Planetary carrier

Abstract

To provide a planetary carrier excellent in abrasion resistance and quietness with respect to the sliding of a gear and a gear shaft.SOLUTION: The planetary carrier includes a plurality of pinion shaft portions into which the pinion gears are inserted, respectively, and an annular or disk-shaped shaft support portion that supports one ends of the plurality of pinion shaft portions at predetermined intervals in the circumferential direction. The plurality of pinion shaft portions are formed in a partially cylindrical shape having an arc portion of a semicircle or more when viewed in the axial direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This specification discloses a planetary carrier. [Background technology]

[0002] A planetary gear reduction mechanism has been proposed in the past (see, for example, Patent Document 1), which includes a sun gear with external teeth, an internal gear with internal teeth arranged concentrically with the sun gear, multiple planetary gears meshing with the sun gear and the internal gear, and a carrier supporting the multiple planetary gears so that they can rotate and revolve around their axes. The carrier has multiple cylindrical pins that are spaced apart along the circumferential direction, and the planetary gears are inserted into the multiple pins, thereby supporting the planetary gears rotatably. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2021 / 215156 Summary of the Invention [Problem to be solved by the invention]

[0004] In a planetary carrier that supports a planetary gear (pinion gear) with a cylindrical pin (pinion shaft portion), wear and noise can become a problem due to sliding between the pinion shaft portion and the pinion gear.

[0005] A primary object of the present disclosure is to provide a planetary carrier that is excellent in wear resistance and quietness with respect to sliding between a pinion shaft portion and a pinion gear. [Means for solving the problem]

[0006] The present disclosure has adopted the following means to achieve the above-mentioned main object.

[0007] The planetary carrier of the present disclosure comprises a plurality of pinion shaft portions through which pinion gears are respectively inserted, and annular or disk-shaped shaft support portions that support one end of the plurality of pinion shaft portions at a predetermined interval in the circumferential direction, and the plurality of pinion shaft portions are formed in a partially cylindrical shape having an arc portion that is equal to or greater than a semicircle when viewed in the axial direction.

[0008] In the planetary carrier disclosed herein, the pinion shaft portions through which the pinion gears are inserted are formed in a partially cylindrical shape with an arc portion that is equal to or greater than a semicircle when viewed in the axial direction, which prevents backlash between the pinion gears and the pinion shaft portions and allows lubricant (grease, etc.) to be held in the notched portions of the pinion shaft portions. As a result, the planetary carrier has excellent wear resistance and quietness against sliding between the pinion gears and the pinion shaft portions. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a perspective view of a planetary carrier according to the present embodiment. [Figure 2] 5A to 5C are explanatory views showing a manufacturing process of the planetary carrier according to the embodiment. [Figure 3] FIG. 10 is a perspective view of a planetary carrier according to another embodiment. [Figure 4] FIG. 4 is an explanatory diagram showing a vertical load acting on a pinion shaft portion. DETAILED DESCRIPTION OF THE INVENTION

[0010] Next, embodiments of the present disclosure will be described with reference to the drawings.

[0011] FIG. 1 is a perspective view of a planetary carrier 10 of this embodiment. The planetary carrier 10 of this embodiment is a component of a single-pinion planetary gear applied to a reducer. The single-pinion planetary gear has a sun gear with external teeth, an internal gear (ring gear) with internal teeth arranged concentrically with the sun gear, multiple pinion gears meshed with the sun gear and the internal gear, and a planetary carrier that supports the multiple pinion gears so that they can rotate and revolve. Note that planetary gears are not limited to those applied to reducers, and may also be applied to automatic transmissions.

[0012] As shown in Fig. 1, the planetary carrier 10 of this embodiment integrally includes a plurality of (e.g., three) pinion shaft portions 11, a shaft support portion 12, and an output gear portion 13. A pinion gear of a planetary gear is rotatably inserted into the pinion shaft portion 11. The shaft support portion 12 is formed in a disk shape and supports one end of the plurality of pinion shaft portions 11 so that they are arranged at regular intervals along the circumferential direction. The output gear portion 13 is an output gear of the reducer, and is formed coaxially with the center of the shaft support portion 12 on the surface of the shaft support portion 12 opposite to the support surface of the pinion shaft portion 11.

[0013] 1, each pinion shaft portion 11 of the planetary carrier 10 of this embodiment has a notch portion 11a formed on the radially outer side as viewed from the center of the shaft support portion 12. That is, when viewed in the axial direction, the pinion shaft portion 11 is formed in a partially cylindrical shape having an arc portion of at least a semicircle on the radially inner side as viewed from the center of the shaft support portion 12. Then, by inserting a pinion gear into the pinion shaft portion 11 of the planetary carrier 10 and filling a lubricant (grease) into the notch portion 11a of the pinion shaft portion 11 and assembling them as a planetary gear, the lubricant can be well retained in the notch portion 11a, and a planetary gear with excellent wear resistance and quietness due to sliding between the pinion gear and the pinion shaft portion 11 can be obtained.

[0014] Next, a manufacturing process for the planetary carrier 10 will be described. Fig. 2 is an explanatory diagram showing an example of the manufacturing process for the planetary carrier 10. In the manufacturing process for the planetary carrier 10, first, a bar material is prepared (S100), and the prepared bar material is processed by forging (S110), and then formed into the outer shape of the finished product by cutting (S120). Then, finishing is performed (S130) to complete the product.

[0015] In the above-described embodiment, each pinion shaft portion 11 of the planetary carrier 10 has a notch portion 11a formed on the radially outer side as viewed from the center of the shaft support portion 12, but each pinion shaft portion 111 of a planetary carrier 110 according to another embodiment has a notch portion 111a formed on the radially inner side as viewed from the center of the shaft support portion 12, as shown in Fig. 3. That is, the pinion shaft portion 111 is formed in a partial cylindrical shape having an arc portion of at least a semicircle on the radially outer side as viewed from the center of the shaft support portion 12 when viewed in the axial direction. Then, by inserting a pinion gear into the pinion shaft portion 111 of the planetary carrier 110, filling the notch portion 111a of the pinion shaft portion 111 with lubricant (grease), and assembling them as a planetary gear, the lubricant can be well retained in the notch portion 111a, and the planetary gear can be made to have excellent wear resistance and quietness against the sliding between the pinion gear and the pinion shaft portion 111.

[0016] Here, the planetary carrier 10 of this embodiment is suitable for cases where, when assembled and operated as a planetary gear (reduction gear), a load acts on each pinion shaft portion 11 radially outward as viewed from the center of the shaft support portion 12. On the other hand, the planetary carrier 110 of another embodiment is suitable for cases where a load acts on each pinion shaft portion 111 radially inward as viewed from the center of the shaft support portion 12. As a result, the load acting on the pinion shaft portions 11, 111 can be received by the semi-cylindrical surface of the pinion shaft portions 11, 111 on the side opposite to the notched portions 11a, 111a, and sufficient load-bearing capacity can be ensured even if the notched portions 11a, 111a are formed in the pinion shaft portions 11, 111. Furthermore, since the pinion shaft portion 11, 111 has an arc portion that is equal to or greater than a semicircle when viewed in the axial direction, rattle can be prevented from occurring between the pinion shaft portion 11, 111 and the pinion gear inserted through the pinion shaft portion 11, 111.

[0017] FIG. 4 is an explanatory diagram showing the vertical load (bearing load) acting on the pinion shaft portion 11. The sun gear 2, internal gear (ring gear) 3, and pinion gear 4 of a single-pinion planetary gear 1 generally have involute tooth profiles. As shown in FIG. 4, a load Fn acts on the meshing point Ps between the sun gear 2 and pinion gear 4 in a direction tangentially away from the center of the sun gear 2, radially outward by a meshing pressure angle θ1. A load Fn also acts on the meshing point Pr between the internal gear 3 and pinion gear 4 in a direction tangentially away from the center of the internal gear 3, radially inward by a meshing pressure angle θ2. A centrifugal force Fc acts on the pinion gear 4 due to its revolution. The meshing pressure angles θ1 and θ2 are determined by the number of teeth, gear pitch, module, and tool pressure angle of each gear. Furthermore, the meshing pressure angles θ1 and θ2 are different from one another when the following equation (1) is established, where Zs is the number of teeth of the sun gear 2, Zr is the number of teeth of the internal gear (ring gear) 3, and Zp is the number of teeth of the pinion gear 4. It can be seen from FIG. 4 that the load Pb acting in the radial direction on the pinion gear 4 as viewed from the center of the sun gear 2 (the bearing load that the pinion shaft portion 11 receives in the radial direction as viewed from the shaft support portion 12) can be derived from the following equation (2). In equation (2), the radial bearing load Pb is defined as a positive value on the radially outer side. Therefore, if the radial bearing load Pb is a positive value, the planetary carrier 10 of this embodiment is used. If the radial bearing load Pb is a negative value, the planetary carrier 110 of another embodiment is used. This allows the semi-cylindrical surfaces of the pinion shaft portions 11 and 111 to bear the bearing load Pb, thereby ensuring good load-bearing capacity.

[0018] Zr = Zs + 2 · Zp + 1 …(1) Pb=Fn·sinθ1-Fn·sinθ2+Fc …(2)

[0019] The sun gear 2, internal gear (ring gear) 3, and pinion gear 4 of a single-pinion planetary gear are usually designed so that the following equation (3) holds, and therefore the meshing pressure angles θ1 and θ2 are the same. Therefore, the radial bearing load Pb is positive as shown in the following equation (4) due to the action of only the centrifugal force Fc, and therefore it is preferable to employ the planetary carrier 10 of this embodiment.

[0020] Zr = Zs + 2 Zp …(3) Pb = Fc (> 0) … (4)

[0021] In the above-described embodiment, the planetary carriers 10, 110 are provided with the output gear portion 13, but they may not be provided with the output gear portion 13. In this case, the shaft support portion 12 may be formed in an annular shape.

[0022] It goes without saying that the present disclosure is not limited to the above-described embodiments, and can be implemented in various forms as long as they fall within the technical scope of the present disclosure. [Industrial Applicability]

[0023] The present disclosure is applicable to the planetary carrier manufacturing industry and the like. [Explanation of symbols]

[0024] 10,110 Planetary carrier, 10B,110B Intermediate member, 11,111 Pinion shaft portion, 11a,111a Notched portion, 12 Shaft support portion, 14,114 Waste portion.

Claims

1. a plurality of pinion shaft portions through which pinion gears are inserted; an annular or disc-shaped shaft support portion that supports one ends of the plurality of pinion shaft portions at predetermined intervals in the circumferential direction; Equipped with The plurality of pinion shaft portions are formed in a partially cylindrical shape having an arc portion that is equal to or greater than a semicircle when viewed in the axial direction. Planetary carrier.

2. 2. The planetary carrier according to claim 1, Each of the plurality of pinion shaft portions is notched radially inward or radially outward as viewed from the center of the shaft support portion. Planetary carrier.

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