JP6260737B2 - Final drive device - Google Patents

Description

  The present invention relates to a final drive device for a vehicle incorporating a differential mechanism.

  At the end of the vehicle drive system, the rotation of the propeller shaft is transmitted to the left and right drive wheels via a final gear and a differential mechanism.

  JP2012-530222A issued by the Japan Patent Office in 2012 proposes a final drive device having a differential mechanism composed of a pair of side gears arranged opposite to each other and a pinion arranged between the pair of side gears. doing. Each pinion is rotatably held by a pinion carrier. The pinion carrier is driven to rotate by a final gear. In this final drive device, the pair of side gears is constituted by a helical face gear, and the pinion is constituted by a helical gear.

  In contrast, JP2008-095744A issued in 2008 by the Japan Patent Office has a side gear constituted by a face gear having a planar pitch surface, and a pinion made by a spur gear, so that the axial direction of the final drive device can be reduced. Propose to reduce the dimensions.

  In such a final drive device, the lubricating oil is supplied to the differential mechanism by immersing a part of the pinion carrier in the lubricating oil in the housing. When the pinion carrier rotates, the lubricating oil is taken into the pinion carrier through the opening formed in the pinion carrier, and lubricates between the side gear and the pinion. It is advantageous that the differential mechanism has a larger number of pinions in consideration of torque transmission performance. On the other hand, it is difficult to increase the number of pinions because it is necessary to form an opening for entering and exiting the lubricating oil.

  JP61-191549A, issued by the Japan Patent Office in 1986, filled the pinion carrier with lubricating oil in a non-contact state with air to prevent oxidation of the lubricating oil in the pinion carrier, and stored the accumulator in the pinion carrier. It is proposed to absorb the volume fluctuation due to the temperature of the lubricating oil. In this case, since the opening for entering and exiting the lubricating oil is not formed in the pinion carrier, the number of pinions can be increased.

  However, it is technically difficult to completely remove air from the pinion carrier. For this reason, it is difficult to completely prevent the lubricating oil in the pinion carrier from contacting with the air. On the other hand, since the lubricating oil does not enter and exit the pinion carrier, the metal powder generated by the meshing of the gear is not discharged from the pinion carrier, but accumulates in the pinion carrier, which causes deterioration of the lubricating oil.

  Accordingly, an object of the present invention is to provide a compact final drive device that can maintain a good lubricating environment even if the number of pinions is increased.

  To achieve the above object, the present invention comprises a final drive gear mechanism comprising a drive pinion and a ring gear that mesh with each other, a differential mechanism that distributes the rotation of the ring gear to the left and right drive wheels, and a final drive gear mechanism and a differential mechanism. The present invention is applied to a final drive device of a vehicle including a housing that stores a lubricating oil.

  The differential mechanism includes a pair of opposing side gears coupled to the left and right drive wheels, a pinion that meshes with the pair of side gears between the pair of side gears, a pinion mate shaft that supports the pinion, and a ring gear that supports the pinion mate shaft. A cylindrical pinion carrier that rotates integrally with the pinion, and a wave washer that is interposed between the pinion and the pinion carrier and supports the pinion on the pinion carrier while being deformed by the meshing force of the pinion and the side gear. .

  Further, a passage between the lubricating oil stored in the housing and the lubricating oil inside the pinion carrier is formed through a gap that the wave washer deflects between the pinion and the pinion carrier.

  The details of the invention as well as other features and advantages are set forth in the following description of the specification and illustrated in the accompanying drawings.

FIG. 1 is a longitudinal sectional view of a final drive apparatus according to a first embodiment of the present invention. FIG. 2 is a longitudinal sectional view of a differential mechanism according to the first embodiment of the present invention. FIG. FIG. 3A is a schematic longitudinal sectional view of the main part of the differential mechanism, showing a state in which the pinion mate shaft is supported on the pinion carrier via the wave washer during vehicle travel according to the first embodiment of the present invention. FIG. 3B is FIG. Although it is similar to 3A, the state at the time of a vehicle stop is shown. FIG. 4A is a schematic longitudinal sectional view of a main part of a differential mechanism showing a support state of a pinion to a pinion carrier via a wave washer during traveling of the vehicle according to a second embodiment of the present invention. FIG. FIG. 4B is FIG. Although it is similar to 4A, the state at the time of a vehicle stop is shown.

  A first embodiment of the present invention will be described.

  FIG. Referring to FIG. 1, a final drive device 1 for a vehicle includes a final drive gear mechanism 4, a differential mechanism 5, and a housing 6 that stores lubricating oil. The final drive gear mechanism 4 includes a drive pinion 2 and a ring gear 3 that mesh with each other. The drive pinion 2 is coupled to the propeller shaft and is driven to rotate by the power of the vehicle. The differential mechanism 5 serves to distribute the rotational torque transmitted from the drive pinion 2 to the ring gear 3 to the left and right drive wheels of the vehicle. The final drive gear mechanism 4 and the differential mechanism 5 are housed in a housing 6 fixed to the vehicle body. The horizontal direction in the figure corresponds to the vehicle transverse direction, and the vertical direction in the figure corresponds to the vertical direction of the vehicle.

  FIG. 2, the differential mechanism 5 includes a pair of opposed side gears 7A and 7B coupled to the left and right drive wheels, and a plurality of pinions 8 meshing with the pair of side gears 7A and 7B between the pair of side gears 7A and 7B. , A pinion mate shaft 9 that supports the pinion 8, and a pinion carrier 10 that supports the pinion mate shaft 9 and rotates integrally with the ring gear 3.

  The pinion carrier 10 includes a cylindrical portion 10A having a diameter in the vehicle longitudinal direction and a block 10B formed at the center of the cylindrical portion 10A. The cylindrical portion 10 </ b> A is fixed to the ring gear 3.

  The pinion 8 is freely fitted to the outer periphery of the pinion mate shaft 9.

  The pinion mate shaft 9 includes a proximal end portion 9A, a flange portion 9B having an enlarged diameter, and a distal end portion 9C having a smaller diameter than the proximal end portion 9A. The base end 9 </ b> A is fitted into a recess formed in the block 10 </ b> B of the pinion carrier 10. The distal end portion 9 </ b> C is fitted into a fitting hole 10 </ b> D formed in the cylindrical portion 10 </ b> A of the pinion carrier 10. The pinion mate shaft 9 is supported by the pinion carrier 10 while being slightly displaceable in the axial direction, that is, in the radial direction with respect to the pinion carrier 10, while being prevented from rotating by the pinion carrier 10. Such a support structure of the pinion mate shaft 9 is such that the distal end portion 9C of the pinion mate shaft 9 is fitted into the fitting hole 10D with different diameters, and the base end portion 9A of the pinion mate shaft 9 is fitted into the recesses of the block 10B with different diameters. This can be realized by a method of combining them, or by providing an engaging means such as a key and a key hole between the pinion mate shaft 9 and the pinion carrier 10. In this embodiment, the four pinion mate shafts 9 are supported by the pinion carrier 10 at intervals of 90 degrees in this way.

  A wave washer 12 is interposed between the flange portion 9B and the inner peripheral surface of the cylindrical portion 10A of the pinion carrier 10.

  A cylindrical holder 10 </ b> C that protrudes toward the center of the pinion carrier 10 relative to the pinion mate shaft 9 is formed on the inner peripheral surface of the cylindrical portion 10 </ b> A of the pinion carrier 10. The flange portion 9B and the wave washer 12 of the pinion mate shaft 9 are accommodated inside the holder 10C.

  The pair of side gears 7 </ b> A and 7 </ b> B have a conical shape with an extremely loose pitch surface and correspondingly, the pinion 8 also has a conical shape whose diameter is slightly increased toward the cylindrical portion 10 </ b> A of the pinion carrier 10. Note that the side gears 7A and 7B may be formed of face gears having a flat pitch surface, and the pitch surface of the pinion 8 may be a cylindrical shape with a uniform diameter. The inclination of the pitch surface is determined so that the stress generated in the wave washer 12 by the meshing force in the radial direction is within the allowable stress range of the wave washer 12.

  One end face of the pinion carrier 10 in the axial direction is closed by the side gear 7 </ b> A and the ring gear 3. The other end surface in the axial direction of the pinion carrier 10 is closed by a side gear 7B and a fixing member 6A fixed to the housing 6. As a result, the space inside the pinion galley 10 in which the pinion 8 is accommodated is outside only through the fitting gap between the fitting hole 10D formed in the cylindrical portion 10A and the tip portion 9C of the pinion mate shaft 9. It communicates with the space in the housing 6.

  Again FIG. 1, the differential mechanism 5 configured as described above is housed in the housing 6 together with the final drive gear mechanism 4. The amount of lubricating oil stored in the housing 6 is such that at least one wave washer 12 is immersed in the lubricating oil while the vehicle is stopped.

  While the vehicle is running, the rotational torque of the propeller shaft is distributed to the pair of side gears 7A and 7B via the drive pinion 2, the ring gear 3, the pinion carrier 10, and the pinion 8 of the final drive device 1, and the left and right drive wheels are driven to rotate. To do. When the resistances of the left and right drive wheels are equal, the pinion 8 does not rotate, but rotates integrally with the pinion carrier 10 and the pair of side gears 7A and 7B, so that the rotational torque is equally distributed to the left and right drive wheels. When the rotational resistance of one drive wheel increases, the pinion 8 rotates, thereby increasing the distribution torque to the side gear 7A (7B) coupled to the drive wheel having a small rotational resistance and coupling to the drive wheel having a large rotational resistance. The distribution torque to the side gear 7B (7A) is reduced.

  In either case, as long as the drive wheels continue to rotate, torque is transmitted from the pinion 8 to the pair of side gears 7A and 7B, and the pinion 8 is engaged with the pinion carrier by the meshing force between the pinion 8 and the side gears 7A and 7B. It is urged toward 10 cylindrical portions 10A. This urging force acts on the flange portion 9B of the pinion mate shaft 9, and the pinion mate shaft 9 is displaced outward in the radial direction of the pinion carrier 10 so as to crush the wave washer 12.

  FIG. The effect brought about by the wave washer 12 will be described with reference to 3A and 3B.

  FIG. Referring to 3A, during rotation of the drive wheels, the pinion mate shaft 9 is urged downward in the drawing by the meshing force between the pinion 8 and the side gears 7A and 7B. Therefore, the wave washer 12 interposed between the flange portion 9B of the pinion mate shaft 9 and the inner peripheral surface of the cylindrical portion 10A of the pinion carrier 10 is flatly crushed and is in close contact with the inner peripheral surface of the cylindrical portion 10A. Become. In this state, as shown in the figure, the fitting gap between the fitting hole 10D of the cylindrical portion 10A and the tip portion 9C of the pinion mate shaft 9 is closed by the wave washer 12 that is in close contact with the inner peripheral surface of the cylindrical portion 10A. .

  FIG. Referring to 3B, when the vehicle is stopped, the rotational torque is not transmitted from the pinion 8 to the pair of side gears 7A, 7B, and no gear meshing component force acts on the pinion 8. In this state, the wave washer 12 regains the original waveform shape and forms a gap between the flange portion 9B and the inner peripheral surface of the cylindrical portion 10A. FIG. The fitting clearance between the fitting hole 10 </ b> D located at the lowest side of 1 and the tip end portion 9 </ b> C is immersed in the lubricating oil stored in the housing 6. Therefore, the lubricating oil is FIG. As indicated by the arrow 3B, the fitting gap between the tip 9C of the pinion mate shaft 9 and the fitting hole 10D and the gap between the flange 9B formed by the wave washer 12 and the inner peripheral surface of the cylindrical part 10A are interposed. Thus, the lubricating oil in the pinion carrier 10 and the lubricating oil stored in the housing 6 circulate with each other.

  With the above structure, the wave washer 12 is in close contact with the inner peripheral surface of the cylindrical portion 10A while the vehicle is running, and the lubricating oil in the pinion carrier 10 is confined inside the pinion carrier 10 and the pinion 8 and the side gear 7A. , 7B is lubricated.

  On the other hand, when the vehicle is stopped, the lubricating oil flows between the inside and the outside of the pinion carrier 10 through the gap between the flange portion 9B formed by the wave washer 12 and the inner peripheral surface of the cylindrical portion 10A. In this way, each time the vehicle stops, the lubricating oil in the pinion carrier 10 is replaced little by little with the lubricating oil stored in the housing 6.

  Therefore, even if metal wear powder is generated due to the engagement of the pinion 8 and the side gears 7A and 7B, the wear powder is gradually discharged to the outside of the pinion carrier 10 as the lubricating oil is stopped. As a result, it is possible to prevent wear powder from accumulating inside the pinion carrier 10. The wear powder that has flowed into the housing 6 is adsorbed by a magnet attached to a drain plug for discharging the lubricating oil from the housing 6. The lubricating oil stored in the housing 6 can be exchanged through the drain plug.

  As described above, the final drive device 1 supplies the lubricating oil via the fitting gap between the fitting hole 10D and the tip portion 9C and the gap that the bending of the wave washer 12 brings between the pinion 8 and the pinion carrier 10. By making it distribute | circulate, the preferable lubrication performance of the differential mechanism 5 can be maintained, without forming the opening part for exclusive use for the distribution | circulation of lubricating oil. Therefore, the differential mechanism 5 can be configured compactly while using the four pinions 8. Further, since the pair of side gears 7A and 7B have a pitch surface close to a plane, the thickness of the gear can be reduced.

  Therefore, according to this embodiment, it is possible to maintain the preferable torque distribution performance and lubrication performance by the four pinions 8 while keeping the size of the final drive device 1 in the vehicle transverse direction small.

  In this embodiment, the gap provided between the pinion 8 and the pinion carrier 10 by the bending of the wave washer 12 is configured between the flange portion 9B of the pinion mate shaft 9 and the cylindrical portion 10A of the pinion carrier 10 that do not rotate. As a result, the rotating pinion 8 does not come into contact with the wave washer 12, and wear of the wave washer 12 can be suppressed.

  FIG. A second embodiment of the present invention will be described with reference to 4A and 4B.

  In this embodiment, the pinion 8 is integrally rotated with the pinion mate shaft 9, while the pinion mate shaft 9 is rotatably supported by the pinion carrier 10. Specifically, the rotation preventing means as in the first embodiment is not provided between the pinion mate shaft 9 and the pinion carrier 10, and both the base end portion 9A and the tip end portion 9C of the pinion mate shaft 9 are formed in a circular cross section. Then, they are respectively fitted freely into the recesses of the block 10B formed in a circular cross section and the fitting holes 10D of the cylindrical portion 10A so as to freely rotate.

  On the other hand, the pinion 8 is fixed to the pinion mate shaft 9. It is also possible to previously form the pinion 8 and the pinion mate shaft 9 integrally.

  The pinion mate shaft 9 is not provided with a flange portion as in the first embodiment, and the proximal end portion 9A and the distal end portion 9C have the same diameter. The wave washer 12 is interposed between the tip end surface of the pinion 8, in other words, the end surface facing the cylindrical portion 10 </ b> A of the pinion carrier 10, and the inner peripheral surface of the cylindrical portion 10 </ b> A of the pinion carrier 10. Other configurations are the same as those of the first embodiment.

  Also in this embodiment, the pinion 8 is urged toward the cylindrical portion 10 </ b> A of the pinion carrier 10 by the meshing force of the pinion 8 and the side gears 7 </ b> A and 7 </ b> B during the rotational driving of the drive wheels. The wave washer 12 is flatly crushed between the tip surface of the pinion 8 and the inner peripheral surface of the cylindrical portion 10A of the pinion carrier 10, and is in close contact with the inner peripheral surface of the cylindrical portion 10A. As a result, FIG. As shown in 4A, the flow of the lubricating oil through the fitting gap between the fitting hole 10D of the cylindrical portion 10A and the tip portion 9C of the pinion mate shaft 9 is blocked by the wave washer 12. The lubricating oil in the pinion carrier 10 lubricates the meshing portion between the pinion 8 and the side gears 7A and 7B in a state of being confined inside the pinion carrier 10.

  On the other hand, when the vehicle is stopped, the fitting gap between the fitting hole 10D and the tip portion 9C, and the gap between the tip surface of the pinion 8 formed by the wave washer 12 returned to the original shape and the inner peripheral surface of the cylindrical portion 10A, The lubricating oil circulates between the inside and outside of the pinion carrier 10. That is, every time the vehicle stops, the lubricating oil in the pinion carrier 10 is replaced little by little with the lubricating oil stored in the housing 6.

  In this way, the pinion 8 is fixed to the pinion mate shaft 9, the pinion mate shaft 9 is rotatably supported by the pinion carrier 10, and the tip end surface of the pinion 8 and the inner peripheral surface of the cylindrical portion 10 </ b> A of the pinion carrier 10 are Even when the wave washer 12 is sandwiched, a preferable effect similar to that of the first embodiment can be obtained.

  Further, in this embodiment, it is not necessary to provide the flange portion 9B on the pinion mate shaft 9, and it is not necessary to provide a means for preventing rotation between the pinion mate shaft 9 and the pinion carrier 10. Therefore, the structure of the differential mechanism 5 can be further simplified.

  In the first embodiment described above, the wave washer 12 is interposed in the gap between the flange portion 9B of the pinion mate shaft 9 and the cylindrical portion 10A of the pinion carrier 10. This gap corresponds to the gap that the bending of the wave washer 12 brings between the pinion 8 and the pinion carrier 10. In the second embodiment, the wave washer 12 is interposed in the gap between the tip surface of the pinion mate shaft 9 and the cylindrical portion 10 </ b> A of the pinion carrier 10. This gap corresponds to the gap that the bending of the wave washer 12 brings between the pinion 8 and the pinion carrier 10. In any of the embodiments, the gap provided between the pinion 8 and the pinion carrier 10 by the bending of the wave washer 12 is still used as a passage for the lubricating oil.

  Although the present invention has been described through several specific embodiments, the present invention is not limited to the above embodiments. Those skilled in the art can make various modifications or changes to these embodiments within the scope of the claims.

Claims (4)

A final drive gear mechanism comprising a drive pinion and a ring gear meshing with each other;
A differential mechanism that distributes the rotation of the ring gear to the left and right drive wheels;
A housing that stores a final drive gear mechanism and a differential mechanism, and that stores a lubricating oil;
The differential mechanism is:
A pair of opposing side gears respectively coupled to the left and right drive wheels;
A pinion meshing with the pair of side gears between the pair of side gears;
A pinion mate shaft with a pinion;
A cylindrical pinion carrier that supports the pinion mate shaft and rotates integrally with the ring gear;
In a vehicle final drive device comprising:
The pinion mate shaft can be displaced in the radial direction with respect to the pinion carrier,
The final drive device further includes a wave washer that is interposed between the pinion mate shaft and the pinion carrier, and supports the pinion mate shaft on the pinion carrier while being deformed by the meshing force of the pinion and the side gear.
A final drive device, characterized in that a passage between the lubricating oil stored in the housing and the lubricating oil inside the pinion carrier is formed through a gap that the wave washer deflects between the pinion and the pinion carrier.   2. The final drive according to claim 1, wherein the wave washer is sandwiched between a pinion mate shaft and a pinion carrier, the pinion mate shaft is supported by the pinion carrier in a state where rotation is restricted, and the pinion is rotatably supported by the pinion mate shaft. apparatus.   The final drive device according to claim 1, wherein the wave washer is sandwiched between the pinion and the pinion carrier, the pinion mate shaft is rotatably supported by the pinion carrier, and the pinion is fixed to the pinion mate shaft.   The pinion mate shaft is fitted into a fitting hole formed in the pinion carrier, and the passage is further formed through a fitting gap between the pinion mate shaft and the fitting hole, and the engagement component force between the pinion and the side gear is used. The final drive device according to any one of claims 1 to 3, wherein the deformed wave washer is configured to close the fitting gap.

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