical shape, and is disposed within the small diameter hole 46 so as to be movable in the vertical direction via a bush 64, and the lower end of the punch slider 60 abuts the upper end of the upper diameter. Also punch slider 60
A cam surface 65 that slopes downward toward the sides is provided at the upper end.

The slider 61 is disposed between a position corresponding to the upper dial and a position corresponding to the rotation drive mechanism 8, and has a cam surface 66 at one end that slides into contact with the cam surface 65. is provided. Further, the other end of the slider 61 is provided with a cam surface 67 that slopes downward toward the one end. The cam blocks 62 and 63 are slidably fitted into the sliding hole 55 while coming into contact with each other, and these cam blocks 62 and 63 include a cam that slides into contact with the cam surface 67 of the slider 61. Surface 68.69
are formed by being connected to each other.

According to such a synchronization interlocking mechanism 9, the contact of the upper diamond with the intermediate molding material 1 and the pressing down of the screw shaft 31 by the pressing rod 34 in the rotary drive mechanism 8 are synchronized. That is, when the upper diamond comes into contact with the intermediate forming material l and moves to the upper limit position relative to the upper guide holder 44, the synchronous interlocking mechanism 9 moves the support member 56
The relative lower limit position with respect to the upper die holder 44 is determined, and thereby the screw shaft 31 by the pressing rod 34
The pressing start time, that is, the operation start time of the rotary drive mechanism 8 is determined.

Referring to FIGS. 4 and 5 together, in the upper part of the finishing tooth mold 20 in the outer lower die 5, in order from above, there is a housing recess 71 that can accommodate the lower end of the upper die, and a molding target value. A first land 72 having a larger size and a second land 73 continuous to the lower end of the first run F72 are provided, and the second land 73 is formed to have a size corresponding to a molding target value. The accommodation recess 71 is formed so as to accommodate the tooth portion 52 of the upper die when the upper die descends to the lowest position in relation to the relative rotation of the outer lower die 5 with respect to the upper die. The intermediate forming material 1 is formed to have dimensions that allow the intermediate forming material 1 to be ironed with an ironing margin of a certain value or more regardless of variations in the dimensions.

Next, the procedure of ironing the intermediate molding material 1 using the molding device 3 will be described. First, the intermediate molding material 1 is placed on the lower die 6 with the asper die raised.

At this time, the rough tooth profile portion 2 of the intermediate forming material 1 is positioned by the first land 72 located above the finishing tooth profile 20 of the outer lower die 5.

Next, when the upper die set plate 42 is lowered, the intermediate forming material 1 is held between the inner lower die 4 and the upper die in the lower die 6, as shown in FIG. When the upper die set plate 42 is further lowered in this state, the intermediate forming material 1 is pushed into the outer lower die 5 while being held between the inner lower die 4 and the upper die.

The pressing rod 34 is lowered by lowering the upper decent plate 42.
Since the outer lower die 5 is also lowered, the outer lower die 5 is driven to rotate in synchronization with the pushing of the intermediate forming material 1 by the action of the rotation drive mechanism 8. Therefore, the outer lower die 5 and the inner lower die 4 rotate relative to each other in the torsional direction in synchronization with the lowering of the intermediate forming material l, and this relative rotation causes the coarse tooth profile portion 2 to be formed in the finishing tooth die 20. It's gone. Furthermore, the relative rotation between the inner lower die 4 and the inner lower die 5 is smoothly performed by the functions of the guide grooves 39 and the rollers 40.

During this ironing, the rough tooth profile portion 2 is first formed on the first land 72.
The first land 73 is then squeezed by the second land 73.

Therefore, even if there is some variation in the dimensions of the intermediate forming material 1, highly accurate tooth forming can be performed while avoiding bending or falling of the teeth. In addition, since the first and second lands 72 and 73 are ironed continuously, work hardening of the material of the intermediate molding material 1 is avoided, and smooth ironing processing that does not require bonderite treatment is possible.

Moreover, counter pressure from a plurality of cylinders 25 acts on the inner lower die 4 during the above molding.

As a result, a forming load and a load due to a counter pressure opposing the forming load act on the rough tooth profile portion 2, and the rough tooth profile portion 2 is formed in a balanced state of the loads. Furthermore, since the inner lower die 4 is rotatably supported by the support plate 23 via the thrust bearing member 24, no rotational force or bending force is applied to each cylinder 25, thereby avoiding seizure or galling. cylinder 25
can maintain smooth operation.

Further, when the intermediate forming material 1 is pushed down by the upper diamond, the rotational movement of the rotation drive mechanism 8 is performed by the synchronization interlocking mechanism 9 in synchronization with the lowering of the intermediate forming material 1 by the upper diamond, so that the intermediate forming material 1 is pressed down. Even if there is some variation in the axial thickness, accurate molding using the finishing tooth mold 20 is possible.

After the molding is completed, the upper die set plate 42 is driven upward, and then the inner lower die 4 is moved through the support plate 23 and the bearing member 24 by the upward force of the piston rod 25a.
is raised to separate the molded product from the outer lower die 5, and the knockout pin 28 is driven upward, and the knockout pin 28 pushes the lower bunch 26 upward, causing the molded product to be released from the inner lower die 4. Forced to leave.

Here, a specific example of ironing according to the present invention is as follows.

The material is SCM40.5Cr420, and the tooth tip diameter is 76+nmΦ and the number of teeth is 2 by hoshito shaving molding etc.
7-29. Prepare an intermediate molding material compatible with a module 2.5 involute helical gear with a helix angle of 36 degrees, and iron the intermediate molding material with a 100-200 Ton press at a counter pressure of 3-8 kg/mm2. Teenage 0
．． Ironing was carried out under conditions of 0.02 to 0.06 mm.

At this time, if the circumferential surface roughness of the tooth part is R1 and the axial roughness is R2, the product accuracy of No. 011 and No. 2 is D.
The target values corresponding to IN grade 9 were shown in the numerical table, and it was found that accuracy could be maintained up to a mold life of 20,000 to 50,000 shots.

As can be seen from this result, by ironing according to the present invention, it is possible to obtain a helical gear with sufficiently high precision.

C1 Effects of the Invention As described above, according to the present invention, the finish includes a first land having a dimension larger than the forming target value, and a second land having a dimension corresponding to the forming target value and continuous to the first land. A tooth profile is provided in the die, and the intermediate forming material is pushed into the die while applying counter pressure, and the coarse tooth profile part is ironed by the first land with an ironing amount of more than a certain value, and then the rough tooth profile part is ironed by the second land. Since the toothed portion is squeezed, even if there is some variation in the dimensions of the intermediate molded material, the molding accuracy can be improved and the molding action can be carried out smoothly.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal cross-sectional view of a molding apparatus, and
The figure is a sectional view taken along the line ■-■ in Figure 1, and Figure 3 is a cross-sectional view taken along the line ■-■ in Figure 1.
Line sectional view, Figure 4 is an enlarged view of the ■ part in Figure 1, Figure 5 is the
It is a sectional view taken along the line ■-V in the figure. DESCRIPTION OF SYMBOLS 1... Intermediate molding material, 2... Rough tooth profile part, 5... Outer lower die, 20... Finishing tooth mold, 72... First
Land, 73...2nd land

Claims (1)

[Claims] A gear that is ironed by pressing an intermediate forming material formed by roughly forming the rough tooth profile part of a helical gear such as a helical gear with a non-linear tooth trace on the outer periphery into a die having a finishing tooth profile. In the tooth profile ironing method, the die is provided with a finishing tooth shape that includes a first land having dimensions larger than a forming target value and a second land having dimensions corresponding to the forming target value and continuous with the first land. , the intermediate forming material is pushed into the die while applying counter pressure, and the coarse tooth profile part is pressed with a certain amount or more of ironing by the first land, and then the second land is pressed.
A method for ironing gear tooth profiles, which is characterized by squeezing rough tooth profile parts with lands.