RU2348840C1 - Vibration absorbing support and its fabrication method - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention deals with devices used for reduction of vibrations and impacts generated in the course of machinery operation and for anti-vibration protection of highly sensitive equipment. The support is composed of at least two vibration isolators represented by spirals fabricated of steel cord with support plates. The plates, attached to the spiral coils, are positioned within diametrically opposite planes. The support plates are mounted onto the support structure sections having bounding surfaces and positioned at an angle of α relative to the horizontal plane. The longitudinal axes of the vibration isolator spirals are parallel to each other. There is a clearance arranged between the spiral coils exterior surface and the bounding surfaces of the vibration-absorbing support structures. The clearance width is equal to 0.2-0.8 of the allowable vibration isolator deformation. The proposed fabrication method is as follows: while the vibration isolators mounted onto one of the support structures remain in the free state the support plates of those mounted onto another support structure are shifted relative to each other by a distance of l=xSinα where x is the absorber allowable static deformation value.

EFFECT: enhanced reliability of the vibration-isolating support combined with useful life extension and fabrication process simplification.

2 cl, 4 dwg

Description

The invention is used in mechanical engineering and relates to devices used to reduce vibration and shock from operating equipment, such as heavy rotary and reciprocating machines, marine engines, diesel generators, hammers, etc., and also to protect sensitive equipment, electronics and various vibration-sensitive devices and protection against shock loads during transportation, firing and in emergency cases, in particular in earthquake-prone areas.

Known vibration damping supports containing vibration damping elements, for example, in the form of a spiral of a steel cable and two pairs of plates fastened together by a threaded connection at diametrically opposite points of the circumference of the spiral (see Cavoflex Shock and Vibration Mounts with outstanding features, Schiff and Hafen No. 10. 1988 - vibration-damping support CAVOFLEX by Willbrandt Gummitechnic).

However, the vibration-isolating elements of this known vibration-damping device have a large free movement without insurance means from compressive and tensile deformations when the load values are more than permissible. Therefore, for such loads, additional means should be provided to limit compression deformation, tension and shear of the elastic element of the vibration isolator.

The known vibration-damping support according to the patent EP 0059143 (priority of France dated February 17, 1981), adopted as a prototype, also contains vibration-isolating elements from a steel cable spiral with support plates mounted on spiral turns in diametrically opposite planes and mounted on supporting structures of vibration-damping support, which have surfaces that limit the deformation of the coils of the spiral.

However, this design also has the disadvantage that there is no gap between the bounding surfaces and the spiral coils of the vibration isolating element, which reduces the stroke of the shock absorber and increases the degree of nonlinearity of the stiffness parameters. In addition, to prevent collision of the supporting structures, additional elastic elements are installed. At the same time, the manufacturability of the vibration damping device as a whole is reduced and its working stroke is reduced.

Known methods for the manufacture of vibration damping supports.

Thus, in the manufacture of the CAVOFLEX vibro-damping support by Willbrandt Gummitechnic, spiral coils are formed by winding the cable onto the matrix with an interference fit, which reduces the cable diameter in the coils due to its tension. Then follows fixing the coils between the two plates with screws. The disadvantage of this method is the need for complex additional equipment for stretching the cable, machining the halves of the plates, drilling and threading in the holes for compressing the halves of the plates when fixing the cable between them.

In the manufacture of the known vibration-damping support according to the patent EP 0059143, additional nodes of various shapes are used to provide bounding surfaces, which require complex machining and mounting accuracy for a uniform fit of the spiral coils. In addition, the limiting surface does not protect against hard impact when choosing a free run, and there is no alignment of stiffness characteristics on different axes.

The objective of the invention is to increase the reliability of the vibration isolating support, increase the service life and simplify the technology of its manufacture.

As in the prototype, this problem is solved in that the vibration damping support contains at least two vibration isolators made in the form of a spiral of a steel cable with support plates mounted on spiral coils in diametrically opposite planes and mounted on supporting structures of a vibration damping support equipped with bounding surfaces.

The difference is that the support plates are fixed on the sections of the supporting structures made at an angle α to the horizontal. In this case, the longitudinal axes of the spirals of the vibration isolator are parallel to each other, and a gap is made between the outer surface of the spiral coils and restrictive surfaces on the supporting structures of the vibration damping support, the value of which is selected in the range of 0.2-0.8 of the permissible deformation of the vibration isolator.

This problem is also solved by the fact that, as in the prototype, in the manufacture of the vibration damping support, the vibration isolators are supported by the support plates on the supporting structures of the vibration damping support.

The difference is that on one supporting structure the vibration isolators are installed in a free state, and on the other supporting structure the vibration isolators are mounted when their bearing plates are forced to displace to each other or from each other by a distance l = xSinα, where x is the permissible static deformation of the shock absorber.

The invention is illustrated by drawings:

Figure 1 - General view of the vibration damping support;

Figure 2 - options bounding surfaces of the vibration damping support;

Figure 3 - action diagram of the bounding surfaces.

The vibration damping support consists of supporting structures 1 and 2, which have sections 3 and 4, made at an angle α to the horizontal. On these inclined sections of the supporting structures, vibration isolators are installed from the spirals of the steel cable 5 with the supporting plates 6 and 7, while the longitudinal axis of the spirals of the vibration isolator are parallel to each other. The supporting structures 1 and 2 have bounding surfaces 8, forming a gap with the outer surface of the spiral turns of the vibration isolators, the value of which A is 0.2-0.8 of the permissible deformation of the vibration isolator. This value is set in accordance with the requirements to limit the maximum allowable deformation and reduce the shock load on the vibration-insulated object in case of loss of elasticity of the vibration isolator spiral in the event of a strong impact, explosion or other dynamic effect, causing the vibration isolator to deform above its maximum stroke.

The deformation is limited above the permissible level by increasing the stiffness of the vibration isolator when touching the spiral coils of the limiting surfaces 8. The impact load is reduced first by increasing the rigidity of the vibration isolator, and then, when the elasticity of the vibration isolator is lost, due to the cable being crushed when the supporting structures of the vibration damping support come in contact with it . As shown in figure 2, the bounding surface of the vibration-isolating supports, depending on the requirements for limiting the maximum displacements, can be made in various ways, for example, in the form of protrusions 9, 10, 11 and depressions 12.

The device operates as follows.

If the maximum permissible deformation is exceeded, for example, with vertical overload, as shown in Fig. 3, since the stiffness of the vibration isolator depends on the length of the free length of the spiral cable and the diameter of the half ring formed by it, then when the local contact B between the turns 5 and the bounding surfaces 8 appears, the conditional length and the diameter of the half ring 5, which is equivalent to the appearance of elastic elements of increased rigidity. Due to the fact that the coils touch not at the same time, and also in the first moments of touch the cable slides along the bounding surfaces, the increase in stiffness occurs gradually. In case of loss of elasticity, in the case of significant shock overloads, the supporting structures 1 and 2 will rely on increasingly shortened coils of the cable, eventually losing their elasticity, gradually increasing their rigidity up to plastic deformation of the cable and absorbing shock energy more and more.

A method of manufacturing a vibration damping support is that the vibration isolators fix one of the support plates on an inclined section of one of the support structures of the vibration damping support in a free state, then force the other support plate of the vibration isolator to each other or from each other by a distance I = xSinα and fasten it on an inclined section of another supporting structure.

The supporting structures for installing the vibration isolator spirals ensure their reliable fixation from a possible turn during operation and are performed in such a way that the milling depth ensures that the cable does not contact the bounding surfaces of the supporting structures of the vibration-damping support in the range of permissible loads. The angle α of the inclination of the sections of the supporting structures is selected from conditions that provide the necessary amount of forced displacement of the base plates of the vibration isolators relative to each other.

The proposed vibration damping support and the method of its manufacture ensure the achievement of new design properties:

- when the stroke of the shock absorber is exceeded, there is no hard collision of the shock absorber support structures, while a smooth increase in stiffness is ensured when the support structures come closer together of the vibration-insulated object;

- it is possible to ensure the optimal ratio of the vertical stiffness of the shock absorber to shear stiffness in any direction;

- decreases the ratio between the height of the shock absorber and the allowable amount of vertical deformation.

Thus, the listed new properties of the claimed design provide an increase in the reliability of the vibration isolating support, an increase in the service life and simplification of the technology for its manufacture.

Claims (2)

1. Vibration-damping support, containing at least two vibration isolators made in the form of a spiral of a steel cable with support plates mounted on the turns of the spiral in diametrically opposite planes and mounted on supporting structures of a vibration-damping support provided with restrictive surfaces, characterized in that the support plates are fixed on sections of the supporting structures made inclined at an angle α to the horizontal, while the longitudinal axis of the spirals of the vibration isolator are parallel to each other, and between eshney surface of spiral turns, and the stopping surfaces formed on the supporting structures backlash vibration damping support, the magnitude of which is chosen in the range from 0.2-0.8 permissible strain isolator. 2. A method of manufacturing a vibration damping support according to claim 1, wherein the vibration isolators are mounted on the supporting structures on the supporting structures of the vibration damping, characterized in that the vibration dampers are installed on one supporting structure in the free state, and the vibration dampers are attached to the other supporting structure upon forced displacement their support plates to each other or from each other at a distance l = xSinα, where x is the permissible static deformation of the shock absorber.

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