JP2018131008A - Rear biaxial drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate switching between an uniaxial drive mode and a biaxial drive mode even during traveling of a vehicle.SOLUTION: A rear biaxial drive device comprises an intermediate differential device 30 capable of distributing driving force to a first shaft 37 and a second shaft 36, a third shaft 14 capable of transmitting driving force from the first shaft 37, a fourth shaft 15 capable of transmitting driving force from the second shaft 36, front-rear differential devices 60 for transmitting the driving force from a third shaft 14 to left and right rear-front driving shafts 18L and 18R, a rear-rear differential device 70 for transmitting the driving force from the fourth shaft 15 to left and right rear-rear driving shafts 19L and 19R, a first joining mechanism 40 capable of selectively joining the first shaft 37 and the second shaft 36, a first synchronizing mechanism 80 for synchronizing the first shaft 37 and the second shaft 36 in rotation, a second joining mechanism 48 capable of selectively joining the second shaft 36 and the fourth shaft 38, and a second synchronizing mechanism 84 for synchronizing the second shaft 36 and the fourth shaft 38 in rotation.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a technique for transmitting a driving force of a power source in a vehicle having a rear front shaft and a rear rear shaft as driving shafts that can be driven by the driving force of the power source.

  2. Description of the Related Art Conventionally, a rear biaxial drive vehicle having two drive shafts (a rear front shaft and a rear rear shaft) on a rear shaft is known as a vehicle such as a truck.

  In such a rear two-shaft drive vehicle, a technique is known in which the driving force of the engine is transmitted only to the rear front shaft, so that transmission loss due to driving of the drive shaft is reduced and fuel efficiency is improved ( For example, see Patent Document 1).

Japanese Patent Laid-Open No. 10-86688

  By the way, in the structure described in Patent Document 1, the shafts are selectively coupled by the shift movement of the sleeves to transmit the driving force only to the rear front shaft, and the driving force is transmitted to the rear front shaft. In addition, it is possible to switch to the “biaxial drive mode” for transmitting to both the rear and rear rear shafts. However, in this structure, when the mode is switched while the vehicle is running, the shafts in which the rotational speed difference is generated are forcibly connected by the sleeve, which causes a gear ringing or breakage of the meshing element, or There is a possibility that mode switching may fail. In addition, in order to avoid such gear squealing and breakage of the meshing elements, there is a problem that it takes a long time to switch the mode if the mode is switched until the rotation speed of each shaft is synchronized.

  An object of the technology of the present disclosure is to provide a rear biaxial drive device that can easily switch between the “uniaxial drive mode” and the “biaxial drive mode” even while the vehicle is traveling.

  The technology of the present disclosure includes a propeller shaft to which a driving force is transmitted from a driving source, and an intermediate differential device that can distribute the driving force from the propeller shaft to the first shaft and the second shaft via an intermediate differential mechanism. A third shaft capable of transmitting a driving force from the first shaft, a fourth shaft capable of transmitting a driving force from the second shaft, and at least a third driving force from the third shaft. A rear front drive gear provided on the shaft, a rear front ring gear meshing with the rear front drive gear, a rear front differential device transmitting to the left and right rear front drive shafts via the rear front differential mechanism, and the fourth shaft From the rear rear drive gear provided on the fourth shaft, the rear rear ring gear meshing with the rear rear drive gear, and the rear rear differential mechanism. After differential A first coupling mechanism capable of selectively coupling the first shaft and the second shaft to lock the intermediate differential mechanism, and the first coupling mechanism and the second shaft by the first coupling mechanism. A first synchronization mechanism that synchronizes rotation of the first and second shafts by generating a synchronous load between the first shaft and the second shaft when the shaft is coupled; and the second shaft; A second coupling mechanism capable of selectively coupling the fourth shaft to connect and disconnect the driving force from the second shaft to the fourth shaft; and the second coupling mechanism and the second shaft. A second synchronization mechanism for generating a synchronous load between the second shaft and the fourth shaft to rotate and synchronize the second and fourth shafts when the four shafts are coupled, By the second coupling mechanism When the two shafts and the fourth shaft are coupled, a biaxial drive is performed in which a driving force is transmitted to the rear front drive shaft and the rear rear drive shaft, and the second shaft and the second shaft by the second coupling mechanism When the coupling with the four shafts is released, uniaxial driving is performed in which the driving force is transmitted only to the rear front driving shaft.

  A third coupling mechanism capable of selectively connecting the first shaft and the third shaft to connect and disconnect the driving force from the first shaft to the third shaft; and A third synchronization mechanism that, when the first shaft and the third shaft are coupled, generates a synchronous load between the first shaft and the third shaft to rotationally synchronize the first and third shafts. The second shaft and the fourth shaft are coupled by the second coupling mechanism, and the coupling between the first shaft and the third shaft by the third coupling mechanism is released. It is preferable that the driving force is transmitted to only the rear rear driving shaft.

  Further, it is preferable that a gear ratio between the rear front drive gear and the rear front ring gear is set to a gear ratio different from a gear ratio between the rear rear drive gear and the rear rear ring gear.

  And a lift axle device that raises the drive shaft to which the driving force is not transmitted among the rear front drive shaft or the rear rear drive shaft and lifts the drive wheels attached to the drive shaft from the road surface. Also good.

  According to the technology of the present disclosure, it is possible to provide a rear biaxial drive device that can easily switch between the “uniaxial drive mode” and the “biaxial drive mode” even while the vehicle is traveling.

1 is a schematic overall configuration diagram showing a vehicle according to a first embodiment of the present invention. It is a mimetic diagram showing the back and front differential device and back and back differential device concerning a first embodiment of the present invention. It is a mimetic diagram showing a back biaxial drive concerning a first embodiment of the present invention. FIG. 4 is a schematic diagram for explaining a “rear and front uniaxial drive mode” according to the first embodiment of the present invention. FIG. 4 is a schematic diagram for explaining a “rear and rear uniaxial drive mode” according to the first embodiment of the present invention. It is a schematic diagram explaining the “normal biaxial drive mode” according to the first embodiment of the present invention. It is a schematic diagram explaining the “diff lock biaxial drive mode” according to the first embodiment of the present invention. It is a schematic diagram which shows the back biaxial drive device which concerns on 2nd embodiment of this invention. It is a schematic diagram which shows the back biaxial drive device which concerns on other embodiment of this invention.

  Hereinafter, based on an accompanying drawing, the back biaxial drive device concerning the embodiment of the present invention is explained. The same parts are denoted by the same reference numerals, and their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[First embodiment]
FIG. 1 is a schematic overall configuration diagram showing a vehicle 1 according to the present embodiment. The vehicle 1 is, for example, a rear biaxial drive vehicle such as a truck. The vehicle 1 is equipped with an engine 10 as an example of a power source. A transmission 12 is connected to the engine 10 via a clutch device 11 so as to be connected and disconnected. An interaxle differential gear device (hereinafter referred to as an intermediate differential device) 30 is connected to the transmission 12 via a propeller shaft 13.

  The intermediate differential device 30 includes a rear front shaft input shaft 14 (an example of a third shaft), a rear front shaft differential gear device (hereinafter referred to as a rear front differential device) 60, left and right rear front drive shafts 18L, R. The left and right rear front drive wheels 20L, R are connected via the. The intermediate differential device 30 includes a rear rear shaft input shaft 15 (an example of a fourth shaft), a rear rear shaft differential gear device (hereinafter, rear rear differential device) 70, and left and right rear rear drive shafts 19L, R. The left and right rear rear drive wheels 21L and R are connected via the. In the drawing, reference numerals 22L and 22 denote left and right front wheels (steering wheels), reference numeral 100 denotes an electronic control unit (hereinafter referred to as ECU), and reference numeral 105 denotes a switch device provided in the cab.

  As shown in FIG. 2, the rear front differential device 60 (an example of the rear front differential device) includes a rear front differential housing 61 in which lubricating oil is sealed, a rear front drive pinion gear 62, a rear front ring gear 63, A front differential case 64, a plurality of (for example, four) rear front differential pinion gears 65, and a pair of left and right rear front side gears 66, 67 are provided.

  The rear front drive pinion gear 62 is provided at the output end of the rear front shaft input shaft 14 so as to be integrally rotatable. The rear front drive pinion gear 62 always meshes with the rear front ring gear 63.

  The rear front ring gear 63 is fixed to the rear front differential case 64 with bolts (not shown). The rear front differential pinion gear 65 is rotatably supported by the rear front spider shaft 68 of the rear front differential case 64. The rear front differential pinion gear 65 always meshes with the left and right rear front side gears 66 and 67. The rear front side gears 66 and 67 are spline fitted to the left and right rear front drive shafts 18L and 18R, respectively.

  The rear front differential case 64, the rear front differential pinion gear 65, the rear front side gears 66, 67, and the rear front spider shaft 68 are differentials that transmit a driving force while allowing a rotational difference between the left and right rear front drive shafts 18L, R. The mechanism is configured.

  The rear rear differential device 70 (an example of a rear rear differential device) includes a rear rear differential housing 71, a rear rear drive pinion gear 72, a rear rear ring gear 73, a rear rear differential case 74, and a plurality of ( For example, four rear rear differential pinion gears 75 and a pair of left and right rear rear side gears 76 and 77 are provided.

  The rear rear drive pinion gear 72 is provided at the output end of the rear rear shaft input shaft 15 so as to be integrally rotatable. The rear rear drive pinion gear 72 always meshes with the rear rear ring gear 73.

  The rear rear ring gear 73 is fixed to the rear rear differential case 74 with bolts (not shown). The rear rear differential pinion gear 75 is rotatably supported on the rear rear spider shaft 78 of the rear rear differential case 74. The rear rear differential pinion gear 75 always meshes with the left and right rear rear side gears 76 and 77. The rear rear side gears 76 and 77 are spline-fitted to the left and right rear rear drive shafts 19L and 19R, respectively.

  The rear rear differential case 74, the rear rear differential pinion gear 75, the rear rear side gears 76, 77, and the rear rear spider shaft 78 are differentials that transmit a driving force while allowing a rotational difference between the left and right rear rear drive shafts 19L, R. The mechanism is configured.

  In the present embodiment, the final gear ratio of the rear front differential device 60 (the gear ratio between the rear front drive pinion gear 62 and the rear front ring gear 63) is set to a small gear ratio (for example, about 4.0) suitable for high speed travel. The final gear ratio of the rear rear differential device 70 (the gear ratio between the rear rear drive pinion gear 72 and the rear rear ring gear 73) is set to a large gear ratio (for example, about 6.0) suitable for low-speed traveling. .

  As shown in FIG. 3, the intermediate differential device 30 (an example of an intermediate differential device) includes an intermediate differential housing (not shown) in which lubricating oil is enclosed, an intermediate differential case 31, and a plurality of (for example, four) intermediate differential pinion gears. 33, an intermediate front differential gear 34, an intermediate rear differential gear 35, a through shaft 36 (an example of a second shaft), an outer shaft 37 (an example of a first shaft), and an intermediate output shaft 38 (an example of a fourth shaft). Drive helical gear 49, driven helical gear 59, first coupling mechanism 40, first synchronization mechanism 80, second coupling mechanism 48, second synchronization mechanism 84, third coupling mechanism 50, and third synchronization. And a mechanism 90.

  A propeller shaft 13 is connected to the intermediate differential case 31 so as to be integrally rotatable. The intermediate differential pinion gear 33 is rotatably supported by the intermediate spider shaft 32 of the intermediate differential case 31.

  The intermediate front differential gear 34 meshes with the intermediate differential pinion gear 33 on the front side. An input end of the through shaft 36 is connected to the intermediate front differential gear 34 so as to be integrally rotatable.

  The intermediate rear differential gear 35 meshes with the intermediate differential pinion gear 33 on the rear side. An input end of an outer shaft 37 inserted through the through shaft 36 is connected to the intermediate rear differential gear 35 so as to be integrally rotatable.

  A differential mechanism that transmits a driving force while allowing a rotational difference between the through shaft 36 and the outer shaft 37 by the intermediate differential case 31, the intermediate spider shaft 32, the intermediate differential pinion gear 33, the intermediate front differential gear 34, and the intermediate rear differential gear 35. Is configured.

  The intermediate output shaft 38 is spaced apart from the rear end side of the through shaft 36. The input end of the rear rear shaft input shaft 15 is connected to the output end of the intermediate output shaft 38 via a universal joint 39.

  The drive helical gear 49 is provided on the output side of the outer differential case 31 of the outer shaft 37 so as to be integrally rotatable by spline fitting or the like. A driven helical gear 59 is always meshed with the driving helical gear 49. The driven helical gear 59 is provided on the input end side of the rear front shaft input shaft 14 through a needle bearing or the like so as to be relatively rotatable.

  The first coupling mechanism 40 includes a first hub 41 provided at the output end of the outer shaft 37 so as to be integrally rotatable by spline fitting, and the output end of the through shaft 36 protruding from the outer shaft 37 by spline fitting. A first sleeve having a second hub 42 which is provided so as to be integrally rotatable and faces the first hub 41, and an inner peripheral tooth which can selectively mesh with the outer peripheral teeth of the first hub 41 and the second hub 42 by shift movement. 44 and a first actuator 46 for shifting the first sleeve 44. In the present embodiment, the first coupling mechanism 40 assumes the state shown in FIG. 3 where the first sleeve 44 meshes only with the first hub 41 as a neutral position, and the first sleeve 44 shifts and moves from the neutral position to the second position. By engaging with the hub 42, the first hub 41 (outer shaft 37) and the second hub 42 (through shaft 36) are coupled.

  The first synchronization mechanism 80 includes a first cone portion 81 projecting from the second hub 42 toward the first hub 41, and a first synchronizer ring 82 disposed between the first hub 41 and the second hub 42. I have. The first cone portion 81 is integrally formed with the second hub 42, and a tapered friction surface that is inclined with respect to the axial direction is provided on the outer peripheral side thereof. On the inner peripheral side of the first synchronizer ring 82, a tapered friction surface is formed that can slide in contact with the friction surface of the first cone portion 81.

  The first synchronization mechanism 80 causes the friction surface of the first synchronizer ring 82 to slidably contact the friction surface of the first cone portion 81 with the shift movement of the first sleeve 44 toward the second hub 42 to generate a synchronous load. Thus, the first hub 41 (outer shaft 37) and the second hub 42 (through shaft 36) are rotationally synchronized. When the state where the first sleeve 44 meshes with only the second hub 42 is set to the neutral position of the first coupling mechanism 40, the first cone portion 81 may be provided on the first hub 41 side.

  The second coupling mechanism 48 is provided at the input end of the intermediate output shaft 38 so as to be integrally rotatable by spline fitting or the like, and is opposed to the second hub 42. A second sleeve 45 having inner peripheral teeth that can selectively mesh with the outer peripheral teeth of the hub 43 and a second actuator 47 for shifting the second sleeve 45 are provided. In the present embodiment, the second coupling mechanism 48 assumes the state shown in FIG. 3 in which the second sleeve 45 meshes only with the third hub 43 as the neutral position, and the second sleeve 45 shifts from the neutral position and moves to the second position. By engaging with the hub 42, the third hub 43 (intermediate output shaft 38) and the second hub 42 (through shaft 36) are coupled.

  The second synchronization mechanism 84 includes a second cone portion 85 protruding from the second hub 42 toward the third hub 43 side, and a second synchronizer ring 86 disposed between the second hub 42 and the third hub 43. I have. The second cone portion 85 is integrally formed with the second hub 42, and a tapered friction surface that is inclined with respect to the axial direction is provided on the outer peripheral side thereof. On the inner peripheral side of the second synchronizer ring 86, a tapered friction surface capable of sliding contact with the friction surface of the second cone portion 85 is formed.

  The second synchronization mechanism 84 causes the friction surface of the second synchronizer ring 86 to slidably contact the friction surface of the second cone portion 85 with the shift movement of the second sleeve 45 toward the second hub 42 to generate a synchronous load. Thus, the third hub 43 (intermediate output shaft 38) and the second hub 42 (through shaft 36) are rotationally synchronized. When the state where the second sleeve 45 meshes only with the second hub 42 is set to the neutral position of the second coupling mechanism 48, the second cone portion 85 may be provided on the third hub 43 side.

  The third coupling mechanism 50 is provided on the input end of the rear front shaft input shaft 14 so as to be integrally rotatable by spline fitting or the like, and is provided on the driven helical gear 59 so as to be integrally rotatable. The third sleeve 53 having a dog gear 52 facing 51, an outer peripheral tooth of the fourth hub 51 and an inner peripheral tooth that can selectively mesh with the dog tooth of the dog gear 52 by shift movement, and the third sleeve 53 are shifted. And a third actuator 54. In the present embodiment, the third coupling mechanism 50 assumes the state shown in FIG. 3 where the third sleeve 53 meshes only with the fourth hub 51 as the neutral position, and the third sleeve 53 shifts from the neutral position to move the dog gear 52. The fourth hub 51 (rear front shaft input shaft 14) and the dog gear 52 (driven helical gear 59) are coupled to each other.

  The third synchronization mechanism 90 includes a third cone portion 91 that protrudes from the dog gear 52 toward the fourth hub 51, and a third synchronizer ring 92 that is disposed between the dog gear 52 and the fourth hub 51. The third cone portion 91 is integrally formed with the dog gear 52, and a tapered friction surface that is inclined with respect to the axial direction is provided on the outer peripheral side thereof. On the inner peripheral side of the third synchronizer ring 92, a tapered friction surface capable of sliding contact with the friction surface of the third cone portion 91 is formed.

  The third synchronization mechanism 90 causes the friction surface of the third synchronizer ring 92 to slidably contact the friction surface of the third cone portion 91 with the shift movement of the third sleeve 53 toward the fourth hub 51 to generate a synchronous load. Thus, the fourth hub 51 (rear front shaft input shaft 14) and the dog gear 52 (driven helical gear 59) are rotationally synchronized.

  In the present embodiment, the intermediate differential device 30 (A) “rear and front uniaxial drive mode” in which the drive force is transmitted only to the rear and front drive shafts 18L and R, and (B) the drive force only to the rear and rear drive shafts 19L and R. (C) Transmitting the driving force to the rear front drive shafts 18L, R and the rear rear drive shafts 19L, R while allowing the differential to the intermediate differential device 30 “Dual lock drive mode” or (D) “Differential lock biaxial drive mode” in which driving force is transmitted to the rear front drive shafts 18L and R and the rear rear drive shafts 19L and R while the intermediate differential device 30 is locked. It can be switched selectively. Details of each mode will be described below.

[Rear front single axis drive mode]
As shown in FIG. 4, when “A: rear front uniaxial drive mode” is turned on in the switch device 105, the ECU 100 places the first sleeve 44 on the first actuator 46 of the first coupling mechanism 40. 41, the second sleeve 45 is moved to the second actuator 47 of the second coupling mechanism 48, either the second hub 42 or the third hub 43. Only the operation signal to shift to the neutral position meshing with only the third hub 43 (only the third hub 43 in the illustrated example), the third sleeve 53 to the third actuator 54 of the third coupling mechanism 50, both the fourth hub 51 and the dog gear 52 An instruction signal for shifting to a coupling position that meshes with is output.

  That is, when the “rear / front uniaxial drive mode” is selected, the outer shaft 37 and the through shaft 36 are coupled by the first coupling mechanism 40, and the driven helical gear 59 and the rear front shaft are coupled by the third coupling mechanism 50. The input shaft 14 is coupled, and further, the coupling between the through shaft 36 and the intermediate output shaft 38 by the second coupling mechanism 48 is released.

  When the propeller shaft 13 rotates in this state, the intermediate front differential gear 34 and the intermediate rear differential gear 35 rotate in the same rotation. When the intermediate rear differential gear 35 rotates, the driving force is applied to the left and right rear front drive shafts 18L, R via the outer shaft 37 → the drive helical gear 49 → the driven helical gear 59 → the rear front shaft input shaft 14 → the rear front differential device 60. Communicated. On the other hand, since the coupling between the through shaft 36 and the intermediate output shaft 38 is released, the driving force is not transmitted to the rear rear differential device 70. That is, the front / rear uniaxial drive is performed in which the driving force is transmitted only to the rear / front drive shafts 18L / R without being transmitted to the rear / rear drive shafts 19L / R.

  In the present embodiment, the final gear ratio of the rear front differential device 60 is set to a small gear ratio that is particularly suitable for high-speed traveling. In other words, when driving at high speed when there is no need for a large driving force, selecting “Rear / Front Single Axis Drive Mode” enables driving at a high gear ratio, effectively improving fuel efficiency. can do.

  At the time of switching to the “rear and front uniaxial drive mode”, the first synchronization mechanism 80 synchronizes the rotation of the first hub 41 (outer shaft 37) and the second hub 42 (through shaft 36) and also performs the third synchronization. The fourth hub 51 (rear front shaft input shaft 14) and the dog gear 52 (driven helical gear 59) are configured to be rotationally synchronized by the mechanism 90. As a result, even when the vehicle is traveling, it is possible to easily switch to the “rear and front uniaxial drive mode” without causing gear ringing or breakage of each meshing element.

[After rear single-axis drive mode]
As shown in FIG. 5, when “B: rear uniaxial drive mode” is turned on in the switch device 105, the ECU 100 places the first sleeve 44 on the first hub 46 in the first actuator 46 of the first coupling mechanism 40. 41 or the second hub 42 (the first hub 41 only in the illustrated example) is shifted to a neutral position to be engaged, and the second sleeve 45 is attached to the second actuator 47 of the second coupling mechanism 48. An operation signal for shifting to a coupling position that meshes with both the second hub 42 and the third hub 43, and a neutral position in which the third sleeve 53 meshes only with the fourth hub 51 in the third actuator 54 of the third coupling mechanism 50. An instruction signal for shifting to is output.

  That is, when the “rear and rear uniaxial drive mode” is selected, the through shaft 36 and the intermediate output shaft 38 are coupled by the second coupling mechanism 48, and the outer shaft 37 and the through shaft 36 are coupled by the first coupling mechanism 40. And the coupling between the driven helical gear 59 and the rear front shaft input shaft 14 by the third coupling mechanism 50 are released.

  When the propeller shaft 13 rotates in this state, the intermediate front differential gear 34 and the intermediate rear differential gear 35 rotate while allowing a differential. When the intermediate front differential gear 34 rotates, the driving force is transmitted to the left and right rear rear drive shafts 19L, R via the through shaft 36 → the intermediate output shaft 38 → the rear rear shaft input shaft 15 → the rear rear differential device 70. . On the other hand, since the coupling between the driven helical gear 59 and the rear front shaft input shaft 14 is released, the driving force is not transmitted to the rear front differential mechanism 60. That is, the rear rear single-axis drive is performed in which the driving force is transmitted only to the rear rear drive shafts 19L, R without being transmitted to the rear front drive shafts 18L, R.

  In the present embodiment, the final gear ratio of the rear rear differential device 70 is set to a large gear ratio that is particularly suitable for low-speed traveling. In other words, when starting in a loaded state that requires a large driving force, when starting on a slope, or when traveling at a very low speed, select the “rear and rear single-axis drive mode” to run at a low gear ratio. Thus, it is possible to effectively obtain the driving force necessary for starting the vehicle 1 and traveling at a low speed.

  In addition, when switching to the “rear and rear single-axis drive mode”, the second synchronization mechanism 84 is configured so that the third hub 43 (intermediate output shaft 38) and the second hub 42 (through shaft 36) are rotationally synchronized. ing. As a result, even when the vehicle is running, it is possible to easily switch to the “rear-rear single-axis drive mode” without causing a gear ringing or breakage of each meshing element.

[Normal two-axis drive mode]
As shown in FIG. 6, when “C: normal biaxial drive mode” is turned on in the switch device 105, the ECU 100 places the first sleeve 44 on the first actuator 46 of the first coupling mechanism 40. 41 or the second hub 42 (the first hub 41 only in the illustrated example) is shifted to a neutral position to be engaged, and the second sleeve 45 is attached to the second actuator 47 of the second coupling mechanism 48. An operation signal for shifting to a coupling position that meshes with both the 2 hub 42 and the third hub 43, and a third sleeve 53 for the third actuator 54 of the third coupling mechanism 50 and both the fourth hub 51 and the dog gear 52. An instruction signal for shifting to a coupling position that meshes with is output.

  That is, when the “normal two-axis drive mode” is selected, the through shaft 36 and the intermediate output shaft 38 are coupled by the second coupling mechanism 48, and the driven helical gear 59 and the rear front shaft are coupled by the third coupling mechanism 50. The input shaft 14 is coupled, and further, the coupling between the outer shaft 37 and the through shaft 36 by the first coupling mechanism 40 is released.

  When the propeller shaft 13 rotates in this state, the intermediate front differential gear 34 and the intermediate rear differential gear 35 rotate while allowing a differential. When the intermediate rear differential gear 35 rotates, the driving force is applied to the left and right rear front drive shafts 18L, R via the outer shaft 37 → the drive helical gear 49 → the driven helical gear 59 → the rear front shaft input shaft 14 → the rear front differential device 60. Communicated. On the other hand, when the intermediate front differential gear 34 rotates, the driving force is transmitted to the left and right rear rear drive shafts 19L, R via the through shaft 36 → the intermediate output shaft 38 → the rear rear shaft input shaft 15 → the rear rear differential device 70. Is done. In other words, in a state where the differential between the intermediate front differential gear 34 and the intermediate rear differential gear 35 by the intermediate differential device 30 is allowed, the driving force is transmitted to both the rear front drive shafts 18L, R and the rear rear drive shafts 19L, R. It becomes a biaxial drive.

  In the present embodiment, the final gear ratio of the rear front differential device 60 is set to a small gear ratio (for example, 4.0), and the final gear gear ratio of the rear rear differential device 70 is set to a large gear ratio (for example, 6.0). Is set to That is, by selecting the “normal two-axis drive mode” at the time of stacking travel that requires driving force, the intermediate differential device 30 is allowed to have a differential, and the final gear ratio of the vehicle 1 is set to the rear front differential device 60 and the rear differential device 60. It becomes possible to travel with the average value (= (4.0 + 6.0) /2=5.0) of each final gear ratio of the rear differential device 70, and the fuel efficiency can be improved effectively.

  At the time of switching to the “normal two-axis drive mode”, the third hub 43 (intermediate output shaft 38) and the second hub 42 (through shaft 36) are rotationally synchronized by the second synchronization mechanism 84, and the third The fourth hub 51 (rear front shaft input shaft 14) and the dog gear 52 (driven helical gear 59) are rotationally synchronized by the synchronization mechanism 90. As a result, even when the vehicle is running, it is possible to easily switch to the “normal two-axis drive mode” without causing gear ringing or breakage of each meshing element.

[Differential lock biaxial drive mode]
As shown in FIG. 7, when “D: differential lock biaxial drive mode” is turned ON in the switch device 105, the ECU 100 places the first sleeve 44 on the first hub 46 in the first actuator 46 of the first coupling mechanism 40. 41, the second sleeve 45 is moved to the second hub 42 and the third hub 43 to the second actuator 47 of the second coupling mechanism 48. An operation signal for shifting to the coupling position for meshing, and an instruction signal for shifting the third sleeve 53 to the coupling position for meshing with both the fourth hub 51 and the dog gear 52 by the third actuator 54 of the third coupling mechanism 50. Output.

  That is, when the “differential lock biaxial drive mode” is selected, the outer shaft 37 and the through shaft 36 are coupled by the first coupling mechanism 40, and the through shaft 36 and the intermediate output shaft 38 are coupled by the second coupling mechanism 48. Further, the driven helical gear 59 and the rear front shaft input shaft 14 are coupled by the third coupling mechanism 50.

  In this state, when the propeller shaft 13 rotates, the intermediate front differential gear 34 and the intermediate rear differential gear 35 rotate so as to have the same rotation. When the intermediate rear differential gear 35 rotates, the driving force is applied to the left and right rear front drive shafts 18L, R via the outer shaft 37 → the drive helical gear 49 → the driven helical gear 59 → the rear front shaft input shaft 14 → the rear front differential device 60. Communicated. On the other hand, when the intermediate front differential gear 34 rotates, the driving force is transmitted to the left and right rear rear drive shafts 19L, R via the through shaft 36 → the intermediate output shaft 38 → the rear rear shaft input shaft 15 → the rear rear differential device 70. Is done.

  That is, in the state in which the intermediate differential device 30 is differentially locked, the driving force is biaxially transmitted to both the rear front drive shafts 18L, R and the rear rear drive shafts 19L, R. As a result, even if one of the rear front drive shafts 18L, R or the rear rear drive shafts 19L, R is idle, the other drive shaft is kept rotating. It is possible to escape.

  At the time of switching to the “differential lock biaxial drive mode”, the first synchronization mechanism 80 synchronizes the rotation of the first hub 41 (outer shaft 37) and the second hub 42 (through shaft 36) and also performs the second synchronization. The third hub 43 (intermediate output shaft 38) and the second hub 42 (through shaft 36) are rotationally synchronized by the mechanism 84, and the fourth hub 51 (rear front shaft input shaft 14) is further synchronized by the third synchronization mechanism 90. And the dog gear 52 (driven helical gear 59) are configured to be rotationally synchronized. As a result, even when the vehicle is running, it is possible to easily switch to the “diff lock two-axis drive mode” without causing gear ringing or breakage of each meshing element.

  As described above in detail, according to the present embodiment, the final gear ratio of the rear front differential device 60 is set to a small gear ratio suitable for high speed traveling, and the final gear ratio of the rear rear differential device 70 is low speed traveling. It is set to a large gear ratio suitable for. In addition, the intermediate differential device 30 is connected to each of the coupling mechanisms 40, 48, and 50 in the “rear and front uniaxial drive mode”, “rear and rear uniaxial drive mode”, “normal biaxial drive mode”, or “diff lock biaxial drive mode”. A total of four modes can be selectively switched.

  In other words, when driving at high speed when there is no need for a large driving force, selecting “Rear / Front Single Axis Drive Mode” enables driving at a high gear ratio, effectively improving fuel efficiency. can do. In addition, when starting in a loaded state that requires a large driving force, when starting on a slope, or when traveling at a very low speed, select the “rear and rear single-axis drive mode” to drive at a low gear ratio. Thus, it is possible to effectively obtain the driving force necessary for starting the vehicle 1 and traveling at a low speed. Further, by selecting the “normal two-axis drive mode” during loading travel that requires driving force, the intermediate differential device 30 is allowed to have a differential, and the final gear ratio of the vehicle 1 is set to the rear front differential device 60 and the rear differential device 60. It becomes possible to travel with the average value of each final gear ratio of the rear differential device 70, and the fuel efficiency can be effectively improved. In addition, the final transmission ratio of the vehicle 1 can be changed without adding a gear train or a sub-transmission to the transmission 12, and the transmission 12 can be effectively reduced in size and weight.

  Further, when switching to each mode, the meshing elements 41, 42, 43, 51, 52 to be coupled by the coupling mechanisms 40, 48, 50 are rotationally synchronized by the synchronization mechanisms 80, 84, 90. It is configured. As a result, even when the vehicle is running, it is possible to easily switch between modes without causing a gear ringing or breakage of each meshing element.

[Second Embodiment]
FIG. 8 is a schematic diagram showing a rear biaxial drive device according to the second embodiment. The rear biaxial drive device of the second embodiment is obtained by adding lift axle devices 200F and R including air springs 210F and R to the first embodiment.

  More specifically, as shown in FIG. 8, when “A: rear front uniaxial drive mode” is selected in the switch device 105, the air is discharged from the air spring 210R of the lift axle device 200R, and the rear The rear drive shafts 19L, R are lifted upward, and the rear rear drive wheels are lifted from the road surface. On the other hand, when “B: rear rear single shaft drive mode” is selected, although not shown, air is discharged from the air spring 210F of the lift axle device 200F and the rear front drive shafts 18L and 18R are lifted upward. The rear front drive wheel is lifted off the road surface.

  In this way, the driving wheels that are in the non-driven state are lifted from the road surface by the lift axle devices 200F, 200R, so that the rolling resistance and the mechanical friction of the differential devices 60, 70 can be effectively reduced. Thus, the fuel efficiency can be further improved.

[Others]
In addition, this invention is not limited to the above-mentioned embodiment, In the range which does not deviate from the meaning of this invention, it can change suitably and can implement.

  For example, in each of the above-described embodiments, the final gear ratio of the rear front differential device 60 has been described as being set smaller than the final gear ratio of the rear rear differential device 70. Alternatively, these final gear ratios may be set to the same value.

  Further, as shown in FIG. 9, a driven helical gear 59 is provided on the rear front shaft input shaft 14 so as to be integrally rotatable, and the third coupling mechanism 50 and the third synchronization mechanism 90 are omitted. , “Normal two-axis drive mode” and “Diflock two-axis drive mode” may be selectively switched to a total of three modes. In this configuration, when a high speed gear ratio is required in the “rear and front single shaft drive mode”, the final gear ratio of the rear and rear differential device 60 is set smaller than the final gear ratio of the rear and rear differential device 70, When a low gear ratio is required in the “single-axis drive mode”, the final gear ratio of the rear front differential device 60 may be set larger than the final gear ratio of the rear rear differential device 70.

  In addition, the synchronization mechanisms 80, 84, 90 have been described as generating a synchronous load by sliding contact between the friction surfaces of the taper portions 81, 85, 91 and the friction surfaces of the synchronizer rings 82, 86, 92. These mechanisms may be eliminated, and each meshing element may be configured to be rotationally synchronized using a braking force acting on the rear front drive wheels 20L, R and / or the rear rear drive wheels 21L, R.

  Further, the vehicle 1 is not limited to a truck, and can be widely applied to vehicles other than a truck as long as it is a rear two-axis drive vehicle.

DESCRIPTION OF SYMBOLS 1 Vehicle 10 Engine 11 Clutch apparatus 12 Transmission 13 Propeller shaft 14 Rear front shaft input shaft 15 Rear rear shaft input shaft 18L, R Rear front drive shaft 19L, R Rear rear drive shaft 30 Intermediate differential device 36 Through shaft 37 Outer Shaft 40 First coupling mechanism 48 Second coupling mechanism 50 Third coupling mechanism 60 Rear front differential device 62 Rear front drive pinion gear 63 Rear front ring gear 70 Rear rear differential device 72 Rear rear drive pinion gear 73 Rear rear ring gear 80 First synchronization mechanism 81 1st cone part 82 1st synchronizer ring 84 2nd synchronization mechanism 85 2nd cone part 86 2nd synchronizer ring 90 3rd synchronization mechanism 91 3rd cone part 92 3rd synchronizer ring

Claims (4)

A propeller shaft to which a driving force is transmitted from a driving source;
An intermediate differential device capable of distributing the driving force from the propeller shaft to the first shaft and the second shaft via an intermediate differential mechanism;
A third shaft capable of transmitting a driving force from the first shaft;
A fourth shaft capable of transmitting a driving force from the second shaft;
Driving power from the third shaft at least through the rear front drive gear provided on the third shaft, the rear front ring gear meshing with the rear front drive gear, and the left and right rear front drive A rear differential that transmits to the shaft, and
Driving force from the fourth shaft is at least a rear rear drive gear provided on the fourth shaft, a rear rear ring gear meshing with the rear rear drive gear, and left and right rear rear drives via a rear rear differential mechanism. After-differential transmission to the shaft,
A first coupling mechanism capable of selectively coupling the first shaft and the second shaft to lock the intermediate differential mechanism;
When the first shaft and the second shaft are coupled by the first coupling mechanism, a synchronous load is generated between the first shaft and the second shaft so that the first and second shafts are A first synchronization mechanism for synchronizing rotation;
A second coupling mechanism capable of selectively coupling the second shaft and the fourth shaft to connect and disconnect the driving force from the second shaft to the fourth shaft;
When the second shaft and the fourth shaft are coupled by the second coupling mechanism, a synchronous load is generated between the second shaft and the fourth shaft so that the second and fourth shafts are A second synchronization mechanism that synchronizes the rotation,
When the second shaft and the fourth shaft are coupled by the second coupling mechanism, it becomes a biaxial drive in which a driving force is transmitted to the rear front drive shaft and the rear rear drive shaft,
Rear biaxial drive characterized in that, when the coupling between the second shaft and the fourth shaft by the second coupling mechanism is released, the driving force is transmitted to only the rear front driving shaft. apparatus. A third coupling mechanism capable of selectively coupling the first shaft and the third shaft to connect and disconnect the driving force from the first shaft to the third shaft;
When the first shaft and the third shaft are coupled by the third coupling mechanism, a synchronous load is generated between the first shaft and the third shaft so that the first and third shafts are A third synchronization mechanism that synchronizes the rotation;
When the second shaft and the fourth shaft are coupled by the second coupling mechanism, and the coupling between the first shaft and the third shaft by the third coupling mechanism is released, only the rear rear drive shaft is provided. The rear biaxial drive device according to claim 1, wherein the drive force is transmitted to the single axis drive. The rear biaxial drive according to claim 1 or 2, wherein a gear ratio between the rear front drive gear and the rear front ring gear is set to a gear ratio different from a gear ratio between the rear rear drive gear and the rear rear ring gear. apparatus. 2. A lift axle device that raises a drive shaft, to which drive force is not transmitted, out of the rear front drive shaft or the rear rear drive shaft and lifts drive wheels attached to the drive shaft from a road surface. The rear biaxial drive device as described in any one of 3 to 3.

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