Shaft member for caulking and fastening and bearing device for planetary gear speed reducer

Abstract

To provide a shaft member for caulking and fastening capable of preventing a low-hardness region from spreading to a raceway surface while making a caulked region of the shaft member low hardness.SOLUTION: A shaft member (1) for caulking and fastening is provided with a ring-shaped caulking planned part (14), at both axial end parts, which is caulked and fastened to a member to be fastened, where when an outer diameter of the shaft member (1) is d, a Vickers hardness of a surface of a main region (W2) whose length from an axial end surface of the shaft member exceeds d / 3 is 650 HV or more, and a Vickers hardness of a surface of an endmost region (W3) whose length from the axial end surface of the shaft member is 7d / 30 or less is less than 450 HV.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a planetary gear support structure for a planetary gear device in an automobile transmission or the like, and in particular to a crimping fastening shaft member that rotatably supports a planetary gear and has its shaft end crimped and fixed to a fastened member, and a bearing device for a planetary gear reducer that is equipped with the same. [Background technology]

[0002] 2. Description of the Related Art In a planetary gear mechanism of an automobile transmission, a widely known structure is one in which a shaft member passes through a central hole of a planetary gear (pinion gear), and the shaft member rotatably supports the planetary gear via a rolling bearing.

[0003] 4, a general shaft member 100 is provided in an automobile as part of a bearing device 600 for a planetary gear reducer of a transmission, together with a pinion gear 200 and a rolling bearing 300. The pinion gear 200 is an external gear and has a center hole 210. The center hole 210 extends through the pinion gear 200 from one end surface to the other end surface.

[0004] A cylindrical shaft member 100 is inserted into a central hole 210 of the pinion gear 200, and a rolling bearing 300 is installed in an annular space defined by the inner peripheral surface (central hole 210) of the pinion gear 200 and the outer peripheral surface 110 of the shaft member 100.

[0005] Rolling bearing 300 has a cage 310 and a plurality of rollers 320. The plurality of rollers 320 roll on the raceway surfaces, with the inner circumferential surface (center hole 210) of pinion gear 200 serving as an outer raceway surface and the outer circumferential surface 110 of shaft member 100 serving as an inner raceway surface.

[0006] Both ends 120 of the shaft member 100 protrude from the pinion gear 200. A carrier 400 is attached and fixed to these ends 120. The pinion gear 200 constitutes a planetary gear, meshes with a sun gear and a ring gear (not shown), and rotates while revolving around the sun gear. The carrier 400, which inputs and outputs the revolution motion of the pinion gear 200, is disposed coaxially with the sun gear and the ring gear, and rotates around the central axis of the sun gear. The shaft member 100 rotatably supports the pinion gear 200 via a rolling bearing 300.

[0007] The shaft member 100 is fixed by caulking the end portion 120 to the carrier 400. An example of a shaft member that discloses such a structure is disclosed in Japanese Patent Laid-Open Publication No. 2015-14032 (Patent Document 1).

[0008] 5 is a cross-sectional view showing the structure of a typical shaft member 100 before crimping. The outer peripheral surface (raceway surface) 110 of the shaft member 100 used in a planetary gear mechanism is subjected to a high load when the rollers 320 of the rolling bearing 300 roll, and therefore requires high hardness. In addition, the end portion 120 of the shaft member 100 is crimped and fastened to the carrier 400, and therefore requires a low hardness portion X' that is sufficient to allow the end portion 120 to deform. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2015-14032 A Summary of the Invention [Problem to be solved by the invention]

[0010] Here, the end portion (protruding ring portion) 120 of the shaft member 100 is generally annealed with a high-frequency heating coil to be formed with low hardness. Although Patent Document 1 does not describe the arrangement of the high-frequency heating coil, generally, as shown in FIG. 5, a high-frequency heating coil 500 is arranged on the outer circumferential surface 110 of the end portion 120.

[0011] For the end 120 of the shaft member 100 to deform, the hardness must be low up to the portion that deforms when fastened by crimping, i.e., the inner diameter side of the portion to be crimped (end) 120, which is in the shape of a protruding ring. However, when attempting to make the inner diameter side of the portion to be crimped 120 from the high-frequency heating coil 500 arranged on the outer circumferential surface 110 have a desired hardness, there is a problem in that the low-hardness portion X' spreads to both ends of the raceway surface of the outer circumferential surface 110 of the shaft member 100, lowering the hardness of the ends of the raceway surface. This could cause problems with the shaft member 100 or shorten its lifespan.

[0012] In order to solve the above problems, an object of the present invention is to provide a shaft member having a region to be crimped with a low hardness while preventing the low hardness region from spreading to the raceway surface. [Means for solving the problem]

[0013] The shaft member for crimping fastening according to the present invention is a shaft member for crimping fastening having ring-shaped crimping portions at both axial ends to be crimped to fastened members, and where the outer diameter dimension of the shaft member is d, the Vickers hardness of the main area surface (the raceway surface of a rolling bearing) which is longer than d / 3 from the axial end face of the shaft member is 650 HV or more, and the Vickers hardness of the endmost area surface which is shorter than 7d / 30 from the axial end face of the shaft member is less than 450 HV.

[0014] Preferably, the shaft member has a Vickers hardness of less than 600 HV over a length from the axial end face exceeding 7d / 30 and not exceeding 9d / 30.

[0015] Preferably, the inner circumferential surface of the ring-shaped portion to be crimped is a tapered surface widening toward the end face of the shaft member, and the angle of the tapered surface with respect to the shaft center is 10 to 20°.

[0016] The bearing device for a planetary gear reducer according to the present invention comprises a shaft member for crimping, the shaft member having a ring-shaped intended crimping portion at both axial ends thereof to be crimped to a fastened member, a planetary gear rotatably provided on the outer circumferential surface of the shaft member for crimping via a rolling bearing, and a carrier as a fastened member attached to the intended crimping portion of the shaft member for crimping. The shaft member for crimping has a Vickers hardness of 650 HV or more on a main region surface that is longer than d / 3 from the axial end face of the shaft member, where d is the outer diameter of the shaft member, and a Vickers hardness of less than 450 HV on an endmost region surface that is shorter than 7d / 30 from the axial end face of the shaft member. Effect of the Invention

[0017] According to the shaft member for crimping and fastening of the present invention, the region of the shaft member to be crimped can be made to have a low hardness, while preventing the low hardness region from spreading to the raceway surface.

[0018] Furthermore, according to the bearing device for a planetary gear reducer of the present invention, a shaft member having a long life and made low hardness only in a minimum area is used, so that the life of the device as a whole can be extended. [Brief description of the drawings]

[0019] [Figure 1] 1 is a cross-sectional view showing a schematic view of a swage fastening shaft member according to an embodiment of the present invention. [Diagram 2] 2 is an enlarged cross-sectional view showing a shaft end portion of a shaft member for use in crimping fastening according to one embodiment of the present invention. FIG. [Diagram 3] 4 is a graph showing Vickers hardness at a depth of 0.1 mm from the outer circumferential surface of the shaft member for use in crimping fastening according to the present embodiment and a conventional shaft member. [Figure 4] FIG. 11 is a cross-sectional view showing a state after a conventional shaft member has been crimped and fastened. [Diagram 5] FIG. 11 is a cross-sectional view showing a state before a conventional shaft member is crimped and fastened. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and their description will not be repeated.

[0021] (About the composition) A description will be given of a shaft member 1 for crimping and fastening (hereinafter simply referred to as a "shaft member") according to an embodiment of the present invention with reference to Figures 1 and 2. Figure 1 is a cross-sectional view showing a schematic view of a shaft member according to an embodiment of the present invention. Figure 2 is an enlarged cross-sectional view showing a shaft end portion of the shaft member according to an embodiment of the present invention.

[0022] 1, the shaft member 1 according to this embodiment is a shaft member 1 for crimping, which is provided at both axial ends 11 with ring-shaped portions 14 to be crimped to workpieces. Note that, although the configuration of one end of the shaft member 1 will be mainly described in this specification, the configuration of the other end is similar. Also, all dimensions described in this specification are dimensions of the shaft member 1 before crimping.

[0023] First, the hardness of the shaft member 1 will be described. The outer diameter of the shaft member 1 is d, and the length in the axial direction is W. Of the length W of the shaft member 1, the region where the length from the axial end face 11a is d / 3 or less is W1, and the region where the length from the axial end face 11a is more than d / 3 is W2. In the following description, W1 is also referred to as the end region W1, and W2 is also referred to as the main region W2. In this specification, a Vickers hardness of less than 450HV is referred to as "low hardness", a Vickers hardness of 650HV or more is referred to as "high hardness", and a Vickers hardness of 450HV or more and less than 650HV is referred to as "medium hardness".

[0024] In addition, of the length dimension W1 of the end region, a region that is 7d / 30 or less in length from the axial end face 11a of the shaft member 1 is designated as W3. In the following description, W3 is also referred to as the endmost region W3. The surface of the endmost region W3 has a Vickers hardness of less than 450 HV. In FIG. 1, the region less than 450 HV is indicated by X. In this way, since the endmost region W3 has a low hardness that is sufficiently low for crimping and fastening, it can be crimped and fastened to the fastened members, and defects such as cracking during crimping can be prevented.

[0025] In addition, of the length dimension W1 of the end region, the region where the length from the axial end face 11a of the shaft member 1 exceeds 7d / 30 and is not more than 9d / 30 is designated as W4. In the following description, W4 is also referred to as the first transition region W4. The Vickers hardness of the surface of the first transition region W4 is equal to or greater than the hardness of the endmost region W3 and less than 600HV. In other words, the first transition region W4 is a region where the hardness transitions from low hardness to medium hardness.

[0026] In addition, the region W5 is defined as the region from the axial end surface 11a of the shaft member 1 in the length dimension W1 of the end region that exceeds 9d / 30 and is equal to or less than d / 3. In the following description, W5 is also referred to as the second transition region W5. The surface of the second transition region W5 has a Vickers hardness equal to or greater than that of the first transition region W4 and is formed to approach 650HV. That is, the second transition region W5 is a region where the hardness transitions from medium to high. In other words, the first and second transition regions W4 and W5 can be called "preliminary regions" for ensuring that the surface of the main region W2 has a Vickers hardness of 650HV or more. In this way, the present invention is characterized in that the hardness gradient in the narrow range (W4, W5) is steep, and the low hardness region does not extend to the end of the track surface 13. This allows the track surface 13 of the shaft member to be wide, and the overall length W of the shaft member 1 can be shortened.

[0027] The portion to be swaged 14 has an outer diameter equal to the outer diameter of the shaft member 1, is included in the end region W1 of the shaft member 1, and has an outer peripheral surface 14a, an axial end surface 11a, and an inner peripheral surface 14b. The inner peripheral surface 14b of the portion to be swaged 14 is a tapered surface 14b that spreads toward the axial end surface 11a of the shaft member 1, and the angle of the tapered surface 14b with respect to the axis (rotation axis O) is 10 to 20°. This makes it easier for the portion to be swaged 14 to deform toward the outer diameter direction of the shaft member 1, making it easier to swage and fasten to the carrier. In addition, compared to a portion to be swaged that does not have a tapered surface, the amount of deformation of the portion to be swaged 14 during swage and fastening can be reduced, and the shaft member 1 can be prevented from cracking.

[0028] In the shaft member of this embodiment, the main region W2 including the end of the raceway surface has a sufficiently high hardness, while the endmost region W3 including the region to be swaged has a sufficiently low hardness. In addition, the first and second transition regions W4 and W5 located between the main region W2 and the endmost region W3 have a steep hardness gradient, even though they are narrow. This makes it possible to provide appropriate hardness to both the region where a high hardness is desired and the region where a low hardness is desired.

[0029] (About high frequency heating coils) Next, a high-frequency heating coil 2 for manufacturing a shaft member 1 for crimping and fastening according to the present invention will be described with reference to Fig. 1. The high-frequency heating coil 2 according to this embodiment is a high-frequency heating coil 2 for annealing a ring-shaped portion to be crimped 14 provided at both axial ends 11 of the shaft member 1. The high-frequency heating coil 2 includes an outer peripheral surface heating section 21 for heating an outer peripheral surface 14a of the portion to be crimped 14, an end surface heating section 22 for heating an axial end surface 11a of the portion to be crimped 14, and an inner peripheral surface heating section 23 for heating an inner peripheral surface 14b of the portion to be crimped 14.

[0030] While the conventional high-frequency heating coil 500 shown in Fig. 5 anneals the portion to be crimped 120 of the shaft member 100 only from the outer circumferential surface 110, the high-frequency heating coil 2 of the present invention shown in Fig. 1 anneals the three surfaces 14a, 11, and 14b of the portion to be crimped 14 so as to surround them. This makes it possible to anneal only the desired region more efficiently than in the past. In addition, the low-hardness region can be limited to a narrow region, the endmost region W3, and the low-hardness region can be prevented from spreading to the end of the track surface 13.

[0031] High-frequency heating coil 2 according to the present embodiment heats shaft member 1 not only from outer peripheral surface 14a, but also from axial end surface 11a and inner peripheral surface 14b. This makes it possible to minimize the spread of the thermal effect on outer peripheral surface 10, where the effect of annealing is desired to be suppressed. If the spread of the thermal effect on outer peripheral surface 10 is small, it is possible to ensure a large area of ​​raceway surface 13 with the desired hardness. Therefore, high-frequency heating coil 2 according to the present embodiment can reduce the size of shaft member 1 or increase the range of raceway surface 13 of shaft member 1, and it is expected that the life of the shaft member will be longer than before when used as an inner raceway of a rolling bearing within a limited axial dimension.

[0032] In addition, the Vickers hardness and the hardness gradient in the end region W1 of the shaft member 1 in this embodiment may be adjustable, for example, by the shape and dimensions of the high-frequency heating coil 2, the shape and dimensions of the jig that holds the shaft member 1, the frequency and voltage of the high-frequency annealing device, and the heating and cooling times.

[0033] (Production method) Next, a method for manufacturing the shaft member 1 according to this embodiment will be described.

[0034] First, a carburization prevention step S1 is performed to apply a carburization prevention treatment to the end region W1 of the shaft member 1. In the carburization prevention step S1 of this embodiment, the entire shaft member 1 is copper plated using a known method such as a dipping method or a barrel method, and then a plating removal step S2 is performed to remove the copper plating from the portion corresponding to the raceway surface 13. By the plating removal step S2, only the end region W1 of the shaft member 1 is left in a state in which the carburization prevention treatment has been applied. From the viewpoint of performing the plating removal step S2 efficiently, the plating removal step S2 is performed using a known method such as a coreless grinding. The copper-plated portion is indicated by a dashed line Y in FIG. 2.

[0035] According to the shaft member manufacturing method of this embodiment, copper plating is applied in the carburization step S1. This makes it possible to improve the uniform electrodeposition on the shaft member and suppress erosion of the shaft member. In addition, since the copper plating has a smooth surface, the plating removal step S2 can be easily performed.

[0036] Next, a carburizing and / or carbonitriding process S3 is performed to increase the surface hardness of the raceway surface 13. The carburizing and / or carbonitriding process S3 is a process for incorporating carbon and / or nitrogen into at least the raceway surface 13 of the outer circumferential surface 10 of the shaft member 1 to increase its hardness. After the carbon and / or nitrogen is incorporated, a heat treatment process S4 such as quenching and tempering is performed to harden the raceway surface 13.

[0037] After the heat treatment step S4, an annealing step S5 is performed in which the hardness of the portion 14 to be crimped is reduced using a high-frequency heating coil 2. The annealing step S5 is performed by the high-frequency heating coil 2 disposed adjacent to the portion 14 to be crimped of the shaft member 1. This reduces the hardness of the end region W1 of the shaft member 1 where no carbon and / or nitrogen has been incorporated, and can reduce the hardness to the hardness required for crimping and fastening.

[0038] After the annealing step S5, a grinding step S6 is performed to finish the outer peripheral surface of the shaft member 1 so that the outer peripheral surface has dimensions and precision suitable for the inner raceway surface of a rolling bearing. In the grinding step S6, the copper plating remaining on the outer peripheral surface of the shaft member 1 at the portion to be crimped 14 is also removed.

[0039] (About the Examples) With reference to FIG. 3, the results of evaluation of the hardness of the shaft member of the present invention and the conventional shaft member will be described.

[0040] <About the sample> Comparative Example 1 used a shaft member equivalent to the applicant's conventional shaft member. Examples 1 to 3 used shaft members of the present invention. The dimensions of Comparative Example 1 and Examples 1 to 3 are shaft outer diameter d=15 mm, and depth W6 of tapered surface 14b of intended crimping portion 14=2.5 mm. In addition, end region W1=d / 3=5.0 mm, endmost region W3=7d / 30=3.5 mm, first transition region W4=more than 3.5 mm and 9d / 30=4.5 mm or less, and second transition region W5=more than 4.5 mm and d / 3=5.0 mm or less.

[0041] Moreover, each sample was manufactured under the manufacturing conditions shown in Table 1. Comparative Example 1 and Examples 1 to 3 differ in cooling time. The shape of the high-frequency heating coil also differs in that, while in Comparative Example 1, the portion of the shaft member to be crimped is annealed only from the outer circumferential surface (see high-frequency heating coil 500 in FIG. 5), in Examples 1 to 3, the coil is arranged to surround three sides of the portion to be crimped (see high-frequency heating coil 2 in FIG. 1). Note that the "plate voltage" is the voltage between the cathode and the plate. The "cooling start waiting time" is the time until cooling starts after heating is completed.

[0042] [Table 1]

[0043] <Measurement conditions> For each of Examples 1 to 3 and Comparative Example 1, the Vickers hardness HV was measured at a depth of 0.1 mm from the outer circumferential surface 10. For the shaft member 1, the Vickers hardness HV was measured in a range from the axial end surface 11a to 6.0 mm.

[0044] <About the evaluation results> The measurement results based on the above measurement conditions are shown in Table 2. The values ​​in Table 2 are graphed in Figure 3.

[0045] [Table 2]

[0046] 3, in Comparative Example 1, the low hardness region (region with Vickers hardness less than 450 HV) extends to 4.3 mm, and the medium hardness region (region with Vickers hardness of 450 HV or more and less than 650 HV) extends to 5.3 mm. That is, in the shaft member of Comparative Example 1, the medium hardness region extends to the main region W2 (region at a distance of 5.0 mm or more from the shaft end face) where high hardness is required, and the Vickers hardness in all regions of the main region W2 could not reach high hardness (650 HV or more).

[0047] In Example 1, the Vickers hardness in the end region W3 was kept low at 450HV or less, while the hardness increased by 210HV or more between the first and second transition regions W4 and W5, and the Vickers hardness in the main region W2 was made high at 650HV or more. In Example 2, the Vickers hardness in the end region W3 was kept low at 450HV or less, while the hardness increased by 260HV or more between the first and second transition regions W4 and W5, and the Vickers hardness in the main region W2 was made high at 650HV or more. In Example 3, the Vickers hardness in the end region W3 was kept low at 450HV or less, while the hardness increased by about 250HV between the first and second transition regions W4 and W5, and the Vickers hardness in the main region W2 was made high at 650HV or more.

[0048] From the results of Examples 1 to 3, it was found that the shaft member of this embodiment has an optimum hardness for both the endmost region W3 to be fastened by crimping, and the main region W2 capable of withstanding the load applied when the rolling bearing rolls, by transitioning the Vickers hardness from low to high between the narrow first and second transition regions W4, W5 of 1.5 mm.

[0049] (Material composition) Next, the material composition of the shaft member of this embodiment will be described.

[0050] The shaft member preferably has a carbon content of 0.15 to 0.30 mass %. This makes it possible to suppress an increase in hardness of the shaft end during the heat treatment process. Furthermore, by setting the carbon content to the above value, the amount of retained austenite in the core of the shaft member can be set to 3 volume % or less. A small amount of retained austenite can prevent creep deformation of the shaft member, and therefore can prevent plastic deformation of the shaft member when used in a high-temperature environment.

[0051] The shaft member preferably contains 0.1 to 1.2 mass% silicon, 0.3 to 1.2 mass% manganese, 0 to 1.6 mass% chromium, and 0 to 0.3 mass% molybdenum. By containing silicon in the above proportions, temper softening resistance is improved, softening during tempering can be suppressed, and durability of the shaft member in a high-temperature environment can be improved. In addition, precipitation of nitrides can be promoted. By containing manganese in the above proportions, hardening during quenching can be promoted and austenite can be stabilized. By containing chromium and molybdenum in the above proportions, hardenability and temper softening resistance can be improved, and durability of the shaft member in a high-temperature environment can be improved.

[0052] In addition, the surface layer of the shaft member preferably has a retained austenite content of 25% by volume or more. With a retained austenite content of 25% by volume or more, even if foreign matter is caught in the lubricating oil and foreign matter is contained therein, the presence of relatively soft retained austenite reduces the swelling around the indentation, so that the shaft member can be expected to have a longer life. However, an excessive amount of retained austenite can lead to a decrease in surface hardness and dimensional changes over time, so the upper limit is preferably 40% by volume.

[0053] The surface layer of the shaft member preferably has a nitrogen concentration of 0.1% by mass or more and 1.2% by mass or less. By making it 0.1% by mass or more, the amount of retained austenite in the surface layer increases, improving the rolling fatigue life in a harsh environment including lubricating oil containing foreign matter, and improving the durability of the shaft member in a high-temperature environment by improving the tempering softening resistance. By making it 1.2% by mass or less, it is possible to prevent the hardness of the surface layer from decreasing due to an excessive amount of retained austenite, and to prevent dimensional changes over time.

[0054] It is more preferable that the nitrogen concentration of the surface layer of the shaft member is 0.2% by mass or more and 0.7% by mass or less. This provides the surface layer with sufficient hardness, improving the wear resistance and rolling fatigue life. In addition, it is possible to prevent a decrease in hardness and dimensional changes over time that are caused by an excess amount of retained austenite due to an excessive nitrogen concentration.

[0055] The surface layer of the shaft member preferably has a carbon concentration of 0.6 to 1.2 mass%. By setting the carbon concentration at 0.6 mass% or more, it is possible to provide a shaft member that functions as an inner raceway of a rolling bearing with an appropriate surface hardness. However, an excessive carbon concentration can cause abnormal structures such as reticulated cementite to form in the surface layer, so the upper limit is preferably set at 1.2 mass%. From the viewpoint of reliably preventing the formation of abnormal structures, it is even more preferable to set the upper limit of the carbon concentration at 0.9 mass%.

[0056] The surface layer of the shaft member preferably has an average grain size of prior austenite of 22.1 μm or less. This improves resistance to indentation and crack growth caused by lubricating oil containing foreign matter, and improves the rolling life. The smaller the average grain size of the prior austenite grains, the more preferable. This makes it difficult for cracks to occur in the shaft member, and even if cracks do occur, their growth can be delayed, thereby improving the rolling life.

[0057] The core of the shaft member preferably has a retained austenite amount of 3 volume % or less, which can prevent the retained austenite from creeping and causing plastic deformation of the shaft member.

[0058] The embodiments disclosed herein are illustrative in all respects and should not be considered as limiting. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0059] 1 Shaft member for crimping and fastening, 2 High frequency heating coil, 10 Outer peripheral surface, 11 Both axial ends, 11a Axial end face, 12 Surface, 13 Raceway surface, 14 Part to be crimped, 14b Tapered surface, 21 Outer peripheral surface heating portion, 22 End face heating portion, 23 Inner peripheral surface heating portion, 120 Both ends (end portions).

Claims

1. A shaft member for crimping, which is provided at both axial ends with ring-shaped portions to be crimped to be fastened to workpieces, If the outer diameter of the shaft member is d, The Vickers hardness of the surface of the main region of the shaft member whose length from the axial end face exceeds d / 3 is 650 HV or more, A shaft member for use in crimping and fastening, wherein the Vickers hardness of the surface of an end region of the shaft member, the length of which from an axial end face is 7d / 30 or less, is less than 450 HV.

2. 2. The shaft member for use in crimping and fastening according to claim 1, wherein the shaft member has a Vickers hardness of less than 600 HV at a length from an axial end face exceeding 7d / 30 and not exceeding 9d / 30.

3. an inner circumferential surface of the ring-shaped portion to be crimped is a tapered surface that widens toward an end face of the shaft member, 3. The shaft member for use in crimping and fastening according to claim 1, wherein an angle of said tapered surface with respect to a shaft center is 10 to 20 degrees.

4. a shaft member for crimping, the shaft member having ring-shaped portions to be crimped at both axial ends thereof, the portions being to be crimped to workpieces; a planetary gear rotatably provided on an outer circumferential surface of the swage fastening shaft member via a rolling bearing; a carrier as the fastened member attached to the portion to be fastened of the fastening shaft member, The swage fastening shaft member is If the outer diameter of the shaft member is d, The Vickers hardness of the surface of the main region of the shaft member whose length from the axial end face exceeds d / 3 is 650 HV or more, A bearing device for a planetary gear reducer, wherein the Vickers hardness of the surface of an end region of the shaft member, the length of which from the axial end face is 7d / 30 or less, is less than 450 HV.

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