JP4139277B2 - Gear finishing forging equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gear finishing forging device for precisely finishing gear teeth by forging.
[0002]
[Prior art]
A conventional technique is shown in FIG. In FIG. 3, 1 is a finish forging device, and 2 is a deposit supported by a machine base (not shown). An annular die holder 4 surrounded by a clamp 3 is placed on the top of the deposit 2. The inner surface of the die holder 4 is formed in a tapered hole 4a that shrinks downward, and an annular die 5 is taper fitted into the tapered hole 4a. The die 5 is formed with gear forming teeth 5a for finishing on the inner periphery, and the coarse teeth 10a of the workpiece 10 are finished by the gear forming teeth 5a. The workpiece 10 has a ring shape, and the coarse teeth 10a have a predetermined press-fitting allowance with respect to the gear forming teeth 5a.
[0003]
6 is a core bar which is erected fixed on a machine base side, the die holder 4, and passes through the axial center of the die 5, the upper end is protruded by a predetermined amount above the die 5, the workpiece 10 in this part Are fitted, and the fitted workpiece 10 is guided toward the die 5. A cylindrical knockout 7 is fitted to the outer periphery of the cored bar 6. At the time of molding, the knockout 7 has its upper end positioned below the die 5 to set the lower limit position of the workpiece 10, and after molding, moves upward to disengage the molded gear from the die 5. It is like that.
[0004]
A punch unit 8 is disposed above the die 5. The punch unit 8 includes a small-diameter and cylindrical first punch 8a and a large-diameter and cylindrical second punch 8b fitted to the outer periphery of the first punch 8a. The first punch 8a presses and moves the work 10 fitted to the metal core 6 downward and press-fits it into the die 5, and the second punch 8b is positioned a predetermined amount above the first punch 8a. When the entire area of the workpiece 10 is press-fitted into the die 5, the die 5 is moved downward under pressure, and the die 5 is elastically deformed in the axial direction by the tapered hole 4a of the die holder 4, and is shown in the right half part of FIG. In this way, the gear forming tooth 5a is pressed against the coarse tooth 10a of the workpiece 10 to obtain a gear 10 ′ having a tooth 10a ′ to which the gear forming tooth 5a is transferred. 8c is a punch holder fitted to the outer periphery of the second punch 8b for colliding with the upper end of the clamp 3 when set down to set the lower limit positions of the first punch 8a and the second punch 8b. Is. When the lower limit position is set by a ram (slide) that moves the punch unit 8 up and down, the collision of the punch holder 8c with the upper end of the clamp 3 is stopped.
[0005]
[Problems to be solved by the invention]
In the above-described conventional one, when the coarse teeth 10a have a large diameter or the press-fitting allowance of the coarse teeth 10a increases and the pressure input of the coarse teeth 10a to the gear forming teeth 5a increases, the workpiece by the first punch 8a is increased. When the die 10 is lowered, the die 5 is deeply fitted into the die holder 4 when the entire area of the coarse tooth 10a is press-fitted into the gear forming tooth 5a. For this reason, the amount of lowering of the die 5 by the second punch 8b and hence the amount of elastic deformation of the die 5 in the axial direction is small in the final forming stage in which the workpiece 10 is compressed in the axial direction by the first punch 8a and the knockout 7. Thus, the transfer of the gear forming teeth 5a, that is, the finish forming of the teeth becomes unstable. In particular, as shown in the right half of FIG. 3, when the die 5 reaches the fitting position S that exceeds the molding completion reference position M in the die holder 4 in the ironing stage, the lower limit of the upper surface of the die 5 and the second punch 8b. A gap C is generated between the first punch 8a and the knockout 7, and the die 5 is lowered by the second punch 8b in the final molding stage in which the workpiece 10 is compressed in the axial direction. No elastic deformation is performed at all, and the tooth can not be finish-molded by the gear forming teeth 5a. SUMMARY OF THE INVENTION An object of the present invention is to provide a gear finishing forging device having a stable forming accuracy by giving a predetermined resistance when a die moves to a small diameter side of a tapered hole.
[0006]
[Means for Solving the Problems]
The present invention is configured as follows to achieve the above object. That is, in the invention according to claim 1, a gear forming tooth is formed on the inner periphery and a die having an outer periphery formed on a tapered surface is slidably taper-fitted into the taper hole of the die holder, A workpiece formed with press-fitting coarse teeth, and a first punch for press-fitting the workpiece into the die from one end on the large diameter side to the other end, and located on the reverse side with respect to the first punch; And a gear forging device having a second punch capable of coming into contact with the large-diameter side end face of the die, wherein the outer periphery has a tapered surface substantially corresponding to the small-diameter side end of the tapered hole. the provided a resistive element antibodies smaller diameter end of the tapered hole, causes slidably taper fitted to the taper hole by spaced larger diameter from the small diameter side end face of the tapered hole, the resistive element antibodies The large diameter side end face is the small diameter of the die Is abutted against the end surface, the frictional resistance to a die holder 23 of the resistor 25 is, when the entire area of the workpiece 35 is press-fitted into the die 24 by the first punch 33a, the movement amount of the small-diameter direction of the die 24 against the die holder 23 Is positioned on the larger diameter side with respect to the molding completion reference position M.
According to a second aspect of the present invention, a small diameter tapered hole and a large diameter tapered hole inclined in the same direction are formed in a step shape in the axial center portion of the die holder, and the die can slide in the small diameter tapered hole. And a resistor having an outer periphery formed on a tapered surface substantially corresponding to the tapered hole of the large diameter, and the resistor is formed into the tapered hole of the large diameter and the small diameter side of the tapered hole of the large diameter The resistor is slidably tapered away from the end face toward the large diameter side, and the large diameter end face of the resistor is brought into contact with the small diameter end face of the die .
According to a third aspect of the present invention, there is provided an elastic body that presses and urges the resistor against the die holder in the direction of the diameter of the tapered hole.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. In the figure, FIG. 1 is a sectional view for explaining a forging device showing a first embodiment of the present invention, and FIG. 2 is a sectional view for explaining a forging device showing a second embodiment of the present invention.
[0008]
In FIG. 1, 20 is a finish forging device for gears, and 21 is a metal pad fixed to the machine base. A clamp 22 and a die holder 23 that is press-fitted and fixed to the axial center of the clamp 22 are placed on the upper surface of the deposit 21, and a metal die 24 is vertically slid on the inner periphery of the axial center of the die holder 23. The taper fits so that it can move. The die 24 has finishing gear forming teeth 24a formed on the inner periphery, and the gear forming teeth 24a finish the coarse teeth 35a of the work 35. The workpiece 35 has a ring shape, and the coarse teeth 35a have a predetermined press-fitting allowance with respect to the gear forming teeth 24a.
[0009]
The taper hole 23a of the die holder 23 to which the die 24 is taper-fitted is a taper hole that shrinks downward, and the taper surface 24b of the outer peripheral surface of the die 24 that taper-fits the taper hole 23a is also downward. Reduced taper surface. In this example, the taper angle of the taper surface 24b is made slightly smaller than that of the taper hole 23a so that the lower side of the die 24 abuts more strongly than the upper side. An annular oil groove 24c is formed on the tapered surface 24b of the die 24 at a predetermined interval in the vertical direction, and lubricating oil is supplied to this portion to stabilize the vertical sliding in the die holder 23 of the die 24. .
[0010]
The tapered hole 23a of the die holder 23 is longer than the die 24 so that the die 24 slides up and down on the upper side of the tapered hole 23a. Then, the resistor 25 forming a resistance device is taper-fitted to the lower side of the taper hole 23a so as to be slidable up and down. The resistor 25 is made of the same metal material as that of the die 24, and has an outer peripheral surface formed on a tapered surface 25a substantially corresponding to the tapered hole 23a, and an upper surface thereof is brought into contact with a lower surface of the die 24.
[0011]
An elastic body 26 made of a compression coil spring is disposed between the lower surface of the resistor 25 and the metal plate 21, and the elastic body 26 moves the resistor 25 and the die 24 upward, that is, in the large diameter direction of the tapered hole 23a. Press to energize. A stopper ring 27 is fixed to the upper part of the clamp 22 with a screw to prevent the die 24 from coming out upward from the tapered hole 23a. In addition, the tooth profile of the gear forming tooth 24a formed on the inner periphery of the die 24 is appropriately set to a flat tooth shape, a crown tooth shape, a helical tooth shape, a helical crown tooth shape, or the like according to the type of gear to be formed.
[0012]
30 is a core bar standing upright fixed to the machine base side, the die holder 23, and passes through the axial center of the die 24, the upper end is protruded by a predetermined amount above the die 24, the workpiece 35 as described above in this section Mate. A cylindrical knockout 31 is fitted to the outer periphery of the core metal 30, and the knockout 31 has its upper end positioned at the lower part of the die 24 at the time of molding to set the lower limit position of the work 35, and after molding, The gear formed by moving upward is separated from the die 24 upward.
[0013]
A punch unit 33 that is moved up and down by a ram (not shown) is disposed above the die 24. The punch unit 33 includes a small-diameter and cylindrical first punch 33a and a large-diameter and cylindrical second punch 33b fitted to the outer periphery of the first punch 33a. The first punch 33a protrudes a predetermined amount below the second punch 33b, and the work 35 fitted to the core metal 30 is pressed and moved downward by the first punch 33a to press fit into the die 24. The second punch 33b is configured to pressurize and move the die 24 downward when the entire area of the work 35 is press-fitted into the die 24 by the first punch 33a. Reference numeral 33c denotes a punch holder fitted to the outer periphery of the second punch 33b, which collides with the upper end of the clamp 22 when moved downward to set the lower limit positions of the first punch 33a and the second punch 33b. When the lower limit position is set by a ram (slide) that moves the punch unit 33 up and down, the collision with the upper end of the clamp 22 by the punch holder 33c is stopped.
[0014]
FIG. 2 shows a second embodiment. In this device, a small diameter tapered hole 23a and a large diameter tapered hole 23b are formed in a step shape in the upper and lower portions of the axial center portion of the die holder 23, and the die 24 is slid up and down in the upper tapered hole 23a. The large-diameter resistor 25-1 is taper-fitted so as to be slidable up and down in a tapered hole 23b on the lower side. The taper angles of the taper holes 23a and 23b are substantially the same. In this way, the length of the resistor 25-1 can be reduced and the device can be made smaller. The other structure is substantially the same as that of the first embodiment.
[0015]
Here, the vertical lengths and diameters of the tapered surfaces of the resistors 25 and 25-1, and the frictional resistance force of the resistors 25 and 25-1 against the die holder 23 are set as follows. That is, when the workpiece 35 is lowered by the first punch 33a and the entire area of the rough teeth 35a is press-fitted into the gear forming teeth 24a of the die 24, the lowering amount (fitting amount) of the die 24 with respect to the die holder 23 is formed. The descent amount is 30% to 50% with respect to the completion reference position M.
[0016]
According to the above embodiment, when the work 35 is press-fitted into the die 24 by the first punch 33 a, the die 24 is dragged downward by the work 35 and tries to move downward in the die holder 4. At this time, since the resistor 25 (25-1) exists on the lower surface side of the die 24, the resistor 25 restricts a large downward movement of the die 24, and the fitting amount of the die 24 with respect to the die holder 23 Is a sufficient upper position with respect to the molding completion reference position M. Further, when the workpiece 35 is fitted into the die 24, the coarse teeth 35 a are crushed by the gear forming teeth 24 a of the die 24 and are formed on a smooth surface.
[0017]
When the punch 33 is further lowered, the second punch 33b collides with the upper surface of the die 24, and finish molding of teeth is started from this point. That is, while the work 35 is compressed in the axial direction by the first punch 33a and the knockout 31, the die 24 is moved downward by the second punch 33b, and the die 24 is elastically deformed to a small diameter by the taper hole 23a of the die holder 23. Therefore, the gear forming teeth 24a press the coarse teeth 35a of the workpiece 35 in the axial direction. When the punch 33 further descends and the punch holder 33c collides with the upper surface of the clamp 22 as shown in the right half of FIGS. As a result, when the workpiece 35 is compressed in the axial direction by the first punch 33a and the knockout 31, the amount of downward movement of the die 24 by the second punch 33b increases, and the teeth 35a 'of the formed gear 35' The tooth mold of the gear forming teeth 24a is transferred with high accuracy and high accuracy. Further, the completion of the finish molding is always performed at the molding completion reference position M of the die 24, and the gear 35 'having a stable dimension is obtained.
[0018]
【The invention's effect】
As is apparent from the above description, the invention according to claim 1 is provided with a resistor that restricts the movement of the die when the die moves in the small diameter direction through the tapered hole of the die holder. Finish molding of coarse teeth with a large press allowance can be performed with high accuracy and stability.
In addition, since the resistor whose outer periphery has a tapered surface is slidably taper-fitted into the taper hole of the die holder on the small diameter side of the die, the structure becomes simple and can be obtained at low cost.
In the invention according to claim 2 , since the diameter of the upper part of the tapered surface of the resistor is made larger than the diameter of at least the lower part of the tapered surface of the die, the length of the resistor is reduced and the device is made compact. Can do.
Further, the invention according to claim 3 is provided with an elastic body that presses and urges the resistor in the large diameter direction of the tapered hole with respect to the die holder, so that the resistor always adheres to the die and imparts resistance to the die. Will be stable.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view for explaining a forging device showing a first embodiment of the present invention.
FIG. 2 is an explanatory sectional view of a forging device showing a second embodiment of the present invention.
FIG. 3 is an explanatory sectional view of a forging device showing a conventional example.
[Explanation of symbols]
20 Gear Finishing Forging Equipment 21 Deposits 22 Clasps 23 Die Holders 23a, 23b Tapered Holes 24 Dies 24a Gear Molding Teeth 24b Tapered Surfaces 24c Oil Grooves 25 (25-1) Resistors (resistance devices)
25a Tapered surface 26 Elastic body 27 Stopper ring 30 Core metal 31 Knockout 33 Punch unit 33a First punch 33b Second punch 33c Punch holder 35 Work 35a Coarse teeth

Claims (3)

A die (24) having a gear forming tooth (24a) formed on the inner periphery and an outer periphery formed on a tapered surface (24b) is slidably taper-fitted into the taper hole (23a) of the die holder (23), A workpiece (35) having coarse teeth (35a) that can be press-fitted into the gear forming teeth (24a) is provided, and the workpiece (35) is directed to the die (24) from one end on the large diameter side to the other end. A first punch (33a) to be press-fitted, and a second punch (33b) that is positioned on the reverse side with respect to the first punch (33a) and that can be brought into contact with the large-diameter end surface of the die (24). In the gear finishing forging device provided, a resistor (25) having an outer periphery formed on a tapered surface (25a) substantially corresponding to a small diameter side end of the tapered hole (23a) is provided, and the resistor (25) The small diameter of the taper hole (23a) The end, from the small-diameter side end surface by spaced larger diameter causes slidably taper fitted to the taper hole (23a), the large diameter side end face of the resistive element antibodies (25) of the tapered hole (23a) Is brought into contact with the end face on the small diameter side of the die (24), and the friction resistance force of the resistor (25) against the die holder (23) is applied to the entire area of the work (35) by the first punch (33a). The gear is characterized in that the amount of movement of the die (24) in the small diameter direction relative to the die holder (23) is positioned on the large diameter side with respect to the molding completion reference position (M) when being pressed into the die. Finishing forging equipment. A small diameter taper hole (23a) and a large diameter taper hole (23b) inclined in the same direction are formed in a step shape in the axial center of the die holder (23), and the die ( 24) is slidably taper-fitted, and a resistor (25-1) having an outer periphery formed on a tapered surface (25a) substantially corresponding to the large-diameter taper hole (23b) is provided. 25-1) is slidably taper-fitted to the large diameter tapered hole (23b) so as to be separated from the small diameter side end face of the large diameter tapered hole (23b) toward the large diameter side, and the resistor The gear finishing forging device according to claim 1 , wherein the large-diameter side end surface of (25-1) is brought into contact with the small-diameter side end surface of the die (24) .   The gear according to claim 1 or 2, further comprising an elastic body (26) that presses and urges the resistor (25) against the die holder (23) in the direction of the diameter of the tapered hole (23a). Finishing forging device.

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