JP2022021739A - Rotary body support shaft and planetary gear train - Google Patents

Abstract

To provide a rotary body support shaft that can achieve reduction in production cost, and a planetary gear train.SOLUTION: In a planetary gear train 1, a rotary body support shaft 61 for supporting a planetary gear 4 through a roller bearing 5, has: a shaft body 7 formed with a shaft hole 70 opened in a shaft end face 7a; and a spherical body 8 press-fitted into the shaft hole 70. The shaft body 7 is formed with an introduction hole 71 for introducing lubricant into the shaft hole 70, and a lead-out hole 72 for leading out the lubricant introduced into the shaft hole 70 toward the roller bearing 5, with the spherical body 8 fitted and fixed to the side of the shaft hole 70 closer to the shaft end face 7a than the introduction hole 71 and the lead-out hole 72.SELECTED DRAWING: Figure 2

Description

The present invention relates to a rotating body support shaft and a planetary gear device provided with the rotating body support shaft.

Conventionally, a planetary gear device including a plurality of planetary gears supported on a support shaft via bearings has been used, for example, as a power transmission device for shifting and transmitting the driving force of an automobile. The support shaft of the planetary gear device described in Patent Document 1 has a hollow hole formed in the center in which one end in the axial direction is opened and extends in the axial direction, and a lubricating oil for supplying lubricating oil to the hollow hole is formed. A supply inlet hole and a lubricating oil supply outlet hole for supplying the lubricating oil supplied to the hollow hole to the bearing are formed so as to penetrate between the inner and outer peripheral surfaces of the support shaft. The opening at one end of the hollow hole is closed by a plug formed by pressing a flat plate-shaped plug material arranged on the end opening side of the support shaft into the hollow hole of the support shaft with a punch and drawing it into a bottomed cylindrical shape. ing.

Japanese Unexamined Patent Publication No. 2005-321026

In the case described in Patent Document 1, when the plug material is press-fitted into the hollow hole of the support shaft with a punch, the plug material may be scraped at the open end of the hollow hole to generate burrs, so that burrs are generated. A process of inspecting the presence or absence of burrs and removing burrs is required, which causes an increase in manufacturing cost. In addition, in order to draw and shape the plug material into a bottomed cylinder so that the plug does not fall out of the hollow hole, the outer diameter of the punch and the inner diameter of the hollow hole must be strictly controlled, which is also a manufacturing cost. Is a factor that increases.

Therefore, an object of the present invention is to provide a rotating body support shaft and a planetary gear device capable of reducing manufacturing costs.

The present invention is a rotating body support shaft that supports a rotating body via a bearing having a plurality of rolling elements in order to achieve the above object, and is a shaft-shaped body having a shaft hole opened in a shaft end face. A spherical body press-fitted into the shaft hole, the shaft-shaped body has an introduction hole for introducing lubricating oil into the shaft hole, and a derivation for leading out the lubricating oil introduced into the shaft hole toward the bearing. Provided is a rotating body support shaft in which a hole is formed and the sphere is fitted and fixed to the shaft end face side of the introduction hole and the lead-out hole in the shaft hole.

Further, in order to achieve the above object, the present invention is arranged between a sun gear having an external tooth, an internal gear having an internal tooth, and the sun gear and the internal gear, and the external tooth and the internal gear. A planetary gear that meshes with the internal teeth and is supported by the rotating body support shaft, a bearing having a plurality of rolling elements interposed between the planetary gear and the rotating body support shaft, and a rotating body support shaft. Provided is a planetary gear device with a carrier with one end fixed.

According to the rotating body support shaft and the planetary gear device according to the present invention, it is possible to reduce the manufacturing cost.

It is an exploded perspective view which shows the planetary gear apparatus using the rotating body support shaft which concerns on 1st Embodiment of this invention. A planetary gear and a support shaft are shown, (a) is an axial cross-sectional view along the axial direction, and (b) is an axial cross-sectional view taken along the line AA of (a). It is explanatory drawing which shows the shaft-shaped body and a sphere, and the press-fitting jig for press-fitting a sphere into a shaft hole of a shaft-shaped body, (a) shows the state before the sphere is press-fitted into a shaft hole. (B) shows a state in which a sphere is press-fitted into the shaft hole. (A) is a cross-sectional view showing a shaft-shaped body according to a second embodiment of the present invention together with a sphere. (B) is an enlarged view of part B of (a). (C) is a cross-sectional view showing a support shaft. (A) is a cross-sectional view showing a state in which a support shaft according to a third embodiment of the present invention is fixed to a carrier and supports a planetary gear via a roller bearing. (B) is a cross-sectional view showing a shaft-shaped body of a support shaft as a single unit. (A) is a cross-sectional view showing a state in which a support shaft according to a fourth embodiment of the present invention is fixed to a carrier and supports a planetary gear via a roller bearing. (B) is a cross-sectional view showing a shaft-shaped body of a support shaft as a single unit. (A) is a cross-sectional view showing a state in which a support shaft according to a fifth embodiment of the present invention is fixed to a carrier and supports a planetary gear via a roller bearing. (B) is a cross-sectional view showing a shaft-shaped body and a sphere of a support shaft. (A) is a cross-sectional view showing a state in which a support shaft according to a sixth embodiment of the present invention is fixed to a carrier and supports a planetary gear via a roller bearing. (B) is a cross-sectional view showing a shaft-shaped body and a sphere of a support shaft. (A) and (b) are sectional views which show the modification of the shaft-shaped body which concerns on 6th Embodiment.

[First Embodiment]
Embodiments of the present invention will be described with reference to FIGS. 1 to 3. It should be noted that the embodiments described below are shown as suitable specific examples for carrying out the present invention, and there are some parts that specifically exemplify various technically preferable technical matters. , The technical scope of the present invention is not limited to this specific aspect.

(Overall configuration of planetary gears)
FIG. 1 is an exploded perspective view showing a planetary gear device using a rotating body support shaft (hereinafter referred to as “support shaft”) according to the present embodiment. 2A and 2B show a planetary gear and a support shaft, FIG. 2A is an axial cross-sectional view along the axial direction, and FIG. 2B is an axial cross-sectional view taken along the line AA of FIG. 2A.

The planetary gear device 1 is arranged between the external gear 2 having external teeth 21 on the outer peripheral surface, the internal gear 3 having internal teeth 31 on the inner peripheral surface, and the external gear 2 and the internal gear 3. A planetary gear 4 as a plurality of (three in this embodiment) rotating bodies having external teeth 41 that mesh with the external teeth 21 and internal teeth 31, and a plurality of rollers arranged inside the plurality of planetary gears 4, respectively. The bearing 5 includes a plurality of (three) support shafts 61 that support the planetary gears 4 via the roller bearings 5, and a carrier 6 having a frame body 62 to which these support shafts 61 are fixed. The external gear 2, the internal gear 3, and the carrier 6 are arranged coaxially so as to be relatively rotatable.

This planetary gear device 1 is used, for example, in a transmission that shifts the rotation of the rotary shaft (crankshaft) of an engine that is a drive source of an automobile, and is among the three elements of an external gear 2, an internal gear 3, and a carrier 6. , One element is fixed and torque is input to the other element, so that the input torque is transmitted to the remaining one element by decelerating or increasing the speed. The sliding of each part of the planetary gear device 1 is lubricated by a lubricating oil (for example, transmission oil).

The external gear 2 has a shaft 20 fixed to the center thereof so as not to rotate relative to each other, and is arranged concentrically with the internal gear 3 and the carrier 6. The planetary gear 4 has a roller bearing 5 housed in a shaft hole 40 penetrating the central portion thereof. The roller bearing 5 has a plurality of needle-shaped rollers 51 as rolling elements and a cage 52 for holding the plurality of needle-shaped rollers 51. The needle-shaped roller 51 is arranged so as to be interposed between the inner peripheral surface 40a of the shaft hole 40 of the planetary gear 4 and the support shaft 61.

For example, when the internal gear 3 is fixed and the shaft 20 rotates, the rotation of the external gear 2 that rotates with the shaft 20 is decelerated and output to the output shaft shown in the figure that rotates integrally with the carrier 6. At this time, the plurality of planetary gears 4 revolve around the rotation axis O of the shaft 20 and rotate around the center axis C of the support shaft 61.

The frame body 62 has outer diameters of the first and second annular plates 621 and 622 and the first and second annular plates 621 and 622, respectively, which sandwich the plurality of planetary gears 4 in the axial direction along the central axis C. It has a bridge wall 623 that bridges the end portions on the side, and a fitting cylinder 624 fixed to the end portion on the inner diameter side of the first annular plate 621. A spline fitting portion 620 into which the output shaft is fitted is formed on the inner circumference of the fitting cylinder 624.

Each support shaft 61 includes a shaft-shaped body 7 having a shaft hole 70 formed in the center thereof and a sphere 8 press-fitted into the shaft hole 70, and is inserted into the shaft hole 40 of the planetary gear 4. There is. The shaft hole 70 is a round hole having a constant inner diameter. The shaft-shaped body 7 is made of, for example, carbon steel. The sphere 8 is a steel sphere made of a metal harder than the shaft-shaped body 7, and is made of, for example, hardened and tempered bearing steel. As the sphere 8, for example, a ball of a ball bearing can be diverted. The hardness of the sphere 8 is, for example, 60.5 to 68.0 HRC.

The shaft-shaped body 7 has one end in the axial direction fitted in the fitting hole 621a formed in the first annular plate 621, and the other in the axial direction in the fitting hole 622a formed in the second annular plate 622. The ends are fitted. The shaft hole 70 opens in the shaft end surface 7a at one end of the shaft-shaped body 7 and extends in the axial direction of the shaft-shaped body 7. Further, the shaft hole 70 is machined from the shaft end surface 7a toward the other end of the shaft-shaped body 7 by using, for example, an end mill, but reaches the shaft end surface 7b at the other end of the shaft-shaped body 7. It is not formed and is formed as a blind hole. That is, the shaft hole 70 is opened only at one end of the shaft-shaped body 7, and the other end of the shaft-shaped body 7 is closed by the remaining meat.

The shaft-shaped body 7 is formed with an introduction hole 71 for introducing lubricating oil into the shaft hole 70, and a lead-out hole 72 for leading out the lubricating oil introduced into the shaft hole 70 toward the roller bearing 5. In the present embodiment, the shaft-shaped body 7 is provided with one introduction hole 71 and one lead-out hole 72, but the number of the introduction hole 71 or the lead-out hole 72 may be a plurality. The introduction hole 71 and the lead-out hole 72 are formed so as to penetrate between the inner peripheral surface 7c and the outer peripheral surface 7d of the shaft-shaped body 7. The outer peripheral surface 7d of the shaft-shaped body 7 is formed as a raceway surface 7e on which a plurality of needle-shaped rollers 51 roll, except for both ends in the axial direction of the shaft-shaped body 7. The outer peripheral surface 7d of the shaft-shaped body 7 is ground by, for example, a cylindrical grinding machine before the sphere 8 is press-fitted into the shaft hole 70.

The introduction hole 71 and the lead-out hole 72 are opened in the shaft hole 70 at different positions in the axial direction of the shaft-shaped body 7. Specifically, an introduction hole 71 is opened near the shaft end surface 7b at the other end of the shaft-shaped body 7 in which the shaft hole 70 is closed, and a lead-out hole 72 is opened at the axial center portion of the shaft-shaped body 7. There is. Further, the introduction hole 71 is formed inside the shaft hole 70 in the radial direction of the carrier 6, and the lead-out hole 72 is formed outside the shaft hole 70 in the radial direction of the carrier 6.

The second annular plate 622 is formed with an oil supply path 63 communicating with the introduction hole 71. One end of the oil supply passage 63 opens to the inner peripheral surface 622b of the second annular plate 622, and the other end thereof opens to the fitting hole 622a. The lubricating oil that has entered from one end of the oil supply path 63 flows by the centrifugal force generated by the rotation of the carrier 6 and is introduced into the shaft hole 70 from the introduction hole 71. The lubricating oil introduced into the shaft hole 70 is supplied to the roller bearing 5 from the outlet hole 72, and lubricates the sliding of the plurality of needle-shaped rollers 51 and the cage 52.

The shaft-shaped body 7 is formed with a positioning fitting hole 73 on the outer peripheral surface of one end on the first annular plate 621 side, and the positioning pin 64 is fitted in the positioning fitting hole 73. The positioning pin 64 is press-fitted into the pin hole 640 formed in the first annular plate 621, and its tip is fitted into the positioning fitting hole 73. The shaft-shaped body 7 is prevented from rotating with respect to the frame body 62 by the positioning pin 64, and is positioned in the axial direction.

FIG. 3 is an explanatory diagram showing the shaft-shaped body 7 and the sphere 8 and the press-fitting jig 9 for press-fitting the sphere 8 into the shaft hole 70 of the shaft-shaped body 7, and FIG. 3A is an explanatory diagram showing the shaft-shaped body 7 into the shaft hole 70. The state before the sphere 8 is press-fitted is shown, and (b) shows the state where the sphere 8 is press-fitted into the shaft hole 70.

In the shaft-shaped body 7, an annular recess 74 is formed on the inner peripheral surface 7c of the shaft hole 70 on the shaft end surface 7a side of the introduction hole 71 and the lead-out hole 72. A sphere 8 is arranged in the recess 74. The inner diameter D1 of the shaft hole 70 on both sides of the recess 74 in the axial direction is formed to be slightly smaller than the diameter D2 of the sphere 8. The diameter D2 of the sphere 8 is, for example, 10 mm to 15 mm. The difference between the inner diameter D1 of the shaft hole 70 and the diameter D2 of the sphere 8 is, for example, 20 ± 10 μm. The sphere 8 is axially prevented from coming off from the recess 74 because the inner diameter D1 of the shaft hole 70 on both sides of the recess 74 in the axial direction is smaller than the diameter D2. In addition, in FIGS. 2 and 3, the difference between the inner diameter D1 of the shaft hole 70 and the diameter D2 of the sphere 8 is exaggerated for the sake of clarification of the explanation.

The recess 74 is formed so as to be recessed outward in the radial direction from the inner peripheral surface 7c of the shaft hole 70. In the present embodiment, the recess 74 is formed in an arc shape in the axial cross section of the axial body 7. Further, in the present embodiment, the inner diameter of the recess 74 has a dimension without a tightening margin with respect to the diameter D2 of the sphere 8, and the maximum diameter D3 of the recess 74 is formed to be slightly larger than the diameter D2 of the sphere 8. .. That is, when the sphere 8 passes through the shaft hole 70 having the inner diameter D1 from the shaft end surface 7a side to the recess 74, the sphere 8 is in a state of not receiving the compressive stress from the shaft-shaped body 7. Here, the "inner diameter of the recess 74" means the inner diameter of the shaft hole 70 of the portion where the recess 74 is formed in the direction perpendicular to the central axis C of the support shaft 61.

Since the sphere 8 is arranged in the recess 74, the lubricating oil introduced into the shaft hole 70 from the introduction hole 71 is suppressed from leaking from the opening of the shaft hole 70 in the shaft end surface 7a, and is prevented from leaking from the outlet hole 72. More lubricating oil can be supplied to the roller bearing 5. The sphere 8 is press-fitted into the shaft hole 70 from the opening on the shaft end surface 7a side at one end of the shaft-shaped body 7 by the press-fitting jig 9 and arranged in the recess 74. At this time, the portion on the shaft end surface 7a side of the recess 74 is elastically deformed so as to be expanded in diameter by the sphere 8.

The press-fitting jig 9 has a main body portion 91 having a facing surface 91a facing the shaft end surface 7a when the sphere 8 is press-fitted into the shaft hole 70, and a boss portion 92 having a flat surface 92a abutting on the sphere 8. There is. The boss portion 92 is a short columnar shape having an outer diameter smaller than the inner diameter D1 of the shaft hole 70. The axial length L of the boss portion 92 from the facing surface 91a is a dimension corresponding to the press-fitting length of the sphere 8. The press-fitting jig 9 moves relative to the shaft-shaped body 7 in the axial direction until the facing surface 91a abuts on the shaft end surface 7a, and press-fits the sphere 8. When the facing surface 91a comes into contact with the shaft end surface 7a, the sphere 8 is arranged in the recess 74.

(Effect of the first embodiment)
According to the first embodiment of the present invention described above, the shaft-shaped body 7 is deformed when the sphere 8 is press-fitted into the shaft hole 70, but the amount of deformation is the inner diameter D1 of the shaft hole 70 and the sphere 8. Since it is a small amount corresponding to the difference from the diameter D2 of, the generation of burrs is suppressed. Further, when the sphere 8 is press-fitted into the shaft hole 70, the angle formed by the surface of the sphere 8 and the inner peripheral surface 7c of the shaft hole 70 is shallow, so that the inner peripheral surface 7c of the shaft hole 70 is difficult to be scraped. However, the generation of burrs is suppressed. As a result, the amount of work for removing burrs can be reduced as compared with, for example, those described in Patent Document 1, and the work of press-fitting the sphere 8 into the shaft hole 70 is easy. It is possible to reduce the cost.

Further, in the present embodiment, since the inner diameter of the recess 74 has a dimension that does not have a tightening margin with respect to the diameter D2 of the sphere 8, the shaft-shaped body 7 is elastically deformed when the sphere 8 is arranged in the recess 74. Instead, the change in the track diameter of the track surface 7e before and after arranging the sphere 8 in the recess 74 is suppressed, and the plurality of needle-shaped rollers 51 can be smoothly rolled.

Further, in the present embodiment, since the recess 74 is arcuate in the axial cross section of the shaft-shaped body 7, for example, the shaft-shaped body 7 and the cutting tool are used while changing the feed amount of the cutting tool (bite) in the shaft hole 70. The recess 74 can be easily and accurately formed by performing the turning process by moving the metal relative to the axial direction. Further, since the concave portion 74 has an arcuate shape, a region where the distance between the inner surface 74a of the concave portion 74 and the surface of the sphere 8 is narrow can be formed long in the axial direction, and the inner surface 74a of the concave portion 74 and the surface of the sphere 8 can be formed. It is possible to prevent the lubricating oil from leaking from the gap between the two.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 4A is a cross-sectional view showing the axial body 7A according to the present embodiment together with the sphere 8. FIG. 4 (b) is an enlarged view of a portion B of FIG. 4 (a). FIG. 4C is a cross-sectional view showing a support shaft 61A according to the present embodiment.

The support shaft 61A is used to support the planetary gear 4 via the roller bearing 5 in the same manner as the support shaft 61 according to the first embodiment. In the present embodiment and the third to sixth embodiments described later, the same reference numerals as those attached to FIG. 3 are used for the components substantially in common with those described in the first embodiment. Duplicate explanations will be omitted.

In the first embodiment, the case where the maximum diameter D3 of the recess 74 is formed larger than the diameter D2 of the sphere 8 has been described, but in the present embodiment, the maximum diameter D3 of the recess 74 is the diameter of the sphere 8. It has the same diameter as D2. The inner diameter D1 of the shaft hole 70 on both sides of the recess 74 in the axial direction is formed to be smaller than the diameter D2 of the sphere 8 and the maximum diameter D3 of the recess 74.

The shape of the recess 74 in the axial cross section of the shaft-shaped body 7A is an arc shape as in the first embodiment, but in the present embodiment, in the state before the sphere 8 is press-fitted into the shaft hole 70. The radius of curvature of the inner surface 74a of the recess 74 in the axial cross section of the axial body 7A is formed to be smaller than the radius (D2 / 2) of the sphere 8. As a result, in the state where the sphere 8 is arranged in the recess 74, the corner portions 741 at both ends in the axial direction of the recess 74 are in contact with the sphere 8 along the circumferential direction of the recess 74. In other words, the corner portion 741 is pressed against the surface of the sphere 8, thereby restricting the axial movement of the sphere 8. The corner portion 741 is formed in an annular shape at the boundary between the inner surface 74a of the recess 74 and the inner peripheral surface 7c of the shaft hole 70 having the inner diameter of D1. Further, when the corner portion 741 abuts on the sphere 8, the leakage of the lubricating oil from the opening of the shaft hole 70 is suppressed.

As shown in FIGS. 4A and 4B, the shaft-shaped body 7A is in a state before the sphere 8 is press-fitted into the shaft hole 70, and has a portion corresponding to the radial outer side of the recess 74 and a shaft rather than the recess 74. The outer diameter of the portion of the hole 70 on the opening side is smaller than the outer diameter of the raceway surface 7e on the introduction hole 71 and the lead-out hole 72 side of the recess 74. In FIG. 4B, a two-dot chain line shows a virtual line VL in which the raceway surface 7e on the introduction hole 71 and the lead-out hole 72 side is extended from the recess 74. The portion formed with a small outer diameter includes a part of the raceway surface 7e on which the plurality of needle-shaped rollers 51 roll after the sphere 8 is arranged in the recess 74.

The outer diameter of the shaft-shaped body 7A of the portion corresponding to the radial outer side of the recess 74 and the portion on the opening side of the shaft hole 70 from the recess 74 is due to the plastic strain generated by the sphere 8 being press-fitted into the shaft hole 70. The diameter is expanded so that the difference from the outer diameter of the raceway surface 7e on the side of the introduction hole 71 and the outlet hole 72 is smaller than that of the recess 74. That is, the shaft-shaped body 7A expands at least a part of the axial range through which the sphere 8 passes when the sphere 8 is press-fitted into the recess 74, so that the outer diameter of at least a part thereof and the press-fitting time are performed. The outer diameter of the portion through which the sphere 8 does not pass is equalized. This makes it possible to make the track diameter of the raceway surface 7e substantially uniform over the entire axial direction even when plastic strain is generated by press-fitting the sphere 8.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 5A is a cross-sectional view showing a state in which the support shaft 61B according to the present embodiment is fixed to the carrier 6 and supports the planetary gear 4 via the roller bearing 5. FIG. 5B is a cross-sectional view showing the axial body 7B of the support shaft 61B as a single unit.

In the first and second embodiments, the case where the recess 74 in which the sphere 8 is arranged has an arcuate cross section has been described, but in the present embodiment, the shape of the recess 74 in the axial cross section of the axial body 7B Is rectangular, and the bottom surface 74b of the recess 74 is formed parallel to the raceway surface 7e. The pair of side surfaces 74c of the recesses 74 facing each other across the bottom surface 74b are annular planes perpendicular to the bottom surface 74b. The inner diameter D4 of the bottom surface 74b in the recess 74 is slightly larger than the diameter D2 of the sphere 8, but the inner diameter D4 of the bottom surface 74b may be the same as the diameter D2 of the sphere 8. The corners 741 at both ends of the recess 74 in the axial direction are in contact with the sphere 8 along the circumferential direction of the recess 74. The corner portion 741 is formed in an annular shape at the boundary between each of the pair of side surfaces 74c and the inner peripheral surface 7c of the shaft hole 70 having an inner diameter of D1 smaller than the diameter D2 of the sphere 8.

Similar to the first and second embodiments, the third embodiment can also suppress the generation of burrs, reduce the manufacturing cost, and can be used from the opening of the shaft hole 70. Leakage of lubricating oil can be suppressed.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 6A is a cross-sectional view showing a state in which the support shaft 61C according to the present embodiment is fixed to the carrier 6 and supports the planetary gear 4 via the roller bearing 5. FIG. 6B is a cross-sectional view showing the axial body 7C of the support shaft 61C as a single unit.

In the axial body 7C, the shape of the concave portion 74 in the axial cross section is triangular, and the inner surface of the concave portion 74 is a first inclined surface 74d and a first inclined surface 74d inclined in opposite directions to the axial direction of the axial body 7C. It is formed by the inclined surface 74e of 2. The sphere 8 is loosely fitted between the first inclined surface 74d and the second inclined surface 74e, but the first inclined surface 74d and the second inclined surface are along the circumferential direction of the axial body 7C. It may be in contact with 74e in an annular shape. The sphere 8 is press-fitted into a shaft hole 70 having an inner diameter of D1 smaller than its diameter D2 and arranged in the recess 74.

Similar to the first and second embodiments, the fourth embodiment also suppresses the generation of burrs and makes it possible to reduce the manufacturing cost.

[Fifth Embodiment]
Next, a fifth embodiment of the present invention will be described with reference to FIG. 7. FIG. 7A is a cross-sectional view showing a state in which the support shaft 61D according to the present embodiment is fixed to the carrier 6 and supports the planetary gear 4 via the roller bearing 5. FIG. 7B is a cross-sectional view showing a shaft-shaped body 7D and a sphere 8 of the support shaft 61D.

In the present embodiment, as in the first and second embodiments, the recess 74 in which the sphere 8 is arranged has an arcuate cross section, but from the maximum diameter D3 of the recess 74 before the sphere 8 is press-fitted. The diameter D2 of the sphere 8 is large, and the outer peripheral surface 7d at one end of the shaft-shaped body 7D whose diameter is expanded by press-fitting the sphere 8 into the shaft hole 70 is the inner circumference of the fitting hole 621a of the first annular plate 621. It is tightly fitted to the surface 621b. More specifically, in the state before the sphere 8 is press-fitted, the outer diameter of the shaft-shaped body 7D is smaller than the inner diameter of the fitting hole 621a, and one end of the shaft-shaped body 7D is easily inserted into the fitting hole 621a. By press-fitting the sphere 8 into the shaft hole 70 with one end of the shaft-shaped body 7D arranged in the fitting hole 621a, the outer peripheral surface 7d at one end of the shaft-shaped body 7D is expanded. It has a diameter and is fastened to the inner peripheral surface 621b of the fitting hole 621a. This makes it possible to more firmly fix the support shaft 61D to the carrier 6 in addition to the effects of the first and second embodiments.

Note that FIG. 7A shows a case where a part of the recess 74 is formed inside the fitting hole 621a, but the recess 74 is centered in the axial direction of the axial body 7D with respect to the fitting hole 621a. It may be formed closer to each other. However, if a part of the recess 74 is formed inside the fitting hole 621a, the force of the sphere 8 to expand the diameter of the shaft-shaped body 7D is directly applied to the outer peripheral surface 7d of the shaft-shaped body 7D and the inside of the fitting hole 621a. Since it acts on the peripheral surface 621b, the support shaft 61D can be more firmly fixed to the carrier 6.

[Sixth Embodiment]
Next, a sixth embodiment of the present invention will be described with reference to FIG. FIG. 8A is a cross-sectional view showing a state in which the support shaft 61E according to the present embodiment is fixed to the carrier 6 and supports the planetary gear 4 via the roller bearing 5. FIG. 8B is a cross-sectional view showing a shaft-shaped body 7E and a sphere 8 of the support shaft 61E.

In the first to fifth embodiments, the case where the sphere 8 is held in the recess 74 formed in an annular shape on the inner peripheral surface 7c of the shaft hole 70 has been described, but in the present embodiment, the shaft-shaped body 7E has been described. The holding structure of the sphere 8 in the above is different.

The shaft hole 70 of the shaft-shaped body 7E has a large inner diameter portion 75 that opens in the shaft end surface 7a, and a small inner diameter portion 76 whose inner diameter is smaller than that of the large inner diameter portion 75. The large inner diameter portion 75 and the small inner diameter portion 76 are aligned in the axial direction with the central axis C as the center and communicate with each other. The introduction hole 71 and the lead-out hole 72 are open to the small inner diameter portion 76. A step portion 77 is formed between the large inner diameter portion 75 and the small inner diameter portion 76. The stepped portion 77 has a stepped surface 77a between the inner peripheral surface 75a of the large inner diameter portion 75 and the inner peripheral surface 76a of the small inner diameter portion 76. The step surface 77a is an annular plane that is perpendicular to the axial direction and directs an opening on the shaft end surface 7a side at one end of the shaft-shaped body 7E. The width of the stepped surface 77a in the radial direction of the shaft-shaped body 7E is one half of the difference between the inner diameter D5 of the large inner diameter portion 75 and the inner diameter D6 of the small inner diameter portion 76.

The sphere 8 is press-fitted into the large inner diameter portion 75 from the opening on the shaft end surface 7a side and is in contact with the step portion 77. In other words, the sphere 8 is press-fitted from the opening at one end of the shaft-shaped body 7E toward the small inner diameter portion 76 until it comes into contact with the stepped portion 77. The sphere 8 is in annular contact with the corner portion between the stepped surface 77a and the inner peripheral surface 76a of the small inner diameter portion 76.

The inner diameter D5 of the large inner diameter portion 75 is smaller than the diameter D2 of the sphere 8 in the natural state before being press-fitted. The sphere 8 has not been subjected to heat treatment such as quenching or tempering, and is elastically deformed when it is press-fitted into the large inner diameter portion 75. As a result, the change in the track diameter of the track surface 7e is suppressed, and the plurality of needle-shaped rollers 51 can be smoothly rolled.

If the outer diameter of the shaft-shaped body 7E at the portion where the sphere 8 is press-fitted becomes large by press-fitting the sphere 8 into the large inner diameter portion 75, the outer diameter of the portion should be formed small in advance. Is desirable. That is, in the shaft-shaped body 7E, when the sphere 8 is not press-fitted into the large inner diameter portion 75, the outer diameter of at least a part of the portion corresponding to the outer circumference of the large inner diameter portion 75 corresponds to the outer diameter of the portion corresponding to the outer circumference of the small inner diameter portion 76. It is preferable that the sphere 8 is press-fitted into the large inner diameter portion 75 so that at least a part of the outer diameter and the outer diameter of the portion corresponding to the outer circumference of the small inner diameter portion 76 are equalized.

Next, a modified example of the sixth embodiment will be described with reference to FIGS. 9 (a) and 9 (b). 9 (a) shows the shaft-shaped body 7F according to the first modification of the shaft-shaped body 7E according to the sixth embodiment, and FIG. 9 (b) shows the shaft according to the sixth embodiment. The shaft-shaped body 7G according to the second modification of the state-shaped body 7E is shown. In FIGS. 9A and 9B, the axial bodies 7F and 7G are shown in axial cross sections along the central axis C, and the sphere 8 press-fitted into the shaft hole 70 is shown by a virtual line (dashed-dotted line). ing. In FIGS. 9 (a) and 9 (b), the components common to those described with reference to FIG. 8 (b) are duplicated with the same reference numerals as those attached to FIG. 8 (b). The explanation is omitted.

As shown in FIGS. 9A and 9B, the sphere 8 is press-fitted into the large inner diameter portion 75 and comes into contact with the stepped portion 77 between the large inner diameter portion 75 and the small inner diameter portion 76. Further, in the shaft-shaped body 7E according to the sixth embodiment, the case where the stepped surface 77a of the stepped portion 77 is an annular plane perpendicular to the axial direction has been described, but the shaft according to the first modification has been described. In the shape 7F, the stepped surface 77b is a tapered inclined surface inclined with respect to the axial direction. In the axial cross section shown in FIG. 9A, the stepped surface 77b is shown as a linear diagonal line, and the sphere 8 is annular at the corner between the stepped surface 77b and the inner peripheral surface 76a of the small inner diameter portion 76. It is in contact. It should be noted that the stepped surface 77b may be gently inclined with respect to the axial direction so that the sphere 8 is brought into contact with the stepped surface 77b in an annular shape.

In the shaft-shaped body 7G according to the second modification, the stepped surface 77c has a partially spherical shape having a radius of curvature corresponding to the radius of the sphere 8 (half of the diameter D2). In the axial cross section shown in FIG. 9B, the stepped surface 77c is shown in an arc shape, and the sphere 8 is in annular contact with the stepped surface 77c. The radius of curvature of the stepped surface 77c may be smaller than the radius of the sphere 8. In this case, the sphere 8 abuts in an annular shape on the corner portion between the stepped surface 77c and the inner peripheral surface 76a of the small inner diameter portion 76.

(Additional note)
Although the present invention has been described above based on the first to sixth embodiments, these embodiments do not limit the invention according to the claims. It should also be noted that not all combinations of features described in the embodiments are essential to the means for solving the problems of the invention.

Further, the present invention can be appropriately modified and implemented by omitting a part of the configuration or adding or replacing the configuration within a range not deviating from the gist thereof. It is also possible to combine the configurations shown in the first to fifth embodiments.

1 ... Planetary gear device 2 ... External gear 21 ... External tooth 3 ... Internal gear 31 ... Internal tooth 4 ... Planetary gear (rotary body)
5 ... Roller bearing 51 ... Needle roller (rolling element)
6 ... Carriers 61, 61A to 61D ... Support shaft 621a ... Fitting hole 621b ... Inner peripheral surface 7,7A to 7D ... Shaft-shaped body 70 ... Shaft hole 71 ... Introduction hole 72 ... Derivation hole 74 ... Recessed 741 ... Corner 7a ... Shaft end surface 7c ... Inner peripheral surface 7d ... Outer peripheral surface 8 ... Sphere

Claims (9)

A rotating body support shaft that supports a rotating body via a bearing having a plurality of rolling elements.
A shaft-shaped body having a shaft hole opened on the shaft end surface and a sphere press-fitted into the shaft hole are provided.
The shaft-shaped body is formed with an introduction hole for introducing lubricating oil into the shaft hole and a lead-out hole for drawing out the lubricating oil introduced into the shaft hole toward the bearing, and the introduction in the shaft hole. The sphere is fitted and fixed to the shaft end surface side of the hole and the lead-out hole.
Rotating body support shaft. The shaft-shaped body has an annular recess formed on the inner peripheral surface of the shaft hole on the shaft end surface side of the introduction hole and the lead-out hole, and the sphere is arranged in the recess.
The recess is formed so as to be recessed radially outward from the inner peripheral surface of the shaft hole whose inner diameter is smaller than the diameter of the sphere.
The rotating body support shaft according to claim 1. The inner diameter of the recess is a dimension without a tightening margin with respect to the diameter of the sphere.
The rotating body support shaft according to claim 2. The corners at the axial ends of the recess are in contact with the sphere.
The rotating body support shaft according to claim 2 or 3. The recess is formed in an arc shape in the axial cross section of the shaft-shaped body.
The rotating body support shaft according to any one of claims 2 to 4. The sphere is press-fitted into the shaft hole from the shaft end face toward the recess.
The axial body has an outer diameter of at least a part thereof and a portion through which the sphere does not pass during the press-fitting by expanding the diameter of at least a part of the axial range through which the sphere passes during the press-fitting. The outer diameter is equalized,
The rotating body support shaft according to any one of claims 1 to 5. The shaft-shaped body has a large inner diameter portion that opens to the shaft end surface and a small inner diameter portion whose inner diameter is smaller than that of the large inner diameter portion.
The sphere is press-fitted into the large inner diameter portion and is in contact with the step portion between the large inner diameter portion and the small inner diameter portion.
The rotating body support shaft according to claim 1. A sun gear having an external tooth, an internal gear having an internal tooth, a planetary gear arranged between the sun gear and the internal gear and meshing with the external tooth and the internal tooth, and inserted into the planetary gear. It is provided with a rotating body support shaft, a bearing having a plurality of rolling elements interposed between the planetary gear and the rotating body support shaft, and a carrier to which one end of the rotating body support shaft is fixed. It ’s a planetary gear device,
The rotating body support shaft is the rotating body support shaft according to any one of claims 1 to 7.
Planetary gear device. The carrier is formed with a fitting hole into which one end of the rotating body support shaft is fitted, and an outer peripheral surface of the shaft-shaped body whose diameter is expanded by press-fitting the sphere into the shaft hole is formed. It is tightly fitted to the inner peripheral surface of the fitting hole.
The planetary gear device according to claim 8.

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