RU1803786C - Stand for testing flexible elements for strength - Google Patents

Abstract

The fatigue test bench for elastic elements relates to mechanical engineering and can be used to test elastic elements, suspension struts, cable terminations, etc. for fatigue. The purpose of the invention is to reduce the energy intensity of the drive used. The stand contains a frame 1, at the ends of which there are fixed adjustable screw supports 2 with nuts 3, to which one of the ends of the tested elastic elements 4 is attached, a drive in the form of an electric motor 5 with a pulley 6, which is connected via a belt 7 to a pulley 8, which sits rigidly on shaft 9, YurGII nti niyu nost. mikroderen in 4, ciedila 9, which is rigidly connected to gear 10, shaft 9 is installed in brackets 11 located on the frame 1. In the middle of the frame 1 there is a shaft of the crank mechanism 12 on bearings at one end of which the gear 14 is rigidly fixed outside the frame 1 which is in engagement with gear 10. A bearing is mounted on the shaft pin of the crank mechanism 12, which enters the rectangular groove of the slider with eyes for fastening the movable ends of the corresponding elastic elements 4. On the axis of the frame 1 a gear wheel 21 in engagement with the wheel 14. A rigid crank 22 is fixed on the wheel 21, which enters the rectangular groove 23 of the slider 24, which is placed in the guides 25 and connected to the power spring 26, the other end of which is fixedly mounted on the frame 1. on the crank 22, a nickname 27 has been inserted, to reduce friction when moving along the groove 23. On top of the frame 1, a cycle counter 28 is fixed. 5 ill. Ј

Description

Figure 1

The invention relates to mechanical engineering and can be used to test elastic elements, suspension struts, cable terminations.

The purpose of the invention is to reduce the energy intensity of the drive used.

The goal is achieved in that in the stand for testing elastic elements for fatigue, containing a frame with a guide, two supports for securing one of the ends of the respective elastic elements, placed in the guide slider with movable supports for attaching the second ends of the respective elastic elements, and. a slider moving drive, including a crank mechanism, the pin of which is connected to the slider, the supports are mounted coaxially and symmetrically with respect to the slider, and the stand is equipped with two gear wheels engaged, one of which is mounted on the crank axis, and the second is mounted on the frame, an additional crank mounted on the second wheel and a power spring, one end of which is connected to the frame, and the other with an additional crank, and the diameter of the first gear is twice the diameter of the second gear of the wheel.

In FIG. 1 shows a proposed rtend, side view; in FIG. 2 - the same, top view; in FIG. 3 is a section AA in FIG. 2 stands through the slider in the position when the slider is maximally shifted to the right; in FIG. 4a is a simplified diagram of a crank mechanism with elastic elements; a diagram of the forces acting on the crank mechanism, the derivation of the torque formula; in FIG. 46 - crank pin in neutral position; in FIG. 5 is a kinematic diagram of an additional crank mechanism.

The stand consists of a frame 1, at the ends of which there are fixed adjustable screw supports 2 with nuts 3, to which one of the ends of the tested elastic elements 4 is mounted, a drive in the form of an electric motor 5 with a pulley b, which is connected via a belt 7 to a pulley 8, seated rigidly on the shaft 9, which is rigidly connected to the gear 10. The shaft 9 is mounted in brackets 11 located on the frame 1. In the middle of frame 1, a shaft of the crank mechanism 12 is mounted on bearings 13, at one end of which, outside the frame 1, a gear wheel 14 is fixedly engaged with the gear 10. A bearing 16 is inserted onto the pin 15 of the shaft of the crank mechanism 12, which enters into a rectangular the groove 17 of the slider 18 with the eyes 19 for attaching the movable ends of the corresponding elastic elements 4. The guide for the slider 18 is the beam of the frame 1. The rectangular groove 17 is its largest vertical oriented and therefore the vertical beats of the finger 15 are not are transmitted to the slider, while the horizontal size of the groove is made with a small (thermal) clearance relative to the outer size of the bearing 16 and because the slider 18 tracks the horizontal beats of the finger 15, passing them to the elastic test elements 4.

On the outside of the frame 1 on the axis 20

a gear wheel 21 is installed, which is meshed with the wheel 14. A rigid crank 22 is fixed to the wheel 21, which enters the rectangular groove 23 of the slider 24 which is placed in the guides 25 and

connected to a power spring 26, the other end of which is fixedly mounted on the frame 1. A bearing 27 is mounted on the crank 22 to reduce friction when moving along the groove 23. The groove 23 is longer

oriented perpendicular to the direction of movement of the slider 24, which allows the additional crank to move freely perpendicular to the guides 25, and the small size is made according to

the size of the outer ring of the bearing 27 with a thermal clearance, and therefore the displacement of the crank mechanism along the guides causes equal movement of the slider 24 with a fixed power spring

26. The counter of cycles 28 is fixed on the top of the frame 1.

The stand works as follows.

In the eyes 19, the test elastic members 4 are fixed with their movable ends. The release of the nut 3, to the fixed supports 2, the other ends of the corresponding elastic elements 4 are fastened. Turning on the drive motor 5, turn the wheel 14 in such a way that the pin of the crank mechanism becomes neutral, i.e. it will not create tension in any of the elastic elements arranged horizontally (see Fig. 46). In this case, the power

the spring 26 is maximally stretched by the crank 22. The gaps 3 select gaps in the joints of the elastic elements 4 with the eyes 19 and the supports 2, and if necessary (according to the technical requirements for the elastic elements 4), either tension or compression is created. To fix the wheel 14 in this installation (neutral) position, latches can be provided, and to identify it, risks or marks on the wheel 14 and on the frame 1.

Since the force spring 26 was extended and energy was stored in it, when the drive (engine 5) is turned on, the finger 15, turning, will begin to compress one of the elastic elements 4, and the other will stretch, which will consume the energy stored in the power spring 26. When the wheel 14 is rotated 90a, one of the elastic elements 4 will be compressed as much as possible and the other stretched, the wheel 21 will turn 1804 i.e. spring 26 completely gives up energy, the torque becomes zero, because in this position, the shoulder of the action of forces from other elements will be zero I cos) - see Fig. 4a. Upon further rotation through 90 °, the elastic elements 4 will return the stored energy, i.e. the torque will be negative, This energy will be absorbed by the power spring 26. Next, the process will be repeated at other quarters of rotation of the wheel 14. In this case, the wheel 21 will be rotated 180 °, because its diameter is 2 times less than the diameter of the gear 14 (Fig, 5). We find the average force of the power spring 26 from the condition of equality of the moments created on the shaft of the crank mechanism 12 (see Fig. 4a) with sin 2, i.e. at the maximum moment and moment on the wheel 21 created by the power spring 26 acting by means of the slider 24 on the crank 22 located at a radius rk (see Fig. 5)

Xie

For satisfactory balancing, it is desirable that the forces of the spring 26 at the extreme points of the position of the crank 22 differ by no more than 10%. Thus, we get that, 05RSp, 95 PCp. The stroke (spring deformation) will be. From here we find recommendations for choosing the stiffness of the power spring 26-S.s.p .:

0,1Р

-

wed

2gk

(kgf / mm)

P 1P2P2

that 0-025 f

()

From the use of the inventive test bench for testing elastic elements for fatigue in comparison with the prototype A. USSR M 1401328. taken as a base for comparison, the following positive effect is expected:

a) technical advantages - full balancing of torque is ensured by an additional mechanism that implements the mechanically trigonometric function of the sine of the double angle;

b) socially useful advantages derived from technical ones - the return of deformation energy is ensured.

of the tested elements, the energy expenditures are reduced ten times, the durability of the stand is increased several times.

Claims (1)

SUMMARY OF THE INVENTION A fatigue testing stand for elastic elements, comprising a frame with a guide, two supports for securing one of the ends of the respective elastic elements, a sliding slider in the guide with movable supports for securing the second ends of the respective elastic elements, and a slider drive including a crank a mechanism whose finger is connected to a slider, characterized in that, for the purpose of reducing the energy consumption of the drive used, the supports are mounted coaxially with the guide symmetrically with respect to the slide, and the stand is equipped with two gears that are in meshing, the first of which is mounted on the axis of the crank, and the second is mounted on the frame, with an additional crank mounted on the second wheel and a power spring, one end of which is connected to the frame, the other to an additional crank, and the diameter of the first gear is twice the diameter of the second gear. Fig.Z a c esinoc