JP5194829B2 - Vehicle differential and its assembly method - Google Patents

Description

  The present invention relates to a vehicle differential device, and more particularly to a vehicle differential device including a pinion gear shaft for preventing a pinion gear that receives a rotational driving force from a drive side from falling down and an assembling method thereof.

  2. Description of the Related Art A differential for a vehicle includes a differential case that rotates in response to engine torque, a pair of side gears that are parallel to each other along the rotational axis of the differential case, and a pair of pinion gears that mesh with the side gears. (For example, Patent Document 1).

  The differential case is provided with an accommodating space for accommodating a pair of side gears and a pair of pinion gears. The differential case is provided with a pair of pinion gear insertion holes that communicate with the accommodation space and insert a pair of pinion gears, and a pair of axle insertion holes that open in a direction perpendicular to the axis of the pair of pinion gear insertion holes. It has been.

  The pair of side gears is composed of a bottomless cylindrical bevel gear having a boss portion and a gear portion, is arranged to be movable along the rotation axis of the differential case, and faces each boss portion into each axle insertion hole. It is rotatably supported in the differential case. In the pair of side gears, left and right axles are spline-fitted with a part of each being positioned in each axle insertion hole. An annular thrust washer positioned around each boss portion is interposed between the gear portion (back surface) of the pair of side gears and the inner peripheral edge of the pair of axle insertion holes.

  The pair of pinion gears is composed of a bottomless cylindrical bevel gear and is rotatably supported in each pinion gear insertion hole. A shaft insertion hole through which a pinion gear shaft for preventing gear collapse is inserted is provided in the shaft center portion of the pair of pinion gears.

  With the above configuration, when the torque from the engine side of the vehicle is input to the differential case via the drive pinion and the ring gear, the differential case is rotated about the rotation axis. Next, when the differential case is rotated, this rotational force is transmitted to the pair of pinion gears via the pinion gear shaft, and further transmitted from the pair of pinion gears to the pair of side gears. In this case, since the axle is connected to each side gear by spline fitting, the torque from the engine side is distributed according to the driving condition of the vehicle, and the drive pinion, ring gear, differential case, pinion gear shaft, and a pair of pinion gears And transmitted to the left and right axles via a pair of side gears.

  In this case, when the pair of pinion gears rotate, each slides on the respective support surfaces of the pinion gear insertion hole and the pinion gear shaft, so that friction resistance is generated between these support surfaces. The differential rotation of the side gear is limited.

In addition, a thrust force is generated on the meshing surfaces of the pair of side gears by the rotation of the pair of pinion gears, and the side gears move away from each other by the thrust force, and the back surfaces of the thrust washers are moved to the axle insertion holes. Since it is pressed against the periphery of the inner opening, a frictional resistance is generated between the back surface of each thrust washer and the inner opening periphery of each axle insertion hole, and the differential rotation of the pair of side gears is also limited by these frictional resistances.
Utility Model Registration No. 2520728 (FIG. 1)

  However, according to the vehicle differential of Patent Document 1, the sliding portion on the outer peripheral surface of the pinion gear is on the gear back side (the end surface side that is disposed at a position far from the rotational axis of the differential case on both end surfaces in the axial direction of the pinion gear). And a second sliding portion (gear portion top) corresponding to a part of the outer peripheral surface of the gear portion that is located on the rotation axis side of the differential case and is engaged with the side gear. Therefore, the contact area between the pinion gear insertion hole (inner peripheral surface of the pinion gear insertion hole) of the differential case and the second sliding portion varies depending on the rotation phase of the pinion gear, and a stable differential limiting torque is obtained. In addition, the gear size of the meshing part of the pinion gear cannot be set to a sufficiently large size, and the torque bias ratio (Torque Bias Ratio: TB) ) Has a problem that it is impossible to increase the degree of freedom in setting the.

  Accordingly, an object of the present invention is to provide a vehicle differential device and a method for assembling the same that can obtain a stable differential limiting torque and can increase the degree of freedom in setting a torque bias ratio. It is in.

(1) In order to achieve the above object, the present invention meshes a differential case, a pair of side gears rotatably accommodated in the differential case, and the pair of side gears with a gear shaft orthogonal to each other. A gear body provided with a shaft insertion hole in the center, a gear part provided on the outer peripheral side of the gear body, and a gear back part of the gear part that is provided over the entire periphery; And at least one pair of pinion gears having a gear flange portion formed integrally with the gear portion so as to protrude to the outside of the gear body portion, and a pinion gear shaft inserted through the shaft insertion hole and supported by the differential case, The differential case has at least one pair of pinion gear support portions that rotatably support the at least one pair of pinion gears by sliding on the outer peripheral surface of the gear collar portion, Pinion gears even pair, said one engagement portion of the side gears pair does not contain the supported portion relative to said differential case, said than gear collar portion is arranged to the rotational axis side of said differential case, the gear collar portion and the gear The gear base portion having a substantially T-shaped cross section consisting of the trunk portion has a thickness at the bent portion that is substantially the same as the maximum thickness of the gear flange portion, and the outer diameter of the gear flange portion is the tooth tip of the meshing portion. It is set to a size smaller than the circle diameter and larger than the root diameter of the meshing portion, the outer diameter of the gear flange portion is D, the tooth tip circle diameter of the gear portion is D1, and the gear back surface of the gear portion Provided is a vehicle differential device that satisfies the following inequality when the root diameter D2 of the side edge is satisfied .
D2 + (D1-D2) × 0.23 ≦ D ≦ D2 + (D1-D2) × 0.83

(2) In order to achieve the above object, the present invention meshes with a differential case, a pair of side gears rotatably accommodated in the differential case, and the pair of side gears with a gear shaft orthogonal to each other. A gear barrel having an axis as a gear axis, a gear portion provided on the outer periphery side of the gear barrel portion, and provided on an entire circumference of the gear back side of the gear portion, and integrated with the gear barrel portion and the gear portion. And at least one pair of pinion gears having a gear flange formed to protrude outward from the gear body, and the differential case rotates the at least one pair of pinion gears by sliding with an outer peripheral surface of the gear flange. And at least one pair of pinion gear support portions that are freely supported. The at least one pair of pinion gears has a meshing portion with the pair of side gears supported by the differential case. Part not include than said gear flange portion is disposed to the rotational axis side of said differential case, the gear collar portion and a substantially T-shaped cross section of the gear base portion consisting of the gear barrel portion, the thickness at the bent portion a maximum thickness substantially the same dimensions of the gear collar portion, the gear collar portion smaller outer diameter than the addendum circle diameter of the engagement portion of, and is set to a size larger than the dedendum circle diameter of the engagement portion, wherein When the outer diameter of the gear collar is D, the tooth tip diameter of the gear is D1, and the tooth root diameter D2 of the gear back side edge of the gear is to satisfy the following inequality: A vehicle differential device is provided.
D2 + (D1-D2) × 0.23 ≦ D ≦ D2 + (D1-D2) × 0.83

  According to the present invention, a stable differential limiting torque can be obtained, and the degree of freedom in setting the torque bias ratio can be increased.

[First embodiment]
FIG. 1 is a perspective view for explaining a vehicle differential device according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view for explaining the vehicle differential according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view showing a state in which the pinion gear and the pinion gear shaft are assembled to the differential case of the vehicle differential device according to the first embodiment of the present invention. FIGS. 4A and 4B are perspective views for explaining the pinion gear of the vehicle differential device according to the first embodiment of the present invention. FIG. 4A shows a state where the pinion gear is viewed obliquely from above, and FIG. 4B shows a state where the pinion gear is viewed obliquely from below. FIG. 5 is a cross-sectional view for explaining the pinion gear of the vehicle differential device according to the first embodiment of the present invention.

(Overall configuration of vehicle differential)
1 and 2, a vehicle differential device denoted by reference numeral 1 includes a differential case 2 that rotates upon receiving engine torque, a pinion gear shaft 50 that is positioned on an axis perpendicular to the rotational axis O of the differential case 2, The pair of pinion gears 3 and 4 parallel to each other on the pinion gear shaft 50 and a pair of side gears 5L and 5R meshing with the pair of pinion gears 3 and 4 with their gear axes orthogonal to each other are roughly configured.

(Configuration of differential case 2)
As shown in FIGS. 1 and 2, the differential case 2 has a space 2 </ b> A for accommodating the pinion gears 3, 4 and the side gears 5 </ b> L, 5 </ b> R, and is entirely formed of a one-piece member.

  As shown in FIGS. 1 and 2, the differential case 2 includes axle shaft insertion holes 9L and 9R that open along the rotation axis O, and a gear shaft having an axis in a direction perpendicular to the axis of the axle insertion holes 9L and 9R. Supporting portions 10, 11 and pin mounting holes 2b, 2b arranged in parallel at equal intervals (180 °) around the axis of one of the gear / shaft support portions 10, 11 are provided. . Further, as shown in FIG. 3, the differential case 2 is a symmetric region with respect to the rotational axis O and is spaced from the gear shaft support portions 10 and 11 at equal intervals in the circumferential direction (around the rotational axis O). Side gear passage holes 12L and 12R located in the part are provided. On the left axle side of the differential case 2, as shown in FIGS. 1 and 2, an annular ring gear mounting flange 13 is integrally provided along the circumferential direction in a plane orthogonal to the rotation axis O.

  As shown in FIG. 2, the axle shaft insertion holes 9 </ b> L and 9 </ b> R are formed by through holes that open in a direction along the rotation axis O. The left axle (not shown) is inserted through the axle insertion hole 9L, and the right axle (not shown) is inserted through the axle insertion hole 9R. Side gear receiving portions 9La and 9Ra made of spherical surfaces that slidably receive sliding portions (described later) of the side gears 5L and 5R are provided on the inner opening peripheral edges of the axle insertion holes 9L and 9R.

  As shown in FIG. 2, the gear / shaft support portions 10 and 11 are opened in the inside and outside of the differential case 2 with an axis perpendicular to the rotation axis O, and the inner diameter of the inner opening is larger than the inner diameter of the outer opening. These through holes (circular holes) are formed. The inner opening size of the gear / shaft support portions 10 and 11 is set to an inner diameter substantially equal to the outer diameter of the pinion gears 3 and 4 (an inner diameter smaller than the outer diameters of the side gears 5L and 5R).

  The inner surfaces of the inner opening portions of the gear / shaft support portions 10 and 11 are engaged with the pinion gears 3 and 4 and the side gears 5L and 5R in the axial direction of the pinion gear shaft 50 (torque from the pinion gears 3 and 4 to the side gears 5L and 5R). It is arranged at a position farther from the rotation axis O of the differential case 2 than the load center in the region where the tooth surfaces of both gears contact during transmission, and slides on the outer peripheral surfaces of the gear flanges 3B and 4B (described later) of the pinion gears 3 and 4 The first pinion gear support surfaces 10A and 11A are configured to rotatably support the pinion gears 3 and 4 by sliding that does not substantially change the area.

  As shown in FIG. 3, the inner surfaces of the outer openings of the gear / shaft support portions 10 and 11 are disposed farther from the rotation axis O of the differential case 2 than the first pinion gear support surfaces 10A and 11A. It is formed of pinion gear shaft support surfaces 10B and 11B that support both end portions so that they cannot rotate around the axis and cannot move in the axial direction.

  As shown in FIG. 2, pinion gear receiving portions (top portions) 10C and 11C formed of spherical surfaces having a predetermined curvature are provided on the stepped surfaces of the gear / shaft support portions 10 and 11, respectively.

  As shown in FIG. 2, the pin mounting holes 2 b and 2 b are opened along the rotation axis O on the inner peripheral surface of the first pinion gear support portion 10. The pin attachment holes 2b and 2b are fixed to both ends of a pin 52 that is inserted through the pin insertion hole 50D of the pinion gear shaft 50. Thereby, the pinion gear shaft 50 is supported by the differential case 2 via the pin 52. For this reason, the pinion gear shaft 50 is prevented from rotating around its axis and is prevented from coming off in the axial direction.

  As shown in FIGS. 1 and 3, the side gear passage holes 12 </ b> L and 12 </ b> R are formed by through holes having planar non-circular openings. The opening size is set such that the pinion gears 3 and 4 and the side gears 5L and 5R can be inserted into the differential case 2.

(Configuration of pinion gear shaft 50)
As shown in FIG. 2, the pinion gear shaft 50 has second pinion gear support surfaces 50A and 50B that rotatably support the pinion gears 3 and 4 by sliding with inner surfaces of shaft insertion holes 3D and 4D (described later) of the pinion gears 3 and 4. And are supported by the pinion gear shaft support surfaces 10B and 11B of the differential case 2 (gear and shaft support portions 10 and 11) through the pinion gears 3 and 4 (shaft insertion holes 3D and 4D). The pinion gear shaft 50 is fixed so that there is substantially no gap between the outer peripheral surface thereof and the pinion gear shaft support surfaces 10 </ b> B and 11 </ b> B so as not to move relative to the differential case 2.

  The second pinion gear support surfaces 50A, 50B are parallel to the first pinion gear support surfaces 10A, 11A along the axial direction of the pinion gear shaft 50, and are spaced apart from the gear / shaft support portions 10, 11 at a predetermined interval. Is arranged. At least a part of the second pinion gear support surfaces 50A, 51B is disposed at a position closer to the rotational axis O of the differential case 2 than the center point of engagement between the pinion gears 3, 4 and the side gears 5L, 5R in the axial direction of the pinion gear shaft 50. Yes.

(Configuration of pinion gears 3 and 4)
Since the pinion gears 3 and 4 have substantially the same configuration, only the pinion gear 3 will be described, for example. In addition, about the pinion gear 4, the code | symbol of each site | part is attached | subjected corresponding to the code | symbol of each site | part of the pinion gear 3 (For example, 4A corresponding to the gear body part 3A of the pinion gear 3 is attached to the gear body part of the pinion gear 4, Further, 4B is attached to the gear flange portion of the pinion gear 4 corresponding to the gear flange portion 3B of the pinion gear 3), and the description thereof is omitted.

  As shown in FIGS. 4 (a), 4 (b), and 5, the pinion gear 3 is a gear barrel 3A having a central axis as a gear axis C, and a first supported portion protruding outside the gear barrel 3A. 2B and a gear portion 3C (meshing portion with the side gears 5L and 5R) located on the side gear side of the gear barrel portion 3A and the gear flange portion 3B. As shown in FIG. 1, the first pinion gear support surface 10A of the gear / shaft support surface 10 and the second pinion gear support surface 50A of the pinion gear shaft 50 are rotatably supported. As the pinion gear 3, a gear having 3 gear teeth, for example (the normal number of teeth of the pinion gear in the conventional vehicle differential device is 9 or 10) is used.

  As shown in FIG. 2, the gear body portion 3 </ b> A has a shaft insertion hole 3 </ b> D through which the pinion gear shaft 50 is inserted in an axial center portion (a portion including the central axis), and the entire first gear body portion is substantially annular. 30a and the substantially cylindrical body which consists of the substantially gear-shaped second gear trunk | drum 31a. The gear body 3A and the gear flange 3B are connected to each other by a gentle concave curved surface on the side gear side.

  As shown in FIG. 5, the shaft insertion hole 3 </ b> D is formed by stepped holes having three large, medium, and small inner surfaces with different inner diameters. The inner surface having the smallest inner diameter among the inner surfaces of the shaft insertion hole 3D is disposed closer to the rotation axis O of the differential case 2 than the other inner surfaces, and slides on the second pinion gear support surface 50A of the pinion gear shaft 50. It is formed by a second sliding surface 30A as a support portion.

  Of the inner surfaces of the shaft insertion hole 3D, the inner surface having the largest inner diameter is disposed farther from the rotation axis O of the differential case 2 than the second sliding surface 30A, and does not slide on the outer peripheral surface of the pinion gear shaft 50. It is formed by the surface 31A.

  Among the inner surfaces of the shaft insertion hole 3D, the inner surface of the intermediate diameter (the diameter between the maximum diameter and the minimum diameter) is disposed between the second sliding surface 30A and the non-sliding surface 31A, and the outer periphery of the pinion gear shaft 50 The non-sliding surface 32A that does not slide on the surface is formed. The gear back side opening of the shaft insertion hole 3D is formed by an opening that gradually widens from the gear axial direction intermediate portion toward the gear back side.

  Here, the “gear back surface” refers to an end surface disposed at a position far from the rotation axis O of the differential case 2 among both end surfaces in the gear axial direction of the pinion gear 3.

  The first gear body 30a is on the gear back side of the gear body 3A, and the second gear body 31a is on the gear front surface side of the gear body 3A (opposite of the gear back side in the axial direction of the gear body 3A). Side). The gear flange 3B is disposed on the outer peripheral surface of the first gear body 30a, and the tooth base of the gear portion 3C is disposed on the outer peripheral surface of the second gear body 31a.

  As shown in FIG. 2, the gear flange portion 3B is integrally provided on the outer peripheral surface of the first gear body portion 30a over the entire circumference, and the whole has a uniform outer diameter along the gear axial direction. Is formed by. And it is comprised so that it may function as a gear base part (site | part except the gear part 3C in the pinion gear 3) in the pinion gear 3 with the gear trunk | drum 3A.

  As shown in FIG. 5, the bent portion A of the gear base portion has a thickness t1 set to be approximately the same dimension (t1≈t2) as the maximum thickness t2 of the gear flange portion 3B. This can contribute to uniform rigidity at the gear base end.

  As shown in FIGS. 2 and 5, the outer peripheral surface of the gear flange 3 </ b> B is a first sliding surface 30 </ b> B as a first supported portion that slides on the first pinion gear support surface 10 </ b> A of the gear / shaft support surface 10. Is formed.

  As shown in FIGS. 2 and 5, the rear surface of the gear flange 3B is adapted to the pinion gear receiving portion 10C of the gear / shaft support portion 10 and is a third supported portion that slides on the pinion gear receiving portion 10C. 3 sliding surfaces 31B are formed.

  2 and 5, the gear portion 3C does not include a sliding portion as a supported portion with respect to the differential case 2, and is disposed at a position closer to the rotation axis O of the differential case 2 than the gear flange portion 3B. .

  A part of the gear back side edge of the gear portion 3C is integrally provided on the gear tip side end surface of the gear flange portion 3B. That is, the tip circle diameter D1 of the gear portion 3C is set to be larger than the outer diameter D (D1> D) of the gear flange portion 3B. As a result, the tooth surface size of the gear portion 3C can be set to a large dimension, and the meshing area between the gear portion 3C and the side gears 5L, 5R can be widened, and the degree of freedom in setting the torque bias ratio is increased. Can do. Further, since the gear flange 3B functions as a reinforcing member for the gear 3C, the stress acting on the pinion gear 3 due to the load from the side gears 5L and 5R is dispersed, and the number of teeth of the gear 3C is reduced to reduce the gear 3C. The bending strength (tooth surface strength) of each gear tooth can be increased. Thereby, the fluctuation | variation of the meshing position of the pinion gear 3 and side gear 5L, 5R can be reduced, and the stable differential limiting torque can be obtained. Furthermore, reducing the number of teeth of the gear portion 3C and increasing the bending strength eliminates the need to set the size of the entire pinion gear to a large size and can prevent the differential case 2 from becoming large.

  Here, the (1) stress dispersion effect and (2) the tooth number reduction effect of the pinion gear 3 in the vehicle differential device 1 shown in the present embodiment will be considered with reference to FIGS. 2, 6, and 7.

(1) Consideration about the stress dispersion effect This consideration is based on a vehicle differential device using ten types of gears having different outer diameters (flange diameters) D of the gear flanges 3B and 4B as the pinion gears 3 and 4, respectively. After driving for a predetermined time, an attempt was made by measuring the tooth surface strength from the stress of the contact surfaces of the various gears with the side gears 5L and 5R.

  As a result, as shown in FIG. 2, the outer diameter (flange diameter) D (variable) of the gear flanges 3B and 4B in the pinion gears 3 and 4 is a percentage, for example, the tip diameter D1 (constant) of the gear portions 3C and 4C. The flange diameter D of the gear flange portions 3B and 4B having the same dimensions as D is represented by D = D1 = 100%, and the gear flange having the same dimension as the tooth root circle diameter D2 (constant) of the gear rear side edge. When the flange diameter D of the parts 3B and 4B is expressed as D = D2 = 0%, the tooth surface strength of the gear having the flange diameter D = 23% to 83% exceeds the desired tooth surface strength and has a stress dispersion effect. Was confirmed. Here, the flange diameter D = 23% means that D = D2 + (D1-D2) × 0.23.

  On the other hand, a gear having a flange diameter D of 0 ≦ D <23% has a low overall rigidity, and a desired tooth surface strength cannot be obtained. In addition, since the gear having a flange diameter D of 83% <D ≦ 100% partially increases in rigidity, stress concentration occurs in a portion having a low rigidity, and the gear having a flange diameter D of 0 ≦ D <23%. Like the above, the desired tooth surface strength cannot be obtained.

  This is as shown in FIG. FIG. 6 is a graph showing the result of considering the stress dispersion effect of the pinion gear in the vehicle differential device according to the first embodiment of the present invention. In FIG. 6, the vertical axis represents the tooth surface strength, and the horizontal axis represents the flange diameter (%).

(2) Consideration about the effect of reducing the number of teeth In the present embodiment, the number of teeth of the pinion gears 3 and 4 is set to 7 less than the normal number of teeth (9 or 10). The pinion gears 3 and 4 are not only supported by the second pinion gear support surfaces 50A and 50B of the pinion gear shaft 50 by the second sliding surfaces 30A and 40A, but are also the first outer surfaces of the gear flanges 3B and 4B. The sliding surfaces 30B and 40B are supported by the first pinion gear support surfaces 10A and 11A of the gear and shaft support portions 10 and 11, respectively. Therefore, the pinion gear shaft 50 can be made thinner than the pinion gear shaft of the conventional vehicle differential, and the number of teeth of the pinion gears 3 and 4 can be reduced.

  In this discussion, after driving a vehicle differential device using six types of gears having different numbers of teeth N (N = 5 to 10) as the pinion gears 3 and 4 over a predetermined time, the side gears 5L of the various gears are driven. , 5R was attempted by measuring the tooth surface strength from the stress of the contact surface against 5R.

  As a result, it was confirmed that the tooth surface strength of the gear having N number of teeth of N = 6 to 8 exceeds the desired tooth surface strength and has the effect of reducing the number of teeth.

  On the other hand, a gear having N = 5 teeth cannot obtain a desired tooth surface strength. This is considered to be due to the fact that the tooth surface becomes deeply bent and the tooth surface strength cannot be increased. In addition, the gear having N = 9, 10 teeth has a small tooth surface size and a desired tooth surface strength cannot be obtained.

  This is as shown in FIG. FIG. 7 is a graph showing the results of considering the effect of reducing the number of teeth of the pinion gear in the vehicle differential device according to the first embodiment of the present invention. In FIG. 7, the vertical axis indicates the tooth surface strength, and the horizontal axis indicates the number of teeth.

  In addition, although the pinion gear with the number N of teeth of N = 2 to 4 can theoretically be manufactured and processed, it is practically difficult to ensure a good meshing rate.

(Configuration of side gears 5L, 5R)
As shown in FIGS. 1 and 2, the side gears 5L and 5R are substantially annular gears having outer boss portions 5La and 5Ra and gear portions 5Lb and 5Rb having different outer diameters (the outer diameter larger than the outer diameter of the pinion gears 3 and 4). The bevel gear has a diameter and has a single tip cone angle, is rotatably supported in the differential case 2 (space portion 2A), and is configured to mesh with the pinion gears 3 and 4. The number of teeth of the side gears 5L and 5R is set to 1.7 or more times the number of teeth of the pinion gears 3 and 4 (for example, the number of teeth of the side gears 5L and 5R is 12 with respect to the number of teeth 7 of the pinion gears 3 and 4). Yes.

  Sliding portions 5Lc and 5Rc made of spherical surfaces that fit the side gear receiving portions 9La and 9Ra are provided on the rear surfaces of the side gears 5L and 5R. The spherical centers of the sliding portions 5Lc and 5Rc are arranged on the rotation axis O of the differential case 2. In the side gears 5L and 5R, left and right axles (not shown) are respectively inserted into the axle insertion holes 9L and 9R and are spline-fitted.

[Operation of the differential 1 for a vehicle]
When torque from the engine side of the vehicle is input to the differential case 2 via the drive pinion and the ring gear, the differential case 2 rotates about the rotation axis O. When the differential case 2 rotates, this rotational force is transmitted to the pinion gears 3 and 4 via the pinion gear shaft 50 and further transmitted from the pinion gears 3 and 4 to the side gears 5L and 5R. In this case, since the axles (not shown) are spline-fitted to the left and right side gears 5L and 5R, the torque from the engine side is driven by the drive pinion, ring gear, differential case 2, pinion gear shaft 50, pinion gears 3, 4,. It is transmitted to the left and right axles via the side gears 5L and 5R.

  Here, when the vehicle is in a straight traveling state and no slip occurs between the left and right wheels and the road surface, when torque from the engine side is transmitted to the differential case 2, the pinion gears 3 and 4 are connected to the side gears 5L and 5R. Since the pinion gears 3 and 4 and the side gears 5L and 5R rotate together with the differential case 2 and the pinion gear shaft 50, the torque from the engine side is equally transmitted to the left and right axles. The left and right wheels rotate at the same rotational speed.

  On the other hand, for example, when the right wheel falls into a muddy state and slip occurs between the road surface, the pinion gears 3 and 4 rotate while meshing with the side gears 5L and 5R, so that the torque from the engine side is applied to the left and right axles. Differentially distributed among the (wheels), the left wheel rotates at a speed lower than the rotational speed of the differential case 2, and the right wheel rotates at a speed higher than the rotational speed of the differential case 2.

  In the present embodiment, when the pinion gears 3 and 4 rotate while torque is applied to the differential case 2, the first sliding surfaces 30B and 40B slide on the first pinion gear support surfaces 10A and 11A, and the second sliding surface. Since the surfaces 30A, 40A slide on the second pinion gear support surfaces 50A, 50B of the pinion gear shaft 50, between the first slide surfaces 30B, 40B and the first pinion gear support surfaces 10A, 11A and the second slide surface 30A. , 40A and the second pinion gear support surfaces 50A, 50B generate a frictional resistance. These frictional resistances limit the differential rotation of the side gears 5L and 5R, and the slip generated between the left and right wheels and the road surface is suppressed.

  In the present embodiment, the rotation of the pinion gears 3 and 4 generates a thrust force in the direction of the rotation axis of each gear on the meshing surfaces with the side gears 5L and 5R. This thrust force causes the side gears 5L, 5R to move away from each other and press the thrust washers 6L, 6R against the thrust washer receiving portions 9La, 9Ra. Therefore, the thrust washers 6L, 6R Friction resistance is generated between them, and the differential rotation of the side gears 5L and 5R is also limited by these frictional resistances. Further, since the third sliding surfaces 31B and 41B of the pinion gears 3 and 4 are in pressure contact with the pinion gear receiving portions 10C and 11C of the differential case 2 by the thrust force generated in the pinion gears 3 and 4, the friction resistance against the rotation of the pinion gears 3 and 4 is increased. This also limits the differential rotation of the side gears 5L and 5R.

  Next, a method for assembling the vehicle differential device according to the present embodiment will be described with reference to FIGS. 2, 8, 9 (a) and 9 (b). FIG. 8 is a flowchart for explaining the method of assembling the vehicle differential device according to the first embodiment of the present invention. FIGS. 9 (a) and 9 (b) are perspective views for explaining a method of assembling the vehicle differential device (incorporation of side gear) according to the first embodiment of the present invention. FIG. 9A shows the side gear at the side gear insertion position in the differential case, and FIG. 9B shows the side gear at the side gear intermediate position in the differential case (position between the side gear insertion position and the side gear built-in position).

  In the method of assembling the vehicle differential shown in the present embodiment, the steps of “incorporation of pinion gear and pinion gear shaft”, “meshing of pinion gear and side gear”, and “incorporation of side gear” are sequentially performed. Each of these steps will be described sequentially.

"Incorporation of pinion gear and pinion gear shaft"
First, the pinion gear 3 is inserted into the differential case 2 (space portion 2A) from the side gear passage holes 12L and 12R, and the pinion gear shaft 50 is sequentially inserted into the gear / shaft support portion 10 of the differential case 2 and the shaft insertion hole 3D of the pinion gear 3.

  Next, the pinion gear 4 is inserted into the differential case 2 through the side gear passage holes 12L and 12R, and the pinion gear shaft 50 inserted into the gear / shaft support 10 of the differential case 2 and the shaft insertion hole 3D of the pinion gear 3 is inserted into the shaft insertion hole of the pinion gear 4. 4D and the gear / shaft support 11 of the differential case 2 are sequentially inserted, and then both ends of the pinion gear shaft 50 at positions where the pin insertion holes 50D of the pinion gear shaft 50 are arranged on the axis of the pin mounting holes 2b, 2b of the differential case 2. The portions are supported on the pinion gear shaft support surfaces 10B and 11B of the gear and shaft support portions 10 and 11, respectively.

  In this case, the pinion gear 4 may be inserted into the differential case 2 before the pinion gear shaft 50 is inserted through the gear / shaft support 10 of the differential case 2 and the shaft insertion hole 3D of the pinion gear 3.

  Thereafter, the pin 52 is inserted into one of the pin mounting holes 2b, 2b of the differential case 2 and further inserted into the pin insertion hole 50D of the pinion gear shaft 50, and then the pin mounting holes 2b, The pinion gear shaft 50 is fixed to the differential case 2 by being inserted into the other pin mounting hole 2b of 2b (the pinion gear shaft 50 is positioned in the axial direction and around the axis).

  In this case, when the pinion gear shaft 50 is fixed to the differential case 2, the pinion gears 3 and 4 are inserted into the pinion gear shaft 50 so as to be able to rotate and advance and retract while being inserted through the shaft insertion holes 3D and 4D of the pinion gears 3 and 4. In this state, each is incorporated into the differential case 2 (step S1 in FIG. 8).

"Meshing of pinion gear and side gear"
The first sliding surfaces 30B and 40B of the gear flanges 3B and 4B are connected to the first pinion gear support surfaces 10A and 11A of the gear shaft support portions 10 and 11, and the gear body portions 3A and 4A (shaft insertion holes 3D and 4D). The second sliding surfaces 30A and 40A face the second pinion gear support surfaces 50A and 50B of the pinion gear shaft 50, respectively, and the pinion gears at positions where the gear portions 3C and 4C are exposed in the opening surfaces of the side gear passage holes 12L and 12R. 3 and 4 are held by the pinion gear shaft 50, and the side gears 5L and 5R are inserted into the differential case 2 from the side gear passage holes 12L and 12R along the direction in which the gear axis is orthogonal to the gear axis of the pinion gears 3 and 4. 5Lb and 5Rb are engaged with the gear portions 3C and 4C of the pinion gears 3 and 4 (step S2 in FIG. 8).

  In this case, when the gear portions 5Lb and 5Rb of the side gears 5L and 5R are engaged with the gear portions 3C and 4C of the pinion gears 3 and 4, the spherical centers of the sliding portions 5Lc and 5Rc of the side gears 5L and 5R are the rotation axis of the differential case 2. Placed on O.

"Incorporation of side gear"
While maintaining the state where the gear portions 5Lb and 5Rb of the side gears 5L and 5R are engaged with the gear portions 3C and 4C of the pinion gears 3 and 4, the side gears 5L and 5R are moved along the axis of the pinion gear shaft 50 (pinion gears 3 and 4). By rotating in the same direction (clockwise or counterclockwise), the side gear insertion position shown in FIG. 9A to the intermediate position shown in FIG. 9B (between the side gear insertion position and the side gear installation position). Position) is arranged at the side gear assembly position (position shown in FIG. 1) on the rotation axis O of the differential case 2.

  In this case, the rotation of the side gears 5L and 5R in the vicinity of the side gear assembly position causes the back surface (sliding portions 5Lc and 5Rc) to slide on the inner peripheral edges (side gear receiving portions 9La and 9Ra) of the axle insertion holes 9L and 9R. By doing. When the side gears 5L and 5R are arranged at the side gear assembly position, the side gears 5L and 5R are assembled in the differential case 2 with their sliding portions 5Lc and 5Rc facing the side gear receiving portions 9La and 9Ra of the axle insertion holes 9L and 9R ( Step S3 in FIG.

[Effect of the first embodiment]
According to the first embodiment described above, the following effects can be obtained.

(1) The first sliding surfaces 30B and 40B of the pinion gears 3 and 4 are the first pinion gear support surfaces 10A and 11A of the differential case 2, and the second sliding surfaces 30A and 40A are the second pinion gear support surfaces 50A of the pinion gear shaft 50. , 50B, so that the inclination of the pinion gears 3 and 4 can be reliably suppressed, so that seizure and uneven wear of the pinion gears 3 and 4 or the support surface thereof (particularly the edge portion of the pinion gear) are suppressed. In addition, it is possible to obtain a good meshing state between the pinion gears 3 and 4 and the side gears 5L and 5R.

(2) Since the first pinion gear support surfaces 30B and 40B of the differential case 2 support only the gear flanges 3B and 4B, the tooth tip diameter D1 of the gear portions 3C and 4C is equal to that of the gear flanges 3B and 4B. Since the dimension is set larger than the outer diameter D (D1> D), the tooth surface size of the gear parts 3C, 4C is set to a large dimension so that the meshing area between the gear parts 3C, 4C and the side gears 5L, 5R is set. The degree of freedom in setting the torque bias ratio can be increased.

(3) Since the gear flange portions 3B and 4B function as reinforcing members for the gear portions 3C and 4C, the stress acting on the pinion gears 3 and 4 due to the load from the side gears 5L and 5R is dispersed and the gear portions 3C and 4C The number of teeth can be reduced to increase the bending strength of the gear portions 3C and 4C. Thereby, the fluctuation | variation of the meshing position of the pinion gear 3 and side gear 5L, 5R can be reduced, and the stable differential limiting torque can be obtained.

(4) The reduction in the number of teeth of the gear portions 3C and 4C to 8 or less and the increase in the bending strength eliminates the need to set the entire pinion gear to a large size, and the large size of the differential case 2 Can be prevented.

(5) Since a thrust washer is not interposed between the rear surfaces (sliding portions 5Lc, 5Rc) of the side gears 5L, 5R and the inner opening rims of the axle insertion holes 9L, 9R, the number of apparatus assembly steps can be reduced. As a result, the assembling work can be simplified. Further, the dimensional accuracy of the side gears 5L, 5R can be relaxed, and the cost can be reduced.

  In the method for assembling the vehicle differential shown in the present embodiment, in the “meshing pinion gear and side gear” step, the side gears 5L and 5R have their gear axes orthogonal to the gear axis of the pinion gears 3 and 4. Although the case where the gear portions 5Lb and 5Rb are engaged with the gear portions 3C and 4C of the pinion gears 3 and 4 by inserting them into the differential case 2 from the side gear passage holes 12L and 12R along the direction has been described, the present invention is not limited thereto. First, the side gears 5L and 5R are inserted into the differential case 2 through the side gear passage holes 12L and 12R along the direction in which the pinion gears 3 and 4 rotate, and the gear portions 5Lb and 5Rb are engaged with the gear portions 3C and 4C of the pinion gears 3 and 4, respectively. You may combine them.

  In the step of “incorporating the side gear”, the side gears 5L and 5R are rotated in the same direction along the axis of the pinion gear shaft 50, so that the side gear insertion position shown in FIG. And a side gear intermediate position (1) shown in FIG. 10 and a side gear intermediate position (2) shown in FIG. 10 (c).

  FIGS. 10A to 10D are cross-sectional views for explaining another “incorporating side gear” step in the method for assembling the vehicle differential device according to the first embodiment of the present invention. . 10A shows the side gear insertion position, FIGS. 10B and 10C show the side gear intermediate position, and FIG. 10D shows the state where the side gear is arranged at the side gear assembly position. Here, the number of teeth of the side gears 5L and 5R is not limited to the above-described twelve, but the number of teeth is desirably an even number rather than an odd number. This is because, when the side gears 5L and 5R are inserted from the side gear passage holes 12L and 12R as shown in FIG. 10A, when the side gears 5L and 5R have an odd number of teeth, they can be easily inserted while meshing with the pinion gear 3. If the phases of the side gears 5L and 5R are determined, the pinion gear 4 will not mesh with the pinion gear 4 at an appropriate position. However, if the side gears 5L and 5R have an even number of teeth, the pinion gears 3 and 4 are inserted while meshing at a good position. It is because it can do. Therefore, if the number of teeth of the side gears 5L and 5R is an even number, assembly is possible even if the side gear passage holes 12L and 12R are made smaller than in the case of an odd number, and the rigidity of the differential case 2 can be increased.

[Second Embodiment]
FIG. 11 is a cross-sectional view for explaining a vehicle differential device according to a second embodiment of the present invention. In FIG. 11, members that are the same as or equivalent to those in FIGS. 1 to 5 are given the same reference numerals, and detailed descriptions thereof are omitted.

  As shown in FIG. 11, the vehicle differential device 100 according to the second exemplary embodiment includes the rear surfaces of the side gears 5L and 5R (sliding portions 5Lc and 5Rc made of spherical surfaces) and the inner openings of the axle insertion holes 9L and 9R. It is characterized in that spherical thrust washers 6L and 6R adapted to the sliding portions 5Lc and 5Rc are interposed between the peripheral edges.

  Therefore, thrust washer receiving portions 9Lb and 9Rb adapted to the spherical thrust washers 6L and 6R are provided on the inner opening periphery of the axle insertion holes 9L and 9R in the differential case 2 instead of the side gear receiving portions 9La and 9Ra.

  Next, a method for assembling the vehicle differential device according to the present embodiment will be described with reference to FIG. FIG. 12 is a flowchart for explaining an assembling method of the vehicle differential according to the second embodiment of the present invention.

  The method of assembling the vehicle differential shown in the present embodiment includes "incorporation of pinion gear and pinion gear shaft", "incorporation of side gear", "meshing of pinion gear and side gear", and "incorporation of spherical thrust washer". Since the steps are performed sequentially, each of these steps will be described in turn.

  The process of “incorporating pinion gear and pinion gear shaft” (step S1 in FIG. 12) shown in the present embodiment is performed in the same manner as the process of “incorporating pinion gear and pinion gear shaft” shown in the first embodiment. Therefore, the description is omitted.

"Incorporation of side gear"
The first sliding surfaces 30B and 40B of the gear flanges 3B and 4B are connected to the first pinion gear support surfaces 10A and 11A of the gear shaft support portions 10 and 11, and the gear body portions 3A and 4A (shaft insertion holes 3D and 4D). The second sliding surfaces 30A and 40A face the second pinion gear support surfaces 50A and 50B of the pinion gear shaft 50, respectively, and the pinion gears at positions where the gear portions 3C and 4C are exposed in the opening surfaces of the side gear passage holes 12L and 12R. 3 and 4 are held by the pinion gear shaft 50, and the side gears 5L and 5R are inserted into the differential case 2 from the side gear passage holes 12L and 12R along the direction in which the gear axis is orthogonal to the gear axis of the pinion gears 3 and 4, The side gears 5L and 5R are rotated in the same direction (clockwise or counterclockwise) along the 50 axis. By Rukoto, placed on the rotation axis O of the differential case 2.

  In this case, when the side gears 5L and 5R are arranged on the rotation axis O, the side gears 5L and 5R are incorporated in the differential case 2 with their sliding portions 5Lc and 5Rc facing the thrust washer receiving portions 9Lb and 9Rb of the axle insertion holes 9L and 9R. (Step S2 in FIG. 12).

"Meshing of pinion gear and side gear"
The side gears 5L and 5R are moved along the rotation axis O in a direction approaching each other and meshed with the gear portions 5Lb and 5Rb and the gear portions 3C and 4C of the pinion gears 3 and 4 (step S3 in FIG. 12).

  In this case, when the gear portions 5Lb, 5Rb of the side gears 5L, 5R are engaged with the gear portions 3C, 4C of the pinion gears 3, 4, the sliding portions 5Lc, 5Rc of the side gears 5L, 5R and the thrust washer receiving portion 9Lb of the differential case 2 , 9Rb, a gap is formed along the rotation axis O.

"Incorporation of spherical thrust washer"
Spherical thrust washers 6L, 6R are inserted into the differential case 2 from the side gear passage holes 12L, 12R, and the spherical thrust washers are inserted between the sliding portions 5Lc, 5Rc of the side gears 5L, 5R and the thrust washer receiving portions 9Lb, 9Rb of the differential case 2. 6L and 6R are installed. Spherical thrust washers 6L and 6R have gap sizes formed between the sliding portions 5Lc and 5Rc of the side gears 5L and 5R and the thrust washer receiving portions 9Lb and 9Rb of the differential case 2 in "meshing of the pinion gear and the side gear". A spherical thrust washer with a thickness or number corresponding to the above is used.

  In this case, when the spherical thrust washers 6L and 6R are interposed between the side gears 5L and 5R and the thrust washer receiving portions 9Lb and 9Rb, the spherical thrust washers 6L and 6R are incorporated into the differential case 2 (step of FIG. 12). S4).

[Effect of the second embodiment]
According to the second embodiment described above, the following effects can be obtained in addition to the effects (1) to (4) of the first embodiment.

  Between the sliding portions 5Lc, 5Rc of the side gears 5L, 5R and the thrust washer receiving portions 9Lb, 9Rb of the differential case 2, spherical thrust washers 6L, 6R having a thickness corresponding to the gap dimension can be interposed. The assembly error in the rotation axis direction in the differential case 2 can be absorbed.

  As mentioned above, although the vehicle differential gear of this invention was demonstrated based on said embodiment, this invention is not limited to said embodiment, In various aspects in the range which does not deviate from the summary. For example, the following modifications are possible.

(1) In each of the embodiments, the case has been described in which the gear flange portions 3B and 4B are formed of an annular body having a uniform outer diameter along the gear axial direction. However, the present invention is limited to this. Alternatively, the gear collar may be formed of an annular body having a size (for example, the outer peripheral surface is an inclined surface) having a different outer diameter along the gear axial direction. That is, in short, the gear collar portion of the pinion gear according to the present invention may be formed of an annular body having a uniform dimension in the gear axial direction along the circumferential direction. In this case, the differential case is provided with a support surface (first pinion gear support surface) adapted to the outer peripheral surface (first sliding surface) of the gear flange.

(2) In each embodiment, the case where the gear portions 3C and 4C have seven teeth has been described. However, the present invention is not limited to this and is a gear portion having six or eight teeth. However, the same effect as this embodiment can be obtained.

(3) In each embodiment, although the case where the two pinion gears 3 and 4 are arrange | positioned in the differential case 2 was demonstrated, this invention is not limited to this, Three or more pinion gears are made into a differential case. You may arrange in.

(4) In each embodiment, the inner diameter of the shaft insertion holes 3D and 4D of the pinion gears 3 and 4 is smaller in the second sliding surfaces 30A and 40A than the non-sliding surfaces 32A and 42A (shaft insertion holes 3D and 4D The case where the inner diameter of the second sliding surfaces 30A and 40A is set to the smallest dimension has been described, but the present invention is not limited to this, and the second sliding surface is formed on the inner surfaces of the shaft insertion holes 3D and 4D. If only 30A and 40A are configured to slide on the second pinion gear support surfaces 50A and 50B of the pinion gear shaft 50, for example, the inner diameters of the shaft insertion holes 3D and 4D of the pinion gears 3 and 4 are set to the second sliding surfaces 30A and 40A and The non-sliding surfaces 32A and 42A may be set to the same size. In this case, the pinion gear shaft 50 is formed by setting the outer diameter of the part facing the second sliding surfaces 30A, 40A to a dimension larger than the outer diameter of the other part.

(5) In each embodiment, although the case where the differential case 2 was formed by one piece of member was demonstrated, this invention is not limited to this, Of course, the differential case which consists of a some case element may be sufficient.

(6) In each embodiment, although the case where it was the vehicle differential device 1 provided with the pinion gear shaft 50 was demonstrated, this invention is not limited to this, The drive of the vehicle differential device as a support structure of a pinion gear A shaftless type vehicle differential without a pinion gear shaft may be used as long as it is possible to provide a support structure in which the pinion gear does not tilt sometimes.

The perspective view shown in order to demonstrate the differential for vehicles which concerns on the 1st Embodiment of this invention. Sectional drawing shown in order to demonstrate the differential for vehicles which concerns on the 1st Embodiment of this invention. Sectional drawing which shows the assembly | attachment state of the pinion gear and pinion gear shaft with respect to the differential case of the differential for vehicles which concerns on the 1st Embodiment of this invention. (A) And (b) is a perspective view shown in order to demonstrate the pinion gear of the differential for vehicles which concerns on the 1st Embodiment of this invention. Sectional drawing shown in order to demonstrate the pinion gear of the differential for vehicles which concerns on the 1st Embodiment of this invention. The graph which shows the result of having considered the stress dispersion | distribution effect of the pinion gear in the vehicle differential gear which concerns on the 1st Embodiment of this invention. The graph which shows the result of having considered the tooth number reduction effect of the pinion gear in the vehicle differential gear which concerns on the 1st Embodiment of this invention. The flowchart shown in order to demonstrate the assembly method of the differential for vehicles which concerns on the 1st Embodiment of this invention. (a) And (b) is a perspective view shown in order to demonstrate the assembly method of the differential for vehicles which concerns on the 1st Embodiment of this invention. (A)-(d) is sectional drawing shown in order to demonstrate the process of other "incorporation of a side gear" in the assembly method of the differential for vehicles which concerns on the 1st Embodiment of this invention. Sectional drawing shown in order to demonstrate the differential for vehicles which concerns on the 2nd Embodiment of this invention. The flowchart shown in order to demonstrate the assembly method of the differential device for vehicles which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Differential gear for vehicles 2 ... Differential case, 2A ... Space part, 2b ... Pin mounting hole 3, 4 ... Pinion gear, 3A, 4A ... Gear body part, 30a, 40a ... 1st gear body part, 31a, 41a ... 1st 2 gear body, 30A, 40A ... second sliding surface, 31A, 41A ... non-sliding surface, 32A, 42A ... non-sliding surface, 3B, 4B ... gear collar, 30B, 40B ... first sliding surface 31B, 41B ... 3rd sliding surface, 3C, 4C ... gear part, 3D, 4D ... shaft insertion hole 5L, 5R ... side gear, 5La, 5Ra ... boss part, 5Lb, 5Rb ... gear part, 5Lc, 5Rc ... sliding Moving portions 6L, 6R ... spherical thrust washers 9L, 9R ... axle insertion holes, 9La, 9Ra ... side gear receiving portions, 9Lb, 9Rb ... thrust washer receiving portions 50 ... pinion gear shafts, 50A, 50B ... second pinion gear support surfaces, 50 ... Pin insertion holes 10, 11 ... Gear / shaft support part, 10A, 11A ... First pinion gear support face, 10B, 11B ... Pinion gear shaft support face, 10C, 11C ... Pinion gear receiving part 12L, 12R ... Side gear passage hole 13 ... Ring gear Mounting flange 52 ... Pin 100 ... Vehicle differential A A ... Bending part C ... Gear axis O ... Rotating axis D ... Gear flange outer diameter (flange diameter)
D1 ... diameter of tip circle D2 ... diameter of root circle t1 ... thickness of bent part t2 ... maximum thickness of gear collar

Claims (5)

Differential case,
A pair of side gears rotatably accommodated in the differential case;
A gear barrel having a gear shaft orthogonally meshed with the pair of side gears and having a shaft insertion hole provided in an axial center portion, a gear portion provided on an outer peripheral side of the gear barrel, and a gear of the gear portion At least one pair of pinion gears provided on the rear side over the entire circumference and having a gear flange portion formed integrally with the gear barrel portion and the gear portion and projecting to the outside of the gear barrel portion;
A pinion gear shaft inserted through the shaft insertion hole and supported by the differential case;
The differential case has at least one pair of pinion gear support portions that rotatably support the at least one pair of pinion gears by sliding with an outer peripheral surface of the gear flange portion;
The at least one pair of pinion gears does not include a supported portion with respect to the differential case, and the meshing portion with the pair of side gears is disposed closer to the rotation axis side of the differential case than the gear flange portion,
The gear base portion having a substantially T-shaped cross section composed of the gear flange portion and the gear body portion has a thickness at a bent portion thereof that is approximately the same as the maximum thickness of the gear flange portion,
The outer diameter of the gear collar is set smaller than the diameter of the tip of the meshing portion and larger than the diameter of the root of the meshing portion ,
When the outer diameter of the gear flange is D, the tooth tip circle diameter of the gear portion is D1, and the tooth root diameter D2 of the gear back side edge of the gear portion, the following inequality is satisfied. A vehicle differential.
D2 + (D1-D2) × 0.23 ≦ D ≦ D2 + (D1-D2) × 0.83   2. The vehicle differential device according to claim 1, wherein the at least one pair of pinion gears is formed by an annular body in which the gear flange portion has a uniform dimension in the gear axial direction along the circumferential direction.   3. The vehicle differential device according to claim 2, wherein the at least one pair of pinion gears is formed by an annular body in which the gear flange portion has an outer diameter that is uniform along the gear axial direction.   The pair of side gears has a sliding portion formed of a spherical surface that slides on an inner surface of the differential case on the back side, and a spherical center of the sliding portion is disposed on a rotation axis of the differential case. The vehicle differential device described in 1. Differential case,
A pair of side gears rotatably accommodated in the differential case;
A gear barrel having a gear axis orthogonally meshed with the pair of side gears and having a central axis as a gear axis, a gear portion provided on the outer peripheral side of the gear barrel, and a gear rear side of the gear portion And at least one pair of pinion gears that are provided over the circumference and have a gear flange portion that is formed integrally with the gear body portion and the gear portion so as to protrude to the outside of the gear body portion,
The differential case has at least one pair of pinion gear support portions that rotatably support the at least one pair of pinion gears by sliding with an outer peripheral surface of the gear flange portion;
The at least one pair of pinion gears does not include a supported portion with respect to the differential case, and the meshing portion with the pair of side gears is disposed closer to the rotation axis side of the differential case than the gear flange portion,
The gear base portion having a substantially T-shaped cross section composed of the gear flange portion and the gear body portion has a thickness at a bent portion thereof that is approximately the same as the maximum thickness of the gear flange portion,
The outer diameter of the gear collar is set smaller than the diameter of the tip of the meshing portion and larger than the diameter of the root of the meshing portion ,
When the outer diameter of the gear flange is D, the tooth tip circle diameter of the gear portion is D1, and the tooth root diameter D2 of the gear back side edge of the gear portion, the following inequality is satisfied. A vehicle differential.
D2 + (D1-D2) × 0.23 ≦ D ≦ D2 + (D1-D2) × 0.83

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