JP2015113916A - Eccentric oscillation type speed reducer and method of manufacturing eccentric body shaft gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an eccentric body shaft gear of an eccentric oscillation type speed reducer that can make finishing costs (while maintaining predetermined quality).SOLUTION: There is provided a method of manufacturing an eccentric body shaft gear of an eccentric oscillation type speed reducer 10 which includes an eccentric body shaft 18 having first and second eccentric bodies 20 and 22, and an eccentric body gear 30 for rotating the eccentric body shaft, the eccentric shaft gear having a fitting hole 30P, in which a gear fitting part 70 provided for the eccentric body shaft is fitted, at its radially center part. The method include: a process A of forming a tooth part 30T at an outer periphery of a raw material of the eccentric body shaft gear; a process B of forming the fitting hole in the radial center of the raw material of the eccentric body shaft gear; and a process C3 of subjecting the tooth part to high-frequency hardening to make tooth surfaces higher in hardness than an inner peripheral surface of the fitting hole.

Description

  The present invention relates to an eccentric oscillation type speed reducer and a method for manufacturing the eccentric body shaft gear.

  Patent Document 1 discloses an eccentric rocking type speed reducer.

  In this reduction gear, the external gear is in mesh with the internal gear while swinging. And the relative rotation which arises depending on the number-of-teeth difference of an external gear and an internal gear is taken out as a deceleration output.

  In order to oscillate the external gear, this speed reduction device includes three eccentric body shafts provided with eccentric bodies and eccentric body shaft gears for rotating the eccentric body shafts. Each eccentric body shaft gear has a fitting hole that fits in a gear fitting portion provided on the eccentric body shaft in the central portion in the radial direction.

  In Patent Document 1, the fitting hole of the eccentric shaft gear is formed in a polygon (not a spline). According to the disclosure in Patent Document 1, this replaces the finishing process of the fitting hole of the eccentric shaft gear with the finishing process by a relatively low cost cam grinder instead of the finishing process by the high-cost hard broach. It is said that you can.

JP2013-96550A ([0006] to [0010])

  However, the finishing process of the eccentric shaft gear is still expensive, and the development of an eccentric shaft gear that can further reduce the cost of the finishing process has been demanded.

  The present invention has been made in view of such circumstances, and the eccentric shaft gear of the eccentric oscillating speed reduction device capable of further reducing the cost of finishing (while maintaining a predetermined quality). The challenge is to obtain.

  The present invention includes an eccentric body shaft provided with an eccentric body and an eccentric body shaft gear for rotating the eccentric body shaft, and the eccentric body shaft gear is provided on the eccentric body shaft at a radial center portion. A method of manufacturing the eccentric shaft gear of an eccentric oscillating speed reducer having a fitting hole that fits into the gear fitting portion, wherein a tooth is provided on the outer periphery of the material of the eccentric shaft gear. A step of forming a fitting portion, a step of forming the fitting hole in the radial center of the material of the eccentric body gear, and induction hardening of the tooth portion, and the hardness of the tooth surface of the fitting hole The above-described problem is solved by including a step of making the hardness higher than the hardness of the inner peripheral surface.

  According to the present invention, after undergoing the step of forming the tooth portion and the fitting hole in the eccentric body shaft gear, the tooth portion is subjected to induction hardening, and the hardness of the tooth surface is higher than the hardness of the inner peripheral surface of the fitting hole. (The hardness of the inner peripheral surface of the fitting hole is made lower than the hardness of the tooth surface).

  As a result, heat treatment distortion does not occur in the vicinity of the fitting hole (while maintaining the hardness of the tooth portion), so that the finishing process itself of the fitting hole can be omitted or the finishing process can be performed. Even if it does, it will be sufficient to finish with a small (simple) machining allowance, the processing time can be shortened, and the cost of finishing can be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the eccentric body shaft gear of the eccentric rocking | fluctuation type reduction gear which can further reduce finishing cost (while maintaining predetermined quality) can be obtained.

1 is an overall cross-sectional view of an eccentric oscillating speed reduction device to which a manufacturing method according to an example of an embodiment of the present invention is applied. The schematic diagram which shows the meshing state of the input gear and eccentric body shaft gear of the said reduction gear, and the fitting relationship of an eccentric body shaft gear and an eccentric body shaft The diagram which shows the temperature setting in the finishing process of the eccentric body shaft gear of the said reduction gear

  Hereinafter, an example of an embodiment of the present invention will be described in detail based on the drawings.

  FIG. 1 is an overall cross-sectional view of an eccentric oscillation type reduction gear to which a manufacturing method according to an example of an embodiment of the present invention is applied, and FIG. It is a schematic diagram which shows the fitting relationship between the eccentric body shaft gear and the eccentric body shaft. First, the overall configuration of the reduction gear will be described.

  The speed reducer 10 is an eccentric oscillating type speed reducer called a so-called sort type. The reduction gear device 10 includes an internal gear 12 and first and second external gears 14 and 16 that are in mesh with the internal gear 12, and only the axis O1 to R1 of the internal gear 12 is provided. A plurality of (three in this example) eccentric shafts 18 (18A to 18C: only 18A is shown in FIG. 1) for swinging the first and second external gears 14 and 16 are provided at the offset positions. Yes.

  In the reduction gear device 10 according to this embodiment, the power of a motor (not shown) is input via the input shaft 26. An input gear 32 is directly cut and formed at the end of the input shaft 26 on the side opposite to the motor.

  The input gear 32 meshes simultaneously with a plurality of (in this example, three) eccentric body shaft gears 30 (30A to 30C: see FIG. 2, only 30A is shown in FIG. 1). Each eccentric body shaft gear 30 is connected to the eccentric body shaft 18 via its own fitting hole 30P (30Ap to 30Cp) and the gear fitting portion 70 (70A to 70C) of the eccentric body shaft 18, respectively. In this embodiment, the shape of the fitting hole 30P of the eccentric body shaft gear 30 and the gear fitting portion 70 of the eccentric body shaft 18 is a polygonal shape in which the cross section perpendicular to the axial direction of the eccentric body shaft 18 is a regular hexagon. Has been. The configuration in the vicinity of the eccentric body shaft 18 and the eccentric body shaft gear 30 will be described in detail later.

  The three eccentric body shafts 18 are arranged at intervals of 120 degrees in the circumferential direction on the circumference offset from the axis O1 of the internal gear 12 by R1. Each eccentric shaft 18 has a first eccentric body 20 formed at the same position in the axial direction, and a second eccentric body 22 formed adjacent to the first eccentric body 20 at the same position in the axial direction. Yes. The first eccentric bodies 20 and the second eccentric bodies 22 of the eccentric body shafts 18 have the same eccentric phase. The eccentric phase difference between the first eccentric body 20 and the second eccentric body 22 is 180 degrees (eccentric in a direction away from each other).

  The first external gear 14 is incorporated on the outer periphery of the first eccentric body 20 of each eccentric body shaft 18 via a first eccentric body bearing 34 formed of rollers. The second external gear 16 is incorporated on the outer periphery of the second eccentric body 22 of each eccentric body shaft 18 via a second eccentric body bearing 36 formed of rollers. As a result, the first eccentric body 20 on the three eccentric body shafts 18 rotates in synchronization with each other, thereby swinging the first external gear 14, and similarly, the second eccentric gear shaft 18 on the three eccentric body shafts 18. The second external gear 16 can be swung by the eccentric body 22 rotating synchronously. The eccentric phase difference between the first external gear 14 and the second external gear 16 is 180 degrees (in response to the eccentric phase difference between the first eccentric body 20 and the second eccentric body 22).

  First and second carriers 38 and 40 are disposed on both sides in the axial direction of the first and second external gears 14 and 16, and the eccentric body shafts 18 are respectively connected to the first and second bearing arrangement portions 19 and 19, respectively. 21, the first and second carriers 38 and 40 are supported by first and second eccentric shaft bearings 44 and 46 (bearings that support the eccentric shaft 18) configured by a pair of tapered roller bearings. Yes. The first and second carriers 38 and 40 are supported by the casing 52 via a pair of angular ball bearings 48 and 50. The first and second carriers 38 and 40 protrude integrally from the first carrier 38 and are connected by bolts 53 and the like via carrier pins 38P passing through the first and second external gears 14 and 16. It is integrated.

  The first and second external gears 14 and 16 are in mesh with the internal gear 12. In this embodiment, the internal gear 12 is an internal gear main body 12A integrated with the casing 52, and an external pin that is rotatably incorporated in the internal gear main body 12A and constitutes internal teeth of the internal gear 12. 12B. The number of teeth of the internal gear 12 (the number of external pins 12B) is slightly larger (only 1 in this example) than the number of teeth of the first and second external gears 14 and 16.

  In the present embodiment, a first arm (not shown) of the robot is connected to the casing 52 via a bolt (only the bolt hole 52A is shown), and the first carrier 38 is connected via a bolt (only the tap hole 38B is shown). The second arms (not shown) of the robot are connected to each other. Reference numeral 61 denotes an oil seal.

  Next, the operation of the eccentric oscillating speed reduction device 10 will be described.

  When a motor (not shown) rotates, the input gear 32 formed at the tip of the input shaft 26 rotates. Since the input gear 32 is meshed with the three eccentric body shaft gears 30 simultaneously, the three eccentric body shaft gears 30 are rotated in the same direction and at the same rotational speed by the rotation of the input gear 32. To do.

  Each eccentric body shaft gear 30 is connected to the eccentric body shaft 18 via the fitting hole 30P of the eccentric body shaft gear 30 and the fitting of the gear fitting portion 70 of the eccentric body shaft 18 respectively. Therefore, the three eccentric body shafts 18 are synchronously rotated at the same rotational speed in the same direction in a state where the gear ratio of the input gear 32 and the eccentric body shaft gear 30 is reduced. As a result, the three first eccentric bodies 20 formed at the same position in the axial direction of each eccentric body shaft 18 rotate synchronously to swing the first external gear 14 and each eccentric body shaft 18. The three second eccentric bodies 22 respectively formed at the same position in the axial direction rotate in synchronization with each other to swing the second external gear 16.

  Since the first and second external gears 14 and 16 are internally meshed with the internal gear 12, each time the first and second external gears 14 and 16 swing once, the first The second external gears 14 and 16 are out of phase (rotated) in the circumferential direction with respect to the internal gear 12 by a difference in the number of teeth (one tooth in this embodiment). This rotation component is transmitted to the first and second carriers 38 and 40 as revolutions around the axis O1 of the internal gear 12 of each eccentric body shaft 18. Since the first and second carriers 38 and 40 are connected to each other via a carrier pin 38P and a bolt 53 integrated with the first carrier 38, the first and second carriers 38 and 40 are eventually connected to the casing 52 by the rotation of the input shaft 26. The second arm connected to the first carrier 38 can be rotated relative to the first arm.

  Here, referring to FIG. 2 and FIG. 3 together, the configuration around the eccentric body shaft gear 30 will be described in detail together with the method of manufacturing the eccentric body shaft gear 30.

  In this type of eccentric oscillating speed reduction device 10, it is essential to stably rotate the eccentric body shaft 18 in order to stably oscillate the first and second external gears 14 and 16. Is a requirement. In particular, as in this embodiment, a so-called sorting type (internal gear and an external gear internally engaged with the internal gear, and a position offset by a predetermined amount from the axis of the internal gear) In addition, in the eccentric oscillating speed reduction device 10 of a type including a plurality of eccentric body shafts for oscillating the external gear, the phase characteristics of the eccentric body shafts 18 are also accurately aligned. There is a need. Therefore, conventionally, the eccentric body shaft gear 30 for rotating the eccentric body shaft 18 needs to have sufficient hardness, and the tooth portion 30T and the fitting hole 30P need high-precision finishing. It was supposed to be.

  For this reason, conventionally, the material of the eccentric shaft gear (30) includes a step of forming a tooth portion (30T) on the outer periphery of the material and a step of forming a fitting hole (30P) in the radial center of the material. After passing through, the whole eccentric gear shaft gear (30) was subjected to heat treatment by carburizing and quenching to give sufficient hardness to the whole material.

  However, heat treatment by carburizing and quenching inevitably increases heat treatment strain, making it difficult to ensure high dimensional accuracy. In other words, the finishing process of the fitting hole of the eccentric shaft gear, including the technology disclosed in Patent Document 1 described above, is such that “the material of the eccentric shaft gear requires a sufficient hardness. Against the backdrop of the fact that carburizing / quenching heat treatment is indispensable, and the fact that, when carburizing / quenching heat treatment is performed, large heat treatment distortion is generated, and finishing processing is indispensable to correct it. It can also be said that it has been performed.

  In the present embodiment, however, this situation is reversed, and the “tooth portion 30T” of the eccentric shaft gear 30 is subjected to induction hardening, and the hardness of the tooth portion 30T (more specifically, the tooth surface) is fitted. It is configured to include a step of making it higher than the hardness of the periphery of the hole 30P (more specifically, the inner peripheral surface of the fitting hole 30P). In other words, in this configuration, the periphery of the fitting hole 30P of the eccentric body shaft gear 30 according to the present embodiment is lower in hardness (softer) than the tooth portion 30T, and the eccentric body shaft as in the prior art. Compared to the case where the entire gear is carburized and quenched, the heat treatment distortion is small.

  Therefore, by adopting this manufacturing method, the eccentric body shaft gear 30 according to the present embodiment can omit the finishing process itself of the fitting hole 30P depending on conditions. Even when finishing is performed, since the heat treatment distortion is small, the “cutting allowance” in the finishing is small. Therefore, the finishing process itself is simple, the processing time can be shortened, and as a result, the cost of the finishing process of the fitting hole 30P can be reduced.

  In addition, since the hardness of the material is not high around the fitting hole 30P, an expensive hard broach is, of course, unnecessary as a processing machine, and even processing by a cam grinding machine at a lower cost is unnecessary. Further, it is considered that there are more scenes where it is possible to adopt a normal broach finishing process (broach finishing process performed on a material having a Rockwell hardness of HRC 50 or less) at a lower cost. That is, the cost of the processing machine can be further reduced.

  Further, since the hardness of the periphery of the fitting hole 30P is low (partially soft) with respect to the hardness of the tooth portion 30T, the teeth are engaged by the engagement of the input gear (drive source side gear) 32 and the eccentric shaft gear 30. The eccentric body shaft 18 can be rotated while satisfactorily absorbing part of vibration and noise generated in the vicinity of the portion 30T (vibration and noise reduction effect). In addition, since there is a difference in hardness, the phenomenon that the eccentric shaft gear 30 as a whole resonates can be avoided, and in this respect, an effect of suppressing an increase in vibration and noise can be obtained.

  Therefore, while maintaining the hardness of the tooth portion 30T of the eccentric body shaft gear 30 to be high, as a result, it is possible to obtain the eccentric oscillating speed reduction device 10 with lower vibration and lower noise. As a result, the effects of low vibration and lower noise can be obtained particularly conspicuously when the speed reducer 10 is a distributed type eccentric oscillating speed reducer as described above.

  In the present embodiment, the hardness difference between the tooth portion 30T of the eccentric body shaft gear 30 and the periphery of the fitting hole 30P is obtained by performing induction hardening on the tooth portion 30T. The phenomenon that the periphery of the fitting hole 30P becomes hard to some extent due to the influence of induction hardening on the tooth portion 30T is allowed. In short, it is sufficient that the hardness of the tooth portion 30T can be maintained at a Rockwell hardness HRC, for example, 10 points or more higher than the hardness around the fitting hole 30P by induction hardening of the tooth portion 30T. That is, as a result, a hardness difference of 10 points or more is required in the hardness difference, for example, Rockwell hardness HRC, between the tooth portion 30T and the periphery of the fitting hole 30P. The specific process of how to obtain this hardness difference is not particularly limited except for the process of “high-frequency quenching of teeth”.

  For example, depending on the specification and application of the eccentric body shaft gear, the entire eccentric body shaft gear including the periphery of the fitting hole may be carburized. However, in this case, if the “quenching process”, which is conventionally performed after the carburizing process, is performed, it becomes impossible to obtain a hardness difference between the teeth and the periphery of the fitting hole. In other words, after the carburizing process, the “quenching process” should not be performed, but “furnace cooling (slow cooling in the carburized furnace)” should be performed.

  A specific heat treatment process example is shown in FIG.

  In the process example shown in FIG. 3, after passing through the process A which forms the tooth part 30T in the outer periphery of the raw material of the eccentric body shaft gear 30, and the process B which forms the fitting hole 30P in the radial direction center of the raw material, the eccentric body The entire shaft gear 30 is carburized (step C1). Then, after slow cooling in a carburized furnace (step C2), the induction hardening is performed on the tooth portion 30T (step C3). Thereafter, a tempering process is performed (step C4).

  As a forming method of the tooth portion 30T in the process A, a known forming method can be appropriately adopted, but in the present embodiment, for example, it is formed by hobbing.

  As a forming method of the fitting hole 30P in the process B, a known forming method can be adopted as appropriate, but in the present embodiment, for example, it is formed by broaching. Note that the order of performing the process A and the process B may be reversed.

  In the carburizing process of the process C1, the material of the eccentric shaft gear 30 in which the tooth portion 30T and the fitting hole 30P are formed is placed in a carburizing furnace and heated in an atmosphere of a gas containing carbon (time t1 to t2). ), Maintaining a high temperature state (time t2 to t3). In the present embodiment, for example, the temperature is held at about 800 ° C. to 1000 ° C. for about 150 minutes to 450 minutes. The holding temperature and holding time are not particularly limited, and may be set as appropriate according to the size of the material of the eccentric body shaft gear 30 and the required carburizing depth. In this embodiment, after that, the temperature is slightly lowered and held for a predetermined time (time t3 to t5). However, the processing at the time t3 to t5 may not be performed. By the above processing, carbon is included in the surface layer portion of the material of the eccentric body gear 30.

  By this carburizing treatment, carbon can be diffused on the surface of the material up to a carbon concentration capable of forming a martensite structure. That is, when quenching is performed, the composition of the material can be martensite, but in this embodiment, after the carburizing treatment, furnace cooling (slow cooling) is performed (step C2: times t5 to t6). That is, here, the furnace is daringly cooled to avoid the martensitic structure of the eccentric body shaft gear 30.

  In the furnace cooling in step C2, the material of the eccentric body shaft gear 30 is kept in the furnace even after the heating of the carburizing furnace is finished, and the cooling is performed slowly in accordance with the cooling rate of the furnace. The cooling rate of the furnace cooling is not particularly limited as long as it is a cooling rate that avoids the martensite formation of the structure, and is usually 30 ° C. to 100 ° C./hour. In this embodiment, the furnace is cooled in the carburized furnace. However, the present invention is not limited to this, and avoids martensite of the structure or at a rate slower than 100 ° C./hour. If it is cooled, it may be cooled by other than a carburizing furnace.

  Next, the material of the eccentric shaft gear 30 that has undergone furnace cooling is taken out from the carburizing furnace, and in step C3, induction hardening is performed only on the tooth portion 30T. Specifically, electromagnetic induction by high-frequency electromagnetic waves is caused in the tooth portion 30T, the surface is heated (time t11 to t12), and the state is maintained (time t12 to t13). The holding temperature and holding time are not particularly limited, and may be set as appropriate according to the size of the material of the eccentric shaft gear, the required hardness, the required curing depth, and the like. In the present embodiment, for example, the heating is performed at a temperature slightly lower than that during carburizing. Thereafter, quenching and quenching are performed (in this embodiment, quenching with water: times t13 to t14). By the above process, the surface layer structure of the tooth portion 30T is martensiticized.

  Next, tempering is performed in step C4 (time t21 to t24). Although the tempering temperature is not particularly limited, in the present embodiment, for example, it is about 150 ° C. to 300 ° C.

  When the furnace is cooled (slowly cooled), the carbon diffuses into the interior and the carbon concentration tends to decrease or the crystal becomes large. Therefore, the hardness around the fitting hole 30P is unlikely to increase. On the other hand, the surface layer structure of the tooth portion 30T can be martensite by induction hardening. Thereby, compared with the case where induction hardening is performed on the tooth part 30T without carburizing treatment, the hardness of the tooth part 30T can be further increased without increasing the thermal strain around the fitting hole 30P.

  As described above, this carburizing process (step C1) is not necessarily performed. When the carburizing process is not performed on the material of the eccentric body shaft gear 30, the process A in FIG. 3 for forming the tooth portion 30T on the outer periphery of the material of the eccentric body shaft gear 30 and the fitting hole in the radial center of the material After Step B for forming 30P, Step C3 is performed directly (omitting Steps C1 and C2). Depending on the application, or depending on the carbon concentration originally contained in the material, this may be sufficient for practical use.

  Further, as already described, the finishing process itself may be omitted for the fitting hole. That is, after induction hardening, for example, a finishing process (for example, a grinding process) for removing the heat treatment strain may be performed only on the tooth portion. Of course, the finishing of the fitting hole may be performed. Even in the case of finishing, since the heat treatment strain is small around the fitting hole, the “cutting allowance” in the finishing is small, the finishing itself is simple, and the processing time can be shortened. In addition, it is considered that the usual (low-cost) broach finishing process performed on a material having a Rockwell hardness of HRC50 or less, for example, can be performed (because the hardness of the inner peripheral surface of the fitting hole is low). .

  However, since the heat treatment distortion due to induction hardening occurs in the tooth portion, the finishing process is not omitted in order to ensure the dimensional accuracy required for the eccentric body shaft gear of this type of eccentric oscillating speed reducer. Is preferred. In particular, as in the above heat treatment example, when the materials of the eccentric body shaft gear are subjected to carburizing treatment, gradually cooled in the furnace, and then subjected to induction quenching on the tooth portion, etc. In such a case, the heat treatment strain at the tooth portion tends to be larger, and finishing should be performed.

  The shape of the fitting hole of the eccentric body shaft gear and the gear fitting portion of the eccentric body shaft was a polygonal shape having a regular hexagonal cross section perpendicular to the shaft in the above embodiment. The shapes of the fitting hole of the eccentric body shaft gear and the gear fitting portion of the eccentric body shaft are not limited to this, and may be, for example, a spline or a D-cut shape.

  Further, it is preferable that the fitting between the fitting hole of the eccentric body shaft gear and the gear fitting portion of the eccentric body shaft is “tight fit”. Thereby, for example, the following merits are obtained.

  a) Since the material around the fitting hole of the eccentric shaft gear is soft, the fitting hole shape is harder (carburized / quenched or carburized / high-frequency quenched) by using an interference fit. It is possible to follow the gear fitting portion on the eccentric body shaft side. As a result, even if the finishing process of the fitting hole is omitted, that is, even if there is a slight error in the dimension, the adverse effect due to the error in the dimension of the fitting hole becomes obvious. More can be prevented.

  b) Since the interference fit eliminates “rattle” between the fitting hole and the gear fitting portion, the backlash at this portion can be made substantially zero. This type of eccentric oscillating speed reduction device is often used in applications that do not like backlash, such as robot joint drive, for example, and thus has a great merit that backlash can be reduced.

  c) Since the interference fit eliminates the “rattle” between the fitting hole and the gear fitting portion, it is possible to reduce vibration and noise caused by the rattling. This effect is particularly remarkable when the configuration of the eccentric oscillating type reduction gear is the “distribution type configuration” as described above. This is because, in the case of a distributed type eccentric oscillating speed reduction device, the “shaking” of the eccentric shaft gear is often a major factor in noise generation.

  In addition, since the material is soft, it is possible to easily achieve an interference fit that can achieve the effects a) to c) as compared with the conventional eccentric shaft gear that has been carburized and quenched. That is, the interference fit can be realized by press fitting at a lower pressure without performing shrink fit or press fitting at a high pressure. The effect that the interference fit can be simplified is a very significant merit in the actual manufacturing process.

  The eccentric oscillating type speed reducer has many remarkable effects when applied to the sort type speed reducer as described above. A so-called center crank type speed reducer having one eccentric body shaft at the axial center position of the internal gear is also known. The present invention can be similarly applied to the manufacture of an eccentric body shaft gear for rotating the eccentric body shaft of such a center crank type eccentric oscillating speed reducer, and the same operational effects can be obtained. .

DESCRIPTION OF SYMBOLS 10 ... Reduction gear 12 ... Internal gear 14, 16 ... 1st, 2nd external gear 18 ... Eccentric body shaft 20, 22 ... 1st, 2nd eccentric body 30 ... Eccentric body shaft gear 30T ... Tooth part 30P ... Fit Joint hole 70 ... gear fitting part

Claims (8)

An eccentric body shaft provided with an eccentric body, and an eccentric body shaft gear for rotating the eccentric body shaft, the eccentric body shaft gear being fitted to a gear fitted to the eccentric body shaft at a radial center portion. A manufacturing method of the eccentric body shaft gear of the eccentric oscillating type reduction gear having a fitting hole to be fitted to a joint part,
Forming a tooth portion on the outer periphery of the material of the eccentric body shaft gear; and
Forming the fitting hole in the radial center of the material of the eccentric body shaft gear;
Subjecting the teeth to induction hardening, and making the tooth surface hardness higher than the hardness of the inner peripheral surface of the fitting hole;
The manufacturing method of the eccentric body shaft gear of the eccentric rocking | fluctuation type reduction gear characterized by including these. In claim 1,
The manufacture of an eccentric shaft gear of an eccentric rocking type reduction gear characterized in that the hardness of the tooth surface is higher by 10 points or more in Rockwell hardness HRC than the hardness of the inner peripheral surface of the fitting hole. Method. In claim 1 or 2,
After the induction hardening, the toothed portion is subjected to finishing processing to remove heat treatment strain, but the fitting hole is not subjected to finishing processing to remove heat treatment strain. Of manufacturing eccentric shaft gear of reduction gear of this invention. In claim 1 or 2,
A broaching finish performed on a material having a Rockwell hardness of HRC 50 or less is performed on the fitting hole. A method of manufacturing an eccentric shaft gear of an eccentric rocking type reduction gear. In any one of Claims 1-4,
A material for the eccentric body shaft gear is not subjected to carburizing treatment. An eccentric body shaft gear manufacturing method for an eccentric oscillating type speed reducer. In any one of Claims 1-4,
An eccentric oscillating type speed reducer characterized by subjecting the material of the eccentric body shaft gear to carburizing treatment, gradually cooling in the furnace subjected to the carburizing treatment, and then subjecting the teeth to the induction hardening. Manufacturing method for eccentric shaft gears. An eccentric body shaft provided with an eccentric body, and an eccentric body shaft gear for rotating the eccentric body shaft, the eccentric body shaft gear being fitted to a gear fitted to the eccentric body shaft at a radial center portion. An eccentric oscillating type speed reducer having a fitting hole that fits into a joint part,
The eccentric oscillating speed reducer characterized in that the hardness of the tooth surface of the eccentric body shaft gear is 10 points or more higher in Rockwell hardness HRC than the hardness of the inner peripheral surface of the fitting hole. In claim 7,
The eccentric oscillating speed reduction device, wherein the gear fitting portion of the eccentric body shaft and the fitting hole of the eccentric body shaft gear are fitted by an interference fit.

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