CN104533984A - Overrun clutch based on expanded-ring type flexible body friction mathematic model - Google Patents

Abstract

The embodiment of the invention discloses an overrun clutch based on an expanded-ring type flexible body friction mathematic model. The overrun clutch comprises an outer ring, a flexible ring, a control lever and a core shaft, wherein the flexible ring is arranged between the outer ring and the core shaft, the inner diameter of the flexible ring is equal to the outer diameter of the core shaft, the outer diameter of the flexible ring is equal to the inner diameter of the outer ring, one side of the control lever is arranged in a groove of the core shaft, and the other side of the control lever is arranged in a groove of the flexible ring. The expanded-ring type flexible body friction mathematic model is F<2>=F<1>e<fa>+(e<fa>-1)qv<2>, wherein F<1> denotes the interaction force between the left end of the flexible ring and the control lever, F<2> denotes the interaction force between the right end of the flexible ring and the control lever, f denotes the static friction coefficient between the flexible ring and the core shaft, a denotes the wrap angle, q denotes the weight per unit length of the flexible ring, and v denotes the linear speed of the flexible ring. By means of the overrun clutch, self locking of the overrun clutch is not limited by the work rotating speed.

Description

Based on the free wheel device of ring expansion formula flexible body friction mathematical model

Technical field

The present invention relates to technical field of mechanical transmission, particularly relate to a kind of free wheel device based on ring expansion formula flexible body friction mathematical model.

Background technique

Free wheel device, is generally used for the transmission realizing power between driving shaft and driven shaft, and according to the difference of relative velocity between driving shaft and driven shaft to realize engaging or surmounting.At present, a class free wheel device based on classic flexible body tribology principle is that free wheel device manufactures and designs and provides new method, and the mechanical property of the free wheel devicees such as counter ball formula, wedge block type has a distinct increment, common free wheel device has the types such as flexible loop surface contact type overrun clutch, chain ring type overrunning clutch and differential and double brake slipper formula overdrive clutch, and above-mentioned free wheel device based on mathematical model be classic flexible body friction Euler's formula.

In the prior art, the free wheel device being theoretical foundation with classic flexible body tribology principle, does not consider the effect of centrifugal force, with flexible body friction Euler's formula F ₂=F ₁e ^{f α}for its mathematical model; And consider the effect of centrifugal force, the mathematical model set up is as follows: F ₂=F ₁e ^fa-(e ^fa-1) qv ², F in formula ₁and F ₂represent the pulling force suffered by flexible loop two ends of free wheel device respectively; E represents nature coefficient; F represents the static friction coefficient between flexible loop and mandrel; A represents cornerite; Q represents the weight of flexible loop unit length; V represents the linear velocity of flexible loop.

Due to the free wheel device self-locking based on this model will be made, need meet condition; Due to this free wheel device design time usually with as self-locking criterion, and when the rotating speed of free wheel device increases to certain value, will make thus the self-locking of free wheel device was lost efficacy.Visible, the self-locking of the free wheel device that the mathematical model based on classic flexible body friction Euler's formula is set up, by the restriction of working speed etc.

Summary of the invention

Provide a kind of free wheel device based on ring expansion formula flexible body friction mathematical model in the embodiment of the present invention, do not limit by rotating speed to make the self-locking of free wheel device.

In order to solve the problems of the technologies described above, the embodiment of the invention discloses following technological scheme:

The invention provides a kind of free wheel device based on ring expansion formula flexible body friction mathematical model, described free wheel device comprises: outer shroud, flexible loop, control lever and mandrel;

Wherein, flexible loop is placed between outer shroud and mandrel, and the internal diameter of flexible loop is equal with the external diameter of mandrel, and the external diameter of flexible loop is equal with the internal diameter of outer shroud;

Controlling lever side is placed in the groove of mandrel, and opposite side is placed in the groove of flexible loop;

Described ring expansion formula flexible body friction mathematical model is F ₂=F ₁e ^fa+ (e ^fa-1) qv ²; Described F ₁represent, the interaction force between the left end of flexible loop and control lever; Described F ₂represent, the interaction force between the right-hand member of flexible loop and control lever; Described f represents, the static friction coefficient between flexible loop and mandrel; Described a represents, cornerite; Described q represents, the weight of unit length flexible loop; Described v represents, the linear velocity of flexible loop.

Preferably, described free wheel device also comprises: retaining ring;

Retaining ring is placed between mandrel and flexible loop, and the internal diameter of retaining ring is equal with the external diameter of mandrel, and external diameter is equal with the internal diameter of flexible loop.

Beneficial effect of the present invention comprises: based on ring expansion formula flexible body friction mathematical model F ₂=F ₁e ^fa+ (e ^fa-1) qv ²the free wheel device set up, make this free wheel device self-locking, need meet condition; Along with the rising of free wheel device rotating speed, on the right of inequality increasing and just be, therefore when designing free wheel device, need to meet this condition, inequality to set up all the time.Therefore visible, the free wheel device set up based on ring expansion formula flexible body friction mathematical model will no longer be subject to the restriction of rotating speed.

Accompanying drawing explanation

In order to be illustrated more clearly in the embodiment of the present invention or technological scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, for those of ordinary skills, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.

One sectional drawing of the free wheel device based on ring expansion formula flexible body friction mathematical model that Fig. 1 provides for the embodiment of the present application;

The schematic diagram of the ring expansion formula flexible body friction physical model that Fig. 2 provides for the embodiment of the present application;

The stressed schematic diagram of free wheel device flexible loop groove in the prior art that Fig. 3 provides for the embodiment of the present application;

The stressed schematic diagram of the flexible loop groove of the free wheel device based on ring expansion formula flexible body friction mathematical model that Fig. 4 provides for the embodiment of the present application;

Another sectional drawing of the free wheel device based on ring expansion formula flexible body friction mathematical model that Fig. 5 provides for the embodiment of the present application;

Fig. 6 is the stressed schematic diagram controlling lever.

Embodiment

Technological scheme in the present invention is understood better in order to make those skilled in the art person, below in conjunction with the accompanying drawing in the embodiment of the present invention, technological scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, should belong to the scope of protection of the invention.

The invention provides a kind of free wheel device based on ring expansion formula flexible body friction mathematical model, as shown in Figure 1, at least comprise: outer shroud 1, flexible loop 2, control lever 3 and mandrel 4;

Wherein, flexible loop 2 is placed between outer shroud 1 and mandrel 4, and the internal diameter of flexible loop 2 is equal with the external diameter of mandrel 4, and the external diameter of flexible loop 2 is equal with the internal diameter of outer shroud 1;

Controlling lever 3 one is placed in the groove of mandrel 4, and opposite side is placed in the groove of flexible loop 2;

In the embodiment of the present application, mandrel 4 is input shaft, when mandrel 4 rotates along direction as shown in Figure 1, drive is controlled lever 3 and compresses with flexible loop 2 liang of end in contact by mandrel 4, flexible loop 2 expands outwardly and compresses with outer shroud 1, and flexible loop 2 self-locking, free wheel device is in jointing state.And when mandrel 4 rotates backward or outer shroud 1 rotating speed is greater than the rotating speed of mandrel 4, flexible loop 2 and outer shroud 1 are thrown off, free wheel device is in and surmounts state.

The embodiment of the present invention based on ring expansion formula flexible body friction physical model, as shown in Figure 2 (in Fig. 2,1 refer to outer shroud, 2 refer to flexible loop); Suppose that flexible loop 2 is at pressure F ₁and F ₂effect under be close to outer shroud inwall, and F ₂> F ₁.Get infinitesimal dl to analyze, when infinitesimal dl is in the threshold state of skidding, represent the positive pressure of outer shroud to this section with dN, dc represents the centrifugal force of this section.The pressure of infinitesimal dl one end is F, and the pressure of the other end is F+dF, and frictional force is F _f=fdN, centrifugal force dc=qv ²d α, can obtain statics balance equation:

$\mathrm{dN}=F\sin \frac{\mathrm{d\&alpha;}}{2}+(F+\mathrm{dF})\sin \frac{\mathrm{d\&alpha;}}{2}+\mathrm{dc};\mathrm{fdN}+F\cos \frac{\mathrm{d\&alpha;}}{2}=(F+\mathrm{dF})\cos \frac{\mathrm{d\&alpha;}}{2};$

From limit theory: $\underset{\mathrm{d\&alpha;}\&RightArrow;0}{\lim }\cos \frac{\mathrm{d\&alpha;}}{2}=1,\underset{\mathrm{d\&alpha;}\&RightArrow;0}{\lim }\sin \frac{\mathrm{d\&alpha;}}{2}=\underset{\mathrm{d\&alpha;}\&RightArrow;0}{\lim }\frac{\mathrm{d\&alpha;}}{2},$ Omit second order trace can obtain: $\mathrm{fd\&alpha;}=\frac{\mathrm{dF}}{F+q{v}^2};$

To above formula both sides integration ring expansion formula flexible body friction Euler's formula: F can be obtained ₂=F ₁e ^fa+ (e ^fa-1) qv ²; As long as F is described ₁and F ₂meet Euler's formula, namely time, can not there is relative sliding in flexible loop 2 and outer shroud 1, namely free wheel device can realize self-locking.

In the embodiment of the present application, the ring expansion formula flexible body friction physical model shown in Fig. 2 is solved, following ring expansion formula flexible body friction mathematical model: F can be obtained ₂=F ₁e ^{f α}+ (e ^{f α}-1) qv ²; Wherein, F ₁represent, the interaction force between the left end of flexible loop 2 and control lever 3; F ₂represent, the interaction force between the right-hand member of flexible loop 2 and control lever 3; F represents, the static friction coefficient between flexible loop 2 and mandrel 4; A represents, cornerite, the central angle that namely flexible loop 2 is right with mandrel 4 contact arc; Q represents, the weight of unit length flexible loop 2; V represents, the linear velocity of flexible loop 2.In the embodiment of the present application, as shown in Figure 6, analyze control lever 3, it is one or three power components as seen, has: F when threshold state ₂l ₂=F ₁l ₁if control the structure factor K=L of lever 3 ¹/ L ₂, then K=L is had ¹/ L ₂=F ²/ F ₁, simultaneous can obtain: K≤e ^{2 π f}(α ≈ 2 π), thus its self-locking criterion is converted into lever construction factor K≤e ^{2 π f}.

From above-mentioned mathematical model, make, based on the free wheel device self-locking designed by this mathematical model, need meet condition.Due to the rising along with free wheel device rotating speed, on the right of its inequality increase and be just, therefore, the free wheel device designed based on this model only need meet condition, its inequality to set up all the time, therefore visible, based on its self-locking of free wheel device of this model design no longer by the restriction of speed, namely with for self-locking criterion.

It should be noted that, because flexible loop 2 is general thinner, therefore the weak link of free wheel device is generally flexible loop 2.If ignore the impact of flexural stress on flexible loop 2, then the stress σ suffered by flexible loop 2 can approximate representation be F ₁and F ₂the stress σ produced _lwith the centrifugal stress σ that centrifugal force produces _c, i.e. σ ≈ σ _l+ σ _c;

In the prior art, the σ of the free wheel device set up based on classic flexible body friction Euler's formula _land σ _call show as tensile stress; And in this application, based on the free wheel device constructed by ring expansion formula flexible body friction mathematical model, σ _lshow as pressure stress, σ _cshow as tensile stress, therefore both can offset a part of stress, the stress state of flexible loop 2 is improved.

Due to, the modal failure mode of free wheel device of the prior art is the fracture of flexible loop groove, carry out analysis to it can find, the stress at the flexible loop groove two ends of free wheel device of the prior art is tensile stress, as shown in Figure 3, the weak link of visible flexible loop groove is narrower place, groove edge to stressing conditions.

And the free wheel device in the embodiment of the present application is analyzed, the stressing conditions of its flexible loop groove, as shown in Figure 4, the edge of the flexible loop groove of the free wheel device in visible the embodiment of the present application is no longer its weak link.Therefore visible, when consistent size, the bearing capacity of the flexible loop of the free wheel device of the application is stronger.

In the another possible embodiments of the application, as shown in Figure 5, the free wheel device in above-mentioned all embodiments also comprises: retaining ring 5;

Wherein, retaining ring 5 is placed between mandrel 4 and flexible loop 2, and the internal diameter of retaining ring 5 is equal with the external diameter of mandrel 4, and the external diameter of retaining ring 5 is equal with the internal diameter of flexible loop 2.

In the embodiment of the present application, flexible loop 2 and outer shroud 1 can be transition fit, and flexible loop 2 and retaining ring 5 can be Spielpassung; Retaining ring 5 and mandrel 4 can be Spielpassung; Flexible loop 2 groove contacts with control lever 3 both ends of the surface.

By increasing retaining ring 5 in free wheel device, the assembling of free wheel device can be facilitated, reducing the wearing and tearing of mandrel 4.

The above is only the specific embodiment of the present invention, those skilled in the art is understood or realizes the present invention.To be apparent to one skilled in the art to the multiple amendment of these embodiments, General Principle as defined herein can without departing from the spirit or scope of the present invention, realize in other embodiments.Therefore, the present invention can not be restricted to these embodiments shown in this article, but will meet the widest scope consistent with principle disclosed herein and features of novelty.

Claims (2)

1. based on a free wheel device for ring expansion formula flexible body friction mathematical model, it is characterized in that, described free wheel device comprises: outer shroud (1), flexible loop (2), control lever (3) and mandrel (4);

Wherein, flexible loop (2) is placed between outer shroud (1) and mandrel (4), and the internal diameter of flexible loop (2) is equal with the external diameter of mandrel (4), the external diameter of flexible loop (2) is equal with the internal diameter of outer shroud (1);

Controlling lever (3) is placed in the groove of mandrel (4), and opposite side is placed in the groove of flexible loop (2);

Described ring expansion formula flexible body friction mathematical model is F ₂=F ₁e ^fa+ (e ^fa-1) qv ²; Described F ₁represent, the interaction force between the left end of flexible loop (2) and control lever (3); Described F ₂represent, the interaction force between the right-hand member of flexible loop (2) and control lever (3); Described f represents, the static friction coefficient between flexible loop (2) and mandrel (4); Described a represents, cornerite; Described q represents, the weight of unit length flexible loop (2); Described v represents, the linear velocity of flexible loop (2).

2. free wheel device according to claim 1, is characterized in that, also comprises: retaining ring (5);

Retaining ring (5) is placed between mandrel (4) and flexible loop (2), and the internal diameter of retaining ring (5) is equal with the external diameter of mandrel (4), and external diameter is equal with the internal diameter of flexible loop (2).