JPH0717858Y2 - Power transmission mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of use) The present invention is a power transmission mechanism that is disposed between a pair of rotating members that are coaxially and relatively rotatable and that transmits power between these two members. Regarding

(Prior Art) Such a power transmission mechanism is disposed between a driving side rotation member and a driven side rotation member, and when these both members relatively rotate, these two members are connected to each other so that power can be transmitted to the driven side rotation member. A member used as a connecting mechanism for driving members, a driving-side driven member, a driven-side rotating member, both driving-side rotating members, or both driven-side rotating members. Are connected to each other so as to be able to transmit power to each other, and are roughly classified into those used as a differential limiting mechanism for limiting the rotation difference between these two members. The former coupling mechanism is mainly arranged on one power transmission path in a real-time four-wheel drive vehicle, and the latter differential limiting mechanism is mainly arranged on each differential in the vehicle.

Thus, as a conventional power transmission mechanism, Japanese Patent Laid-Open No. 63-2404
As disclosed in Japanese Patent Publication No. 29, it is arranged between a pair of rotating members that are coaxially and relatively rotatable with each other, and actuated by relative rotation of these rotating members to connect them so that power can be transmitted. Generating frictional engagement force and increasing / decreasing the frictional engagement force according to the applied pressing force, and generating frictional force by generating pressing force according to relative rotation of both rotary members. Means for applying a pressing force to the means, the pressing force generating means being fluid-tightly slidable between the rotating members in the axial direction and integrally rotatable with one of the rotating members so that the friction A fluid chamber, in which a viscous fluid is enclosed, is formed between the working piston abutting on the engaging force generating means and the one rotating member so as to be integrally rotatable with a predetermined space in the axial direction between the working piston and the working piston. And a retainer There is one or more consisting constituted by a rotor integrally assembled to the rotating member of the other by said fluid chamber comprising a vane section power transmission mechanism radially extending.

In this type of power transmission mechanism, when a relative rotation occurs between both rotary members, a differential piston and a retainer that are integrally rotatable with one rotary member and a rotary piston are integrally assembled with the other rotary member. Relative rotation occurs with the rotor, the viscous fluid in the viscous fluid enclosure chamber defined by the vane part of the rotor of the fluid chamber is forced to flow, and pressure is generated in the enclosure chamber due to flow resistance. To do. That is, a pressure corresponding to the differential rotation speed is generated in the pressing force generating means. This pressure pushes the differential piston in the axial direction to press the frictional engagement force generating means, and the frictional engagement force for connecting the two rotating members to the power transmission means is generated. The frictional engagement force is proportional to the differential rotation speed, and the power proportional to the differential rotation speed is transmitted between the two rotary members from one to the other. Therefore, the power transmission mechanism functions as a coupling mechanism between the drive-side rotating member and the driven-side rotating member in one power-transmitting system path of the four-wheel drive vehicle and rotates between the drive-side and driven-side rotating members and both drive-side rotating members. It also functions as a differential limiting mechanism between members or between both driven side rotating members.

(Problems to be solved by the invention) By the way, in the power transmission mechanism of the above-mentioned type, even when the relative rotation between both rotary members is either forward or reverse,
That is, the torque transmission characteristics are the same regardless of whether the rotational speed of one rotating member is faster or slower than the other rotating member. For this reason, when the vehicle has a tight corner braking phenomenon during four-wheel drive, torque transmission may not be reduced and the tight corner braking phenomenon may not be sufficiently prevented.
Further, it may not always be sufficient to set the traveling performance of the vehicle to an arbitrary performance.

Therefore, an object of the present invention is to solve the above-mentioned problems by configuring the power transmission mechanism of this type so that the torque transmission characteristic is changed when the relative rotation between both rotary members is forward and reverse.

(Means for Solving the Problems) In the power transmission mechanism of the above-described type, the present invention forms the vane portions on both sides in the circumferential direction so as to have mutually different shapes, and if the drag forces on the viscous fluid on both sides are different from each other. It is characterized by having been done.

(Operation and Effect of the Invention) According to such a configuration, since the drag force on the viscous fluid on each side surface of the vane portion of the rotor is different from each other, the two side surfaces in the axial direction of the rotor and one side surface of the differential piston and the retainer are different from each other. When the flow rate of the viscous fluid flowing from one enclosure to the other enclosure through the minute gap differs between forward and reverse rotation, and when the relative rotation of the rotor is in the direction in which the flow rate of the viscous fluid is small, the pressure generated in the enclosure is When the flow rate is large and the flow rate of the viscous fluid is large, the generated pressure is small. Therefore, the pressing force generated by the pressure generating means is different when the relative rotation between both rotary members is forward and reverse, and therefore the torque transmission characteristics are also different.

(Embodiment) The first embodiment of the present invention will be described below with reference to the drawings.
An embodiment of the power transmission mechanism according to the present invention is shown in the drawings. As shown in FIG. 4, the power transmission mechanism 10 is arranged in the rear-wheel-side power transmission system of a real-time four-wheel drive vehicle.

In the vehicle, the front wheels are always driven and the rear wheels are driven when necessary.The transaxle 22 mounted on one side of the engine 21 has a transmission and a transfer, and outputs power from the engine 21 to the axle shaft 23. Drive the front wheels 24 and output to the first propeller shaft 25. The first propeller shaft 25 is connected to the second propeller shaft 26 via the power transmission mechanism 10. If both shafts 25, 26 can transmit power, the power is transmitted via the rear differential 27 to the axle shaft.
It is output to 28, and the rear wheel 29 is driven.

Thus, the power transmission mechanism 10 has a pressing force generating means in the annular working chamber composed of the outer case 11 and the inner shaft 12.
10a and a frictional engagement force generating means 10b.

The outer case 11 is provided with an inward flange portion 11b at one end of a tubular portion 11a having a predetermined length, the other end of the tubular portion 11a is open, and a threaded portion 11c is formed on the inner circumference of the other end. The inner shaft 12 is provided with an outward flange portion 12b on the outer periphery of the intermediate portion of a stepped tubular portion 12a of a predetermined length, and an outer spline portion 12c extending in the axial direction is formed on the outer periphery of the flange portion 12b. An inner spline portion 12d extending in the axial direction is formed on the inner periphery of one end side of 12a. In the inner shaft 12, one end of the tubular portion 12a is fitted in the inner hole of the inward flange portion 11b of the outer case 11 in a liquid-tight and rotatable manner, and is assembled to the outer periphery of the other end of the tubular portion 12a. It is rotatably supported by the outer case 11 via the constituent members of the attached pressing force generating means 10a described later. The inner shaft 12 is fitted and fixed to the spline 26a at the tip of the second propeller shaft 26 by the inner spline 12d, and the outer case 11 is fixed to the rear end of the first propeller shaft 25.

The pressing force generating means 10a is composed of an operating piston 13, a rotor 14 and a retainer 15, and the friction engagement force generating means 10b is of a wet multi-plate clutch type and has a large number of clutch plates 16.
And a clutch disc 17. Each clutch plate 16 has a raised portion on the outer periphery thereof fitted into a groove portion 11d provided on the inner periphery of the outer case 11, and is assembled to the case 11 so as to be integrally rotatable and movable in the axial direction. Each clutch disc 17 has its inner peripheral raised portion fitted to the outer spline portion 12c of the inner shaft 12 so as to be positioned between the clutch plates 16 and assembled to the shaft 12 so as to be integrally rotatable and movable in the axial direction. It is attached. These clutch plates 16
A predetermined amount of clutch oil and gas is sealed in the storage chamber R1 of the clutch disc 17.

The working piston 13 that constitutes the pressing force generating means 10a is integrally rotatable with the inner circumference of the other end side of the tubular portion 11a of the outer case 11 and is slidable in the liquid-tight axial direction. The outer periphery of the clutch plate 16 is rotatably and slidably mounted in the axial direction. As shown in FIG. 1 and FIG.
Two vanes 14 that extend in the radial direction at 80 ° apart
It is provided with b, and is fitted integrally with the inner shaft 12 by being fitted to the outer periphery of the cylindrical portion 12a of the inner shaft 12 by the annular boss portion 14a. In the rotor 14, the annular boss portion 14a has an annular recess 1 provided on the other side of the differential piston 13.
The vane portion 14b is formed in a streamline shape having a thickness substantially equal to the depth of 3b and protruding toward one end side as shown in FIG. 3 (a), and is fitted in the annular recess 13b. . Vane section 1
The other end of the 4b is formed into the end face 14b ₁ orthogonal to the circumferential direction, drag is mutually different for the viscous fluid to the streamlined shape surface 14b ₂ of the end surface 14b ₁ and one end. The retainer 15 has a threaded portion 15a on the outer periphery on the other end side, and the cylindrical portion 12a of the inner shaft 12
Is fitted to the outer periphery of the other end side in a liquid-tight manner so as to be slidable and rotatable in the axial direction.
Is screwed to the screw part 11c of the outer case 11 so as to be able to move forward and backward,
And it is liquid-tight. The retainer 15 is axially adjusted in position and fixed to the outer case 11 by caulking means.
The third outer surface 13c is in contact with the other annular outer edge surface 13c, and one side surface 15b thereof and the annular recess 13b of the differential piston 13 form a fluid chamber in which the rotor 14 is located. A predetermined amount of highly viscous fluid such as silicone oil is enclosed in this fluid chamber.
Reference numeral 14 designates the outer periphery of the vane portion 14b in liquid-tight contact with the inner periphery of the annular recess 13b, and both sides of the end face 14b1 side of the vane portion 14b and the multi-end surface 13b1 of the annular recess 13b and _one side surface of the retainer 14. 15b
A minute gap is formed between them to divide the fluid chamber into two retention chambers R2 for enclosing the high-viscosity fluid.

In the power transmission mechanism 10 having such a configuration, when relative rotation does not occur between the first and second propeller shafts 25, 26, torque is not transmitted between the two shafts 25, 26, but both shafts 25, 26 When relative rotation occurs between 26, torque is transmitted. That is, when a relative rotation occurs between the shafts 25 and 26, the outer case 11, the working piston 13 and the retainer 15 that are integrally rotatably assembled to the first propeller shaft 25 and the second propeller shaft 26 are integrated. Relative rotation occurs between the rotatably mounted inner shaft 12 and rotor 14. Therefore, in the fluid chamber of the pressing force generating means 10a, the viscous fluid in the retention chamber R2 is forcibly flown at a speed proportional to the relative rotation speed, and flows in the retention chamber R2 that sequentially shifts in the circumferential direction. Due to the resistance, from the downstream end of the vane portion 14b to the next vane portion 14b.
A pressure distribution in which the pressure is gradually increased toward the upstream side end of the pressure distribution is generated. The pressure increase portion of this pressure distribution increases in proportion to the differential rotation speed. The clutch plates 16 and the clutch disc 17 that form the engaging force generating means 10b are frictionally engaged with each other via the clutch oil. As a result, in the frictional engagement force generating means 10b, the torque proportional to the differential rotation speed is transmitted from the outer case 11 to the inner shaft 12, and the vehicle is in the four-wheel drive state. Further, in this four-wheel drive state, differential rotation of the front and rear wheels is allowed, and the occurrence of the tight corner braking phenomenon is prevented.

Meanwhile, in the power transmission mechanism 10, the circumferential direction of the other side surfaces and one side surface on the end surface 14b ₁ of the vane portion 14b of the rotor 14 have been formed in streamlined shape surface 14b _2, each other different resistance to viscous fluid Therefore, both axial side surfaces of the rotor 14 and the other side surface 13b ₁ of the working piston 13 and the retainer 15
The flow rate of the viscous fluid flowing from one side of the retention chamber R _{2 to} the other side through the minute gap between the one side surfaces 15b differs depending on the rotation direction of the rotor 14. The outer case 11 of the rotor 14 is the inner shaft
When the rotation speed is faster than that of 12, arrow A in Fig. 3 (a)
Relative rotation in the direction of arrow B, and when the rotation speed is low, relative rotation in the direction of arrow B. However, when rotating in the direction of arrow A, the flow rate of the viscous fluid is small and the generated pressure in the retention chamber R ₂ is large,
At the time of rotation in the direction of arrow B, the flow rate of the viscous fluid is large and the pressure generated in the retention chamber R ₂ is small. Therefore, the outer case
The torque transmission from 11 to the inner shaft 12 is large, and the torque transmission from the inner shaft 12 to the outer case 11 is small.

A modified example of the vane portion of the rotor 14 is shown in FIG. 3 (b), and the vane portion 14c has a trapezoidal cross section. This allows the end face 14
The c ₁ and the tapered surface 14 c ₂ have different drag forces against the viscous fluid. The cross section of the vane portion may have an appropriate shape that makes the drag forces different from each other.

[Brief description of drawings]

1 is a sectional view of a power transmission mechanism according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, and FIG.
FIG. 4A is an enlarged transverse sectional view of a vane portion of a rotor, FIG. 4B is an enlarged transverse sectional view showing a modified example of the vane portion, and FIG. 4 is a schematic view of a vehicle employing the same mechanism. Explanation of symbols 10 …… Power transmission mechanism, 10a …… Pressing force generating means, 10b ……
Friction engaging force generating means, 11 ... Outer case, 12 ... Inner shaft, 13 ... Working piston, 14 ... Rotor, 14
b, 14c …… Vane part, 15 …… Retainer, 16 …… Clutch plate, 17 …… Clutch disc, 25,26 …… Propeller shaft.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoyuki Sakai 1-1-1, Asahi-cho, Kariya city, Aichi Toyota Koki Co., Ltd. (56) Reference JP-A-2-209628 (JP, A) JP-A-64 -87928 (JP, A) JP-A-63-240429 (JP, A)

Claims (1)

[Scope of utility model registration request] 1. A frictional engagement force, which is disposed between a pair of rotating members coaxially and relatively rotatably positioned, is actuated by relative rotation of these rotating members to couple the rotating members so that power can be transmitted. And a frictional force generating means for increasing / decreasing the frictional force according to the applied pressure force, and a pressure force for generating the pressure force according to the relative rotation of the two rotary members and imparting the force to the frictional force generation means. The frictional force generating means includes a generating means, and the pressing force generating means is assembled so as to be liquid-tightly slidable in the axial direction between the rotating members and integrally rotatable with one rotating member. A retainer that forms a fluid chamber in which a viscous fluid is sealed at a predetermined interval in the axial direction between the working piston in contact with the one rotating member and the working piston so as to be rotatable integrally,
A power transmission mechanism comprising one or a plurality of vane portions extending in the radial direction and a rotor integrally assembled with the other rotating member in the fluid chamber, wherein both sides of the vane portion in the circumferential direction are provided. Form the surfaces in mutually different shapes,
A power transmission mechanism characterized in that the drag forces on the viscous fluid on both sides differ from each other.