JPH03103624A - Viscous coupling - Google Patents

Abstract

PURPOSE:To change characteristics with a small stroke by placing a plurality of clutch cylinders (circular cylinders) alternately along a diameter direction, providing a means for changing an overlap of the cylinders and forming recesses and protrusions on the cylinders in the axial directions. CONSTITUTION:A viscous coupling 13 has a relatively rotatable input shaft 31 and an output shaft 33, the latter of which can be slid right and left. Flanges 39, 41 are formed with the respective shafts 31, 33, a plurality of cylinders 43, 45 are alternately fixed along the diameters of the respective flanges 39, 41, and the cylinders 43, 35 are provided with recesses 47, 49 and protrusions 51, 53. When the input shaft 31 is driven, a torque is transmitted to the cylinder 45 with shearing force of silicon oil. when difference in rotations between both shafts 31, 33 is large, the difference in rotations is limited to permit a large torque to be transmitted, while when the difference in rotations is small, the difference is allowed to make the transmission torque small. When the output shaft 33 is moved toward the right, an overlap of the cylinders 43, 45 is reduced to have the transmission torque and differential limiting force reduced so that characteristics can be adjusted by changing slightly relative positions of the respective cylinders.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) This invention relates to a viscous coupling that transmits torque via viscous fluid.

(Prior art) A ``viscous clutch'' is described in JP-A-62-106130.This device has a sleeve disposed within a housing so as to be relatively rotatable and axially movable, and a viscous clutch is disposed within the housing. A plurality of cylinders filled with a high fluid and arranged alternately in the radial direction inside the housing are separately fixed to the housing and the sleeve, and the human torque from one side of the housing and sleeve is transferred to the other due to the shear resistance of the fluid. At the same time, the housing and sleeve are moved relative to each other in the axial direction by operating means to change the overlapping margin of the cylinders, thereby adjusting torque transmission characteristics, differential limiting characteristics, etc.

(Problems to be Solved by the Invention) However, in this structure, the changes in each characteristic with respect to the stroke of relative movement are relatively small, and therefore a large movement stroke is required to adjust the characteristics. Furthermore, since the movement resistance is large due to the viscosity of the fluid, the response when trying to adjust the characteristics is poor, and as a result, the power of the operating means must be increased.

Therefore, the object of the present invention is to provide a viscous force coupling whose characteristics can be greatly changed with a small stroke.

[Structure of the invention]

(Means for Solving the Problems) The viscous coupling of the present invention includes a pair of transmission members arranged to be relatively rotatable and relatively movable in the axial direction, a working chamber filled with viscous fluid, and a diameter inside the working chamber. A plurality of clutch cylinders are arranged alternately in the direction and individually engaged with the transmission member, and an operating means for operating the transmission member to move relatively in the axial direction to change the overlapping margin of the clutch cylinders, It is characterized by having a concave portion and a convex portion.

(Operation) Torque input from one transmission member is transferred between the clutch cylinders due to the shear resistance of the viscous fluid, and is transmitted to the other transmission member. When the rotational difference between the transmission members is large, this rotational difference is limited and a large torque is transmitted, and when the rotational difference is small, this rotational difference is allowed and the transmitted torque is small.

By relatively moving the transmission member in the axial direction using the operating means and changing the overlapping margin of the clutch cylinders, the shear resistance value changes and the torque transmission characteristics and differential limiting characteristics can be adjusted. In this process, each characteristic changes greatly between the position where one convex part and the other concave part face each other and the position where both concave parts and convex parts face each other (described later), so a small stroke is necessary. A characteristic change can be obtained, and the response is also good.

(Embodiment) One embodiment and other aspects will be explained with reference to FIGS. 1 to 5. Figure 4 shows four-wheel drive (4WD) using this embodiment.
Shows the car's power system. Hereinafter, the left and right directions are the left and right directions in Figure 1, and the left side is the front of this vehicle (the upper part of Figure 4).
corresponds to Note that members not numbered are not illustrated.

First, the configuration of the power system of this vehicle will be explained with reference to FIG. This power system consists of engine 1, transmission 3,
Front differential 5 (differential device on the front wheel side), front axles 7, 8, left and right front wheels 910, transfer 11, viscous coupling 13 of this embodiment, propeller shaft 15, rear differential 17 (differential device on the rear wheel side), rear It consists of axles 19, 21, left and right rear wheels 23, 25, and the like.

The viscous coupling 13 has a housing 29 and an input shaft 31 (transmission member) and an output shaft 33 (transmission member) arranged so as to be relatively rotatable inside the housing 29. The human power shaft 31 is connected to the drive shaft 35 of the transfer 11. The connected output shaft 33 is connected to the propeller shaft 15 side via a slide joint. This output shaft 33 can be slid left and right by an actuator (operating means) as shown by the arrow in FIG. 1 <a).

An X-ring 36.36 (sealing member having an X-shaped cross section) is disposed between the two housings and the human output shaft 31.33, and forms a liquid-tight working chamber 37 inside the housing 29. This working chamber 37 is filled with highly viscous silicone oil (viscous fluid).

Inside the working chamber 37, each shaft 31, 3B is formed with a flange portion 39.41, and each flange portion 39.41 has a plurality of cylinders 43.45 (clutch cylinders) arranged alternately in the radial direction. It is fixed separately. Each cylinder 43.45
As shown in FIG. 1(a), recesses 47, 49 and convex portions 51, 53 with round peaks and valleys and equal pitches are provided in the axial direction, and as shown in FIG. 1(b), ,
55.57 in the axial direction is provided. In this way, the viscous coupling 13 is constructed.

Therefore, when the input shaft 31 is rotationally driven by the drive force from the engine 1 via the transmission 3, the differential case 58 of the front differential 5, and the transfer 11, the input shaft 31 is rotating ahead of the output shaft 33. Input shaft 31
The rotation is transmitted from the cylinder 43 to the cylinder 45 by the shear resistance of the silicone oil, which rotates the output shaft 33 and rotates the rear wheel 23.
．． 25 side. At this time, if the rotation difference between the respective shafts 31 and 33 is large, this rotation difference is limited and a large torque is transmitted, and if the rotation difference is small, this rotation difference is allowed and the transmitted torque is small. When the output shaft is moved to the right by the actuator as shown in the lower half of Fig. 1 (a), the cylinder 43.4
The overlapping margin e of 5 is reduced, and the transmitted torque and differential limiting force are reduced. The actuator is configured to be automatically operated according to steering conditions and road surface conditions.

Each recess 47 of each cylinder 43, 45 while changing the overlapping allowance e,
The transmitted torque changes as described below depending on the relative position between the convex portion 49 and each convex portion 51,53. This will be explained with reference to FIGS. 2 and 3.

As shown in FIG. 2, each cylinder 59.61 has a rectangular recess 63.6.
Consider the case where 5 and convex portions 67 and 69 are provided.

Here, the meaning of each symbol is as follows.

In addition, in the figure (a), the concave portion 63 is opposed to the convex portion 69,
shows the relative position I where the four parts 63 and 65 face each other, and the relative position I where the four parts 63 and 65 face each other, and the relative position II where the four parts 67 and 69 face each other.

k, a: constant, η: filling rate, e: overlap margin, ρ: specific gravity,
ν: dynamic viscosity coefficient, ω: differential angular velocity, α: convex portion 67.69
height, λ; the sum of the distance between the opposing convex portions 67.69 and α, the torque is M+ -2x (r -AS7-!-) x Xl) ν
(tl4X (r+) 21” k+2r (r −
10) x xρνω4X (r − ) ' n” k
−mη”kxlpνω”, l (r −A−T−)
(r+)' + (r-10) (r-) 2
In equation 1 (1), the first equation on the right side is the convex portion 69 of the cylinder 6l.
The second equation on the right side is M2 -2r of the cylinder 61.
(r-"') X'Xρνω on r'rl" k2
2 λ−α +2r (r −Ai−!!−) xAxpνωenginer2
η" k2 2 λ+a - η"kr! ! ρνωr2t (r −”') (±)
+ (r−”−’) (±)2 λ−α
2 λ ten α2λ −n” ktlpνωr2 (Y:7r−1)
- (2) In equation (2), the first equation on the right side is the torque of the six convex parts of the cylinder 61, and the second equation on the right side is the torque of the six convex parts of the cylinder 61.
This is the torque of the recess 65 of No. 1.

Here, kinematic viscosity, differential rotation speed, filling rate, other constants, etc. are 1
Assuming that and ■ are equal, and subtracting formula (1) from formula (2), considering only the formula in brackets, we get 2λ 3 d ``TS♂1 r2-2 1 (r+7) + (r-7) } +Wol (r+2) +(r1F) 1Here, λ, ``>0, λ>a, and r>α, so “. (2)-(1)>0 Therefore, the torque at the relative position ■ is greater than the torque at the relative position I.

FIG. 3 shows another cylinder 79.81 with a different shape of four parts 71.73 and a convex part 75.77. (b) The figure is (a)
As drawn with broken lines in the figure, this is the relative position I where the recess 71 and the projection 77 face each other, and the recess 73 and the projection 75 face each other, and (e
) The figure shows that the recess 71.7 is drawn as a solid line in figure (a).
Relative position where 3 and convex parts 75 and 77 face each other■
It is.

Similar to the example in Fig. 2, the distance between the opposing convex portions 75 and 77 is λ
- α, the distance between the convex portion 75 and the concave portion 73, and the distance between the convex portion 77 and the concave portion 71 are λ, and the torque at the relative position ■ is larger than the torque at the relative position ■. Furthermore, by changing the length L of each convex portion 75, 77, various relationships between the torque transmission characteristic and the differential limiting characteristic with respect to stroke changes can be set.

In this way, each characteristic changes by changing the relative position of each cylinder by the length of the concave and convex portion, so when adjusting the characteristics within that range, the movement stroke is very small, and the response is therefore good. . Further, in this embodiment, the provision of the axial grooves 55 and 57 improves the flow of silicone oil and reduces the movement resistance of the output shaft 33, further improving the response and thus allowing the actuator to be made smaller. Furthermore, since the rigidity of each cylinder is improved by providing the unevenness in the examples shown in FIGS. 1 and 3, the cylinder can be made thinner and lighter.

Next, the function of the viscous coupling 13 will be explained based on the performance of the vehicle shown in FIG.

The driving force of the engine 1 is shifted by the transmission 3 and transmitted to the front wheels 9 and 10 by the front differential 5, and is also transmitted to the rear defer via the transfer 11, viscous coupling 13, and propeller shaft 15, and is transmitted to the rear wheels 23 by the rear differential 17. 25.

In a state where there is no difference in rotation between the front and rear wheels, such as when driving on a good road, no driving force is transmitted from the viscous coupling 13 to the rear wheels 23, 25, and the vehicle enters a two-wheel drive state. Further, when the front wheels 9.10 slip on a rough road, the driving force is transmitted to the rear wheels 23.25 via the viscous coupling 13, and the vehicle enters a 4WD state, improving its ability to travel on rough roads. When parking the vehicle or making a U-turn, the difference in rotation between the front and rear wheels is small and absorbed by the viscous coupling 13, so tight corner braking does not occur.

If the overlap e of the cylinder 43.45 of the viscous coupling 13 is made small, the rear wheel will become 23.25 mm for a certain rotational difference.
The driving force sent to the side becomes smaller, and the vehicle becomes substantially in a two-wheel drive state. When the overlap e is increased, the rear wheel 23.
The driving force transmitted to the 25 side is increased, further improving the running performance on rough roads. In addition, since characteristics such as transmission torque and differential limiting force can be changed with a small stroke, the response of characteristic adjustment is extremely good for preventing tight corner braking or escaping from rough roads.

Note that the shape of the unevenness of the cylinder is arbitrary;
In addition to the example shown in FIG. 3, for example, as shown in FIG.
Alternatively, a triangular concave portion 91 and a triangular convex portion 93 formed by processing and forming a thin cylinder 89 as shown in FIG.

〔Effect of the invention〕

As described above, in the viscous coupling of the present invention, since the cylinder is provided with unevenness in the axial direction, the characteristics can be changed with a small stroke, and the response in adjusting the characteristics is good.

[Brief explanation of drawings]

FIG. 1(a) is a sectional view of one embodiment, and FIG. 1(b) is A of FIG.
-A sectional view, Figure 2 shows the second aspect of the clutch cylinder (
a) and (b) are longitudinal sectional views of the relative positions ■ and ■, respectively, FIG. 3(a) is a longitudinal sectional view showing the third aspect, (1)) and (
c) is a longitudinal cross-sectional view at relative positions I and H, respectively, FIG. 4 is a skeleton mechanism diagram showing the power system of a vehicle using the embodiment of FIG. 1, and FIGS. 4th and 5th
FIG. 31... Input shaft (transmission member) 33... Output shaft (transmission member) 37... Working chamber 43, 45, 59, 61, 79, 81. 83, 89...
・Cylinder (clutch cylinder) 47, 49.63, 65. 91... Concavity 51.53, 67, 69. 93... Convex portion 71. 73, 85, 75. 77. 87,

Claims (1)

[Claims] A pair of transmission members arranged to be relatively rotatable and relatively movable in the axial direction, a working chamber filled with viscous fluid, and a plurality of clutches arranged alternately in the radial direction within the working chamber and individually engaged with the transmission members. A viscous coupling comprising a cylinder and an operating means for operating a transmission member to move relative to each other in the axial direction to change the overlapping margin of the clutch cylinders, and each clutch cylinder is provided with a concave portion and a convex portion in the axial direction. .