JP5120113B2 - Vehicle differential - Google Patents

Description

  The present invention relates to a vehicle differential, and more particularly, to a vehicle differential equipped with a pinion gear that receives a rotational driving force from a drive side, and a side gear that meshes with the pinion gear with a gear shaft orthogonal to each other.

  As a conventional vehicle differential device, a differential case that rotates by receiving engine torque, a pair of side gears that are parallel to each other along the rotation axis of the differential case, a pair of pinion gears that mesh with the pair of side gears, Some include a pinion gear shaft that supports the pair of pinion 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. In addition, the differential case is provided with a pair of axle insertion holes that communicate with the accommodation space and open in a direction perpendicular to the axis of the pair of pinion gears.

  The pair of side gears is composed of a bottomless cylindrical bevel gear having a boss portion and a gear portion, and is arranged so as to be movable along the rotation axis of the differential case, and the boss portion faces each of the axle insertion holes, and the differential case It is rotatably supported inside. In the pair of side gears, left and right axles are spline-fitted through the axle insertion holes.

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

  The pinion gear shaft is disposed in the housing space of the differential case, interposed between the pair of side gears, and is prevented from being detached by the pins.

  With the above configuration, when 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 its rotational 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 axles are connected to the pair of side gears 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, one pair Is transmitted to the left and right axles via the pinion gear and the pair of side gears.

  In this case, when the pair of pinion gears rotate, they slide on the support surfaces at both ends of the pinion gear shaft, so that frictional resistance is generated between each of these support surfaces and each of the pinion gears. Differential rotation is limited.

  Further, the rotation of the pair of pinion gears generates a thrust force at the meshing surfaces with the pair of side gears, and the thrust force moves the pair of side gears away from each other to the periphery of the inner opening of each axle insertion hole. Because of the pressure contact, a frictional resistance is generated between the pair of side gears and the inner peripheral edge of the pair of axle insertion holes, and the differential rotation of the pair of side gears is also limited by these frictional resistances.

  By the way, in this type of vehicle differential device, in order to obtain a sufficiently large differential limiting torque, it is important that the pinion gear frictionally slides with its axis parallel to the axis of the pinion gear shaft. The clearance between the inner peripheral surface of the shaft insertion hole and the support surface of the pinion gear shaft is set to a uniform dimension along the axis of the pinion gear shaft.

Thus, the reaction force from the pinion gear shaft against the pinion gear generated by the meshing of the pinion gear and the side gear during rotation of the differential case acts along the direction perpendicular to the axis, and while maintaining this state, the inner peripheral surface of the shaft insertion hole Frictionally slides on the support surface of the pinion gear shaft.
JP 2000-297856 A

  However, according to the conventional vehicle differential device in which the clearance between the pinion gear and the pinion gear shaft is set to be a uniform dimension along the axis of the pinion gear shaft, the pinion gear is caused by meshing with the side gear when the differential case rotates. Since the force is received from the pinion gear shaft and moves in a direction perpendicular to the axis, the tooth contact of the pinion gear with respect to the side gear has fluctuated. That is, the extension line of the gear shaft of the pinion gear does not intersect with the rotation axis of the side gear, and the rotation axis of the pinion gear shifts in a direction perpendicular to the central axis of the pinion gear shaft. There is a problem that not only the tooth surface strength is lowered due to the pressure increase on the tooth surface but also a stable differential limiting torque cannot be obtained.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a vehicle differential device that can suppress the occurrence of a decrease in tooth surface strength due to an increase in tooth surface pressure and can obtain a stable differential limiting torque. .

In order to achieve the above object, the present invention provides a pair of side gears and at least one pair of pinion gears that are meshed with the pair of side gears so that a gear shaft is orthogonal to each other and a shaft insertion hole is provided in the shaft center portion. A housing space for rotatably accommodating the at least one pair of pinion gears and the pair of side gears, and at least a part of the pair of pinion gears rotatably supported by sliding with an outer peripheral surface of the gears is an arc surface A differential case having a first pinion gear support portion, and a shaft inserted through the differential case and supported by the shaft insertion hole, and the at least one pair of pinion gears are rotatably supported by sliding on an inner peripheral surface of the shaft insertion hole. A pinion having a second pinion gear support portion at a position closer to the rotational axis of the differential case than the first pinion gear support portion. The at least one pair of pinion gears between the outer peripheral surface of the gear and the first pinion gear support portion when the pinion gear shaft and the center axis of the arc surface of the first pinion gear support portion coincide with each other. the clearance with a dimension C _1, the pinion shaft and the clearance dimension C ₂ between the inner peripheral surface and the second pinion gear supporting portion of the shaft insertion hole in the case where the central axis of the pinion gear shaft matches When, to provide a vehicle differential apparatus characterized by the dimension C ₁ is set to a larger dimension than the dimension C _2.

  According to the present invention, it is possible to suppress a decrease in tooth surface strength due to an increase in tooth surface pressure and to obtain a stable differential limiting torque.

[Embodiment]
FIG. 1 is a perspective view for explaining the entire vehicle differential device according to the embodiment of the present invention. FIG. 2 is a cross-sectional view for explaining the entire vehicle differential device according to the embodiment of the present invention. FIG. 3 is a graph shown for explaining the clearance between the pinion gear and the support surface of the vehicle differential according to the embodiment of the present invention. FIG. 4 is a cross-sectional view schematically showing a state where the axis of the pinion gear and the axis of the pinion gear shaft coincide with each other in the vehicle differential device according to the embodiment of the present invention. FIG. 5 is a cross-sectional view schematically showing a state in which the axis of the pinion gear is inclined with respect to the axis of the pinion gear shaft in the vehicle differential device according to the 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, A pair of pinion gears 3, 4 parallel to each other on the pinion gear shaft 50, a pair of side gears 5 L, 5 R meshing with the pair of pinion gears 3, 4 orthogonal to each other, and a pair of side gears 5 L, It is generally composed of a pair of thrust washers 6L and 6R located on the back side of 5R.

(Configuration of differential case 2)
As shown in FIGS. 1 and 2, the differential case 2 has an accommodation space 2A for accommodating the pinion gears 3 and 4 and the side gears 5L and 5R and the thrust washers 6L and 6R, and is entirely formed by a one-piece member. ing.

  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. . In addition, as shown in FIG. 1, the differential case 2 is a side gear located in a region that is symmetrical with respect to the rotation axis O and that is spaced from the gear shaft support portions 10 and 11 around the rotation axis O at equal intervals. Passing holes 12L and 12R 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. Thrust washer receiving portions 9La and 9Ra made of spherical surfaces that receive the thrust washers 6L and 6R are provided on the inner opening peripheral edges of the axle shaft 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. The first pinion gear support surfaces 10A and 11A are cylindrical (circumferential surfaces), but at least a part of the first pinion gear support surfaces 10A and 11A is a circular arc surface so that the pinion gears 3 and 4 are reliably supported when torque is transmitted between the differential case 2 and the pinion gears 3 and 4. What is necessary is just to be formed.

  The inner surfaces of the outer openings of the gear / shaft support portions 10 and 11 are arranged at positions farther from the rotation axis O of the differential case 2 than the first pinion gear support surfaces 10A and 11A, and both ends of the pinion gear shaft 50 rotate about the axis. It is formed by pinion gear shaft support surfaces 10B and 11B that are supported in a manner that cannot be moved in the axial direction.

  As shown in FIG. 2, pinion gear receiving 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 gear / shaft support 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 FIG. 1, the side gear passage holes 12 </ b> L and 12 </ b> R are formed by through holes having a planar non-circular opening. 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 a second pinion gear support surface 50A that rotatably supports the pinion gears 3 and 4 by sliding with inner peripheral surfaces of shaft insertion holes 3D and 4D (described later) of the pinion gears 3 and 4. , 50B through the pinion gears 3 and 4 (shaft insertion holes 3D and 4D) and supported by the pinion gear shaft support surfaces 10B and 11B of the differential case 2 (gear and shaft support portions 10 and 11). In this case, the pinion gear shaft 50 is fixed to the differential case 2 so that the outer peripheral surface thereof does not substantially have any gap between the pinion gear shaft support surfaces 10B and 11B. Then, as shown in FIG. 3 described in detail later, the diameter corresponding to the thermal expansion amount when compared with the normal temperature (20 °) due to the temperature rise caused by the frictional sliding of the second pinion gear support surfaces 50A and 50B. dimension _{D 2} is shown in a shaft insertion hole 3D, second sliding surface 30A of the 4D, 40A and a second pinion gear supporting surface 50A, the dimension clearance at room temperature between 50B _{C 2} (FIG. 4 of the pinion gear shaft 50 ) and when, is set to a dimension smaller than the dimension C _2. The size C ₂ is a clearance size in the case where the center axis of the gear shaft and the pinion shaft 50 of the pinion gear 3 match.

As for the pinion gear shaft 50, the second pinion gear support surfaces 50A and 50B and the second sliding surfaces 30A and 40A are used even when the maximum driving torque is applied to the differential case 2 in order to maintain the good support characteristics of the pinion gears 3 and 4. It is desirable that the clearance between the _two members has such a rigidity that the dimension C ₂ does not become zero.

  Second pinion gear support surfaces 50A and 50B are parallel to each other along the axis of first pinion gear support surfaces 10A and 11A and pinion gear shaft 50, and are spaced apart from gear and shaft support portions 10 and 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 FIG. 2, the pinion gear 3 includes a gear barrel portion 3A having a central axis as a gear axis C, a gear flange portion 3B as a first supported portion protruding outside the gear barrel portion 3A, and these gear barrels. The first pinion gear support surface of the gear shaft support surface 10 is composed of a bottomless cylindrical bevel gear having a gear portion 3C (meshing portion with the side gears 5L and 5R) located on the side gear side of the portion 3A and the gear flange portion 3B. 10A and the second pinion gear support surface 50A of the pinion gear shaft 50 are rotatably supported. The outer peripheral surface of the gear flange 3B is formed in a cylindrical shape (cylindrical surface), and is configured as a first sliding surface 30B that frictionally slides with the first pinion gear support surface 10A. Then, as shown in FIG. 3, the radial dimension D ₁ corresponding to the amount of thermal expansion when compared to the normal temperature by the temperature rise due to frictional sliding, etc. of the gear collar portion 3B is first sliding surface 30B If the clearance at normal temperature between the first pinion gear support surface 10A and the first pinion gear support surface 10A is a dimension C ₁ (shown in FIG. 4), the dimension is set to be smaller than the dimension C ₁ . The size C ₁ is a clearance size in the case where the center axis of the arcuate surface of the the gear shaft of the pinion gear 3 first pinion gear supporting surface 10A matches.

Here, in FIG. 3, a point where the rotation axis O of the differential case 2 and the axis S of the pinion gear shaft 50 intersect is defined as an intersection (conical vertex) a (shown in FIG. 4), and the intersection a and the first sliding surface 30B. The horizontal axis is the distance between the load center point and the load center point of the second sliding surface 30A, and between the first sliding surface 30B and the first pinion gear support surface 10A and between the second sliding surface 30A and the second pinion gear. It is the figure which showed these relationships typically by making clearance between 50 A of support surfaces into a vertical axis | shaft. As described above, the clearance dimensions C ₁ and C ₂ must be larger than the radial dimensions D ₁ and D ₂ corresponding to the amount of thermal expansion. Good contact between the surface 30B and the first pinion gear support surface 10A and the second sliding surface 30A and the second pinion gear support surface 50A cannot be obtained. Therefore, it is desirable to set the clearance dimensions C ₁ and C ₂ within the range of the area A in FIG.

  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. It is formed by a cylindrical body composed of 30a and a second gear body 31a having a substantially truncated cone shape.

As shown in FIG. 2, the shaft insertion hole 3 </ b> D is formed by a round hole having two large and small inner surfaces with different inner diameters. Of the inner surfaces of the shaft insertion hole 3D, the inner surface having the smaller inner diameter is disposed closer to the rotational axis O of the differential case 2 than the other inner surfaces having the larger inner diameter, and slides on the second pinion gear support surface 50A of the pinion gear shaft 50. 2 It is formed by the second sliding surface 30A as a supported portion. As shown in FIG. 4, a point where the rotational axis O of the differential case 2 and the axis S of the pinion gear shaft 50 intersect is defined as an intersection (conical vertex) a, and the intersection a and the load center of the second sliding surface 30A. When a virtual line length of (cone generatrix) V ₂ connecting the point and L _2, the dimension C ₂ in proportion to the size L ₂ is set. In FIG. 4, the symbol R indicates the moving direction of the pinion gear 3.

  On the other hand, the inner surface having a larger inner diameter among the inner surfaces of the shaft insertion hole 3D is disposed at a position 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 a moving surface 31A. The opening on the gear back side of the shaft insertion hole 3D is formed by a trumpet-shaped opening that gradually expands from the gear axial direction intermediate portion toward the gear back side. The non-sliding surface 31A does not slide on the outer peripheral surface of the pinion gear shaft 50, and is connected to the tapered surface 31a connected to the second sliding surface 30A, and the tapered surface 31a and the gear back side end surface of the gear flange 3B. It is formed by a gently curved surface 32a that is connected.

  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.

The outer peripheral surface of the gear flange 3B is formed by a first sliding surface 30B as a first supported portion that slides on the first pinion gear support surface 10A of the gear / shaft support surface 10. Then, as shown in FIG. 4, the intersection a and the virtual line length of (cone generatrix) V ₁ connecting the load center point of the first sliding surface 30B and the dimension L _1, proportional to the size L ₁ dimensioned C ₁ and is set. That is, the ratio of L ₁ and L ₂ is equal to the ratio of C ₁ and C ₂ .

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

  As shown in FIG. 2, 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 rotational 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.

(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). A bevel gear having a diameter and a single tip cone angle, which is rotatably supported in the housing space 2A of the differential case 2 and is configured to mesh with the pinion gears 3 and 4.

  Sliding portions 5Lc and 5Rc made of spherical surfaces that are fitted to the thrust washer receiving portions 9La and 9Ra via the thrust washers 6L and 6R are provided on the rear surfaces of the side gears 5L and 5R. 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.

(Configuration of thrust washers 6L and 6R)
As shown in FIG. 2, the thrust washers 6L and 6R are annular washers that adjust the meshing between the side gears 5L and 5R and the pinion gears 3 and 4, and the sliding portions 5Lc and 5Rc of the side gears 5L and 5R and the thrust washer receiver It is interposed between the parts 9La and 9Ra. The left and right axles are respectively inserted so as to receive the thrust force of the side gears 5L and 5R. The thrust washers 6L and 6R are provided with a lubricating oil introduction path (not shown) for introducing lubricating oil from the inner periphery of the washer to the outer periphery of the washer.

[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.

At this time, as shown in FIG. 4, the first sliding surface 30B, 40B and the first pinion gear supporting surfaces 10A, dimension _{C 1} Clearance intersections a and first pinion gear supporting surface 10A between 11A, 11A load the length _{L 1} of the virtual line _{V 1} connecting the center point, and the second sliding surface 30A, 40A and a second pinion gear supporting surfaces 50A, clearance dimension _{C 2} intersection a second pinion gear supporting surfaces of the 50B Since these are set in proportion to the length L ₂ of the imaginary line V ₂ connecting the load center points 30A and 40A, the side gears 5L and 5R (shown in FIG. 2) and the pinion gears 3 and 4 (only the pinion gear 3 is shown) ), When a load acts on the pinion gears 3 and 4 from the side gears 5L and 5R, the pinion gears 3 and 4 (only the pinion gear 3 is shown) as shown in FIG. Tilted in the direction R to the rotation of the axis line. Accordingly, the load center point of the first sliding surfaces 30B and 40B and the load center point of the second sliding surfaces 30A and 40A are respectively in predetermined positions, that is, the first sliding surfaces 30B and 40B and the first pinion gear. support surfaces 10A, clearance dimensions _C'1 intersection a and first pinion gear supporting surface 10A between 11A, the imaginary line _V'1 connecting the load center point of 11A to the length _L'1, and the second sliding surfaces 30A, 40A and the length of the imaginary line _V'2 in which the second pinion gear supporting surfaces 50A, clearance dimension _C'2 and 50B connecting the intersection a second pinion gear supporting surface 30A, and a load center point of 40A It moves to a position set in proportion to L′ ₂ . As a result, the tooth contact of the pinion gears 3 and 4 with respect to the side gears 5L and 5R does not fluctuate, and the pinion gears 3 and 4 and the side gears 5L and 5R are engaged at the theoretical engagement position.

  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, so that there is friction between the thrust washers 6L, 6R and the side gears 5L, 5R. Resistance is generated, 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 due to 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.

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

(1) Since the meshing between the pinion gears 3 and 4 and the side gears 5L and 5R is performed at a theoretical meshing position, it is possible to suppress a decrease in tooth surface strength due to an increase in tooth surface pressure and a stable differential. A limiting torque can be obtained.

(2) Since the gear back side openings of the shaft insertion holes 3D and 4D in the pinion gears 3 and 4 are formed by trumpet-shaped openings having gentle curved surfaces 32a and 42a, the rigidity of the pinion gears 3 and 4 is made uniform. And relatively high tooth surface strength can be obtained.

  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 the present embodiment, the case where two (one pair) pinion gears 3 and 4 are arranged in the differential case 2 has been described. However, the present invention is not limited to this, and three or more pinion gears are provided in the differential case. You may arrange in.

(2) In the present embodiment, the case where the differential case 2 is formed by a one-piece member has been described. However, the present invention is not limited to this, and may be a differential case composed of a plurality of case elements.

The perspective view shown in order to demonstrate the whole vehicle differential gear which concerns on embodiment of this invention. Sectional drawing shown in order to demonstrate the whole vehicle differential device which concerns on embodiment of this invention. The graph shown in order to demonstrate the clearance between the pinion gear of the vehicle differential device which concerns on embodiment of this invention, and its support surface. Sectional drawing which shows typically the state in which the axis line of the pinion gear and the axis line of the pinion gear shaft correspond in the vehicle differential device which concerns on embodiment of this invention. FIG. 3 is a cross-sectional view schematically showing a state in which the axis of the pinion gear is inclined with respect to the axis of the pinion gear shaft in the vehicle differential device according to the embodiment of the present 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, 31a, 41a ... tapered surface, 32a, 42a ... curved surface, 3B, 4B ... gear collar, 30B, 40B ... first 1 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 part 6L, 6R ... Thrust washer 9L, 9R ... Axle insertion hole, 9La, 9Ra ... Thrust washer receiving part 50 ... Pinion gear shaft, 50A, 50B ... Second pinion gear support surface, 50D ... Pin insertion hole DESCRIPTION OF SYMBOLS 10,11 ... Gear shaft support part, 10A, 11A ... 1st pinion gear support surface, 10B, 11B ... Pinion gear shaft support surface, 10C, 11C ... Pinion gear receiving part 12L, 12R ... Side gear passage hole 13 ... Flange for ring gear attachment a ... intersection C ... axis of the gear axis S ... pinion shaft _{C 1, C 2, C'1} , C'2 ... dimension V _{1, V} 1 clearance, _{V'1, V'2} ... imaginary line L _{1, L 2} , L ′ ₁ , L ′ ₂ ... virtual line length O ... rotation axis L ... load F1, F2 ... reaction force

Claims (5)

A pair of side gears;
At least one pair of pinion gears that are meshed with the pair of side gears so that a gear shaft is orthogonal to each other, and a shaft insertion hole is provided in an axial center portion;
An accommodation space for rotatably accommodating the at least one pair of pinion gears and the pair of side gears, and at least a part of the pair of pinion gears rotatably supported by sliding with an outer peripheral surface of the gears from an arc surface A differential case having a first pinion gear support,
A second pinion gear support portion that is supported by inserting the shaft insertion hole into the differential case and that rotatably supports the at least one pair of pinion gears by sliding with an inner peripheral surface of the shaft insertion hole is the first pinion gear support portion. A pinion gear shaft having a position closer to the rotational axis of the differential case than
The at least one pair of pinion gears has a clearance C between the gear outer peripheral surface and the first pinion gear support portion when the pinion gear shaft and the center axis of the arc surface of the first pinion gear support portion coincide with each other. ₁ and when the clearance between the inner peripheral surface of the shaft insertion hole and the second pinion gear support portion when the pinion gear shaft and the center axis of the pinion gear shaft coincide with each other is a dimension C ₂ , vehicle differential apparatus characterized by C ₁ is set to a larger dimension than the dimension C _2. In the differential case, the first pinion gear support portion is disposed at a position farther from the rotational axis than the engagement center point of the at least one pair of pinion gears and the pair of side gears in the axial direction of the pinion gear shaft.
In the pinion gear shaft, at least a part of the second pinion gear support portion is disposed at a position closer to the rotational axis than the meshing center point of the at least one pair of pinion gears and the pair of side gears in the axial direction. The vehicle differential device according to claim 1. The at least one pair of pinion gears includes a first supported portion corresponding to the first pinion gear support portion and a second supported portion corresponding to the second pinion gear support portion, and the rotation axis of the differential case and the pinion gear the point of intersection is the axis of the shaft as well as the intersection a, and the intersection point a and the length of the first imaginary line connecting the supported portion and the dimensions L _1, and the said intersection a second supported portion When the length of the imaginary line and the dimension L ₂ connecting the dimension C ₂ is the dimensioned L _1, also according to claim 1, wherein the dimension C ₁ is set in proportion to each of the dimensions L ₁ A differential for a vehicle.   4. The vehicle differential device according to claim 3, wherein the at least one pair of pinion gears are configured such that the first supported portion and the second supported portion are arranged at a predetermined interval in an axial direction of the pinion gear shaft. Pinion gear of said at least one pair of radial dimension corresponding to the amount of thermal expansion due to seizure of the gear outer peripheral surface is set to a dimension smaller than the dimension C _1,
2. The vehicle differential device according to claim 1, wherein the pinion gear shaft has a radial dimension corresponding to a thermal expansion amount due to seizure of the second pinion gear support portion smaller than a dimension C ₂ .

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