JPH01182632A - Viscous coupling - Google Patents

Abstract

PURPOSE:To furthermore improve response for torque transmission to rear wheels as well as response for differential restriction by providing No.1 or No.2 rotating member monolithically with an electromagnet the transmitting characteristics of which is instantly changeable so that the line of magnetic force of it easily passes through. CONSTITUTION:When apparent viscosity of working fluid is changed in the magnetic field of an electromagnet 17, or a space between No.1 and No.2 resistance plates 15 and 16 is regulated, torque characteristics is instantly changed. Hence, when a viscous coupling 6 of this type is applied to four wheel drive based on front-engine front-drive, response for torque transmission to rear wheels can be improved. And when it is applied to a differential restriction device, response for differential restriction can be improved. In addition, the installation of the electromagnet 17 monolithically with No.1 or No.2 rotating member 19 and 13 allows the line of magnetic force of the electromagnet 17 to easily pass through No.1 or No.2 rotating member 19 and 13. Hence, both response for troque transmission and response for differential restriction can be furthermore improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention (Field of Industrial Application) This invention relates to a viscous coupling using a viscous fluid.

(Prior Art) As a conventional viscous coupling, there is, for example, the one shown in FIG. 3 (see Japanese Patent Laid-Open No. 61-65918). In the figure, 101 is a first rotating member connected to a drive shaft, 102 is a second rotating member connected to a driven wheel, and this first rotating member 101 and second rotating member 10
It is possible to rotate relative to 2. The first rotating member 101 and the second
A closed working chamber 103 is defined by the rotating member 102, and this working chamber 103 is filled with a viscous fi fluid. A first resistance plate 104J3 and a second resistance plate 105 are housed in the working chamber 103, and the first resistance plate 104 and the second resistance plate 105 are alternately splined to the first rotation member 101 and the second rotation member 102, respectively. combined. Between the first resistance plate 104 and the second resistance plate 105
Disc springs 106 and 107 are respectively interposed between them. Further, a pressing body 108 is housed in the working chamber 103,
This pressing body 108 is moved from left to right in the figure by a piston 11o that is acted upon by a hydraulic medium fed from a conduit 109.
n”.

This viscous coupling is interposed, for example, between the transfer and blower shaft of a front engine front drive (FF) based four-wheel drive vehicle, and the first rotating member 101 and the second rotating member 102 are connected to the transfer and propeller, respectively. connected to the shaft. When a vehicle slips on a rough road where the front wheels have a low road surface friction coefficient, a difference in rotational speed occurs between the front wheels and the rear wheels. Therefore, the first resistance plate 104 and the second resistance plate 105 rotate relative to each other to shear the viscous fluid. The shearing force of this viscous fluid is transmitted as torque to the rear wheels, which push the vehicle out of the slip state.

At this time, in order to quickly transmit large torque to the rear wheels, the pressing body 108 is moved to the left in FIG. 1. The spacing between the second resistance plates 104 and 105 is reduced, and the filling rate of the viscous fluid is increased to increase shear resistance.

In addition, viscous couplings are also used, for example, as differential limiting devices for limiting differential rotation between left and right wheels of a vehicle. In this case as well, in order to quickly limit the differential motion between the left and right wheels, the pressing body 108 is moved in the same manner as the first. The spacing between the second resistance plates 104 and 105 is reduced to increase the shear resistance of the viscous fluid.

(Problem to be Solved by the Invention) However, in such a conventional viscous coupling, a method is adopted in which the pressing body 108 is moved by the piston 110 in order to quickly transmit large torque to the rear wheel. Ta. -With this kind of mechanical system inside the membrane, there was a limit to how quickly it could transmit large torque to the rear wheels or quickly limit differential movement between the left and right wheels. . That is, there was a problem in that the responsiveness of torque transmission and differential limiting was poor.

[Structure of the Invention] (Means for Solving the Problems) In order to solve such problems, the present invention includes a first rotating member and a second rotating member that are relatively rotatable;
A first resistance plate and a second resistance plate alternately engaged with each of the first rotation member and the second rotation member;
a working chamber in which a resistance plate and a second resistance plate are housed and defined by the first rotating member and the second rotating member; In a viscous coupling equipped with a working fluid that is sheared by An electromagnet that instantly changes the torque transmission characteristics of the coupling is integrally attached to the first rotating member or the second rotating member in order to facilitate the passage of the magnetic field lines of the electromagnet through the first rotating member or the second rotating member. The configuration is as follows.

(Function) When the apparent viscosity of the working fluid is changed by the magnetic field of the electromagnet and/or the distance between the first resistance plate and the second resistance plate is adjusted, the torque transmission characteristics of this viscous coupling immediately change. . Therefore, when this viscous coupling is applied to a FF-based four-wheel drive vehicle,
If the front wheels slip, torque can be quickly transferred to the rear wheels. Further, when this viscous coupling is used in a differential limiting device, the differential between the left and right wheels can be quickly limited. In addition, since the electromagnet is integrally provided with the first rotating member or the second rotating member, the lines of magnetic force of the electromagnet can easily pass through the first rotating member or the second rotating member. Therefore, the aforementioned torque is transmitted to the rear wheels more quickly.

(Example) The present invention will be explained below based on the drawings.

FIGS. 1 and 2 are diagrams showing an embodiment of the viscous coupling according to the present invention. This embodiment is an example in which a viscous coupling is interposed between the transfer and propeller shaft in FF-based four-wheel drive.

First, the configuration will be explained. In FIG. 1, 1 is a transfer case, and this case 1 includes a bearing case 2, a pair of tapered roller bearings 3 (however, only one of the pair is shown), and a structure interposed between the pair of tapered roller bearings 3. The output shaft 5 of the transfer is rotatably supported via a spacer 4 and the like.

A viscous coupling 6 is interposed between the output shaft 5 and a propeller shaft (not shown). That is, a first rotating member 9 consisting of an inner hub 7 that is spline-coupled to the output shaft 5 and an inner cylinder 8 fixed to the inner hub 7 is mounted so as to rotate integrally with the output shaft 5. There is.

On the outside of the first rotating member 9, there is an outer opening R10 disposed on the same axis as the inner cylinder 7, and a left end wall member 11 and a right end wall member 1 fixed to both ends of the outer cylinder 10.
A second rotating member 13 consisting of 2 is disposed.

A closed working chamber 14 is defined by the first rotating member 13 and the second rotating member 13, and a magnetic fluid 31 is sealed in the working chamber 14 as a working fluid. The working chamber 14 has a first tube made of non-magnetic material (e.g. 18-8 stainless steel).
A resistance plate 15J: and a second resistance plate 16 are housed, and the first resistance plate 15J3 and the second resistance plate 16 are spline-coupled alternately to the outer peripheral wall of the inner cylinder 8 and the inner peripheral wall of the outer cylinder 10, respectively. ing. Therefore, when the first rotating member 9 and the second rotating member 13 rotate relative to each other, the first resistance plate 15 and the second resistance plate 16 rotate relatively to shear the magnetic fluid 31.

By the way, the magnetic fluid 31 is a solid-liquid multiphase fluid in which fine particles of magnetite (Fe304) with a diameter of 1Q-8m are dispersed in a silicone oil solvent, and the apparent viscosity of this solid-liquid multiphase fluid decreases in the magnetic field. (viscosity in one direction in a solid-liquid multiphase fluid) changes. Here, in this magnetic fluid 31, the apparent viscosity in the shearing direction by the first resistance plate 15 and the second resistance plate 16 is set to be high<7. To that end, the lateral opening fli1
An electromagnet 17 having a coil wound in the circumferential direction of the electromagnet 17 is disposed on the side of the working chamber 14. That is, the magnetic material holder 1
The electromagnet 17 enclosed in the electromagnet 8 is rotatably supported by the bearing case 2 on the side of the first rotating member 13 and the second rotating member 9 in the axial direction thereof via a needle bearing 32. . Here, the outer peripheral end of the holder 18 is fixed to the outer cylinder 10 via the first magnetic induction member 27. Further, the inner circumferential end of this holding body 18 is fixed to the left end wall member 11 via a second magnetic attraction member 28 .

Therefore, the electromagnet 17 is provided integrally with the second rotating member 13 without an intervening air gap portion (gap) having high magnetic resistance. Here, since the electromagnet 17 is provided integrally with the second rotating member 13, the second rotating member 13
When rotates, it rotates together with this. Therefore, electromagnet 1
Cheers to 7! A conductive wire for passing current is attached to the holder 18 via a slip ring (not shown).

When an excited lightning current flows through the electromagnet 17, lines of magnetic force C pass as shown in FIG.
For example, 18-8 stainless steel), and both sides 1
l b i, a magnetic material (for example, carbon 0.05 to 0.
1% carbon steel), and the central part 11a and both side parts 11
b is fixed by welding or the like. Further, since there is no air gap with high magnetic resistance between the electromagnet 17 and the second rotating part 4413, the lines of magnetic force generated by the electromagnet 17 are not subjected to magnetic resistance and are transferred to the first magnetic induction member 27 and the second magnetic induction member 4413. It passes through the guiding member 28 and further into the working chamber 14 .

The right end wall member 12 is connected to the propeller 11 foot, so that the torque transmitted to the second rotating member 13 is transmitted to the rear wheels via the propeller shaft, differential, rear wheel drive shaft, etc. The left end wall member 11 and the right end wall member 12 are supported by the inner hub 7 and the output shaft 5 via a needle bearing 22 and a rolling bearing 23, respectively. Note that seal members 24 and 25 are interposed between the left end wall member 11 and the right end wall member 12 and the inner hub 7, respectively.

Next, the effect will be explained. When a vehicle travels straight on a paved road, engine torque is transmitted from the transmission to the front drive shaft, driving the vehicle in front-wheel drive. At this time, the first rotating member 9 and the second rotating member 13 of the viscous coupling 6 rotate at the same time.

Next, when the front wheels slip when the vehicle is driving on a rough road with a small coefficient of road friction, the front wheels, which are directly driven by the engine, receive less resistance from the road surface.
The torque transmitted to the front wheels is only small. Here, since the rear wheels are rotating less than the engine side rotation speed (front wheel drive shaft), the second rotating member 13 connected to the rear wheel drive shaft rotates less than the first rotating member 9 connected to the front wheel drive shaft. do. Therefore, a difference in rotational speed occurs between the front wheel drive shaft and the rear wheel drive shaft, that is, between the first rotation member 9 and the second rotation member 13, and the first resistance plate 15 and the second resistance plate 16
Rotates relative to f! to shear the magnetic fluid. Fi-4ru.

At this time, when an excitation current is applied to the electromagnet 17, lines of magnetic force pass through the working chamber 14 in the direction shown in FIG. 1, creating a magnetic field. In this way, when the magnetic field lines pass through the working chamber 14,
The apparent viscosity of the magnetic fluid immediately increases by 1 in the shear direction. Therefore, the shear resistance of the magnetic fluid in the shear direction immediately increases. Therefore, the shearing force of the magnetic fluid increases immediately, and this large shearing force can be quickly transmitted as torque from the rear wheel drive shaft to the rear wheels.

That is, the responsiveness of torque T to the rear wheels can be improved. As a result, the rear wheels push the vehicle,
To quickly get a front wheel out of a slipping state.

Here, the electromagnet 17 is connected to the first magnetic induction member 27 without interposing an air force part between the electromagnet 17 and the second rotating member 13.
and are integrally provided via the second magnetic induction member 28. Therefore, the lines of magnetic force generated by the electromagnet 17 pass through the first magnetic induction member 27 and the second magnetic induction member 28 and further into the working chamber 14 without being subjected to magnetic resistance.

Therefore, the density of the lines of magnetic force passing through the working chamber 14 increases, and the magnetic flux becomes stronger. As a result, the responsiveness of the torque T transmitted to the rear wheels is further improved.

On the other hand, in order to improve the responsiveness of torque transmission to the rear wheels, we used a magnetic fluid in which fine magnetite particles were dispersed in silicone oil as the working fluid, but this is not limited to silicone oil (viscous fluid). It's fine just by itself. In this case, the first resistance plate 15 and the second resistance plate 16 housed in the working chamber 14 are made of magnetic material (for example,
Charcoal f with 0°05~0.1% carbon! i). Electromagnet 1
When an excitation current is passed through the working chamber 14, lines of magnetic force C pass through the working chamber 14, creating a magnetic field. First resistance plate 15 and second resistance plate 16
Since they are made of magnetic material, the first resistance plate 15 and the second resistance plate 16 are attracted to each other and tend to gather on the left end wall member 11 side of the working chamber 14. 1st
The distance between the resistance plate 15 and the second resistance plate 16 is small (and in some cases, they come into contact with each other. Therefore, the first low resistance plate 15
The shear resistance of the silicone oil sheared by the second resistance plate 16 immediately increases. Therefore, the shearing force of the silicone oil increases immediately, and this large shearing force can be quickly transmitted as torque from the rear wheel drive shaft to the rear wheels. In this case, the magnetic fluid may be used as is, and if used as is, the transmitted torque of the viscous coupling will increase synergistically.

By the way, the torque T transmitted to the rear wheels according to the differential rotation speed ΔN between the first rotating member 9 and the second rotating member 13 can be calculated as shown in FIG. As shown in FIG. 2, it is possible to obtain a characteristic that is a difference between characteristic A when no excitation current is applied and characteristic B when maximum current is applied.

Therefore, the electromagnet 17
By changing the strength of the excitation current instead of flowing through it, the torque T can be made to have the desired characteristics, and the vehicle can run stably.

On the other hand, when using this viscous coupling as a differential limiting device to limit the differential rotation between the left and right wheels of a vehicle, when an excitation current is passed through the TX magnet, the apparent viscosity of the magnetic fluid is immediately increased. can do. Therefore, the shear resistance of the magnetic fluid can be immediately increased, and the differential motion between the left and right wheels can be quickly limited. That is, the responsiveness of differential limiting can be improved. Further, in this case as well, since no air gap is present as described above, the responsiveness of this differential limiting is further improved.

Furthermore, when the car is in the garage, there will be a difference in rotational speed between the front and rear drive shafts, as well as between the left and right wheels, but this difference in rotational speed will be absorbed by the viscous coupling. The excitation current is cut to keep the shear resistance of the magnetic fluid low.

Furthermore, although the above embodiments have been explained using a magnetic fluid and a resistance plate made of a non-magnetic material, it is also possible to use a viscous fluid that is not magnetic and a resistance plate made of a magnetic material. It may also be combined with a resistance plate made of magnetic material.

[Effects of the Invention] As explained above, according to the present invention, the apparent viscosity of the working fluid can be changed by the magnetic field of the electromagnet and/or the distance between the first resistance plate and the second resistance plate can be adjusted. Accordingly, the shear resistance of the magnetic fluid can be changed instantly. Therefore, this viscous coupling is
For example, when interposed between the transfer and propeller shaft of an FF-based four-wheel drive vehicle, torque can be quickly transmitted to the rear wheels. That is, the responsiveness of torque transmission to the rear wheels can be improved. As a result, the rear wheels can push the vehicle out, allowing the front wheels to quickly escape from the slipping state.

In addition, in order to make it easier for the lines of magnetic force of the electromagnet to pass through the first rotating member or the second rotating member, the electromagnet is provided integrally with the first rotating member or the second rotating member, so the density of the lines of magnetic force passing through the working chamber is reduced. becomes higher and the magnetic flux becomes stronger. Therefore, the responsiveness of the aforementioned torque transmission to the rear wheels is further improved.

On the other hand, when this viscous coupling is used in a differential limiting device, the differential between the left and right wheels can be quickly limited. That is, the responsiveness of differential limiting can be improved. Further, as described above, the responsiveness of this differential limiting is further improved.

FIG. 1 is a cross-sectional view of this viscous coupling, and FIG. 2 is a graph showing the characteristics of torque transmitted to the rear wheels depending on the differential rotation speed. Third
The figure is a sectional view showing a conventional viscous coupling.

9... First rotating member 13... Second rotating member 14.
... Working chamber 15... First resistance plate 16... Second
Resistance plate 17... Electromagnet 27... First magnetic induction member 28... Second magnetic induction member 31... Working fluid agent Patent attorney Yasuo Miyoshi ΔN Figure 2 High 3

Claims (1)

[Claims] A first rotating member and a second rotating member that are relatively rotatable; a first resistance plate and a second resistance plate that are alternately engaged with each of the first rotating member and the second rotating member; and the first resistance plate. and a working chamber in which a second resistance plate is housed and defined by the first rotating member and the second rotating member; In this viscous coupling, the apparent viscosity of the working fluid is changed and/or the distance between the first resistance plate and the second resistance plate is adjusted. An electromagnet that instantly changes the transmission characteristics of the electromagnet is provided integrally with the first rotating member or the second rotating member in order to make it easier for the lines of magnetic force of the electromagnet to pass through the first rotating member or the second rotating member. A viscous coupling featuring