JP2021156416A - Differential gear mechanism - Google Patents

Abstract

To improve the durability of pinion gears while making a differential gear mechanism including a pair of face gears and a plurality of pinion gears engaged with the pair of face gears compact in a size.SOLUTION: A differential gear mechanism includes a pair of face gears 2, 2 including a plurality of inside gear teeth 21 formed at an internal peripheral side, and a plurality of outside gear teeth 25 formed at an external peripheral side of the plurality of inside gear teeth, a pair of inside pinion gears 3 engaged with the plurality of inside gear teeth of the pair of face gears, and a pair of outside pinion gears 4 supported to the pair of inside pinion gears coaxially therewith, and engaged with the plurality of outside gear teeth of the pair of face gears. A gear ratio of the plurality of outside gear teeth and the pair of outside pinion gears is higher than a gear ratio of the plurality of inside gear teeth and the pair of inside pinion gears.SELECTED DRAWING: Figure 1

Description

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

Conventionally, a differential case that rotates by a drive torque transmitted from a prime mover, a pinion shaft that is radially passed to the differential case and rotates integrally with the differential case, and a pinion shaft that 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 inner pinion gears and a pair of side gears that mesh with the pair of outer pinion gears (eg,). , Patent Document 1). In this differential, the pair of side gears includes 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, respectively. 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. Further, 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 defined to be the same. As a result, it is possible to support four or more pinion gears without increasing the number of pinion shafts, and it is possible to reduce the number of parts of the differential device and reduce the weight.

JP-A-2007-192327

However, in the above-mentioned conventional differential device, the diameter of the pitch circle of the inner pinion gear arranged on the inner peripheral side of the side gear becomes smaller, so that the diameter of the root circle of the inner pinion gear also becomes smaller, and the inner circumference supported by the pinion shaft. It becomes difficult to secure a sufficient wall thickness of the inner pinion gear from the surface to the bottom of the tooth. Therefore, in the above-mentioned conventional differential device, the strength of the inner pinion gear and thus the device as a whole, that is, the durability may decrease. On the other hand, in the above differential device, if a sufficient wall thickness from the inner peripheral surface of the inner pinion gear to the tooth bottom surface is secured, the axial length (thickness in the axial direction) of each side gear must be increased, and the differential device becomes larger. It ends up.

Therefore, it is a main object of the present disclosure to improve durability while compacting a differential gear mechanism including a pair of face gears and a plurality of pinion gears that mesh with the pair of face gears.

The differential gear mechanism of the present disclosure includes a pair of face gears including a plurality of inner gear teeth formed on the inner peripheral side and a plurality of outer gear teeth formed on the outer peripheral side of the plurality of inner gear teeth. A pair of inner pinion gears that mesh with the plurality of inner gear teeth of the pair of face gears, and a pair of inner 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 a differential gear mechanism including the 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 each of the plurality of inner gear teeth and 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 of the plurality of outer gear teeth and each of the pair of outer pinion gears is set to be larger than the gear ratio of the plurality of inner gear teeth and each of the pair of inner pinion gears. This makes it possible to prevent the pitch circle diameter of each inner pinion gear from becoming smaller, and while suppressing an increase in the shaft length (thickness) of each face gear, from the inner peripheral surface of each inner pinion gear to the tooth bottom surface. A good wall thickness can be secured. As a result, it is possible to improve the strength, that is, the durability of the inner pinion gear and the entire differential gear mechanism while making the differential gear mechanism compact.

It is a perspective view which shows the differential gear mechanism of this disclosure. It is a partial cross-sectional view which shows the differential gear mechanism of this disclosure. It is a perspective view which shows the other differential gear mechanism of this disclosure. It is a partial cross-sectional view which shows the other differential gear mechanism of this disclosure.

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

FIG. 1 is a perspective view showing the differential gear mechanism 1 of the present disclosure, and FIG. 2 is a partial cross-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, and the like (not shown). The differential gear mechanism 1 includes a pair of face gears (crown gears) 2 arranged coaxially, a pair of (two) inner pinion gears 3 that mesh with each other of the pair of face gears 2, and a pair of face gears 2, respectively. Includes a pair (two) outer pinion gears 4 that mesh. A pinion shaft 5 supported by a differential case is inserted into each inner pinion gear 3 and each outer pinion gear 4 so as to be orthogonal to the axis 2c of the pair of face gears 2. As a result, 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 the differential gear. Each face gear 2 has a plurality of inner gear teeth 21 located between 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 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 sides located between the adjacent outer gear teeth 25, respectively. Includes tooth bottom 28. In each face gear 2, the number of teeth of the outer gear teeth 25 is larger than the number of teeth of the inner gear teeth 21, and in the present embodiment, the number of teeth of the inner gear teeth 21 is 20, and the number of teeth of the outer gear teeth 25. The number is 26.

Each inner gear tooth 21 has a pair of tooth surfaces 22 created by using the tooth surfaces of the inner pinion gear 3 and an inner tooth tip surface 23 which is a flat surface or a convex curved surface formed between the pair of tooth surfaces 22. And include. As shown in FIG. 2, the inner tooth tip surface 23 of each inner gear tooth 21 approaches the inner tooth bottom surface 24 from the axial center 2c side (inner peripheral side) of the face gear 2 toward the outer peripheral side of the face gear 2. Includes an inclined portion 23s inclined so as to do so. Each outer gear tooth 25 has a pair of tooth surfaces 26 created by using the tooth surfaces of the outer pinion gear 4, and an outer tooth tip surface 27 which is a flat surface or a convex curved surface formed between the pair of tooth surfaces 26. And include. As shown in FIG. 2, the outer tooth tip surface 27 of each outer gear tooth 25 approaches the outer tooth bottom surface 28 from the axial center 2c side (inner peripheral side) of the face gear 2 toward the outer peripheral side of the face gear 2. Includes an inclined portion 27s inclined so as to do so.

Each inner pinion gear 3 includes a pinion shaft hole 3o through which the pinion shaft 5 is inserted (see FIG. 2), a plurality of pinion teeth 30 having tooth streaks extending parallel to the axis 3c (see FIG. 2), and a plurality of pinion teeth 30. It is a spur gear including a plurality of pinion tooth bottom surfaces 35 located between adjacent pinion teeth 30. In the present embodiment, each pinion tooth 30 is formed so as to extend in parallel with the axis 3c between a pair of tooth surfaces 31 formed by, for example, an involute curve and the pair of tooth surfaces 31. Includes tooth tip 32. 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 from the axial center 2c side (inner peripheral side) of the face gear 2 toward the outer peripheral side. The inclined portion 35s is included.

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 set to the axial center 2c side (inner peripheral side) of the face gear 2. It increases from the surface toward the outer peripheral side of the face gear 2. Further, when the pinion tooth bottom surface 35 is viewed in a plan view, the pinion tooth bottom surface 35 narrows from the outer peripheral side of the face gear 2 toward the axial center 2c side (inner peripheral side) of the face gear 2.

Each outer pinion gear 4 includes a pinion shaft hole 4o through which the pinion shaft 5 is inserted (see FIG. 2), a plurality of pinion teeth 40 having tooth streaks extending parallel to the axis 4c (see FIG. 2), and a plurality of pinion teeth 40. It is a spur gear including a plurality of pinion tooth bottom surfaces 45 located between adjacent pinion teeth 40. In the present embodiment, each pinion tooth 40 is formed so as to extend in parallel with the axis 4c between a pair of tooth surfaces 41 formed by, for example, an involute curve and the pair of tooth surfaces 41. Includes tooth tip 42. 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 from the axial center 2c side (inner peripheral side) of the face gear 2 toward the outer peripheral side. The inclined portion 45s is included.

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 set to the axial center 2c side (inner peripheral side) of the face gear 2. It increases from the surface toward the outer peripheral side of the face gear 2. Further, when the pinion tooth bottom surface 45 is viewed in a plan view, the pinion tooth bottom surface 45 narrows from the outer peripheral side of the face gear 2 toward the axial center 2c side (inner peripheral side) of the face gear 2.

Further, as the inner pinion gear 3 and the outer pinion gear 4, those having the same number of teeth are adopted. In the present embodiment, the number of teeth of the inner pinion gear 3 and the number of teeth of the outer pinion gear 4 are both 9. 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 and obtains the face gear. The gear ratio Go of the two 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 (Go = 26/9 in this embodiment) is the gear ratio Gi between the plurality of inner gear teeth 21 and each inner pinion gear 3. In this embodiment, it is larger than Go = 20/9). The line segment L1 in FIG. 2 indicates a 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 is a line segment L2 with the plurality of outer gear teeth 25 of the face gear 2. The rolling pitch conical line with each outer pinion gear 4 is shown.

Further, 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 tooth tip circle diameter Dti of the inner pinion gear 3 is the tooth tip circle of the outer pinion gear 4. Same as diameter Dto. Further, in the present embodiment, the minimum value of the tooth bottom circle diameter of the inner pinion gear 3 is the same as the minimum value of the tooth bottom circle diameter of the outer pinion gear 4, and the maximum value of the tooth bottom circle diameter of the inner pinion gear 3 is the outer side. It is the same as the maximum value of the tooth bottom circle 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 paired with the plurality of inner gear teeth 21 of the face gear 2. The gear ratio with each of the inner pinion gears 3 is set to be larger than Gi. This makes it possible to prevent the pitch circle diameter Dpi of each inner pinion gear 3 from becoming smaller, and while suppressing an increase in the shaft length (thickness) of each face gear 2, each inner side as shown in FIG. A good wall thickness can be secured from the inner peripheral surface of the pinion gear 3 (inner peripheral surface of the pinion shaft hole 3o) to the pinion tooth bottom surface 35. As a result, it is possible to improve the strength, that is, the durability of each inner pinion gear 3 and thus the differential gear mechanism 1 as a whole while making the differential gear mechanism 1 compact.

Further, in the differential gear mechanism 1, the pitch circle diameter Dpi of each inner pinion gear 3 is the same as the pitch circle diameter Dpo of each outer pinion gear 4, and the tooth tip circle diameter Dti of each inner pinion gear 3 is each outer pinion gear. It is the same as the tooth tip circle diameter Dto of 4. As a result, while ensuring good 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 is satisfactorily suppressed. It becomes possible to do. 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 does not necessarily match. The tooth tip circle diameter Dti does not necessarily have to match the tooth tip circle diameter Dto of each outer pinion gear 4.

Further, in each face gear 2, the inner tooth tip surfaces 23 of the plurality of inner gear teeth 21 are inclined so as to approach the inner tooth bottom surface 24 from the axial center 2c side of the face gear 2 toward the outer peripheral side. Each of the outer tooth tip surfaces 27 of the plurality of outer gear teeth 25 including the portion 23s has an inclined portion 27s inclined so as to approach the outer tooth bottom surface 28 from the axial center 2c side of the face gear 2 toward the outer peripheral side. include. Further, each of the pinion tooth bottom surfaces 35 located between the adjacent pinion teeth 30 of the inner pinion gear 3 is inclined so as to approach the pinion tooth tip 32 from the axial center 2c side of the face gear 2 toward the outer peripheral side. Including part 35s. Further, each of the pinion tooth bottom surfaces 45 located between the adjacent pinion teeth 40 of the outer pinion gear 4 is inclined so as to approach the pinion tooth tip 42 from the axial center 2c side of the face gear 2 toward the outer peripheral side. Includes part 45s.

As a result, the wall thickness from the inner peripheral surface (inner peripheral surface of the pinion shaft holes 3o and 4o) of each inner pinion gear 3 and each outer pinion gear 4 to the pinion tooth bottom surfaces 35 and 45 is satisfactorily secured, and the inner pinion gear 3 and It is possible to improve the strength of the outer pinion gear 4 and thus the differential gear mechanism 1 as a whole. However, the inclined portions 23s, 27s from each inner tooth tip surface 23 and each outer tooth tip 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. 35s or 45s may be omitted. That is, the tooth tip circle diameter of each inner gear tooth 21 and each outer gear tooth 25 of each face gear 2 may be set to be constant, and the tooth bottom circle diameter of each pinion tooth bottom 35 of each inner pinion gear 3 and the tooth bottom circle diameter The diameter of the root circle of each pinion tooth bottom 45 of each outer pinion gear 4 may be fixed.

FIG. 3 is a perspective view showing another differential gear mechanism 1B of the present disclosure, and FIG. 4 is a partial cross-sectional view showing the differential gear mechanism 1B. Among the components of the differential gear mechanism 1B, the same elements as those of the differential gear mechanism 1 described above are designated by the same reference numerals, and redundant description will be omitted.

In each face gear 2B of the differential gear mechanism 1B shown in 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 defined to be the same. In the examples of FIGS. 3 and 4, the number of teeth of the inner gear tooth 21B and the number of teeth of the outer gear tooth 25B are 26. Further, in the differential gear mechanism 1B, as the outer pinion gear 4B, one having a number of teeth smaller than the number of teeth of the inner pinion gear 3B is adopted. In the examples 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 such a differential gear mechanism 1B, the gear ratio of each of the plurality of outer gear teeth 25B and the pair of outer pinion gears 4B is Go (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 (Gi = number of teeth of inner gear teeth 21B / number of teeth of inner pinion gear 3B = 26/12) of each of the plurality of inner gear teeth 21B and the pair of inner pinion gears 3B. This makes it possible to prevent the pitch circle diameter Dpi of each inner pinion gear 3B from becoming smaller, and while suppressing an increase in the shaft length (thickness) of each face gear 2B, as shown in FIG. 4, each inner side. A good wall thickness can be secured from the inner peripheral surface of the pinion gear 3B (inner peripheral surface of the pinion shaft hole 3o) to the pinion tooth bottom surface 35. As a result, it is possible to improve the strength, that is, the durability of each inner pinion gear 3B and thus the differential gear mechanism 1B as a whole while making the differential gear mechanism 1B compact. Further, in the differential gear mechanism 1B, the processing cost of the face gear 2 can be suppressed by making the number of teeth of the inner gear teeth 21B and the number of teeth of the outer gear teeth 25B the same.

Further, also 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 tooth tip circle diameter Dti of each inner pinion gear 3B is each outer side. It is the same as the 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 satisfactorily suppressed. It becomes possible to do. 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 does not necessarily match. The tooth tip circle diameter Dti does not necessarily have to match the tooth tip circle diameter Dto of each outer pinion gear 4B.

Further, also 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 from the axial center 2c side of the face gear 2B toward the outer peripheral side. The inclined portion 27s including the inclined portion 23s, each of the outer tooth tip surfaces 27 of the plurality of outer gear teeth 25B, is inclined so as to approach the outer tooth bottom surface 28 from the axial center 2c side of the face gear 2B toward the outer peripheral side. including. Further, each of the pinion tooth bottom surfaces 35 located between the adjacent pinion teeth 30 of the inner pinion gear 3B is inclined so as to approach the pinion tooth tip 32 from the axial center 2c side of the face gear 2B toward the outer peripheral side. Including part 35s. Further, each of the pinion tooth bottom surfaces 45 located between the adjacent pinion teeth 40 of the outer pinion gear 4B is inclined so as to approach the pinion tooth tip 42 from the axial center 2c side of the face gear 2 toward the outer peripheral side. Includes part 45s. Further, in the differential gear mechanism 1B, the minimum value of the tooth bottom circle diameter of the inner pinion gear 3B is the same as the minimum value of the tooth bottom circle diameter of the outer pinion gear 4B, and the maximum value of the tooth bottom circle diameter of the inner pinion gear 3B is. , It is the same as the maximum value of the tooth bottom circle diameter of the outer pinion gear 4B.

As a result, the wall thickness from the inner peripheral surface (inner peripheral surface of the pinion shaft holes 3o and 4o) of each inner pinion gear 3B and each outer pinion gear 4B to the pinion tooth bottom surfaces 35 and 45 is satisfactorily secured, and the inner pinion gear 3B and the inner pinion gear 3B and It is possible to improve the strength of the outer pinion gear 4B and thus the differential gear mechanism 1B as a whole. However, the inclined portions 23s, 27s, from each inner tooth tip surface 23 and each outer tooth tip 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, 35s or 45s may be omitted. That is, the tooth tip circle diameters of the inner gear teeth 21B and the outer gear teeth 25B of each face gear 2B may be set to be constant, and the tooth bottom circle diameter of each pinion tooth bottom surface 35 of each inner pinion gear 3B and the tooth bottom circle diameter of each pinion tooth bottom surface 35. The diameter of the root circle of each pinion tooth bottom 45 of each outer pinion gear 4B may be set to be constant.

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

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

In the differential gear mechanism of the present disclosure, the gear ratio of the plurality of outer gear teeth and each of the pair of outer pinion gears is set to be larger than the gear ratio of the plurality of inner gear teeth and each of the pair of inner pinion gears. This makes it possible to prevent the pitch circle diameter of each inner pinion gear from becoming smaller, and while suppressing an increase in the shaft length (thickness) of each face gear, from the inner peripheral surface of each inner pinion gear to the tooth bottom surface. A good wall thickness can be secured. As a result, it is possible to improve the strength, that is, the durability of the inner pinion gear and the entire differential gear mechanism while making the differential gear mechanism compact.

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 circle diameter (Dti) may be the same as the tooth tip circle diameter (Dto) of the outer pinion gears (4, 4B). As a result, it is possible to satisfactorily suppress an increase 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, each tooth tip surface (23) of the plurality of inner gear teeth (21, 21B) has a tooth bottom surface (24) toward the outer peripheral side from the axial center (2c) side of the face gear (2, 2B). An inclined portion (23s) inclined so as to approach is included, and each tooth tip surface (27) of the plurality of outer gear teeth (25, 25B) is an axial center of the face gear (2, 2B). An inclined portion (27s) inclined so as to approach the tooth bottom surface (28) from the side (2c) toward the outer peripheral side may be included, and between adjacent pinion teeth (30) of the inner pinion gears (3, 3B). Each of the pinion tooth bottom surfaces (35) located at is inclined so as to approach the pinion tooth tip (32) from the axial center (2c) side of the face gear (2, 2B) 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). An inclined portion (45s) inclined so as to approach the pinion tooth tip (42) from the axial center (2c) side toward the outer peripheral side may be included. As a result, it is possible to secure a good wall thickness from the inner peripheral surface of each inner pinion gear and each outer pinion gear to the tooth bottom surface, and improve the strength of the inner pinion gear and the outer pinion gear, and thus the entire differential gear mechanism.

Further, 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 tooth (25) is that of the inner gear tooth (21). It may be more than the number of teeth. As a result, the gear ratio between the plurality of outer gear teeth and each outer pinion gear can be made larger than the gear ratio between the plurality of inner gear teeth and each inner pinion gear while ensuring the strength of the inner pinion gear and the outer pinion gear. It will be possible.

Further, the number of teeth (3B) of the outer pinion gear may be smaller than the number of teeth of the inner pinion gear (4B), and the number of teeth of the outer gear tooth (25B) is the number of teeth of the inner gear tooth (21B). It may be the same as the number. As a result, the gear ratio between the plurality of outer gear teeth and each outer pinion gear can be made 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.

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

It goes without saying that the invention of the present disclosure is not limited to the above-described embodiment, and various changes can be made within the scope of the extension of the present disclosure. Furthermore, the above-described embodiment is merely a specific embodiment of the invention described in the column of the outline of the invention, and does not limit the elements of the invention described in the column of the outline of the invention.

The invention of the present disclosure can be used in the manufacturing field of a differential gear mechanism and the like.

1,1B differential gear mechanism, 2,2B face gear, 2c axis center, 2o shaft hole, 21,21B inner gear tooth, 22 tooth surface, 23 inner tooth tip surface, 23s inclined part, 24 inner tooth bottom surface, 25, 25B outer gear tooth, 26 tooth surface, 27 outer tooth tip surface, 27s inclined part, 28 outer tooth bottom surface, 3,3B inner pinion gear, 3c axis, 3o pinion shaft hole, 30 pinion tooth, 31 tooth surface, 32 pinion tooth Tip, 35 pinion tooth bottom, 35s inclined part, 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, 45s inclined part ..

Claims (6)

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

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