SU1733757A1 - Disk spring - Google Patents

Abstract

Invention m. Used in spring shock absorbers, mechanical energy accumulators, elastic supports and other devices. Making the spring section wedge-shaped and more evenly distributed in the cross section of stresses increases its elasticity, static strength and power consumption. 1 il.

Description

The invention relates to mechanical engineering, in particular to technological, energy, transport machines, and can be used to create spring absorbers, mechanical energy accumulators, elastic supports, power closures, vibrators, impactors, etc.

A known spring is a spring, the annular working body of which has a rectangular cross-section. Spring dimensions (ring thickness, internal diameter, taper) are optimized, which allows to increase the specific strain energy compared to the standard series of springs by 5-8%.

However, the technical characteristics of the specified spring remain limited: the deflection and specific deformation energy are small, the stiffness coefficient is high, the strength is reduced under static loads, which is associated with sharp uneven stresses in the spring body: at the corner points of the rectangular section (see fig.) the ratio is on average as the numbers 1.4: 1: 0.74: 0.44 (the unit represents the maximum stresses that determine fatigue, the strength of the spring, and the number 1.4 is the maximum compressive stresses that determine its static strength.

Closest to the proposed construction, by its technical essence, is a spring spring, the cross section of which has the same rectangular shape, but with chamfers at the corner points A and C and with radius rounded corners at all angles, which somewhat reduce the maximum compressive and reduce stress concentration in the corners.

However, this spring has drawbacks consisting in high spring stiffness and low specific (per unit volume of the body) strain energy arising in connection with a large non-uniformity of stresses in the cross-section of the plate. The stiffness of the spring is also increased by the fact that the forces acting on it are shifted from the angles A and C to the center of gravity of the cross section of the ring, the relative displacements of their points of application are smaller.

The purpose of the invention is to increase the elasticity (deflection) of the spring, its static

SA CO XI SL 4

durability and energy consumption with limited dimensions.

The drawing shows a spring belt, a general view.

The spring has the shape of a cone-shaped ring with a radial cross-section narrowing from the periphery to the axis, the maximum thickness h at the maximum spring diameter D changes into thickness hi at the internal diameter d.

Spring works as follows.

Under the action of the forces P distributed over the internal contour of the spring from above, and the forces Q distributed along its external contour from the bottom, the spring changes its shape so that the BC line approaches the horizontal. Maximum spring deflection

fm (D-d) y / 2,

where y is the angular rotation of the ring section.

Features of the deformation of the wedge-shaped section of the spring in comparison with the rectangular one are as follows.

Stresses at any point of the cross section on the line AB, for example, are determined by the relative elongations of the annular spring fibers passing through these points.

one E Јd; OB-E Ј,

where E is the modulus of the longitudinal elasticity of the material;

E-relative extensions.

But the relative elongations are determined by two factors: the rotation of the point M on the longitudinal axis of the section relative to the center of bend O and the rotation of the line AB relative to the point M.

D

A-g (I ohm (cos p - cos a) +

HA

hi

(“-)).

where a - the initial angle of inclination of the axial line KM section to the horizontal;

p is an arbitrary subsequent angle of inclination of this line to the horizontal.

Usually the second term in the formula is several times the first. With maximum deformation, springs with a rectangular cross section have

 y 0; hi h,

for spring with wedge-shaped section

a y-V / 2; (p -ip / 2; h h

Obviously, the smaller the angle p, the smaller the first term in the formula, and the smaller the thickness hi, the smaller the second term.

Similarly, a formula is obtained for calculating the tensile stresses at point B.

P

OB -t (- IOM (cos (f - cos a) +

15

+ -frL (a-fp)) E.

Here the main gain is also obtained due to the second term. Consequently, at constant h with increasing angle

0 sharply decreases the voltage at points A and

In, and you can increase the angle of the strain.

Calculations show that stress

bending on the surface of the spring body when

increasing 1 /) from zero to h / R

5 smoothly level, the specific energy of deformation and deflection increase, the rigidity decreases. When x = 0.7 h / R, the compressive stress at point A of the spring exceeds the corresponding stress

0 standard spring and angle y must be reduced. It is therefore recommended

(0.7 ... 1) h / R

5 The left limit provides increased energy of the spring with a reduced static strength of OA 1,4, the right limit provides high static strength of OA 0 at a slightly lower total energy. The corner advantage y is maintained.

A more uniform distribution of stresses in the spring body allows one and a half to increase the average specific energy of its deformation, to reduce the size and consumption of material. The reduction of compressive stresses in the region of point A here makes it possible to avoid plastic deformations arising under prolonged static loads.

Claims (1)

0 claims A trailed spring, having the shape of a cone-shaped ring, is characterized in that, in order to increase elasticity, strength and energy intensity, the cone-shaped ring in radial section is a wedge with apex located on the side of a smaller base, and an apex angle selected from the ratio V (oj ... 1) h / r. where R is the radius of the larger base of the cone-shaped ring; h is the maximum thickness of the cone-shaped cross section.