JPH01224528A - Viscous coupling - Google Patents

Abstract

PURPOSE:To obtain a desired torque characteristic by providing a clutch fitting on an inner shaft so as to be capable of rotating and having an inner plate formed on the outer circumferential face thereof, and a centrifugal clutch composed of a clutch plate pressing said clutch case in contact therewith. CONSTITUTION:A silicon oil 8 is sealed in the inner part of a sealed outer case 2, and outer plates 4 are spline-bonded to the inside thereof. Inner plates 5 are spline-bonded to the outer circumferential face of an inner shaft 3, and one end of a pair of clutch plates 11 forming a centrifugal clutch 6 is installed in a flange part 3a through a support shaft 12, the other end being connected to one end of the other clutch plate 11 through a spring. Further, a clutch case 13 is fitted on the inner shaft 3 so as to surround the clutch plates 11, and inner plates 5a are fixed to the outer circumferential face of the clutch case. Thus, the number of plates acting as the inner plate 5a at a determined engine speed or more is increased to obtain a desired torque characteristic.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a viscous coupling using viscous fluid that is applied to a torque transmission unit of a four-wheel drive vehicle or the like.

(Prior Art) In a conventionally known viscous coupling, a hub shaft is rotatably inserted through a substantially cylindrical outer housing via a bearing, and the outer shell housing is provided between the hub shaft and the hub shaft. The inside is sealed by a seal member, and a highly viscous fluid such as silicone oil is sealed inside. A plurality of actuator plates are attached to the inner circumferential surface of this outer shell housing so as to be slidable in the axial direction and fixed in the rotational direction by serration coupling, etc., and a plurality of inner actuator plates are attached to the outer circumferential surface of the outer shell housing to the hub axle. The plates are fixed in the rotational direction by serration coupling or the like, and these outer plates and inner plates are arranged alternately in the axial direction. The distance between the acta plates is kept constant by a spacer ring that restricts movement in the axial direction.

It is known that a viscous coupling configured in this manner transmits torque by utilizing the shear stress generated when the viscous fluid is sheared by the actuator plate and the inch plate in response to the relative rotational speed difference between the actuator plate and the inch plate. .

(Problem B to be solved by the invention) The transmission torque of a viscous coupling is determined by the viscosity of the viscous fluid, the number of plates, the radius of the plates, the rotational speed difference between the outer plate and the inner plate, the gap between the plates, and the viscous fluid. It is determined by factors such as temperature and filling rate of viscous fluid.

Since the torque is a linear function of the difference in rotational speed, it is known that if factors other than the rotational speed are held constant, the transmitted torque will be approximately proportional to the rotational speed.

Furthermore, even if you change other factors that affect torque characteristics, such as viscosity, in order to obtain desired torque characteristics, the absolute value of torque will change if the value of the factor cannot be varied during operation of the viscous coupling. There is a problem in that it is difficult to generate a desired torque at a predetermined rotation speed without changing the shape of the curve representing the relationship between rotation speed and torque.

The present invention has been made in view of these problems of the conventional technology, and its purpose is to provide a viscous coupling with a degree of freedom in torque characteristics. .

(Means for Solving the Problems) In order to solve the above problems, the viscous coupling of the present invention includes a clutch case that is rotatably fitted to an inner shaft and has an inner plate formed on its outer circumferential surface; It is equipped with a centrifugal clutch consisting of a clutch plate that abuts and suppresses the

(Function) When the inner shaft reaches a predetermined number of revolutions or more, the centrifugal force causes the clutch plate to come into contact with and press the clutch case, and the inner plate formed on the clutch case is connected to the inner shaft and functions as an original inner plate.

(Example) Embodiments of the present invention will be described below based on the accompanying drawings.

Fig. 1 is a sectional view of the viscous coupling of the present invention, Fig. 2 is a sectional view of the viscous coupling of the present invention;
The figure is a view taken along the line A-A in FIG. 1.

The viscous coupling 1 includes an actor plate 4, an inner plate 5.5a, a centrifugal clutch 6, and a spacer in a sealed chamber formed by an actor case 2, which is a substantially cylindrical outer shell housing, and an inner shaft 3, which is a hub shaft. 7, silicone oil 8 as a viscous fluid, and an oil seal 9 as a fluid seal.

The inner shaft 3 has a bearing 10 in the outer case 2.
The inner shaft 3 is rotatably inserted through the inner shaft 3.
The inside of the outer case 2 is sealed by an oil seal 9 provided between the outer case 2 and the inside of the outer case 2, and silicone oil 8 is sealed inside.

Furthermore, a plurality of actor plates 4 are attached to the inner peripheral surface of the actor case 2 so as to be slidable in the axial direction and fixed in the rotational direction by spline connection.

A plurality of inner plates 5 are fixed to a part of the outer circumferential surface of the inner shaft 3 in the rotational direction by spline connection inside the outer case 2, and a pair of arc-shaped clutch plates 11, 11 forming the centrifugal clutch 6 are further attached to the inner shaft 3. are rotatably attached to the flange portion 3a of the other part of the inner shaft 3 via a support shaft 12°12, and the other end is attached to one end of the other clutch plate it, 11 with a spring 12a, 12a, respectively. connected via. A substantially cylindrical clutch case 13 is connected to the inner shaft 3 via a bearing 14 so as to surround the clutch plate 11.11.
A plurality of inner plates 5a are rotatably fitted into the grooves formed on the outer circumferential surface of the inner plates 5a.

These actor plates 4 and inner plates 5.5a are arranged alternately in the axial direction. The distance between the outer plates 4 is kept constant by a spacer 7 that restricts movement in the axial direction.

The operation of the viscous coupling configured as above will be explained below.

When transmitting torque from the inner shaft 3 to the outer case 2, the inner plate 5 is fixed to the inner shaft 3 and the actuator plate 4 is fixed to the outer case 2 in the rotational direction, and this occurs when the silicone oil 8 is sheared. It is similar to the conventional technology that torque is transmitted by the shear stress.

The viscous coupling 1 of the present invention has an inner plate 5
, 5a, n inner plates 5a are fixed to the clutch case 13, but the centrifugal clutch 6
When the clutch plates 11 and 11 are not pressed against the clutch case 13, the clutch case 13 is rotatably fitted to the inner shaft 3 and does not contribute to torque transmission.

However, as the rotational speed of the inner shaft 3 increases, the angular velocity and the preselected clutch plate 11.1
1 and the centrifugal force determined by the distance from the axis of the inner shaft 3 to the center of gravity of the clutch plate 11.11, and the spring 12a.

The clutch plate 11.11 comes into contact with and presses the clutch case 13 due to the pressing force determined by the elastic force of the clutch 12a, etc., and the clutch case 13 and the inner shaft 3 rotate as one. Then, the inner play (5a) contributes to torque transmission, and the viscous coupling 1 exhibits torque characteristics as shown in FIG.

This is because the transmitted torque is proportional to the number of plates, so before the centrifugal clutch 6 is connected, only the inner plate 5 contributes to torque transmission, resulting in a torque characteristic of (N-n) plates, but when the rotation speed is higher than Rrpm This is because when the centrifugal clutch 6 is connected, the torque characteristics will be that of all the inch plates 5.5a.

Therefore, the centrifugal clutch 6 is connected at a predetermined rotation speed, and the mass of the latch plate 11 and the inner shaft 3
Desired torque characteristics can be obtained by selecting the distance from the axis of the clutch plate 11.11 to the center of gravity of the clutch plate 11.11 and the elastic modulus of the spring 12a.

(Effects of the Invention) As explained above, according to the present invention, when the inner shaft reaches a predetermined number of revolutions or more, the centrifugal clutch is connected and the number of plates working as inner plates is increased, which is almost proportional to the number of revolutions. Since the related torque characteristics can be changed freely, albeit in stages, it becomes possible to obtain the desired torque characteristics.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the viscous coupling of the present invention, Fig. 2 is a sectional view of the viscous coupling of the present invention;
The figure is a view taken along the line A--A in FIG. 1, and FIG. 3 is a diagram showing the torque characteristics of the present invention. In the drawings, 1 is a viscous coupling, 2 is an outer case, 3 is an inner shaft, 4 is an outer plate, 5,
5a is an inner plate, 6 is a centrifugal clutch, 7 is a spacer, 8 is silicone oil, and 9 is an oil seal.

Claims (1)

[Claims] In a viscous coupling, which is a torque transmission unit that uses viscous fluid, a centrifugal clutch consists of a clutch case that rotatably fits onto an inner shaft and has an inner plate formed on its outer peripheral surface, and a clutch plate that presses against the clutch case. A viscous coupling characterized by the provision of.