JP4357079B2 - Gear for shifting and manufacturing apparatus therefor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention mainly relates to a speed change gear having a gear change gear and a clutch spline gear used for a transmission of a transmission, and a manufacturing apparatus thereof.
[0002]
[Prior art]
Conventionally, a transmission gear having a gear teeth and a clutch spline gear used in a transmission of a transmission is:
(1) A method of forming gears for shifting and spline teeth by machining such as hobbing on gear teeth for shifting and clutch spline teeth formed integrally by hot forging.
(2) Clutch spline teeth having shift gear teeth formed by machining such as hobbing on the shift gear teeth formed by hot forging, and the spline teeth formed by cold forging. Method of integrating the parts with spline connection or electron beam welding
(3) The gear teeth for shifting and the clutch spline teeth formed integrally by hot forging, the gear teeth for shifting by machining such as hobbing, and the spline teeth by hot forging and cold forging, respectively. How to form
And so on.
[0003]
By the way, in any of the above methods (1) to (3), the gears for shifting are formed by machining such as hobbing on the gears for shifting, so that the metal flow of the gears for shifting is cut. However, there is a problem that the strength of the gear is lowered and an increase in manufacturing cost due to machining cannot be avoided.
[0004]
[Problems to be solved by the invention]
In order to cope with this problem, it is conceivable to adopt a method in which gears for shifting are formed on the gear teeth for shifting by, for example, cold forging using a press, but a clutch spline in which reverse tapered spline teeth are formed. It has been difficult to ensure concentricity between the tooth portion and the speed change tooth portion on which the speed change teeth are formed, and it has not been possible to manufacture a highly accurate speed change gear.
[0005]
Further, as shown in FIG. 11, the speed change gear W that is currently widely used in a transmission of a transmission has a speed change gear portion Pa and a clutch spline tooth portion Pb, and shifts to the speed change gear portion Pa. Helical teeth Ga as dental teeth are formed, and reverse tapered spline teeth Gb each having a chamfer Cb at the tip are formed on the clutch spline tooth portion Pb.
As shown in FIG. 10C, the helical teeth Ga formed on the gear teeth Pa for shifting generally have a right or left helix angle α of 15 ° to 35 °, and gear shifting. In order to reduce gear noise when the gear W is rotated at high speed, it is formed with high teeth.
[0006]
For this reason, for example, when trying to mold the helical tooth Ga by cold forging by press, the tooth surface Fa of the helical tooth Ga supports most of the molding pressure, the helical tooth Ga bends, and the helical tooth A gap is generated in the Ga tooth surface Fb, and the material flows through the gap.
As a result, the helical tooth Ga is not only formed with a different twist angle αa of the tooth surface Fa and a twist angle αb of the tooth surface Fb, making it difficult to manufacture a highly accurate gear, This tendency becomes more prominent as the torsion angle α becomes larger. Therefore, helical teeth having a torsion angle α of 30 ° or more could not be formed by cold forging using a press.
[0007]
In addition, although the gear W for transmission is formed by forming a helical tooth Ga (see FIG. 10D) having a crowning Ca on the tooth surface on the gear tooth Pa for transmission, cold forging by pressing is used. In some cases, the crowning could not be formed.
[0008]
In view of the problems of the conventional transmission gear and the manufacturing method thereof, the present invention provides a transmission tooth portion and a clutch spline tooth portion including a transmission tooth and a reverse-tapered spline tooth having a chamfer at the tip. An object of the present invention is to provide a speed change gear and a manufacturing apparatus for the speed change gear which are formed by forging with high accuracy.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the speed change gear of the present invention includes: While having a shaft hole in the center, The gear teeth for shifting and the clutch spline teeth formed integrally by forging , In the axial direction And having a reverse-tapered spline tooth having a chamfer at the tip of the clutch spline tooth part, the speed change tooth of the speed change tooth part includes the reverse taper spline tooth. Clutch spline teeth formed Outer peripheral surface Based on The shaft hole with the inner peripheral surface turned is held by chuck means. Then, the reverse tooth taper formed on the clutch spline tooth portion is formed by forging with a rolling die on the gear tooth for shifting, and is formed on the clutch spline tooth portion from the diameter of the base circle of the gear teeth for shifting formed on the gear tooth for shifting. The diameter of the tip circle of the spline teeth is large, and the gap between the gear teeth for shifting and the clutch spline teeth is 2 mm or less.
[0010]
The gears for transmission targeted by the present invention include those having helical teeth and spur teeth.
[0011]
Further, the gears for transmission targeted by the present invention include those having a crowning on the tooth surface.
[0012]
Further, in the gear for shifting which is an object of the present invention, a die in which reverse tapered spline teeth are arranged radially with respect to the gear axis line between the spline teeth parallel to the gear axis line formed by forging is provided. It is formed into a shape that conforms to the shape of the tip of the die by pressing toward the center of the gear in a direction perpendicular to the center of the die.
[0013]
The transmission gear manufacturing apparatus of the present invention relates to an apparatus for manufacturing the above-described transmission gear of the present invention, It has a shaft hole in the center and a gear tooth for shifting and a clutch spline tooth portion integrally formed by forging on the outer peripheral surface in order in the axial direction. The clutch spline tooth portion has a chamfer at the tip. In an apparatus for manufacturing a transmission gear for forming a reverse-tapered spline tooth having forging by forging, Reverse spline teeth By forging The clutch spline tooth portion is formed at the center of the work gear on which the formed clutch spline tooth portion is formed. Outer peripheral surface Based on Turning inner surface A chuck means for holding the shaft hole, a tail stock for rotating the gear to be processed around the shaft hole as a central axis, and a synchronization that is arranged in the tail stock and rotates together with the tail stock. A gear and a rolling spindle which is arranged in parallel with the tailstock and meshes with the synchronous gear and a rolling spindle provided with a rolling die; By rotating the tailstock, via the chuck means, A rotating tooth that rotates in synchronization with the workpiece gear via the synchronous gear and the driven gear while rotating about the shaft hole as a central axis is preliminarily formed in the gear teeth for transmission of the workpiece gear. The present invention is characterized in that finish molding of the gears for transmission is performed.
[0014]
In this case, the chuck means is composed of a collet chuck and a male cone which is inserted into the collet chuck and expands the diameter of the collet chuck so as to hold a shaft hole drilled in the center of the gear to be processed. Can do.
[0015]
In addition, the rolling die is used as the gear teeth for gear change. By forging It can comprise so that the finish shaping of the helical tooth which carried out rough formation beforehand may be performed.
[0016]
In addition, the rolling dies are attached to the gear teeth for gear change. By forging It is possible to configure so that the crowning is formed on the tooth surface of the speed change tooth which is roughly formed in advance.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a transmission gear and a manufacturing apparatus thereof according to the present invention will be described below based on the drawings.
[0018]
First, a method for forming a transmission gear according to the present invention will be described with reference to FIG. 1 in the case of forming a transmission gear W having the form shown in FIGS.
[0019]
First, a material suitable for the transmission gear W to be manufactured is cut into a predetermined size with a billet shear or a saw (FIGS. 1 (1) and (2)), and the material W0 is hot or warm forged. It is heated to a temperature suitable for the above (FIG. 1 (3)).
[0020]
In this case, a steel material suitable for the transmission gear W, for example, SC steel, SCM steel, SNC steel, SNCM steel, SCR steel, or the like can be used as the material.
The heating temperature can be determined according to whether it is hot or warm forging, the material quality, shape, size, etc., and is heated to 1150 ° C. to 1200 ° C., for example.
[0021]
After heating, the material W0 is subjected to a plurality of hot or warm forging processes to integrally form the gear teeth Pa and the clutch spline teeth Pb, and the gear teeth Ra for gear shift Pa. Spline teeth Rb parallel to the gear axis line are formed on the clutch spline teeth portion Pa in the intermediate product W4 which is roughly formed.
This hot forging process is not particularly limited, but usually, an upsetting process (FIG. 1 (4)), a blocker process (FIG. 1 (5)), a finisher process (FIG. 1 (6)) and piercing. It consists of four steps (FIG. 1 (7)).
Of these, the upsetting process (FIG. 1 (4)) is a process of forming the material W0 into a shape that is easy to forge. The material W1 that has undergone this process is converted into a blocker process (FIG. 1 (5)) and a finisher process (FIG. 1). 1 (6) (details will be described later), the entire shape is adjusted to a required shape, and the required teeth are roughly formed on the gear teeth Pa and the clutch spline teeth Pb.
The blocker process and the finisher process can be configured by a plurality of processes depending on the material of the material W1, the shape, size, etc. of the intermediate product W1 to be molded.
Then, an intermediate product W4 having a shaft hole H formed at the center of the intermediate product W3 is obtained by the piercing process (FIG. 1 (7)). The diameter of the shaft hole H is formed to be slightly smaller than the final finished dimension.
[0022]
In the heat treatment step (FIG. 1 (8)), if necessary, heat treatment such as normalization is performed on the intermediate product W4 having the required teeth roughly formed on the gear teeth Pa and the clutch spline teeth Pb. In the shot blasting process (FIG. 1 (9)), the scale adhering to the surface of the intermediate product W4 is removed, and in the lubricating process (FIG. 1 (10)), the next cold forging process is smoothly performed. Therefore, necessary lubrication treatment such as bonderite / bonderube treatment and treatment with a molybdenum disulfide-based lubricant is performed.
[0023]
For the intermediate product W4 that has undergone the lubrication process (FIG. 1 (10)), in the cold coining process (FIG. 1 (11)), the spline teeth Rb parallel to the gear axis roughly formed on the clutch spline teeth Pb After the finish molding, the spline teeth Sb parallel to the gear axis formed on the clutch spline tooth portion Pb are formed on the intermediate product W5 in the spline tooth forming step (FIG. 1 (12), details will be described later). Then, the spline teeth Gb having a reverse taper shape are formed.
[0024]
Clutch spline formed with reverse-tapered spline teeth Gb molded to the final finished dimensions in the machining step (FIG. 1 (13)) for the intermediate product W6 that has undergone the spline tooth forming step (FIG. 1 (12)) With reference to the outer peripheral surface of the tooth portion Pb, the end surface of the intermediate product W6 (to make a perpendicularity to the outer peripheral surface of the clutch spline tooth portion Pb), the inner peripheral surface of the shaft hole H (the outer peripheral surface of the clutch spline tooth portion Pb) Turning other parts to make concentricity.
[0025]
The intermediate product W7 that has undergone the machining process (FIG. 1 (13)) is rotated about the shaft hole H as the central axis in a gear forming step (FIG. 1 (14), details will be described later) by flow forming. On the other hand, the speed change tooth Ra roughly formed on the speed change tooth portion Pa is finished into the speed change tooth Ga.
At this time, the crowning Ca can be formed on the tooth surface of the gear teeth Ra as needed.
[0026]
In the machining step (FIG. 1 (15)), the outer diameter, end face, and other parts of the shifting tooth portion Pa are turned in the machining process (FIG. 1 (15)) for the intermediate product W8 that has undergone the gear formation step (FIG. 1 (14)). Then, in the heat treatment step (FIG. 1 (16)), the required heat treatment such as carburizing and quenching and tempering is performed, and after the polishing treatment step (FIG. 1 (17)), the final product transmission gear W Can be obtained.
[0027]
Next, the finisher process of FIG. 1 (6) will be described in detail.
In the finisher process, the intermediate part W2 in which the overall shape is adjusted to the required shape by the blocker process (FIG. 1 (5)) of the hot or warm forging process, the gear teeth for shifting Pa, the clutch spline tooth part Pb, Are integrally formed, and the gear teeth Ra for transmission are roughly formed on the tooth portions Pa for transmission, and the spline teeth Rb parallel to the gear axis line are roughly formed on the clutch spline teeth portion Pb.
[0028]
An example of a rough tooth forming apparatus for carrying out this finisher process is shown in FIG.
This rough tooth forming device 3 is for simultaneously simultaneously forming a helical tooth Ra as a speed change tooth on the speed change tooth portion Pa and a spline tooth Rb parallel to the gear axis line on the clutch spline tooth portion Pb. The structure will be described below.
[0029]
A die mounting base 31 is mounted on the base 30, and a gear die 32 is mounted on the die mounting base 31.
The gear die 32 is formed in a cylindrical shape and has molding teeth 32a corresponding to the helical teeth Ra formed on the gear teeth Pa for the intermediate product W2 on the inner peripheral surface thereof.
Further, in the gear die 32, an upper punch 33U and a lower punch 33D that sandwich and press the intermediate product W2 from above and below to cause plastic deformation are inserted from above and below, respectively. In this case, when the forming teeth 32a of the gear die 32 and the driven teeth 33a formed on the outer peripheral surface of the lower punch 33D are engaged with each other and the lower punch 33D moves in the gear die 32, the lower punch 33D is matched to the movement amount. Is configured to rotate.
The upper and lower punches 33U and 33D are formed in a shape that can be formed into the intermediate product W3 by causing plastic deformation of the intermediate product W2 in cooperation with the gear die 32. A molding tooth 33b corresponding to the spline tooth Rb parallel to the gear axis formed on the clutch spline tooth portion Pb of the intermediate product W2 is provided on the inner peripheral surface of the upper part.
The upper and lower punches 33U and 33D are rotatably supported via upper and lower bearing plates 34U and 34D, the upper punch 33U is moved by an elevator 38 via an upper punch mounting base 37, and the lower punch 33D is moved into a hydraulic cylinder 35. The piston 36 that moves by supplying hydraulic oil can be moved up and down.
A lower knockout pin P1 is inserted into the lower punch 33D, and is operated by a knockout pin P2 penetrating the base 30, and an upper knockout pin P3 is inserted into the upper punch 33U, and an elevator base 38 is installed. It is operated by a knockout pin P4 that penetrates.
[0030]
Next, operation | movement of this rough tooth shaping | molding apparatus 3 is demonstrated.
By placing the intermediate product W2 on the lower punch 33D and lowering the elevating table 38, the intermediate product W2 is sandwiched and pressed between the upper punch 33U and the lower punch 33D to cause plastic deformation, and the gears for speed change At the same time, the helical teeth Ra are formed on the portion Pa, and the spline teeth Rb parallel to the gear axis line are simultaneously roughly formed on the clutch spline tooth portion Pb.
Thereafter, hydraulic oil is supplied into the hydraulic cylinder 35 to raise the piston 36 and push up the lower punch 33D. In this case, the piston 36 is raised until the molded intermediate product W3 is released from the gear die 32.
At this time, since the forming teeth 32a of the gear die 32 and the driven teeth 33a formed on the outer peripheral surface of the lower punch 33D are engaged with each other, when the lower punch 33D moves in the gear die 32, according to the movement amount, The lower punch 33D rotates, and the intermediate product W3 molded in accordance with this rotates together. As a result, the helical teeth Ra and spline teeth Rb parallel to the gear axis line respectively formed on the gear teeth Pa and clutch spline teeth Pb of the intermediate product W3 are taken out without being damaged. Can do.
That is, the intermediate product W3 is taken out by lifting the lift 38 and releasing the intermediate product W3 by the upper punch 33U and the lower punch 33D and then raising the piston 36 of the hydraulic cylinder 35 to raise the gear die 32. The helical teeth Ra formed on the gear teeth Pa for the intermediate product W3 are detached from the molding teeth 32a. Thereafter, by projecting the lower knockout pin P1 through the knockout pin P2 and the upper knockout pin P3 through the knockout pin P4, the clutch spline tooth portion of the intermediate product W3 is formed from the molding teeth 33b of the lower punch 33D. The spline teeth Rb parallel to the gear axis formed on Pb are released, and the intermediate product W3 is released from the upper and lower punches 33U and 33D.
[0031]
Next, the spline tooth forming process of FIG. 1 (12) will be described in detail.
In the spline tooth forming step, after the cold coining step (FIG. 1 (11)), the spline tooth Rb parallel to the gear axis roughly formed on the clutch spline tooth portion Pb is finished and then the intermediate product W5 is formed. Thus, spline teeth parallel to the gear axis formed on the clutch spline tooth portion Pb are formed into reverse tapered spline teeth Gb.
[0032]
An example of the spline tooth shaping | molding apparatus for implementing this spline tooth shaping | molding process is shown in FIGS.
This spline tooth forming apparatus 1 is for forming spline teeth parallel to the gear axis formed on the clutch spline tooth portion Pb into reverse-tapered spline teeth Gb, and the structure thereof will be described below.
The upper die 11 is disposed on the upper die mount 12 so as to be biased downward by the spring 12S.
The lower mold 13 facing the upper mold 11 is fixed to the lower mold mounting base 14, and the punch 15 is disposed on the lower mold mounting base 14 through the lower mold 13. A cylindrical knockout cylinder 16 operated by a knockout pin 20 is disposed, and a cylindrical case 17 is fixed to the lower mold mounting base 14. The case 17 has a cam that matches the inter-tooth angle and the number of teeth of the spline teeth Gb in order to form spline teeth Sb parallel to the gear axis formed on the clutch spline teeth Pb on the reverse-tapered spline teeth Gb. The insertion holes 17H are formed at a constant pitch, the outer surface of the cam insertion hole 17H is formed on the cam support surface 17F, and the cams 21 are respectively inserted into the cam insertion holes 17H.
The cam 21 inserted into the cam insertion hole 17H is supported by the lower mold mount 14 via a spring 24 and supported by an annular flange 18 operated by a knockout pin 19, and this annular flange. 18 is fixed by a bolt 21V.
In this case, the length of the knockout pin 19 and the knockout pin 20 is set so that the knockout pin 20 pushes up the knockout cylinder 16 after the knockout pin 19 pushes up the flange 18.
The rear surface of the cam 21 is finished with high precision so as to be in sliding contact with the cam support surface 17F of the case 17, and a pin 22 is provided on the inner side of the lower portion thereof so that the upper end side of the pin 22 is inclined inward. In addition, a die pressing surface 21T having an inclination angle equal to the inclination angle of the pin 22 is formed on the inner side surface of the cam 21 so as to face the pin 22.
As shown in FIG. 4, a die fitting insertion hole 13 </ b> H that matches the inter-tooth angle and the number of teeth of the reverse tapered spline teeth Gb is formed in the upper part of the lower mold 13 toward the center of the lower mold 13.
The die fitting insertion hole 13H has a substantially circular cross section and its top is cut into a flat shape, and each die fitting insertion hole 13H has a substantially circular cross section and its top cut into a flat shape. To be inserted. As a result, the dies 23 are arranged radially toward the center of the lower mold 13, and the case 17 is configured to hold the flat portion of the dies 23 and prevent the dies 23 from rotating.
The tip 23D of the die 23 is formed into a reverse-tapered spline tooth Gb by pressing the tip 23D against a spline tooth Sb parallel to the gear axis formed on the clutch spline tooth portion Pb and causing plastic deformation. It is formed in a shape that can. Further, the die 23 is provided with a pin insertion hole 23H for inserting the pin 22, and the rear end surface 23T of the die 23 is formed on an inclined surface corresponding to the die pressing surface 21T of the cam 21.
[0033]
Next, the operation of the spline tooth forming apparatus 1 will be described.
By placing the intermediate product W5 on the lower mold 13 and lowering the upper mold mount 12, the intermediate product W5 is sandwiched between the upper mold 11 and the lower mold 13 biased by the spring 12S, and When the die mount 12 is lowered, the upper surface of the cam 21 is pressed with a slight delay from the clamping of the intermediate product W5.
As a result, the cam 21 and the flange 18 are pushed down, the rear end surface 23T of the die 23 is pressed by the die pressing surface 21T of the cam 21, and each die 23 is directed in the direction toward the center of the lower die 13, that is, the intermediate product W5. The spline teeth Sb parallel to the gear axis formed on the clutch spline tooth portion Pb are formed into reverse-tapered spline teeth Gb at the tip 23D of the die 23.
Thereafter, the upper die mount 12 is raised, the knockout pin 19 is pushed up, and the flange 18 is raised. As a result, the cam 21 also rises. However, since the pin 22 inclined and projecting from the cam 21 is inserted into the pin insertion hole 23H of the die 23, each die 23 is The tip 23D of the die 23 is forcibly slid in the direction opposite to the center of the lower mold 13, and the tip 23D of the die 23 is detached from the intermediate product W6 formed with the reverse tapered spline teeth Gb.
When the intermediate product W6 is taken out, the tip 23D of the die 23 is detached from the intermediate product W6, and the reverse tapered spline tooth Gb formed on the clutch spline tooth portion Pb of the intermediate product W6 is damaged by the tip 23D of the die 23. After not receiving it, the knockout pin 20 is pushed up, and the knockout cylinder 16 is protruded to release the intermediate product W6 from the lower mold 13.
[0034]
Next, the gear forming step for speed change by flow forming in FIG. 1 (14) will be described in detail.
The gear forming process for speed change by flow forming is based on the clutch spline tooth portion Pb formed with the reverse tapered spline tooth Gb formed in the final finished dimension by the spline tooth forming process of FIG. While the intermediate product W7 in which H is formed is rotated about the shaft hole H as a central axis, the gear teeth Ra that are roughly formed on the gear teeth Pa for speed change are finished and formed into gear teeth Ga for transmission.
[0035]
An example of a flow forming apparatus for carrying out this gear forming step for speed change by flow forming is shown in FIGS.
The flow forming apparatus 7 finish-molds the helical teeth Ra as the gear teeth for shifting roughly formed on the gear teeth for shifting Pa into the helical teeth Ga as gear teeth for shifting, and the structure thereof will be described below.
[0036]
The flow forming apparatus 7 is driven by the rotation of the tailstock part 4 which cooperates with the tailstock part 4 which can rotate forward and reverse alternately, the chuck part 5 which holds the intermediate product W7 in cooperation with the tailstock part 4. The helical tooth Ra roughly formed on the gear teeth Pa for the intermediate product W7 is composed of a rolling die portion 6 for finish-molding the helical tooth Ga.
The tail stock portion 4 is configured by fixing a synchronization gear 42, a receiving die 43 and a collet chuck 44 with bolts 45 at the tip of a tail stock 41 which can be rotated forward and backward alternately.
In this case, the synchronous gear 42 has at least its teeth projecting from the tail stock 41, and its teeth are in phase with the helical tooth Ga to be molded (the helical tooth Ra roughly formed on the shifting gear portion Pa). To use.
Further, the receiving die 43 is formed with a spline tooth-shaped recess corresponding to the reverse tapered spline tooth Gb formed in the clutch spline tooth portion Pb of the intermediate product W7.
The chuck portion 5 fixes a clamp die 52 and a male cone 54 to a rotatable chuck receiving base 51 disposed opposite to the tail stock portion 4 with bolts 55 and is arranged on the outer periphery of the clamp die 52. The provided stripper 53 is configured to be engaged with the rod 56.
Then, by moving the chuck portion 5 forward, the intermediate product W7 and the clutch spline tooth portion of the intermediate product W7 are disposed by the receiving die 43 of the tail stock portion 4 and the clamp die 52 of the chuck portion 5 which are arranged to face each other. The inversely tapered spline teeth Gb formed on Pb are received and fitted into the spline tooth-shaped recesses formed on the die 43 so as to be clamped.
Thereby, the phase of the helical gear Ra and the synchronous gear 42 which are roughly formed on the gear teeth Pa for the intermediate product W7 coincides.
Further, the intermediate product W7 is held by the male cone 54 of the chuck portion 5 being inserted into the collet chuck 44 of the tail stock portion 4 and expanding the claw piece 44a of the collet chuck 44. It is accurately held with the shaft hole H of W7 as the central axis.
Further, the stripper 53 is slidably disposed on the outer periphery of the clamp die 52 fixed to the chuck cradle 51, and is engaged with the tip of the rod 56 penetrating the chuck cradle 51, and the base end of the rod 56 is attached. The fixed mounting base 57 is supported so as to be movable in the axial direction of the chuck receiving base 51.
Then, after forming the helical teeth Ga, the chuck cradle 51 is retracted to release the intermediate product W8 between the receiving die 43 and the clamp die 52, and the stripper 53 protrudes through the rod 56. The intermediate product W8 fitted to the clamp die 52 can be released.
The rolling die portion 6 includes a moving table 61 that moves in parallel with the tail stock 41, and a rolling spindle 62 that is disposed on the moving table 61 in parallel with the tail stock 41 via bearings 63 and 63. And a driven gear 64 and a rolling die 65 which are disposed on the rolling spindle 62 and mesh with the synchronous gear 42.
[0037]
Next, the operation of the flow forming apparatus 7 will be described.
By moving the chuck portion 5 forward, the intermediate product W7 is sandwiched between the receiving die 43 of the tail stock portion 4 and the clamp die 52 of the chuck portion 5 which are disposed to face each other, and the rolling die portion 6 is moved. The base 61 is translated with respect to the tail stock 41, and the driven gear 64 is engaged with the synchronous gear 42, and the rolling die 65 is engaged with the helical tooth Ra roughly formed on the gear changing tooth portion Pa of the intermediate product W7. Like that.
By rotating the tail stock 41, the intermediate product W7 and the chuck portion 5 are rotated. In this case, the tail stock 41 is preferably configured to perform forward and reverse rotation alternately and alternately at a predetermined cycle.
On the other hand, the rotation of the tail stock 41 is transmitted to the rolling die 65 via the synchronous gear 42, the driven gear 64 and the rolling spindle 62, and the rolling die 65 rotates in synchronization with the synchronous gear 42.
As a result, the intermediate product W7 meshed with the rolling die 65 is rotated by the tailstock 41, so that it is roughly formed in the gear teeth Pa for transmission while rotating in synchronization with the rolling die 65. The helical tooth Ra is finish-formed into the helical tooth Ga by forging with the rolling die 65.
The intermediate product W8 formed with the helical teeth Ga is taken out by retracting the chuck cradle 51 to release the intermediate product W8 from being held by the receiving die 43 and the clamp die 52, and the stripper 53 via the rod 56. By projecting, the intermediate product W8 fitted to the clamp die 52 is released.
[0038]
As described above, in the gear for shifting according to the present invention and the manufacturing apparatus therefor, the gear teeth for shifting in the form shown in FIGS. 11 (A) and 11 (B), in which the helical teeth Ga as gears for shifting are formed in the gear teeth Pa for shifting. Although the gear W has been described as an example, the subject of the present invention is not limited to the gear for shifting in this form, and can be appropriately changed without departing from the gist thereof.
[0039]
More specifically, the speed change gear W to which the present invention is applied includes not only helical gear teeth but also flat teeth, and further, in FIGS. 10 (C) and 10 (D). As shown, those having a crowning Ca on the tooth surface of the gear teeth Ga for transmission are included (of course, those having no crowning Ca are also included).
In this case, by appropriately selecting the shape of the rolling die 65 of the flow forming device 7, the speed change tooth Ra roughly formed on the speed change tooth portion Pa of the intermediate product W 7 is forged by the rolling die 65 for speed change. When finish-molding the teeth Ga, the crowning Ca can also be formed on the tooth surfaces of the gear teeth for transmission Ga.
[0040]
In addition, the gear W for transmission targeted by the present invention is difficult to machine by the method of forming the gear Ga for gear shifting by machining such as hobbing in the gear teeth Pa, as shown in FIG. As shown, the diameter Db of the tip circle of the reverse tapered spline tooth Gb formed on the clutch spline tooth portion Pb is larger than the diameter Da of the root circle of the gear tooth Ga for shifting formed on the tooth portion Pa for shifting, Further, the gear teeth Pa and the clutch spline teeth as shown in FIG. 10C, in which the gap t of the groove Na formed between the gear teeth Pa and the clutch spline teeth Pb is 2 mm or less. In some cases, a partition wall Nb is formed between Pb (as shown in FIG. 10A), and a gap t between grooves Na formed in the gear teeth Pa and the clutch spline teeth Pb is larger than 2 mm. Can be manufactured.).
[0041]
【The invention's effect】
According to the present invention, the gear teeth for shifting and the clutch spline teeth including the gear teeth for shifting and the reverse tapered spline teeth having the chamfer at the tip can be integrally formed by forging. The effect of this is achieved.
(1) By forming the gear teeth for shifting and the reverse tapered spline teeth having chamfers at the tips by forging, the metal flow of the teeth is not cut, the strength of the gears is improved, and manufacturing by machining The increase in cost can be avoided, and the manufacturing cost of the transmission gear can be reduced.
(2) It is easy to ensure the concentricity of the clutch spline tooth portion formed with the tapered spline teeth and the speed change tooth portion formed with the gears for speed change, and a high-accuracy speed change gear can be manufactured. it can.
(3) When forming helical teeth as gears for shifting, there is no difference in the twist angle between the tooth surfaces on both sides, and it is possible to manufacture gears with high accuracy, especially helical gears with a twist angle of 30 ° or more. Teeth can also be formed by forging.
(4) When the speed change teeth are finished by forging, a crowning can be formed on the tooth surface of the speed change teeth.
(5) The shift feeling is coupled with the fact that a reverse gear with a chamfer at the tip is formed by forging to produce a high-accuracy transmission gear without being caught by machining. Can be obtained.
(6) Since there are no restrictions on the constituent materials of the transmission gear, for example, difficult-to-cut high-strength steel can be used, and a small transmission gear can be easily manufactured.
(7) A shift gear having a shape difficult to machine can be manufactured, and a small shift gear can be obtained.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a manufacturing process of a transmission gear according to the present invention.
FIG. 2 is a front cross-sectional view of a rough tooth forming apparatus used for manufacturing a transmission gear according to the present invention.
FIG. 3 is a front sectional view of a spline gear forming apparatus used for manufacturing a transmission gear according to the present invention.
4A and 4B show a lower mold of the spline tooth forming apparatus, in which FIG. 4A is a plan view and FIG.
5A and 5B show a die of the spline tooth forming apparatus, in which FIG. 5A is a plan view, FIG. 5B is a partially cutaway front view, and FIG. 5C is an explanatory view of the tip of the die.
FIG. 6 is a front sectional view of a flow forming apparatus used for manufacturing a transmission gear according to the present invention.
FIG. 7 is an enlarged view of the main part.
FIG. 8 is an explanatory diagram showing a relationship between a synchronous gear and a driven gear.
FIG. 9 is an explanatory diagram showing a relationship between a rolling die and an intermediate product.
FIG. 10 is an explanatory diagram of various speed change gears.
11A and 11B are explanatory views of a typical transmission gear, in which FIG. 11A is a cross-sectional view, FIG. 11B is a development view of a main part, and FIG.
[Explanation of symbols]
1 Spline tooth forming device
3 Coarse tooth forming device
7 Flow forming equipment
W Gear for shifting
W0 material
W1, W2, ..., W8 Intermediate products
Pa Gear teeth
Pb Clutch spline teeth
Ra gear teeth (coarse teeth)
Rb spline teeth (coarse teeth)
Sb spline teeth (intermediate teeth)
Ga gear teeth (finishing teeth)
Gb Reverse tapered spline teeth (finished teeth)
Ca Crowning
Cb Changfa

Claims (7)

It has a shaft hole in the center and a gear tooth for shifting and a clutch spline tooth portion integrally formed by forging on the outer peripheral surface in order in the axial direction. In the transmission gear formed by forging reverse-tapered spline teeth having a gear, the gear-shifting teeth of the gear-shifting tooth portion are formed with reference to the outer peripheral surface of the clutch spline tooth portion forming the reverse-tapered spline teeth . A shaft hole whose peripheral surface is turned is held by a chuck means , and the gear teeth for shifting are formed by forging with a rolling die on the gear teeth for shifting, and the root circle of the gear teeth for shifting formed on the gear teeth for shifting. The diameter of the tip of the reverse-tapered spline teeth formed on the clutch spline teeth is larger than the diameter of the gear and the gap between the gear teeth for shifting and the clutch spline teeth is 2 mm or less. Transmission gear for the butterflies.   The speed change gear according to claim 1, wherein the speed change teeth are helical teeth.   The speed change gear according to claim 1 or 2, wherein the speed change tooth has a crowning on a tooth surface. It has a shaft hole in the center and a gear tooth for shifting and a clutch spline tooth portion integrally formed by forging on the outer peripheral surface in order in the axial direction. In the manufacturing apparatus of a transmission gear for forming a reverse-tapered spline tooth having forging by the forging , the clutch spline tooth portion is formed at the center of the gear to be processed in which the clutch spline tooth portion formed by forging the reverse-tapered spline tooth is formed. Chuck means for holding a shaft hole in which the inner peripheral surface is turned with reference to the outer peripheral surface of the shaft, a tail stock for rotating the gear to be processed around the shaft hole through the chuck means, and the tail A synchronous gear disposed on the stock and rotating together with the tail stock; a driven gear and a rotational gear disposed parallel to the tail stock and meshing with the synchronous gear; Consists of a rolling spindle which is disposed a die, the workpiece gear, by rotating the tail stock, through the chuck means, while rotating the shaft hole as the center axis, the synchronization gear and the driven gear Thus, the shift die that rotates in synchronism with the gear to be machined is used to perform finish forming of the gear for shifting gear that has been rough formed in advance on the gear tooth for gear shifting of the gear to be machined. Gear manufacturing equipment.   The chuck means comprises a collet chuck and a male cone that is fitted into the collet chuck and expands the diameter of the collet chuck so as to hold a shaft hole drilled at the center of the gear to be processed. The gearshift gear manufacturing apparatus according to claim 4. 6. The apparatus for manufacturing a transmission gear according to claim 4 , wherein the rolling die performs finish molding of helical teeth that are rough formed in advance by forging on the gear teeth of the gear to be processed. 7. The rolling die according to claim 4, 5 or 6, wherein a crowning is formed on a tooth surface of a speed change tooth that is roughly formed in advance by forging on a speed change tooth portion of a gear to be processed. An apparatus for manufacturing the gear for shifting described.

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