RU2460911C2 - Ribbon-shoe brake - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: proposed brake comprises brake pulley and rake ribbon with friction linings arranged on leading and training flights at variable pitch, drive of said linings and brake mechanical drive. Friction linings are jointed together by different-rigidity cable passed through ribbon holes. Said cables allows independent displacement of friction linings on ribbon runs. Brake band runs are provided with recesses to receive bushes with solid bulges on their ends for cables to run there over and pressed from above by lugs. Leading run cable makes a closed circuit. Leading edge cable lengths are fitted inside fixed bushes arranged at start and end of leading band. Band trailing end cable represents incomplete circuit with independent ends.

EFFECT: higher efficiency of braking.

2 cl, 10 dwg

Description

The invention relates to mechanical engineering and can be used in tape-shoe brakes of drill hoists.

A tape brake is known with movable friction linings, which contains separate stationary linings at the beginning of the oncoming branch of the brake belt, in the middle of the belt and at the end of the runaway branch of the belt, and between the fixed linings there are movable linings, which have cuts in their upper part along their width mounted in the L-shaped grooves of the tape, while the movable pads have the ability to move relative to the inner surface of the tape and the working surface of the pulley, and on the incoming and outgoing branches x tape there is an unequal number of movable pads, interconnected by springs of different stiffness [1, analog]. The disadvantage is that a clear redistribution of specific loads between two metal friction elements, i.e. with a belt and a pulley when the brake is working.

A tape brake is known with sectional friction linings on the brake belt, in which coincident radial holes are made along its edges and friction linings, which in the body of the linings go into mutually perpendicular holes one third of their width and are located at the height of the allowable wear of the working surfaces lining, and at the same time through the system of holes ropes are passed, envelope blocks mounted on the outer surface of the brake tape, and on the side of the oncoming portion of the tape the ends of the channel instituted in that it a lock plate, from the same area of the belt escapes the rope goes around a side surface of the last section of the friction lining. At the same time, in friction pairs “overlay-pulley” and “overlay-tape”, dynamic equalization of specific loads is achieved due to the movement of the overlays in sections with the help of pulley systems having different rope stiffness on the branches of the brake belt [2, prototype]. The proposed technical solution allows you to adjust the specific load only on the sections of the brake band between the lining section.

Compared with the analogue and prototype, the proposed technical solution has the following distinctive features:

- the simultaneous use of two pairs of friction "pad-pulley" and "pad-tape", while the working surfaces of the metal friction elements have the same roughness;

- the use of ropes with different stiffness on the branches of the brake tape, not only as fasteners for the linings, but also as sections for their movement;

- the possibility of not only static alignment of specific loads along the branches of the brake band, but also their dynamic redistribution between the linings on the branches of the brake band;

- the ability to control along the perimeter of the brake tape the tension of the closed and open contours of the ropes using a special device as the wear surfaces of the friction lining;

- the role of the elastic elements by the contours of the ropes, providing a reduction in the low-frequency vibrations of the friction linings located on the branches of the brake band.

The objective of the invention is to increase the efficiency of friction brake assemblies due to the static-dynamic redistribution of specific loads in their friction pairs on the incoming and outgoing branches of the brake band.

This goal is achieved by the fact that on the branches of the brake tape along the length of the lining displacement grooves are made, in which there are bushings pressed against the antennae and having continuous thickenings at their ends, made in the form of blocks enveloped by sections of ropes, and the entire rope of the oncoming branch is made in the form of a closed loop, and its sections are brought into the volumes of stationary bushings located at the beginning and at the end of the oncoming branch of the tape, and in the volume of the last of them, sections of the ropes of the oncoming and running branches are connected between by itself, and at the same time on the runaway branch of the tape, the rope is made in the form of an open loop with independent ends. Moreover, in the friction pairs of the brake “lining-pulley” and “lining-tape”, the tension of the rope circuits is achieved due to the fact that the independent ends of the ropes are connected through the rollers with fixed axles to the fixed pins of the rotatable cam made in one with the handle for controlling the tension of the rope circuits providing the movement of the friction linings on the branches of the brake belt relative to the working surface of the brake pulley for dynamic alignment of specific loads in the external and internal pairs of friction of the brake.

Figure 1 shows a General view of the tape-shoe brake; figure 2, 3, 4 illustrates the steps of the layout of the linings on the arc of grasping the brake band; figure 5 shows the brake belt with the layout of the friction linings on the incoming and outgoing branches with the main and additional sprung braces; figure 6 is a transverse section aa of the friction unit in figure 1; Fig.7 is a transverse section bB of the movable sleeve in Fig.5 (without plot of the brake tape); in Fig.8 is a transverse section bb of the stationary sleeve of Fig.5 (without plot of the brake tape); figure 9 is a view G of the node "rope-sleeve-tape" in figure 5; figure 10 - rope tensioning device.

Legend: ω is the angular speed of the brake pulley S _H , S _C is the tension of the oncoming (I) and runaway (II) branches of the brake belt; P is the force on the control handle of the tensioner of the rope circuits.

The tape-shoe brake contains a pulley 1 with flanges 2, mounted on the shaft 3 of the mechanism. The brake band 4 is fastened with its running branch (I) to the support 5, and the running branch (II) - to the brake control lever 6. On the brake tape 4 are movable friction linings 7 with the working 8 and non-working 9 surfaces that are installed on its branches with different constant steps as follows.

равно отношению удельных нагрузок, возникающих на набегающей (I) (р_Н) и сбегающей (II) (р_С) ветвях тормозной ленты. Таким образом, по величине отношения

можно определить, на сколько больше фрикционных накладок необходимо установить на набегающей ветви (I) ленты 4, чем на сбегающей (II).When calculating the rational number of friction linings 7 installed with different constant clearance on the incoming (I) and escaping (II) branches of the brake belt, the coefficient of mutual overlap of the contacting surfaces for each of its branches is determined. Since the mutual overlap coefficient is proportional to the product of the areas of the contacting friction surfaces, the ratio

equal to the ratio of the specific loads arising on the running (I) (p _N ) and running (II) (p _C ) branches of the brake band. Therefore, the largest ratio

you can determine how much more friction linings you need to install on the oncoming branch (I) of the tape 4 than on the runaway (II).

The first stage consists in the placement of the friction linings along the working length of the brake band, which allows you to uniquely outline the border of its oncoming and descending branches. According to figure 2 at the ends of the brake tape 4 we install the friction lining (a) and (c), as well as one lining (b) in its middle part, half of which belong to the end of the oncoming (I) and the beginning of the runaway (II) branches of the tape 4 The installation of the friction lining (b) in the middle part of the belt 4 is connected with the fact that when the brake closes, the working surface of this particular lining will first begin to interact with the working surface of the brake pulley 1.

между торцами накладок (а) и (в). Для этого используют зависимость вида

, где l - расстояние по дуге ленты 4 между торцами накладок (а) и (в); D - диаметр тормозной ленты [D=d_Ш+2h_H); d_Ш - диаметр тормозного шкива; h_H - толщина фрикционной накладки 7. В дальнейшем пользуются значением произведения ширины фрикционной накладки 7 на количество накладок (n), которые будут размещены на угле α_1. После чего от общей длины l набегающей ветви (I) ленты 4 отнимают длину, которую занимает намеченное количество накладок (n). Для распределения длины, которая осталась для постоянных зазоров между фрикционными накладками (α) для набегающей ветви ленты, используем зависимость вида

, где l_H - длина набегающей ветви ленты; b_H - ширина фрикционной накладки (α). На этом второй этап заканчивается.The second stage consists in determining the value of the constant step between the ends of the friction linings (a) and (b) on the incident branch (I) of the brake tape 4. First, according to Fig. 3, the central angle is determined

between the ends of the pads (a) and (b). For this, a dependence of the form

where l is the distance along the arc of the tape 4 between the ends of the plates (a) and (b); D is the diameter of the brake tape [D = d _W + 2h _H ); d _Ш - diameter of the brake pulley; h _H is the thickness of the friction lining 7. The value of the product of the width of the friction lining 7 and the number of lining (n) that will be placed at an angle α _{1 is} then used _. Then, the length that takes up from the total length l of the oncoming branch (I) of the tape 4 Target number of pads (n). To distribute the length that remains for constant gaps between the friction linings (α) for the incident branch of the tape, we use a dependence of the form

where l _H is the length of the incident branch of the tape; b _H is the width of the friction lining (α). At this second stage ends.

где l_C - длина сбегающей ветви ленты с (m) накладками на ней.The third stage is to determine the value of the constant step between the ends of the friction linings (c) and (b) on the runaway branch (II) of the brake belt, which is determined from the formula

where l _C is the length of the runaway branch of the tape with (m) overlays on it.

The third stage is no different from the second stage. The dependence (1) is used, in which α ₁ = α ₂ , as well as expression (3), in which it is necessary to substitute the designation m instead of n (the number of overlays on the runaway branch (II) of the brake belt 4 (Fig. 4). This is the third stage ends.

Figure 5 illustrates an example of the layout of the linings on the arc of the grasp of the brake belt and its main and additional sprung guy. In this case, the constant gap between the friction linings (b) of the runaway branch (II) of the brake tape 4 is much larger than the constant gap between the linings (b) of its ramp (I).

для ее быстрого отвода от тормозного шкива 1, а также обеспечивая поддержание постоянного зазора между парами трения тормоза, наряду с основными подрессорными оттяжками 10 применяют дополнительную 11.Due to the fact that the weight load on the runaway branch (I) of the brake tape 4 increased by the value of the ratio

for its quick removal from the brake pulley 1, as well as ensuring that a constant gap between the friction pairs of the brake is maintained, an additional 11 is used along with the main springs 10.

Thus, for targeted static redistribution of specific loads between the running and running branches of the brake belt, taking into account its operational ability, it is necessary to correctly determine by calculation the number of friction linings falling on the running and running branches of the brake belt, and to establish the values of the constant gaps between the plates.

Moreover, under the non-working surface 9 of each lining 7 there are reinforcing rods 12 and a plate 13 extending beneath them and covering them with their side walls. Below, flush with the side wall of the plate 13 and under it are two longitudinal holes 14 in each friction lining 7. Similar holes 15 are made on the surface of the brake band 4 near its depressions 16, which are some kind of restriction of the movement of the friction linings 7 along the working surface of the brake band 4. In addition, the presence of a smaller number of depressions 16 on the runaway branch (II) of the tape 4 makes this area pliable. The axis of the centers of the holes 14 and 15 are made in the form of right and left rows, coincide in two planes.

In the hollows 16 of the brake tape 4, fixed sleeves 17 are installed at the beginning and end of its oncoming branch (I), and on all other sections of the tape 4 there are movable sleeves 18 having thickened ends of the groove 19. The sleeves 17 and 18 are fastened with the help of the antennae 20, being one with the body of the brake tape 4.

The closed loop of the rope 22 of the running branch (I) of the brake tape 4 includes the grooves 19 of the movable sleeves 18 and the holes 14 of the friction linings 7, as well as the volumes 21 of the stationary sleeves 17, in which there are sections of the rope 22. Throughout the volume 21 of the stationary sleeve 17 located on the boundary between the branches (I and II) of the brake tape 4, the closed loop section of the cable 22 is connected to the open loop section of the cable 23. The latter extends under the runaway branch (II) of the brake tape 4, and this includes, in addition to the above sections for closed loop e e and sections of the ropes 23 between the movable sleeves 18 and the ends of the friction linings 7. The two ends 24 and 25 of the open circuit of the rope 23 of the runaway branch (II) of the brake band 4 are encircled by the rollers 26 located on the fixed axles 27 and then attached to the pins 28 of the cam 29 , which is connected with the control handle 30 of the device for regulating the tension of the closed 22 and open 23 circuits of the ropes (I and II) of the brake tape 4. The device is located on the panel 31.

In the process of operation of the tape-shoe brake, the inner surface of the brake tape 4 and the idle surfaces 9 of the friction linings 7 form the external friction pairs, and the working surfaces 8 of the linings 7 with the working surface of the pulley 1 - the internal friction pairs.

, основным слагаемым которой является динамический коэффициент трения скольжения (f_C). Кроме того, между внутренней поверхностью тормозной ленты 4 и нерабочей поверхностью 9 накладки 7 возникает сила трения покоя F_П. При этом необходимо учитывать тот факт, что чистота внутренней поверхности тормозной ленты 4 отвечает чистоте поверхности тормозного шкива 1, а рабочая 8 и нерабочая 9 поверхности накладок 7 перед их установкой на ленту 4 обработаны и имеют одинаковую шероховатость. В какой-то момент времени торможения с увеличением прикладываемого усилия к рычагу управления 6 суммарные силы

и F_П в накладках 7 преодолеют силы сопротивления, действующие на участках замкнутого 22 и незамкнутого 23 контуров канатов в системе отверстий 14 накладок 7 и отверстий 15 в ленте 4, в желобах 19 втулок 18 и взаимодействия их наружных поверхностей с поверхностями впадин 16 и усиков 20 на тормозной ленте 4, что и вызывает вращение втулок 18 и, как следствие, перемещение фрикционных накладок 7 на ветвях I и II тормозной ленты 4. Последнее будет способствовать динамическому перераспределению удельных нагрузок в парах трения ленточно-колодочного тормоза и, как следствие, остановке тормозного шкива 1, что способствует размыканию внутренних пар трения тормоза.The tape brake operates as follows. When you press the control lever 6, the brake closes. In this case, the brake tape 4 with the linings 7 interact with the working surface of the brake pulley 1 with its middle part of the grasping arc, after which the front of interaction extends to the oncoming branch (I) of the tape 4 and its branch (II). At the same time, in friction pairs "working surface 8 of the lining 7 - the working surface of the brake pulley 1" friction

, the main component of which is the dynamic coefficient of sliding friction (f _C ). In addition, between the inner surface of the brake tape 4 and the idle surface 9 of the lining 7 there is a static friction force F _P. In this case, it is necessary to take into account the fact that the cleanliness of the inner surface of the brake belt 4 corresponds to the cleanliness of the surface of the brake pulley 1, and the working 8 and idle 9 surfaces of the linings 7 are processed and have the same roughness before they are installed on the belt 4. At some point in time of braking with an increase in the applied force to the control lever 6, the total forces

and F _P in the plates 7 overcome the resistance forces acting on the sections of closed 22 and open 23 loops in the system of holes 14 of the plates 7 and holes 15 in the tape 4, in the grooves 19 of the bushings 18 and the interaction of their outer surfaces with the surfaces of the depressions 16 and antennae 20 on the brake belt 4, which causes the rotation of the bushings 18 and, as a consequence, the movement of the friction linings 7 on the branches I and II of the brake tape 4. The latter will contribute to the dynamic redistribution of specific loads in the friction pairs of the tape-brake and As a result, the brake pulley 1 stops, which helps to open the internal friction pairs of the brake.

During braking, the sections of closed 22 and open 23 circuits of the ropes are stretched, which leads to their lengthening and, as a result, sagging of the linings 7. In this case, using the control handle 30, the tension of closed 22 and open 23 circuits of the ropes is ensured, which contributes to the complete the fit of non-working surfaces 9 of the pads 7 to the inner surface of the tape 4. With subsequent use of the brake, the braking stages are repeated.

Thus, the use of a tape-shoe brake can increase the braking efficiency by creating resistance to the movement of the lining along the branches of the brake belt relative to the working surface of the pulley and the inner surface of the belt, redistributing and equalizing the specific loads on the arches of the grip of the brake belt and thereby contributing to almost uniform wear working and non-working surfaces of the pads.

Information sources

1. Patent of Russia 2263832 C2, IPC ⁷ F16D 49/08 from 10.11.2005, [analog].

2. Application for a patent of Russia No. 2009138645/11 of 10.19.2009, [prototype].

Claims (2)

1. A tape-brake brake containing a brake pulley on the shaft and a brake tape with friction linings installed on its ramp and run branches with a variable pitch increasing from the ramp running to the run down branch, connected on the tape branches by ropes of different stiffness, passed through holes in the tape, located on its edges, and in the friction linings along their width, ensuring their independent movement on the branches of the tape, as well as the control drive of the cable lining system and mechanical water brake, characterized in that on the branches of the brake tape along the length of the lining displacement grooves are made, in which bushings are installed, having continuous thickenings at their ends, made in the form of blocks enveloped by sections of ropes and pressed down by antennae, while the entire rope of the oncoming branch It is made in the form of a closed loop, and its sections are brought into the volumes of fixed bushings located at the beginning and at the end of the oncoming branch of the tape, and in the volume of the last of them, the sections of the ropes of the oncoming and running branches are connected between wallpaper, and at the same time on the runaway branch of the tape, the rope is made in the form of an open loop with independent ends. 2. The tape-brake brake according to claim 1, characterized in that in the friction pairs of the brake “pad-pulley” and “pad-tape” tension of the contours of the ropes is achieved due to the fact that the independent ends of the ropes are connected to the fixed ropes through the rollers with fixed axles the pins of the rotatable cam, made at the same time with the handle for controlling the tension of the contours of the ropes, ensuring the movement of the friction linings on the branches of the brake belt relative to the working surface of the brake pulley for dynamic equalization of specific loads of external and internal brake friction pairs.

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