CA2098662A1 - Device for forging a helical gear - Google Patents
Device for forging a helical gearInfo
- Publication number
- CA2098662A1 CA2098662A1 CA002098662A CA2098662A CA2098662A1 CA 2098662 A1 CA2098662 A1 CA 2098662A1 CA 002098662 A CA002098662 A CA 002098662A CA 2098662 A CA2098662 A CA 2098662A CA 2098662 A1 CA2098662 A1 CA 2098662A1
- Authority
- CA
- Canada
- Prior art keywords
- helical
- cavity
- truncated cone
- tooth
- punches
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000005242 forging Methods 0.000 title claims abstract description 28
- 238000001125 extrusion Methods 0.000 claims abstract description 32
- 238000003825 pressing Methods 0.000 claims description 3
- 238000000034 method Methods 0.000 description 8
- 230000015572 biosynthetic process Effects 0.000 description 5
- 230000004075 alteration Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21H—MAKING PARTICULAR METAL OBJECTS BY ROLLING, e.g. SCREWS, WHEELS, RINGS, BARRELS, BALLS
- B21H5/00—Making gear wheels, racks, spline shafts or worms
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
- B21K1/00—Making machine elements
- B21K1/28—Making machine elements wheels; discs
- B21K1/30—Making machine elements wheels; discs with gear-teeth
- B21K1/305—Making machine elements wheels; discs with gear-teeth helical
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
- B21K1/00—Making machine elements
- B21K1/28—Making machine elements wheels; discs
- B21K1/30—Making machine elements wheels; discs with gear-teeth
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Forging (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The present invention provides a device for forging a helical gear by plastic working means. The device of the invention includes a die having a cavity formed on the center thereof for receiving a work, a punch assembly disposed above the cavity and movable in a vertical direction, a plurality of helical-tooth punches mounted on a circumference of the cavity and movable in a radial direction towards a center of the cavity, and an extrusion cam disposed above the plurality of helical-tooth punches to be movable in the vertical direction and having a bottom inner surface formed as a cam face constituting a side face of a first truncated cone having predetermined first dimensions and slope. The plurality of helical-tooth punches respectively have sliding faces which are arranged to integrally form a side face of a second truncated cone and engage with the cam face of the extrusion cam. The second truncated cone has predetermine second dimensions and slope identical with or corresponding to those of the first truncated cone, and thereby perfectly fits in the first truncated cone. When the extrusion cam goes down, the plurality of helical-tooth punches are pressed in the radial direction towards the center of the cavity to form rough profiles of helical teeth around a side wall of a work set in the cavity. The punch assembly is then pressed down to finish the helical teeth roughly formed on the side wall of the work.
The present invention provides a device for forging a helical gear by plastic working means. The device of the invention includes a die having a cavity formed on the center thereof for receiving a work, a punch assembly disposed above the cavity and movable in a vertical direction, a plurality of helical-tooth punches mounted on a circumference of the cavity and movable in a radial direction towards a center of the cavity, and an extrusion cam disposed above the plurality of helical-tooth punches to be movable in the vertical direction and having a bottom inner surface formed as a cam face constituting a side face of a first truncated cone having predetermined first dimensions and slope. The plurality of helical-tooth punches respectively have sliding faces which are arranged to integrally form a side face of a second truncated cone and engage with the cam face of the extrusion cam. The second truncated cone has predetermine second dimensions and slope identical with or corresponding to those of the first truncated cone, and thereby perfectly fits in the first truncated cone. When the extrusion cam goes down, the plurality of helical-tooth punches are pressed in the radial direction towards the center of the cavity to form rough profiles of helical teeth around a side wall of a work set in the cavity. The punch assembly is then pressed down to finish the helical teeth roughly formed on the side wall of the work.
Description
209~66 ~
TITLE OF THE INVENTION
DEVICE FOR FORGING A HELICAL GEAR
BACKGROUND OF THE INVENTION
Fleld of the Invention The present invention relates to a device for forging a helical gear by plastic working means.
Description of the Related Art Development of plastic working means allows helical gears to be manufactured by forging in place of conventional machining. A typical example of forged helical gears is disclosed in Japanese Patent Laying-Open Gazette No. 64-22442, wherein helical teeth are formed on a circumference of a work while the work is pressed by a punch into a die.
In such a conventional system, since helical teeth are formed inclining to a central axis of a gear body, the die or the work is to be rotated relative to each other. The relative rotation causes insufficient precision or accuracy in formation of helical teeth as well as undesirably limits an angle of torsion or a module of the forged helical gear.
In another conventional method, a plurality of helical-tooth punches for forming helical teeth are arranged to be movable in radial direction in the same manner as straight teeth formation means as shown in Fig. 10. A plurality of straight-tooth punches 7a,7a (shown by the solid lines in Fig. 10) form straight teeth which are disposed in parallel with a central axis of a gear body. Flat sliding faces of the plurality of straight-tooth punches 7a,7a respectively correspond to and engage with flat cam faces of a plurality of extrusion cams 8a,8a (shown by the one-dot broken lines in 2~9~6~
Fig. 10) which are movable along the central axis. A
plurality of helical-tooth punches 7,7 (shown by the doted lines in Fig. 10) form helical teeth which are inclined to the central axis of the gear body. Each flat sliding face of the helical-tooth punches 7,7 does not preferably correspond to or engage with each flat cam face of the extrusion cams 8a,8a due to interference of an ad~acent extrusion cam 8a.
Of course, the sliding faces of the helical-tooth punche~ can theoretically be arranged in parallel with the central axis of the gear by distorting the helical-tooth punches by respective required angles. This method is, however, not practical because of insufficient pressure resistance of the forged helical teeth. Namely, there is no practical method of mass producing hellcal gears with high precision by plastic working means.
SUMMARY OF THE INVENTION
- One ob~ect of the invention is to provide a novel device for forging a helical gear by plastic working means.
Another ob~ect of the invention is to provide a helical gear forglng devlce including a die which is free from a rotation relative to a work.
The above and other related ob~ects are realized by a device for forging a helical gear. The device includes: a die having a cylindrical cavity formed on the center thereof for receiving a work; a punch assembly disposed above the cavity and movable in a vertical direction; and a plurality of helical~tooth punches for forming rough profiles of helical teeth around the work set in the cavity. The plurality of helical-tooth punches are mounted on a 2n~s~ ~
circumference of the cylindrical cavity and movable in a radial direction towards a center of the cavity. The device further lncludes an extrusion cam disposed above the plurality of helical-tooth punches and mo~able in the vertical direction.
The extrusion cam has a bottom inner surface formed as a cam face constituting a side face of a first truncated cone having predetermined first dimensions and a slope. The plurality of helical-tooth punches respectively have sliding faces which are arranged to integrally form a side face of a second truncated cone and engage with the cam face of the extrusion cam. The second truncated cone has predetermine second dimensions and a slope identical with or corresponding to those of the first truncated cone, and thereby perfectly fits in the first truncated cone.
When the extrusion cam goes down in the vertical direction, the cam face of the extrusion cam fittingly engages with and presses against the sliding faces of the hellcal-tooth punches to move the helical-tooth punches in the radial direction towards the center of the cavity to form rough profiles of helical teeth around a side wall of a work set in the cavity. The punch assembly is then pressed down to finish the helical teeth roughly formed on the side wall of the work.
The above structure of the invention allows the truncated cone-shaped cam face of the e~trusion cam to effectively press the sliding faces of the helical-tooth punches in the radial direction towards the center of the cavity. Each helical-tooth punch is partly overlapped ~ith ad~acent helical-tooth punches. Since the second truncated cone 20~3~
formed by integrating the sliding faces of the helical-tooth punches perfectly fits in the first truncated cone of the cam face of the extrusion cam, the cam face sufficiently presses all the partly overlapped helical-tooth punches in the radial direction to form rough profiles of helical teeth around a work.
These and other ob~ects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiment with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 shows a device for forging a helical gear embodying the invention;
Fig. 2 shows a relationship between a cam face of an extrusion cam and sliding faces of a plurality of helical-tooth punches;
Fig. 3 shows a process for forging a helical gear with the helical gear forging device of Fig. 1;
Fig. 4 shows a process for forging a helical gear with the helical gear forging device of Fig. 1;
Fig. 5 shows a first step for forming helical teeth on a gear;
Fig. 6 shows a second step for forming helical teeth on a gear;
Fig. 7 shows a third step for forming helical teeth on a gear;
Fig. 8 shows a process for forging a helical gear with the helical gear forging device of Fig. 1;
Fig. 9 shows a process for forging a helical gear with the 2~9~6~' helical gear forging device of Fig. 1; and Fig. 10 shows a relationship between cam faces of a plurality of extrusion cams and sliding faces of a plurality of helical-tooth punches in a prior art structure.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A device for forging a helical gear embodying the invention is described in detail according to the drawings.
As shown in Fig. 1, a helical gear forming device of the embodiment includes a die 1, a punch assembly 3, and an e~ector 5. The die 1 includes a disk-shaped cavity 2 formed on its center. The punch assembly 3 is located immediately above the die 1 to be movable in a vertical direction between an upper position and a lower position for pressing a work 4 down into the cavity 2. The work 4 has a larger-diametral element and a smaller-diametral element. The ejector 5, which is also movable in the vertical direction between an upper position and a lower position, goes through a central portion of the cavity 2 to press the work 4 up.
The cavity 2 includes a smaller-diametral portion having a straight teeth forging element 6 arranged on a circumference thereof for forming straight teeth on the smaller-diametral element of the work 4, and a larger-diametral portion having a plurality of helical-tooth punches 7,7 mounted on a circumference thereof for forming rough profiles of helical teeth on the larger-diametral element of the work 4. The helical-tooth punches 7,7 are supported on the larger-diametral portion of the cavity 2 to be freely movable in a radial direction between a first radial position and a second radial position. The larger-diametral portion of the cavity 2 also has a helical teeth forging element consisting of a 2~9~
plurallty of grooves 9,9 for forming helical teeth around the larger-diametral element of the work 4, in combination with the plurality of helical-tooth punches 7,7.
A cylindrical extrusion cam 8, which is movable in the vertical direction between a first vertical position and a second vertical position, is further disposed above the plurality of helical-tooth punches 7,7. The extrusion cam 8 goes down to the second vertical position to press the helical-tooth punches 7,7 towards the center of the cavity 2 to the second radial position. Each helical-tooth punch 7 is provided with a spring 12 for returning the helical-tooth punch 7, which is pressed to the second radial position by the extrusion cam 8, to the first radial position.
~ ach helical-tooth punch 7, in combination with an ad~acent helical-tooth groove 9 of the ca~ity 2, roughly forms a helical-tooth profile on the larger-diametral element of the work 4 when being pressed in the radial direction by the extrusion cam 8. The cylindrical extrusion cam 8 concentrically arranged with the punch assembly 3 has an inner bottom surface formed as a cam face constituting a side face of a first truncated cone having predetermined first dimensions and slope. The helical-tooth punches 7,7 respectively have sliding faces which are arranged to integrally form a side face of a second truncated cone and engage with the cam face of the extrusion cam R as clearly seen in Fig. 2. That is, the sliding face of each helical-tooth punch 7 is a curved surface constituting part of the second truncated cone. The second truncated cone has predetermine second dimensions and a slope identical with or ```` 2~9~
corresponding to those of the first truncated cone, and thereby perfectly fits in the first truncated cone. This structure allows any part of the circular cam face of the cylindrical extrusion cam 8 to sufficiently press the helical-tooth punches 7,7 towards the center of the cavity 2.
A process for manufacturing a helical gear with the helical gear forging device thus constructed is described according to the drawings.
The work 4 is placed on an upper surface of the e~ector 5 lifted up to its upper position, and then set into the cavity 2 by lifting down the e~ector 5 to its lo~er position ~see Fig. 3). In a subsequent step, the extrusion cam 8 is lowered to the second vertical position to press the plurality of helical-tooth punches 7,7 to~ards the center of the cavity to the second radial position as clearly seen in Fig. 4. While the plurality of helical-tooth punches 7,7 are pressed in the radial direction by the extrusion cam 8, each helical-tooth punch 7, in combination with an ad~acent helical-tooth groove 9, roughly forms a helical-tooth profile on the larger-diametral element of the work 4 set in the cavity 2 (see Figs. 5 and 6).
The punch assembly 3 is then lifted do~n to its lower position to press the work 4 down as sho~n in Fig. 8. The work 4 is radially expanded by the pressing force of the punch asse~bly 3 to fill the straight teeth forging element 6 and the plurality of helical-tooth grooves 9,9. This results in forming straight teeth 10 around the s~aller-diametral portion of the work 4 and finishing helical teeth 11 around the larger-diametral portion of the wor~ $ (see Fig. 7).
After formation of the straight teeth 10 and the helical 2 a ~
:
teeth 11 is completed, the plurality of helical-tooth punches 7,7 are returned to the first radial position by means of the ' plurality of springs 12,12 while the punch assembly 3 is lifted up to its upper position. At a last step, the ejector 5 is lifted up to its upper position to press the work 4 having the straight teeth 10 and the helical teeth 11 out of the cavity 2 as shown in Fig. 9. A through hole for a shaft may be formed in the work 4 after completion of the above forging process, or alternatively formed simultaneously with formation of gear teeth on a ring-shaped ~ork using a mandrel.
As described above in detail, the helical gear forging device of the invention allows formation of helical teeth with high precision without rotating a work or a die relative to each other. The integrally formed extrusion cam of the device has sufficient strength and preferable durability and is applicable to any teeth number, module, and tooth profile.
Since there may be many modifications, alterations, and changes without departing from the scope or spirit of essential characteristics of the invention, it is clearly understood that the above embodiment is only illustrative and not restrictive in any sense. For example, the plurality of helical-tooth punches and the vertically movable punch assembly may be operated simultaneously to form helical teeth on a side wall of a work. Although the smaller-diametral portion of the cavity has the straight teeth forging element in the above embodiment, it may be omitted to form a flat boss on the smaller-diametral element of the work. In another example, the d~e may have a one-step cavity insteaA
2~6~ `~
of the two-step cavity of the embodiment.
TITLE OF THE INVENTION
DEVICE FOR FORGING A HELICAL GEAR
BACKGROUND OF THE INVENTION
Fleld of the Invention The present invention relates to a device for forging a helical gear by plastic working means.
Description of the Related Art Development of plastic working means allows helical gears to be manufactured by forging in place of conventional machining. A typical example of forged helical gears is disclosed in Japanese Patent Laying-Open Gazette No. 64-22442, wherein helical teeth are formed on a circumference of a work while the work is pressed by a punch into a die.
In such a conventional system, since helical teeth are formed inclining to a central axis of a gear body, the die or the work is to be rotated relative to each other. The relative rotation causes insufficient precision or accuracy in formation of helical teeth as well as undesirably limits an angle of torsion or a module of the forged helical gear.
In another conventional method, a plurality of helical-tooth punches for forming helical teeth are arranged to be movable in radial direction in the same manner as straight teeth formation means as shown in Fig. 10. A plurality of straight-tooth punches 7a,7a (shown by the solid lines in Fig. 10) form straight teeth which are disposed in parallel with a central axis of a gear body. Flat sliding faces of the plurality of straight-tooth punches 7a,7a respectively correspond to and engage with flat cam faces of a plurality of extrusion cams 8a,8a (shown by the one-dot broken lines in 2~9~6~
Fig. 10) which are movable along the central axis. A
plurality of helical-tooth punches 7,7 (shown by the doted lines in Fig. 10) form helical teeth which are inclined to the central axis of the gear body. Each flat sliding face of the helical-tooth punches 7,7 does not preferably correspond to or engage with each flat cam face of the extrusion cams 8a,8a due to interference of an ad~acent extrusion cam 8a.
Of course, the sliding faces of the helical-tooth punche~ can theoretically be arranged in parallel with the central axis of the gear by distorting the helical-tooth punches by respective required angles. This method is, however, not practical because of insufficient pressure resistance of the forged helical teeth. Namely, there is no practical method of mass producing hellcal gears with high precision by plastic working means.
SUMMARY OF THE INVENTION
- One ob~ect of the invention is to provide a novel device for forging a helical gear by plastic working means.
Another ob~ect of the invention is to provide a helical gear forglng devlce including a die which is free from a rotation relative to a work.
The above and other related ob~ects are realized by a device for forging a helical gear. The device includes: a die having a cylindrical cavity formed on the center thereof for receiving a work; a punch assembly disposed above the cavity and movable in a vertical direction; and a plurality of helical~tooth punches for forming rough profiles of helical teeth around the work set in the cavity. The plurality of helical-tooth punches are mounted on a 2n~s~ ~
circumference of the cylindrical cavity and movable in a radial direction towards a center of the cavity. The device further lncludes an extrusion cam disposed above the plurality of helical-tooth punches and mo~able in the vertical direction.
The extrusion cam has a bottom inner surface formed as a cam face constituting a side face of a first truncated cone having predetermined first dimensions and a slope. The plurality of helical-tooth punches respectively have sliding faces which are arranged to integrally form a side face of a second truncated cone and engage with the cam face of the extrusion cam. The second truncated cone has predetermine second dimensions and a slope identical with or corresponding to those of the first truncated cone, and thereby perfectly fits in the first truncated cone.
When the extrusion cam goes down in the vertical direction, the cam face of the extrusion cam fittingly engages with and presses against the sliding faces of the hellcal-tooth punches to move the helical-tooth punches in the radial direction towards the center of the cavity to form rough profiles of helical teeth around a side wall of a work set in the cavity. The punch assembly is then pressed down to finish the helical teeth roughly formed on the side wall of the work.
The above structure of the invention allows the truncated cone-shaped cam face of the e~trusion cam to effectively press the sliding faces of the helical-tooth punches in the radial direction towards the center of the cavity. Each helical-tooth punch is partly overlapped ~ith ad~acent helical-tooth punches. Since the second truncated cone 20~3~
formed by integrating the sliding faces of the helical-tooth punches perfectly fits in the first truncated cone of the cam face of the extrusion cam, the cam face sufficiently presses all the partly overlapped helical-tooth punches in the radial direction to form rough profiles of helical teeth around a work.
These and other ob~ects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiment with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 shows a device for forging a helical gear embodying the invention;
Fig. 2 shows a relationship between a cam face of an extrusion cam and sliding faces of a plurality of helical-tooth punches;
Fig. 3 shows a process for forging a helical gear with the helical gear forging device of Fig. 1;
Fig. 4 shows a process for forging a helical gear with the helical gear forging device of Fig. 1;
Fig. 5 shows a first step for forming helical teeth on a gear;
Fig. 6 shows a second step for forming helical teeth on a gear;
Fig. 7 shows a third step for forming helical teeth on a gear;
Fig. 8 shows a process for forging a helical gear with the helical gear forging device of Fig. 1;
Fig. 9 shows a process for forging a helical gear with the 2~9~6~' helical gear forging device of Fig. 1; and Fig. 10 shows a relationship between cam faces of a plurality of extrusion cams and sliding faces of a plurality of helical-tooth punches in a prior art structure.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A device for forging a helical gear embodying the invention is described in detail according to the drawings.
As shown in Fig. 1, a helical gear forming device of the embodiment includes a die 1, a punch assembly 3, and an e~ector 5. The die 1 includes a disk-shaped cavity 2 formed on its center. The punch assembly 3 is located immediately above the die 1 to be movable in a vertical direction between an upper position and a lower position for pressing a work 4 down into the cavity 2. The work 4 has a larger-diametral element and a smaller-diametral element. The ejector 5, which is also movable in the vertical direction between an upper position and a lower position, goes through a central portion of the cavity 2 to press the work 4 up.
The cavity 2 includes a smaller-diametral portion having a straight teeth forging element 6 arranged on a circumference thereof for forming straight teeth on the smaller-diametral element of the work 4, and a larger-diametral portion having a plurality of helical-tooth punches 7,7 mounted on a circumference thereof for forming rough profiles of helical teeth on the larger-diametral element of the work 4. The helical-tooth punches 7,7 are supported on the larger-diametral portion of the cavity 2 to be freely movable in a radial direction between a first radial position and a second radial position. The larger-diametral portion of the cavity 2 also has a helical teeth forging element consisting of a 2~9~
plurallty of grooves 9,9 for forming helical teeth around the larger-diametral element of the work 4, in combination with the plurality of helical-tooth punches 7,7.
A cylindrical extrusion cam 8, which is movable in the vertical direction between a first vertical position and a second vertical position, is further disposed above the plurality of helical-tooth punches 7,7. The extrusion cam 8 goes down to the second vertical position to press the helical-tooth punches 7,7 towards the center of the cavity 2 to the second radial position. Each helical-tooth punch 7 is provided with a spring 12 for returning the helical-tooth punch 7, which is pressed to the second radial position by the extrusion cam 8, to the first radial position.
~ ach helical-tooth punch 7, in combination with an ad~acent helical-tooth groove 9 of the ca~ity 2, roughly forms a helical-tooth profile on the larger-diametral element of the work 4 when being pressed in the radial direction by the extrusion cam 8. The cylindrical extrusion cam 8 concentrically arranged with the punch assembly 3 has an inner bottom surface formed as a cam face constituting a side face of a first truncated cone having predetermined first dimensions and slope. The helical-tooth punches 7,7 respectively have sliding faces which are arranged to integrally form a side face of a second truncated cone and engage with the cam face of the extrusion cam R as clearly seen in Fig. 2. That is, the sliding face of each helical-tooth punch 7 is a curved surface constituting part of the second truncated cone. The second truncated cone has predetermine second dimensions and a slope identical with or ```` 2~9~
corresponding to those of the first truncated cone, and thereby perfectly fits in the first truncated cone. This structure allows any part of the circular cam face of the cylindrical extrusion cam 8 to sufficiently press the helical-tooth punches 7,7 towards the center of the cavity 2.
A process for manufacturing a helical gear with the helical gear forging device thus constructed is described according to the drawings.
The work 4 is placed on an upper surface of the e~ector 5 lifted up to its upper position, and then set into the cavity 2 by lifting down the e~ector 5 to its lo~er position ~see Fig. 3). In a subsequent step, the extrusion cam 8 is lowered to the second vertical position to press the plurality of helical-tooth punches 7,7 to~ards the center of the cavity to the second radial position as clearly seen in Fig. 4. While the plurality of helical-tooth punches 7,7 are pressed in the radial direction by the extrusion cam 8, each helical-tooth punch 7, in combination with an ad~acent helical-tooth groove 9, roughly forms a helical-tooth profile on the larger-diametral element of the work 4 set in the cavity 2 (see Figs. 5 and 6).
The punch assembly 3 is then lifted do~n to its lower position to press the work 4 down as sho~n in Fig. 8. The work 4 is radially expanded by the pressing force of the punch asse~bly 3 to fill the straight teeth forging element 6 and the plurality of helical-tooth grooves 9,9. This results in forming straight teeth 10 around the s~aller-diametral portion of the work 4 and finishing helical teeth 11 around the larger-diametral portion of the wor~ $ (see Fig. 7).
After formation of the straight teeth 10 and the helical 2 a ~
:
teeth 11 is completed, the plurality of helical-tooth punches 7,7 are returned to the first radial position by means of the ' plurality of springs 12,12 while the punch assembly 3 is lifted up to its upper position. At a last step, the ejector 5 is lifted up to its upper position to press the work 4 having the straight teeth 10 and the helical teeth 11 out of the cavity 2 as shown in Fig. 9. A through hole for a shaft may be formed in the work 4 after completion of the above forging process, or alternatively formed simultaneously with formation of gear teeth on a ring-shaped ~ork using a mandrel.
As described above in detail, the helical gear forging device of the invention allows formation of helical teeth with high precision without rotating a work or a die relative to each other. The integrally formed extrusion cam of the device has sufficient strength and preferable durability and is applicable to any teeth number, module, and tooth profile.
Since there may be many modifications, alterations, and changes without departing from the scope or spirit of essential characteristics of the invention, it is clearly understood that the above embodiment is only illustrative and not restrictive in any sense. For example, the plurality of helical-tooth punches and the vertically movable punch assembly may be operated simultaneously to form helical teeth on a side wall of a work. Although the smaller-diametral portion of the cavity has the straight teeth forging element in the above embodiment, it may be omitted to form a flat boss on the smaller-diametral element of the work. In another example, the d~e may have a one-step cavity insteaA
2~6~ `~
of the two-step cavity of the embodiment.
Claims (9)
1. A device for forging a helical gear, said device comprising a die having a cylindrical cavity formed on the center thereof for receiving a work, a plurality of helical-tooth punches for roughly forming helical teeth around said work set in said cavity, said plurality of helical-tooth punches being mounted on a circumference of said cylindrical cavity and movable in a radial direction towards a center of said cavity, a punch assembly disposed above said cavity and movable in a vertical direction for finishing helical teeth roughly formed by said plurality of helical-tooth punches, and an extrusion cam disposed above said plurality of helical-tooth punches and movable in the vertical direction for pressing said plurality of helical-tooth punches in the radial direction towards the center of said cavity, wherein improvement being characterized by said extrusion cam having a bottom inner surface formed as a cam face constituting a side face of a first truncated cone, and said plurality of helical-tooth punches respectively having sliding faces which are arranged to integrally form a side face of a second truncated cone and engage with said cam face of said extrusion cam.
2. A device in accordance with claim 1, wherein said first truncated cone has predetermined first dimensions and slope whereas said second truncated cone has predetermined second dimensions and slope identical with or corresponding to those of said first truncated cone, so that said second truncated cone perfectly fits in said first truncated cone.
3. A device in accordance with claim 2, wherein said cavity of said die has a larger-diametral portion and a smaller-diametral portion, and said plurality of helical-tooth punches are mounted on a circumference of said larger-diametral portion.
4. A device in accordance with claim 3, wherein said smaller-diametral portion of said cavity further comprises a straight teeth forging element arranged on a circumference thereof.
5. A device for forging a helical gear, said device comprising a die having a cylindrical cavity formed on the center thereof for receiving a work, ejection means disposed along a vertical axis of said die to be movable in a vertical direction between an up-position and a down-position and pass through a central portion of said cylindrical cavity, said ejection means holding said work and going up to said up-position to press said work out of said cavity, a plurality of helical-tooth punches for roughly forming helical teeth around said work set in said cavity, said plurality of helical-tooth punches being mounted on a circumference of said cylindrical cavity and movable in a radial direction between a first radial position and a second radial position, a plurality of helical-tooth grooves formed around said cavity for forming helical teeth around said work, in combination with said plurality of helical-tooth punches, a punch assembly disposed above said cavity and movable in a vertical direction between an upper position and a lower position, said punch assembly going down to said lower position to finish helical teeth roughly formed by said plurality of helical-tooth punches, and an extrusion cam disposed above said plurality of helical-tooth punches and movable in the vertical direction between a first vertical direction and a second vertical direction, said extrusion cam going down to said second vertical direction to press said plurality of helical-tooth punches in the radial direction to said second radial position, wherein improvement being characterized by said extrusion cam having a bottom inner surface formed as a cam face constituting a side face of a first truncated cone, and said plurality of helical-tooth punches respectively having sliding faces which are arranged to integrally form a side face of a second truncated cone and engage with said cam face of said extrusion cam.
6. A device in accordance with claim 5, wherein said first truncated cone has predetermined first dimensions and slope whereas said second truncated cone has predetermined second dimensions and slope identical with or corresponding to those of said first truncated cone, so that said second truncated cone perfectly fits in said first truncated cone.
7. A device in accordance with claim 6, wherein each of said plurality of helical-tooth punches comprises a spring for returning each said helical-tooth punch, which is pressed to said second radial position by said extrusion cam, to said first radial position.
8. A device in accordance with claim 6, wherein said cavity of said die has a larger-diametral portion and a smaller-diametral portion, and said plurality of helical-tooth punches are mounted on a circumference of said larger-diametral portion.
9. A device in accordance with claim 8, wherein said smaller-diametral portion of said cavity further comprises a straight teeth forging element arranged on a circumference thereof.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4-049,165 | 1992-06-18 | ||
| JP1992049165U JP2577170Y2 (en) | 1992-06-18 | 1992-06-18 | Helical gear forming equipment |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2098662A1 true CA2098662A1 (en) | 1993-12-19 |
Family
ID=12823474
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002098662A Abandoned CA2098662A1 (en) | 1992-06-18 | 1993-06-17 | Device for forging a helical gear |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0584907A3 (en) |
| JP (1) | JP2577170Y2 (en) |
| KR (1) | KR940000539U (en) |
| CA (1) | CA2098662A1 (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE59810933D1 (en) | 1997-12-07 | 2004-04-08 | Feintool Internat Holding Ag L | METHOD FOR MACHINING A WORKPIECE AND RELATED DEVICE |
| US5996229A (en) * | 1998-09-25 | 1999-12-07 | Yang; Tsung-Hsun | Method and mold die for forming a spiral bevel gear from metal powders |
| AT505947B1 (en) * | 2007-11-14 | 2016-04-15 | Miba Sinter Austria Gmbh | COMPRESSION TOOL |
| CN103260789B (en) * | 2010-11-12 | 2016-07-13 | Pmg阿斯图里亚斯粉末金属公司 | The instrument of processing work |
| US9427790B2 (en) | 2010-11-12 | 2016-08-30 | Pmg Asturias Powder Metal S.A.U. | Method for forming a workpiece |
| CN102319759B (en) * | 2011-07-20 | 2014-01-15 | 重庆创精温锻成型有限公司 | Cold extruding method for tooth form opening angle on gear ring of automobile gear-shifting combining gear |
| DE102013002043A1 (en) * | 2013-02-07 | 2014-08-07 | Sona Blw Präzisionsschmiede Gmbh | Calibration die and method of making a gear ratchet with running teeth |
| CN111531098A (en) * | 2020-04-28 | 2020-08-14 | 思进智能成形装备股份有限公司 | Cold heading forming process of automobile safety belt torsion shaft |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3263474A (en) * | 1962-12-14 | 1966-08-02 | Ford Motor Co | Method and apparatus for forming splines |
| GB1096846A (en) * | 1965-03-25 | 1967-12-29 | Zd Gomselmash | Method of and apparatus for manufacturing profiled articles by pressing |
| US3803896A (en) * | 1972-05-19 | 1974-04-16 | Automobilove Zavody Np | Method and apparatus for forming locking surfaces on gear rings |
| JP2706927B2 (en) * | 1989-01-27 | 1998-01-28 | 三菱自動車工業株式会社 | Processing device by cam type |
-
1992
- 1992-06-18 JP JP1992049165U patent/JP2577170Y2/en not_active Expired - Fee Related
-
1993
- 1993-06-08 KR KR2019930009890U patent/KR940000539U/en not_active Application Discontinuation
- 1993-06-15 EP EP93304657A patent/EP0584907A3/en not_active Withdrawn
- 1993-06-17 CA CA002098662A patent/CA2098662A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| JPH06546U (en) | 1994-01-11 |
| EP0584907A2 (en) | 1994-03-02 |
| JP2577170Y2 (en) | 1998-07-23 |
| EP0584907A3 (en) | 1995-09-06 |
| KR940000539U (en) | 1994-01-03 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |