JP5318675B2 - Method and structure for fixing internal gear of planetary speed reducer and planetary speed reducer - Google Patents

Description

  The present invention relates to an internal gear fixing method and a fixing structure of a planetary reduction gear for fixing an internal gear and a gear case of a reduction gear provided with a planetary gear mechanism, and a planetary reduction gear.

Conventionally, in a planetary reduction gear that employs a planetary gear mechanism as a reduction gear, for example, there are the following methods for fixing an internal gear and a gear case.
(A) A method in which the gear case 100 and the internal gear 101 are processed separately and the gear case 100 and the internal gear 101 are fixed by bolts 102 (see FIG. 8).
(B) A method in which the gear case and the internal gear are processed separately and the gear case and the internal gear are fixed by knurling (see Patent Document 1).
(C) A method in which the gear case and the internal gear are processed separately and the gear case and the internal gear are fixed by press-fitting.
(D) A method in which the gear case and the internal gear are processed separately, and the gear case and the internal gear are fixed by using both knurled coupling and press-fit coupling (see Patent Document 2).
(E) A method of integrating the gear case 103 and the internal gear 103a (see FIG. 9).

In the fixing method of the internal gear and the gear case, it is necessary to achieve the following problems.
(A) Accuracy (coaxiality and squareness between the housing of the gear case in which the bearing supporting the rotation is arranged and the internal gear)
(B) Fixing force (fixing strength between the internal gear and the gear case sufficient for the transmission torque of the planetary reduction gear)
(C) Gear strength (The inner gear diameter can be increased. This makes it possible to design gear specifications with high strength.)
(D) Manufacturing cost

However, in the conventional method,
The bolt connection in (a) requires a bolt through hole to be processed, and thus increases the manufacturing cost in (D).
Further, in a planetary speed reducer that requires high-precision positioning due to misalignment (assembly error), it is difficult to obtain a structural design that can maintain the accuracy of (A).
The knurled connection (b) is effective in terms of securing a high fixing force (B) in the circumferential direction. However, depending on the accuracy of the knurling process and the variation in biting during press-fitting of the knurled part (A) In a planetary reduction gear that requires high-precision positioning, it is difficult to obtain a structural design that can maintain accuracy.
The press-fit coupling (c) is effective in ensuring the accuracy of (A), but in order to always secure a high fixing force (B) in the circumferential direction regardless of the heat change, ensure strict dimensional accuracy. There is a problem that the manufacturing cost (D) required for dimensional management is increased. Therefore, there is a method of reducing the dimensional accuracy by using an adhesive, but in such a case, a new process of applying an adhesive is added, so that the assembly workability is deteriorated and the adhesive application varies by the operator. There was a risk of deteriorating the stability of the holding force.
(D) Combined use of knurling and press-fitting is such that a cylindrical press-fitting part and a knurled press-fitting part are provided for the inner gear, and the gear case and the internal gear are aligned with each other while the cylindrical press-fitting part is centered. This is a method of securing the fixing force in the circumferential direction (B). However, although the coaxiality of (A) with the bearing housing of the gear case can be obtained by centering with the cylindrical press-fitting part, it is press-fitted in the circumferential direction due to the accuracy of the knurling process and the variation in the biting when the knurled part is pressed. Since there is a difference in resistance, there is a problem in that the resistance is tilted toward the lower side and the perpendicularity of (A) is affected.
There is a method of correcting the inclination by abutting the end face of the internal gear and the end face of the gear case at the end of press-fitting, but for that purpose, not only the accuracy of the abutment surface of the gear case and the internal gear but also the accuracy of the abutment surface of the press-fit device As a result, the manufacturing cost of (D) may be increased.

The fixing methods (a), (b), (c), and (d) above are methods in which the gear case and the internal gear are processed separately to fix the two parts.
Therefore, although depending on the method, the accuracy of (A) is deteriorated by performing the process of fixing two parts in any method. Furthermore, in order to alleviate this deterioration of accuracy as much as possible, it was necessary to finish the two parts with high accuracy.
Further, in order to obtain the gear strength of (C), it is necessary to increase the diameter of the internal gear. However, in the fixing methods (a), (b), (c), and (d), the gear case and the internal gear are separate. Because it is necessary to arrange the internal gear inside the gear case, it is necessary to make the internal gear extremely thin in order to increase the gear diameter, and it was difficult to obtain a high strength gear specification design. .

Furthermore, since the fixing methods (b), (c), and (d) are all press-fitted, deformation such as swelling occurs after the press-fitting.
This deformation not only affects the gear accuracy but also adversely affects the assembly when the press-fitted part is used for an inlay joint or the like.

Japanese Patent Laid-Open No. 6-174027 JP 2000-274494 A No. 5-26308

The integral structure (e) is a method of manufacturing the internal gear and the gear case integrally. Therefore, there is no deterioration in accuracy caused by fixing the two components, and the accuracy of (A) can be maintained with high accuracy. Further, since the inner gear diameter can be increased by the integrated structure, the gear specifications having high gear strength (C) can be achieved. However, in order to realize an integrated structure, the material is cut out from the material, the amount of cutting is large, and the machining process is complicated because it includes chamfering and mounting drilling necessary as a gear case. Furthermore, in order to obtain the hardness as an internal gear, the alloy steel is subjected to cutting after heat treatment, and there has been an increase in tool wear and processing time due to cutting a material with high hardness. In addition, since the mass of the material is larger than that of the internal gear in the methods (a), (b), (c), and (d), when performing heat treatment such as quenching and tempering, a critical cooling rate is obtained to the inside of the material. There is also a problem that heat treatment is difficult. Further, in actual use, the outer portion is in a state where the alloy steel is exposed, so that it is easily affected by rust, and in applications where water is applied, rust prevention treatment such as plating is required. As a result, there is a problem that the manufacturing cost of (D) increases.

  Although there is a method of casting the gear case and the internal gear integrally with an aluminum alloy (see Patent Document 3), the above problem can be solved, but the accuracy of (A) depends on the casting process, and it is difficult to maintain high accuracy. Met. Even if finishing is performed, it is difficult to perform processing based on the internal gear, so there is a problem in that the coaxiality and perpendicularity between the gear case housing and the internal gear in which the bearing is arranged with the required accuracy cannot be obtained. .

  The present invention solves the above-mentioned problems, and by constructing the gear case and the internal gear in an integral structure, there is no influence of accuracy deterioration or misalignment due to press-fitting, and high accuracy can be maintained and the internal gear diameter is increased. Therefore, it is an object of the present invention to provide a planetary reduction gear internal gear fixing method and a structure thereof, and a planetary reduction gear capable of designing a high-strength gear specification.

In order to solve the above-mentioned problems, the present invention is a method for fixing an internal gear and a gear case of a planetary speed reducer, wherein the gear case is cast on a die of the gear case on an annular outer peripheral surface made of alloy steel at the time of die casting. Inserts an internal gear blank in which a processed portion for preventing idling and slipping is inserted, and then the die case is die-cast to fix the internal gear blank to the gear case through the processed portion , The internal gear blank is subjected to gear machining to attach the internal gear to the gear case inner peripheral surface.
Further, the internal gear blank, a stepped portion is formed in the axial direction of the outer peripheral surface or inner peripheral surface, a thin portion of the stepped portion is exposed from the gear case end face, during the gear cutting and gear case processing It is to be used as a processing standard or an inlay joint.
Further, the internal gear blank is subjected to heat treatment such as quenching and tempering before being inserted into the mold of the gear case, and the temperature at which the internal gear blank is not tempered by the die-cast molten metal when the gear case is cast. And die casting the gear case over time.
Still further, it is a fixing structure for fixing the internal gear of the planetary reduction gear to the gear case, and when the gear case is cast by die casting, an inner peripheral surface of the alloy steel is formed with a processing portion for preventing slipping and slipping out . A gear blank is fixed to the inner surface of the gear case via the processing portion , and the inner peripheral surface of the internal gear blank fixed to the inner surface of the gear case is processed to form an internal gear.
Further, the internal gear blank is formed with a stepped portion in the axial direction of the outer peripheral surface or the inner peripheral surface, and is used as a processing reference or a spigot joint at the time of gear processing and gear case processing of the internal gear blank. The thin portion side of the stepped portion is fixed by protruding from the end face of the gear case.
A planetary speed reducer that decelerates the rotation of an electric motor by a planetary gear mechanism, the sun gear provided with an input unit to which the rotation of the electric motor is input, and the rotation of the sun gear and the rotation around the sun gear A planetary gear, an internal gear fixed to the gear case of the speed reducer and meshed with the planetary gear, and an output shaft for extracting rotation due to the revolving motion of the planetary gear . outer or form a stepped portion in the axial direction of the inner peripheral surface, and a processing unit for idling and strain relief provided on the outer peripheral surface, said internal gear blank at the time of gear case casting of the speed reducer, the The internal gear and the gear case are integrally fixed by performing gear processing and gear case processing after being fixed integrally to the gear case via the processing portion .

According to the present invention, the following effects can be obtained.
According to the first aspect, since the gear case and the internal gear have an integrated structure, there is no influence of accuracy deterioration or misalignment due to press-fitting, and high accuracy can be maintained.
Since the gear case and the internal gear have an integral structure, the diameter of the internal gear can be made large, so that it is possible to design a high-strength gear specification. Since the finishing lathe is performed after the gear case and the internal gear are integrated, the accuracy of the internal gear blank is not affected. Therefore, it is not necessary to strictly manage the accuracy of the internal gear blank as compared with the conventional method of fixing two parts.
According to the second aspect of the present invention , the stepped small-diameter portion of the internal gear blank is exposed, so that it can be used as a reference for processing or an inlay at the time of assembly.
According to the third aspect of the present invention , the mass at the time of the heat treatment is reduced as compared with the integrated structure obtained by cutting from the conventional alloy steel, so that the quality of the heat treatment is improved.
According to the fourth aspect of the present invention, the finishing lathe process is performed after the internal gear and the gear case are integrated, and the internal gear is processed in the final process. It becomes possible to maintain the accuracy.
In addition, the amount of cutting can be greatly reduced in machining, and the square shape and mounting holes can be configured with molds, simplifying the machining process, and most of the parts to be cut are made of aluminum alloy, so hard materials can be cut. This eliminates the increase in tool wear and machining time due to, resulting in a reduction in machining costs.
Furthermore, since the material of the part which becomes an external appearance becomes an aluminum alloy, the influence of rust is reduced compared with alloy steel, and the rust prevention processing cost can also be reduced.
Thus, the manufacturing cost can be reduced.
According to the fifth aspect , since the small diameter portion of the stepped shape of the internal gear blank is exposed, it can be used as a reference for processing and an inlay at the time of assembly.
According to the sixth aspect of the present invention, the finishing lathe is processed after the internal gear and the gear case are integrated, and the internal gear is processed in the final process. It becomes possible to maintain the accuracy.

It is a longitudinal cross-sectional view of the planetary reduction gear which shows the internal gear fixed structure of the planetary reduction gear by embodiment of this invention. It is a longitudinal section showing an integrated internal gear and gear case by an embodiment of the invention. It is a side view which shows the internal gear blank by embodiment of this invention. It is sectional drawing which shows the die-casting die used for the fixing method which integrates an internal gear and a gear case. It is sectional drawing which shows fixation of an internal gearwheel, and a die-casting method. It is sectional drawing which shows the attachment method of an internal gear blank. (A) (b) (c) (d) (e) is a conceptual diagram at the time of employ | adopting methods other than an eyelet knurling for the internal gear blank by embodiment of this invention. It is a figure of the conventional internal gear and a gear case. It is a figure of the conventional internal gear and a gear case.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a sectional view of a planetary speed reducer using an integrated internal gear and gear case of the present invention.
Reference numeral 1 denotes a planetary speed reducer. The planetary speed reducer 1 is assembled to a motor 2 and decelerates the rotation of the motor 2 by a planetary gear mechanism.
The case of the planetary reduction gear 1 is composed of a gear case 10, an intermediate gear case 11, and a gear flange 12 each having a hollow interior. The gear case 10 is formed by die casting using aluminum as a raw material, and the intermediate gear case 11 and the gear flange 12 can also be formed by die casting. The gear case 10 and the intermediate gear case 11 are provided with flange portions 10a and 11a each having a screw hole 13a on the outer peripheral surface. The flange portions 10a and 11a are aligned with each other and fastened to each other by a screw 13. The intermediate gear case 11 and the gear flange 12 are fastened to each other by a so-called stamped joint. It is concluded.

As shown in FIG. 2, an internal gear 15 made of alloy steel is integrally provided on the inner surface of the gear case 10. As shown in FIG. 3, the internal gear 15 is provided with a small-diameter portion 15 a having a stepped shape, which is a thin-walled portion, and the thin-walled portion of the small-diameter portion 15 a is provided inside the intermediate gear case 11. And are fastened to each other by a seal joint. On the outer peripheral surface of the large-diameter portion 15b that is a thick-walled portion of the internal gear 15, a processed portion 15c that has been subjected to processing such as knurling is provided.
As shown in FIG. 1, one or a plurality of planetary gears 16 are engaged with the internal gear 15, and these planetary gears 16 are rotatable on a planetary shaft 18 provided on a support carrier 17 via a bearing 19. It is supported by. The support carrier 17 has a ring shape supported on the inner surface of the intermediate gear case 11 via a bearing 20, and a sun gear 21 serving as an input shaft is inserted on the axis thereof. The planetary gear 16 meshes with the sun gear 21 and revolves around the sun gear 21.

On the same axis as the sun gear 21, an output carrier 22 serving as an output shaft is disposed in the gear case 10 so as to face the support carrier 17, and the output carrier 22 and the support carrier 17 are arranged in the circumferential direction. A plurality of screws 23 are fixed. The support carrier 17 is provided with a spacer portion 17a that keeps a distance from the output carrier 22 in the axial direction, and a screw hole 23a through which the screw 23 is inserted is provided in the spacer portion 17a along the axial direction. It has been. Between the support carrier 17 and the output carrier 22, a plurality of the planetary gears 16 having a width shorter than the length of the spacer portion 17a are arranged.
The output carrier 22 is rotatably supported via a bearing 24 disposed on the inner surface of the gear case 10, and the planetary shaft 18 is fixed to the output carrier 22 in the axial direction. The output carrier 22 is rotationally driven as the planetary shaft 18 rotates, and takes out the revolution movement of the planetary gear 16 as an output.

  The sun gear 21 has a large-diameter portion 21a at a base end portion rotatably supported via a bearing 25 provided on the inner surface of the intermediate gear case 11, and the large-diameter portion 21a is opposite to the sun gear 21. Further, a coupling 26 connected to the output shaft 2a of the motor 2 is provided.

  In the operation of the planetary gear mechanism, rotation output from the output shaft 2 a of the motor 2 is transmitted to the sun gear 21 through the coupling 26. The rotation of the sun gear 21 is transmitted to the planetary gear 16 to rotate the planetary gear 16 and to rotate the planetary gear 16 along the internal gear 15. The planetary gear 16 revolves along the internal gear 15 while rotating around the planetary shaft 18. Thus, the rotation of the planetary shaft 18 that revolves with the planetary gear 16 is transmitted to the output carrier 22, and is transmitted from the output shaft 22a of the output carrier 22 to the outside to transmit the rotational power.

Next, a method for fixing the alloy steel internal gear 15 to the inner surface of the gear case 10 will be described.
FIGS. 4 and 5 show a mold 30 for performing die casting of the gear case 10. The mold 30 includes a fixed mold 31 and a movable mold 32. In the fixed die 31, a nest 31 </ b> B is disposed in a hollow portion of the main die 31 </ b> A, and an insert 31 </ b> C is biased via a spring 33 inside the nest 31 </ b> B. The insert 31C is provided with a cooling device 34 for cooling the insert 31C and moving it smoothly.
On the other hand, in the movable mold 32, a nest 32B is disposed in the cavity of the main mold 32A, and a cavity 35 for casting the gear case 10 is formed in the nest 32B. A movable core 36 assembled with the internal tooth blank 15A is disposed inside the insert 32B. As shown in FIG. 6, the movable core 36 is provided with a draft angle 36 </ b> A in the axial direction of the outer peripheral surface. The movable core 36 is provided with a cooling device 37 in order to smoothly solidify and take out the aluminum alloy of the gear case 10.
FIG. 5 shows a gate 38 and a runner 39 for injecting a molten aluminum alloy into the cavity 35 of the mold 30, and the molten metal is poured from the gate 38 into the cavity 35 through the runner 39.

  In the operation of the mold 30, the internal tooth blank 15 </ b> A is set in advance on the outer peripheral surface of the movable core 36, and the internal tooth blank 15 </ b> A is disposed on the inner surface of the cavity 35 of the movable mold 32. Next, the movable mold 32 is operated and combined with the fixed mold 31. The insert 31 </ b> C provided in the fixed die 31 abuts against the end surface of the internal tooth blank 15 </ b> A by the urging force of the spring 33 to restrict the movement of the internal tooth blank 15 </ b> A. Thus, the internal tooth blank 15 </ b> A is arranged in the cavity 35 in the mold 30. Next, casting is performed by pouring a molten metal such as an aluminum alloy from the gate 38 into the cavity 35 through the runner 39. When the casting is finished, the movable mold 32 is operated to take out the gear case 10 that is separated from the fixed mold 31 and molded integrally with the internal tooth blank 15A. Next, gear processing is performed on the inner peripheral surface of the internal tooth blank 15 </ b> A to form the internal gear 15.

Next, a specific embodiment for fixing the internal gear blank 15A to the gear case 10 will be described.
The internal gear 15 is turned on an alloy steel such as an SCM material to form a stepped ring shape, and an outer knurled process is performed on the outer peripheral surface of the stepped large diameter portion 15b to prevent slipping and slipping. Since finishing lathe processing is performed in a later process, the internal gear blank 15A does not require strict accuracy at this stage. Thereafter, a quenching and tempering process is performed to obtain a required hardness for the internal gear 15.

  The internal gear blank 15 </ b> A is heated to about 870 ° C., and then quenched by oil cooling at about 70 ° C. After quenching, the internal gear blank 15A is given a viscosity and tempered at about 580 ° C. in order to adjust the hardness to the required hardness. In the quenching and tempering of the internal gear blank 15A in this case, it is most important to obtain the necessary hardness up to the inside of the material that is the part that will eventually become the gear. For that purpose, it is important to obtain a critical cooling rate to the inside of the material when quenching.

In the conventional method of realizing an integrated structure by cutting out from alloy steel, the mass of the material is large, and it is difficult to obtain a critical cooling rate to the inside of the material. However, the internal gear blank 15A of the present invention is compared with the conventional one. Since the mass of the material becomes small, a critical cooling rate can be easily obtained up to the inside of the material, and the quality of heat treatment can be improved.
Conditions such as the material of the internal gear blank 15A, the temperature of quenching and tempering, etc. may be changed as necessary.
Moreover, you may select heat processing other than hardening and tempering as needed. The internal gear blank 15A manufactured as described above is inserted when the gear case 10 is cast by aluminum die casting.

  Then, the internal gear blank 15A is set in the mold, and a molten aluminum alloy at about 690 ° C. is poured into the mold and pushed in at a casting pressure of about 80 Mpa for about 0.04 seconds. This casting condition may be changed as necessary. When heat treatment such as quenching and tempering is performed on the internal gear blank 15A, the inner gear blank 15A is exposed to aluminum alloy hot water at a temperature close to the tempering temperature, so that the hardness changes due to the same effect as tempering. However, there is no effect because the casting process is short. Since the square shape and mounting holes necessary for the gear case 10 are configured by a mold, there is no need for processing. Thereafter, a lathe finishing process is performed on the internal gear blank 15A and the gear case 10 integrated by casting.

As a result, the internal gear blank 15A and the gear case 10 can be simultaneously processed based on the same processing standard, and the coaxiality and perpendicularity between the gear case housing in which the bearing is arranged and the internal gear 15 can be maintained with high accuracy. It becomes.
The stepped small diameter portion 15a of the internal gear blank is exposed at the time of casting, or is exposed in a subsequent lathe finishing process. As a result, it can be used as a reference for processing and an inlay for assembly.
Thereafter, the internal gear machining is performed based on the stepped small diameter portion 15a of the internal gear blank 15A in the final step. It is possible to use it in a planetary speed reducer with the best gear accuracy by machining the internal gear according to the final process and the machining standard with which the coaxiality and squareness with the housing of the gear case 20 are obtained. It is.

FIG. 7 shows a modified example of the internal gear blank 15A. The idle knurling for preventing idling and slipping out of the internal gear blank 15A is performed in accordance with the safety factor with respect to the actual use load, flat knurling, groove processing, male screw processing, It is possible to reduce the processing cost or improve the strength by changing the spline processing or not performing the processing. 7 (a), (b), (c), (d), and (e) are respectively flat knurled (FIG. 7 (a)), groove machining (FIG. 7 (b)), and male thread machining (FIG. 7). (C)), spline machining (FIG. 7 (d)), and a view showing an internal gear blank 15A when machining is not performed (FIG. 7 (e)).
In the above, the outer diameter of the internal gear blank is a stepped shape, but the inner diameter may be a stepped shape.
In that case, the outer diameter is knurled, gear processing is performed on the small diameter portion of the inner diameter, and the large diameter portion of the inner diameter is used as a machining reference or inlay.

According to the above embodiment, the following effects can be obtained.
Since the gear case 10 and the internal gear 15 have an integral structure, the accuracy deterioration due to the press-fitting of the internal gear and the influence of misalignment are eliminated, and high accuracy can be maintained.
Since the gear case 10 and the internal gear 15 have an integral structure, the diameter of the internal gear 15 can be increased, so that it is possible to design a high-strength gear specification.
Since the finishing lathe is performed after the gear case 10 and the internal gear 15 are integrated, the accuracy of the internal gear blank 15A is not affected.
Therefore, it is not necessary to strictly manage the accuracy of the internal gear blank 15A as compared with the conventional method of fixing two parts.
Compared with the conventional integrated structure by cutting out from alloy steel, the mass during the heat treatment is reduced, so the quality of the heat treatment is improved. In addition, the amount of cutting can be greatly reduced in machining, and the square shape and mounting holes can be configured with a mold, so the machining process can be simplified. This eliminates the increase in tool wear and machining time due to, resulting in a reduction in machining costs. Furthermore, since the material of the part which becomes an external appearance becomes an aluminum alloy, the influence of rust is reduced compared with alloy steel, and the rust prevention processing cost can be reduced. Thus, the manufacturing cost can be reduced.
A high fixing force can be maintained by performing knurling on the large-diameter portion 15b of the stepped shape of the internal gear blank 15A.
Since the step-shaped small-diameter portion 15a of the internal gear blank 15A is exposed, it can be used as a reference for processing or an inlay at the time of assembly. Further, since the finishing lathe is processed after the internal gear blank 15A and the gear case 10 are integrated and the internal gear is processed in the final process, the coaxiality and perpendicularity between the housing of the gear case 10 in which the bearings are arranged and the internal gear 15 are increased. It becomes possible to maintain the accuracy.

  Note that the present invention is not limited only to the above-described embodiment. For example, the internal gear blank 15A does not require accuracy, so that it is not limited to the stepped shape, and various shapes can be used. it can. Moreover, since the inner diameter can be increased by using a thin inner gear blank 15A, the reduction gear can be reduced in size. Needless to say, the present invention can be appropriately modified and modified without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Planetary reduction gear 2 Motor 10 Gear case 11 Intermediate gear case 12 Gear flange 15 Internal gear 15a Small diameter part 15b Large diameter part 15c Processing part 16 Planetary gear 17 Support carrier 17a Spacer part 18 Planetary axis 21 Sun gear 21a Large diameter part 22 Output carrier 22a Output Shaft 26 coupling

Claims (6)

A method for fixing an internal gear and a gear case of a planetary reducer,
At the time of die casting of the gear case, the gear case is die-casted after inserting an internal gear blank in which an annular outer peripheral surface made of alloy steel is formed with a machined portion for preventing idling and slipping out into the mold of the gear case. The internal gear blank is fixed to the gear case through the processing portion , and then the internal gear blank is subjected to gear processing to attach the internal gear to the gear case inner peripheral surface. To fix the internal gear of the planetary speed reducer. The internal gear blank is formed with a stepped portion in the axial direction of the outer peripheral surface or the inner peripheral surface, and the thin portion side of the stepped portion is exposed from the end surface of the gear case , so that a processing standard for gear processing and gear case processing The planetary reduction gear internal gear fixing method according to claim 1 , wherein the planetary reduction gear is used as an inlay joint. The internal gear blank is subjected to heat treatment such as quenching and tempering before being inserted into the mold of the gear case, and a temperature and time at which the internal gear blank is not tempered by the die-cast molten metal when the gear case is cast. The method for fixing an internal gear of a planetary reduction gear according to claim 1 or 2 , wherein the gear case is die-cast. A fixed structure for fixing the internal gear of the planetary reduction gear to the gear case,
At the time of die casting of the gear case, an inner gear blank having an annular outer peripheral surface made of alloy steel formed with a processed portion for preventing slipping and slipping is fixed to the inner surface of the gear case via the processed portion , and the inner surface of the gear case is fixed. An internal gear fixing structure for a planetary speed reducer, wherein an internal gear is formed by subjecting an inner peripheral surface of an internal gear blank fixed to the inner surface to gear processing. The internal gear blank is formed with a stepped portion in the axial direction of the outer peripheral surface or the inner peripheral surface, and the stepped portion is used as a processing standard or a spigot joint when processing the gear of the internal gear blank and gear case processing. The planetary reduction gear internal gear fixing structure according to claim 4 , wherein the thin-walled portion side of the portion protrudes from the end face of the gear case and is fixed. A planetary speed reducer that decelerates rotation of an electric motor by a planetary gear mechanism,
A sun gear provided with an input unit for inputting rotation of the electric motor; a planetary gear that transmits the rotation of the sun gear and rotates around the sun gear; and the planetary gear fixed to a gear case of the speed reducer. The inner gear and the output shaft for extracting the rotation by the revolving motion of the planetary gear, and forming a stepped portion in the axial direction of the outer peripheral surface or the inner peripheral surface in the internal gear blank before gear processing , and a processing unit for idling and strain relief provided on the outer peripheral surface, said internal gear blank at the time of gear case casting of the reduction gear, through the processing unit, gear cutting and after integrally fixed to the gear case A planetary speed reducer characterized in that a gear case is processed and the internal gear and the gear case are fixed integrally.

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