JPH0335529B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a power transmission device.

[Prior Art] In general, a differential device for a vehicle has a function of absorbing the rotational difference, that is, the differential, that occurs between the two drive shafts of the vehicle when the vehicle is rotated, and provides smooth drive running. In some cases, it may interfere with driving.

For example, if one wheel falls into the mud and slips, the driving force will not be transmitted to the other wheel due to its structure, making it impossible to escape from the mud. In order to avoid such a situation, a differential limiting device is designed to limit the differential rotation when a certain amount of differential rotation occurs between the two drive shafts.

This differential control device includes one such as that disclosed in Japanese Patent Application Laid-open No. 77530/1983, in which a sealed chamber of the differential limiting device is filled with viscous fluid. In the sealed chamber filled with viscous fluid, there are provided a rotary plate that extends to one transmission shaft side through the sealed chamber, and a rotary plate that faces the rotary plate and continues to the other transmission shaft side.

[Problems to be Solved by the Invention] In such a differential limiting device, for example, when one wheel falls into the mud and starts idling, each rotary plate causes relative rotation, but at this time, resistance due to viscous fluid acts. This is why a differential rotation limiting function is exerted between both output shafts.

However, the temperature of the viscous fluid increases due to the heat generated during relative rotation of the rotating plates. As a result, the internal pressure within the sealed chamber increases. In this case, if the relative rotation of each rotating plate continues, the internal pressure in the sealed chamber will reach a maximum, and there is a risk that the sealing member etc. will eventually be damaged.

For this reason, in order to prevent the internal pressure in the closed chamber from increasing, a means has been proposed for preventing relative rotation of the rotary plates by means of fastening means, as seen in Japanese Patent Publication No. 58-48779, for example. This means requires a fastening means that operates when the internal pressure rises, resulting in a complicated structure and is also undesirable from a cost standpoint.

Therefore, this invention has a simple structure, and
It is an object of the present invention to provide a power transmission device capable of suppressing relative rotation of rotating plates when the internal pressure in a closed chamber increases.

[Means for Solving the Problems] In order to achieve the above object, in the present invention, a rotatable sealed chamber filled with viscous fluid is formed, and one side is supplied to the sealed chamber through the sealed chamber. In a power transmission device, the outer peripheral wall of the sealed chamber is elastically deformed due to an increase in internal pressure. At times, it is brought into contact with the inner circumferential wall of the case to generate frictional torque.

[Operation] In such a power transmission device, for example, when one wheel idles, each rotating plate undergoes relative rotation against the resistance of the viscous fluid. At this time, a differential rotation limiting function is exerted between both output shafts due to the resistance caused by the viscous fluid.

Next, when the relative rotation of each rotating plate continues against the resistance of the viscous fluid, the temperature of the viscous fluid increases due to the heat generated during the relative rotation, and the internal pressure in the sealed chamber increases. When this internal pressure increases to near the maximum, the sealed chamber expands and becomes elastically deformed. At this time, the sealed chamber comes into contact with the inner circumferential wall of the case, and the frictional torque generated at that time acts as a brake on the rotation of the sealed chamber, eliminating the relative rotation of each rotary plate. This makes it possible to suppress the increase in internal pressure within the closed chamber, and provides reliable power transmission function.

[Embodiment] Hereinafter, an embodiment of the present invention applied to a differential limiting device for a vehicle will be described in detail with reference to the drawings.

In the figure, numeral 1 indicates a differential case that can be rotated by a drive gear (not shown).

A sealed chamber 3 filled with a viscous fluid such as silicone oil is formed on one side of the differential case 1.

The sealed chamber 3 includes a large-diameter sleeve 5 disposed along the inner circumference of the differential case 1, a side plate 7 integrally provided on both sides of the large-diameter sleeve 5, a collared sleeve 9, and a small-diameter stepped sleeve 11. The side plate 7 is rotatably fitted into the small diameter portion of the stepped sleeve 11 in a watertight manner by means of a seal member 13.

Further, the enlarged portion of the stepped sleeve 11 is rotatably attached to the flange sleeve 9 and sealed by a sealing member 15. The other end of the large diameter sleeve 5 is integrally connected to the outer periphery of the flange portion 9a of the flange sleeve 9.

Further, splines 17 and 19 are provided on the small diameter portion of the stepped sleeve 11 and on the inner periphery of the flange sleeve 9. The left and right output shafts W and _W1 are spline-fitted to the splines 17 and 19, respectively.
Each output shaft W, _W1 is connected to a wheel drive shaft (not shown).

Splines 21 and 23 are provided on the inner periphery of the large-diameter sleeve 5 and the outer periphery of the stepped sleeve 11, respectively, which constitute the sealed chamber 3, and rotary plates 25 and 27 are attached to the splines 21 and 23 with small gaps. They are locked in such a way that they alternately face each other. That is, the rotating plate 25 of the plurality of rotating plates 25 and 27 is locked to the large-diameter sleeve 5 side, and the rotating plate 27 is locked to the stepped sleeve 11 side, and the former rotating plate 2 is locked to the stepped sleeve 11 side.
5 rotates together with the left output shaft W. Further, the latter rotary plate 27 is designed to rotate together with the right output shaft _W1 that is locked to the inner periphery of the sleeve 11. A viscous fluid such as the silicone oil is acting on each of these rotary plates 25 and 27.

Furthermore, a braking member 29 made of a material that is wear-resistant and has a large coefficient of friction is provided on the outer periphery of the large diameter sleeve 5 constituting the sealed chamber 3 and the outer periphery of the flange portion 9a of the flange sleeve 9. The braking member 29 is also provided on the differential case 1 side and has a slight gap. Note that instead of the braking member 29, the outer peripheral walls 5, 9a of the sealed chamber 3 and the inner peripheral wall 1a of the differential case 1 may be surface-treated to ensure wear resistance.

On the other hand, a gear portion 31 is formed on the side plate 7 of the sealed chamber 3, and the side plate 7 serves as one differential large gear. That is, a differential pinion 33 that can rotate while revolving together with the differential case 1 is meshed with the gear portion 31 .

The differential small gear 33 is rotatably mounted on a small gear shaft 35 mounted on the differential case 1, and the differential large gear 33 is attached to a separately formed differential large gear 3.
7 are engaged.

Note that the output shaft is located in the shaft hole of the differential gear 37.
W ₁ passes through and is splined.

In the differential limiting device configured in this way, if there is no differential between the left and right output shafts W, W ₁ ,
That is, when traveling straight, the driving rotation of the differential case 1 is driven by the differential small gear 33 that revolves, and the differential large gear 37.
to one output shaft _W1 , and the other to gear part 3
1. It is transmitted to the other output shaft W via the flange sleeve 9 of the sealed chamber 3 at the same speed. Next, when a slip or the like occurs in the wheel on one of the output shafts, the differential pinion 33 rotates, and the rotating plates 25 and 27 undergo relative rotation against the resistance of the viscous fluid, but at this time, Due to the resistance caused by the viscous fluid, a differential limiting action works and driving force is transmitted to both output shafts W and W ₁ .

Next, as the relative rotation of the rotating plates 25 and 27 continues, the temperature of the viscous fluid increases due to the heat generated during the relative rotation. In this case, the internal pressure within the sealed chamber 3 increases and the sealed chamber 3 expands and is elastically deformed. At this time, the large-diameter sleeve 5 and the differential case 1 constituting the sealed chamber 3 are such that the former rotates integrally with the rotating plate 25, and the latter rotates with the pinion shaft 35, the differential pinion 33, the differential large gear 37, and the other. Output shaft W ₁ and stepped sleeve 1
Since it rotates integrally with the rotary plate 27 via the rotary plate 1, there is a relative rotation between the two.
Due to the expansion of
Frictional torque is generated through this, and a braking action is applied to the sealed chamber 3. Therefore, relative rotation of each rotary plate 25, 27 is eliminated. Therefore, an increase in the internal pressure in the sealed chamber 3 is suppressed, the seal member is prevented from being damaged, and a reliable differential limiting action can be obtained by the friction torque.

In this embodiment, a differential limiting device has been explained, but as shown in Fig. 2, in a so-called four-wheel drive type that drives front wheels and rear wheels, the differential limiting device may It can also be easily applied to those provided in

[Effects of the Invention] As explained above, according to the power transmission device of the present invention, when the internal pressure in the sealed chamber increases, the elastic deformation of the sealed chamber causes the outside of the sealed chamber to be pressed against the inner wall of the case. Since the relative rotation of each rotary plate is suppressed, the structure can be the same as the conventional one, and damage to the sealing member etc. can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a cutaway view of a differential device embodying the present invention, and FIG. 2 is a cutaway view similar to FIG. 1, showing the differential device installed in the middle of a propeller shaft or the like. Explanation of main drawing symbols, 1... Differential case, 3
... Sealed room, 25, 27 ... Rotating plate, W, W ₁ ...
...Output shaft (transmission shaft).

Claims (1)

[Claims] 1 A rotatable sealed chamber filled with viscous fluid is formed, and a rotary plate that continues to one transmission shaft side through the sealed chamber, and a rotating plate that faces the rotary plate and continues to the other transmission shaft side. A case is connected to the one or the other transmission shaft directly or indirectly through a differential device so as to cover part or all of the outer periphery of the sealed chamber with a slight gap. A power transmission device characterized in that the outer circumferential wall of the sealed chamber is brought into contact with the inner circumferential wall of the case to generate friction torque when the sealed chamber is elastically deformed due to an increase in internal pressure.