JP4915384B2 - Method for manufacturing hollow gear - Google Patents

Description

  The present invention relates to a method for manufacturing a hollow gear, and more particularly to a method for manufacturing a hollow gear having a through hole in a disk portion.

  A power transmission device provided in a vehicle such as an automobile transmits power from an internal combustion engine to drive wheels via a plurality of gears. For example, in a power transmission device provided in a hybrid vehicle, power transmitted from an internal combustion engine or motor generator to an input shaft is transmitted to a counter driven gear via a ring gear of a planetary gear device, and then this counter driven gear. After being transmitted to the differential device via a final drive gear coupled to the power, power is transmitted to the left and right drive wheels via the differential device.

  By the way, the noise generated in the power transmission device includes noise generated by rotation of planetary gears, counter driven gears, final drive gears, shafts, bearings, etc., and these vibrations propagate to the case of the power transmission device, etc. Is roughly classified into noise generated by resonance.

  Conventionally, noise generated in this power transmission device has been reduced mainly by taking measures such as adding ribs to the case of the power transmission device and preventing resonance of the case of the power transmission device. It was being tried.

  However, in recent years, the reduction in noise of the internal combustion engine, the reduction of noise generated by the rotation of the tire, the reduction of wind noise due to the improvement of the body, etc. have been reliably realized. It is becoming impossible to ignore the noise generated in

  In addition, in recent years, restrictions on the space for mounting the power transmission device on the vehicle and the weight of the power transmission device itself have become more severe. It has become very difficult. For this reason, it is necessary to develop a noise reduction technique other than measures for the case of the power transmission device.

  In response to such demands, there are gears designed to reduce noise and reduce transmission weight. A manufacturing method of such a gear includes a hollow small-diameter annular portion, a disk extending radially from the small-diameter annular portion in a direction perpendicular to the rotation axis of the small-diameter annular portion, and having teeth on the radially outer end face And a through hole is formed in the disk part.

As a manufacturing method of this gear, a hollow blank composed of a hollow small-diameter annular portion and a disk portion extending radially from the small-diameter annular portion is formed by forging, and then cut to the radial outer end of the disk portion. Then, the tooth part is formed, and then the tooth surface of the tooth part is subjected to shaving (see, for example, Patent Document 1).
As a process after this, there is a process in which a hollow gear as a product is manufactured by forming a through hole in a disk part by laser processing after performing a heat treatment step such as quenching on a hollow blank. (For example, refer to Patent Document 2).

In the shaving process, it is common to hold the hollow blank with a gripping portion provided in the shaving device, and shaving the tooth surface of the tooth portion of the hollow blank with a shaving cutter provided in the shaving device. is there.
In addition, when a through hole is formed in the disk part by laser processing, the through hole is formed by laser processing the disk part in a state where the hollow blank is held by the holding part provided in the laser processing apparatus. It is common.

  The hollow gear formed in this way is used as a counter driven gear, the small-diameter annular portion is spline-fitted to the rotary shaft of the final drive gear, and the counter driven gear and the ring gear of the planetary gear device are engaged with each other. Allowing elastic deformation in the radial direction and tangential direction when meshing, and when the counter driven gear and the ring gear mesh with each other, the noise generated by the collision between the counter driven gear and the ring gear and the occurrence of vibration, and the counter driven gear Due to fluctuations in the load applied to the ring gear, noise caused by vibrations caused by fluctuations in the timing of meshing between the counter-driven gear and the ring gear is reduced, and these vibrations propagate to the case of the power transmission device, etc. Etc. resonate It can be suppressed.

Further, since the counter driven gear is thinned by forming the through hole in the counter driven gear, the counter driven gear can be reduced in weight, and as a result, the power transmission device can be reduced in weight.
JP 7-136863 A JP 2006-266495 A

  However, in such a conventional hollow gear manufacturing method, when the hollow blank is subjected to shaving and when the through hole is formed in the disk portion, the hollow blank is provided as a single unit in the shaving device. Therefore, there is a problem that a sufficient gripping force cannot be ensured and the workability of the working process of the tooth portion and the through hole is low.

  The present invention has been made to solve the conventional problems as described above, and can easily process the tooth portion and the through hole, thereby improving the workability of the processing operation of the tooth portion and the through hole. An object of the present invention is to provide a method for manufacturing a hollow gear.

  In order to achieve the above object, a method for manufacturing a hollow gear according to the present invention includes (1) a hollow small-diameter annular portion, a radial portion extending from the small-diameter annular portion, and a tooth portion on the radially outer end surface. A hollow gear manufacturing method comprising: a disk portion, wherein a through hole is formed in the disk portion, wherein the hollow gear having a plurality of teeth pre-processed at a radially outer end of the disk portion is heat treated. Preparing a rotating shaft having a power transmission gear formed on an outer peripheral portion and after the heat treatment step, assembling the small-diameter annular portion to the rotating shaft of the power transmission gear; and after the assembling step, the rotating shaft And then, after the tooth polishing step, the rotating shaft is held and the through hole is formed in the disk portion. Through hole formation Comprising a degree.

By this method, in tooth polishing after heat treatment, the rotating shaft is gripped in a state where the small-diameter annular portion is assembled to the rotating shaft of the power transmission gear, and the tooth surface of the tooth portion of the disk portion is polished by the polishing device. Therefore, a sufficient gripping force can be ensured during polishing of the tooth surface of the tooth portion, and the tooth portion can be easily processed. For this reason, workability | operativity of the process operation | work of a tooth part can be improved.
Also, in the through hole forming process after tooth polishing, the rotary shaft is gripped and the through hole is formed in the disk portion with the small-diameter annular portion assembled to the rotary shaft of the power transmission gear. Sufficient gripping force can be ensured, and the through hole can be easily processed. For this reason, workability | operativity of the processing operation of a through-hole can be improved.

  In addition, when the through hole is formed in the disk part before the tooth surface of the tooth part is ground, there is a risk of chattering in the tooth part, but in the present invention, after the tooth surface of the tooth part is ground, Since the through hole is formed in the disk portion, it is possible to prevent the tooth portion from chattering and to prevent the processing accuracy of the tooth portion from being lowered.

  In the manufacturing method of the hollow gear described in (1) above, (2) in the through hole forming step, the through hole is formed radially outward from the radial outer end surface of the power transmission gear. .

  By this method, since the through hole is formed radially outward from the radial outer end face of the power transmission gear, the radial outer space of the power transmission gear can be used when forming the through hole, It is possible to prevent the power transmission gear from obstructing the formation of the through hole.

In the method for manufacturing a hollow gear according to the above (1) or (2), (3) the through hole forming step is performed by laser processing.
By this method, since the through hole is formed by laser processing, the through hole can be formed by non-contact processing, and burrs and the like can be prevented from being generated in the hollow gear.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the hollow gear which can process a tooth part and a through-hole easily, and can improve the workability | operativity of a tooth part and a through-hole process can be provided.

Hereinafter, embodiments of a method for manufacturing a hollow gear according to the present invention will be described with reference to the drawings.
FIGS. 1-6 is a figure which shows one Embodiment of the manufacturing method of the hollow gear based on this invention, and has shown the example which applied the hollow gear to the power transmission device of vehicles, such as a motor vehicle.

First, the configuration will be described.
In FIG. 1, the power transmission device 1 has a transmission case 2 in which a differential planetary gear device 3 constituting a transmission mechanism and differential outputs to front drive shafts 33 and 34 are provided. Differential device 4 that can be driven, drive motor 5 that drives the vehicle with stored electric power, motor generator 6 that can generate electric power by power from an engine (not shown), and oil pump that supplies oil to each part of power transmission device 1 7 is stored.

  The compound planetary gear unit 3 includes a first planetary gear unit 11 that transmits power output from the drive motor 5 and a second planetary gear unit 12 that transmits power output from the engine. The power output from the drive motor 5 and the engine can be selectively transmitted to the differential device 4.

The transmission case 2 includes a housing 13 that is fastened and supported on the engine side, and a case 14 that is fixed to an opening end of the housing 13 opposite to the engine side.
A case cover 15 is attached to the opening end of the case 14 opposite to the housing 13 side, and an oil pump cover 16 is attached to the case cover 15 on the opposite side of the case 14 side.

  A housing cover 17 is attached to the housing 13, and the inside of the housing 13 is defined by a storage portion of the motor generator 6 and a storage portion of a damper element 18 that is a driving force transmission mechanism from the engine.

  An input shaft 19 that extends through the motor generator 6 and the second planetary gear device 12 is disposed at the rotation center portion of the motor generator 6 and the second planetary gear device 12. An oil pump drive shaft 20 extending through the drive motor 5 and the first planetary gear unit 11 is disposed at the rotation center portion of the first planetary gear unit 11 and the first planetary gear unit 11.

  One end of the input shaft 19 is integrally engaged with the crankshaft 21 in the rotational direction, and the other end is connected to the second planetary gear unit 12, and power from the engine is supplied to the compound planetary gear unit 3. To communicate.

  One end of the oil pump drive shaft 20 is integrally engaged with the input shaft 19 in the rotational direction, and the other end is connected to the oil pump 7, and transmits power from the input shaft 19 to the oil pump 7. It is like that.

  The transmission case 2 is provided with a counter driven gear 22 and a final drive gear 23 that transmit the power output from the compound planetary gear device 3 to the differential device 4.

  The counter driven gear 22 meshes with the counter drive gear 24 of the compound planetary gear device 3, and the counter driven gear 22 is spline-fitted to a counter shaft 25 as a rotating shaft integrally formed with the final drive gear 23. .

  The differential device 4 includes a hollow differential case 26. A final gear 27 that meshes with the final drive gear 23 is fastened to the outer peripheral portion of the differential case 26, and the power output from the compound planetary gear device 3 is the final gear 27. It is transmitted to the differential case 26 via.

  A pinion gear shaft 28 is rotatably supported in the differential case 26, and a pair of differential pinion gears 29 and 30 are fixed to the pinion gear shaft 28.

  Each differential pinion gear 29, 30 has two side gears 31, 32 engaged with each other, and front drive shafts 33, 34 are connected to the side gears 31, 32, respectively. The front wheels (not shown) are respectively fixed.

  In the present embodiment, the counter driven gear 22 of the power transmission device 1 configured as described above is spline-fitted to the counter shaft 25 of the final drive gear 23 as a power transmission gear, so that the counter driven gear 22 is a hollow gear. The counter-driven gear 22 is manufactured in a characteristic manner.

  2 and 4, the counter driven gear 22 includes a hollow small-diameter annular portion 41 having a spline portion 41a on the inner peripheral portion, a radial portion extending from the small-diameter annular portion 41, and a tooth portion 42 on the radially outer end surface. And three through holes 44 are formed in the disk portion 43.

  The spline portion 41 a of the small-diameter annular portion 41 is spline-fitted to the spline portion 25 a of the counter shaft 25, so that the counter driven gear 22 is attached to the counter shaft 25.

  Further, in a state where the counter driven gear 22 is assembled to the counter shaft 25 of the final drive gear 23, the through hole 44 of the disc portion 43 is formed radially outward from the radial outer end surface of the final drive gear 23. .

Next, a manufacturing method of the counter driven gear 22 will be described based on the manufacturing procedure of FIG.
First, the material is forged into a predetermined shape (forging process A). Next, the hollow blank of the counter-driven gear 22 (product) obtained in the forging process A is hypoid geared to form a plurality of tooth portions 42 at the radially outer end of the hollow blank corresponding to the disk portion 43 (tooth cutting). Step B). Further, the spline portion 41 a is processed in the inner peripheral portion of the hollow blank corresponding to the small-diameter annular portion 41.

  Next, the hollow blank is heat-treated (heat treatment step C). In this heat treatment step C, for example, gas carburization and oil quenching are performed. Specifically, after heating the hollow blank in a carburizing gas atmosphere at 930 ° C. for 5 hours, diffusing at 850 ° C. for 1 hour, and then quenching at 130 ° C., then tempering at 180 ° C. for 1 hour Carburizing and tempering at.

  Next, as shown in FIG. 4, the counter driven gear 22 is attached to the counter shaft 25 by spline fitting the spline portion 41 a of the small-diameter annular portion 41 to the spline portion 25 a of the counter shaft 25 (assembly step D).

Next, as shown in FIG. 5, both end portions of the counter shaft 25 to which the counter driven gear 22 is assembled are gripped by the clamp portions (gripping portions) 52 of the polishing device 51, and the tooth surfaces 42 a of the tooth portions 42 of the disc portion 43 are formed. Polishing is performed by the polishing tool 53 of the polishing apparatus 51 (tooth polishing step E).
Specifically, the polishing tool 53 has a gear shape having a convex portion for polishing that meshes with the tooth portion 42 of the disk portion 43, and the polishing tool 53 and the hollow blank are rotated together with the polishing tool 53. The tooth surface 42a of the tooth portion 42 is polished by the convex portion.

Next, as shown in FIG. 6, both end portions of the counter shaft 25 to which the counter driven gear 22 is assembled are gripped by the clamp portions (gripping portions) 62 of the laser processing device 61, and laser light is applied from the laser processing device 61 to the disk portion 43. By irradiating L, three through holes 44 are formed along the irradiation circumferential direction of the disk portion 43 (through hole forming step F).
The laser processing device 61 is composed of an optical system using a laser oscillator, and when the laser beam L is irradiated to the disk portion 43 by the laser processing device 61, the disk portion 43 is melted or evaporated to penetrate. A hole 44 is formed.

As described above, in the manufacturing method of the counter driven gear 22 according to the present embodiment, the heat treatment step C in which the counter driven gear 22 is heat-treated after the gear cutting step B and the counter shaft 25 having the final drive gear 23 formed on the outer peripheral portion are provided. After the heat treatment step C, an assembly step D for assembling the small-diameter annular portion 41 to the countershaft 25, and after the assembly step D, the countershaft 25 is held by the clamp portion 52 of the polishing apparatus 51 and the polishing tool 53 of the polishing apparatus 51 is obtained. The tooth surface 42a of the tooth portion 42 of the disk portion 43 is ground by the tooth polishing step E, and after the tooth polishing step E, the countershaft 25 is gripped by the clamp portion 62 of the laser processing device 61, and the disc portion 43 has a through hole. The tooth portion is manufactured by the manufacturing process including the through hole forming process F for forming 44. During polishing of the second tooth surface 42a can ensure a sufficient gripping force, it can be easily processed in the teeth 42. For this reason, workability | operativity of the process of the tooth part 42 can be improved.
In addition, a sufficient gripping force can be secured when the through hole 44 is processed, and the through hole 44 can be easily processed. For this reason, workability | operativity of the processing operation of the through-hole 44 can be improved.

  Further, if the through hole is formed in the disk portion 43 before the tooth surface 42a of the tooth portion 42 is polished, the tooth portion 42 may be chattered. In this embodiment, the tooth surface 42a of the tooth portion 42 is formed. Since the through-hole 44 is formed in the disk portion 43 after the polishing process is performed, the tooth portion 42 can be prevented from chattering, and the processing accuracy of the tooth portion 42 can be reduced. Can be prevented.

  In the present embodiment, since the through hole 44 is formed radially outward from the radial outer end surface of the final drive gear 23 in the through hole forming step, the final drive gear 23 is formed when the through hole 44 is formed. Thus, it is possible to prevent the final drive gear 23 from obstructing the operation of forming the through hole 44.

  In the present embodiment, since the through-hole 44 is formed by laser processing in the through-hole forming step, the through-hole 44 can be formed by non-contact processing, and the disk portion 43 of the counter driven gear 22 can be formed. Generation | occurrence | production of a burr | flash etc. can be prevented.

  In the present embodiment, the method of manufacturing the counter driven gear 22 used in the vehicle power transmission device 1 is shown as a method of manufacturing the hollow gear. However, the present invention is not limited to this, and a power transmission gear is formed on the outer peripheral portion. The manufacturing method may be applied to any form of hollow gear as long as the toothed portion can be formed in a state where the rotating shaft is assembled.

  The embodiment disclosed this time is illustrative in all respects and is not limited to this embodiment. The scope of the present invention is shown not by the above description of the embodiments but by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

  As described above, the hollow gear manufacturing method according to the present invention can easily process the tooth portion and the through hole, and can improve the workability of the processing operation of the tooth portion and the through hole. And is useful as a method for producing a hollow gear having a through hole in the disk portion.

It is a figure which shows one Embodiment of the manufacturing method of the hollow gear which concerns on this invention, and is a block diagram of the power transmission device provided with the counter driven gear which is a hollow gear. It is a figure which shows one Embodiment of the manufacturing method of the hollow gear which concerns on this invention, and is a front view of a counter driven gear. It is a figure which shows one Embodiment of the manufacturing method of the hollow gear which concerns on this invention, and is a figure which shows the manufacturing procedure of a counter driven gear. It is a figure which shows one Embodiment of the manufacturing method of the hollow gear which concerns on this invention, and is a figure which shows the state which assembled | attached the counter driven gear to the final drive gear. It is a figure which shows one Embodiment of the manufacturing method of the hollow gear which concerns on this invention, and is a figure which shows the state which grind | polishes the tooth surface of the tooth part of a counter driven gear. It is a figure which shows one Embodiment of the manufacturing method of the hollow gear which concerns on this invention, and is a figure which shows the state which forms a through-hole in a counter driven gear.

Explanation of symbols

22 Counter driven gear (hollow gear)
23 Final drive gear (power transmission gear)
25 Counter shaft (Rotating shaft)
41 Small-diameter annular portion 42 Tooth portion 42a Tooth surface 43 Disc portion 44 Through hole A Forging process B Gear cutting process C Heat treatment process D Assembly process E Tooth polishing process F Through hole formation process

Claims (3)

A hollow small-diameter annular portion having spline teeth formed at the radially inner end, and a disk portion extending radially from the small-diameter annular portion and having a tooth portion on the radially outer end surface, the disk portion A method of manufacturing a hollow gear in which a through hole is formed,
A heat treatment step of heat-treating the hollow gear in which a plurality of tooth portions are pre-processed at the radial outer end of the disk portion and the spline teeth are processed in the small-diameter annular portion ;
By preparing a rotating shaft having a power transmission gear formed on the outer peripheral portion and, after the heat treatment step , by spline-fitting the small-diameter annular portion to spline teeth formed on the outer peripheral portion of the rotating shaft of the power transmission gear , An assembling step of assembling the disk portion to the rotating shaft ;
A tooth polishing step of gripping the rotating shaft after the assembly step and then polishing the tooth surface of the tooth portion of the disk portion by a polishing device;
A hollow gear manufacturing method comprising: a through hole forming step of gripping the rotating shaft and forming the through hole in the disk portion after the tooth polishing step. 2. The method for manufacturing a hollow gear according to claim 1, wherein, in the through-hole forming step, the through-hole is formed radially outward from a radially outer end face of the power transmission gear. The method for manufacturing a hollow gear according to claim 1, wherein the through-hole forming step is performed by laser processing.

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