WO1999046519A1

WO1999046519A1 - Dynamic transmitter of the torque moment

Info

Publication number: WO1999046519A1
Application number: PCT/SK1999/000003
Authority: WO
Inventors: Július S^¿VARAL
Original assignee: Svaral Julius
Priority date: 1998-03-09
Filing date: 1999-03-09
Publication date: 1999-09-16
Also published as: SK31698A3; AU3284899A

Abstract

The dynamic transmission of the torque moment consists of the box (1), the inner cross-sectional area of which is formed by a smooth closed curve with a continously changing radius in respect to its central axis, having at least one rotatably mounted roller (2) mechanically linked with a degree of freedom in radial direction with the carrier (5) receiving a torque moment input, the box (1) being connected with the torque moment output. The device may find a wide application especially in cars, motorcycles, working machines, tractors, industrial machines drive, etc.

Description

Dynamic Transmitter of the Torque Moment

Technical Field

The technical solution concerns the dynamic transmitter of the torque moment with a continuous change of moment and at the same time the speed ratio of the input and output shafts is being changed continuously.

Background Art Using the dynamic transmitter of the torque moment in working machines is generally known and brings about a lot of advantages. This is especially automatic adaptation of the tractive effort and the motion speed to the working resistance of machine, motor protection from overloads, reduction of dynamic loads by torsional vibrations in the transmitting parts, assuring stepless machine start, making attendance easier due to reduction of the number of control operations, obtaining a larger regulation range, etc. These advantages, however, are accompanied by significant cost increase and reduction of the overall transmission efficiency. Various constructions of dynamic transmissions of the torque moment are known. The hydrodynamic transmission of the torque moment is the most known construction. It is filled with a working liquid and consists of a pump wheel and a turbine wheel and a distributor (reactor) . The distributor as a reaction element catches inertial forces from the liquid mass and induces the reaction moment. If the turbine wheel rotates more slowly than the pump wheel, a moment of the opposite sense acts on the distributor than on the turbine. The distributor has a tendency to rotate in the opposite sense than the turbine, which is however hindered by its firm connection with the machine frame. Due to this fact the moment on the turbine wheel is increased and it reaches the maximum value when the turbine stands (i. e. when also the machine stands) . Then the driving moment is changed continuously according to the load on the turbine wheel. This fact enables automatic adaptation of the moment to the size of the working resistance and it is applied especially at starts and overloads. Its disadvantage lies in a lower efficiency caused by hydraulic losses in the system. The maximum efficiency of hydrodynamic transmissions reaches 0.7 up to 0.89, such efficiencies being obtained only within a very narrow range of the operational parameters.

The device according to the patent CS 212800 with a hydrostatic transmission of the torque moment is very intricate and costly from the viewpoint of design. Also other systems of transmissions of the torque moment are designed on a mechanical principle. Mostly the problem is solved by a centrifugal friction clutch and centrifugal controlled epicyclic gearing. For instance, according to CS AO 206323 the system of transmission is solved in such a way. This solution however is rather designed only for transmission of low power. The technical solution of the gearbox with continuous change of the speed ratio according to CS AO 177291 is based on a similar principle. The gearbox is based on the planet principle with centrifugal regulation friction elements. The main defect of this device lies in its low operational life and reliability owing to use of permanently working centrifugal elements and relatively high production costs required by manufacture of the planet gearing.

The devices, which use a variator to change the ratio of the input and output torque moments, have a low efficiency, high noisiness, short working life and high production costs.

The device according to the patent CS 276048 "Trochoid rolling reductor" requires a very precise manufacture; it is designed mainly for the field of robotics and automation to transmit high speed ratios.

Disclosure of Invention

Shortcomings mentioned are significantly eliminated by the dynamic transmission of the torque moment according to this technical solution. Its essence lies in the fact that it is formed by a box, its internal area in the cross section being formed by a closed smooth curve the radius of which from the central axis is being changed continuously. The smooth curve can be represented e.g. by an oval, an ellipse, an n- angle (with rounded vertices where the n > = 3), cam, complex cam, etc. The figures which form the box cross section can be performed with straight, concave or convex sides. At least one rotationally mounted roller is rolling on the inner box area, the roller being mechanically connected with a carrier and this connection has a degree of freedom in the radial direction. So radial motion of the roller is enabled as well as its revolution around its own axis. The carrier is connected with the torque moment input, advantageously with the input shaft and the box is connected with the torque moment output, advantageously with the output shaft.

The carrier is driven by the input torque moment with revolutions "n" together with rolling rollers which are mechanically linked with it. So the rollers are thrusted by the centrifugal force onto the box inner area on which they are rolling.

The kind and form of the curve being formed by the box cross section and the number of rollers are chosen depending on the characteristic of the torque moment transmission required to be obtained. It depends mainly on the shape of the curve forming the box cross section which in case of different input and output revolutions creates a roller centripetal acceleration and so also the reaction of the centripetal force acting onto the box inner area; on the size of the roller centrifugal force acting onto the box inner area; on friction between the roller and the box inner area and on the number of rollers and their mass. The partial tangential force acting onto the box inner area is a component of the forces and it creates the output partial torque moment on the momentary arm. The resulting momentary tangential force is then the sum of momentary partial tangential forces and the resulting torque moment is given by the product of momentary partial tangential forces and the momentary arms onto which the forces are acting. The mechanical connection of the carrier with the rollers can be implemented by various ways e.g. by swing arms, telescopic arms, guiding slots in the carrier, etc.

It is advantageous if the number of rollers is two and more and their axes are located in grooves which are formed in side covers, the groove inner area being equidistant with the shape of the box inner area. So uniform roller thrust onto the box inner area is obtained and in case of higher revolutions the rollers do not rebound from the box inner area. A similar effect can be obtained e.g. by means of a radial spring thrust or by a spring having a damping element eventually by a hydraulic, pneumatic or mechanical thrusting element with a programmable characteristic.

Then the starting characteristic of the transmission also depends on the direction and shape of the guiding grooves in the carrier possibly on the size of the swing arms or on the characteristic of the thrusting elements.

The general characteristic can be found in Fig. 4. The transmission reaches the maximal torque moment at maximum input and zero output revolutions when centripetal forces are formed from centripetal acceleration of the rollers as well as when centrifugal forces from maximum revolutions are the highest ones. However the transmission also at the same revolutions on the input and output transmits the nominal basic torque moment derived from the rollers centrifugal force acting onto the box area. Its tangential component induces the basic nominal torque moment.

It is evident that the dynamic transmission of the torque moment according to this technical solution can be designed - with the input and output shafts, - with the input shaft and the output through a box (e.g. by gearing), - with the input through a side guide (e.g. by gearing) and output shaft, - with the input through a side guide and output through a box.

Compared with the mechanical dynamic transmissions known hitherto the dynamic transmission according to this technical solution has a series of advantages. This is, above all, a simple construction, which does not require increased accuracy of manufacture. Another advantage lies in its reliability and low wear, as this solution has no friction elements. The working elements have only a rolling resistance and therefore the efficiency is high, comparable with traditional manual mechanical gearboxes.

Compared with a hydrodynamic transmission the main advantage is found especially in its high efficiency and better characteristic, as the hydrodynamic transducer must work with sliding. When the input and output revolutions are equal it transmits no torque moment. But the dynamic transmission according to this technical solution transmits the nominal torque moment derived from the centrifugal force of the rollers even in case of equal input and output revolutions. Moreover in case of an opposite drive certain structures according to this solution have reversing features i.e. they transmit the torque moment also from the side of output to the input which is important e.g. in case of utilization in cars when braking by means of the engine.

Brief Deskription of Drawings

Fig. 1 illustrates the construction of the dynamic transmission with a mechanical linkage of the carrier and rollers by means of a guiding groove. Fig. 2 schematically illustrates the dynamic transmission with linkage of the carrier and rollers by means of a telescopic element. The Fig. 3 is a schematic illustration of the dynamic transmission with linkage of the carrier and rollers by means of swing arms. The Fig. 4 represents typical momentum characteristics of the dynamic transducer.

Modes for Carring Out the Invention

Example 1 - Best Modes for Carring Out the Invention The dynamic transmission according to Fig. 1 consists of the box 1_, the inner area of which in its cross section has a form of a square with rounded vertices onto which continuous rolling of the rollers 2 is assured. The side covers _4 and 7_ in which bearings 1_2 and 1_3 are located for rotary mounting of the input shaft 3_, are screwed onto the box body by screws 1CJ and nuts 1_1. On the input shaft 3_ passing through the cover 4_ the carrier 5_ is firmly mounted, in which the guiding grooves 14 to guide the axes _9 of the rollers 2_ are formed. The shaft ends forming the axes 9_^ are freely mounted in the grooves 15 formed in the side covers 4_ and 1_. The grooves 15_ assure the position of the axes 19 of the rollers 2_ shafts in a constant distance against the inner area of the box 1_. The output shaft _6 is linked with the output side cover 1_ by means of a feather or a grooved end.

The torque moment of the driving engine which is not illustrated is transmitted onto the input shaft 3_ on which the carrier 5_ is fixed mechanically by means of the guiding grooves 14_, connected with the shafts forming the axes _9 and so also the rollers 2 by means of which due to the effect of the centrifugal force acting on the rollers !2, a bond is created in the spot of contact with the inner box _1 area. If the revolutions of the input shaft _3 compared with the box 1_, are higher, the rollers 2_ roll on the box 1 inner area, and in case of changed radial motion of the rollers 2 , they create a dynamic bond which assures transmission of the torque moment to the output shaft 6. If the revolutions of the input and output shafts are equal, the transmission of the torque moment of the dynamic transducer is implemented only by the centrifugal force acting on the rollers 2 in the space of tops of the box 1_ internal area. The oil filling in the box 1_ provides increased dynamic effect of transmission of the torque moment and lubrication.

Example 2

The dynamic transmission according to Fig. 2 consists of the box 1., the inner area of which in its cross section has a shape of a smooth curve with rounded vertices along which continuous rolling of rollers 2_ is assured. There is a fixedly mounted carrier 5_ on the input shaft 3!' ⁱⁿ which the guiding grooves 14 are formed in which the telescopic guiding elements 16 are inserted and they are thrusted by means of the springs 17. The rollers 2 are rotary mounted in the telescopic guiding elements.

Example 3

The dynamic transmission according to Fig. 2 consists of the box 1 ^the inner area of which in its cross section has a shape of a smooth curve with rounded vertices along which continuous rolling of rollers 2_ is assured. On the input shaft 3_^ there is a fixedly mounted carrier _5 with which the arms 1^ are linked in a swivel way, thrusted by means of the springs 17. The rollers 2_ are rotary mounted in the arms 18.

Industrial Applicability The dynamic transmission can be industrially manufactured in mechanical engineering enterprises equipped with suitable machines and it can be used in such machines where continuous start and continuous change of revolutions and of the torque moment depending on load are required. It can find a wide application especially in cars, motorcycles, working machines, tractors, industrial machines drive, etc. In connection with an asynchronous motor the performance of such assembly comes close to the performance of the DC motor.

Claims

1. The dynamic transmission of the torque moment characterized by the fact that it consists of the box (1), the inner area of which in its cross section is formed by a closed smooth curve, the radius of which from the central axis is changing in a continuous manner, and of at least one rotary mounted roller (2), its mechanical linkage with the carrier (5) being formed with a degree of freedom in the radial direction, and the carrier (5) is connected with the torque moment input, and the box (1) is connected with the torque moment output .

2. The dynamic transmission of the torque moment according to the claim 1, characterized by the fact that the mechanical linkage of the carrier (5) and the roller (2) is realized by means of the guiding groove (14), in which the roller shaft (2) is freely mounted.

3. The dynamic transmission of the torque moment according to the claim 1, characterized by the fact that the mechanical linkage of the carrier (5) and the roller (2) is realized by means of the guiding groove (14), in which the telescopic element (16) is sliding mounted, in which the roller (2) is rotary mounted.

4. The dynamic transmission of the torque moment according to the claim 1, characterized by the fact that the mechanical linkage of the carrier (5) and the roller (2) is realized by means of the swing arm (18) .

5. The dynamic transmission of the torque moment according to the claims 1, 2, 3 or 4, characterized by the fact that the axes (9) of the rollers (2) are led in the grooves (15), formed in the covers (4, 7) .