JPH02150516A - Power transmission device - Google Patents

Abstract

PURPOSE:To attempt to enhance torque transmission responsiveness and a torque transmission amount to a wheel having a high friction coefficient by using magnetic fluid as work fluid, and pulling this magnetic fluid toward one side or other side of a working chamber by magnetic force. CONSTITUTION:As resistance acting on a front wheel driving shaft is small when a front wheel slips while a vehicle travels on a rough road of a low friction coefficient, torque transmitted to this front wheel is exhibited to small extent only. As turning amount of a rear wheel is smaller than that of the front wheel driving shaft at that time, a second rotary member 24 connected to a rear wheel driving shaft turns with turning amount smaller than that of a first rotary member 21 connected to the front wheel driving shaft, thereby a rotational difference is generated between the front wheel driving shaft and the rear wheel driving shaft, and a first resistance part 28 and a second resistance part 29 relatively rotate to shutdown the magnetic fluid. If an exciting current is fed to an electro-magnet 30 at this time, the magnetic fluid is pulled toward one side of a working chamber 27. Thus, the magnetic fluid filled in the chamber 27 is shutdown by the resistance parts 28 and 29.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a power transmission device that is incorporated into a power transmission system of a vehicle or the like and utilizes viscous fluid.

(Prior Art) As a conventional power transmission device, there is one shown in FIG. 5, for example. In the figure, 101 is a first rotating member connected to a drive shaft, and 102 is a second rotating member connected to a driven wheel.
The first rotating member 101 and the second rotating member 102 are rotating members, and the first rotating member 101 and the second rotating member 102 can rotate relative to each other. First rotating member 101
and the second rotating member 102 hermetically seal the working chamber 103.
A working chamber 103 is defined, and a viscous fluid is sealed in this working chamber 103. In order to seal the viscous fluid in the working chamber 103, an X-ring 106 as a sealing member is interposed between the first rotating member 101 and the second rotating member 102. A first resistance plate 104 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 mutually splined to the first rotation member 101 and the second rotation member 102, respectively. combined.

This viscous coupling is interposed, for example, between a transfer and a propeller shaft of a four-wheel drive vehicle based on a front engine, front drive (FF), and the first rotating member 101 and the second rotating member 102 are each connected to a transfer shaft. and the propeller shaft. When the front wheels slip on a rough road with a low coefficient of friction, a large rotational difference occurs between the front and 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 the viscous fluid at this time is transmitted as torque to the rear wheels, which push the vehicle out of the slip state.

On the other hand, when the steering wheel is turned sharply at low speeds, such as when parking in a garage, there is a difference in rotational speed between the front and rear drive shafts and between the left and right wheels, but this rotational speed difference is small, so the viscous This is absorbed by the coupling to prevent the so-called tight corner braking phenomenon from occurring.

(Problem to be Solved by the Invention) However, in such a conventional power transmission device, in order to get the vehicle out of a slip state, the torque transmitted to the rear wheels must be increased. Therefore, the filling rate of the viscous flow filling the working chamber 103 must be increased.

However, on the other hand, in order to prevent the occurrence of a tight corner braking phenomenon during low-speed large steering such as when parking the vehicle, the first resistance plate 104 and the second resistance plate 105 must be able to rotate relative to each other. Now, the filling rate of viscous fluid must be lowered. Therefore, the filling rate of the viscous fluid must be set to a certain (intermediate) filling rate in order to quickly escape from the slip state and to prevent the occurrence of tight corner braking. Therefore, in order to solve such problems, the vehicle cannot quickly escape from the slip state and the occurrence of tight corner braking phenomenon cannot be completely prevented. A first rotating member and a second rotating member that are arranged to be relatively rotatable, and fixedly attached to each of the first rotating member and the second rotating member, extending in the direction of the relative rotation center line and alternately overlapping each other. A power transmission device comprising a first resistance part, a second resistance part, and a working chamber filled with a working fluid sheared by the first resistance part and the second resistance part, wherein the working fluid is a magnetic fluid. , the magnetic fluid is drawn to one side or the other side of the working chamber by magnetic force (first invention).

Also, a first rotating member and a second rotating member are arranged to be relatively rotatable, and the first rotating member and the second rotating member are fixedly provided to each of the first rotating member and the second rotating member, and are arranged alternately in the direction of the relative rotation center line. In a power transmission device comprising a first resistance part and a second resistance part that overlap each other, and a working chamber filled with a working fluid that is sheared by the first resistance part and the second resistance part, the first resistance part and the second resistance part overlap each other. The overlapping length with the second resistive portion can be changed, and a magnet is provided to change the overlapping length using magnetic force (second invention).

(Function) When the first rotating member and the second rotating member rotate relative to each other, the first
The resistor and the second resistor shear the working fluid. At this time,
In the first invention, when the magnetic fluid is drawn to one side of the working chamber by magnetic force, the shearing force of the magnetic fluid sheared by the first resistance part and the second resistance part increases. Next, when the magnetic fluid is drawn to the other side of the working chamber by a magnet,
The shearing force of the magnetic fluid sheared by the first resistance part and the second resistance part becomes small.

In the second invention, the overlapping length is changed by moving the first resistor or the second resistor using a magnet, and as the overlapping length increases, the shearing force of the working fluid increases. Conversely, as the overlap length becomes shorter, the shearing force becomes smaller.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. Figures 1 and 2 show a first diagram of a power transmission device according to the present invention.
It is a figure without an example. This embodiment is an example in which the power transmission device of the present invention is interposed between the front wheel drive shaft and the rear wheel drive shaft of a FF-based four-wheel drive vehicle.

First, the configuration will be explained. In FIG. 1, reference numeral 1 denotes an internal combustion engine, and torque output from the internal combustion engine 1 is transmitted to a transmission 3 via a clutch 2. Torque is transmitted from the drive gear 4 of the transmission 3 to the front wheel differential gear mechanism 6 via the ring gear 5, and it is possible to provide a differential between the left wheel drive shaft 7a and the right wheel drive shaft 7b of the front wheel drive shaft 7. is transmitted to. The torque transmitted to the differential case 8 of the differential gear mechanism 6 is transmitted to the dynamic horn transmission gear 9, and the direction is changed at right angles by the direction changing gear set 10a of the transformer 710. The torque whose direction has been changed at right angles is transmitted to the propeller shaft 12 via the power transmission unit 11, and is transmitted from the drive pinion 13 to the rear wheel differential gear mechanism 15 via the ring gear 14, and then to the rear wheel drive shaft. The differential is transmitted between the left wheel drive shaft 16a and the right wheel drive shaft 16b.

The power transmission device f11 will be explained with reference to FIG. 2.

Reference numeral 21 denotes a first rotating member connected to the output shaft of the transfer 10, and the first rotating member 21 includes an input horn shaft 22 and a flange portion 23 fixed to the input shaft 22. A second rotating member 24 is disposed on the first rotating member 21 so as to be rotatable relative to the first rotating member 21.
5, and an output shaft 26 which is fixed to the housing part 25 and connected to the propeller shirt 12. The input shaft 22 of the first rotating member 21 and the output shaft 26 of the second rotating member 24 are located on the path-axis line.

A working chamber 27 is defined by the first rotating member 21 and the second rotating member 24, and a first resistor 28 is provided in the working chamber 27.
and a second resistance section 29 are housed. That is, a plurality of substantially cylindrical first resistance portions 28 are attached to the seven flange portions 23 so as to overlap in the radial direction. On the other hand, a plurality of substantially cylindrical second resistance portions 29 are provided on the inner wall of the housing 25 opposing the flange portion 23 so as to overlap in the radial direction. The first resistance section 28 and the second resistance section 2
9 are opposed to each other and extend in the direction of the relative rotation center line (the center line of the input shaft 22 and the output shaft 26).

Since the extension length of the first resistance part 28 is longer than the extension length of the second resistance part 29, the first resistance part The portions 28 and the second resistance portions 29 are arranged in an alternating manner, and on the other side (right side in FIG. 2) C, the first resistance portions 28 and the second resistance portions 29 do not overlap.

Further, the working chamber 27 is filled with magnetic fluid as a working fluid. The magnetic fluid is a solid-liquid multiphase fluid in which fine particles of magnetite (Fe3st) with a diameter of 10-8 m are dispersed in a silicone oil solvent.

Here, electromagnets 30, 31 are arranged near one side and near the other side of the working chamber 27, and these electromagnets 30, 31
are respectively held in holders 32 and 33 made of magnetic material. Note that a sealing member 34 is interposed between the housing 25 and the input shaft 22 to stop l+1 magnetic fluid.

Next, the operation will be explained. 1. When the vehicle travels straight on a paved road, the torque of the engine 1 is transmitted from the transmission 3 to the front wheel drive shaft 7 and the transfer 10. Since the horn transmission device 111 is installed, almost no torque is transmitted to the propeller shaft 12 side, and the vehicle runs as a front-wheel drive vehicle.

At this time, the first rotating member 21 and the second rotating member 24 of the power transmission device 11 rotate simultaneously.

Next, when the front wheels slip when the vehicle is traveling on a rough road with a small coefficient of road friction, the front wheel drive shaft 7 is directly driven by the engine, but since the front wheels have less resistance, the transmission is transmitted to the front wheels. Only a small amount of torque is exerted. Here, the engine side rotation speed of the rear wheel (front wheel drive shaft 7)
Since it rotates less, the second rotating member 24 connected to the rear wheel drive shaft 16 rotates less than the first rotating member 21 connected to the front wheel drive shaft 7 . For this reason, the front wheel drive shaft 7
A difference in rotation occurs between the rear wheel drive shaft 16 and the first rotating member 21 and the second rotating member 24, and the first resistive portion 28 and the second resistive portion 29 rotate relative to each other, and the magnetic Shear the fluid.

At this time, when an exciting current is applied to the electromagnet 30, the magnetic force of the electromagnet 30 draws the magnetic fluid toward one side of the working chamber 27, as shown in FIG.

Therefore, substantially all of the magnetic fluid filled in the working chamber 27 is sheared by the first resistance section 28 and the second resistance section 29. Therefore, the shear force of the magnetic fluid becomes large immediately, and this large shear horn can be quickly transmitted as torque from the rear wheel drive shaft 16 to the rear wheels. That is, the responsiveness of torque transmission to the rear wheels can be improved.

As a result, the rear wheels push the vehicle out, allowing the front wheels to quickly escape from the slipping situation.

Next, during low-speed large steering such as when parking the vehicle, a rotational speed difference occurs between the front wheel drive shaft 7 and the rear wheel drive shaft 16, so this rotational speed difference is absorbed by the power transmission device. So, this time electromagnet 3
When an excitation current is applied to the first resistor 2, the magnetic fluid is attracted to the other side of the working chamber 27.
8 and the second resistance section 29 are drawn to the side where they do not overlap. Therefore, the first resistance section 28 and the second resistance section 29 smoothly rotate relative to each other without being subjected to much shear resistance of the magnetic fluid. Therefore, the rotational speed difference is absorbed by the power transmission device, and tight corner braking can be completely prevented.

By the way, by simultaneously passing excitation current through the electromagnets 30 and 31 and changing the strength of the current flowing through the electromagnet 30 and the current flowing through the electromagnet 31, the magnetic fluid flows in the working chamber 27 from one side to the other. You can move the range. Therefore, the shear resistance of the magnetic fluid sheared by the first resistance section 28 and the two second resistance sections changes, and the characteristics of the torque transmitted to the rear wheel can be changed. As a result, the vehicle can run stably on the road by adjusting the torque characteristics according to road conditions and driving conditions.

FIG. 3 shows the first example used in the first embodiment. Second resistance section 2
Another embodiment of 8.29 is shown, in which both the resistance parts 28 and 29 have the same extension length, but
Elongated holes 28a and 29a provided in both resistance parts 28 and 29
is formed to be shifted to one side in the axial direction (left side in the drawing). Even if formed in this way, the first resistance part 28 and the second
The same operation and effect as when the extension length of the resistance part 29 is changed is achieved, and the magnetic fluid as the working fluid is formed in the elongated hole 28a.

When it is moved to the 29a side, the torque is transmitted thickly.

FIG. 4 shows a second embodiment, in which the same members as in the first embodiment are given the same reference numerals and detailed explanations are omitted. The flange portion 23 that integrally supports the first resistor 11128 is engaged with the input shaft so as to be movable in the axial direction at the engaging portion 41 so as not to rotate with respect to the rotational direction. 7. A spring 40 is interposed on the back surface of the flange portion 23 (opposite to the side where the first resistance portion is provided), and constantly pushes the flange portion to the left side in FIG. In this case, at least the flange portion 23 is made of a magnetic material, and the working fluid is a highly viscous fluid such as silicone oil.

The effect is that when the excitation current of the electromagnet 31 is cut off when driving on a rough road with a small coefficient of friction, the first resistance section 28
is suppressed and moved to the left by the spring 40, and the amount of overlap with the second resistance portion 29 increases. For this reason, power transmission @
The torque transmitted through the gearbox 11 becomes larger, allowing rapid travel even on rough roads. Moreover, the power transmission device 11
When you do not want to increase the torque transmitted through the electromagnet 31, when an excitation current is passed through the electromagnet 31, the 7 flange portion 23 is pulled by the electromagnet 31, and the first resistance portion 28 and the second resistance portion 23 are pulled.
The amount of overlap with the resistance portion 29 is reduced, so that only a small torque is transmitted, and tight corner braking phenomena, etc., are prevented.

[Effects of the Invention] As explained above, according to the present invention, the working fluid is a magnetic fluid, and this magnetic fluid is drawn to one side or the other side of the working chamber by magnetic force, so that this power transmission is improved. When the device is installed in the power transmission line of a four-wheel drive vehicle, a large torque can be quickly transmitted to the wheel with a higher coefficient of friction. That is, it is possible to improve the responsiveness of torque transmission to wheels with a high friction coefficient and the amount of transmitted torque. As a result, it is possible to quickly get the vehicle out of a slipping state.

Furthermore, it is possible to completely prevent the occurrence of tight corner braking during low-speed large steering such as when parking the vehicle.

[Brief explanation of the drawing]

1 and 2 are diagrams showing a first embodiment of a power transmission device according to the present invention, and FIG. 1 is a schematic diagram showing the entire structure of this power transmission device interposed in a power transmission path of a four-wheel drive vehicle. Figure, 2nd
The figure is a schematic sectional view of this power transmission device, FIG. 3 is a perspective view showing another embodiment of the first and second resistance parts used in the first embodiment, and FIG. 4 is a schematic sectional view of the second embodiment. FIG. 5 is a sectional view showing a conventional power transmission device. 21...First rotating member 24...Second rotating member 27...Working chamber 28...First resistance part 29...Second resistance part 30.31...Electromagnet agent Patent attorney 3 Yoshi Yasuo figure 5

Claims (2)

[Claims] (1) A first rotating member and a second rotating member that are arranged so as to be relatively rotatable, and fixedly attached to each of the first rotating member and the second rotating member and extending in the direction of the center line of the relative rotation and arranged alternately. A power transmission device including a first resistance part and a second resistance part overlapping each other, and a working chamber filled with a working fluid that is sheared by the first resistance part and the second resistance part. A power transmission device characterized in that, as a fluid, this magnetic fluid is drawn to one side or the other side of a working chamber by magnetic force. (2) A first rotating member and a second rotating member that are arranged to be relatively rotatable, and fixedly installed on each of the first rotating member and the second rotating member and extending in the direction of the relative rotation center line and alternately A power transmission device comprising: a first resistance section and a second resistance section that overlap with each other; and a working chamber filled with a working fluid that is sheared by the first resistance section and the second resistance section. 1. A power transmission device characterized by being provided with a magnet that is capable of changing an overlapping length between the second resistance portion and the second resistance portion, and that changes the overlapping length using magnetic force.