JPH0257729A - Power transmission - Google Patents

Abstract

PURPOSE:To miniaturize the captioned device by providing a slit to one or both of wall surfaces facing to each other of cylinders and forming the slit in such a manner that the open-area becomes gradually larger as the position comes near the free end of the cylinder. CONSTITUTION:When a housing 31 is rotated by the driving power from an engine, the rotation of the housing 31 is transmitted from a cylinder 45 to a cylinder 47 by the shearing resistance of silicone oil and outputted from a rotary member 35. At this time, if the difference in the number of revolutions between the housing 35 and the rotary member 35 increases, both limiting quantity of this differential rotation and transmitting torque increase, while if the difference decreases both limiting quantity and transmitting torque decrease. Therefore, by moving the rotary member 35 through the operation of a shift fork 57 so as to change the overlapped quantity of the cylinders 45 and 47, the torque transmitting characteristics can be changed. At this time, owing to wedge-shaped slits 49, which are formed in the cylinder 45 on the housing (31) side, as the overlapping quantity L between the cylinder 45 and the cylinder 47 increases the effective operational area increases sharply. In other words, for the same stroke the adjustable range of the characteristics can be widened, compared with the conventional method.

Description

DETAILED DESCRIPTION OF THE INVENTION (Objective of the Invention) (Industrial Application Field) The present invention relates to a power transmission device used in, for example, a vehicle.

(Prior Art) A viscous clutch is described in JP-A-62-106130. In this device, a pair of rotating members are arranged so as to be relatively rotatable on the same axis and movable relative to each other in the axial direction, and a plurality of cylinders having different diameters and arranged alternately on the same axis are individually fixed to the rotating members. , these cylinders are filled with viscous fluid, and when differential rotation occurs between the rotating members, torque is transmitted from one side to the user due to the shear resistance of the viscous fluid, and the rotating members are moved relative to each other. This is a viscous coupling configured so that differential rotation control (limitation and allowance) and torque transmission characteristics can be adjusted by increasing or decreasing the overlapping margin of the cylinders.

In this device, if the cylinder has a normal shape, the amount of change in characteristics will be small in the stroke ratio of relative movement, and therefore, in order to obtain a sufficient adjustment range of characteristics, it is necessary to operate the stroke largely, which increases the size of the device. Therefore, it is not possible to quickly adjust the characteristics. Moreover, due to the structure of this device, one end of the cylinder cannot be supported and must be left free.

Therefore, increasing the length of the cylinder is disadvantageous in terms of support strength.

(Problems to be Solved by the Invention) Therefore, an object of the present invention is to provide a power transmission device that has a short stroke when adjusting characteristics, has a large supporting strength of members, and can be downsized.

[Structure of the invention]

(Means for Solving the Problems) A power transmission device of the present invention includes a housing and a rotating member passing through the housing, which are arranged so as to be relatively rotatable and relatively movable in the axial direction, and have different diameters inside the housing. A plurality of cylinders arranged alternately on the same axis are separately provided on the housing and the rotating member, a viscous fluid is sealed in the housing, and a cutout 1n is provided on one or both of the opposing wall surfaces of the cylinder, and , is characterized in that the opening area of the cylinder increases gradually toward the open end of the cylinder.

(Function) When torque is input from either the housing or the rotating member, the torque is transmitted from the cylinder on one side to the cylinder on the other side due to the shear resistance of the viscous fluid, and the torque is output from the other cylinder. At this time, as the rotation difference between the input and output increases due to the balance between the input torque and the drive resistance on the output side, the limit amount of this differential rotation increases and the transmitted torque increases, and the rotation difference becomes smaller. The fill limit decreases and the transmitted torque decreases.

If the effective operating area is increased or decreased by changing the overlapping margin of the cylinders through relative axial movement between the housing and the rotating member, the area for transmitting and receiving torque due to the shear resistance of the viscous fluid will change, so differential rotation control 1 m and torque transmission characteristics can be changed. In addition, since the cylinder is provided with a defective portion whose opening area gradually increases toward its open end, the effective operating area of the cylinder changes greatly with a small stroke, making it possible to quickly adjust the characteristics over a wide range. Therefore, since the cylinder can be shortened, it is advantageous in terms of supporting strength and the device can be made smaller.

(Example) An example will be described with reference to FIGS. 1 to 5. FIG. 5 shows an example in which this embodiment is applied to a power transmission system having a width of 1J (4WD). In the following description, the left and right directions are the left and right directions in FIGS. 1 and 2, and the left side of these figures corresponds to the front of the vehicle in FIG. 5.

First, the power transmission of this vehicle will be explained with reference to FIG.

The driving force of the engine 1 is changed in speed by a transmission 3 and transmitted to a transfer 5. The transfer 5 transmits the transmitted driving force to the front differential 7 (differential device on the front wheel side) and also to the rear differential 13 (differential device on the rear wheel side) via the WeJ power transmission device 9 of this embodiment and the propeller shaft 11. (differential device). The transmitted driving force is transferred to the front axle 15 by the front differential 7.
17 to the left and right front wheels 19.21, and the rear differential 13 distributes the power to the left and right rear wheels 27 via the axle 23.25.
．． It will be distributed to 29 people.

Next, the configuration of the embodiment will be explained with reference to FIGS. 1 and 2.

The housing 31 is connected to the rear end of an input shaft 33 connected to the output side of the transfer 5, and rotates by inputting the driving force from the engine 1. The rotating member 35 consists of an output shaft 37 passing through the housing 31 and a flange 39 connected to the front end of the output shaft 37 inside the housing 31. An X-ring 41 is arranged to keep the housing 31 liquid-tight. In this way, the housing 31 and the rotating member 35 are configured to be relatively rotatable and relatively movable in the axial direction.

Inside the housing 31, a plurality of thin cylinders 45 having mutually different diameters are coaxially arranged and fixed to the left side wall 43 of the housing 31.

Further, on the left side surface of the flange 39, a plurality of thin-walled cylinders 47 are arranged coaxially with the cylinder 45 and alternately, and have mutually different diameters.
is fixed. These cylinders 45 and 47 are fixed at one end by engaging concentric circular grooves provided in the housing 31 and the seven flange 39, respectively, or by welding or the like.

On the right end side of the cylinder 45 on the housing 31 side, as shown in FIG. has a narrow horizontal shape. The flange 39 is provided with a large number of through holes 51, and the housing 31 is filled with high viscosity silicone oil.

The output shaft 37 of the rotating member 35 is connected to the propeller shaft 11 via a slip joint (not shown) so as to be movable in the axial direction. A ring 53 is fixed to the output shaft 37, and a shift fork 57 is slidably engaged with an outer circumference ll[I55 provided on the ring 53. Therefore, if the shift fork 57 is moved left and right in the axial direction, the rotating member 35 is moved left and right.

This movement changes the overlap of the cylinders 45 and 47. L changes from L Ll + ax, which is slightly shorter than the shorter length of the cylinder 45.47, to 1 sin, where the cylinder 45.47 is slightly shaped, and Ω - Lwax - L
Min is the stroke O of the rotating member 35 due to overlap adjustment.
- It becomes. At this time, the through hole 51 becomes a flow path for silicone oil and facilitates movement of the rotating member 35.

The above-described operation of the shift fork 57 can be performed manually from the driver's seat or automatically according to driving conditions, road surface conditions, and the like.

Next, the functions of this embodiment will be explained.

When the housing 31 rotates due to the driving force from the engine 1, this rotation is prevented by the shear resistance of the silicone oil.
5 to the cylinder 47 and output from the rotating member 35. At this time, when the rotational difference between the housing 31 and the rotating member 35 increases, the differential rotation limit and the transmitted torque increase, and when the rotational difference decreases, the differential rotation limit and the transmitted torque decrease.

By operating the shift fork 57 to move the rotating member 35 and changing the overlap of the cylinders 45, 47, the torque transmission characteristics can be changed between the song taa and the song 1b, as shown in FIG. That is, for example, if such an operation is performed when the rotational difference N is n, the transmitted torque can be adjusted from the maximum tna to the minimum tnb. Further, the limit amount of differential rotation is maximum on curve a and minimum on curve a. Also, when the curve a has an overlap of 1 max, the curve a is L
These are the characteristics obtained when sin.

As described above, as the amount of overlap between the wedge-shaped slit 49 provided in the cylinder 45 on the housing 31 side and the cylinder 47 increases, the effective operating area increases rapidly. Therefore,
As shown in FIG. 4, when the rotational difference N is constant, the operating stroke to obtain the required transmission torque tnItn2 is 92, which is shorter than Ω in the conventional example. (This means that if the stroke is kept the same, the adjustment range of characteristics can be made wider in the embodiment than in the conventional example.) For this reason, the cylinders 45 and 47 can be made shorter.
The device 9 can be made smaller, and the operating stroke can be shortened, allowing quick torque adjustment. Further, for the cylinders 45 and 47 whose release side must be the free end, the overall length is short, the release side is lightweight, and the support strength is increased if the number of defects on the support side is reduced, which is advantageous.

Next, functions corresponding to the performance of the vehicle shown in FIG. 5 will be explained.

In this vehicle, the front wheels 19 and 21 are directly connected and driven by the driving force from the engine 1, and the rear wheels 27 and 29 are driven via the device 9, so the rotation difference between the front and rear wheels is
This is the rotation difference between the input and output.

Therefore, the driving force corresponding to this rotational difference is transmitted to the rear wheels 27 and 29, the driving force distribution ratio between the front and rear wheels is determined, and the differential rotation limit am is determined. Furthermore, since these torque transmission characteristics and differential rotation control can be changed, the maneuverability, running stability, economic efficiency, etc. of the vehicle are significantly improved.

Here are some examples: On a good road where the frictional resistance on the road surface is large and its changes are small, the rotational difference is small, so the torque distributed to the rear wheels 27° and 29 is small. Therefore, the vehicle has two-wheel drive (
The driving force distribution state is close to that of the 2WD) state, resulting in improved fuel efficiency. At this point, if the shift fork 57 is operated to increase the overlapping displacement of the device 9, even in such a small rotation difference state, the drive force distribution to the rear wheels 27.29 side will be increased, and the vehicle will be 4 Vl.
state. Therefore, the driving force of the engine 1 is distributed to all four wheels, increasing the margin of grip force in each wheel, making it difficult to slip, and improving running stability.

When the front wheels 19.21 slip on rough roads, the rotational difference increases, so a large amount of driving force is distributed to the rear wheels 27.29 through the device 9, and this driving force improves running performance and ability to escape from rough roads. do. At this time, if the overlap of the device 9 is increased, the proportion of driving force distributed to the rear wheels 27 and 29 increases, and the running performance and 11 (two-way performance) are further improved.

During sudden acceleration, if slip occurs on the front wheels 19.21 side and acceleration performance decreases, driving force is distributed to the rear wheels 27.29 due to the rotational difference caused by this front wheel slip.

Since the driving force is thus distributed to the rear wheels 27 and 29, where the load is transferred due to acceleration, not only the decrease is compensated for, but also the acceleration performance is improved. At this time, if the transmission torque of the device 9 is increased, the acceleration performance will be roughly improved.

When cornering, the rotation difference tolerance function of the device 9 absorbs the rotation difference between the front and rear wheels, so that smooth cornering is achieved. By reducing the overlap of the device 9 and increasing the tolerance function for rotational differences, turning performance can be improved and smooth cornering can be performed even when cornering with a small turning radius. Furthermore, even when making a sharp turn at low speed, such as when parking the vehicle, the torsion of the propeller shaft 11 is absorbed by the mounting @9, so tight corner braking does not occur.

Note that the shape of the slit 49 is not limited to the tree shape described above. The shape of the sides of the slit may be other than straight as long as it is wide at the opening and gradually narrows toward the top. Figure 6 shows some examples. The slit 59 shown in FIG. 5A has curved sides. In this case, the curve may be convex outward or convex inward, and the slit 61 shown in FIG. 6(b) has stepped sides. Further, in the above example, the slits are formed symmetrically with respect to the generatrix of the cylinder, but they may be inclined with respect to the generatrix 65, as in the case of the slit 63 in FIG. 6(C). The direction of this inclination may be either left or right with respect to the generatrix 65.

Further, as the defective portion, a through hole may be provided in addition to such a slit. An example is shown in FIG.

In the same figure (a), various sizes of opening areas are given to the through hole 67,
This is an example in which the cylinder with the largest area is placed on the open side of the cylinder, and the cylinders with smaller areas are placed in order toward the fixed side. Further, FIG. 6B shows an example in which the arrangement density of the through holes 69 having the same opening area is gradually decreased from dense to sparse from the open side to the fixed side of the cylinder. Note that the shape of the through holes 67 and 69 is not limited to a circle.

The cutout portion may be provided in either the cylinder on the housing side or the cylinder on the rotating member side as in the above embodiment, or may be provided on both. Moreover, it may be provided on all of one or both cylinders, or may be provided on some, for example every other cylinder.

Furthermore, the shape of the defective portion of each cylinder may be freely selected from the above-mentioned slits and through-holes, or any combination thereof. Alternatively, they may be combined on the same cylinder. FIG. 7(C) shows an example in which a slit 49 and a through hole 69 are combined.

〔Effect of the invention〕

As described above, the power transmission device of the present invention can transmit a small torque while controlling differential rotation, and can also change these characteristics arbitrarily and quickly. In addition, it is possible to downsize the cylinder, and the support strength of the cylinder is high.

[Brief explanation of the drawing]

Fig. 1 is a schematic sectional view showing the configuration of one embodiment, Fig. 2 is a sectional view of the cylinder of this embodiment, Fig. 3 is a graph showing the characteristics of this embodiment, and Fig. 4 is a diagram showing the actual tM example. A graph comparing the characteristics of the conventional example, Fig. 5 is a schematic diagram showing the power transmission of a vehicle using this embodiment, and Figs. 6 and 7 are respective external views showing various aspects of the defective part of the cylinder. It is. 31...Housing 35...Rotating member 45.4
7...Cylinder 49.59.61.63...Slit (missing part) 67
．． 69...Shell opening (missing part) 31...Housing 35...Rotating member 45° 47...Cylinder 49.59.61.63...Slit (missing 1! II
)67.69...Through hole (missing part) Fig. 3 Fig. 4 Fig. 1 Fig. 14'+ Fig. 2 Fig. 5 b Fig. 7 (a) Fig. 7 (b) Fig. 7 (C )

Claims (1)

[Claims] A housing and a rotating member passing through the housing are arranged to be relatively rotatable and relatively movable in the axial direction, and inside the housing, a plurality of cylinders having different diameters coaxially and alternately arranged in the radial direction are connected to the housing and the rotating member. and a viscous fluid is sealed in the housing, and a cutout is provided on one or both of the opposing wall surfaces of the cylinder, and the opening area is formed to increase sequentially toward the open end of the cylinder. A power transmission device characterized by: