JPH01275223A - Power transmission mechanism for four-wheel drive vehicle - Google Patents

Abstract

PURPOSE:To simplify a change-over mechanism section of a power transmission mechanism which transmits power to wheels through a viscous coupling, by providing the viscous coupling and a changeover mechanism for changing over the transmission mechanism between a full-time mode and a low speed rigid four-wheel mode, on an power take-off shaft. CONSTITUTION:A torque is transmitted from an input shaft 22 to a high gear 32 and a low gear 35 on a drive shaft 31 through an input gear 25 and counter gears 29, 30. A clutch gear 31 is integrally incorporated with a casing 39 of a viscous coupling 38 in which outer plates 40 and inner plates 41 are alternately arranged and which is fitted on the drive shaft 31. Further, clutch gears 35, 36 are integrally incorporated with the high and low gears 32, 35. Accordingly, when a coupling sleeve 42 is meshed with the clutch gear 53 and a hub 34, the transmission mechanism is changed over into a high speed full-time 4WD mode while when the sleeve 42 is meshed with the clutch gears 36, 37 and the hub 34, it is changed over into a low speed rigid 4WD mode.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a power transmission mechanism for a viscous coupling type full-time four-wheel drive vehicle.

[Prior Art] As a conventional power transmission mechanism of a viscous coupling type full-time four-wheel drive vehicle, there is one shown in FIG. 3, for example.

In FIG. 3, when the coupling sleeve 1 is switched to the high-speed full-time 4WD position, the rotational driving force of the engine is applied to the input shaft 2, the hub 3, the coupling sleeve 1, the clutch gear 5, the low-speed gear 6, and the main shaft 7. The signal is then transmitted to the rear wheels. On the other hand, drive sprocket 8, chain 9, driven sprocket 1 to 10.
It is transmitted to the front wheels via the viscous coupling 11 and the front drive shaft 12. In this case, when a relative rotation difference occurs between the front wheels and the rear wheels, a rotation difference occurs between the outer plate 16 and the inner plate 17 of the viscous coupling 11, and a driving force (torque) corresponding to the rotation difference is applied to the front drive. The signal is transmitted to the shaft 12, resulting in a high-speed full-time 4WD driving state.

Also, when the coupling sleeve 1 is switched to the low-speed rigid 4WD position, the rotational driving force of the engine is transferred to the input shaft 2, the hub 3, the coupling sleeve 1,
The signal is transmitted to the rear wheels via the clutch gear 4, low-speed drive gear 13, counter gears 14, 15, low-speed gear 6, and main shaft 7.

On the other hand, a drive sprocket 8, a chain 9, a driven sprocket 10, a clutch gear 20. The signal is transmitted to the front wheels via the coupling sleeve 18, hub 19, and front drive shaft 12, resulting in a low-speed rigid 4WD running state.

[Problems to be Solved by the Invention] However, in such a conventional viscous coupling type full-time 4WD vehicle power transmission mechanism, the low-speed rigid 4WD position is sometimes used in an emergency manner. In many cases, a viscous lock mechanism is provided because it is necessary to transmit a large torque for use, but the structure becomes complicated because the high/low speed switching mechanism and the viscous lock mechanism are constructed separately. Furthermore, since the low speed gear section and the power take-off section for the front wheels are connected in series, there is a problem in that the total length of the T/F unit becomes long.

Therefore, there was a problem in that it was impossible to transmit driving force without loss.

[Means for Solving the Problems] The present invention has been made in view of these conventional problems.The present invention has been made in view of the problems of the conventional art. By arranging viscous couplings on the front and rear output shafts and concentrating the switching mechanism between high-speed full-time 4WD and low-speed rigid 4WD in one place, the structure of the switching mechanism becomes simple, and the structure of the switching mechanism is simplified. Since the lower part also serves as a gear combination for low speed gears, the overall length of the T/F unit can be shortened, resulting in a compact and simple structure.
The purpose is to provide a power transmission mechanism for wheel drive vehicles.

In order to achieve this object, the present invention provides a viscous coupling type full-time four-wheel drive vehicle that transmits rotational driving force of an engine to front wheels or rear wheels via a viscous coupling. 4
A switching mechanism for switching to a wheel drive position or a low-speed rigid four-wheel drive position is provided on the front and rear output shafts.

[Function] In the present invention, a viscous coupling and a high-speed full-time 4WD-low-speed rigid 4WD switching mechanism are arranged on the front and rear output shafts. Therefore, the structure of the switching mechanism becomes simple and easy and reliable switching operation is possible.

Furthermore, since the gear offset section also serves as a gear combination for the low speed stage, the overall length of the T/F unit can be shortened, and the overall structure can be made compact and simple.

[Example] Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention.

First, to explain the structure of a power transmission mechanism of an FR-based full-time 4-wheel drive vehicle with direct drive on the rear wheels and viscous coupling drive on the front wheels, as an example, in FIG.
1 is the case, 22 is the bearing 23.24 in the case 21
an input shaft rotatably supported via the 2
'5 is an input gear integrally formed with the input shaft 22.

26 is a counter shaft rotatably supported by the case 21 via bearings 27 and 28; 29 is a counter high gear integrally formed with the counter shaft 26 and meshes with the input gear 25; and 30 is also integrally formed with the counter shaft 26. It is a counter low gear.

On the other hand, 31 is the drive shaft which is the rear wheel side output shaft,
32 is a high gear which meshes with the counter high gear 29 and is rotatably attached to the drive shaft 31;
3 is a clutch gear integrally formed with the high gear 32; 34;
is a hub integrally formed with the drive shaft 31.

Further, 35 is a low gear meshing with the counter low gear 30, 36 is a clutch gear integrally formed with the low gear 35, and 37 is a clutch gear connected to the case 39 of the viscous coupling 38.

The viscous coupling 38 has an outer plate 40 built into the case 39 and an inner plate 41 built into the drive shirts 1-31, which are arranged alternately on the drive shafts 1-31.

42 is a coupling sleeve, and when the coupling sleeve 42 is engaged with the clutch gear 33 and the hub 34, it is switched to the high-speed full-time 4WD position, and when it is engaged with the clutch gear 36, 37 and the hub 34, it is switched to the low-speed full-time 4WD position. It can be switched to rigid 4WD position. The coupling sleeve 42, hub 34, and clutch gear 33°36.37 are all high-speed full-time 4WD.
-Low speed rigid 4. It constitutes a WD switching mechanism 43.

Next, the effect will be explained.

First, the coupling sleeve 42 is fastened to the high speed full time 4.
The power flow when switching to the WD position will be explained.

The rotational driving force of the engine is input to the shirt 122,
Input gear 25, counter high gear 29, high gear 32, clutch gear 33, coupling sleeve 42
, the hub 3I4, and the drive shirts 1 to 31 to the rear propeller shaft, while the drive shaft 31
, the inner plate 41 and the outer plays 1 to 40, and are transmitted to the fluorocarbon 1 and the propeller shirts 1 to 1.

In this case, when a rotation difference occurs between the outer plate 40 and the inner plate 41 due to rear tire slipping, the transmission of driving force begins due to the shear resistance of the silicone oil filling the gap, and the rotation difference is reduced. The larger the value, the larger the transmitted torque. In other words, if there is a difference in rotation between the front and rear wheels, such as when the rear wheels slip, the
It becomes a WD running state.

Next, attach the coupling sleeve 42 to the low-speed rigid 4WD
The power flow when switching to the position will be explained.

The rotational driving force of the engine is transmitted to the rear propeller shirt 1 through the input shaft 22, input gear 25, counter high gear 29, counter low gear 30, low gear 35, clutch gear 36, coupling sleeve 42, hub 34, and drive shaft 31. On the other hand,
It is transmitted to the front propeller shaft via the coupling sleeve 42, clutch gear 37, viscous cup=9-ring case 39.

Therefore, the viscous couplings 38 are arranged on the front and rear output shafts, and the high-speed full-time 4WD - low-speed rigid 4WD
By concentrating the WD switching mechanism in one place, the structure of the switching mechanism becomes simple, and since the gear offset section also serves as a gear combination for low gears, the overall length of the T/F unit can be shortened, resulting in a The structure can be made compact and simple.

FIG. 2 is a diagram showing another embodiment of the present invention.

This embodiment is an example in which the present invention is applied to an FF-based full-time four-wheel drive vehicle with front wheel direct drive and rear wheel viscous coupling drive.

In FIG. 2, the viscous coupling 38 is arranged on the rear wheel side of the drive shaft 31, which is the front and rear output shaft, and the switching mechanism 4 between high-speed full-time 4WD and low-speed rigid 4WD
3 is arranged on the front wheel side of the drive shaft 31.

In this embodiment as well, the same effects as in the above embodiment can be expected.

[Effects of the Invention] As explained above, according to the present invention, viscous couplings are arranged on the front and rear output shafts, and the high-speed full-time 4WD-low-speed rigid 4WD switching mechanism is concentrated in one place, so that the switching mechanism The structure of the section is simple, allowing for easy and reliable switching operations.

Furthermore, since the gear offset portion also serves as a gear combination for the low speed stage, the overall length of the T/F unit can be shortened, and the overall structure can be made compact and simple.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing one embodiment of the present invention, FIG. 2 is an overall configuration diagram showing another embodiment of the invention, and FIG. 3 is an overall configuration diagram showing a conventional example. In the figure, 21...Case, 22...Input shaft, 23...Bearing, 24...Bearing, 25...Implement 1 to gear, 26...Counter shaft, 27...Bearing, 28... Bearing, 29... Counter high gear, 30... Counter low gear, 31... Drive shaft, 32... High gear, 33... Clutch gear, 34... Hub, 35... Low gear, 36...Clutch gear, 37...Clutch gear, 38...Viscous coupling, 39...Case, 40...Outer plate, 41...Inner plate, 42...Coupling Sleeve, 43... switching mechanism. Patent applicant: Fuji Iron Works Co., Ltd.

Claims (1)

[Claims] In a viscous coupling type full-time four-wheel drive vehicle that transmits the rotational driving force of the engine to the front wheels or rear wheels via a viscous coupling, the viscous coupling and the full-time four-wheel drive position or low-speed rigid four-wheel drive A power transmission mechanism for a four-wheel drive vehicle, characterized in that a switching mechanism for switching positions is provided on the front and rear output shafts.