JP7354900B2 - differential gear mechanism - Google Patents

Description

The present disclosure relates to a differential gear mechanism that includes a pair of face gears and a plurality of pinion gears that mesh with the pair of face gears.

Conventionally, a differential case rotates by drive torque transmitted from a prime mover, a pinion shaft extends radially across the differential case and rotates integrally with the differential case, and is rotatably supported by the pinion shaft. A differential device is known that includes a pair of inner pinion gears, a pair of outer diameter pinion gears rotatably supported by the pinion shaft, and a pair of side gears that mesh with the pair of inner pinion gears and the pair of outer pinion gears (for example, , see Patent Document 1). In this differential device, the pair of side gears each include an inner meshing portion that meshes with the pair of inner pinion gears, and an outer meshing portion that meshes with the pair of outer pinion gears. Further, each inner pinion gear and each outer pinion gear mesh with the inner meshing portion or the outer meshing portion with different pitch circle diameters. Furthermore, the gear ratio between the inner pinion gear and the inner meshing portion and the gear ratio between the outer pinion gear and the outer meshing portion are determined to be the same. Thereby, it becomes possible to support four or more pinion gears without increasing the number of pinion shafts, and the number of parts of the differential device can be reduced and the weight can be reduced.

Japanese Patent Application Publication No. 2007-192327

However, in the conventional differential device described above, as the pitch diameter of the inner pinion gear disposed on the inner circumferential side of the side gear becomes smaller, the root diameter of the inner pinion gear also becomes smaller, and the inner circumference supported by the pinion shaft becomes smaller. It becomes difficult to ensure a sufficient wall thickness of the inner pinion gear from the surface to the bottom surface of the tooth. For this reason, in the above-mentioned conventional differential device, there is a risk that the strength, that is, the durability of the inner pinion gear and the entire device may be reduced. On the other hand, in the differential device described above, if the wall thickness from the inner circumferential surface of the inner pinion gear to the bottom surface of the tooth is sufficiently ensured, the axial length (thickness in the axial direction) of each side gear will have to be increased, and the differential device will become larger. I end up.

Therefore, the main purpose of the present disclosure is to improve durability while making a differential gear mechanism including a pair of face gears and a plurality of pinion gears meshing with the pair of face gears more compact.

The differential gear mechanism of the present disclosure includes a pair of face gears each including a plurality of inner gear teeth formed on an inner circumferential side and a plurality of outer gear teeth formed on an outer circumferential side of the plurality of inner gear teeth. , a pair of inner pinion gears meshing with the plurality of inner gear teeth of the pair of face gears, and a pair of inner pinion gears supported coaxially with the pair of inner pinion gears and meshing with the plurality of outer gear teeth of the pair of face gears. and an outer pinion gear, the plurality of outer gear teeth obtained by dividing the number of teeth of the plurality of outer gear teeth by the number of teeth of the outer pinion gear and each of the pair of outer pinion gears. The gear ratio is larger than the gear ratio of the plurality of inner gear teeth and each of the pair of inner pinion gears obtained by dividing the number of teeth of the plurality of inner gear teeth by the number of teeth of the inner pinion gear. .

In the differential gear mechanism of the present disclosure, the gear ratio between the plurality of outer gear teeth and each of the pair of outer pinion gears is set to be larger than the gear ratio between each of the plurality of inner gear teeth and the pair of inner pinion gears. This makes it possible to suppress the pitch circle diameter of each inner pinion gear from becoming smaller, suppressing an increase in the axial length (thickness) of each face gear, and increasing the distance from the inner peripheral surface of each inner pinion gear to the tooth bottom surface. Good wall thickness can be ensured. As a result, it is possible to make the differential gear mechanism more compact and to improve the strength, that is, the durability, of the inner pinion gear and of the entire differential gear mechanism.

FIG. 2 is a perspective view showing a differential gear mechanism of the present disclosure. FIG. 2 is a partial cross-sectional view showing the differential gear mechanism of the present disclosure. FIG. 3 is a perspective view showing another differential gear mechanism of the present disclosure. FIG. 3 is a partial cross-sectional view showing another differential gear mechanism of the present disclosure.

Next, embodiments for carrying out the invention of the present disclosure will be described with reference to the drawings.

FIG. 1 is a perspective view showing a differential gear mechanism 1 of the present disclosure, and FIG. 2 is a partial sectional view showing the differential gear mechanism 1. The differential gear mechanism 1 shown in these drawings is included in a differential gear mounted on a vehicle together with a differential ring gear, a differential case, etc. that are not shown. The differential gear mechanism 1 includes a pair of face gears (crown gears) 2 arranged coaxially, a pair (two) of inner pinion gears 3 that mesh with the pair of face gears 2, and a pair of inner pinion gears 3 that mesh with the pair of face gears 2, respectively. It includes a pair (two) of outer pinion gears 4 that mesh with each other. A pinion shaft 5 supported by the differential case is inserted into each inner pinion gear 3 and each outer pinion gear 4 so as to be perpendicular to the axes 2c of the pair of face gears 2. Thereby, each inner pinion gear 3 and each outer pinion gear 4 are coaxially and rotatably supported by the differential case via the pinion shaft 5.

The pair of face gears 2 are fixed to a drive shaft (not shown) and function as side gears of a differential gear. Each face gear 2 includes a shaft hole 2o to which a drive shaft is fixed, a plurality of inner gear teeth 21 on the inner peripheral side that mesh with each inner pinion gear 3, and a plurality of inner gear teeth 21 located between adjacent inner gear teeth 21. The inner tooth bottom surface 24 , the plurality of outer gear teeth 25 formed on the outer peripheral side of the plurality of inner gear teeth 21 and meshing with each outer pinion gear 4 , and the plurality of outer gear teeth located between each adjacent outer gear tooth 25 . The tooth bottom surface 28 is included. In each face gear 2, the number of teeth of the outer gear teeth 25 is greater than the number of teeth of the inner gear teeth 21. In this embodiment, the number of teeth of the inner gear teeth 21 is 20, and the number of teeth of the outer gear teeth 25 is greater than the number of teeth of the inner gear teeth 21. The number is 26.

Each inner gear tooth 21 includes a pair of tooth surfaces 22 created using the tooth surfaces of the inner pinion gear 3, and an inner tooth tip surface 23 that is a flat surface or a convex curved surface formed between the pair of tooth surfaces 22. including. As shown in FIG. 2, the inner tooth tip surface 23 of each inner gear tooth 21 approaches the inner tooth bottom surface 24 as it goes from the axis 2c side (inner circumferential side) of the face gear 2 toward the outer circumferential side of the face gear 2. It includes an inclined portion 23s that is inclined so as to be inclined. Each outer gear tooth 25 includes a pair of tooth surfaces 26 created using the tooth surfaces of the outer pinion gear 4, and an outer tooth tip surface 27 that is a flat surface or a convex curved surface formed between the pair of tooth surfaces 26. including. As shown in FIG. 2, the outer tooth tip surface 27 of each outer gear tooth 25 approaches the outer tooth bottom surface 28 as it goes from the axis 2c side (inner circumferential side) of the face gear 2 toward the outer circumferential side of the face gear 2. It includes an inclined portion 27s that is inclined so as to be inclined.

Each inner pinion gear 3 includes a pinion shaft hole 3o (see FIG. 2) into which the pinion shaft 5 is inserted, and a plurality of pinion teeth 30 each having a tooth trace extending parallel to the axis 3c (see FIG. 2). The spur gear includes a plurality of pinion tooth bottom surfaces 35 located between adjacent pinion teeth 30, respectively. In this embodiment, each pinion tooth 30 includes a pair of tooth surfaces 31 formed by, for example, an involute curve, and a pinion tooth formed so as to extend parallel to the axis 3c between the pair of tooth surfaces 31. The tooth tip 32 is included. Further, as shown in FIG. 2, each pinion tooth bottom surface 35 of the inner pinion gear 3 is inclined so as to approach the pinion tooth tip 32 as it goes from the axis 2c side (inner circumferential side) of the face gear 2 toward the outer circumferential side. It includes a slope portion 35s.

As a result, as shown in FIG. 2, the distance (thickness) between each pinion tooth bottom surface 35 and the inner peripheral surface of the pinion shaft hole 3o (inner pinion gear 3) is on the axis 2c side (inner peripheral side) of the face gear 2. It increases toward the outer circumferential side of the face gear 2. Further, when the pinion tooth bottom surface 35 is viewed in plan, the pinion tooth bottom surface 35 narrows from the outer circumferential side of the face gear 2 toward the axis 2c side (inner circumferential side) of the face gear 2.

Each outer pinion gear 4 includes a pinion shaft hole 4o (see FIG. 2) into which the pinion shaft 5 is inserted, and a plurality of pinion teeth 40 each having a tooth trace extending parallel to the axis 4c (see FIG. 2). The spur gear includes a plurality of pinion tooth bottom surfaces 45 located between adjacent pinion teeth 40, respectively. In this embodiment, each pinion tooth 40 includes a pair of tooth surfaces 41 formed by, for example, an involute curve, and a pinion tooth formed so as to extend parallel to the axis 4c between the pair of tooth surfaces 41. The tooth tip 42 is included. Further, as shown in FIG. 2, each pinion tooth bottom surface 45 of the outer pinion gear 4 is inclined so as to approach the pinion tooth tip 42 as it goes from the axis 2c side (inner circumferential side) of the face gear 2 toward the outer circumferential side. It includes a slope portion 45s.

As a result, as shown in FIG. 2, the distance (thickness) between each pinion tooth bottom surface 45 and the inner peripheral surface of the pinion shaft hole 4o (outer pinion gear 4) is on the axis 2c side (inner peripheral side) of the face gear 2. It increases toward the outer circumferential side of the face gear 2. Further, when the pinion tooth bottom surface 45 is viewed in plan, the pinion tooth bottom surface 45 narrows from the outer circumferential side of the face gear 2 toward the axis 2c side (inner circumferential side) of the face gear 2.

In addition, the inner pinion gear 3 and the outer pinion gear 4 have the same number of teeth. In this embodiment, the number of teeth of the inner pinion gear 3 and the number of teeth of the outer pinion gear 4 are both nine. The gear ratio Gi between the plurality of inner gear teeth 21 of the face gear 2 and each of the pair of inner pinion gears 3 is obtained by dividing the number of teeth of the inner gear teeth 21 by the number of teeth of the inner pinion gear 3. The gear ratio Go between the plurality of outer gear teeth 25 and each of the pair of outer pinion gears 4 is obtained by dividing the number of teeth of the outer gear teeth 25 by the number of teeth of the outer pinion gear 4. As a result, the gear ratio Go between the plurality of outer gear teeth 25 and each outer pinion gear 4 (in this embodiment, Go=26/9) becomes the gear ratio Gi (between the plurality of inner gear teeth 21 and each inner pinion gear 3) ( In this embodiment, Go=20/9). Note that the line segment L1 in FIG. 2 indicates the rolling pitch conical line between the plurality of inner gear teeth 21 of the face gear 2 and each inner pinion gear 3, and the line segment L2 indicates the rolling pitch conical line between the plurality of inner gear teeth 21 of the face gear 2 and each inner pinion gear 3. The rolling pitch cone line with each outer pinion gear 4 is shown.

Furthermore, as shown in FIG. 2, the pitch circle diameter Dpi of the inner pinion gear 3 is the same as the pitch circle diameter Dpo of the outer pinion gear 4, and the tip circle diameter Dti of the inner pinion gear 3 is the same as the tip circle of the outer pinion gear 4. It is the same as the diameter Dto. In this embodiment, the minimum value of the root diameter of the inner pinion gear 3 is the same as the minimum value of the root diameter of the outer pinion gear 4, and the maximum value of the root diameter of the inner pinion gear 3 is the same as the minimum value of the root diameter of the outer pinion gear 4. It is the same as the maximum value of the root diameter of the pinion gear 4.

As described above, in the differential gear mechanism 1, the gear ratio Go between the plurality of outer gear teeth 25 of the face gear 2 and each of the pair of outer pinion gears 4 is the same as that of the plurality of inner gear teeth 21 of the face gear 2 and the pair of outer gear teeth 21. It is determined to be larger than the gear ratio Gi of each of the inner pinion gears 3. This makes it possible to suppress the pitch circle diameter Dpi of each inner pinion gear 3 from becoming smaller, and while suppressing an increase in the axial length (thickness) of each face gear 2, as shown in FIG. A good thickness can be ensured from the inner circumferential surface of the pinion gear 3 (inner circumferential surface of the pinion shaft hole 3o) to the pinion tooth bottom surface 35. As a result, it is possible to make the differential gear mechanism 1 more compact and to improve the strength, that is, the durability, of each inner pinion gear 3 and of the entire differential gear mechanism 1.

Further, in the differential gear mechanism 1, the pitch diameter Dpi of each inner pinion gear 3 is the same as the pitch diameter Dpo of each outer pinion gear 4, and the tip diameter Dti of each inner pinion gear 3 is the same as the pitch diameter Dpo of each outer pinion gear 4. It is assumed to be the same as the tip circle diameter Dto of No. 4. As a result, while ensuring the strength of each inner pinion gear 3 and each outer pinion gear 4, the increase in the axial length of each face gear 2 and the length of the differential gear mechanism 1 in the axial direction of the face gear 2 can be suppressed. It becomes possible to do so. However, if the strength of each inner pinion gear 3 is ensured, the pitch circle diameter Dpi of each inner pinion gear 3 does not necessarily have to match the pitch circle diameter Dpo of each outer pinion gear 4, and each inner pinion gear 3 The tip diameter Dti of each outer pinion gear 4 does not necessarily have to match the tip diameter Dto of each outer pinion gear 4.

Further, in each face gear 2, the inner tooth tip surface 23 of each of the plurality of inner gear teeth 21 is inclined so as to approach the inner tooth bottom surface 24 as it goes from the axis 2c side of the face gear 2 toward the outer circumferential side. The outer tooth top surface 27 of each of the plurality of outer gear teeth 25 has an inclined portion 27s that is inclined so as to approach the outer tooth bottom surface 28 as it goes from the axis 2c side of the face gear 2 toward the outer circumferential side. include. Further, each of the pinion tooth bottom surfaces 35 located between adjacent pinion teeth 30 of the inner pinion gear 3 is inclined so as to approach the pinion tooth tip 32 as it goes from the axis 2c side of the face gear 2 toward the outer circumferential side. 35s. Furthermore, each of the pinion tooth bottom surfaces 45 located between adjacent pinion teeth 40 of the outer pinion gear 4 is inclined so as to approach the pinion tooth tip 42 from the axis 2c side of the face gear 2 toward the outer circumferential side. 45s.

As a result, the wall thickness from the inner circumferential surface of each inner pinion gear 3 and each outer pinion gear 4 (inner circumferential surface of pinion shaft holes 3o, 4o) to the pinion tooth bottom surfaces 35, 45 is ensured well, and the inner pinion gear 3 and each outer pinion gear 4 are It becomes possible to improve the strength of the outer pinion gear 4 and, by extension, the entire differential gear mechanism 1. However, from each inner tooth top surface 23 and each outer tooth top surface 27 of each face gear 2, each pinion tooth bottom surface 35 of each inner pinion gear 3, and each pinion tooth bottom surface 45 of each outer pinion gear 4, the inclined portions 23s, 27s, 35s or 45s may be omitted. That is, the tip circle diameter of each inner gear tooth 21 and each outer gear tooth 25 of each face gear 2 may be determined to be constant, and the root diameter of each pinion tooth bottom surface 35 of each inner pinion gear 3 and The root diameter of each pinion tooth root surface 45 of each outer pinion gear 4 may be determined to be constant.

FIG. 3 is a perspective view showing another differential gear mechanism 1B of the present disclosure, and FIG. 4 is a partial sectional view showing the differential gear mechanism 1B. It should be noted that among the constituent elements of the differential gear mechanism 1B, the same elements as those in the above-described differential gear mechanism 1 are given the same reference numerals, and redundant explanation will be omitted.

In each face gear 2B of the differential gear mechanism 1B shown in FIGS. 3 and 4, the number of inner gear teeth 21B and the number of outer gear teeth 25B are determined to be the same. In the example of FIGS. 3 and 4, the number of teeth of the inner gear teeth 21B and the number of teeth of the outer gear teeth 25B are 26. Further, in the differential gear mechanism 1B, the outer pinion gear 4B has fewer teeth than the inner pinion gear 3B. In the example of FIGS. 3 and 4, the number of teeth of the inner pinion gear 3B is 12, and the number of teeth of the outer pinion gear 4B is 9.

Also in this differential gear mechanism 1B, the gear ratio Go between the plurality of outer gear teeth 25B and each of the pair of outer pinion gears 4B (Go=number of teeth of outer gear teeth 25B/number of teeth of outer pinion gear 4B=26/9) is larger than the gear ratio Gi between the plurality of inner gear teeth 21B and each of the pair of inner pinion gears 3B (Gi=number of teeth of inner gear teeth 21B/number of teeth of inner pinion gear 3B=26/12). As a result, it is possible to suppress the pitch circle diameter Dpi of each inner pinion gear 3B from becoming smaller, and while suppressing an increase in the axial length (thickness) of each face gear 2B, as shown in FIG. A good thickness can be ensured from the inner circumferential surface of the pinion gear 3B (inner circumferential surface of the pinion shaft hole 3o) to the pinion tooth bottom surface 35. As a result, it is possible to make the differential gear mechanism 1B more compact and to improve the strength, that is, the durability, of each inner pinion gear 3B and, ultimately, of the entire differential gear mechanism 1B. Furthermore, in the differential gear mechanism 1B, the manufacturing cost of the face gear 2 can be suppressed by making the number of inner gear teeth 21B and the number of outer gear teeth 25B the same.

Further, in the differential gear mechanism 1B, the pitch circle diameter Dpi of each inner pinion gear 3B is the same as the pitch circle diameter Dpo of each outer pinion gear 4B, and the tip circle diameter Dti of each inner pinion gear 3B is the same as each outer pinion gear 3B. It is set to be the same as the tooth tip circle diameter Dto of the pinion gear 4B. As a result, while ensuring the strength of each inner pinion gear 3B and each outer pinion gear 4B, the increase in the axial length of each face gear 2B and the length of the differential gear mechanism 1B in the axial direction of the face gear 2B is well suppressed. It becomes possible to do so. However, if the strength of each inner pinion gear 3B is ensured, the pitch circle diameter Dpi of each inner pinion gear 3B does not necessarily have to match the pitch circle diameter Dpo of each outer pinion gear 4B, and each inner pinion gear 3B The tip circle diameter Dti does not necessarily need to match the tip circle diameter Dto of each outer pinion gear 4B.

Furthermore, in each face gear 2B, the inner tooth tip surface 23 of each of the plurality of inner gear teeth 21B is inclined so as to approach the inner tooth bottom surface 24 as it goes from the axis 2c side of the face gear 2B toward the outer circumferential side. The outer tooth top surface 27 of each of the plurality of outer gear teeth 25B includes an inclined portion 23s that is inclined so as to approach the outer tooth bottom surface 28 from the axis 2c side of the face gear 2B toward the outer circumferential side. including. Further, each of the pinion tooth bottom surfaces 35 located between adjacent pinion teeth 30 of the inner pinion gear 3B is inclined so as to approach the pinion tooth tip 32 as it goes from the axis 2c side of the face gear 2B toward the outer circumferential side. 35s. Further, each of the pinion tooth bottom surfaces 45 located between adjacent pinion teeth 40 of the outer pinion gear 4B is inclined so as to approach the pinion tooth tip 42 as it goes from the axis 2c side of the face gear 2 toward the outer circumferential side. 45s. In the differential gear mechanism 1B, the minimum value of the root diameter of the inner pinion gear 3B is the same as the minimum value of the root diameter of the outer pinion gear 4B, and the maximum value of the root diameter of the inner pinion gear 3B is , is the same as the maximum value of the root diameter of the outer pinion gear 4B.

As a result, the wall thickness from the inner circumferential surface of each inner pinion gear 3B and each outer pinion gear 4B (inner circumferential surface of pinion shaft holes 3o, 4o) to the pinion tooth bottom surfaces 35, 45 is ensured well, and the inner pinion gear 3B and each outer pinion gear 4B are It becomes possible to improve the strength of the outer pinion gear 4B and thus of the entire differential gear mechanism 1B. However, from each inner tooth top surface 23 and each outer tooth top surface 27 of each face gear 2B, each pinion tooth bottom surface 35 of each inner pinion gear 3B, and each pinion tooth bottom surface 45 of each outer pinion gear 4B, inclined portions 23s, 27s, 35s or 45s may be omitted. That is, the tip circle diameter of each inner gear tooth 21B and each outer gear tooth 25B of each face gear 2B may be determined to be constant, and the root diameter of each pinion tooth bottom surface 35 of each inner pinion gear 3B and The root diameter of each pinion tooth root surface 45 of each outer pinion gear 4B may be determined to be constant.

The differential gear mechanisms 1 and 1B described above include a pair of inner pinion gears 3 and 3B and a pair of outer pinion gears 4 and 4B, but are not limited to this. That is, the differential gear mechanisms 1 and 1B may each include two or more pairs of inner pinion gears 3 and 3B and outer pinion gears 4 and 4B.

As described above, the differential gear mechanism of the present disclosure includes a plurality of inner gear teeth (21, 21B) formed on the inner peripheral side and a plurality of inner gear teeth (21, 21B) formed on the outer peripheral side of the plurality of inner gear teeth (21, 21B). a pair of face gears (2, 2B) each including a plurality of outer gear teeth (25, 25B), and a plurality of inner gear teeth (21, 21B) of the pair of face gears (2, 2B); a pair of inner pinion gears (3, 3B) that mesh with each other; and a plurality of outer gear teeth (25, In a differential gear mechanism (1, 1B) including a pair of outer pinion gears (4, 4B) meshing with the outer pinion gears (4, 4B), the number of teeth of the plurality of outer gear teeth (25, 25B) is The gear ratio (Go) between the plurality of outer gear teeth (25, 25B) and each of the pair of outer pinion gears (4, 4B) obtained by dividing by the number of teeth of the plurality of inner gear teeth ( The plurality of inner gear teeth (21, 21B) obtained by dividing the number of teeth of the inner pinion gear (21, 21B) by the number of teeth of the inner pinion gear (3, 3B) and each of the pair of inner pinion gears (3, 3B). This is larger than the gear ratio (Gi) of .

In the differential gear mechanism of the present disclosure, the gear ratio between the plurality of outer gear teeth and each of the pair of outer pinion gears is set to be larger than the gear ratio between each of the plurality of inner gear teeth and the pair of inner pinion gears. This makes it possible to suppress the pitch circle diameter of each inner pinion gear from becoming smaller, suppressing an increase in the axial length (thickness) of each face gear, and increasing the distance from the inner peripheral surface of each inner pinion gear to the tooth bottom surface. Good wall thickness can be ensured. As a result, it is possible to make the differential gear mechanism more compact and to improve the strength, that is, the durability, of the inner pinion gear and of the entire differential gear mechanism.

Further, the pitch circle diameter (Dpi) of the inner pinion gear (3, 3B) is the same as the pitch circle diameter (Dpo) of the outer pinion gear (4, 4B), and the tooth tip of the inner pinion gear (3, 3B) The circular diameter (Dti) may be the same as the tip circular diameter (Dto) of the outer pinion gear (4, 4B). As a result, it is possible to satisfactorily suppress increases in the axial length of each face gear and the length of the differential gear mechanism 1 in the axial direction of the face gear 2 while ensuring good strength of the inner pinion gear and the outer pinion gear. Become.

Further, the tooth top surface (23) of each of the plurality of inner gear teeth (21, 21B) becomes a tooth bottom surface (24) as it goes from the axis (2c) side of the face gear (2, 2B) toward the outer peripheral side. The tooth tip surface (27) of each of the plurality of outer gear teeth (25, 25B) may include an inclined portion (23s) inclined so as to approach the axis of the face gear (2, 2B). It may include an inclined part (27s) which is inclined so as to approach the tooth bottom surface (28) from the side (2c) toward the outer circumferential side, and between adjacent pinion teeth (30) of the inner pinion gears (3, 3B). Each of the pinion tooth bottom surfaces (35) located in the face gear (2, 2B) is inclined so as to approach the pinion tooth tip (32) from the axis (2c) side toward the outer peripheral side. Each of the pinion tooth bottom surfaces (45) located between adjacent pinion teeth (40) of the outer pinion gears (4, 4B) may include a portion (35s) of the face gear (2, 2B). It may include an inclined part (45s) which is inclined so as to approach the pinion tooth tip (42) from the axis (2c) side toward the outer peripheral side. As a result, it is possible to ensure a good wall thickness from the inner peripheral surface to the bottom surface of each inner pinion gear and each outer pinion gear, and to improve the strength of the inner pinion gear and outer pinion gear, as well as the entire differential gear mechanism.

Furthermore, the number of teeth of the outer pinion gear (4) may be the same as the number of teeth of the inner pinion gear (3), and the number of teeth of the outer gear teeth (25) may be the same as the number of teeth of the inner gear teeth (21). There may be more than the number of teeth. This makes it possible to make the gear ratio between the plurality of outer gear teeth and each outer pinion gear larger than the gear ratio between the plurality of inner gear teeth and each inner pinion gear, while ensuring good strength of the inner pinion gear and the outer pinion gear. It becomes possible.

Further, the number of teeth of the outer pinion gear (3B) may be smaller than the number of teeth of the inner pinion gear (4B), and the number of teeth of the outer gear teeth (25B) is smaller than the number of teeth of the inner gear teeth (21B). It may be the same as the number. This makes it possible to make the gear ratio between the plurality of outer gear teeth and each outer pinion gear larger than the gear ratio between the plurality of inner gear teeth and each inner pinion gear, while suppressing the processing cost of the face gear.

Furthermore, the differential gear mechanism (1, 1B) may be included in a differential gear mounted on a vehicle.

It goes without saying that the invention of the present disclosure is not limited to the above-described embodiments, and that various changes can be made within the scope of the present disclosure. Further, the above-described embodiment is merely one specific form of the invention described in the Summary of the Invention column, and does not limit the elements of the invention described in the Summary of the Invention column.

The invention disclosed herein can be used in the field of manufacturing differential gear mechanisms, etc.

1, 1B differential gear mechanism, 2, 2B face gear, 2c shaft center, 2o shaft hole, 21, 21B inner gear tooth, 22 tooth surface, 23 inner tooth top surface, 23s inclined part, 24 inner tooth bottom surface, 25, 25B outer gear tooth, 26 tooth surface, 27 outer tooth top surface, 27s slope, 28 outer tooth bottom surface, 3, 3B inner pinion gear, 3c shaft center, 3o pinion shaft hole, 30 pinion tooth, 31 tooth surface, 32 pinion tooth Tip, 35 Pinion tooth bottom surface, 35s Inclined portion, 4, 4B Outer pinion gear, 4c Axis center, 4o Pinion shaft hole 5 Pinion shaft, 40 Pinion tooth, 41 Tooth surface, 42 Pinion tooth tip, 45 Pinion tooth bottom surface, 45s Inclined portion .

Claims (6)

a pair of face gears each including a plurality of inner gear teeth formed on an inner peripheral side and a plurality of outer gear teeth formed on an outer peripheral side of the plurality of inner gear teeth; and the plurality of face gears of the pair of face gears. A differential gear including a pair of inner pinion gears that mesh with inner gear teeth of the pair of inner pinion gears, and a pair of outer pinion gears that are coaxially supported with the pair of inner pinion gears and mesh with the plurality of outer gear teeth of the pair of face gears. In the mechanism,
The gear ratio between the plurality of outer gear teeth and each of the pair of outer pinion gears, which is obtained by dividing the number of teeth of the plurality of outer gear teeth by the number of teeth of the outer pinion gear, is the number of teeth of the plurality of inner gear teeth. The differential gear mechanism has a gear ratio greater than a gear ratio between the plurality of inner gear teeth and each of the pair of inner pinion gears obtained by dividing the number by the number of teeth of the inner pinion gear. The differential gear mechanism according to claim 1,
The pitch circle diameter of the inner pinion gear is the same as the pitch circle diameter of the outer pinion gear, and the tip circle diameter of the inner pinion gear is the same as the tip circle diameter of the outer pinion gear. The differential gear mechanism according to claim 2,
The tooth tip surface of each of the plurality of inner gear teeth includes an inclined portion that is inclined so as to approach the tooth bottom surface from the axial center side of the face gear toward the outer peripheral side,
The tooth tip surface of each of the plurality of outer gear teeth includes an inclined portion that is inclined so as to approach the tooth bottom surface from the axial center side of the face gear toward the outer peripheral side,
Each of the pinion tooth bottom surfaces located between adjacent pinion teeth of the inner pinion gear includes an inclined portion that is inclined so as to approach a pinion tooth tip from the axis side of the face gear toward the outer peripheral side,
Each of the pinion tooth bottom surfaces located between adjacent pinion teeth of the outer pinion gear includes an inclined portion that is inclined so as to approach a pinion tooth tip from the axis side of the face gear toward the outer peripheral side. Moving gear mechanism. The differential gear mechanism according to any one of claims 1 to 3,
The number of teeth of the outer pinion gear is the same as the number of teeth of the inner pinion gear, and the number of teeth of the outer gear teeth is greater than the number of teeth of the inner gear tooth. The differential gear mechanism according to any one of claims 1 to 3,
The number of teeth of the outer pinion gear is smaller than the number of teeth of the inner pinion gear, and the number of teeth of the outer gear teeth is the same as the number of teeth of the inner gear teeth. The differential gear mechanism according to any one of claims 1 to 5, which is included in a differential gear mounted on a vehicle.

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