UA32745U - Controllable unbalance vibration exciter - Google Patents

Abstract

A controllable unbalance vibration exciter consists of housing, control mechanism located in it and unbalanced shaft with helical grooves, on which one fixed eccentric mass is fastened and two mobile eccentric masses connected to the shaft by ball cotters, the static moment of each mobile eccentric mass is equal to half of the static moment of fixed eccentric mass. The ball cotters, which connect the mobile eccentric mass to the shaft, are located in plane, which passes through the axis of the shaft and is perpendicular to the axis of symmetry of the eccentric mass.

Description

Description of the invention

The useful model belongs to the vibration technique, namely to the unbalanced vibration exciters of technological 2 vibration machines of various purposes.

There is a well-known vibration exciter in which one unbalance (stationary) is permanently fixed to the last on the unbalanced shaft, and the other can be moved along the shaft with the help of a control mechanism and at the same time turn relative to the stationary one by a certain angle |11.

The imbalance shaft is made hollow, through grooves are cut through it, through which the fingers 70 of the rod, which connects the movable imbalances with the shaft, pass.

The disadvantage of such a technical solution is a significant reduction in the strength and rigidity of the unbalanced shaft. This drawback is eliminated by the fact that the unbalance shaft is made continuous, it forms helical grooves along which the ball keys connecting the movable unbalances with the shaft |21 roll.

But the two ball keys connecting the movable imbalance to the shaft are located in a plane passing through 12 both sides of the symmetry of the movable imbalance.

The disadvantage of this technical solution is that the cross-section of the unbalanced shaft is weakened by two semicircular cutouts in the cross-section locations farthest from the neutral axis of the shaft.

In connection with the latter, to ensure rigidity and strength, it is necessary to increase the diameter of the shaft, which leads to an increase in the dimensions of the control mechanism and the entire vibration exciter.

The basis of the useful model is the task of increasing the bending strength of the unbalanced shaft, for which to improve the design of the controlled unbalanced vibration exciter due to the fact that the proposed controllable unbalanced vibration exciter consists of a housing, the control mechanism is placed in it, and an unbalanced shaft with screw grooves, on which is fixed one fixed imbalance and two movable imbalances connected to the shaft by ball pins, the static moment of each movable imbalance is equal to 22 half of the static moment of the fixed one, and the ball pins connecting the imbalances to the shaft are located in - a plane passing through the axis of the shaft perpendicular to the axis of symmetry of imbalances.

The location of the ball keys in a plane perpendicular to the axis of symmetry of the imbalances leads to the fact that the cross-section of the imbalance shaft has a weakening in the form of semicircular cutouts in the most vulnerable zone - on the neutral axis of the shaft, which works for bending under the action of the centrifugal forces of inertia of the imbalances. i am

Fig. 3 shows a movable unbalance connected to the unbalance shaft by ball keys placed Э on the axis of symmetry of the unbalance. Fig. 4 shows a movable imbalance, connected to the shaft by ball keys, which are placed in a plane passing through the axis of the shaft perpendicular to the axis of symmetry of the imbalance. Fig. 5 shows a cross-section of an unbalanced shaft with weakening in the form of a semicircle in the lower and upper zones farthest from the neutral axis during bending. Fig. b shows a cross-section of an unbalanced shaft with weakening in the form of a semicircle, located on the neutral axis. Fig. 7 shows the calculation diagram of an unbalanced shaft for bending due to the action of the outward forces of inertia of moving imbalances. Fig. 1 shows the general view of the vibration exciter. Fig. 2 shows the kinematic diagram of the vibration exciter, illustrating the generated centrifugal forces of inertia of imbalances. "

The controlled vibration exciter consists of a housing 1, which houses an unbalance shaft 2 with one 50 stationary unbalance Z and two movable unbalances 4, which are located on two sides of the stationary one and each t s of them has a static moment of mass two times smaller than that of the stationary one of imbalance 3. Movable imbalances 4 are connected to the imbalance shaft 2 due to screw grooves 5 and ball pins b. Through the bearings 7, the movable imbalances are connected to the forks 8, which, through the threaded bushings U, interact with the lead screw 10, on one part of which the right thread is placed, and on the other - the left thread. Together with the motor-reducer 11, the running screw 10, the threaded bushings 9 and the fork 8 make up the mechanism for controlling the moving imbalances 4. The controlled vibration exciter works as follows. with During the start of the drive motor, the movable imbalances 4 occupy a position diametrically opposite to the position of the stationary imbalance 3. Angle 86-02, After the drive motor comes to a stable mode, and control of the movable imbalances takes place. Motor-reducer 11 rotates the running screw 10 and moves t" 50 threaded bushings 9 together with forks 8 to the opposite sides of the fixed imbalance 3. Forks 8 interact through bearings 7, which are fixed on the hubs of the movable imbalances 4, and move the movable imbalances in opposite directions in the directions along the shaft 2. The ball keys 6 roll along the screw grooves 5 and force the movable imbalances 4 to turn at an angle of 96 relative to the stationary imbalance 3.

It is known that the main vector of inertia forces of such a vibration exciter is determined by the formula 59 Foaotvo? Sat. l where t is the mass of the movable unbalance, e is the eccentricity, y is the pitch of the helical groove on the s and 2 unbalanced shaft, o is the angular speed of rotation of the unbalanced shaft.

Each movable imbalance generates a centrifugal force of inertia E, which is equal to - 1 bottom? Sipb. .- These forces act 60 2 2 on the unbalanced shaft and cause it to bend (Fig. 7). The bending moment from the force E, located at a distance a from the shaft bearing, is determined by М-Е .а, and the amount of stress in the extreme fibers of the cross section of the shaft far from the neutral axis is equal to ,. M; This M/ is the moment of resistance of the section relative to the neutral axis. As can be seen from Fig. 5, the weakening of the shaft by helical grooves when the ball keys are placed in the plane 65 passing along the axis of symmetry of the imbalance leads to a significant decrease in the moment of resistance M/ and to a decrease in the bending strength of the shaft. Placing the keys as proposed in this solution (Fig. 4) leads to a weakening of the shaft on the neutral axis (Fig. b), which almost does not affect the magnitude of the moment of resistance and provides greater strength of the unbalanced shaft.

Used sources: 1. A.S. 1281312, USSR, cl. VOEV 1/16, B.I. Mo, - 1987. 2. A.S. 1484634, USSR, cl. В24В 31/06, B.I. Mo21, - 1989.

Claims (1)

The formula of the invention Controlled unbalanced vibration exciter consisting of a housing, a control mechanism placed in it and an unbalanced shaft with helical grooves, on which one fixed unbalanced and two movable unbalanced are fixed, connected to the shaft with ball pins, the static moment of each movable is equal to half of the static moment fixed imbalance, which differs in that the ball keys that connect the movable imbalances to the shaft are located in a plane passing through the axis of the shaft and perpendicular to the axis of symmetry of the imbalance. - iv) "I cha s Zo "o - with . and? o ko - FT" (l s 60 b5