SU473868A2 - Centrifugal start coupling - Google Patents

Description

one

The invention relates to the field of mechanical engineering and can be used, for example, in drives of textile machines for eliminating the starting breakage of threads or in drives of conveyors of coal combines to increase the service life of rubber bands.

According to the main author. St. No. 418645 is a known centrifugal starting coupling comprising a driving and driven coupling coupling with friction disks fixed to the monks and associated pressure and stop disks, as well as a centrifugal activation mechanism, made in the form of balls placed in a separator, freely installed between the pressure and resistance discs, and the working surfaces of the discs are made in the form of ellipsoids.

The clutch ensures smooth connection in accordance with the optimal growth law of the transmitted moment, however, since the balls can move to the periphery of the discs unhindered, it cannot provide load-free acceleration of the drive motor at the same time limiting the magnitude of the zero overloads of the parts of the working mask.

In the proposed coupling, in order to improve its starting characteristics, the separator is provided with an inertial mass, mainly a rim, and the windows in which the balls are placed are spiral-shaped.

FIG. 1 shows the proposed coupling, a cross section; FIG. 2 — rairez io aa a pas figs. one.

The centrifugal start-up clutch contains the leading 1 and the driven 2 half-couplings, connected by friction disks 3, and the centrifugal switching mechanism consisting of yno | iny Dpska 4 connected to the driving floor of the ftofi, supported through the spring 5 pa of the clamping disk 6 of the friction unit, 7 pieces separator 8. as well as a pressure disk 9. In order to reduce wear, the spring 10 and the thrust bearing 11 may be included in the congruction. When assembling the spiral-shaped separator window, it must be oriented in the direction of rotation, as indicated in FIG. 2. Spring 5

has greater lh stiffness and less shrinkage compared to 10, therefore, at rest, the balls 7 are clamped between the disks 4 and 9, and there is a gap between the pressing 6 and the friction 3 disks.

At the time of start-up of the electric motor, the leading coupling half 1, together with disks 4 and 6, is set in motion with acceleration, the half coupling 2 with disks 3 and 9 is fixed because of the presence of a gap.

The balls 7 rotate at half speed (acceleration), as they form a differential mechanism together with the disks 4 and 5, and they set in motion a separator 8 with this speed (acceleration). Due to the presence of acceleration, a moment of inertia forces acts on the separator, proportional and directed opposite to acceleration. Due to the spiral-shaped window shape, the moment of inertia force acting on the separator prevents the balls from moving from the center, i.e., turning on the coupling, until the acceleration is reduced to a predetermined value. This provides a load-free acceleration of the electric motor to a speed close to the nominal one.

After the moment developed by the clutch exceeds the moment of friction of the machine, the driven shaft will rotate rapidly:. During this period, the speed and acceleration of the separator will be determined by the half-sum of the velocities or accelerations of the driving and driven half coupling. When the acceleration value is exceeded, the separator moves the balls to the center and turns off the clutch.

With an increase in the angular velocity, the value of the centrifugal force acting on the balls increases, which leads to an increase in the values of the accelerations acting on the driven part of the clutch. To prevent this, as well as to eliminate the effect of wear in the friction assembly on the coupling parameters and preserve the safety properties of the coupling in the steady-state pressure mode, one of the disks, for example, 5, is spring-loaded and has

support surface as part of an ellipsoid.

Due to this, when the centrifugal force increases, the ball 7, compressing the spring 5, moves 5 the disk 9 to a position in which the wedging angle of the ball 7 between the disks 4 and 9 is larger, therefore, the force needed to move it down is less. This makes it possible to reduce the acceleration of the driven part to a given constant value.

The parameters of the window in the separator, the spring stiffness 5 and the angles of inclination of the supporting ellipsoidal surface of the disks 4 and 9 can be determined by calculation after calculating

5 friction clutch assembly. Leading can be either half-coupling 1 or zero-coupling 2.

Thus, the proposed clutch allows to obtain acceleration of an electric motor without load up to a speed close to the nominal, and acceleration of the driven part of the machine with accelerations close to constant for all the pre-set acceleration time, regardless of the type of load and operating conditions.

Subject invention

Centrifugal starting clutch by bus. St.

0 Ne 418645, characterized in that, in order to improve its starting characteristics, the separator is provided with an inertial mass, mainly the rim, and the windows in which the balls are placed are given a spiral shape.

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