JPS6313823A - Four-wheel drive device - Google Patents

Abstract

PURPOSE:To make it possible to select various drive conditions, by connecting a transmission member to an input member or to the first rotation member incorporated to the input member through the first clutch, and furnishing the third clutch between the second rotation member connected to and transmitted with the said connection through the second clutch and an output member of a differential device. CONSTITUTION:The first clutch C1 is furnished between a transmission member 14 and a differential 3, and the second clutch C2 is furnished between the transmission member 14 and the hub 17 of a viscous cup ring 13. Moreover, the hub 17 and a side gear 10 of the differential 3 are connected through the third clutch C3. In such a composition, the connecting relations among the differential 3, the viscous cup ring 13, and the transmission member 14 varies depending on the gearing and the releasing conditions of the first to the third clutches C1, C2, and C3, and various kinds of driving conditions can be set. Therefore, an optimum driving condition can be obtained responding to the diverse road conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to a four-wheel drive system having a transfer including a viscous coupling.

Prior art The present applicant has developed this type of four-wheel drive device in Japanese Patent Application Laid-Open No. 1986-23.
It was already proposed in No. 6839. To explain the outline of this device, the driving force from the transmission is transmitted to the input member of the first differential mechanism, that is, the case of the center differential, and one side gear of the center differential is transmitted to the case of the front wheel differential, for example. The center differential is connected to the case, and the other side gear is connected to the rear export force shaft via a shaft and a gear, and the case of the center differential and the other side gear are connected by a viscous coupling. The viscous coupling transmits driving force between the first plate and the second plate by shearing resistance of a fluid such as silicone oil. Therefore, the rotational speed is increased between the case of the center differential and the other side gear. If there is no difference between A transmission occurs, which acts as a differential limiter for the center differential. In other words, it is possible to tolerate a certain degree of difference in rotational speed between the front and rear wheels, thereby preventing tight corner braking, and even if one of the front and rear wheels is spinning, the other It can provide sufficient driving force to the wheels and improve traversing performance.

Problems to be Solved by the Invention With the above-mentioned conventional device, sufficient driving force can be transmitted to both the front and rear wheels by limiting the differential operation of the center differential. Since a differential is installed in the front wheels, if one of the front wheels and one of the rear wheels slip due to derailment, etc., the driving force will be transmitted to both the front and rear wheels. The driving force is wasted as the wheels spin. In other words, although the viscous coupling in the conventional device described above acts as a differential limiting device for the center differential, there is no differential limiting device for the front and rear wheels, so if one of the front and rear wheels spins, Even with four-wheel drive, there were frequent problems where the vehicle could not be driven.

In order to eliminate this inconvenience, it is conceivable to attach a differential limiting device to each differential for both front and rear transport, but this would not only complicate the configuration but also reduce the weight of the vehicle. A problem arises in that the amount increases.

This invention was made against the background of the above-mentioned circumstances, and it is possible to select a variety of drive states based on the configuration of the four-wheel vehicle. The object of the present invention is to provide a driving device.

Means for Solving the Problems In order to achieve the above object, the present invention provides a differential v1 that connects an output member to each of the left and right axles on the front wheel side or the rear wheel side to provide a differential to each axle. and a viscous coupling in which a first rotating member is connected and integrated with an input member of the differential mechanism, and a driving force is transmitted between the first rotating member and the second rotating member by the viscosity of fluid. In the four-wheel drive device, a transmission member is connected to the input member or the first rotating member integrated therewith via a first clutch, and the transmission member is connected to the second rotation member via a second clutch. The present invention is characterized in that a third clutch is connected to the rotating member and further provided between the second rotating member and one output member of the differential mechanism.

In the device of the invention, the transmission member can be used as a means for input from the transmission or as a means for output to the front axle or rear axle, but in either case the first Depending on the engagement/disengagement state of the third clutch, the connection relationship between the differential mechanism, the viscous coupling, and the transmission member changes, and various driving states are set. In other words, when the first clutch is connected, the input member of the differential mechanism and the transmission member are integrated, so the rotation of the input member is transmitted to the front or rear axle via the transmission member, resulting in four-wheel drive. Alternatively, driving force is transmitted from the input member to the front or rear axle via the differential mechanism, resulting in four-wheel drive.

Furthermore, if only the second clutch is connected, the transmission member is integrated with the second rotating member of the viscous coupling, so the input to the differential mechanism is transmitted to the front or rear wheels via the viscous coupling. Alternatively, it is input to the differential mechanism via a viscous coupling, and therefore allows differential movement between the front and rear wheels within a certain range, and restricts differential movement beyond that, resulting in so-called automatic four-wheel drive. Furthermore, when the first and second clutches are released, including when only the third clutch is connected, the transmission member is cut off from the differential mechanism and the viscous coupling, resulting in two-wheel drive. If both the first clutch and the third clutch are connected, the input member of the differential mechanism and one output member will be connected via the viscous coupling in the four-wheel drive state, so the differential The action of the groove is limited,
Therefore, the driving force is transmitted almost equally to both the left and right vehicle widths of the front wheel side or the rear wheel side.

Example Next, embodiments of the invention will be described.

FIG. 1 is a schematic diagram showing an example in which the four-wheel drive system of the present invention is applied to a vehicle equipped with a horizontal engine. (hereinafter referred to as a front wheel differential) 3, and is further transmitted via a transfer 4 to the other differential 5 (hereinafter referred to as a rear wheel differential). In other words, the case 6, which is the input member of the front wheel differential 3, has
A ring gear 8 meshing with the output gear 7 of the transmission 2 is attached, and each side gear 9, 10 of this front wheel differential 3 is connected to a front axle 11, 12.

The transfer 4 includes a viscous coupling 13, a transmission member 14, and first to third clutches CI.

The viscous coupling 13 consists of a plurality of plates 16 attached to a cylindrical case 15 as a first rotating member, and a hub as a second rotating member. A large number of plates 1 are attached to 17 so as to face each other with the plate 16 in between.
8 and a viscous fluid such as silicone oil filled inside the case 15, and torque is transmitted between each plate 16, 18 by the shear resistance of the fluid. A case 15 of this viscous coupling 13 is connected and integrated with the case 6 of the front wheel differential 3.

The transmission member 14 is for transmitting driving force to the rear export force shaft 19 via a pair of gears 20, and is provided coaxially with the viscous coupling 13. A first clutch C1 is provided between the case 6 of the front wheel differential 3 or the case 15 of the viscous coupling 13 to connect and disconnect the two.

Also, the hub 1 of the transmission member 14 and the viscous coupling 13
7 is provided with a second clutch C2 that connects and disconnects these. Further, the third clutch C3, which is a component of the transfer 4, is configured to connect and disconnect the hub 17 of the viscous coupling 13 and one side gear 10 of the front wheel differential 3.

The rear export force shaft 19 is the rear wheel differential 5.
The propeller shaft 21 is connected to the propeller shaft 21.

Next, the operation of the above device will be explained.

The above device connects the first to third clutches C1°C2, C
The transmission progress of the driving force changes depending on the engagement/release state of clutches CI and C2, and various drive states are set, and each clutch CI, C2
, C3, the relationship between the engaged/released state and the driving state is as shown in Table 1. Note that in the @1 table, the O mark indicates engagement, (○) indicates that either engagement or release is acceptable, and no mark indicates release.

Table 1 Each mode will be explained below.

(mode ■) This is a state in which only the second clutch C2 is engaged.

Therefore, in this case, since the hub 17 of the viscous coupling 13 and the transmission member 14 are connected and integrated, the driving force transmitted from the transmission 2 to the case 6 of the front wheel differential 3 is transmitted to each side gear 9.10. It is transmitted to the front axle 11, 12 via the viscous coupling 13, to the transmission member 14, and further transmitted to the rear wheel differential 5 via the rear export force shaft 19 and the propeller shaft 21. That is, since the driving force is transmitted to the rear export power shaft 19 via the viscous coupling 13, differential movement between the front wheels 22 and the rear wheels 23 is allowed only within a certain range, and therefore tight corner braking is possible. In addition, it is possible to prevent a situation where one wheel spins and the driving force is not transmitted to the other wheel.
D).

(Mode ■) A state in which only the first clutch C1 is engaged or a state in which the first and second clutches CI and C2 are engaged. Therefore, in this case, the front wheels to which driving force is transmitted from the transmission 2 Case 6 of differential 3 and transmission member 1
4 are connected and integrated, so the front wheel 22 and the rear wheel 23
The driving force is transmitted to both the front wheels 22 and the rear wheels 23, resulting in four-wheel drive (4WD>). The distribution ratio of each horn is fixed at 50%, so no differential occurs, and as a result, although tight corner braking occurs, breaking performance is improved.

Therefore, when only the first clutch C1 is engaged and released, the first clutch C1 functions similarly to a clutch for switching between two-wheel drive and four-wheel drive in a part-time four-wheel drive system.

[Mode ■]

This is a state in which the first clutch C1 and the third clutch C3 are engaged, and the second clutch C2 is released. In this case, the first clutch C1 is engaged, resulting in four-wheel drive (4WD>), and in addition, the third clutch C3 is engaged, so the case 6 of the front wheel differential 3 and one side The side gear 10 is connected via a viscous coupling 13, and as a result, the differential operation of the front wheel differential 3 is limited. That is, the viscous coupling 13 acts as a differential limiting device for the front wheel differential 3, Therefore, since the driving force is always transmitted to the left and right front wheels, even if one of the front and rear wheels spins due to wheel derailment or the like, the vehicle can run and escape from such a situation.

[Mode IV] This is a state in which all of the first to third clutches CI, C2, and C3 are engaged. In this case, the case 6 of the front wheel differential 3 to which driving force is transmitted from the transmission 2 and the transmission member 14 are connected and integrated by the first clutch C1, and the first clutch C1 is engaged. Viscous coupling 13 integrated with transmission member 14
The case 15 and its hub 17 are connected and integrated by the second clutch C2, and the first and second clutch C
By engaging I and C2, the case 6 of the front wheel differential 3 and one of the side gears 10 are connected and integrated by the third clutch C3. That is, since the case 6 of the front wheel differential 3, the side gear 10 on one side, and the transmission member 14 are integrated, there is no difference between the front wheels 22 and the rear wheels 23 and the left and right front wheels 22. Four-wheel drive (4WD>), which also regulates
The ability to traverse rough roads is extremely high.

[Mode V]

This is a state in which only the third clutch C3 is engaged.

In this case, the transmission member 14 is the viscous coupling 13
Since the driving force is not transmitted to the rear export power shaft 19, the drive becomes two-wheel drive (2WD). Also, since the third clutch C3 is engaged, the case in the front wheel differential 3 6 and one side gear 10 are connected via the viscous coupling 13, and as a result, the viscous coupling 13 acts as a differential limiting device for the front wheel differential 3, and only one of the front wheels 22 is connected. In this driving state, although the performance on rough roads is inferior, it is possible to achieve an economical driving state with less power loss.

[Mode I This is a state in which all of the first to third clutches CI, C2, and C3 are released. In this case, since the case 15 and hub 17 of the viscous coupling 13 are not connected to other members, the drive horn is not transmitted to the rear export force shaft 19, and the differential operation of the front wheel differential 3 is limited. Therefore, it is a normal two-wheel drive (2WD). In this case as well, an economical operating state can be achieved as in the above-mentioned mode V.

Next, another embodiment of the invention will be described with reference to FIG.

The example shown here is an example in which the device of the present invention is applied to a vehicle equipped with a vertical engine. It is marked with a symbol. That is, the transmission 2 has a rear export power shaft 19 and a front export power shaft 24, and then the export power shaft 19 is connected to the rear wheel differential 5 via the propeller shaft 21, and the front export power shaft 24 is connected to the rear wheel differential 5 via the propeller shaft 21. is connected to the transmission member 14 via a propeller shaft 25 and a pair of gears 20. The other structure is basically the same as the structure shown in FIG. A first clutch C1 for connecting and disconnecting these is provided between the hub 17 of the viscous coupling 13 and the transmission member 14.
A second clutch C2 that connects and disconnects these is provided between the two. Furthermore, a third clutch C3 is provided that connects and disconnects one side gear 10 of the front wheel differential 3 and the hub 17 of the viscous coupling 13.

In the configuration shown in FIG. 2, the driving force is constantly transmitted to the rear wheels, and the transmission member 14 serves as an input member for the front wheels, so that at least one of the first clutch C1 and the second clutch C2 By engaging one of them, it becomes four-wheel drive. Therefore, the setting of the driving state by engaging and disengaging each of the clutches CI, C2, and C3 is almost the same as in the above-described embodiment, and is shown in Table 2.

Note that also in Table 2, ○ marks indicate engagement, and no marks indicate release.

Table 2 The numbers for each mode in Table 2 correspond to the mode numbers in Table 1, and the respective driving states are also the same as in the embodiment described above. However, in the configuration shown in FIG. This configuration differs from the configuration shown in Figure 1 in that the driving force is input.
Each mode in Table 2 will be briefly explained.

[Mode]

In this state, only the second clutch C2 is engaged, and in this case, from the transmission member 14 to the viscous coupling 13
Since the driving force is transmitted to the hub 17 of the front wheel, the viscous coupling 13 is interposed in the transmission path of the driving force to the front wheel differential 3. Therefore, the viscous coupling 13 keeps the differential between the front and rear wheels constant. Automatic four-wheel drive (automatic 4WD) is permitted within a limited range.

[Mode ■]

A state where only the first clutch C1 is engaged or a state where the first and second clutches CI and C2 are engaged, and in this case, the transmission member 14 and the case 6 of the front wheel differential 3 are mechanically connected. Four-wheel drive (4W) directly connected to
become D).

[Mode■]

This is a state in which the first clutch C1 and the third clutch C3 are engaged, and in this case, in addition to the state of mode (2), the differential operation of the front wheel differential 3 is limited by the viscous coupling 13, and the It is possible to prevent only one wheel of the vehicle from spinning or becoming unable to run due to sagging.

(Mode IV) All of the first to third clutches CI, C2, and C3 must be engaged, and in this case, the front wheel differential 3 and transfer 4 are entirely integrated, so It is four-wheel drive (4WD) with no differential not only in the front wheels 22 but also in the front and rear wheels 22,23.

(Mode VI) The first to third clutches CI, C2 and 03 are all released, and the mode becomes normal two-wheel drive (2WD>).

Note that at the bottom of the groove shown in FIG. 2, the state of mode V in Table 1 is avoided;
, if C2 is released, it becomes two-wheel drive and the left and right front wheels 22 can rotate freely.If the differential of the front wheel differential 3 is limited in this state, neither of the left and right front wheels 22 will rotate during cornering. This is because slipping occurs and the running performance deteriorates.

Further, in the above embodiments, the substantial connection relationship between the respective members has been described, and it goes without saying that in practical use, the connection may be achieved by interposing a suitable member such as a shaft.

Effects of the Invention As is clear from the above explanation, according to the device of the present invention, not only can switching between two-wheel drive and four-wheel drive be performed using a transfer including a viscous coupling, but also the viscous coupling can be used to switch between front and rear wheels. It can be used as a differential limiting device, or as a differential limiting device for left and right wheels.
I can do that. Furthermore, since the viscous coupling fulfills the dual functions of a conventional center differential and a differential limiting device, the entire groove bottom can be made lighter and smaller.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing one example of the device of the present invention, and FIG. 2 is a schematic diagram showing another example of the device of the present invention. 3...Differential, 4...Transfer,
6...Case, 9,1o...Side gear, 11
゜12...Front axle, 13...Viscous coupling, 14...Transmission member, 15...
Case, 17...Hub.

Claims (1)

[Scope of Claims] A differential mechanism that connects an output member to each of left and right axles on a front wheel side or a rear wheel side to provide a differential to each axle, and a first rotating member as an input member of the differential mechanism. A four-wheel drive device comprising a viscous coupling that is connected and integrated and transmits driving force between the first rotating member and the second rotating member by the viscosity of fluid, wherein the input member or the second rotating member is integrated with the input member. A transmission member is connected to the first rotating member which has been converted into a rotary member via a first clutch, the transmission member is connected to the second rotating member via a second clutch, and the second rotating member and the differential mechanism are connected to each other via a second clutch. A four-wheel drive device, characterized in that a third clutch is provided between the output member and one output member of the four-wheel drive device.