CN103352706B - Method for designing center bigeminal hobs of heading machine - Google Patents

Abstract

The invention provides a method for designing center bigeminal hobs of a heading machine, belongs to the technical field of mechanical equipment for tunnel construction, relates to cutters and in particular relates to a method for designing center bigeminal hobs, adopting a sliding support, of a heading machine. The method comprises the following steps: respectively mounting radial sliding bearings in the central positions of the inner surfaces of cutter bodies according to the whole technical performance and the construction requirement of the hobs under the conditions of guaranteeing sufficient strength and rigidity of the center bigeminal hobs; respectively mounting cylindrical roller thrust bearings at the positions, near end covers, of the radial sliding bearings; and mounting trapezoidal sealing rings at the cooperative positions of the cutter bodies, the end covers and double-sided end covers, and setting floating seal in sealed spaces formed by the cutter bodies, the thrust bearings and the end covers. The combined form of thrust roller bearings, the end covers and shaft end check rings is adopted in the axial direction, so the strength, rigidity and stability of the hobs are improved; and the two sets of sliding bearings are mounted in the radial direction, so good shock resistance and vibration-absorbing property are achieved, vibration and damage of cutter heads are reduced, the service lives of the hobs are prolonged, and the reliability of the cutter heads supporting and propelling system is improved.

Description

A kind of development machine center bigeminy hobboing cutter method for designing

Technical field:

The invention belongs to technical field of mechanical equipment for tunnel construction, relate to a kind of cutter, particularly a kind of method for designing of development machine center bigeminy hobboing cutter of sliding support.

Background technology:

Flange-type hob is as the topmost cutting element of full face rock tunnel boring machine, under the complexity of the high strength of massif, tunnel rock, high rigidity and geological conditions and boring machine cutter be operated in strong extruding, high pulling torque, thump, high bad working environments of wearing and tearing, boring machine cutter is made to become the most flimsy component in tunneling process.Cutterhead central space is limited, most of cutter head center positions mounting center bigeminy or multi-joint hobboing cutter, because central hob position is special, rotating speed is lower but stressed very complicated, is often subject to powerful shock and vibration, causes cutter hub play, bearing damage and seal failure in rock break-off process, greatly reduce the life-span of hobboing cutter, and the vibration that hobboing cutter bears and impact and be delivered to cutterhead by cutter shaft, causes vibration and the damage of cutterhead, and then affect the reliability of the support of cutterhead, propelling and rotary system.

In the multi-joint hobboing cutter design of conventional center, what play revolving support effect to cutter ring and cutter hub is the taper roll bearing of the back-to-back installation of two row, because this pair taper roll bearing can bear very large radial load and axial load simultaneously, be widely used in rock ripper hob-cutter structure.China Patent No.: 201120558297.5, patent name is: the narrow central hob of split, the vigorous De Yuehanlai of inventor rises to receive and provides the narrow central hob of a kind of split, comprise hobboing cutter body and annular tool rest, the lateral surface of described hobboing cutter body is provided with draw-in groove, and described annular tool rest has abutted C shape collar with clamping between described draw-in groove.China Patent No.: 201120258547.3, patent name is: a kind of double disk shaped central hob for shield machine, and the people such as inventor Li Wei provide a kind of double disk shaped central hob for shield machine, and cutter ring hardness reaches HRC55-58, tensile strength reaches 2000MPa, wear-resisting, durable; Reduce the labour intensity of workman simultaneously; Invest low, construction application is in extensive range.Vigorous De Yuehanlai is risen and receives write patent and facilitated the operation such as replacing, installation of hobboing cutter cutter hub by annular tool rest and C shape collar, improves efficiency; The people such as Li Wei write patent the abrasion resistance of cutter ring and the sealing of hobboing cutter be greatly improved, but the shock resistance and the shock attenuation result that reckon without two row cone rollings in patent are poor, the operating mode of rock ripper is more severe again simultaneously, the powerful shock and vibration that hobboing cutter usually will bear, hobboing cutter often excessively causes bearing and seal failure because vibrating and scraps in advance, and hobboing cutter vibrates excessive tool setting dish and cutterhead propulsion system also has certain damage.Therefore still there is the defect of the more weak and shock attenuation result difference of impact resistance in the novel central hob of foregoing invention.

Summary of the invention

The technical barrier that the present invention will solve overcomes the deficiencies in the prior art, invent a kind of development machine center bigeminy hobboing cutter method for designing of sliding support, this method for designing makes central hob under operating mode complicated and changeable, greater impact and vibration can be born, improve hobboing cutter, the application life of cutterhead and the reliability of cutterhead propulsion system.

The technical solution used in the present invention is the method for designing of a kind of development machine center bigeminy hobboing cutter, the method considers center bigeminy hobboing cutter overall technology performance and construction requirement, in the cutter hub 7 inner surface center of central hob, bush(ing) bearing 5 is installed respectively, at one end respectively symmetrical installed thrust cylinder roller bearing 3 of bush(ing) bearing 5 by end cap 4; First carry out the determination of bush(ing) bearing 5 and cylindrical roller thrust bearing 3 type selecting, design and lubricating system, and then complete the design of center bigeminy hobboing cutter dependency structure, specific design method is as follows:

1) central hob is arranged on cutter head center position, hard rock mole cutterhead maximum (top) speed is approximately 8r/min, the maximum (top) speed being then arranged on the hobboing cutter of cutter head center is approximately 26r/min, and the maximum radial load of bearing in hobboing cutter rock break-off process can reach more than 200KN, therefore central hob rock break-off process belongs to low-speed heave-load operating mode; The relative rotation speed of hobboing cutter cutter hub inner ring and cutter shaft axle journal is lower (about 0.15m/s), and intermittent work, be difficult to form continuous print dynamic pressure oil film, therefore be not suitable for the sliding bearing of fully liquid lubrication; Central hob operating mode is severe, is difficult to frequent fuel feeding, and sliding agent is added in inconvenience, therefore the sliding support parts of central hob are incomplete hydrodynamic lubrication bush(ing) bearing 5, and lubricating system is grease lubrication; According to the ultimate load that size and the hobboing cutter of cutter shaft 1, cutter hub 7 bear, and P, V and PV value of bush(ing) bearing is checked, determine the axle journal D of sliding bearing and the width B of bearing holder (housing, cover), thus finally determine the model of bush(ing) bearing 5, physical dimension and installation dimension;

2) after determining bush(ing) bearing 5 structure, then according to the physical dimension of cutter hub and cutter shaft, obtain the width of cylindrical roller thrust bearing 3 and the diameter of inner ring, simultaneously according to the limit axial load of hobboing cutter, thus determine the model of cylindrical roller thrust bearing 3;

Selection for the lubricating system of cylindrical roller thrust bearing 3: the strength of lubricant film of lubricating grease is high, can bear larger load, not easily run off, easy sealing, and be only applicable to lower dn value (40000mmr/min is not more than for thrust roller bearing); And center bigeminy hobboing cutter rotating speed lower (about 2600mmr/min), and the lubricating system of sliding bearing is grease lubrication, therefore the lubricating system of selected cylindrical roller thrust bearing 3 is grease lubrication;

3) after the model of bush(ing) bearing 5 and cylindrical roller thrust bearing 3, lubricating system, physical dimension and installation dimension obtain determining, and then the design of the associated structural component such as cutter hub 7, cutter shaft 1, cutter ring 8, snap ring 6, end cap 4, shaft end ring 2, O RunddichtringO 11 and metal floating ring 12 is completed;

Described a kind of development machine center bigeminy hobboing cutter method for designing, it is characterized in that, the bigeminy central hob that this method for designing adopts is made up of cutter shaft 1, shaft end ring 2, cylindrical roller thrust bearing 3, end cap 4, bush(ing) bearing 5, snap ring 6, cutter hub 7, cutter ring 8, two-sided end cap 9, ladder-shaped sealing ring 10, O RunddichtringO 11 and metal floating ring 12; Described cutter ring 8 hot charging on cutter hub 7 outer ring, and is buckled in the outer ring annular groove inner position of cutter hub 7 by snap ring; Bush(ing) bearing 5 is in the center of cutter hub 7, and the solid box of bush(ing) bearing 5 is embedded in cutter hub 8 inner surface center; Two cover thrust roller bearing 3 symmetries are arranged on the both sides of bush(ing) bearing 6, the dynamic lasso of thrust roller bearing 3 and cutter hub 7 interference fit, thrust roller bearing 3 determine lasso and cutter shaft 1 interference fit, and cutter shaft 1 two ends have end cap 4 to locate; Cutter shaft 1 arranges shaft end ring 2 without the axle head of shaft shoulder location; Ladder-shaped sealing ring 10 is installed in end cap 2 and cutter hub 7 junction; Symmetrical mounting O-shaped sealing ring 11 and metal floating ring 12 in the space that cutter hub 7, cylindrical roller thrust bearing 3 and end cap 4 are formed.

The beneficial effect that the present invention has is: center bigeminy hobboing cutter cutter hub 7 structure is simple, and processing and manufacturing is more convenient with assembling; At end cap 4 and cutter hub 7 cooperation place, trapezoidal rubber ring 10 is installed, substantially increases the sealing of hobboing cutter entirety; Two cover cylindrical roller thrust bearing 3, axial back-up ring 2 and end cap 4 combining forms at cutter shaft 1 two ends improve the ability of cutter axial load resistant, reduce axial displacement and vibration; Two cover bush(ing) bearings 5 have certain vibration absorption ability, reduce the shock and vibration of cutter shaft 1 to a great extent, and then reduce vibration and the damage of cutterhead, improve the reliability of central hob and cutter head support propulsion system.Improve hobboing cutter axial rigidity and vibration absorption ability, reduce the vibration of hobboing cutter and cutterhead, improve cutter life and cutter head support propulsion system reliability.

Accompanying drawing explanation

Fig. 1 is hobboing cutter overall structure schematic diagram of the present invention.In figure: 1, cutter shaft; 2, shaft end ring; 3, cylindrical roller thrust bearing; 4, end cap; 5, bush(ing) bearing; 6, snap ring; 7, cutter hub; 8, cutter ring; 9, two-sided end cap; 10, ladder-shaped sealing ring; 11, O RunddichtringO; 12, metal floating ring.

Specific embodiment

Specific embodiment of the invention is described in detail by reference to the accompanying drawings with technical scheme.Full face rock tunnel boring machine in the course of the work, under central hob is subject to radial direction, axis and moment shock loading, wherein radial load is that hobboing cutter bears peak load direction, the vibration of hobboing cutter is caused under this associating shock loading, thus cause seal failure, bearing damage, greatly reduce the life-span of hobboing cutter; Simultaneously hobboing cutter cutter shaft is fixed on cutterhead, and the shock and vibration that cutter shaft is subject to are directly delivered to cutterhead, causes the reliability of the damage of cutterhead and cutter head support, propelling and rotary system.In order to reduce the vibration of central hob and cutterhead, the shock and vibration reducing central hob radial direction must be managed, increase simultaneously cutter shaft to rigidity of toppling.And the rotation supporting structure of central hob the most frequently used at present adopts is two row tapered roller bearings of back-to-back installation, and the impact resistance of taper roll bearing is more weak, and axial rigidity is less compared with cylinder roller bearing.

At present, hard rock mole cutterhead maximum (top) speed is approximately 8r/min, the maximum (top) speed being then arranged on the hobboing cutter of cutter head center is approximately 26r/min, and the maximum radial load of bearing in hobboing cutter rock break-off process can reach more than 200kN, therefore central hob rock break-off process belongs to low-speed heave-load operating mode; The relative rotation speed of hobboing cutter cutter hub inner ring and cutter shaft axle journal is lower (about 0.15m/s), and intermittent work, be difficult to form continuous print dynamic pressure oil film, therefore be not suitable for the sliding bearing of fully liquid lubrication; Central hob operating mode is severe, is difficult to frequent fuel feeding, and sliding agent is added in inconvenience, therefore the sliding support parts of central hob are incomplete hydrodynamic lubrication.Selection for the lubricating system of cylindrical roller thrust bearing (3): the strength of lubricant film of lubricating grease is high, can bear larger load, not easily runs off, easily seals, and be only applicable to lower dn value; And center bigeminy hobboing cutter rotating speed is lower, and the lubricating system of sliding bearing is grease lubrication, therefore the lubricating system of selected cylindrical roller thrust bearing (3) is grease lubrication.

The present invention is directed to the defect that current central hob still exists the more weak and shock attenuation result difference of impact resistance, in cutter hub inner surface center, bush(ing) bearing is installed respectively; Install two cover cylindrical roller thrust bearings in the both sides of bush(ing) bearing symmetry, the moving-coil of thrust bearing and cutter hub interference fit, fixed circle and cutter shaft interference fit, concrete structure schematic diagram as shown in Figure 1.The present invention adopts two cover sliding bearings and two cover thrust bearings combination forms to improve the intensity of hobboing cutter, rigidity and stability; The sliding bearing that hobboing cutter radial direction is installed has good shock resistance and absorbing, reduces vibration and the damage of cutter shaft and cutterhead; Thus improve the life-span of hobboing cutter and the reliability of cutter head support propulsion system.The present invention is equally applicable to center bigeminy, tetrad, eight hobboing cutters and cutter of backbreaking, and illustrates the method for designing of central hob of the present invention below for 17 cun of center bigeminy hobboing cutters:

1) Selection and Design of bush(ing) bearing

In order to make the hobboing cutter of design economic and practical, sliding bearing and cutter bearing are tried one's best choice criteria part, and low speed heavy-duty bearing, be improve bearing integral rigidity, should higher value be got.In conjunction with the physical dimension having now 17 cun of central hob cutter shafts and hobboing cutter entirety, first stationary knife shaft neck is 120mm, and plain journal bearing width is 100mm.

Cutterhead rotating speed is set to n _cutterhead=8r/min, cutter diameter d=0.432m; Utilize the linear velocity of hobboing cutter and cutterhead contact point equal, calculate the linear velocity of this place's hobboing cutter, the footpath, pole apart from cutter head center central hob is farthest approximately 0.705m, tries to achieve the rotating speed n=21.6r/min of this hobboing cutter;

The peripheral speed of axle journal is:

$\mathrm{\υ}=\frac{\mathrm{\πdn}}{60\×1000}=\frac{\mathrm{\π}\×120\×26.1}{60\×1000}=0.164m/s$

The relative gap of bearing is:

$\mathrm{\ψ}=\frac{{(n/60)}^{4/9}}{{10}^{31/9}}=\frac{{(21.6/60)}^{4/9}}{{10}^{31/9}}=2.28\×{10}^{-4}\mathrm{mm}$

Just estimate the dynamic viscosity of oil:

$\mathrm{\η}=\frac{{(n/60)}^{-1/3}}{{10}^{7/6}}=\frac{{(26.1/60)}^{-1/3}}{{10}^{7/6}}=0.09\mathrm{Pa}\·s$

Therefore can bearing capacity factor be obtained:

$C_p=\frac{F{\mathrm{\ψ}}^2}{\mathrm{\η\ωdB}}=\frac{F{\mathrm{\ψ}}^2}{2\mathrm{\η\υB}}=\frac{200000\×{(2.28\×{10}^{-4})}^2}{2\×0.09\×0.164\×0.1}=3.522$

Look into the bearing capacity factor table of Finite Width bearing, obtain sliding bearing eccentricity by interpolation:

χ＝0.825

Calculate minimum oil film thickness:

$h_{\min }=\frac{d}{2}\mathrm{\ψ}(1-\mathrm{\χ})=\frac{120}{2}\×2.28\×{10}^{-4}\×(1-0.825)=2.39\mathrm{um}$

Determine axle journal, dead eye surface roughness 10 height, go journal surface roughness grade number to be 0.8 by requirement on machining accuracy, dead eye rough surface grade is 1.6, tables look-up and can obtain:

Axle journal R _z1=3.2um

Dead eye R _z1=6.3um

Get safety factor S and should be more than or equal to 2, calculating oil film thickness allowable is,

[h]＝S(R _Z1+R _Z2)＝2×(3.2+6.3)＝19um

Can obtain from above:

h _min(2.39um)＜[h](19um)

In order to ensure minimum oil film thickness h _minbe enough to the nao-and micro relief flooding axle journal and bearing two surface, realize real fluid friction completely, when safety factor is taken as 2, calculates minimum oil film and should be greater than oil film thickness allowable.But obtain h by above result of calculation _min< [h], therefore functional reliability requirement cannot be met, therefore complete Hydrodynamic Sliding Bearing can not be used.And due to the working condition of hobboing cutter be low-speed heave-load, intermittent work, therefore select incomplete hydrodynamic lubrication, considers that sliding agent is often added in the operating mode more complicated inconvenience of hobboing cutter simultaneously, therefore adopts grease lubrication.

Calculate as outer limits load according to the maximum rated thrust 200kN of 17 cun of central hobs:

The average pressure P of bearing:

$p=\frac{F}{\mathrm{dB}}=\frac{200000}{120\&times;100}=16.7\mathrm{MPa}$

The linear velocity V of axle journal:

$v=\frac{\mathrm{\&pi;dn}}{60\&times;1000}=\frac{\mathrm{\&pi;}\&times;120\&times;26.1}{60\&times;1000}=0.164m/s$

The PV of checking computations bearing:

$\mathrm{pv}=\frac{F}{\mathrm{dB}}\&CenterDot;\frac{\mathrm{\&pi;dn}}{60\&times;1000}=\frac{\mathrm{Fn}}{19100B}=\frac{200000\&times;26.1}{19100\&times;100}=2.733\mathrm{MPa}\&CenterDot;m/s$

Can be obtained by above computational analysis: P>15MPa, v<1m/s, belong to low-speed heave-load operating mode, and Allen's metal ZCuPB30 should be used for heavy-duty bearing, and can bear varying load to impact, maximum allowable value is respectively 25MPa, 12m/s, 30MPam/s, therefore above designing requirement can be met.

2) Selection and Design of thrust bearing

After the model of sliding bearing and lubricating system are determined, can according to the size Selection cylindrical roller thrust bearing of the axle journal of cutter shaft and cutter hub.Be 120mm according to cutter shaft diameter, hobboing cutter maximum axial is approximately 30KN, therefore the model selecting thrust bearing is 81124, basic dynamic load rating is 155KN, meet design requirement, and have sufficient axial rigidity, the operating mode more complicated inconvenience of hobboing cutter often adds sliding agent, and sliding bearing employing is grease lubrication, therefore rolling bearing also adopts sliding bearing lubricating mode.

3) design of hobboing cutter dependency structure

After the physical dimension of bush(ing) bearing and cylindrical roller thrust bearing, lubricating system and installation dimension are determined, and then complete the design of cutter hub, cutter shaft, end cap and shaft end ring, finally at the enclosure space design floating seal that cutter hub, end cap and cylindrical roller thrust bearing are formed, concrete structure is arranged as shown in Figure 1.

By above design, can show that the development machine center bigeminy hobboing cutter of a kind of sliding support of the present invention has the following advantages: center bigeminy hobboing cutter structure of the cutter body is simple, processing and manufacturing is more convenient with assembling; At end cap and cutter hub cooperation place, trapezoidal rubber ring is installed, substantially increases the sealing of hobboing cutter entirety; Cylindrical roller thrust bearing, end cap and shaft end ring combine, and increase the overall axial rigidity of hobboing cutter, thus improve the ability of cutter axial load resistant, reduce axial displacement and the vibration of hobboing cutter, thus improve central hob application life; The bush(ing) bearing that cutter hub inner surface is installed, has certain vibration absorption ability, decreases the vibration of cutter shaft to a great extent, and then reduce vibration and the damage of cutterhead, improve the reliability of cutter head support propulsion system.

Claims (2)

1. a development machine center bigeminy hobboing cutter method for designing, it is characterized in that, the method is according to center bigeminy hobboing cutter overall technology performance and construction requirement, in cutter hub (7) the inner surface center of central hob, bush(ing) bearing (5) is installed respectively, one end respectively symmetrical installed thrust cylinder roller bearing (3) of bush(ing) bearing (5) by end cap (4); First carry out the determination of bush(ing) bearing (5) and cylindrical roller thrust bearing (3) type selecting, design and lubricating system, and then complete the design of center bigeminy hobboing cutter dependency structure, specific design method is as follows:

1) central hob is arranged on cutter head center position, bush(ing) bearing (5), and lubricating system is grease lubrication; According to the ultimate load that size and the hobboing cutter of cutter shaft (1), cutter hub (7) bear, and P, V and PV value of bush(ing) bearing is checked, the linear velocity of P to be the average pressure of bearing: V be axle journal: PV is the PV value of bearing; Determine the axle journal D of sliding bearing and the width B of bearing holder (housing, cover), finally determine the model of bush(ing) bearing (5), physical dimension and installation dimension;

2) after determining bush(ing) bearing (5) structure, again according to the physical dimension of cutter hub and cutter shaft, obtain the width of cylindrical roller thrust bearing (3) and the diameter of inner ring, simultaneously according to the limit axial load of hobboing cutter, thus determine the model of cylindrical roller thrust bearing (3); The lubricating system of cylindrical roller thrust bearing (3) is grease lubrication;

3) after the model of bush(ing) bearing (5) and cylindrical roller thrust bearing (3), lubricating system, physical dimension and installation dimension obtain determining, and then the design of cutter hub (7), cutter shaft (1), cutter ring (8), snap ring (6), end cap (4), shaft end ring (2), O RunddichtringO (11) and metal floating ring (12) associated structural component is completed.

2. a kind of development machine center according to claim 1 bigeminy hobboing cutter method for designing, it is characterized in that, the center bigeminy hobboing cutter that this method for designing adopts is made up of cutter shaft (1), shaft end ring (2), cylindrical roller thrust bearing (3), end cap (4), bush(ing) bearing (5), snap ring (6), cutter hub (7), cutter ring (8), two-sided end cap (9), ladder-shaped sealing ring (10), O RunddichtringO (11) and metal floating ring (12); Described cutter ring (8) hot charging on cutter hub (7) outer ring, and is buckled in the outer ring annular groove inner position of cutter hub (7) by snap ring; Bush(ing) bearing (5) is in the center of cutter hub (7), and the solid box of bush(ing) bearing (5) is embedded in cutter hub (7) inner surface center; Two cover thrust roller bearing (3) symmetries are arranged on the both sides of bush(ing) bearing (5), the dynamic lasso of thrust roller bearing (3) and cutter hub (7) interference fit, thrust roller bearing (3) determine lasso and cutter shaft (1) interference fit, and cutter shaft (1) two ends have end cap (4) to locate; At cutter shaft (1) the upper axle head without shaft shoulder location, shaft end ring (2) is set; Ladder-shaped sealing ring (10) is installed in end cap (4) and cutter hub (7) junction; Symmetrical mounting O-shaped sealing ring (11) and metal floating ring (12) in the space that cutter hub (7), cylindrical roller thrust bearing (3) and end cap (4) are formed.