CN2035820U

CN2035820U - Automatic mechanical-control friction stepless speed changing device

Info

Publication number: CN2035820U
Application number: CN 88209868
Authority: CN
Inventors: 余茂芃; 田颐耕
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-08-18
Filing date: 1988-08-18
Publication date: 1989-04-12

Abstract

The utility model discloses an automatic mechanical-control friction stepless speed changing device, comprising an input shaft, an output shaft, a 3K planetary circulation conical shape friction mechanism, a ball bearing (pin roller bearing) shape press mechanism and a cam shape automatic speed regulation mechanism whose 'force closed ' is spring force. The automatic mechanical-control friction stepless speed changing device can output rotational speed with automatic regulation according the needed output character. The utility model has the advantages of long service life, high efficiency, convenient installation, low cost, low output maximum rotational speed, simplicity and compactness.

Description

Automatic mechanical-control friction stepless speed changing device

The utility model belongs to towing gear (TRACTION DRIVE).

The speed of friction stepless gearbox is controlled (hereinafter to be referred as " automatic control ") automatically and is adopted electric mostly, seldom adopts mechanical type.The former is by certain detection system and electric loop, and the rate signal or the force signal of output member fed back to servomotor, and the adjust system of regulating speed changer by servomotor is to reach required speed controlling.The latter passes to the spring system that is mated with certain linkage mechanism with the force signal of output member, the variation by spring force during work, with the speed governing element regulation to the speed governing position of necessity, to obtain required output speed.Though these structures respectively possess some good points, the former complexity, valency height, volume are bigger, and latter's structure is still compact inadequately.

For obtaining a kind of simple, inexpensive, compact structure and can be according to the speed changer of output torque automatic speed regulation, the utility model then is between the output shaft of the speed governing element of friction pair and speed changer, connected a cam mechanism with spring masterpiece " force-closed ", by designing suitable cam profile, output torque (force signal) cam thrust force that is caused and the thrust of spring are balanced each other, thereby with the speed governing element regulation of friction pair to position, to reach force signal self-shifting purpose according to output corresponding to this output torque.

The utility model is owing to adopt cam mechanism to rely on feedback to carry out the automatic control speed governing, cam mechanism can be designed to output shaft and friction pair in speed governing element coaxial line install, so simple in structure, compact, cheap.

In addition, known 3K(annotates: 3K i.e. 3 central gears) the planetary cone wheel geometrical shape of planet circular cone type friction stepless gearbox is unreasonable, and the synthetic curvature of its planetary cone wheel-central gear contacting point is bigger, thereby the contact stress that should locate is higher, it is bigger to slide for how much, and the life-span is shorter, and efficient is lower.Maximum output speed is higher simultaneously, can not adapt to most users' the lower usage requirement of maximum output speed.So lower speed changer of maximum output speed for a kind of long-service life high-efficiency is provided, the maximum diameter that the utility model then is designed to the maximum outside diameter of 3K planet circular cone type friction stepless gearbox planetary cone wheel concave arc turning surface to take turns with this outer cone equates, and the inner cone of planetary cone wheel is arranged on the bottom of concave arc turning surface, so the synthetic curvature of planetary cone wheel of the present utility model-central gear contacting point is less, thereby its contact stress slides less with how much, life-span is longer, efficient is higher, and maximum output speed is lower.

The utility model comprises: input shaft, output shaft, 3K planet circular cone type slip gear, ball type (or roller type) pressurizing mechanism and with the cammingly automatic speed regulation mechanism of spring masterpiece " force-closed ".

Below by accompanying drawing, the utility model detail is further described.

Fig. 1 is the longitudinal sectional view of mechanical automatic control friction stepless gearbox.

Fig. 2 is that the cam profile of cylindrical cam 12 launches and roller axle center free-body diagram.

Fig. 3 is the free-body diagram of output ring 7-collar 8-bearing pin 9-central ring 10-roller axle 11 systems.

Fig. 4 is the A-A sectional drawing of Fig. 1.

Fig. 1 is the utility model embodiment's a longitudinal sectional view, and it is an automatic speed regulation 3K planet circular cone type friction stepless gearbox of doing force feedback with cam mechanism.The input shaft 3 of speed changer borrows the axle 2 of key and motor 1 to link, central gear 6 is fixing, and power is seen Fig. 4 by input shaft 3 footpath central gears 4, planetary cone wheel group 5, speed ring 7, the collar 8, axle 9(), central ring 10, roller finger 11, cylindrical cam 12, pressurizing mechanism 13 pass to output shaft 14.Being splined between input shaft 3 and the central gear 4, is key connecting between pressurization disk 13a and the output shaft 14, and the speed ring 7 and the collar 8 are interference fit joint between axle 9 and central ring 10 and cylindrical cam 12 and the pressurization disk 13b.The impacting force of each surface of contact is provided by roller pressurizing mechanism 13 between

central gear

4,6,7 and the planetary gear set.Belleville spring 17 is used to provide precompression.During work, the automatic speed regulation principle is as follows: output ring 7 is transmitting the output torque to this section transmission of power line of output shaft 14, so as shown in Figure 2, under the situation that each element physical dimension has been drafted, if the output torque is T arbitrarily, then the corresponding peripheral force at place, roller axle 11 roller axle center is Ft, if disregard frictional force, then the normal on the pitch curve 12a that drafts of normal force Fn Ying Yuyi herein is consistent, so can obtain corresponding axial force F a thus, in view of the above, get and decide spring 15, and its corresponding thrust is equated with it, then the output ring 7, the collar 8, bearing pin 9, central ring 10, the system that roller axle 11 is formed just is in state of equilibrium as shown in Figure 3, promptly output ring 7 can be in a certain axial position under the adjusting of spring force, thereby has the output speed corresponding to this position.For example, desire is done permanent power output, promptly desiring to make the output torque T of output ring 7 and the long-pending permanent of output speed n is normal value, then a corresponding output torque T should be arranged corresponding to arbitrary output speed n, as drafting the working diameter of cylindrical cam 12, can obtain corresponding Ft, as getting the thrust Fa that decides spring 15 again, then by the i.e. Fn=Ft+Fa as can be known of Fig. 2, thereby can obtain the normal of required pitch curve 12a and the tangent line perpendicular, and then can obtain required pitch curve 12a with it.In like manner, as the working diameter that provides cylindrical cam 12 and the size (being known its thrust Fa) of spring 15, also can obtain corresponding to permanent torque output or the pitch curve 12a when becoming power and becoming torque output.

The maximum outside diameter 5a of planetary cone wheel 5 concave arc turning surface of the present utility model is designed to take turns the outer cone maximum diameter with this and equates, and inner cone 5b(sees the B portion of Fig. 1) be arranged on the bottom of concave arc turning surface, so the time concave arc turning surface have the maximum radius of clean-up, the composite curve radius of itself and central gear 4 contacting points is bigger.Moreover, this moment, central gear 6 contacted with inner cone 5b, rather than and plane contact, so its composite curve radius also (is annotated: when making above conclusion than the latter is big, considered the corresponding influence that reduces of

central gear

4,6 diameters that is caused because of concave arc turning surface bottom), thereby also just reduced the contact stress of described each contacting point, and the contact stress reduction just might make area of contact reduce, therefore by suitably reducing contact stress and suitably reducing area of contact, can improve the life-span and can reduce by how much slips and the raising transmission efficiency.Moreover motion calculation also shows, adopts the planetary cone wheel of described geometrical shape, can also obtain lower maximum output speed.

In addition, for can automatic speed changing on certain power section, as shown in Figure 1, in the present embodiment, the thrust Fa that can temporarily transfer 16 pairs of springs 15 of joint nut does suitable adjusting, thereby can utilize the automatic speed regulation under new output power of original cam profile.

Fig. 4 is the AA sectional drawing of Fig. 1, the figure shows and can make output ring 7(see Fig. 1) the unsteady collar 8 connects with the crosshead between the cylindrical cam 12: a central ring 10 is arranged between the collar 8 and the cylindrical cam 12, be fixed with a pair of bearing pin 9 and a pair of roller axle 11 perpendicular on the central ring 10 with it, the other end of bearing pin 9 and the collar 8 are movingly, the working profile of the roller of roller axle 11 and cylindrical cam 12 movingly, the outer rim of central ring 10 is that spherical (see figure 1) inner edge longitudinal section is the dome arc.The effect that crosshead connects is identical with the effect of universal joint, can make output ring 7 free floating on planetary cone wheel group 5, avoids or reduce the interference of output system manufacturing alignment error.

Claims

1, a kind of mechanical automatic control friction stepless gearbox comprises input shaft, output shaft, 3K planet circular cone type slip gear, ball type (or roller type) pressurizing mechanism and with the cammingly automatic speed regulation mechanism of spring masterpiece " force-closed ", it is characterized in that:

1. the cam mechanism that between the output shaft of the speed governing element of friction pair and speed changer, has connected a spring masterpiece " force-closed ", by designing suitable cam profile output torque (force signal) cam thrust force that is caused and the thrust of spring are balanced each other, with the speed governing element regulation in the friction pair to corresponding to this output torque the position on, with reach according to output force signal self-shifting purpose;

2. the planetary cone wheel concave arc turning surface maximum outside diameter of the speed changer maximum diameter that is designed to take turns with this outer cone equates, and the inner cone of planetary cone wheel is arranged on the bottom of concave arc turning surface.

2, according to the described mechanical automatic control friction stepless gearbox of claim 1, wherein, described spring thrust can be temporarily transferred the joint nut and be done suitable adjusting.

3, according to the described mechanical automatic control friction stepless gearbox of claim 1, the wherein said collar adopts crosshead to connect with the cylindrical cam connection place.