SU63676A1 - Device for testing worm gears - Google Patents

Description

Devices for testing worm gears are known, the worm wheels of which are mounted on rigidly interconnected shafts, and the axis of the worm gears are interconnected by a cylindrical gear that receives rotation from the drive motor, and one of the worm shafts is under constant axial load . The present invention proposes in these known devices a worm shaft, to which a load is applied, to be split.

This embodiment of the shaft is intended to ensure the relative axial movement of the shaft parts without disturbing their rotation.

In FIG. 1 depicts the scheme of the proposed device, and FIG. 2 and 3 are a coupling for carrying out a load in a longitudinal section and in a top view.

Two identical gearboxes I and II are tested simultaneously. The shafts of the wheels 8 and 9 are rigidly connected to each other (Fig. 1). The shafts 1 and 2 of the screws 6 and 7 are connected by transmission with the cylindrical wheels 3, 4, 5. The wheel 4 is connected by a flange 13 to the shaft of the engine and drives the entire system.

Box 11 with ballpoint screw 7 of gearbox I is removed from the housing.

By applying a force Q (Qi) to the lever 10, the worm is loaded to 7 in the axial direction through the intermediary of the AND-fifth box. The teeth of the wheel 9 perceive the axial force imparted by the screw and prevent its movement. Thus, the circumferential force of the wheel 9 is equal to the force applied to the tip of the box 11.

In order to avoid unloading from friction forces, roller bearings are used as radial bearings of the screw 7, which do not prevent axial movement. Shaft screw 7, to which the load is applied, is made split and consists of parts 2 and 15 connected by a coupling 12, allowing axial movement of part 2.

The forces applied to the teeth of the wheel 9 from the side of the teeth of the screw 7 interlocking with it are shown by vectors shifted to the center. Chervy ki right.

When acting on the lever 10, the forces QI of the forces applied to the teeth of the wheels are shown in solid lines. The circumferential force applied to the teeth of the wheel 9 from the side of the worm 7 is directed against its peripheral speed and, therefore, the wheel 9 is the leading one and the worm to the 7 is the driven one. From the balance of the shaft 14 with the wheels 8 and 9 it follows that the forces PS and Re are oppositely designed. The direction of the force PS coincides with the direction of the peripheral speed and, therefore, the wheel 8 is the follower and the worm to the 6 is the leading one.

Wheel 3 is obviously a slave, so the direction of the force Ps coincides with the direction of the peripheral speed.

Thus, the force flow is directed from the wheel 4 to the wheel 3, from the screw 6 to the wheel 8, from the wheel 9 to the screw 7 and further from the wheel 5 to the wheel 4. The direction of the power flow under the action of force Qi and this direction of rotation is shown in solid arrows.

If you change the direction of rotation, retaining the same direction of force QI, then obviously the direction of force on the teeth does not change, and therefore the driving wheels (worms) are driven, and the driven ones are driven, i.e. the direction of the power flow is reversed and reducer I will work normally, transferring the power from the worm to the wheel, and reducer II will transmit the force from the wheel to the worm.

When acting on the lever 10, the force Q and the indicated direction of rotation, the direction of the forces and the force flows are shown by a dotted line. In this case, the reducer I is the worm to the leader, and the reducer II is the worm to the slave.

When the direction of rotation changes, the lead is the screw to the gearbox P and the follower to the gearbox. one.

Thus, when changing the directions of rotation and the load on the lever 10, each of the gearboxes can be made to work both with the master and with the driven screw, and in each of these two cases both working surfaces of the teeth are involved (alternately).

The conditions of the gearbox engagement with the lead worm are few

differ from the conditions of work with the slave screw. The main value characterizing these conditions is the force of pressing the threads of the screw to the teeth of the wheel; This force is affected by the loss of the mesh.

In the manner described, one can also test self-braking worm gears. Let the gearboxes I and P be self-braking, the worm to 6 is the master, and, the worm to 7 is the slave.

In this case, the force flow from the screw 7 will not return to the wheel 5, as was the case with non-self-locking gearboxes, and the wheel 5 will receive power from the wheel 4 and transmit it to the screw 7.

When the lever system is loaded with force Q (and, therefore, loaded worm gearboxes), after the moment from the motor is applied to the wheel 4, gaps may appear in the chain 4-5-15-12-2 (due to the lateral clearance between the teeth, dead strokes in the coupling 12, in keyed connections, etc.).

In this case, the worm to 7 is not affected by the moment from the shaft side and, consequently, due to self-braking, the rotation of the system is impossible with the use of conventional gearboxes. However, in this case, the worm to 7 has the ability to move in the axial direction and, therefore, gaps in the system 4-5- -15-12--2 will be selected during the turn of the wheel 4, during which the worm to 7 will move in the axial direction.

In this case, the work of the worm pair is similar to the work of a rack and pinion.

With a lead screw 7, gaps in chain 4-3-6 are selected by rotating the wheel 4 due to the axial movement of the screw 7 while the wheel 9 is stationary.

The movement of the screw 7 in this case is analogous to the movement of the screw with the fixed nut.

You can reproduce the variables in magnitude and direction of the load when testing gears in the following way.

Between two coaxial wheels (for example, in the case of testing in a closed way two identical gears with cylindrical wheels) or between a wheel and a worm. In the case of testing worm gears (for example, between a wheel and a worm in the diagram in Fig. 1), a special coupling for load (Fig. 2 and 3).

On shafts 1 and 2, which are rigidly connected to the test wheels (or the wheel and the worm in the case of the circuit in Fig. 1), the leashes 16 are fixed. Leads are pressed in axles 17 with ball bearings. The latter are inserted into the grooves of the box 18. By means of the lever system 19, the yoke 20 and the ball valves, the box 18 is loaded in the axial direction. Here, due to the inclined arrangement of the grooves in the box 18 for the bearings of the left leash, a certain moment will act on the links associated with the described coupling, varying in magnitude and direction with changing magnitude and direction of the force on the lever.

Subject invention

Claims (3)

1. A device for testing worm gearboxes, the worm wheels of which are mounted on rigidly interconnected shafts, and the axis of the worm gears are connected to each other through a cylindrical gear that receives rotation from a drive motor, in which the device one of the worm shafts is under constant axial load, characterized in that the worm shaft, to which the load is applied, is split in order to ensure the relative axial movement of the shaft parts without disturbing their rotation. 2. The device according to claim 1, characterized in that on the shafts rigidly connected to the wheel and the screw being tested, the drivers 16 are mounted, the pins of which are inserted into the inclined grooves of the box 18, which is influenced by the axially applied force. 3. The form of the device according to claim 2, wherein the pins of the leads 16 are provided with ball bearings. w 1np w umu FIG. 3