JP2581206Y2 - Viscous coupling - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a viscous coupling for transmitting torque through a viscous fluid.

[0002]

2. Description of the Related Art In general, a viscous coupling used as a differential device in a power transmission system, for example, between the front and rear axles of a four-wheel drive vehicle, has first and second rotatably arranged first and second rotatable members.
Transmission member, two sets of plates, and a working chamber filled with a viscous fluid, wherein the first set of plates is slidable in the rotation axis direction of the first transmission member, and First
A second plate set slidable in the rotation axis direction of the second transmission member and rotatably disposed with the second transmission member. The plates of the first and second plate sets are alternately arranged in the working chamber.

In such a viscous coupling, a spacer ring is provided between the plates of one of the plate sets so that the plates of the first and second plate sets have a gap therebetween. ing. Therefore, each plate of the plate set in which the spacer ring is not provided can be moved by the gap in the rotation axis direction.

Therefore, when the first and second transmission members rotate relative to each other and a differential torque is generated between the first and second plate sets, each plate of the plate set having no spacer ring is provided. Move in the direction of the rotation axis due to the pressure difference generated between each plate set. In particular, when the viscous coupling is operated for a long time with a relative rotation of a certain degree or more, the internal temperature rises, the silicone oil expands, and the air enclosed with the silicone oil is compressed, so that the air bubbles are generated in each plate. Cannot absorb the pressure difference generated on both sides of the plate set, and a so-called "hump phenomenon" occurs in which the plates of one plate set movable in the axial direction start to come into direct contact with the plates of the other plate set. . At this time, the torque transmission is switched from the torque transmission due to the viscosity of the silicon oil between the plate pairs to the torque transmission due to the frictional contact of the plates between the plate pairs, so that the transmission torque increases rapidly.

Therefore, such a viscous coupling is used as a power transmission device in a power transmission system between the front and rear axles of a 4WD vehicle, or as a differential limiting device in a power transmission system between left and right wheels of a rear wheel drive vehicle. In this case, by effectively utilizing the hump state, even if one of the wheels spins, the driving force can be transmitted to the other wheel with high efficiency.
It is possible to improve the ability of the vehicle to travel on a bad road.

It is also known that by forming a slit or a circular opening in each plate of the viscous coupling as described above, the torque transmitting ability of the viscous coupling can be improved. Therefore, various openings are formed in each of the outer plate and the inner plate constituting the first and second plate sets.
The inner plate 70 shown in FIG. 6 includes a plurality of circular holes 71 arranged at equal intervals in the circumferential direction, and a parallel slit 72 extending radially outward from the circular hole 71 and reaching the outer peripheral edge.
Is formed.

[0007]

By the way, the outer plate or the inner plate having the slits extending in the radial direction and reaching the peripheral edge as described above has a sharp corner portion at the tip. For example, in the case of the inner plate 70 shown in FIG. 6, sharp edges 73 and 74 are formed at the circumferential edges of the blade portions 75 formed by the slits 72.

In the case where the slit extending in the radial direction and reaching the peripheral edge is a viscous coupling formed in at least one of the outer plate and the inner plate, one of the plates moves in the axial direction due to a hump phenomenon or the like. When the adjacent plates come into contact with each other,
It is easy for the pointed corners as described above to make local point contact with the adjacent plate that rotates relatively, and such local point contact of the plate generates high heat due to frictional heat, which heats the silicone oil. There is a problem of deterioration. In particular, when thermal distortion occurs in the plate, local point contact of the plate is remarkable.

Therefore, an object of the present invention is to solve the above-mentioned problems, and by preventing a local point contact when each plate set comes into contact with each other by a simple structure,
An inexpensive viscous coupling with improved differential durability is provided.

[0010]

SUMMARY OF THE INVENTION The object of the present invention is to provide first and second transmission members which are rotatably arranged, a working chamber filled with a viscous fluid, and a first transmission member. A first set of plates rotationally engaged, and a second set of plates alternately arranged in the working chamber and non-rotatably engaged with the second transmission member; In the viscous coupling having, each plate constituting at least one plate set has a plurality of slits extending in the radial direction at a peripheral edge opposite to the engaging peripheral edge engaging with the transmission member, The outer peripheral edge of the blade portion of the plate formed by the slit is
This is achieved by the viscous coupling, which is characterized by being formed with a gentle curve having no corners that cause a substantial point contact .

[0011]

According to the above construction of the present invention, the outer peripheral edge of the blade portion of the plate formed by the slit is formed in the adjacent plate.
It is composed of a gentle curve having no corners that cause local point contact with the rate, so that even when adjacent plates come into contact with each other, local point contact can be avoided.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to FIGS. 1 to 5 and FIG. First, the configuration of the power system of a 4WD vehicle using one embodiment of the present invention will be described with reference to FIG. The power system includes an engine 1, a transmission 3, a front differential 5 (a front-wheel-side differential device), left and right front wheels 7 and 9, a transfer 11, a viscous coupling 13 of this embodiment, a propeller shaft 15,
It comprises a rear differential 17 (differential device on the rear wheel side), left and right rear wheels 19, 21 and the like.

Next, referring to FIG.
3 will be described. The housing 33 (first transmission member) and the hub 35 (second transmission member) are relatively rotatably arranged. The hub 35 is connected to the output shaft of the transfer 11 by an integral spline 37, and is rotated by the driving force from the engine 1. The housing 33 is provided with a propeller shaft 1 by bolts screwed into bolt holes 39.
The flange 3 is connected to the connection shaft 27 on the fifth side.
A bearing 29 is provided between the transfer shaft 3 and the output shaft of the transfer 11.

A working chamber 45 is formed between the housing 33 and the hub 35. The working chamber 45 is filled with high-viscosity silicone oil (viscous fluid). Further, a bearing 41 is arranged between the housing 33 and the hub 35, and X rings 47, 49 (X-shaped seals in cross section) and backup rings 51, 53 are arranged to seal the working chamber 45 in a liquid-tight manner. I keep it.

As shown in FIG. 2 in an enlarged manner, the outer plate 55 and the inner plate 5
7 are alternately arranged. The outer plate 5
5 (first plate) is spline-connected to a spline 63 formed on the inner periphery of the housing 33 so as to be movable in the axial direction. A spacer ring 61 is arranged between the outer plates 55. The inner plate 5
Reference numeral 7 is spline-connected to a spline 62 formed on the outer periphery of the hub 35 so as to be movable in the axial direction.

As shown in FIG. 3, each inner plate 5
7 are formed with spline teeth 67 for spline engagement with the hub 35 at the inner peripheral edge thereof, and at the outer peripheral edge thereof are formed a plurality of notches, which are a plurality of notches extending inward in the radial direction, at equal intervals. Is formed. Therefore, a blade portion 58 extending outward in the radial direction is formed on the outer peripheral edge portion of the inner plate 57, and the slit 65 is formed by a gentle curve. The outer periphery of the portion 58 is
It does not have corners that cause local point contact with the plate .

As shown in FIG. 4, spline teeth 66 for spline engagement with the housing 33 are formed on the outer peripheral edge of each outer plate 55, and the inner peripheral edge thereof has a radially outer portion. Slits 64, which are a plurality of notches extending in the direction, are formed at equal intervals. Therefore,
A blade portion 59 extending inward in the radial direction is formed at an inner peripheral edge portion of the outer plate 55. The slit 64 is formed by a gentle curve,
The outer peripheral edge of the blade portion 59 formed by
It has no corners that create local point contact with the abutting plate .

Therefore, as shown in FIG. 5, the inner plates 57 alternately arranged with the outer plates 55 in the working chamber 45 move in the axial direction due to a hump phenomenon or the like.
Even when the blade portion 58 comes into contact with the adjacent outer plate 55, the blade portion 58 does not have a corner portion and does not locally come into strong point contact with the plate surface of the outer plate 55. Further, the blade portion 59 of the outer plate 55 also has no corner portion, and does not locally come into strong point contact with the plate surface of the inner plate 57.

Therefore, it is possible to avoid local point contact between the plates and prevent deterioration of the silicone oil due to frictional heat. Therefore, the differential durability of the viscous coupling is improved. Next, the function of the viscous coupling 13 will be described in accordance with the power performance of the vehicle shown in FIG.

The rotation of the engine 1 is controlled by the transmission 3
, And is divided and output from the front differential 5 to the left and right front wheels 7 and 9. Further, the rotation transmitted to the viscous coupling 13 via the transfer 11 is transmitted to the rear differential 17 via the transmission shaft 27 and the propeller shaft 15 and is divided and output to the right and left rear wheels 19 and 21. When the rotational speed difference due to the relative movement between the front and rear axles is small, such as when traveling on a good road, the rotational speed difference is absorbed by the viscous coupling 13 and almost no driving force is transmitted to the rear wheels 19 and 21.
Accordingly, the vehicle is in the front-wheel drive 2WD state, and the fuel economy is improved, and the tight corner braking phenomenon does not occur even in a low-speed sudden turn such as in a garage or a U-turn.

When the front wheels 7, 9 run idle on a rough road or the like, a rotational speed difference occurs between the front and rear axles, and when the rotational speed difference between the rotation of the housing 33 and the rotation of the hub 35 is large, the viscous Due to the torque transmission characteristics of the coupling 13,
Driving force is transfer 11, viscous coupling 1
3. The vehicle is divided and output from the propeller shaft 15 to the left and right rear wheels 19 and 21 via the rear differential 17, and the vehicle enters the 4WD state, so that high running performance is obtained.

Further, when the front wheels 7, 9 are stuck in mud or the like and the vehicle is stuck, the rotational speed difference between the front and rear axles increases and relative rotation occurs continuously for a long time. The coupling 13 produces a hump condition. For this reason, the transmission torque of the viscous coupling 13 sharply increases and the transmission efficiency of the driving force to the rear wheels 19 and 21 increases, so that a high driving force is generated in the rear wheels 19 and 21 and escape from the stack. Becomes possible. On this occasion,
According to the present invention, local point contact between the plates is avoided, and the deterioration of the silicone oil due to frictional heat is prevented. I will not do it.

The shape of the slit in the present invention is not limited to the shape of the above-described embodiment, and various shapes can be adopted as long as the blade does not have a sharp corner. For example, a plate in which slits and circular holes are alternately arranged in the circumferential direction may be used. Further, in the above-described embodiment, the example in which the viscous coupling of the present invention is arranged on the propeller shaft of a 4WD vehicle has been described. However, the present invention is not limited to this, and other devices such as a differential limiting device for a rear wheel drive vehicle are provided. And the housing and the hub can take various shapes accordingly.

[0024]

According to the viscous coupling of the present invention, the blade portion of the plate formed by the slit is
The outer peripheral edge is formed by a gentle curve having no corner that causes local point contact with an adjacent plate, and avoids local point contact even when adjacent plates come into contact with each other. Can be. Therefore, the respective plate sets do not make point contact with each other, and the respective plates are less likely to generate frictional heat. Therefore, deterioration of the silicone oil due to the heat is prevented, and the differential durability of the viscous coupling is improved.

Therefore, it is possible to provide an inexpensive viscous coupling having a simple structure and improved differential durability.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a viscous coupling according to an embodiment of the present invention.

FIG. 2 is a partially enlarged view of the viscous coupling shown in FIG.

FIG. 3 is a front view of the inner plate shown in FIG. 1;

FIG. 4 is a front view of the outer plate shown in FIG. 1;

FIG. 5 is a cross-sectional view of the viscous coupling shown in FIG. 1;

FIG. 6 is a front view of a conventional inner plate.

FIG. 7 is a skeleton diagram showing a power system of a vehicle using the viscous coupling shown in FIG. 1;

[Explanation of symbols]

 Reference Signs List 1 engine 3 transmission 5 front differential 7 front wheel 9 front wheel 11 transfer 13 viscous coupling 15 propeller shaft 17 rear differential 19 rear wheel 21 rear wheel 29 bearing 33 housing (first transmission member) 35 hub (second transmission member) 37 spline 39 Bolt hole 41 Bearing 45 Working chamber 47 X-ring 49 X-ring 51 Backup ring 53 Backup ring 55 Outer plate (first plate) 57 Inner plate (second plate) 58 Blade part 59 Blade part 61 Spacer ring 62 Spline 63 Spline 64 Slit 65 Slit 66 Spline tooth 67 Spline tooth 70 Inner plate 71 Circular hole 72 Slit 73 Corner part 74 Corner part 75 Blade part

Claims (1)

(57) [Scope of request for utility model registration] A first and a second rotatably arranged first and second rotatable members.
A transmission member, a working chamber filled with a viscous fluid, a first plate set non-rotatably engaged with the first transmission member,
In the viscous coupling having the first plate set and the second plate set alternately arranged in the working chamber and non-rotatably engaged with the second transmission member, at least one plate set is constituted. Each plate has a plurality of slits extending in the radial direction at the peripheral edge opposite to the engaging peripheral edge engaged with the transmission member, the outer peripheral edge of the blade portion of the plate formed by each slit , Adjacent
Have no corners that cause local point contact with the plate
A viscous coupling characterized by being formed with a gentle curve .