JPH0764214B2 - 4-wheel drive - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a four-wheel drive system for a vehicle such as an automobile, and more specifically, in a horizontal transaxle type, a four-wheel drive drive mode with direct connection, a four-wheel drive drive mode with a center differential capable of limiting differential, and a rear-wheel drive drive mode The present invention relates to a four-wheel drive device capable of arbitrarily selecting the three types of driving modes.

[Prior art]

Conventionally, regarding a four-wheel drive system, for example, the actual development of Sho 55-7242
There is one with a center differential shown in Japanese Patent No. 0. In this four-wheel drive system with a center differential, a diff lock mechanism is indispensable for exiting from a rough road, and it has been shown that a diff lock mechanism is used to hydraulically lock. Further, as a direct-coupling type four-wheel drive device, for example, the one using a viscous coupling is shown in Japanese Utility Model Publication No. 59-188731.

[Problems to be Solved by the Invention]

By the way, since the above-mentioned prior art can obtain only one of the driving modes of the center differential type and the direct coupling type, it is difficult to satisfy the traveling performance when the road condition is bad. Further, in the former four-wheel drive system with a center differential, there is a problem that the structure is complicated because the differential lock mechanism uses a hydraulic clutch. Therefore, the present invention has three types of running modes with a simple structure, such as a direct-coupled four-wheel drive running mode, a center-differential four-wheel-drive running mode capable of differential limiting, and a rear-wheel drive running mode. An object is to provide a selectable four-wheel drive device.

[Means for Solving the Problems]

As a means for achieving this object, the present invention provides a front diff device that is configured to transmit power from a transfer shaft that is arranged in parallel to a transmission output shaft to a front wheel and a rear drive shaft that is configured to transmit power to rear wheels. A four-wheel drive device for transmitting, a planetary gear device as a center differential device, which is arranged coaxially with the transfer shaft, a carrier is coupled to the transfer shaft, and a ring gear is transmitted to the rear drive shaft, and the transfer device. A hub is connected coaxially to the shaft, a hub is connected to the sun gear of the planetary gear device, and a housing is connected to the ring gear and has a viscous coupling having a differential limiting function, and is rotatably supported coaxially with the transfer shaft. The intermediate shaft, which is configured to be transmitted to the front differential device, and the connecting position corresponding to the lever operation, the first A first mesh clutch having three switching positions of a disengagement position and a second disengagement position for connecting and disconnecting the transfer shaft and the intermediate shaft, and switching to three switching positions in cooperation with the first mesh clutch. When the first mesh clutch is operated and the first mesh clutch is in the connection position, the housing of the viscous coupling is connected to the intermediate shaft, and the first mesh clutch is in the first position.
A second meshing clutch that connects the hub of the viscous coupling and the intermediate shaft when in the disengaged position, and a first meshing clutch that connects the hub of the viscous coupling and the housing when the second meshing position is in the disengaged position. It is characterized by that.

In the present invention employing such means, when the first dog clutch is lever-operated to the connecting position, the transfer shaft and the intermediate shaft are connected, and at the same time, the intermediate shaft is passed through the second dog clutch. And the housing of the viscous coupling are connected. Therefore, in the planetary gear device as the center differential device, the carrier and the ring gear are integrated through the transfer shaft, the intermediate shaft, and the housing of the viscous coupling to be in a diff lock state, and the ring gear is connected to the front differential device through the intermediate shaft. The direct drive four-wheel drive traveling mode is selected in which power is transmitted to the rear drive shaft directly from the ring gear. Further, when the first dog clutch is lever-operated to the first cutoff position, the transfer shaft is disconnected from the intermediate shaft, and at the same time, the hub of the viscous coupling and the intermediate shaft are connected via the second dog clutch. Once connected, the housing of the viscous coupling is disconnected. Therefore, in the planetary gear unit, the ring gear can be differentiated from the sun gear to release the differential lock state, and the planetary gear unit functions as a center differential unit while transmitting power from the sun gear to the front differential unit via the hub and the intermediate shaft. In addition, a four-wheel drive mode with a center differential in which power is directly transmitted from the ring gear to the rear drive shaft is selected. At this time, the differential between the front differential device and the rear drive shaft is limited by a predetermined amount or more in accordance with the differential limiting function of the viscous coupling provided between the sun gear and the ring gear. Further, when the first dog clutch is lever-operated to the second cutoff position, the transfer shaft is disconnected from the intermediate shaft, and at the same time, the hub of the viscous coupling and the housing are connected via the second dog clutch. However, the intermediate shaft is disconnected. Therefore, the intermediate shaft is disconnected from the transfer shaft and the planetary gear device, and in this state, the sun gear and the ring gear are integrated into the diff-lock state in the planetary gear device, and the viscous coupling is also integrated into the planetary gear device. The rear-wheel drive traveling mode in which power is transmitted only from the ring gear of the planetary gear device to the rear drive shaft is selected.

【Example】

An embodiment of the present invention will be specifically described below with reference to the drawings. Referring to the drawings, a transmission system of a four-wheel drive system according to an embodiment based on a transversely mounted transaxle type front engine / front drive (FF) vehicle will be described. Are horizontally arranged in the left-right direction, and the front differential device 4 and the transfer device 5 are sequentially arranged from the transmission 3 to the rear of the vehicle body. And transmission 3, front differential device 4 and transfer device 5
Is installed inside the clutch housing 6, the transmission case 7, and the extension case 8 to form a transaxle type. The transmission 3 is of a constant mesh type and meshes with the input shaft 10 from the clutch 2 and the output shaft 11 arranged in parallel therewith, for example, the first speed to the fifth speed (overdrive).
A pair of speed change gears 12 to 16 are provided.
By selectively operating the synchro mechanism 17 between the gears 13 and 13, the synchro mechanism 18 between the speed change gears 14 and 15, or the synchro mechanism 19 adjacent to the speed change gear 16, the first speed to the fifth speed Each forward gear up to high speed is obtained. Further, the reverse gear 20 integrated with the input shaft 10 is configured to mesh with the gear 21 on the sleeve side of the synchronizing mechanism 17 through an idler gear (not shown) to obtain the reverse gear. The front differential device 4 has a differential device 24 that rotatably supports a gear 23 that meshes with an output gear 22 of the transmission output shaft 11 and that is arranged concentrically with the gear 23. Connected to the left and right front wheels via axle 25. Here, the transfer device 5 has a transfer shaft 27 that is integrally coupled with a transfer gear 26 that meshes with the gear 23 and that is installed in the lateral direction of the vehicle body, and is rotatably supported coaxially with the transfer shaft 27 and has a gear 31. Intermediate shaft that is configured to be transmitted to the differential device 24 of the front differential device 4 via
33, a set of planetary gear devices 40 having a function as a center differential device, a viscous coupling 45 having a differential limiting function, a first dog clutch 50 and a second dog clutch for switching to a plurality of running modes. A clutch 55 is provided. The planetary gear unit 40 includes a sun gear 41, a ring gear 42, a pinion gear 43 that meshes with both gears 41, 42, and a pinion gear.
It is composed of a carrier 44 that supports 43, and is installed coaxially with the transfer shaft 27. And this planetary gear device 40
The carrier 44 is connected to the transfer shaft 27, the ring gear 42 is transmitted to the rear drive shaft 29 via the pair of bevel gears 28, and is further transmitted to the rear wheels via the propeller shaft 30 and the like. The viscous coupling 45 has a hub 46 and a housing 47, and a plate 48, 49 integral with either one between them.
Are alternately arranged and a highly viscous liquid is enclosed. When the rotation difference between the hub 46 and the housing 47 increases, the shearing resistance of the enclosed liquid causes an engagement action to increase the transmission torque. The viscous coupling 45 is installed coaxially with the transfer shaft 27 similarly to the planetary gear unit 40, the hub 46 is integrally coupled to the sun gear 41 of the planetary gear unit 40, and the housing 47 is integrally coupled to the ring gear 42 of the planetary gear unit 40. To be done. The first dog clutch 50 and the second dog clutch 55 are a 4WD with a sensor differential capable of limiting the differential and an F-wheel directly connected to the front and rear wheels.
It is for switching between R directly connected 4WD and FR, and the first dog clutch 5
0 is an F / R direct connection 4WD position as a connection position for connecting the transfer shaft 27 and the intermediate shaft 33, a 4WD position as a first disconnection position for disconnecting the two, and a first connection for disconnecting the two. The sleeve 52 is always meshed with the hub 51 which is integral with the transfer shaft 27 and has three positions, the FR position as the second cutoff position, along the transfer shaft 27. Only at the connecting position is the tooth 52a of the sleeve 52 attached to one spline 33a of the intermediate shaft 33.
, And the meshing is disengaged at the first shutoff position and the second shutoff position. The second dog clutch 55 is a three-position switching lever operated in conjunction with the first dog clutch 50, has a sleeve 56 movable along the transfer shaft 27, and has a longitudinal direction. A first tooth 56a is formed in the middle, a second tooth 56b is formed at the right end, and a third tooth 56c is formed at the left end. When the first dog clutch 50 is in the F / R direct connection 4WD position where the first dog clutch 50 is in the connecting position, the second tooth 56b of the sleeve 56 has the viscous coupling 4 in place.
The housing 47 and the intermediate shaft 33 are connected by meshing with the spline 47a integral with the housing 47 of FIG. 5 and with the third tooth 56c meshing with the other spline 33b of the intermediate shaft 33. Also, the first dog clutch 50 is at the first disengagement position 4W.
In the D position, the second tooth 56b of the sleeve 56 is disengaged from the spline 47a of the housing 47, and the first tooth 56a of the sleeve 56 meshes with one spline 46a integral with the hub 46 of the viscous coupling 45. The third tooth 56c meshes with the other spline 33b of the intermediate shaft 33, thereby connecting the hub 46 of the viscous coupling 45 and the intermediate shaft 33. Further, when the first dog clutch 50 is in the FR position, which is the second disengagement position, the third tooth 56c of the sleeve 56 moves the intermediate shaft 33.
It comes off from the other spline 33b of the
First tooth 56a of the same meshes with the other spline 46b integral with the hub 46 of the viscous coupling 45, and the sleeve 56
The second tooth 56b of the above meshes with the spline 47a of the housing 47, thereby connecting the hub 46 of the viscous coupling 45 and the housing 47. Here, the first dog clutch 50 and the second dog clutch
As an operation system for the 55, a select lever (not shown) is provided in which three positions of 4WD, F / R direct connection 4WD and FR are linearly arranged in the left-right direction along the axial direction of the transfer shaft 27. A rail 35 from the above is engaged with the sleeve 52 of the first dog clutch 50 and the sleeve 56 of the second dog clutch 55, respectively. Next, the operation of the four-wheel drive system of this embodiment constructed as described above will be described. First, the synchro mechanism 17,1 in the transmission 3 when the vehicle is traveling.
The gears for shifting 12 to 16,2 by synchronizing with 8,19 etc.
0, 21 and the like output the transmission output shaft 11 with five forward gears and one reverse gear. The power of the transmission output shaft 11 is input to the transfer shaft 27 via the output gear 22, the gear 23, and the transfer gear 26, and the transfer shaft 27
Input to the carrier 44 of the planetary gear unit 40. Therefore, use the select lever to move the rail 35 to the middle FR
When operated to the direct connection 4WD position, the teeth 52a of the sleeve 52 of the first mesh clutch 50 mesh with one spline 33a of the intermediate shaft 33 as shown in the figure, whereby the transfer shaft 27 and the intermediate shaft 3
3 and connect. At the same time, the second tooth 56b of the sleeve 56 of the second dog clutch 55 meshes with the spline 47a of the housing 47 of the viscous coupling 45, and the third tooth 56c meshes with the other spline 33b of the intermediate shaft 33. The housing 47 of the viscous coupling 45 and the intermediate shaft 33 are connected. Therefore, the planetary gear unit 40 is
The 44 and the ring gear 42 are integrated with each other through the transfer shaft 27, the intermediate shaft 33, and the housing 47 of the viscous coupling 45 to be in a diff-lock state. Therefore, in this case, the power of the transmission output shaft 11 input to the carrier 44 of the planetary gear device 40 in the differential lock state via the transfer shaft 27 is changed from the ring gear 42 of the planetary gear device 40 to the housing 47 of the viscous coupling 45.
It is transmitted to the front wheels via the intermediate shaft 33, the gear 31, the gear 32, the differential device 24 of the front differential device 4, the axle 25, etc., and is transmitted from the ring gear 42 to the pair of bevel gears 28, the rear drive shaft 29, the propeller shaft. It is transmitted to the rear wheels via 30 etc., and thus, the direct-coupling four-wheel drive traveling mode is achieved in which the torque distributions of the front and rear wheels are substantially equal. And in this direct drive four-wheel drive mode,
Maximum starting performance and running performance on rough roads. Then, when the rail 35 is operated to the left 4WD position by the select lever, the first dog clutch 50 moves the left side of the sleeve 52 to move the tooth 52a and one spline 33a of the intermediate shaft 33.
And the transfer shaft 27 and the intermediate shaft 33 are disconnected from each other. At the same time, the second dog clutch 55 is a sleeve.
The second tooth 56b of 56 disengages from the spline 47a of the housing 47 of the viscous coupling 45, and the first tooth 56a of the sleeve 56 meshes with one spline 46a of the hub 46 of the viscous coupling 45 and Tooth 56c is the intermediate shaft
By meshing with the other spline 33b of 33, the hub 46 of the viscous coupling 45 and the intermediate shaft 33 are connected. Therefore, in the planetary gear unit 40, the ring gear 42 is the sun gear.
The differential gear 41 and the differential lock state are released, and the planetary gear device 40 functions as a center differential device. Therefore, in this case, the transmission output shaft 11 input to the carrier 44 of the planetary gear unit 40 via the transfer shaft 27.
Power from the small diameter sun gear 41 to the viscous coupling
It is transmitted to the front wheels via the hub 46 of 45, the intermediate shaft 33, the gear 31, the gear 32, the differential device 24 of the front differential device 4, the axle 25, and the like, and the large-diameter ring gear 42 to the pair of bevel gears 28,
It is transmitted to the rear wheels via the gear drive shaft 29, the propeller shaft 30 and the like, and thus the four-wheel drive mode with a center differential, which emphasizes maneuverability and has a rear wheel torque TR larger than the front wheel torque TF, is set. In the four-wheel drive mode with the center differential, the viscous coupling 45 interposed between the sun gear 41 and the ring gear 42 of the planetary gear unit 40 places the sun gear 41 and the ring gear 42 in accordance with the differential limiting function. The differential above a certain amount is limited, and accordingly, the differential between the differential 24 of the front differential device 4 and the rear drive shaft 29 is limited to a predetermined amount or less. That is, when the vehicle normally turns, the viscous coupling 45 becomes free to allow the difference in rotation between the front and rear wheels, so that smooth turning performance is exhibited, and wheel slip occurs, causing the differential 24 and the rear drive. When the shaft 29 and the differential are more than a predetermined amount, the differential device 24 and the rear drive shaft 2 are engaged by the engagement action of the plates 48 and 49 of the viscous coupling 45.
Since the differential with 9 is limited to a predetermined amount or less, it is possible to automatically escape from a bad road in this way. On the other hand, when the rail 35 is operated to the FR position on the right side by the select lever, the first meshing clutch 50 disengages the tooth 52a from one spline 33a of the intermediate shaft 33 due to the right movement of the sleeve 52, and the transfer shaft moves. The connection between 27 and the intermediate shaft 33 is cut off. At the same time, in the second dog clutch 55, the third tooth 56c of the sleeve 56 is disengaged from the other spline 33b of the intermediate shaft 33, and the first tooth 56a of the sleeve 56 is moved to the other spline 46b of the hub 46 of the viscous coupling 45. Mesh with
In addition, the second tooth 56b of the sleeve 56 meshes with the spline 47a of the housing 47, so that the viscous coupling 4
The hub 46 and the housing 47 of 5 are connected. Therefore, the intermediate shaft 33 is disconnected from the transfer shaft 27 and the planetary gear device 40, and in this state, the planetary gear device 40 is
41 and ring gear 42 are integrated into a diff lock state, and viscous coupling 45 is also a planetary gear device.
Integrate with 40. Therefore, in this case, the power of the transmission output shaft 11 that is input to the carrier 44 of the planetary gear unit 40 in the differential lock state via the transfer shaft 27 is transmitted from the ring gear 42 to the pair of bevel gears 28, the rear drive shaft 29, the propeller shaft 30, etc. The vehicle is in the rear-wheel drive traveling mode in which it is transmitted only to the rear wheels via the. The operation of the select lever may be performed using an actuator such as air pressure or a motor.

【The invention's effect】

As described above, according to the present invention, when the first dog clutch is lever-operated to the connecting position, the planetary gear device as the center differential device is in the diff lock state and the direct connection for transmitting power to the front diff device and the rear drive shaft. When the four-wheel drive traveling mode is selected and the lever device is moved to the first shut-off position, the four-wheel drive traveling mode with the center differential that transmits power to the front differential device and the rear drive shaft while the planetary gear device functions as the center differential device. When the lever is selected and the lever is operated to the second cut-off position, the planetary gear unit is in the differential lock state with the intermediate shaft disconnected from the transfer shaft and the planetary gear unit, and the rear-wheel drive traveling mode in which power is transmitted only to the rear drive shaft. It is selected, and a direct-coupled four-wheel drive running mode that excels in running on rough roads, Turning performance and the center 4-wheel drive mode with differential resulting lubricity, 3 between the rear wheel drive running mode
Any kind of traveling mode can be selected. Then, when the direct-coupled four-wheel drive traveling mode is selected, the torque of the transmission output shaft is distributed from the transfer shaft to the front differential device and the rear drive shaft through the ring gear of the planetary gear device in the differential lock state in a substantially equal manner, and the center differential is selected. When the four-wheel drive with drive mode is selected, the torque of the transmission output shaft is small in the front differential device via the sun gear and ring gear of the planetary gear unit that is in a differential state from the transfer shaft, and it is largely unequal in the rear drive shaft. When the rear-wheel drive drive mode is selected, the torque of the transmission output shaft is transmitted only to the rear drive shaft. It is possible to obtain the distributed traveling performance and the traveling performance in which the torque is transmitted only to the rear wheels. Here, when the four-wheel drive mode with the center differential is selected, the differential between the sun gear and the ring gear of the planetary gear device is limited by a predetermined amount or more in accordance with the differential limiting function of the viscous coupling, and accordingly, the front differential is selected. Since the differential between the device and the rear drive shaft is limited to a predetermined amount or less,
It is possible to escape from a bad road. Also, because a viscous coupling is used for limiting the differential between the front differential device and the rear drive shaft,
The structure is simple.

[Brief description of drawings]

The drawings are skeleton diagrams showing an embodiment of a four-wheel drive system according to the present invention. 3 ... transmission, 4 ... front differential device, 5 ... transfer device, 11 ... transmission output shaft, 26 ... transfer gear, 27 ... transfer shaft, 29 ... rear drive shaft,
40: planetary gear device, 41: sun gear, 42: ring gear, 44: carrier, 45: viscous coupling, 50: first mesh clutch, 55: second mesh clutch.

Claims (1)

[Claims] 1. A four-wheel drive system for appropriately transmitting power to a front differential device configured to transmit from a transfer shaft arranged in parallel to a transmission output shaft to a front wheel and to a rear drive shaft configured to transmit to a rear wheel. And a planetary gear device as a center differential device, which is arranged coaxially with the transfer shaft, a carrier is connected to the transfer shaft, and a ring gear is configured to be transmitted to the rear drive shaft; and a planetary gear device coaxial with the transfer shaft. The hub is connected to the sun gear of the planetary gear device, the housing is connected to the ring gear, and the viscous coupling having a differential limiting function is rotatably supported coaxially with the transfer shaft to be transmitted to the front differential device. The configured intermediate shaft, the connection position according to the lever operation, the first disconnection position, the second disconnection position A first mesh clutch having three switching positions for connecting and disconnecting the transfer shaft and the intermediate shaft, and a switching operation to three switching positions in association with the first mesh clutch, and a first mesh clutch. Is in the connecting position, the housing of the viscous coupling and the intermediate shaft are connected, and when the first meshing clutch is in the first disengagement position, the hub of the viscous coupling and the intermediate shaft are connected to form the first meshing. A four-wheel drive system comprising: a second meshing clutch that connects the hub of the viscous coupling and the housing when the clutch is in the second disengagement position.