JP2007203374A - Method for manufacturing crowning gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a method for manufacturing a crowning gear, wherein the crowning gear can be formed with a forging having high productivity. <P>SOLUTION: A finishing die (42) where the side surface of an inner tooth (42a) is formed in the reversed crown-shape, and a primary gear (46) where the outer tooth (46a) is formed so as to have nearly equal tooth thickness over the whole length, are arranged, and the finishing die (42) is tapered-fitted to a fastening metal (39) and also, a shaft end part of the finishing die (42), in which the tapered surface becomes the large diameter, is abutted on a stopper die (36). Then, each tooth (46a) of the primary gear (46) is fitted into each teeth interval of the finishing die (42) and only the fastening metal (39) is shifted with a punch (38) in the axial direction, in which the tapered surface becomes the large diameter, to the finish die (42), and the finishing die (42) is elastically deformed into the small diameter, and each tooth (46a) of the primary gear (46) is formed in the crown-shape by pressing this each tooth (42a) to each tooth (46a) of the primary gear (46). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a crowning gear for forging a crowning gear in which the tooth thickness of external teeth gradually increases from the longitudinal ends toward the center.

  When the crowning gear is formed by forging, it has been difficult to process the inner teeth into anti-crown teeth, so the teeth of the coarsely processed gear (external gear) are ground with a gear grinder or the like to remove the crowning gear. I was trying to get it.

  The above conventional products have poor productivity and require skill in processing. An object of this invention is to obtain the manufacturing method of a crowning gear which can shape | mold a crowning gear by forging with high productivity.

The present invention is configured as follows to achieve the above object. That is, the invention according to claim 1 is provided with a finish mold in which the side surfaces of the inner teeth are formed in an anti-crown shape, and a primary gear in which the outer teeth are formed with substantially equal tooth thickness over the entire length. The die is taper-fitted to the clamp, and the shaft end with the taper surface having a large diameter is brought into contact with the stopper die, and the teeth of the primary gear are fitted between the teeth of the finishing die, and the punch To move only the clamp in the axial direction where the taper surface has a large diameter with respect to the finish mold, and elastically deform the finish mold to a small diameter by the clamp to move each tooth of each primary gear. Each tooth of the primary gear is formed into a crown shape by being pressed against the teeth.
According to a second aspect of the present invention, each tooth of the primary gear is a helical tooth, and each tooth of the finishing mold is a helical anti-crown tooth in which each helical tooth of the primary gear is fitted.

In the invention according to claim 1, the finish gear is fitted to a primary gear whose outer teeth are formed to have substantially equal tooth thickness over the entire length, and in this state, the finish die is elastically deformed to a small diameter. Since each tooth is pressed against each tooth of the primary gear and the side surface of each tooth of the primary gear is formed into a crown shape, if the primary mold is elastically restored, the product is removed from the finish mold. It can be pulled out in the axial direction, and the crowning gear can be easily manufactured by forging.
In the invention according to claim 2, each tooth of the primary gear is a helical tooth, and each tooth of the finishing mold is a helical anti-crown tooth to which each helical tooth of the primary gear is fitted. It can be easily manufactured by forging.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a processing state of a primary mold according to the present invention, FIG. 2 is a cross-sectional view for explaining a tooth part of FIG. 1, FIG. 3 is a cross-sectional view for explaining a tooth part of a primary mold, and FIG. FIG. 5 is a sectional view for explaining the tooth portion of FIG. 4, FIG. 6 is an enlarged sectional view taken along VI-VI of FIG. 5, and FIG. 7 is a sectional view of the primary gear according to the present invention. FIG. 8 is a sectional view showing the machining state of the crowning gear according to the present invention, FIG. 9 is a sectional view for explanation showing the state of the tooth part according to FIG. 8 before machining, and FIG. 10 is the tooth according to FIG. It is sectional drawing for description which shows the processing state of a part.

  In FIG. 1, reference numeral 1 denotes a first electric discharge machine that molds a primary mold 41, and a holding device 2 that holds a ring-shaped mold material 40 and helical teeth 41 a are formed on the inner periphery of the held mold material 40. The coarse-tooth electrode 10 is provided. The holding device 2 is as follows. That is, the cylindrical clamp 4 and the pressure receiving plate 5 are arranged vertically at the center of the outer case 3 supported on the base side, and are press-fitted and fixed. The fitting hole 4a formed in the axial center portion of the clamp 4 is a tapered hole whose inner diameter is gradually reduced from the upper part toward the lower part, and the cylindrical mold material 40 is taper-fitted into the fitting hole 4a. .

  A pressurizing device 6 is provided on the upper side of the outer case 3. The pressure device 6 has a ring-shaped holder 8 and a pressure ring 9 attached to the lower part of a vertically moving punch 7 in an overlapping manner. The ring-shaped holder protrudes downward from the inner peripheral lower part of the pressure ring 9. A projection 9a is formed, and when the punch 7 moves downward, the mold material 40 is pressed downward by the projection 9a, and the mold material 40 is engaged with the clamp 4 with a predetermined frictional force.

  The coarse tooth electrode 10 described above is formed with helical teeth 10a having a uniform tooth thickness over the entire length of the outer circumference of the cylindrical electrode body. The coarse tooth electrode 10 is formed on the axial center portion of the punch 7 described above. The holder 11 is suspended and supported via the holder 11 and is moved downward while reciprocating in the vertical direction at an angle equal to the torsion angle of the helical tooth 10a. Then, while energizing the coarse electrode 10, the coarse electrode 10 is moved downward (arrow A) through the holder 11 while reciprocating in the vertical direction as shown in FIG. The inner periphery of the raw material 40 is subjected to electric discharge machining, and as shown in FIG. 3, a primary mold 41 having helical teeth 41a on the inner periphery is obtained. In addition, you may make it form the helical tooth | gear 41a of this primary metal mold | die 41 with a hobbing machine.

  In FIG. 4, reference numeral 15 denotes a second electric discharge machine for forming the finishing die 42, the holding device 2 for holding the primary die 41 described above, and the helical teeth of the primary die 41 held by the holding device 2. A helical crown tooth electrode 16 is formed to form 41a on a helical anti-crown tooth 42a. The holding device 2 has substantially the same structure as described above. That is, a cylindrical clamp 4 and a pressure receiving plate 5 are vertically arranged at the center of the outer case 3 supported on the base side and are press-fitted and fixed. The fitting hole 4a of the clamp 4 has an inner diameter from the top to the bottom. A taper hole that gradually decreases toward the fitting hole 4a, and the above-described primary mold 41 is taper fitted into the fitting hole 4a.

  The pressure device 6 provided on the upper side of the outer case 3 has a ring-shaped holder 8 and a pressure ring 9-1 attached to the lower portion of the punch 7 that is moved up and down in a stacked manner. The pressurizing ring 9-1 forms a ring-shaped protrusion 9-1a protruding downward at the inner peripheral lower portion thereof. The downward protrusion amount of the protrusion 9-1a is larger than the protrusion 9a of the pressure ring 9 described above, and the primary metal taper-fitted to the clamp 4 by the protrusion 9a when the punch 7 moves downward. The mold 41 is pressed and moved downward by a predetermined amount so that the primary mold 41 is elastically deformed to a small diameter.

  The aforementioned helical crown tooth electrode 16 is formed by forming helical crown teeth 16a at a predetermined pitch on the outer periphery of a cylindrical electrode body. The helical crown teeth 16a have the same twist angle as that of the helical teeth 41a of the primary mold 41 described above, and the side shape of the helical crown teeth 16a is the same as that of the helical crown gear teeth. The helical crown teeth 16a have a pitch and a tooth thickness that are loosely fitted between the helical teeth 41a of the primary mold 41.

  The helical crown tooth electrode 16 is suspended and supported by the holder 11 disposed at the axial center of the punch 7 described above, and the crown tooth electrode 16a is placed through the holder 11 at a predetermined angle in the circumferential direction, in this example, in the circumferential direction. The reciprocating rotation is performed at an angle of 0.01 mm to 0.02 mm. Then, as shown in FIG. 4, the helical crown tooth electrode 16 is fitted to the axial center portion of the primary mold 41 held by the holding device 2, and the helical crown teeth 16 a are connected to the helical molds of the primary mold 41. While meshing between the teeth 41a and energizing the helical crown tooth electrode 16 in this state, the helical crown tooth electrode 16 is passed through the holder 11 in the circumferential direction as shown in FIGS. By rotating and reciprocating at an angle of .02 mm (arrow B), each helical tooth 41a of the primary mold 41 is subjected to electric discharge machining, and the side surface shape of each tooth corresponds to the side surface shape of the tooth 16a of the helical crown tooth electrode 16. A finished mold 42 to be the helical anti-crown tooth (inner tooth) 42a is obtained.

  In FIG. 7, reference numeral 20 denotes an extrusion molding machine that molds the primary helical gear 46, and includes a cylindrical container 21 that forms helical teeth on the outer periphery of the accommodated material 45 and a punch 27 that pushes the material 45 in the container 21 downward. Have. The container 21 has helical shaped teeth 21a projecting in the axial direction on the inner periphery of the lower portion thereof. The formed tooth 21a has its tooth thickness and tooth height gradually increased from the upper side toward the lower side, the outer periphery thereof is surrounded by the clamp 22 and placed on the pressure receiving plate 23, and both are placed by the outer case 24. Connected to the cradle 25 for rotation.

  A shaft-shaped mandrel 26 is fitted into the shaft center portion of the container 21 while maintaining a predetermined gap, and this is supported upright and rotatably on the base side. The mandrel 26 is fitted into the central portion of the cylindrical material 45, and the cross-sectional reduction rate of the material 45 is adjusted by changing its diameter.

  The punch 27 has a cylindrical shape that fits between the container 21 and the mandrel 26, and is supported by the ram (not shown) so as to be rotatable. Then, a plurality of materials 45 are vertically stacked and fitted between the container 21 and the mandrel 26, and the material 45 is moved downward by the punch 27 to pass through the molding tooth 21a portion of the container 21. As a result, as shown by the phantom line in FIG. 7, the primary helical gear 46 having helical teeth 46 a having an equal tooth thickness over the entire length is obtained.

  Next, the helical teeth 46a of the primary helical gear 46 are formed on the helical crown teeth 47a by the finishing die 30 shown in FIG. The finishing die 30 has a cylindrical die case 32 whose outer periphery is reinforced by an inner case 33 and an outer case 34 attached to the upper portion of the pressure receiving plate 31, and is clamped by a punch 38 in the die case 32. The gold 39 is slidably fitted. The clamp 39 has a tapered hole 39a having a large diameter on the lower side in the shaft center portion, and the above-described finishing mold 42 can be taper-fitted into the tapered hole 39a.

  The diameter of the tapered hole 39a of the clamp 39 is slightly smaller than the tapered surface on the outer periphery of the finish mold 42, and the lower end of the clamp 39 is slightly smaller than the lower end of the finish mold 42 as shown by the phantom line in FIG. The taper surfaces of both are brought into close contact with each other when positioned above. A cylindrical stopper die 36 for receiving the finishing die 42 is disposed on the shaft center portion of the pressure receiving plate 31 and is fixed upright on the base side, and is supported upright on the shaft side portion of the clamp 39 on the base side. The shaft-shaped metal core 37 is fitted with a predetermined gap.

  Then, the above-described primary helical gear 46 is fitted into the finishing mold 42, and the helical teeth 46a thereof are fitted between the helical anti-crown teeth 42a of the finishing mold 42. In this state, the primary helical gear 46 is fitted. Is inserted into the core metal 37 and fitted into the die case 32 together with the finishing die 42, and the lower surface of the finishing die 42 is brought into contact with the upper surface of the stopper die 36.

  In this state, as shown by a solid line in FIG. 8, the clamp 39 is lowered through the punch 38 to a position where the lower surface of the clamp 39 comes into contact with the upper surface of the stopper die 36. The mold 42 is elastically deformed to a small diameter. As a result, the helical anti-crown teeth 42a of the finishing mold 42 change from the pitch shown in FIG. 9 to a small pitch and a small diameter as shown in FIG. 10, and the helical anti-crown teeth 42a of the primary helical gear 46 are changed. Each tooth 46a is pressed into contact with each tooth 46a and is plastically deformed into helical crown teeth 47a whose tooth thickness gradually increases from the upper and lower ends toward the center, and a desired product, that is, a helical crowning gear 47, as shown in FIG. Can be obtained.

  When the punch 38 is moved upward after the helical crown gear 47 is formed, the clamp 39 is moved upward, the finishing die 42 is elastically returned to a large diameter, and the internal helical crown gear 47 can be taken out. it can. In the present invention, the crowning gear whose teeth extend linearly in the axial direction can also be formed by forging. In this case, the helical tooth 10a of the coarse tooth electrode 10 of the primary electric discharge machine 1 described above is a flat tooth extending in the axial direction, and the helical crown tooth 16a of the crown tooth electrode of the second electric discharge machine 16 is a crown tooth extending in the axial direction. In addition, the molding teeth 21a of the container 21 of the extrusion molding machine 15 need to be changed into flat teeth molding teeth extending in the axial direction.

It is sectional drawing which shows the processing state of the primary metal mold | die by this invention. It is sectional drawing for description of the tooth | gear part of FIG. It is sectional drawing for description of the tooth | gear part of a primary metal mold | die. It is sectional drawing which shows the processing state of the finishing metal mold | die by this invention. It is sectional drawing for description of the tooth | gear part of FIG. It is an expanded sectional view by VI-VI of FIG. It is sectional drawing which shows the processing state of the primary gear by this invention. It is sectional drawing which shows the processing state of the crowning gear by this invention. It is sectional drawing for description which shows the state before the process of the tooth | gear part by FIG. It is sectional drawing for description which shows the processing state of the tooth | gear part by FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Primary electric discharge machine 2 Holding device 3 Outer case 4 Clamp 4a Fitting hole 5 Pressure receiving plate 6 Pressurizing device 7 Punch 8 Holder 9 (9-1) Pressurizing ring 9a (9-1a) Protrusion 10 Coarse tooth electrode 10a Helical tooth 15 Second electrical discharge machine 16 Crown tooth electrode 16a Helical crown tooth (external tooth)
20 Extruder 21 Container 22 Clamp 23 Outer Case 24 Pressure Plate 25 Receptacle 26 Mandrel 27 Punch 30 Finishing Mold 31 Pressure Plate 32 Die Case 33 Inner Case 34 Outer Case 35 Clamp 36 Stopper Die 37 Core Bar 38 Punch 39 Clamp 39a Taper hole 40 Mold material 41 Primary mold 41a Helical teeth (inner teeth)
42 Finishing mold 42a Helical anti-crown tooth (inner tooth)
45 Material 46 Primary helical gear 46a Helical teeth (external teeth)
47 Helical crowning gear 47a Helical crown teeth

Claims (2)

  A finish mold in which the side surfaces of the inner teeth are formed in an anti-crown shape and a primary gear in which the outer teeth are formed to have substantially the same tooth thickness over the entire length are provided, and the finish mold is taper-fitted to the clamp. In addition, the end of the shaft whose taper surface has a large diameter is brought into contact with the stopper die, the teeth of the primary gear are fitted between the teeth of the finish mold, and only the clamps are punched by the punch. The primary gear is moved in the axial direction in which the taper surface has a large diameter, the finish mold is elastically deformed to a small diameter by the clamp, and the teeth are pressed against the teeth of the primary gear. A method of manufacturing a crowning gear, wherein the teeth of the crown are formed in a crown shape.   2. The method of manufacturing a crowning gear according to claim 1, wherein each tooth of the primary gear is a helical tooth, and each tooth of the finishing mold is a helical anti-crown tooth into which each helical tooth of the primary gear is fitted.

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