JPH0514667U - Bisca Skatling - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a viscous coupling having stable hump characteristics, capable of highly efficient torque transmission without degrading silicone oil, and having a simple structure. A friction plate 53, which is a non-metallic friction member, is provided between adjacent inner plates 57 and outer plates 55 so that the inner plates 57 and the outer plates 55 do not come into direct contact with each other.
Is provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a viscous coupling that transmits torque via a viscous fluid.

[0002]

[Prior Art]

 Generally, for example, it is used as a power transmission device in a power transmission system between front and rear axles of a four-wheel drive vehicle (4WD vehicle) or as a differential limiting device in a power transmission system between left and right wheels of a two-wheel drive vehicle. The viscous coupling includes first and second transmission members rotatably arranged relative to each other, two plate sets, and a working chamber in which a viscous fluid (silicon oil) is sealed. The plate set is slidable in the rotation axis direction of the first transmission member and is rotatably arranged together with the first transmission member, and the second plate set is arranged in the rotation axis direction of the second transmission member. Slidable and rotatably arranged with the second transmission member, each plate of the first and second plate sets is alternately arranged in the working chamber, and at least one plate Pairs of plates are spaced from each other It is maintained.

In such a viscous coupling, the transmission torque changes substantially in proportion to the rotational speed difference due to the relative rotation of the first and second plate sets, but the relative rotation exceeds a certain level for a long time. When the viscous coupling is activated, the internal temperature and internal pressure increase, causing a so-called "hump phenomenon" in which the transmission torque rapidly increases. This is because the internal temperature rises due to the stirring resistance of the silicone oil enclosed in the operating chamber, the silicone oil expands, and the enclosed air is compressed together with the silicone oil, so that bubbles of the air are generated in each plate. It becomes impossible to absorb the pressure difference generated on both sides of the plate, and it occurs when the plates of one plate set which can move in the axial direction move and start to come into direct contact with the plates of the other plate set. That is, the torque transmission due to the viscosity of the silicone oil between the plate sets is switched to the torque transmission due to the frictional contact of the plates between the plate sets, so that the transmission torque rapidly increases.

Further, for example, like a viscous coupling disclosed in Japanese Patent Laid-Open No. 62-37429, by inserting a disk made of a shape memory alloy or a bimetal between the plate groups as described above, It has also been proposed that the disk is deformed as the temperature inside the working chamber rises and frictionally contacts each plate group to transmit torque, thereby increasing the transfer torque.

Therefore, such a viscous coupling is used as a power transmission device in a power transmission system between front and rear axles of a 4WD vehicle or as a differential limiting device in a power transmission system between left and right wheels of a rear-wheel drive vehicle. In this case, by effectively utilizing the humped state due to the frictional contact between the plate groups as described above, the driving force can be transmitted to the other wheels with high efficiency even if one wheel idles. Therefore, it is possible to improve the running performance on a rough road of the vehicle.

[0006]

[Problems to be solved by the device]

 However, since the plates and discs are made of metal, the frictional contact between the plate sets is metal-to-metal contact, so it is difficult to adjust the friction coefficient and set the transmission torque in the hump state. Yes, the hump phenomenon could not be used effectively.

Further, the metal contact as described above promotes the generation of the activated metal powder, and the activated metal powder modifies the silicone oil in the operation chamber, which causes the viscosity change and deterioration of the silicone oil. There's a problem. In particular, the shape memory alloy or bimetal disc is deformed into a spherical shape or a truncated cone shape and comes into line contact with each of the plate groups, so that local wear is likely to occur and metal powder is likely to be generated. ..

[0008] Therefore, an object of the present invention is to solve the above-mentioned problems, has a stable hump characteristic, can transmit torque with high efficiency without deteriorating the silicone oil, and has a simple structure. It is to provide a ring.

[0009]

[Means for Solving the Problems]

 The above object of the present invention is to provide first and second transmission members that are arranged so as to be rotatable relative to each other, a working chamber in which a viscous fluid is sealed, and a first transmission member that is non-rotatably engaged with the first transmission member. Adjacent in a viscous coupling having a plate set and a second plate set alternating with the first plate set in the working chamber and non-rotatably engaged with a second transmission member. A non-metallic friction member is disposed between the first plate set and the second plate set so that the first and second plate sets do not come into direct contact with each other. It is achieved by viscous coupling characterized by.

Note that, for example, the friction member is a paper lineig rotatably inserted between the first and second plate sets, a non-metallic material such as a resin or asbestos material, or a semi-metalic or sintered alloy. It consists of a disk. Further, the non-metallic friction member can be attached to both surfaces of the first or second plate set, or can be attached to the same side face of the first and second plate sets.

[0011]

[Action]

 When the rotation speed difference occurs between the first transmission member and the second transmission member and the internal pressure in the working chamber rises due to the expansion of the viscous fluid, the plate of one of the plate groups that can move in the axial direction moves. Then, the plates of the other plate set are brought into contact with each other via the friction member, so that the torque transmission is performed by frictional contact without directly contacting the metal plates.

[0012]

【Example】

 Hereinafter, an embodiment of the present invention will be described in detail with reference to the attached FIGS. 1 to 3 and 6.

First, the configuration of the power system of the 4WD vehicle using the embodiment of the present invention will be described with reference to FIG. This power system includes an engine 1, a transmission 3, a front differential 5 (a front wheel differential device), front axles 7, 9, left and right front wheels 11, 13, a transfer 17 including a direction changing gear set 15, It comprises a viscous coupling 19, a propeller shaft 21, a rear differential 23 (a rear wheel differential device), rear axles 25 and 27, left and right rear wheels 29 and 31, and the like.

Next, the configuration of the viscous coupling 19 will be described with reference to FIGS. 1 to 3. The housing 33 (first transmission member) and the hub 35 (second transmission member) are arranged so as to be rotatable relative to each other. The housing 33 is connected to the output shaft 39 of the transfer 17 by an integral spline 37, and is rotationally driven by the driving force from the engine 1. The hub 35 is connected by a spline 41 to a connecting shaft 43 on the propeller shaft 21 side.

A working chamber 45 is formed between the housing 33 and the hub 35, and the working chamber 45 is filled with high-viscosity silicone oil (viscous fluid). Further, X-rings 47, 47 (seal having X-shaped cross section) and back-up rings 51, 51 are arranged between the housing 33 and the hub 35 to keep the working chamber 45 liquid-tight.

As shown in an enlarged view in FIG. 2, outer plates 55 and inner plates 57 are alternately arranged inside the working chamber 45. The outer plate 55 (first plate) is spline-connected to the inner circumference of the housing 33 so as to be axially movable. A spacer ring 61 is arranged between the outer plates 55, and the outer plates 55 are restricted from moving in the rotation axis direction while maintaining a predetermined space. The inner plate 57 (second plate) is spline-connected to the outer periphery of the hub 25 so as to be movable in the axial direction, and a friction plate, which is a friction member, is provided between each inner plate 57 and the outer plate 55 adjacent to each other. 53 is provided.

As shown in FIG. 3, the friction plate 53 is an annular plate member having substantially the same diameter as the inner plate 57, and is loosely fitted to the outer periphery of the hub 35. The friction plate 53 is made of, for example, a non-metallic material such as paper lining, and a round hole 54 for communicating silicone oil is appropriately formed on the surface thereof.

Therefore, when the inner plates 57, which are arranged in parallel inside the working chamber 45, move in the rotation axis direction and make sliding contact with the friction plates 53 in the hump state, the friction plates 53 are adjacent to each other. Since it is slidably contacted with 55, torque is transmitted between the inner plate 57 and the outer plate 55 via the friction plate 53.

Therefore, the transmission torque between the inner plate 57 and the outer plate 55 in the hump state can be set by appropriately changing the material of the friction plate 53 to a material having a different friction coefficient. Further, since the inner plate 57 and the outer plate 55 do not come into direct contact with each other, it is possible to prevent the metal plates from contacting each other.

Next, the operation of the viscous coupling 19 will be described. The rotation of the housing 33 due to the driving force from the engine 1 is transmitted from the outer plate 55 to the inner plate 57 by the shearing resistance of the silicone oil, and rotates the hub 35. At this time, if the rotation difference between the outer plate 55 and the inner plate 57 is large, the differential limiting force becomes strong and a large torque is transmitted. If this rotation difference is small, the differential is allowed and the transmission torque becomes small.

Further, when the outer plate 55 and the inner plate 57 continuously rotate relative to each other at a rotational speed difference of a predetermined value or more for a long time, the stirring resistance of the silicone oil enclosed in the working chamber 45 may be increased. The internal temperature rises, the silicone oil expands, and the internal pressure in the working chamber 45 rises. Then, the inner plate 57 is moved in the direction of the rotation axis and is pressed against the outer plate 55 via the friction plate 53. Therefore, since the plates are in sliding contact with each other via friction members, the torque transmission characteristics are stable, and the friction plate 53 is made of a material having a relatively large friction coefficient, so that the inner plate when a hump state occurs. The transmission torque due to the frictional contact between 57 and the outer plate 55 can be increased.

Further, when the rotary torque is directly transmitted between the inner plate 57 and the outer plate 55, torque is transmitted through the friction plate 53 made of a non-metallic material, and the inner plate, which is a metal plate, is transmitted. Since the sliding contact surfaces of the plate 57 and the outer plate 55 do not contact each other, frictional contact between metals does not occur. Therefore, the activated metal powder that deteriorates the silicone oil in the working chamber 45 does not generate from the friction contact surface, and it is possible to prevent the viscosity change and deterioration of the silicone oil, and thus the differential durability of the viscous coupling. Is improved.

Next, the function of the viscous coupling 19 will be described according to the power performance of the vehicle shown in FIG. The rotation of the engine 1 is transmitted to the front differential 5 via the transmission 3 and is separately output to the left and right front wheels 11 and 13, and is also transmitted to the rear differential 23 via the transfer 17, the viscous coupling 19, and the propeller shaft 21. The rear wheels 29 and 31 are separately output.

When the rotational speed difference due to the relative movement between the front and rear axles is small, such as when driving on a good road, the viscous coupling 19 absorbs the rotational speed difference and the rear wheels 29, 31 have almost no driving force. Is not transmitted. Therefore, the vehicle is in the front-wheel drive 2WD state, the fuel efficiency is improved, and the tit corner braking phenomenon does not occur even when the vehicle turns into a garage or makes a slow turn such as a U-turn.

When the front wheels 11 and 13 run idle on a rough road or the like and a rotation speed difference occurs between the front and rear axles, and the rotation speed difference between the rotation of the housing 33 and the rotation of the hub 35 is large, Due to the torque transmission characteristics of the viscous coupling 19, the driving force is split and output from the transfer 17, the viscous coupling 19, and the propeller shaft 21 to the left and right rear wheels 29 and 31 via the rear differential 23, and the vehicle enters the 4WD state. High running performance is obtained.

Further, when the front wheels 11 and 13 are stuck in mud or the like and the vehicle is stuck, the difference in the number of rotations between the front and rear axles increases and the relative rotation continuously occurs for a long time. The coupling 19 causes a hump condition. As a result, the torque transmitted by the viscous coupling 19 sharply increases and the transmission efficiency of the driving force to the rear wheels 29, 31 increases, so that a high driving force is generated in the rear wheels 29, 31 and the It becomes possible to escape.

In the above embodiment, the friction plates 53 are loosely fitted to the outer periphery of the hub 35 and are arranged between the inner plates 57 and the outer plates 55 adjacent to each other, but the present invention is not limited to this. However, it may take various forms as shown in FIGS. 4 and 5.

Outer plates 55 and inner plates 59 are alternately arranged inside the working chamber 45 of the viscous coupling 70 shown in FIG. 4 according to another embodiment of the present invention. The outer plate 55 (first plate) is spline-connected to the inner circumference of the housing 33 so as to be axially movable. A spacer ring 61 is arranged between the outer plates 55, and the outer plates 55 are restricted from moving in the rotation axis direction while maintaining a predetermined space. The inner plate 59 (second plate) is spline-connected to the outer periphery of the hub 35 so as to be movable in the axial direction.

Friction sheets 58, which are friction members, are integrally attached to both surfaces of the inner plate 59. The friction sheet 58 is formed of a non-metal material such as paper lining.

Therefore, when the inner plates 59 arranged in parallel inside the working chamber 45 are moved in the rotation axis direction in the hump state, they are brought into sliding contact with the adjacent outer plates 55 via the friction sheet 58. Torque is transmitted between the inner plate 59 and the outer plate 55 via the friction sheet 58.

Therefore, similarly to the viscous coupling 19 of the above-described embodiment, the friction sheet 58 is appropriately changed to a material having a different friction coefficient so that the friction between the inner plate 59 and the outer plate 55 in the hump state is increased. The transmission torque of can be set. Further, since the inner plate 59 and the outer plate 55 do not come into direct contact with each other, it is possible to prevent the metal plates from coming into contact with each other. Although the friction sheets 58 are attached to both sides of the inner plate 59 in this embodiment, the friction sheets 58 may be attached to both sides of the outer plate 55.

Further, according to another embodiment of the present invention, outer plates 64 and inner plates 65 are alternately arranged inside the working chamber 45 of the viscous coupling 71 shown in FIG. The outer plate 64 (first plate) is spline-connected to the inner circumference of the housing 33 so as to be axially movable. A spacer ring 61 is arranged between each outer plate 64, and each outer plate 64 is restricted from moving in the rotation axis direction while maintaining a predetermined space. The inner plate 65 (second plate) is spline-connected to the outer periphery of the hub 35 so as to be movable in the axial direction.

A friction sheet 66, which is a friction member, is integrally attached to the same side surface (left side surface in FIG. 5) of the outer plate 64 and the inner plate 65 over the entire surface. For example, it is formed of a non-metallic material such as paper lining.

Therefore, when the inner plates 65 arranged in parallel inside the working chamber 45 are moved in the rotation axis direction in the hump state, they are brought into sliding contact with the adjacent outer plates 64 via the friction sheet 66. Torque is transmitted between the inner plate 65 and the outer plate 64 via the friction sheet 66.

Therefore, like the viscous couplings 19 and 70 of the above-described embodiment, by appropriately changing the material of the friction sheet 66 to a material having a different friction coefficient, the inner plate 65 and the outer plate 64 in the hump state. The transmission torque between can be set. Further, since the inner plate 65 and the outer plate 64 do not come into direct contact with each other, it is possible to prevent the metal plates from contacting each other.

Further, in the viscous couplings 70, 71 of each of the above-mentioned embodiments, the friction sheet is attached over the entire surface of the inner plate surface or the outer plate surface, but it is not always necessary to attach the friction sheet, and the friction member is concentric. They may be arranged radially or radially.

Further, in each of the above-mentioned embodiments, an example in which the viscous coupling of the present invention is arranged on the propeller shaft of a 4WD vehicle has been described, but the present invention is not limited to this, and the differential of a rear-wheel drive vehicle is described. It can also be used for other power transmission devices such as a restriction device, and accordingly, the housing and the hub can have various shapes.

[0038]

[Effect of the device]

 According to the viscous coupling of the present invention, there is no direct contact between the first plate set and the second plate set which are adjacent to each other in the working chamber. Since the non-metallic friction member is arranged as described above, when the internal pressure in the working chamber rises and the first plate set is moved in the rotation axis direction, the first plate set is moved by the friction member. Is pressed against the second set of plates via. Therefore, when a hump condition occurs, each plate group slides in contact with each other via friction members, so the torque transmission characteristics are stable, and the friction members are made of a material with a relatively large friction coefficient. The transmission torque due to the frictional contact between the first plate set and the second plate set when the hump state occurs can be increased.

Further, in the hump state, torque is transmitted through the friction member made of a non-metallic material, and the sliding contact surfaces of the first plate set and the second plate set, which are metal plates, do not contact each other. , Does not cause frictional contact between metals. Therefore, the activated metal powder that deteriorates the silicone oil in the working chamber does not generate from the frictional contact surface, and it is possible to prevent the viscosity change and deterioration of the silicone oil, so that the differential durability of the viscous coupling is improved. improves.

Therefore, it is possible to provide a viscous coupling having a stable hump characteristic, capable of highly efficient torque transmission without deteriorating the silicone oil, and having a simple structure.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a viscous coupling according to an embodiment of the present invention.

FIG. 2 is a partially enlarged view of the viscous coupling shown in FIG.

FIG. 3 is a front view of the friction plate shown in FIG.

FIG. 4 is a partially enlarged view of a viscous coupling according to another embodiment of the present invention.

FIG. 5 is a partially enlarged view of a viscous coupling according to another embodiment of the present invention.

6 is a skeleton mechanism diagram showing a power system of a vehicle using the viscous coupling shown in FIG.

[Explanation of symbols]

 1 Engine 3 Transmission 5 Front Diff 7,9 Front Axle 11, 13 Front Wheel 15 Directional Gear Set 17 Transfer 19 Viscous Coupling 21 Propeller Shaft 23 Rear Diff 25,27 Rear Axle 29,31 Rear Wheel 33 Housing (First Transmission Member) ) 35 Hub (second transmission member) 37,41 Spline 39 Output shaft 45 Working chamber 47 X ring 51 Backup ring 53 Friction plate 54 Round hole 55,64 Outer plate (first plate) 57 Inner plate (second Plate) 58 Friction sheet 59 Inner plate (second plate) 61 Spacer ring 62,63 Spline engagement means 65 Inner plate (second plate) 66 Friction sheet 70 Viscous coupling 71 Viscous coupling

Claims (1)

[Scope of utility model registration request] 1. A first and a second rotatably arranged relative to each other.
Of the transmission member, the working chamber in which the viscous fluid is sealed, the first plate set engaged with the first transmission member in a non-rotational manner, and the first plate set and the working chamber are alternately arranged. And a second transmission member and a second plate set that is non-rotationally engaged with the viscous coupling, the first plate set and the second plate set that are adjacent to each other are A non-metallic friction member is disposed so that the first and second plate sets do not come into direct contact with each other, and a viscous coupling.