JP2010078001A - Differential apparatus for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a differential apparatus for vehicle, which can prevent baking and biased wear in a pinion gear and differential case from occurring, and obtain an excellent engaging condition between the pinion gear and differential case. <P>SOLUTION: Pinion gears 3 and 4, which are engaged by crossing a gear shaft with side gears 5R and 5L, have gear sections 31 and 41 receiving a reaction force followed by torque transmission toward the side gears 5R and 5L. Furthermore, the pressure angle of the gear sections 31 and 41 is set to be an angle that the line of action through the resultant force of reaction forces from the side gears 5R and 5L is always crossed with first supported sections 3a and 4a, the second supported sections 3b and 4b and the first pinion gear supporting surfaces 10a and 11a of a differential case 2, or second pinion gear supporting surfaces 10b and 11b. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle differential, and more particularly to a vehicle differential having a plurality of pinion gear support portions that slidably support a plurality of shaftless pinion gears.

  As a conventional vehicle differential device, for example, there is one provided with a pair of pinion gears of a shaftless type (Patent Document 1).

  The vehicle differential device includes a pair of pinion gears, a pair of side gears meshed with the pair of pinion gears, and a differential case that rotatably accommodates the pair of side gears and the pair of pinion gears. Yes.

  The pair of pinion gears includes a first sliding portion provided on the entire circumference of the gear, a gear meshing portion meshing with the pair of side gears, and a second sliding provided on a part of the gear meshing portion in the circumferential direction. It has a moving part and is arranged on an axis perpendicular to the rotation axis of the differential case.

  The pair of side gears is formed of a substantially annular bevel gear having an outer diameter larger than the outer diameter of the pinion gear, and is disposed on the rotation axis of the differential case. The left and right axles are connected to the inner surfaces of the pair of side gears by spline fitting, respectively.

  The differential case is provided with a pair of pinion gear insertion holes having a first pinion gear support surface that slidably supports the first sliding portions of the pair of pinion gears. A pair of extending portions each having a second pinion gear support surface that slidably supports a second sliding portion of the pair of pinion gears is provided on the inner opening periphery of the pair of pinion gear insertion holes.

  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, and further transmitted from the pair of pinion gears to the pair of side gears. Since the left and right axles are connected to the pair of side gears by spline fitting, the torque from the engine side is distributed to the left and right according to the running condition of the vehicle, and the distributed torque is transmitted to the left and right axles. The

  In this case, when a pair of pinion gears rotates, the first pinion gear support surface of each pinion gear insertion hole slides on the second pinion gear support surface of each extension portion, and therefore, frictional resistance is generated between these support surfaces. The frictional resistance limits the differential rotation of the pair of side gears.

  In addition, the pair of pinion gears rotates to generate a thrust force on the meshing surfaces with the pair of side gears, and the thrust force moves the pair of side gears away from each other so as to move to the inner peripheral edge of each axle insertion hole. Because of the pressure contact, a frictional resistance is generated between the pair of side gears and the inner opening periphery 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, for example, when the vehicle turns while a large torque is transmitted to the differential case, the first sliding portion and the second sliding portion of the pinion gear are connected to the first pinion gear insertion hole. The first pinion gear support surface and the second pinion gear support surface of the extension part slide while being pressed. At this time, the areas where the first sliding portion and the second sliding portion are supported by the first pinion gear support surface and the second pinion gear support surface are different depending on the rotational phase of the pinion gear.
JP 2007-1113747 A

  However, according to the vehicle differential shown in Patent Document 1, the pinion gear is counteracted from the differential case (the first pinion gear support surface and the second pinion gear support surface) to the first sliding portion and the second sliding portion by the rotational phase. Tilt by force. Therefore, while the pinion gear is tilted, it slides while pressing the first pinion gear support surface and the second pinion gear support surface, and not only the pinion gear or the differential case is seized or unevenly worn, but also the pinion gear and the side gear are in good meshing state. There was a problem that could not get.

  Accordingly, an object of the present invention is to provide a vehicle differential device that can suppress the occurrence of seizure and uneven wear in the pinion gear and the differential case, and can obtain a good meshing state between the pinion gear and the side gear. is there.

  In order to achieve the above object, the present invention provides a pair of side gears, a plurality of pinion gears that mesh with the pair of side gears with a gear shaft orthogonal thereto, and that have a sliding surface on the outer periphery of the gear, A differential case having a pinion gear support portion that accommodates the pinion gear and the pair of side gears and rotatably supports the plurality of pinion gears by sliding on the sliding surface, and the plurality of pinion gears includes the pair of side gears. A gear meshing portion that receives a reaction force accompanying torque transmission to the gear, and the pressure angle of the gear meshing portion is set to an angle that always causes the line of action due to the resultant force of the reaction force to intersect the sliding surface and the pinion gear support portion Provided is a vehicle differential.

  According to the present invention, the occurrence of seizure and uneven wear in the pinion gear and the differential case can be suppressed, and a good meshing state between the pinion gear and the side gear can be obtained.

[Embodiment]
FIG. 1 is an exploded perspective view for explaining a vehicle differential according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view for explaining the vehicle differential according to the embodiment of the present invention. FIG. 3 is a cross-sectional view shown for explaining the vehicle differential according to the embodiment of the present invention. FIG. 4 is a cross-sectional view showing an assembled state of the pinion gear of the vehicle differential device according to the embodiment of the present invention. FIG. 5 is a perspective view showing a differential case of the vehicle differential gear according to the embodiment of the present invention. FIG. 6 is a cross-sectional view for explaining the pinion gear in the vehicle differential device according to the embodiment of the present invention.

[Overall configuration of vehicle differential device]
1 to 3, a vehicle differential device denoted by reference numeral 1 includes a differential case 2 that rotates in response to engine torque, and a pair of upper and lower pairs that are parallel to each other along an axial direction orthogonal to the rotational axis O of the differential case 2. The pinion gears 3 and 4, a pair of left and right side gears 5 L and 5 R meshing with the pinion gears 3 and 4, and thrust washers 6 L and 6 R located on the back side of the side gears 5 L and 5 R are roughly configured.

(Configuration of differential case 2)
As shown in FIGS. 2 and 4, 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 thrust washers 6 </ b> L, 6 </ b> R. Is formed.

  As shown in FIGS. 2 and 4, the differential case 2 has a pair of left and right axle insertion holes 9L and 9R that open along the rotational axis O, and an axis line in a direction perpendicular to the axis lines of the axle insertion holes 9L and 9R. And a pair of upper and lower pinion gear support portions 10 and 11 are provided. Further, as shown in FIG. 4, the differential case 2 is a region that is symmetrical with respect to the rotation axis O (shown in FIG. 2), and is located at a portion that is spaced apart from the pinion gear support portions 10 and 11 at equal intervals in the circumferential direction. Side gear passage holes 12L and 12R are provided. As shown in FIGS. 1 to 3, an annular ring gear mounting flange 13 is integrally provided on the left axle side of the differential case 2 along the circumferential direction in a plane perpendicular to the rotation axis O.

  As shown in FIGS. 2 and 3, the axle insertion holes 9L and 9R are formed by through holes having a uniform inner diameter. Left and right axles (not shown) are inserted through the axle insertion holes 9L and 9R, respectively. Thrust washer receiving portions 9La and 9Ra made of spherical surfaces for receiving the thrust washers 6L and 6R are provided on the inner peripheral edges of the axle insertion holes 9L and 9R.

  As shown in FIG. 4, the pinion gear support portions 10 and 11 are formed by pinion gear back holes 10A and 11A and extending portions 10B and 11B.

  As shown in FIG. 4, the pinion gear back holes 10A, 11A are formed by stepped through holes communicating with the space 2A. And it is comprised so that it may function as a pinion gear support hole and a pinion gear processing hole. The inner opening size of the pinion gear back holes 10A and 11A is set to a size having 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 pinion gear back holes 10A and 11A are respectively from circumferential surfaces that support the first supported portions (portions excluding the gear meshing portions with respect to the side gears 5L and 5R) 3a and 4a of the pinion gears 3 and 4 so as to be slidable and rotatable. The pinion gear support surfaces (first pinion gear support surfaces) 10a and 11a are formed.

  As shown in FIGS. 2 and 4, the pinion gear back holes 10 </ b> A and 11 </ b> A receive pinion gears 3 and 4 on which centrifugal force acts and pinion gear receivers formed of spherical surfaces having a predetermined curvature. Portions (tops) m and n are provided. Washer receiving portions 10C and 11C for receiving washers 21 and 22 as plugs are provided on the second stepped surfaces of the pinion gear back holes 10A and 11A. As shown in FIGS. 2 and 4, the washers 21 and 22 are interposed between the back surfaces of the pinion gears 3 and 4 and the washer receiving portions 10c and 11c. The pinion gear back holes 10 </ b> A and 11 </ b> A are closed, and the lubricating oil that receives centrifugal force due to the rotation of the differential case 2 is blocked. Thereby, it is avoided that the lubricating oil in the differential case 2 flows out of the differential case 2 through the pinion gear back holes 10A and 11A.

  At the periphery of the inner opening of the pinion gear back hole 10A, as shown in FIG. 4, there are extended portions 10B and 10B that are arranged in parallel at equal intervals around the axis and extend toward the rotation axis of the differential case 2 (inside the case). It is provided integrally. The extension portions 10B and 10B are connected to the pinion gear support surface 10a and part of the first supported portion 3a of the pinion gear 3 and the second supported portion of the pinion gear 3 (one of the gear meshing portions with respect to the side gears 5L and 5R). Part) 3b is provided with a pinion gear support surface (second pinion gear support surface) 10b composed of an arcuate surface that slidably and rotatably supports.

  Similarly, at the periphery of the inner opening of the pinion gear back hole 11A, as shown in FIG. 4, an extension portion 11B is arranged in parallel around the axis line at equal intervals and extends toward the rotation axis side (inside the case) of the differential case 2. , 11B are integrally provided. The extension portions 11B and 11B are connected to the pinion gear support surface 11a and part of the first supported portion 4a of the pinion gear 4 and the second supported portion of the pinion gear 4 (one of gear engaging portions with respect to the side gears 5L and 5R). Part) 4b is provided with a pinion gear support surface (second pinion gear support surface) 11b composed of an arcuate surface that slidably and rotatably supports.

  As shown in FIGS. 3 to 5, 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 gears 3 and 4)
Since the pinion gears 3 and 4 have substantially the same configuration, for example, only the pinion gear 3 will be described. As shown in FIGS. 2 and 4, the pinion gear 3 has a substantially T-shaped cross section with the gear axis C as the central axis. It has a gear portion 31 that is a gear meshing portion with the base end portion 30 and the side gears 5L and 5R, and is composed of a substantially cylindrical shaftless gear with six teeth (six teeth), for example, and the back surface of the pinion gear The first pinion gear support surface 10a of the hole 10A and the second pinion gear support surfaces 10b and 10b of the extending portions 10B and 10B are rotatably supported.

  As shown in FIG. 6, the pinion gear 3 (gear portion 31) receives reaction force associated with torque transmission to the side gears 5 </ b> L and 5 </ b> R at its tooth surface, and an action line P due to the resultant force of these reaction forces is applied to the first supported portion. The pressure angle is set to an angle that always intersects 3a or the second supported portion 3b and the first pinion gear support surface 10a or the second pinion gear support surface 10b. For this reason, the meshing center point G of the tooth surfaces of the pinion gear 3 (gear portion 31) (the load center in the region where the tooth surfaces of both gears contact when the torque is transmitted from the pinion gears 3 and 4 to the side gears 5L and 5R) The gear radial dimension up to a support part (described later) 3a is a, and the gear axial dimension from the meshing center point G of the tooth surface of the gear part 31 to the gear tip end side of the gear part 31 is b. Further, the gear axial direction dimension from the gear tip end side end portion of the first supported portion 3a to the gear tip end side end portion of the gear portion 31 is set to c, and the gear back side of the first supported portion 3a Assuming that the dimension in the gear axis direction from the endmost part to the gear tip end side end part of the gear portion 31 is d, the pressure angle α of the pinion gear 3 is set to an angle satisfying c <b + a × tanα <d.

  The pressure angle of the pinion gear 3 acts on the first pinion gear support surface 10a and the second pinion gear support surface 10b from the first supported portion 3a and the second supported portion 3b of the pinion gear 3 when the vehicle differential 1 is driven. In order to reduce the tilt of the pinion gear 3 by increasing the load point to be applied, it is desirable to set the angle as large as possible so that the manufacture of the pinion gear 3 does not become difficult.

  The pinion gear 3 has a lubricating oil that opens to a first supported portion 3a (described later) with respect to the first pinion gear support surface 10a of the second pinion gear support surface 10b, 10b of the extension portions 10B, 10B and the first pinion gear support surface 10a of the pinion gear back hole 10A. A plurality of concave grooves (not shown) are provided as inflow portions.

  The pinion gear 3 is provided with a through hole 3A that opens in the gear axis direction. Thereby, not only the outer surface of the pinion gear 3 but also the inner surface of the through hole 3A can be heat-treated, and the mechanical strength of the pinion gear 3 can be further increased. The through hole 3A is configured to function as a centering hole when the pinion gear is formed, a lubricating oil supply hole when using the differential gear, and a gear support rod insertion hole when storing the pinion gear.

  The base end portion 30 constitutes a gear body portion and a gear flange portion of the pinion gear 3 and is formed at a portion excluding a gear meshing portion that meshes with the side gears 5L and 5R. A first pinion gear support surface 10a of the pinion gear back hole 10A and a second peripheral surface corresponding to a part of the second pinion gear support surfaces 10b, 10b of the extension portions 10B, 10B are disposed on the upper outer peripheral surface of the base end portion 30. A first supported portion 3a is provided as one sliding surface. On the back surface of the pinion gear 3, there is provided a sliding portion 3B formed of a spherical surface that matches the pinion gear receiving portion m of the pinion gear back surface hole 10A.

  The gear portion 31 is integrally provided on the side gear side of the base end portion 30, and is configured to mesh with the side gears 5 </ b> L and 5 </ b> R on the rotation axis side of the differential case 2. The gear portion 31 is provided with a second supported portion 3b as a second sliding surface corresponding to the second pinion gear support surfaces 10b, 10b of the extending portions 10B, 10B. The second supported portion 3b is continuously arranged at a part around the gear axis C to the first supported portion 3a of the base end portion 30, and is formed by an arc surface having a predetermined outer diameter.

(Configuration of side gears 5L, 5R)
As shown in FIG. 2, the side gears 5L and 5R are substantially annular gears having boss portions 5La and 5Ra and gear portions 5Lb and 5Rb having different outer diameters (having an outer diameter larger than the outer diameter of the pinion gears 3 and 4). And a bevel gear having a single tooth tip cone angle, and is rotatably supported in the differential case 2 and meshed with the pinion gears 3 and 4. The number of teeth of the side gears 5L and 5R is set to 2.1 or more times the number of teeth of the pinion gears 3 and 4. The outer diameters of the side gears 5L and 5R are set to be larger than the outer diameter of the pinion gears 3 and 4 and the dimension between the extending portions 10B and 11B.

  Sliding portions 5Lc and 5Rc made of spherical surfaces that are fitted to the thrust washer receiving portions 9Lc and 9Rc 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 are spline-fitted through the axle insertion holes 9L and 9R, respectively. As shown in FIGS. 2 and 3, an axle spacer 23 as an axle movement restricting member is interposed between the side gears 5L and 5R.

(Configuration of thrust washers 6L and 6R)
As shown in FIGS. 1 to 3, the thrust washers 6L and 6R are annular washers having washer bodies 6La and 6Ra that receive the thrust force of the side gears 5L and 5R, and the back surfaces of the side gears 5L and 5R and the thrust washer receiving portions. It is interposed between 9Lc and 9Rc. And it is comprised so that mesh | engagement with the side gears 5L and 5R and the pinion gears 3 and 4 may be adjusted. The outer peripheral edges of the thrust washers 6L and 6R are integrally provided with plastically deformable substantially scissors-like locking pieces 26 and 27 that are arranged in parallel at equal intervals in the circumferential direction.

  The locking pieces 26 and 27 are plastically deformed and locked to the outer peripheral surfaces of the side gears 5L and 5R, and are disposed at positions that allow the side gears 5L and 5R to rotate. And it is comprised so that the position shift of the radial direction of the thrust washers 6L and 6R with respect to the side gears 5L and 5R may be prevented.

[Operation of the differential 1 for a vehicle]
First, 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 is rotated about the rotation axis O. Next, when the differential case 2 is rotated, this rotational force is transmitted to the pinion gears 3 and 4 and further transmitted from the pinion gears 3 and 4 to the side gears 5L and 5R.

  Here, when the loads applied to the wheels on the left and right axles are equal, when torque from the engine side is transmitted to the differential case 2, the pinion gears 3, 4 revolve on the side gears 5L, 5R, and the pinion gears 3, 4 and the side gears 5L, 5R are rotated together with the differential case 2, so that torque from the engine side is equally transmitted to the left and right axles, and the left and right wheels are rotated at the same rotational speed.

  On the other hand, when the vehicle turns to the left, for example, or the right wheel falls into a muddy state while traveling, the pinion gears 3 and 4 rotate while meshing with the side gears 5L and 5R, and the torque from the engine side is increased. Differential distribution between left and right axles (wheels). That is, the left wheel is rotated at a speed lower than the rotational speed of the differential case 2, and the right wheel is rotated at a speed higher than the rotational speed of the differential case 2.

  Further, when the pinion gears 3 and 4 rotate when torque is applied to the differential case 2, the first pinion gear support surfaces 10a and 11b slide on the first pinion gear support surfaces 10a and 11a and the second pinion gear support surfaces 10b and 11b. Friction resistance is generated between 11a and the second pinion gear support surfaces 10b and 11b, and differential rotation of the side gears 5L and 5R is limited by these frictional resistances.

  In this case, a thrust force in the direction of the rotation axis of each gear is generated on the meshing surfaces with the side gears 5L and 5R by the rotation of the pinion gears 3 and 4. Since the side gears 5L and 5R move away from each other by the thrust force generated in the side gears 5L and 5R and the thrust washers 6L and 6R are pressed against the thrust washer receiving portions 9Lc and 9Rc, the thrust washers 6L and 6R and the thrust washer receiver Friction resistance is generated between the portions 9Lc and 9Rc, and the differential rotation of the side gears 5L and 5R is also limited by these frictional resistances. In addition, since the sliding portions 3B and 4B of the pinion gears 3 and 4 are pressed against the pinion gear receiving portions m and n of the differential case 2 by the thrust force generated in the pinion gears 3 and 4, frictional resistance against rotation of the pinion gears 3 and 4 is generated. This also restricts the differential rotation of the side gears 5L and 5R.

  In the present embodiment, for example, when the vehicle turns while a large torque is transmitted to the differential case 2, the differential case 2 (the first pinion gear support surfaces 10a and 11a and the second pinion gear support surfaces 10b and 11b) Even if the pinion gears 3 and 4b are tilted by the reaction force to the first supported portions 3a and 4a and the second supported portions 3b and 4b in the pinion gears 3 and 4, these reaction forces are shown in FIGS. 7A and 7B. As shown in FIG. 8, the second pinion gear support surfaces 10b and 11a are connected to the first pinion gear support surface 10a via the second sliding portions 3b and 4b (only one is shown) and as shown in FIGS. 11a is received through the first sliding portions 3a and 4a (only one is shown), and the tilting of the pinion gears 3 and 4 can be reduced.

  FIGS. 7A and 7B are a front view and a bottom view, respectively, for explaining a one-tooth contact state of the pinion gear with respect to the differential case in the vehicle differential device according to the embodiment of the present invention. FIG. 7A shows a front view, and FIG. 7B shows a side view. FIGS. 8A and 8B are a front view and a bottom view for explaining the two-tooth contact state of the pinion gear with respect to the differential case in the vehicle differential device according to the embodiment of the present invention. FIG. 8A shows a front view, and FIG. 8B shows a side view.

  Here, (1) surface pressure reduction effect and (2) tilt reduction effect in the case of the pinion gear 3 (number of teeth 6) in the vehicle differential device 1 shown in the present embodiment will be described with reference to FIGS. Consider a pinion gear with other number of teeth (7).

(1) Consideration about the effect of reducing the surface pressure This consideration is performed by performing a numerical simulation by a finite element method (FEM) to perform the first pinion gear support surfaces 10a and 11a and the second pinion gear support surface 10b of the differential case 2. An attempt was made by calculating the surface pressure experienced by 11b.

  As a result, the first pinion gear due to the sliding of the first supported portions 3a, 4a and the second supported portions 3b, 4b of the pinion gears 3, 4 with the rotational phase at the circumferential center position of the extending portions 10B, 11B being 0 °. When the maximum surface pressure Pf at a predetermined circumferential position on the support surfaces 10a and 11a or the second pinion gear support surfaces 10b and 11b was calculated, a numerical value in the range of 75 MPa <Pf <105 MPa was obtained.

  On the other hand, in the case of a pinion gear having 7 teeth, the maximum surface pressure Pf was obtained in a range of 51 MPa <Pf <125 MPa.

  Accordingly, it was confirmed that the pinion gears 3 and 4 having 6 teeth have a surface pressure reducing effect as compared with the case of the pinion gear having 7 teeth.

  This is as shown in FIG. 9 and FIG. 9 and 10 are graphs showing the results of considering the surface pressure reduction effect of the pinion gear in the vehicle differential device according to the embodiment of the present invention. FIG. 9 is a graph for explaining the effect of reducing the surface pressure of the pinion gear having 6 teeth, and FIG. 10 is a graph for explaining the effect of reducing the surface pressure of the pinion gear having 7 teeth. 9 and 10, the vertical axis represents pressure (MPa), and the horizontal axis represents rotational phase (°).

  The effect of reducing the surface pressure is the same as that of a pinion gear with 6 teeth when it is a pinion gear with 9 teeth, and with a pinion gear with 8 teeth. Each was obtained in the same manner as in the case of 7 sheets.

(2) Consideration on tilt reduction effect This study was attempted by calculating the tilt angle of the pinion gear (gear axis) with respect to the axis of the pinion gear back holes 10A and 11A by performing a numerical simulation by the finite element method (FEM). .

  As a result, the first pinion gear due to the sliding of the first supported portions 3a, 4a and the second supported portions 3b, 4b of the pinion gears 3, 4 with the rotational phase at the circumferential center position of the extending portions 10B, 11B being 0 °. When the maximum inclination θ with respect to the axis of the pinion gear back hole 10A, 11A at a predetermined circumferential position on the support surfaces 10a, 11a or the second pinion gear support surfaces 10b, 11b is calculated, the maximum inclination angle θ is 0.05 ° <θ <. A numerical value in the range of 0.075 ° was obtained.

  On the other hand, in the case of a pinion gear having 7 teeth, a maximum inclination angle θ was obtained in a range of −0.01 ° <θ <0.125 °.

  Accordingly, it was confirmed that the pinion gears 3 and 4 having 6 teeth have a tilt reduction effect as compared with the case of the pinion gear having 7 teeth.

  This is as shown in FIG. 11 and FIG. FIGS. 11 and 12 are graphs showing the results of considering the tilt reduction effect of the pinion gear in the vehicle differential device according to the embodiment of the present invention. FIG. 11 is a graph for explaining the tilt reduction effect of the pinion gear with six teeth, and FIG. 12 is a graph for explaining the tilt reduction effect of the pinion gear with seven teeth. 11 and 12, the vertical axis represents the tilt angle (°), and the horizontal axis represents the rotational phase (°).

  This tilt reduction effect is similar to the case of a pinion gear with 6 teeth when it is a pinion gear with 9 teeth, and the number of teeth when it is a pinion gear with 8 teeth. Was obtained in the same manner as in the case of 7 sheets.

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

  Since the surface pressure and tilt due to the rotation phase of the pinion gears 3 and 4 can be reduced, seizure and partial wear in the pinion gears 3 and 4 and the differential case 2 can be suppressed, and the pinion gears 3 and 4 and the side gears 5L, A good meshing state with 5R 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 the differential case 2 is formed of one piece of member has been described. However, the present invention is not limited to this, and may be a differential case including a plurality of case elements.

(2) In the present embodiment, the case where two (one pair) pinion gears 3 and 4 meshing with the side gears 5L and 5R are disposed in the differential case 2 has been described, but the present invention is not limited to this, By setting the diameter to a small size, three or more pinion gears can be arranged in the differential case.

The disassembled perspective view shown in order to demonstrate the differential for vehicles which concerns on embodiment of this invention. The longitudinal cross-sectional view shown in order to demonstrate the differential for vehicles which concerns on embodiment of this invention. The cross-sectional view shown in order to demonstrate the differential for vehicles which concerns on embodiment of this invention. Sectional drawing which shows the assembly | attachment state of the pinion gear of the differential for vehicles which concerns on embodiment of this invention. The perspective view which shows the differential case of the differential gear for vehicles which concerns on embodiment of this invention. Sectional drawing shown in order to demonstrate the pinion gear in the differential for vehicles which concerns on embodiment of this invention. (A) And (b) is the front view and bottom view shown in order to demonstrate the one tooth | gear contact state with respect to the differential case of the pinion gear in the vehicle differential gear which concerns on embodiment of this invention. (A) And (b) is the front view and bottom view shown in order to demonstrate the 2 tooth | gear contact state with respect to the differential case of the pinion gear in the differential for vehicles which concerns on embodiment of this invention. The graph which shows the result of having considered the surface pressure reduction effect of the pinion gear (6 teeth) in the vehicle differential gear which concerns on embodiment of this invention. The graph which shows the result which considered the surface pressure reduction effect of the pinion gear (7 teeth) in the differential for vehicles which concerns on embodiment of this invention. The graph which shows the result of having considered the tilt reduction effect of the pinion gear (6 teeth) in the vehicle differential device which concerns on embodiment of this invention. The graph which shows the result of having considered the tilt reduction effect of the pinion gear (7 teeth) in the vehicle differential gear which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vehicle differential device 2 ... Differential case, 2A ... Space part 3, 4 ... Pinion gear, 3A, 4A ... Through-hole, 3B, 4B ... Sliding part,
3a, 4a ... first supported portion, 3b, 4b ... second supported portion, 30, 40 ... proximal end portion, 31, 41 ... gear portion 5L, 5R ... side gear, 5La, 5Ra ... boss portion, 5Lb, 5Rb ... Gear part, 5Lc, 5Rc ... Sliding part 6L, 6R ... Thrust washer, 6La, 6Ra ... Washer body 9L, 9R ... Axle insertion hole, 9Lc, 9Rc ... Thrust washer receiving part 10, 11 ... Pinion gear support part, 10A, 11A ... Pinion gear back hole, 10a, 11a ... 1st pinion gear support surface, 10B, 11B ... Extension part, 10b, 11b ... 2nd pinion gear support surface, 10c, 11c ... Washer receiving part 12L, 12R ... Side gear passage hole 13 ... Ring gear mounting flanges 21, 22 ... Thrust washers 23 ... Axle spacers 26,27 ... Locking pieces m, n ... Pinion gear receiving part C Gear axis G ... central point meshing P ... action line O ... Rotation axis

Claims (6)

A pair of side gears;
A plurality of pinion gears meshed with the pair of side gears with a gear axis orthogonal thereto and having a sliding surface on the outer periphery of the gear;
A differential case having a pinion gear support portion that accommodates the plurality of pinion gears and the pair of side gears and rotatably supports the plurality of pinion gears by sliding with the sliding surface;
The plurality of pinion gears have a gear meshing portion that receives a reaction force accompanying torque transmission to the pair of side gears, and a pressure angle of the gear meshing portion indicates an action line due to the resultant force of the reaction force and the sliding surface. A vehicle differential device that is set to an angle that always intersects the pinion gear support. The plurality of pinion gears include a first sliding surface in which the sliding surface is provided over the entire gear axis, and a first portion provided around the gear axis of the gear meshing portion connected to the first sliding surface. Formed with two sliding surfaces,
The differential case is formed of a first pinion gear support surface that slidably supports the first sliding surface and a second pinion gear support surface that slidably supports the second sliding surface. The vehicle differential device according to claim 1.   In the differential case, the first pinion gear support surface is formed of a circumferential surface provided over the entire gear axis line of the plurality of pinion gears, and the second pinion gear support surface is provided in part of the gear pin line of the plurality of pinion gears. The vehicle differential device according to claim 2, wherein the vehicle differential device is formed of a circular arc surface.   4. The vehicle differential device according to claim 3, wherein the second pinion gear support surface extends toward the rotation axis of the differential case and is connected to the first pinion gear support surface. 5.   The plurality of pinion gears have a gear radial dimension from the meshing center point of the gear meshing portion to the first sliding surface, and a gear front end surface of the gear meshing portion from the meshing center point of the gear meshing portion. The dimension in the gear axial direction to the side endmost side is b, and the dimension in the gear axis direction from the gear front end side endmost part of the first sliding surface to the gear front end side endmost part of the gear meshing portion is c. And when the dimension in the gear axial direction from the gear rear surface endmost portion of the first sliding surface to the gear front end surface side endmost portion of the gear meshing portion is d, the pressure angle α of the gear meshing portion is The vehicle differential device according to claim 2, wherein the vehicle differential is set to an angle satisfying c <b + a × tan α <d.   The vehicle differential device according to claim 1, wherein the plurality of pinion gears are shaftless pinion gears.

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