SU819451A1 - Variable-speed gear drive - Google Patents

Description

(54) TEETH VARIATOR

one

This invention relates to general engineering. The variator can be used at all points of the national economy to regulate the speed of the working body of the machine.

Gear variators are known comprising a driven shaft, a mounted on it a block of bevel gears, a drive shaft parallel to the block forming the shaft, a cylindrical gear wheel mounted on it with axial movement with a hub and a control mechanism acting on this wheel pj.

Switching speeds in such variators occurs under load, therefore, with frequent switching, there is a rapid wear of gears and splines of the drive shaft and spur gear.

At the moment of the start of switching, the teeth of the engaging wheels have a very small length of the contact line, and the switching is accompanied by strikes due to the discrete nature of the change in the number of teeth of the wheels of the block. This leads to large stresses at the ends of the teeth, therefore the edge of the variator is quickly destroyed.

In addition, to ensure switching, the surfaces on the conical block are arranged in a spiral with a pitch equal to half the width of the gear rims. This leads to an increase in block length by half.

The aim of the invention is to increase the durability of the variator and

0 reduction of its dimensions.

The goal is achieved by the fact that the cylindrical gear wheel is made up of individual sectors, on the hub of each of which a groove is made, the control mechanism is a shaft, parallel to the leader, and fixed on it along a helical line with a step equal to the width of the conical wheel,

0 bars with rollers interacting with grooves, the width of which in their middle part is larger than the diameter of the roller by the amount of the guaranteed clearance, and the width of the grooves at their ends

5 more than the width of the middle part to double the width of the bevel wheel.

In addition, the variator is equipped with a reading mechanism for fixing the angle of rotation of the shaft of the controlling mechanism.

FIG. 1 shows a gear variator, a general VIEW} in FIG. 2 shows section A-A in FIG. one; in fig. 3 is one of the sectors constituting the spur gear.

The variator contains a shaft 1, a block 2 of bevel wheels 3, rigidly mounted on shaft 1, a driving nicked shaft 4 / a cylindrical gear moving along it 5 and a control mechanism b.

The cylindrical gear wheel is made up of individual sectors 7. The number of its teeth is a multiple of the number of sectors comprising it. On the hub 8 of each sector, a groove 9 is made (FIG. 3). The sectors are connected together with the rings 10 (figure 1), which cover them, from antifriction material.

The control mechanism 6 consists of a shaft 11 and fastened thereto along a helical line with a pitch equal to the width of the bevel wheel 3, rods 1 with rollers 13 interacting with the slots 9 of sectors 7. Width a (Fig. 3) of the middle part of each groove 9 dl free entry of roller 13 into it is greater than the diameter of the roller by the amount of the guaranteed clearance. The width at the end of the groove is greater than the width a by twice the width of the conical wheel 3. The shaft 11 of the control mechanism is driven from the servo drive (not shown) through the safety coupling 14 (Fig. 1) and through the gear 15 is connected. the calculating mechanism 16. The gear variator works in the following manner.

When the shaft 11 is rotated with the rods 12, the roller 13, interacting with the lateral sides 17 (FIG. 3) of the grooves 9 of the sectors 7, moves them axially by one pitch of the helix, equal to the width of the conical wheel 3, until all the sectors the components of the gear wheel 5 are not placed in the new position on the shaft 4 without axial shift relative to each other.

If roller 13 misses the groove. 9 and the rotation of the shaft 11 does not occur, the safety clutch 14 tightens and the shaft 11 remains stationary until the next sector approaches the roller 13. Control

operation of the control mechanism 6 is carried out by a counting mechanism 16.

In the proposed gear variator movement of the sectors occurs outside the area of power contact of the wheels, which leads to increased efficiency and reduced wear of the teeth of the splines. The wheels are engaged immediately along the entire length of the teeth. In this way, the longevity of the teeth is greatly improved, and by eliminating the cutting of the teeth along a helical line, the length of the block of the bevel gears is reduced by approximately two times.

Claims (2)

1. A gear variator, containing a driven shaft, a cone-wheel block mounted on it, a drive shaft mounted on the block forming the block, a cylindrical gear wheel mounted on it with axial displacement with a hub and a control mechanism acting on this wheel, characterized in that In order to increase the durability of the variator and reduce its dimensions, the spur gear is made of individual sectors, a groove is made on the hub of each of which, the control mechanism is ale parallel to the leader and fixed on it along a helical line with a pitch equal to the width of the tapered wheel, rods with rollers interacting with grooves whose width in the middle part is larger than the roller diameter by the size of the guaranteed clearance, and the width of the slots at their ends is greater than the width of the middle parts to double the width of the bevel gear. 2. A variator according to claim 1, in which it is provided with a reading mechanism for fixing the angle of rotation of the shaft of the control mechanism. Sources of information taken into account in the examination 1. Pronin B. А. and Revkov G. А. Stepless V-belt and friction gears, M., Mashinostroenie, 1967, p. 221-224.