Band-shoe brake with combined band of draw works

FIELD: machine building.

SUBSTANCE: invention relates to machine building, particularly, to draw works band-shape brakes. Proposed brake comprises brake pulley on the shaft and extra brake band with friction discs and the main brake band arranged there under and brake control drive. Note here that their leading edges are secured to equaliser and crankshaft crank pin. The main brake shoe features stiffness varying in length, maximum stiffness is at place nearby band attachment to crank pin and minimum stiffness is at band free end nearby equaliser. Extra brake band narrow free end is secured by pliable ear to the main brake band at the end adjoining the crankshaft crank pins. Surfaces of the main and extra brake bands are interconnected by strong but pliable vulcanised-on layer of nanomaterial.

EFFECT: decreased irregularity of distribution of specific loads in friction pairs "friction disc - pulley".

2 cl, 8 dwg

The invention relates to mechanical engineering and can be used in the tape-drum brakes drilling winches.

Known tape-drum brake in which to ensure uniform wear of the friction linings of the latter are located on the working surface of the brake pulley and is provided with an elastic elements connecting them together and banana to the working surface of the pulley, and the dynamic coefficient of sliding friction between the outer surface of the lining and the inner surface of the brake belt is greater than that between the working surface of the lining and the brake pulley [1, similar]. The disadvantage is that you must have friction materials with different dynamic coefficients of sliding friction for the outer and inner surfaces of the plates.

In addition, the brake band is exposed not only dynamic, and thermal loads.

Famous band-Shoe brake with movable friction linings, which contains a separate stationary pads at the beginning of the incoming branch of the brake bands, in the middle of the tape and at the end of the cascading branches of the tape and between the fixed plates are moving pads, which in its upper part by their width have openings planted in the l-shaped grooves of the tape, with movable pads have who is very useful move relative to the inner surface of the tape and the working surface of the pulley, and rolling and cascading branches tape is different in the number of moving plates that are connected together with springs of different stiffness [2, prototype). The disadvantage is that in the interaction of the outer movable friction lining to the inner surface of the brake belt is not implemented large factor of their mutual overlap.

The proposed solution in comparison with analogue and prototype has the following distinctive features:

the main brake band has a variable stiffness due to the different thickness and absence in her body stress concentrators;

- use the surface of the brake master tape and the outer surfaces of the friction pads as additional areas of the contact friction;

- no cascading branches on the brake the tape, but the presence of a combined brake tape two incoming branches that will substantially reduce their ratio of tensile and shear effort, i.e. S_H1/S_H2(where S_H1, S_H2the tension of the incoming branches of the primary and secondary brake bands);

- the use of durable and elastic layer of nanomaterial used for connection of the surfaces of the primary and secondary brake bands to reduce the difference between the forces of tension of their plots, and, as the consequence, eliminate uneven distribution of specific loads across the width of the friction lining.

The objective of the invention is improving the efficiency of the brakes for the purposeful use of a combined brake belt tensile plots the primary and secondary brake bands if each of them only incoming branches and the shear layer of nanomaterial, and also due to additional zones of interaction to obtain multi-pair of friction during braking.

This objective is achieved in that the main brake band performed with variable stiffness along the length, which is the maximum in place, bordering on fixing it to the crank necks of a cranked shaft, and a minimum at the free end of the tape at the balancer and additional brake band its free end attached pliable the weft to the main brake line at the end, bordering motilium tails of the crankshaft, and the surface of the tape is connected between a strong but pliable pereformirovana layer of nanomaterial.

When this condition health combined brake bands when implementing the tension of the rolling main branches (S_H1) and secondary (S_H2ribbons are dependencies

$$q_{1}f1>S_{H1};\left(1\right)$$$$q_2{f}_2>S_{H2},\left(2\right)$$

where q₁, q₂- contact force of the surfaces of the primary and secondary brake bands with surfaces reformirovanija thereto a layer of nanomaterial;

f₁f₂static coefficients of friction of rest when interacting surfaces of a layer of nanomaterial with the surfaces of the primary and secondary brake bands; and arising at the boundaries of the interaction of the surface layer of the nanomaterial with the surfaces of the primary and secondary brake bands shear stresses (τ₁and τ₂) must not exceed the specific force of static friction occurs when shear deformation, ie,

$$t_1<\frac{q_1{f}_1}{b_1{l}_1};\left(3\right)$$

where b₁b₂- the width of the primary and secondary brake bands;

l₁, l₂- the length of the surface of interaction between the primary and secondary brake bands with a surface layer of nanomaterial.

Figure 1 shows the kinematic diagram of the drawworks with band brake Shoe; figure 2 is a kinematic diagram of the belt-plate brake combined tape; figure 3 is a transverse section of figure 2 along a-a; figure 4 shows the fastening eyelet additional brake bands; figure 5 and 6 illustrates the mounting of the transverse and longitudinal grooves of the primary and secondary brake bands; 7 combined brake band with the sprung snatch devices with serial friction lining; on Fig the scheme pre-mixed (first and second kind) brake master tape relative to the additional brake belt.

Following symbols are used: R_WD_W- the radius and the diameter of the working surface of the brake pulley;

r is the radius of the crank of the crankshaft; ω - angular speed of rotation of the pulley;

φ, α angles of circumference one and all nakedc the mi of the working surface of the brake pulley;

S_H1, S_H2the tension of the incoming branches of the primary and secondary brake bands;

F_Pthe force applied by an operator to the control lever brake;

q₁, q₂- contact force of the surfaces of the primary and secondary brake bands with surfaces reformirovanija thereto a layer of nanomaterial;

q₁f₁and q₂f₂- contact force of static friction in the interaction surfaces of the primary and secondary brake bands with surfaces reformirovanija thereto a layer of nanomaterial;

f₁f₂static coefficients of friction of rest when interacting surfaces of a layer of nanomaterial in the combined brake the tape from its surface.

l_y.o., l_UD- the lengths of segments of the primary and secondary bands at angles α_WOand α_UDtheir elastic deformation;

l_OTO, l_und- the lengths of segments of the primary and secondary bands at angles α_OTOand α_undpreliminary displacement of the first kind;

l_nthe lengths of the main and additional tapes on the corner of peace α_n;

l_p.o., l_rd- the lengths of segments of the primary and secondary belts forming the main work areas;

l_Octo, l_old- the lengths of segments of the primary and secondary belts, almyroudis residual zone;

γ_{d o.}that γ_{d D.}- maximum shear strain in the zone of relative peace.

According to the kinematic diagram (see figure 1) friction lining 3 is installed on the brake bands 2 that one end side cascading branches tape attached to the balancer 11 and the other (by rolling its branches) to crank necks 6 and 9 of the crankshaft 10.

Serial tape-plate brake drawworks work as follows. The handle 1 is the rotation of the crankshaft 10, in which the driller pulls the brake belt 2 with a friction lining 3, and they sit down on the brake pulley 4. The process of the brake band brake Shoe (see figure 1) is characterized by the following stages: initial (first), intermediate (second) and the final (third). Stop at each of the stages separately.

At the initial stage of the brake friction lining 3, placed in the middle part of the brake bands 2, interact with the working surface of the brake pulley 4. Front interaction extends in the direction of the friction lining 3 incident branches of brake bands 2.

Intermediate stage of braking is characterized by further propagation of the front of the interaction in the direction of the friction lining 3 cascading branches of brake bands 2.

Konecne what I inhibition phase is characterized by almost all stationary plates 3 brake bands 2 interact with the working surface of the rotating pulley 4. During snubbing the sequence of occurrence of the friction surfaces in contact is repeated. Full cycle braking ends with a stop brake pulley 4 and the drum 5. The brake control drawworks shall also undertake the supply of compressed air through the valve 7 driller in the pneumatic cylinder 8, the piston rod of which is connected to one of Motulevich necks 6 of the crankshaft 10 of the brake. The pressure of the compressed air in the pneumatic cylinder 8 regulate the rotation of the crane 7 driller.

Uneven wear of the friction lining 3 installed on the tape 2, the balancer 11 at the time of deceleration deviates somewhat from the horizontal position and aligns the load on cascading branches of brake bands 2, while providing a uniform and simultaneous girth they brake pulley 4. Thanks to the ball joint implementation loads from the brake bands 2 to the balancer 11 is not changed.

The weakest link in the brake node are friction linings. They are manufactured as separate parts, which can be fastened in various ways (for example, using bars) relative to the flexible steel tape. When installing the ribbon plates with constant pitch their number is always even (12; 16; 18; 20; 22; 26).

Band-Shoe brake drawworks includes a combined brake tape, which consists of a core 12 and an additional 15 brake bands. Brake master tape 12 with a variable thickness of its incident ends are attached to the crank necks 6 and 9 of the crankshaft 10, near which their stiffness (C_in) is maximum. While rolling the ends of the additional tape 15 is attached to the walking beam 11, and enters the ends have ears 16 that are transverse grooves 17 between which there is a partition at the incident end of the brake master tape 12, and are attached to the free ends of the additional brake bands 15 by bolts 18. The main brake band 12 has monospitovo 13 outer and smooth inner surface 14. Additional brake band 15 with its inner surface 16 has sides longitudinal grooves 19 of the same cross section and length. Between an inner surface 16 additional brake bands 15 and conocephalinae the outer surface 13 of the main brake bands 12 are connected sformirovannym durable and elastic layer of nanomaterial 20.

In the middle of each of the longitudinal grooves 19 additional tape 15 wound the tabs of the mounting plates 21, which are reinforced by a wire 22 in the body serial frictional NAC is adok 23, having outer 24 and 25 working surface.

For tripping composite brake tape after braking are sprung snatch device 25, which is attached to the additional brake the tape 15.

Thus, in the combined brake tape implement the principle unloading brake master tape 12 by removing from her body stress concentrators (holes: under rivets for fastening the spacer strips for straps; for fixing the resilient rings snatch devices; longitudinal grooves under the mounting strap overlays). This increases the total deformation of the rolling main branches 12 and 15 additional brake bands and, consequently, will S_H1-S_H2more, i.e. the friction force on the interacting surfaces and the generated braking torque. This provides good flexibility brake master tape 12 when the regulated factor of safety.

Additional brake band 15 provides fastening serial friction pads 23, and the gap between the pairs of friction "cover - pulley" by attaching to it a spring snatch device 26.

Combined brake band carries only the weight load from the production of friction linings 23.

During operation of the tape-drum brakes combined with the new ribbon drawworks have the following areas of cooperation: "the inner surface 14 of the main brake bands 12 - the outer surface 24 of the friction pads 23 and the working surface 25 of the friction lining 23 - working surface of the brake pulley 4".

Condition of health in the combined brake and tape are formed in pairs of friction due to the almost motionless serial friction lining 23 is the following. Dynamic coefficients of friction in the friction nodes: "working surface of the brake pulley 4 - working surfaces 25 pads 23"; "the inner surface 14 of the main brake belt 12 to the outer surface 24 of the plates 23" should be the same. For this purpose, the purity of the 13 outer and inner surfaces 14 of the main brake belt 12 should be the same as the surface of the brake pulley 4. In addition, the outer surface 24 of the plates 23 must be machined so that the microgeometry was the same with the micro geometry of their working surfaces 25. As for the contact of static friction between the tapered outer surface 13 of the main brake belt 12 and the lower surface layer of nanomaterial 20 and its upper surface and the inner surface 16 of the additional brake belt 15, it is important to note the following. According pig when the circuit brakes within zones of elasticity occurs a displacement of the brake bands, the base 12 relative to the additional 15 in the S_H1/S_H2>1.0, and also due to the presence between them reformirovanija to their surfaces elastic and pliable layer of nanomaterial 20. It must comply with the condition q₁f₁>SH₁and q₂f₂>S_H2. When the violation of one of the conditions will fail zones of contact interaction, and the layer of nanomaterial 20 will lose their binding ability between the main surfaces 12 and 15 additional brake bands. In addition, occur at the boundaries of the interaction layer of nanomaterial 20 with the surfaces of the brake bands shear stresses shall not exceed the specific force of static friction occurs when shear deformation, ie,

$$t_1<\frac{q_1{f}_1}{b_1{l}_1}$$and$$t_2<\frac{q_2{f}_2}{b_2{l}_2}$$,

where l₁and l₂- the length of the surface of interaction between the primary and secondary brake bands with a surface layer of nanomaterial.

Consider the three-dimensional physical model core 12 and an additional 15 is almaznyh tapes.

According pig by the end of the incoming branch of the brake master tape 12 is applied tensile stress S_H1that does not exceed the full force of static friction between conocephalinae the outer surface 13 of the main brake band 12 and the inner surface pereformirovana durable and elastic layer of nanomaterial 20. By the end of the incoming branches of the additional brake tape applied tensile stress S_H2that does not exceed the full force of static friction between the inner surface 16 of the additional brake bands 15 and the outer surface reformirovanija durable and elastic layer of nanomaterial 20. At the time of application of tensile load S_H1and S_H2there is preliminary shifting of the second kind on the ends of the contact friction of rest, represented by zones of elastic strain l_U.O.and l_UDwithin which gradually builds up torque eplanations shift. Next to the center contact of friction relative peace spread area l_OTOand l_undwith the prior offset of the first kind, at the end of which the deformation deplanting shift in the elastic main sections 12 and 15 additional brake bands gradually fade, and in the center of the contact friction of rest a zone of complete rest l_nto which there is no deformation or the Nations and there is no transfer of tensile load S _H1and S_H2on the contact friction of rest. Zone of elastic strain l_y.o.and l_UDyou can identify with that part of the tension S_H1and S_H2passed on the contact friction of rest due to the zones l_OTOand l_und

$$l_{y.\mathrm{about}.}=\frac{k_1{S}_{H1}}{q_1{f}_1{b}_1\left(1+\frac{{\mathrm{with\; a}}_{\mathrm{about}.}}{{\mathrm{with\; a}}_{d.}}\right)};\left(5\right)$$$$l_{y.d.}=\frac{k_2{S}_{H2}}{q_2{f}_2{b}_2\left(1+\frac{{\mathrm{with\; a}}_{d.}}{{\mathrm{with\; a}}_{\mathrm{about}.}}\right)},\left(6\right)$$

where b₁b₂- the width of the primary and secondary brake bands;

with_aboutand C_d- given and permanent hardness is the main and additional brake bands, taking into account the offset on the contact friction of rest, derived from the joint action of tensile deformations and deplanting shift;

k₁and k₂- coefficient taking into account what portion of the tensile load S_H1and S_H2transferred in elastic zone. The value of k depends on the thickness of the core (h₁) (shown) and additional (h₂) (permanent) brake bands, their surfaces interact with surfaces durable and elastic reformirovanija layer of nanomaterial. According to equations (5) and (6) we get

$$k_1{S}_{H1}+k_2{S}_{H2}=q_1{f}_1{b}_1{l}_{y.\mathrm{about}.}+q_2{f}_2{b}_2{l}_{y.d.}.\left(7\right)$$

Therefore, within the contact friction of rest along with elastic zones where there is a prior offset of the second kind, always there is a zone of relative quiescence, with very little prior offset of the first kind.

Analyzing equations (1)-(3), we see that the length of the elastic zones depends on the ratio of the reduced stiffness of the primary and permanent hardness of additional brake bands and their thickness. According to the constructive characteristics of the combined brake tape_about>with_dthe length of the elastic zone of the main tape l_U.O.will be small. The incremental shear delenatii variables and constant cross sections in elastic sections of the primary and secondary brake bands are distributed in a zone of relative quiescence, l_OTPand within it reaches its maximum value γ_do.(see Fig). The accumulation of shear deplanting deformation depends on the magnitude of the eccentricity of application of tensile load S_H1and S_H2of squares of the interaction surfaces of the primary and secondary brake bands with pereformirovana to them with a layer of durable and pliable nanomaterials, as well as from the structural parameters of the cross-section of the considered sections of the ribbons. The area within which depleation shear stresses in elastic tapes are growing, and where it is passed to the main tensile stress, let's call the main working area l_p.o.and the area where transmitted relatively small part of the tensile force due to decreasing deformation deplanting shift, residual area l_leave(see Fig). Due to the fact that the rigidity of the brake master tape is great compared to the static stiffness updat the additional brake bands, the main working area l_endit is almost equal to the elastic area l_U.O.and the residual area l_Octozone of relative quiescence, l_OTP.

Thus, the energy accumulation of tensile deformations in the oncoming branches of the primary and secondary brake lines and energy shear strain in the layer of nanomaterial ultimately leads to decrease tension S_H1and S_H2.

Band-Shoe brake combined tape works as follows. The handle 1 is the rotation of the crankshaft 10, in which the driller pulls the core 12 and an additional 15 brake bands, and the circuit brakes. The energy of the tension generated forces (S_H1and S_H2) incoming main branches 12 and 15 additional brake bands, is expended to overcome the total of all the forces of static friction between conocephalinae the outer surface 13 of the main brake belt 12 and the inner surface reformirovanija durable and elastic layer of nanomaterial 20 on the one hand and on the other between the inner surface 16 of the additional brake bands 15 and the outer surface reformirovanija durable and elastic layer of nanomaterial 20. In addition, the difference in tension (S_H1-S_H2) incoming branches on the main 12 and 15 additional brake bands spent on deformation deplanting shift due to the flexibility of the layer, made of nanomaterial 20, plots brake master tape 12 relative to plots additional brake bands 15. The resulting strain energy from the efforts of a tension S_H1and S_H2accumulated in the branches of a combined brake bands in the future is to move sections of the main tape 12 relative to plots additional tape 15 and reduces the difference of the forces of tension sections of the ribbons 12 and 15, and consequently, reduction of spikes of unit loads in pairs of friction surfaces 25 of the friction lining 23 - working surface of the brake pulley 4".

Due to the variable pliability plots brake master tape 12 is the interaction of its internal surface 14 with the outer surfaces 24 of the friction lining 23 which leads to a total force of static friction F_n. The greatest efficiency has a pair of friction surfaces 25 of the friction lining 23 - working surface of the brake pulley 4"contributing to the emergence of the friction force F_Tthe main component of which is the dynamic friction coefficient (f_d).

At some point, the temporary inhibition with increase in applied force to the control lever 1, the total force F_Tand F_nwill stop brake drum drawworks. In a further stage of the brake band brake Shoe combined brake band again.

Thus, through the use of a combined brake belt and interconnected durable and pliable layer of nanomaterial surfaces of the main and additional tapes in the tape-drum brake drawworks implemented the principle of two incoming branches of the brake bands, not with cascading branches, as well as pairs of friction between the inner surface of the main belt with variable stiffness and outside surfaces of the friction lining, which significantly reduces the uneven distribution of unit loads in friction pairs "cover - pulley and increases the efficiency of the friction units of the brakes due to the additional friction pairs.

Sources of information

1. As the USSR 576455 A1, F15d 49/08 from 15.10.1977, (similar).

2. Patent of Russia 2263832 C2, IPC⁷F16D 49/08 from 10.11.2005, (prototype).

1. Band-Shoe brake combined tape drawworks containing brake pulley on the shaft and additional brake the tape with the attached friction pads, located underneath the main brake the tape and the lapping ends attached respectively to the balancer and crank necks of a cranked shaft, and the drive control brake, otlichuy is the, that the brake band is made with a variable stiffness along the length, which is the maximum in the place bordering the fastening tape to crank necks of a cranked shaft and a minimum at the free end of the tape at the balancer and additional brake band its narrowed free end attached to the pliable appendage to the main brake line at the end, bordering motilium tails of the crankshaft, and the surface of the primary and secondary brake bands are interconnected sturdy but pliable pereformirovana layer of nanomaterial.

2. Band-Shoe brake combined tape drawworks according to claim 1, characterized in that the health condition of the combined brake bands when implementing the tension of the rolling main branches (S_H1) and secondary (S_H2ribbons are the dependencies:

whereq₁, q₂- contact force of the surfaces of the primary and secondary brake bands with surfaces reformirovanija thereto a layer of nanomaterial;
f₁f₂static coefficients of friction of rest when interacting surfaces of a layer of nanomaterial with the surfaces of the primary and secondary brake bands; and arise when the volume on the interop boundary surfaces of the layer of nanomaterial with the surfaces of the primary and secondary brake bands shear stresses ( τ₁andτ₂) must not exceed the specific force of static friction occurs when shear deformation, i.e

whereb₁b₂- the width of the primary and secondary brake bands;
l₁l₂- the length of the surface of interaction between the primary and secondary brake bands with a surface layer of nanomaterial.