SU1739116A1 - Safety friction clutch - Google Patents

Abstract

Use: limiting the amount of transmitted torque. The coupling halves are connected by a friction disk, pressed against the stop disc of one of the coupling halves. The pressure is applied by the main spring. The pressure disk is located between the friction and stop disks, concentric to the latter and pressed against the first additional spring. The balls are located in variable depth slots between the thrust and pressure discs. When overloaded, the pressure disk shifts in the circumferential direction and the balls come into contact with the sockets of variable depth, starting to transmit a torque. The spacing force that arises at the same time reduces the pressure of the main spring. 2 Il.

Description

The invention relates to mechanical engineering, in particular to devices for transmitting torques of limited magnitude.

Known safety friction clutch, containing two coupling halves connected by a friction disk, a primary and additional pressure discs which are concentric with each other, and a push-off assembly with a pressure sleeve connected to an external pressure disc (a. C. USSR No. 1455079, CL F 16 D 7/02, 1986).

The clutch has a low durability due to the wear of friction surfaces.

Closest to the proposed technical essence and the achieved result is a safety friction clutch, which contains the drive and driven coupling halves, coupled to the friction disk, which is spring-loaded to the resistant coupling fixed to the drive coupling half.

a disk, a pressure disk mounted on the drive half coupling, concentric to the thrust disk with the possibility of rotation and axial movement and spring-loaded to the friction disk with an additional spring, as well as rolling elements placed in variable depth slots between the outer and inner parts of the pressure disk (USSR No. 1339329, CL F 16 D 7/02, 1986).

The disadvantage of the coupling is the low durability due to the wear of the friction pairs,

The purpose of the invention is to increase the durability of the coupling by reducing the wear of the friction pairs.

The goal is achieved by the fact that in the safety friction clutch, which contains the driving and driven coupling halves, connected by a friction disk, spring-loaded to the stop disk fixed to the drive coupling half, a pressure disk mounted on the drive coupling half, concentric to the stop disk with the possibility

&

rotation and axial movement and spring-loaded for frictional interaction to the friction disk with an additional spring, as well as rolling bodies placed in two parts, variable depth seats, one part of which is made on the pressure disk, the pressure disk is located between the stop and friction disks, and an additional spring is between the stop. and pressure discs, the second part of the variable depth sockets is made in the stop disk, and the angle a is between the side surface of each variable depth socket and the axial plane ufty extending through the center of this jack The corresponding rolling body is selected under the following conditions:

variable depth, transmitting torque.

The nominal torque of the coupling is

T Rf (F-Fi),

0)

where R is the average friction radius between the resistant and friction 3 discs;

f is the coefficient of friction between the indicated disks, corresponding to the nominal torque;

F is the initial force of the spring 4;

FI is the same for spring 7.

Coupling torque when slipping

Ti Rf (F-Fi-Fp) + Rifi (Fi + Fp),

(2)

tga

R f

where r is the radius of the circle on which the rolling bodies are located;

R is the average radius of friction between the thrust and friction discs;

f- coefficient of friction between stubborn and fractional disks.

FIG. 1 is a schematic diagram of a safety friction clutch; in fig. 2 shows section A-A in FIG. one.

The safety friction clutch contains the driver 1 and the driven 2 coupling halves connected by the friction disk 3. The latter is pressed against the stop disk fixed rigidly on the coupling half 1 by the spring 4, the compression force of which is adjusted by means of the adjusting element 5.

The pressure disk 6 is mounted for rotation and axial movement relative to the coupling half 1 between the stop and friction 3 discs and is spring-loaded to the latter by an additional spring 7 installed between the stop and pressure b discs. The spring force 7 is less than the spring 4 force.

The balls 8 are placed in the sockets of variable depth, made on the thrust and pressure b disks.

The clutch works as follows

The spring 4 is adjusted to the force at which the clutch transmits the nominal torque to a pair of stop disk - friction disk 3.

When an overload occurs, the friction disk 3 slips relative to the stop disk, while the pressure disk 6 rotates relative to the coupling half 1 and the balls 8 are wedged in the overload slots

where Fp - spreading force on the balls 8;

RI is the average friction radius between the friction 3 and pressure 6 disks;

f 1 - the coefficient of friction between these disks,

Expansion force is

with t Rifi (Fi + Fp)

tga

(3)

where g is the radius of the circle on which the balls 8 are located;

a is the angle between the side surface of the variable depth socket and the axial plane of the coupling passing through the center of the ball corresponding to this socket.

Solving equation (3), we get:

Fn

FI Rifi tga d-Rifi tga

(four)

Substituting the result from (4)

and (2), we have:

Ti (F-Fi) Rf + Fi Rifix

r-R.gg (Rf-R f - (5

To satisfy condition T, it is necessary that the second term in (5) be a negative value, which is ensured by the following inequality:

 (R f - Ri f 1) Oh,

g - R-if i tg a

which, we get:

(6)

Fulfillment of this condition ensures a reduction in the moment of coupling slip as compared with the nominal moment, which allows reducing wear of the friction pairs and increasing the durability of the coupling.

Due to the specifics of the coupling can be performed only one disk.

The use of the invention will increase durability by reducing wear of friction pairs when triggered.

Claims (1)

Invention Formula A safety friction clutch containing the drive and driven half couplings connected by a friction disk, spring-loaded to the stop disk fixed to the drive half coupling, a pressure disk mounted on the drive coupling half, concentric resistance disk with the possibility of rotation and axial movement and spring-loaded friction interaction the friction disk with an additional spring, as well as rolling bodies, placed in two parts of the variable jacks depth, one part of which is made on the pressure disc, characterized in that, in order to increase durability by reducing wear of the friction pairs, the pressure disc is located between the stop and friction discs, and the additional spring between the stop and pressure discs, the second part of the sockets variable depth is made in a thrust disk, and the angle a between the side surface of each socket of variable depth and the axial plane of the coupling passing through the center of the rolling body corresponding to this nest is selected when observing uu following conditions: tga R-f where r is the radius of the circle on which the rolling bodies are located; R is the average radius of friction between the thrust and friction discs; f is the coefficient of friction between the resistant and friction discs. 3 f / Ak / / Aa increased yr