RU2468270C1 - Method for stepless variation of motion transfer and device for its realisation - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: method for stepless variation of motion transfer consists in the fact that even rotary motion at the device inlet of stepless variation of motion transfer is converted into two separate movements of equal module, which are then summed. The even rotary motion will be the result of summing up continuous movements. Transfer ratio between master and slave shafts is controlled with a phase shift of two separate continuous movements. For this purpose upper and lower limits of the resulting even rotary motion are used simultaneously. The device for stepless variation of motion transfer comprises an intermediate shaft (6), gears (23, 35) of which engage with differentials (22) and a gear (34) of a slave shaft (4).

EFFECT: expansion of a range of a transfer ratio of a variator.

2 cl, 14 dwg

Description

The invention relates to mechanical engineering. In particular, to stepless gears of movement, which provide a smooth and continuous change in power and kinematic gear ratio.

It is known that gears that provide a smooth, stepless change in the angular velocity of the driven shaft, at a constant angular speed of the drive shaft, are called variators (I.I. Ustyugov. “Machine Details”, “Higher School”, Moscow, 1973, p. 45). CVTs are classified by several main types: frontal, conical, ball, with a ring, with pads, torus, etc. In all of the listed variators, the movement from one shaft to another is transmitted due to friction excited between the working surfaces of the rotating rollers, therefore, such transfers are called friction ones. So, for example, in the frontal variator, the driving and driven rollers touch each other. When the point of contact of the driven roller changes relative to the center of rotation of the driving roller, the circumference (described by the point of the rotating driven roller) increases (decreases). In this case, the angular velocity of the driven shaft also changes. Friction variators have several advantages: simplicity of design and low cost of manufacture, smooth and quiet operation, the possibility of stepless speed regulation; when overloaded, the rollers slip, protecting the drive mechanism from damage. At the same time, all the types of friction variators listed above have inherent disadvantages: the variability of the gear ratio due to slippage of the rollers, limited transmitted power (10-20 kW), high loads on their shafts and bearings (bearings), relatively low efficiency, wear of workers roller surfaces and their heating. Therefore, in mechanical engineering, power transmission based on friction variators are used extremely rarely.

In addition to friction gears in mechanical engineering, belt and chain variators are used. The main structural elements of the chain variator are two pairs of sliding gear cones and an endless chain with sliding plates. Such variators transmit power up to 75 kW, at a peripheral speed of 6-9 m / s. The efficiency of the variator, depending on the gear ratio, varies between 0.85-0.95. The largest range of gear ratio changes is 7. The disadvantage of the variator is the low reliability of the belt and chain, which limits the transmitted power.

Closest to the technical solution to the proposed invention is the variator according to patent RU 2391587 "Method of stepless change of transmission of motion and device for its implementation." The method is based on the principle that the uniform rotational movement at the input of the variator is converted into two separate, but equal in modulus, continuous movements. Then the resulting continuous movements add up. The resulting addition of continuous movements will be uniform rotational motion. The gear ratio between the drive and driven shafts is controlled by the phase shift of two separate continuous movements.

Structurally, the variator includes transforming mechanisms with driving and driven elements making up eccentric pairs, a clip with differentials, a transformation mechanism, driving and driven shafts.

The disadvantage of the technical solution is that it has a limited range of gear ratio D, which is expressed by the formula:

where Vmax and Vmin are the largest and smallest uniform resulting velocity, i.e. the upper and lower limit of the resulting uniform speed obtained on the differential case, α is the angle of shift in one direction or another from the position of the full antiphase of eccentric pairs of converting mechanisms.

The technical task of the invention is to expand the range of the gear ratio of the variator.

To solve this problem, an intermediate shaft has been introduced into the variator design. The intermediate shaft is equipped with gears that mesh with the segments of the differential housings and with the gear of the drive shaft.

The variator device is shown in the drawings.

Figure 1 shows a drawing of the variator in assembled form.

Figure 2 shows the variator with spaced apart parts of the assembly, explaining its composition and the relative position of the main assembly units and components.

Figure 3, 4 shows two main nodes of the transforming mechanism.

Figure 5 shows the transforming mechanism in assembled form.

Figure 6 shows the design of the cage with differentials in assembled form.

Figures 7, 8, 9 and 10 show the construction in two views of an eccentric pair with driven and driven elements in assembled form and with spaced parts of the assembly.

11, 12 and shows the construction of the differential in assembled form and with spaced apart parts of the assembly.

Figure 13 shows the construction of the transformation mechanism assembly.

On Fig shows graphs of obtaining uniform motion from uniformly accelerated and equally slow movements.

The variator includes two converting mechanisms 1, a holder with differentials 2, mounted concentrically between the converting mechanisms, the transformation mechanism 3, the leading 4, the driven 5 and the intermediate 6 shafts.

The converting mechanism is a cage with separators 7, in the cells of which the driving elements 8 and the central gear 9 are installed, and a cage with separators 10, in the cells of which the driven elements 11 are installed. The central gear 9 is engaged with all the driving elements. Both clips of the converting mechanism are combined, with each leading element mating with the driven element, and they make an eccentric pair.

The driving element is a gear 12 with a shaft, on the surface of which a curved corrective groove 13 and a radial groove 14 are made. A reciprocating movement is made in the radial groove, the main carrier 15.

A diametral groove 16 is made on the surface of the driven element, in which the slider 17 moves. The slide is provided with an opening 18 and a carrier 19. On the other hand, the driven element is provided with a spline connection 20.

When pairing the lead and driven element, the main carrier 14 of the driving element 8 enters the hole 18 of the slider 17, and the carrier 19 of the slider 17 enters the correction groove 13 of the driving element 8. The leading and driven elements connected in such a way form eccentric pairs, since the rotation axes leading and driven elements are eccentric. When the driven element rotates, the main carrier 14, approaching and moving away from the rotation axis of the driven element 11, causes accelerated and slowed circular movements of the driven element. In this case, the slider 17 rotates with the driven element, while simultaneously moving along the diametral groove 16. There can be 3 or more in the conversion mechanism of the eccentric pairs. There are five of them in the proposed design.

The ring with differentials is an annular gear 21 with internal gearing, in which differentials 22 are installed, placed around the gear 23 of the intermediate shaft 6. Differentials, as they rotate around their axis, are engaged either with the gear 23 or with the gear of the internal gear 21 of the cage .

The differential includes a housing 24, which is essentially a segment gear with a segment 25, inside which satellites (three bevel gears) are installed in the cell 26. The satellites are mounted on the axles 27 with fasteners 28 and mesh with two bevel gears 29 having spline gears connection 30. Bevel gears are equipped with bearings 31 and fasteners 32, which are mounted on the axis 33 of the housing.

The clip with differentials is designed to transmit input motion and to remove superimposed and slow motion of driven elements of eccentric pairs of converting mechanisms superimposed on each other and transmitting these movements through the internal gear of the driven shaft.

The drive shaft 4 through the gear 34 is connected with the gear 35 of the intermediate shaft 6.

The driven shaft 5 is connected to the internal gear gear 21. The driven elements 11 are connected by splines 20 to the differential gears 29.

The transformation mechanism includes a hydraulic cylinder 36 with a piston 37 and a clutch. The coupling includes bushings 38 and 39. interconnected by a screw connection 41, and scroll relative to each other around a common axis. Central gears 9 of two converting mechanisms are mounted on sleeve 38 and shaft 40. The piston 37 is connected to the sleeve 39, with internal straight slots, which include the splines of the shaft 40. The sleeve of the coupling 39 moves along the shaft 40 along the splines.

The transformation mechanism is designed to change the gear ratio of the variator. The gear ratio is changed by phase displacement of the eccentric pairs of one transforming mechanism relative to the eccentric pairs of another transforming mechanism. A phase shift is created by turning the central gears 9 of the transforming mechanisms 1 relative to each other, which, in turn, connect eccentric pairs. The rotation is carried out by the movement of the sleeve 39 of the coupling along the axis, which is connected by helical engagement with the sleeve 38, on which one of the central gears 9 is mounted, and is connected by straight splines to the shaft 40 with the central gear 9 of the second converting mechanism. The movement is provided by the piston 37 of the hydraulic cylinder 36.

The variator works as follows.

When the drive shaft 4 is rotated, the rotational movement by means of the gear 34 is transmitted to the gear 35 of the intermediate shaft 6. In this case, the gear 23 rotates, with which the segments 25 of the differential housings 24 are sequentially engaged.

With a uniform rotation of the driving elements 8, accelerated and slowed-down movements of the driven elements 11 are caused. The result of superimposing these accelerated movements (provided that these accelerations are counter-directed) will result in a uniform rotation of the differential housing 24. Accordingly, feedback, in the same phase (in which the resulting movement on the differential case was uniform), rotating the differential case 24 through the driven elements 11 evenly, on the driving elements 8 we get uniform movement. Thus, the segments 25 of the differential housing 24, sequentially engaging with the pinion gear 23 of the intermediate shaft, provide continuous uniform rotation of the driving elements. Accordingly, the differential housings, alternately engaging with the gear 23, alternately engage with the internal gear 21, causing continuous rotational movement of the driven shaft 5.

The process of converting superimposed and slow motion superimposed on each other, the result of which is uniform movement, is explained in the graph (Fig. 14). On the graphs, we observe the phases of motion of superimposed accelerated motions, which have an upper and lower limit of uniform motion, 180 ° apart.

When shifting by a certain angle, in the positive side or in the negative side from the position of the antiphase, one transforming mechanism relative to the other, we observe, respectively, the interchange of the upper limit of the phase of the uniform movement of the differential case with the lower limit of the phase of the uniform movement of the differential case.

Accordingly, the interchange of the engagement between the drive and driven shaft limits the uniform rotation of the differential case. That is, if the input movement was transmitted through the lower limit of uniform motion, and the output was shot through the upper limit of uniform motion, then when the phase is shifted, the input motion will be transmitted through the upper limit of uniform motion, and the output will be removed from the lower limit of uniform motion.

If the drive shaft transmits movement through engagement with the lower limit of uniform motion of the differential housing, then the output shaft is meshed with the upper limit of uniform motion of the differential housing. The gear ratio in this case is equal to Vmin / Vmax.

If the drive shaft transmits movement through engagement with the upper limit of uniform motion of the differential housing, then the output shaft is engaged with the lower limit of uniform motion of the differential housing. Accordingly, the gear ratio is Vmax / Vmin.

The range of gear ratio of the variator is characterized by the expression:

That is, introducing an intermediate shaft with gear into the variator design, we achieve a quadratic change in the gear ratio range.

Claims (2)

1. A method of steplessly changing the transmission of motion, in which a uniform rotational movement is converted into two separate, but equal in absolute value, continuous movements that add up to a uniform rotational movement, characterized in that both the upper and lower limits of the resulting are used to expand the range of the gear ratio uniform rotational motion. 2. Device for steplessly changing the transmission of motion, including a housing, a drive shaft with a gear, a driven shaft, converting mechanisms with driving and driven elements making up eccentric pairs, a holder with differentials, a transformation mechanism, characterized in that in the design of the device for continuously variable transmission the motion introduced an intermediate shaft, the gears of which are engaged with differentials and the gear drive shaft.

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