JPS63291731A - Four-wheel-driving device - Google Patents

Abstract

PURPOSE:To make it possible to easily change over each mode of normal, lock and free for center diff. according to its sliding position by providing, freely in sliding toward a shaft, a differential limitting device which provides the specified bonding power to between separate output shafts on the front wheel side and the rear wheel side of the center diff. CONSTITUTION:The rotational output of an engine 11 is transmitted to a front wheel 16 through a front diff. 23 and to a rear wheel 29 through a rear diff. 28, after being input into a center diff. 14 through a clutch 12 and a speed change gear 13. And a viscous multiple disc clutch 30 constituted of an inner ring part 30a and an outer ring part 30b is provided as a differential limitting device which provides the specified bonding power to between separate output shafts 21, 22 on the front wheel side and the rear wheel side of the center diff. 14. In this case, for a clutch 30, the inner ring part 30 is engaged freely in sliding toward the shaft center to the output shaft 21 on the front wheel side. And separate splines 31, 32, 33, which are formed respectively at the outer ring part 30b and separate output shafts 22, 21 on the front wheel side and the rear wheel side, are made possible to engage/disengage with the slide of the clutch 30.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a four-wheel drive system for an automobile.

(Prior Art and its Problems) A four-wheel drive system that uses a center differential is well known as a four-wheel drive system that distributes and transmits power input from a transmission to front and rear wheels. In this four-wheel drive system, the differential function of the center differential absorbs the rotational difference that occurs between the front wheels, which have a large turning radius, and the rear wheels, which have a small turning radius, when the vehicle is turning. I try to prevent it from being interfered with.

By the way, in the case of a four-wheel drive system that uses a center differential that has the function of absorbing the rotational difference between the front and rear wheels, for example, when the front wheel comes off the wheel, the torque input from the transmission to the center differential is transferred to the rear wheel. The problem arises that the information is not transmitted and it becomes impossible to escape.

Therefore, in order to avoid such a situation, a differential limiting device has been developed that applies a predetermined coupling force between the front wheel output shaft and the rear wheel output shaft of the center differential. FIG. 6 shows a sectional view of essential parts of a conventional example of this type of four-wheel drive device.

In this device, a front wheel side output shaft 1 and a rear wheel side output shaft 2 of a center differential (not shown) are respectively arranged concentrically with a left drive shaft 3 of the front wheels, and an inner wheel portion 4a and an inner wheel portion 4a serve as the differential limiting device. A viscous multi-disc clutch 4 consisting of an outer ring portion 4b has an inner ring portion 4a connected to the front wheel side output shaft 1, and an outer ring portion 4
b are connected to the rear wheel side output shaft 2, respectively. The differential function of the center differential, which attempts to absorb the rotational difference between the front and rear wheels, that is, the rotational difference between the front output shaft 1 and the rear output shaft 2, is limited by the intervention of the viscous multi-disc clutch 4. The aforementioned inability to escape when the wheels come off is avoided.

However, in the conventional configuration described above, the center differential is always subject to differential differential restriction, and the difference in rotation between the front and rear wheels when parking or cornering cannot be sufficiently absorbed, resulting in tight corner braking phenomena. have a problem

(Object of the Invention) This invention was made to solve the above problem, and the differential ability of the center differential that absorbs the rotation difference between the front and rear wheels can be freely switched according to the situation. The purpose is to provide equipment.

(Means for Achieving the Object) This invention provides a center differential that distributes and transmits power input from a transmission to the front and rear wheels, and a predetermined position between the front and rear output shafts of the center differential. and a differential limiting device that limits the differential movement of the center differential by giving a coupling force of 4.
In order to achieve the above object, the wheel drive device is configured such that the differential limiting device is set at a position where differential limiting is applied to the center differential and a position where differential limiting is released relative to the center differential. The front wheel output shaft and the rear wheel output shaft of the center differential are provided so as to be able to be switched to a position where they are directly connected through a part of the motion limiting device, and the differential capacity of the center differential can be changed to a position where the front wheel side output shaft and the rear wheel side output shaft are directly connected. It is configured so that it can be freely switched between a mode in which the differential is limited, a mode in which the differential is completely removed, and a mode in which the front and rear wheels are directly connected.

(Embodiment) Fig. 1 shows an overall mechanical diagram of a vehicle to which a four-wheel drive device according to an embodiment of the present invention is applied, and Fig. 2 is a longitudinal sectional view of the main parts of the four-wheel drive device. shows.

In Figure 1, the engine 11 is placed horizontally at the front.
The rotational output is transmitted from the input shaft 13a of the transmission 1113 via the clutch 12 to the output shaft 13b,
The signal is transmitted to the ring gear 15, which is the input gear of the. The ring gear 15 of the center differential 14 is rotatably supported around the left drive shaft 17a of the front wheel 16, and revolves around the left drive shaft 17a integrally with the ring gear 15. In addition, a binion 18 that is rotatable is provided. Also center differential 1
4 has two side gears 19, 20, one of the side gears 19 is fixed to a cylindrical front wheel side output shaft 21 that fits externally on the left drive shaft 17a, and while meshing with the binion 18, the left side gear 19 is connected to the left drive shaft 17a. It is configured to be rotatable around the axis. The other side gear 20 is fixed to a cylindrical contact-wheel-side output shaft 22 that fits over the front-wheel-side output shaft 21, and is rotatable around the left drive shaft 17a while similarly meshing with the binion 18. It is composed of The rotation of the front wheel side output shaft 21 is transmitted to the left drive shaft 17a and the right drive shaft 17b via the front differential 23, and this rotation is transmitted to the left and right front wheels 16. The rotational difference of width 16 is absorbed by the front differential 23. On the other hand, the rotation of the rear wheel side output shaft 22 is transmitted from the gear 24 fixed to the output shaft 22 to the rear differential 28 via gears 25, 26, 27, and further via the rear differential 28 to the left and right rear wheels 29.
This difference in rotation between the left and right rear wheels 29 is absorbed by the rear differential 28.

Further, as a differential limiting device that provides a predetermined coupling force between the front wheel side output shaft 21 and the rear wheel side output shaft 22 of the center differential 14, a viscous multi-plate clutch 30 consisting of a combination of an inner ring portion 30a and an outer ring portion 30b is used. is provided. That is, the viscous multi-disc clutch 30 has an inner ring portion 3 as shown in FIG.
0a is spline-fitted to the front wheel side output shaft 21 so that it can freely slide in the axial direction, while the spline 31 formed at one end of the outer ring portion 30b is fitted with a spline as the viscous multi-disc clutch 30 slides. , a spline 32 formed at one end of the rear wheel side output shaft 22 facing the spline 31, and a spline fixed to the bamboo wheel side output shaft 21 at a position adjacent to the spline 32 near the viscous multi-disc clutch 3o. The viscous multi-disc clutch 30 is provided so as to be able to engage and disengage from the wheel 33. An operating lever 34 is engaged with the viscous multi-disc clutch 30, and the viscous multi-disc clutch 30 can be slid and operated from the outside by this operating lever 34. In other words, the operating lever 34
As shown in FIG. 2, the rotating shaft 35 of
An eccentric cam 37 protruding from the end surface of the rotating shaft 35 is engaged with a groove 38 provided on the outer peripheral surface of the opposing viscous multi-disc clutch outer ring portion 30b. According to the displacement of the eccentric cam 37 with the rotation of the operating lever 34, the viscous multi-disc clutch 30 engages the front wheel side output shaft 21.
It is designed to slide along its axis.

The operating lever 34 is linked to an operating section on the driver's seat of the vehicle, for example, via a transmission mechanism (not shown).

Next, the operation of this device will be explained. 1, when power is transmitted from the output shaft 13b side of the transmission 13 to the ring gear 15 of the center differential 14, the ring gear 15
The rotation of the pinion 18 that revolves together with the side gear 19
, 20 to the front wheel output shaft 21 and the rear wheel output shaft 22, respectively. The rotation of the front wheel side output shaft 21 is transmitted to the left and right front wheels 16 via the front differential 23, while the rotation of the rear wheel side output shaft 22 is transmitted to the left and right front wheels 16 via the front differential 23.
．． 26.27, is transmitted to the left and right rear wheels 29 via the rear differential 28. At this time, the operating lever 34 is set to the state shown in FIG. 1 in which the viscous multi-disc clutch 30 is positioned at a sliding position where the splines 31 of the viscous multi-disc clutch 30 engage only with the splines 32 of the rear wheel output shaft 22. That is, when the operating lever 34 is in the rotation position shown by the solid line in FIG. The two are connected via the viscous multi-disc clutch 30. That is, the normal mode is set in which the rotation of the binion 18 of the center differential 14 that attempts to absorb the rotation difference between the front wheels 16 and the rear wheels 29 is restricted by the viscous multi-disc clutch 30.

Further, from the above normal mode, as shown in the mechanism diagram in FIG. When the setting of the operating lever 34 is changed to a state where the clutch 30 is positioned, that is, the operating lever 34 is at the rotational position shown by the imaginary line in FIG. 5 (a position displaced by 90 degrees from the previous normal rotational position). When the eccentric cam 37 is displaced to the intermediate position, the front output shaft 21 and the rear output shaft 22 are directly connected via the splines 31 of the viscous multi-disc clutch 30 and the spline wheel 33. That is, the front wheel 16 and the rear wheel 29 are directly connected, and the center differential lock mode is established in which the differential function of the center differential 14 does not work at all.

Furthermore, from the center differential lock mode described above, the viscous multi-disc clutch 30 is moved to a sliding position where the splines 31 of the viscous multi-disc clutch 30 are completely separated from the splines 32 of the rear wheel side output shaft 22, as shown in the mechanism diagram in FIG. When the setting of the operating lever 34 is changed to a position for positioning the
In other words, if the operating lever 34 is at a position 90 degrees displaced from the rotation position of the center differential lock, which is the rotation position indicated by the imaginary line in FIG. 5, and the eccentric cam 37 is biased to the right side in the figure, The front wheel side output shaft 21 and the rear wheel side output shaft 22 are not connected by the viscous multi-plate clutch 30.

That is, a center differential free mode is established in which the difference in rotation between the front wheels 16 and the two rear wheels is completely absorbed by the rotation of the binions 18 of the center differential 14.

Therefore, during normal driving, if the control lever 34 is set to the normal mode and the function of the viscous multi-disc clutch 30 that limits the differential movement of the center differential 14 is activated, it will be easier to escape even if the wheels come off. At the same time, the tight corner braking phenomenon during cornering can be alleviated. Then, only when approaching a rough road that requires treading power, the operator can switch and set the operating lever 34 to the center differential lock mode, thereby making it possible to overcome the rough road without difficulty. On the other hand, when it is necessary to sufficiently absorb the difference in rotation between the front wheels 16 and rear wheels 29, such as when parking in a garage, by switching and setting the operating lever 34 to the center differential free mode, the center differential 14 can absorb viscous The multi-disc clutch 30 is disengaged and the differential function of the center differential 14 is fully utilized, allowing tight corners and
Smooth operation can be performed without causing braking phenomena.

In addition, in this embodiment, the center differential 14 can be adjusted by switching and setting the operation lever 34 according to the driving situation.
a normal mode in which the differential limiting function of the viscous multi-disc clutch 30 operates, a center differential lock mode in which the front and rear wheels are directly connected, and a center differential free mode in which the viscous multi-disc clutch 30 is disconnected from the center differential 14. In the above description, the configuration is such that the operation lever 34 can be freely selected, but the present invention is not limited thereto. Of course, it is also possible to easily select and set modes in response to changes in production plans.

(Effects of the Invention) As described above, according to the four-wheel drive system of the present invention, there is a normal mode in which the differential limiting device operates on the center differential, a center differential lock mode in which the front and rear wheels are directly connected, and a center differential lock mode in which the front and rear wheels are directly connected. You can easily select and set the center differential free mode, where the differential limiting device is separated from the differential, depending on the driving situation, so even if the vehicle falls off the wheels in the normal mode, it is possible to escape. In addition, while the center differential lock mode can be used to overcome rough roads, selecting the center differential free mode allows smooth driving without tight corner braking even when parking the vehicle. Can be done. Moreover, since switching between these modes can be performed using one operating system, effects such as smooth switching operations can be obtained.

[Brief explanation of drawings]

Fig. 1 is a mechanical diagram of a vehicle to which a four-wheel drive device is applied, which is an embodiment of the present invention, Fig. 2 is a vertical sectional view showing the main parts of the four-wheel drive device, and Figs. 3 and 4. are respectively part 4
FIG. 5 is a front view of the operating lever, and FIG. 6 is a longitudinal sectional view showing the main parts of a conventional example. 14... Center differential 21... Front wheel side output shaft 22... Rear wheel side output shaft 30... Viscous multi-plate clutch (differential limiting device) 31.3
2...Spline 33...Spline wheel 34...Operation lever

Claims (2)

[Claims] (1) A center differential that distributes and transmits the power input from the transmission to the front and rear wheels, and a center differential that applies a predetermined coupling force between the front wheel output shaft and the rear wheel output shaft of this center differential. In a four-wheel drive device, the differential limiting device is arranged at a position where differential limiting is performed with respect to the center differential, and a differential limiting device which performs differential limiting with respect to the center differential. 4. The center differential is provided so as to be able to be switched between a position where the center differential is released and a position where the front wheel output shaft and the rear wheel output shaft of the center differential are directly connected through a part of the differential limiting device. Wheel drive. (2) The four-wheel drive device according to claim 1, wherein the differential limiting device is provided so as to be able to be switched to each of the above positions by sliding an output shaft of a center differential.