RU2516920C2 - Vibration absorber of large carrying capacity with tapered bushes - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: vibration absorber comprises two tapered resilient bushes from wire non-woven web of rubber-metal material. Small concentric collars are made on the casing, cap and flange of a central bush and are used to align the tapered bushes and provide for radial preloading. Axial preloading in the tapered bushes is created by tightening the lower slotted nut up to the stop of the cap against the coupler screw collar and of the face of the central bush against the cap. The vibration absorber casing is fitted by a flange by which the vibration absorber is connected to a base plate. A unit with its vibration to be absorbed is mounted on the cap and fixed by a washer, the second slotted nut and a split pin. When free, the outer diameter of the tapered bushes is equal to the inner diameter of pilot collars of the casing, cap and flange of the central bush. Diameter of the centre opening of the tapered bushes is equal to the outer diameter of the inner pilot collars of the cap and flange of the central bush. When free, the cone angle of the tapered bushes is determined according to the formula. The height of pilot collars is chosen so that alignment of bushes as per the collars is provided immediately before the creation of preloads on contact surfaces of tapered bushes when they are free.

EFFECT: simplification of assembly procedure for a vibration absorber without its performance characteristics being deteriorated.

3 dwg

Description

The invention relates to vibration-isolating all-metal devices of medium and heavy lifting capacity, capable of operating in an aggressive environment, in vacuum, in radiation conditions and at elevated temperature (up to 450 ° C).

The abbreviation VVK stands for vibration isolator with tapered bushings.

There is a known high-capacity vibration isolator (see Kotov A. S. Calculation of the elastic-damping characteristics of vibration isolators from MR material // Abstract of dissertation for the degree of candidate of technical sciences. - Samara - 2007), containing a housing, two conical elastic bushings from wire nonwoven material MR ( “Metal rubber”), cover, central sleeve, collar screw with shoulder and fasteners - washers, slotted nuts and cotter pins. Small concentric flanges are made on the body, cover and central sleeve, along which the tapered bushings from MR are centered and a radial interference is created in them. The axial interference in the bushings from MP is created by tightening the lower slotted nut (if the axis of the vibration isolator is vertical) until the cover stops against the collar of the coupling screw and the end of the central sleeve into the cover, and in this position the nut is split. The vibration isolator case has a flange, with which the vibration isolator is attached to the base. The vibration-isolating object is placed on the cover and secured with a washer, a second slotted nut and a cotter pin.

The vibration isolator can be used for spatial loading. Its elastic sleeves operate in a two-sided elastic hysteresis stop under loading in all six degrees of freedom. Among its positive qualities should be attributed to its relatively small dimensions and weight, simplicity of design.

By technical nature, this vibration isolator is closest to the proposed and adopted as a prototype.

When assembling a vibration isolator to create a radial interference between the tapered bushings from MP and the cylindrical flanges of the vibration isolator parts, these parts are pressed onto the bushings, which requires special equipment and the technology of assembling the vibration isolator is significantly complicated.

Therefore, the task is to simplify the assembly technology of the VVK vibration isolator without reducing its technical characteristics.

The problem is solved by the fact that the VVK vibration isolator of large carrying capacity is proposed, comprising a housing, two conical elastic bushings made of MP wire non-woven material, a cover, a central sleeve, a clamping screw with a shoulder and fasteners - washers, slotted nuts and cotter pins, and on the case, cover small concentric flanges are made and the flange of the central sleeve along which the tapered bushings from MR are centered and a radial interference is created in them, and the axial interference in the bushings from MR is created by tightening the lower slotted nut d about the stop cover in the collar of the coupling screw and the end face of the central sleeve in the cover, and the vibration isolator body has a flange that secures the vibration isolator to the base, and the vibration-insulated object is placed on the cover and secured with a washer, a second slotted nut and cotter pin, characterized in that the conical bushings from MR their outer diameter is equal to the inner diameter of the centering flanges of the housing, cover and flange of the central sleeve, and the diameter of their central hole is equal to the outer diameter of the inner centering flanges of cr arms and the flange of the Central sleeve, and the cone angle of the conical bushings from MP in this state is determined in radians from the ratio

$$\varphi =2arctg\frac{(D_n-D_{\mathrm{about}t\mathrm{at}})tg\frac{{\varphi }_{\mathrm{one}}}{2}}{D_n-D_{\mathrm{about}t\mathrm{at}}+2Atg\frac{{\varphi }_{\mathrm{one}}}{2}},$$

where D _n - the outer diameter of the conical bushings of MR, D _holes - the diameter of the central opening of conical bushings, φ ₁ - cone angle surfaces of the housing, lid and flange of the central sleeve, which rely conical sleeve of MR A - maximum value conical clearance between mating conical surfaces - bushings and parts on which it rests in the free state of the bushings, specified from the condition of preventing destructive processes at the bushings in places of their contact with the centering beads of the housing, cover and flange of the central the size A, it is recommended to take A equal to 5 ... 6% of the thickness of the sleeve H, measured in the vertical direction, and the height of the centering beads is chosen so that immediately before creating interference on the contact surfaces of the conical bushings from MP, in their free state, centering the bushings along collars.

When assembling the proposed vibration isolator, the conical bushings are installed in the places intended for them, and the parts are installed manually on the bushings without the use of special equipment, and the required axial and radial tightnesses on the contact surfaces of the elastic hysteresis elements (UGE) of the vibration isolator - elastic conical bushings from MR are created by tightening the lower slotted nut to the cover stop in the shoulder of the coupling screw and the end of the central sleeve in the cover.

This greatly simplifies the assembly of the proposed vibration isolator.

The proposed design of the vibration isolator is illustrated by drawings. In the drawings, the vibration insulated object, the base to which the vibration isolator is attached, and the fasteners with which the vibration isolator is attached to the base, are depicted by a thin solid line as the “situation” in the assembly drawing.

Figure 1 shows a longitudinal section of the proposed vibration isolator VVK.

Figure 2 shows a top view of this vibration isolator.

Figure 3 shows a longitudinal section of a vibration isolator with elastic bushings from MP in a free state, before creating a radial and axial interference in them.

The proposed VVK vibration isolator of large capacity (see Figs. 1 and 2) contains a housing 1, two conical elastic bushings 2 made of MP wire nonwoven material (UGE vibration isolators), a cover 3, a central sleeve 4, a tightening screw 5 with a shoulder 6 and fasteners washers 7, slotted nuts 8 and cotter pins 9. Small concentric flanges 11 are made on housing 1, cover 3 and flange 10 of central hub 4, along which tapered sleeves from MP 2 are centered. The tightening screw 2 is centered in flange 6 in cover 3, which centered in turn sleeve 4. On the contact surfaces of the tapered bushings 2, a radial and axial interference was created by tightening the lower slotted nut 8 until the cover 3 abuts against the shoulder 6 of the coupling screw 5 and the end face 12 of the central sleeve 4 into the cover 3. The housing 1 of the vibration isolator has a flange 13 that secures the vibration isolator to the base 14 with screws 15, washers 16, elastic washers 17. The vibration-insulated object 18 is placed on the cover 3 and secured with a washer 7, a second slotted nut 8 and a cotter pin 9.

In the free state of the tapered bushings 2 of MR (see FIG. 3), their outer diameter is equal to the inner diameter of the centering collars 11 of the housing 1 and the covers 3, and the diameter of their central hole is equal to the outer diameter of the inner centering collars 11 of the covers 3. The cone angle of the tapered bushings 2 from MR in this state is determined in radians from the relation

$$\varphi =2arctg\frac{(D_n-D_{\mathrm{about}t\mathrm{at}})tg\frac{{\varphi }_{\mathrm{one}}}{2}}{D_n-D_{\mathrm{about}t\mathrm{at}}+2Atg\frac{{\varphi }_{\mathrm{one}}}{2}},$$

where D _n is the outer diameter of the tapered bushings 2 of MP, _Dot is the diameter of the central hole of the tapered bushings 2, φ ₁ is the cone angle of the surfaces of the housing 1, cover 3 and flange 10 of the central bush 4, on which tapered bushings 2 of MP, A are supported - the largest value of the conical gap between the mating conical surfaces of the sleeve and the part on which it rests in the free state of the sleeve, specified from the condition of preventing destructive processes at the bushings in places of their contact with the centering collars 11. The value of A is recommended for be equal to 5 ... 6% of the thickness of the sleeve N, measured in the vertical direction. The height of the centering flanges 11 is chosen such that immediately before creating interference on the contact surfaces of the conical bushings 2 of the MP, in their free state, they are centered on the flanges. Fulfillment of this condition excludes the possibility of crushing the edges of the bushings when creating interference in them.

The recommended value of A is determined by calculation using the results of experimental studies of the prototype with various radial tightnesses on bushings from MR, as a result of which the values of radial tightness at which the mutual slippage of the turns of wire material of the bushings along the side disappears for the interval of densities of material MR used in heavy-duty vibration isolators contact surfaces of the centering collars of the parts, which leads to a decrease in the elastic-friction characteristics of the vibration isolator s and the appearance of fatigue breaks in the material of the shoulder.

The choice of the value of A within the specified limits avoids these negative processes and, therefore, increases the service life of the proposed vibration isolators.

The assembly of the proposed VVK vibration isolator is simple and not described in detail.

When assembling the proposed vibration isolator, the conical bushings 2 are installed in the places intended for them, and the parts are installed manually on the bushings 2 without the use of special equipment, and the required axial and radial tightnesses on the contact surfaces of the elastic hysteresis elements (UGE) of the vibration isolator - elastic conical bushings 2 from MP are created simultaneously by tightening the lower slotted nut 8 until the stop of the cover 3 in the shoulder 6 of the coupling screw 5 and the end 12 of the central sleeve 4 in the cover 3. In this position, the nut 8 is checked with a cotter pin 9.

As already mentioned, the advantage of the proposed VVK vibration isolator with a large lifting capacity compared to the prototype is the significantly simpler and cheaper technology for their assembly, which does not require the manufacture of special equipment for installing the conical bushings 2 in their intended places and parts of the vibration isolator on these bushings with the required radial tight fit.

Claims (1)

A heavy-duty vibration isolator with tapered bushings, comprising a housing, two tapered elastic bushings of wire non-woven metal-rubber material, a cover, a central hub, a clamping screw with a shoulder and fasteners — washers, slotted nuts and cotter pins, and are made on the housing, cover and flange of the central hub small concentric flanges along which the conical bushings of metal rubber are centered and a radial interference is created in them, and the axial interference in the bushes of metal rubber is created by tightening the lower slotted nut ki until the stop of the cover in the collar of the coupling screw and the end of the central sleeve into the cover, and the vibration isolator case has a flange that secures the vibration isolator to the base, and the vibration-insulated object is placed on the cover and secured with a washer, a second slotted nut and cotter pin, characterized in that in the free state conical bushings made of metal rubber, their outer diameter is equal to the inner diameter of the centering flanges of the housing, cover and flange of the central sleeve, and the diameter of their central hole is equal to the outer diameter of the inner center boiling the beads cover and a central hub flange, and the cone angle of the conical bushing-metal in this condition is determined from the ratio in radians
$$\varphi =2arctg\frac{(D_n-D_{\mathrm{about}t\mathrm{at}})tg\frac{{\varphi }_{\mathrm{one}}}{2}}{D_n-D_{\mathrm{about}t\mathrm{at}}+2Atg\frac{{\varphi }_{\mathrm{one}}}{2}}$$

,
where D _n is the outer diameter of the conical bushings made of metal rubber, D _resp is the diameter of the central hole of the conical bushings, φ ₁ is the cone angle of the surfaces of the housing, the cover, and the flange of the central bush on which the conical bushes made of metal rubber rest, A is the largest conical gap between the reciprocal conical surfaces - bushings and parts on which it rests in the free state of the bush, specified from the condition of preventing destructive processes at the bushings in places of their contact with the centering shoulders of the housing and roofs k, the value of A is recommended to be taken equal to 5 ... 6% of the thickness of the sleeve H, measured in the vertical direction, and the height of the centering beads is chosen so that immediately before creating interference on the contact surfaces of the conical bushings from metal rubber, in their free state, centering the bushings along collars.

Images