CN103352706A - 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 the tunnel construction machinery equipment technical field, 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, because the complexity of high strength, high rigidity and the geological conditions of massif, tunnel rock and boring machine cutter are operated under the bad working environments of strong extruding, high pulling torque, thump, high wearing and tearing, make boring machine cutter become the most flimsy component in the tunneling process.The cutterhead central space is limited, most of cutterheads centre mounting center bigeminy or multi-joint hobboing cutter, because the central hob position is special, rotating speed is lower but stressed very complicated, often is subject to powerful shock and vibration in rock break-off process, causes cutter hub play, damage of bearings and seal failure, greatly reduce the life-span of hobboing cutter, and the vibration that hobboing cutter bears and impact are delivered to cutterhead by cutter shaft, cause vibration and the damage of cutterhead, and then affect the reliability of support, propelling and the rotary system of cutterhead.

In the multi-joint hobboing cutter design in traditional center, what cutter ring and cutter hub were played the revolution supporting role is the taper roll bearing of the back-to-back installation of two row, because this a pair of taper roll bearing can bear very large radial load and axial load simultaneously, is widely used in the 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 provides a kind of split narrow central hob, comprise hobboing cutter body and annular tool rest, the lateral surface of described hobboing cutter body is provided with draw-in groove, and the clamping butt has C shape collar between described annular tool rest and the 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, and is wear-resisting, durable; Reduced simultaneously workman's labour intensity; Invest lowly, construction application is in extensive range.Vigorous De Yuehanlai rise receive the patent of writing make things convenient for the operations such as replacing, installation of hobboing cutter cutter hub by annular tool rest and C shape collar, improved efficient; The patents that the people writes such as Li Wei are greatly improved to the abrasion resistance of cutter ring and the sealing of hobboing cutter, but the shock resistance and the shock attenuation result that reckon without two row cone rollings in the patent are poor, the operating mode of rock ripper is more abominable again simultaneously, the powerful shock and vibration that hobboing cutter usually will bear, hobboing cutter often excessively causes bearing and seal failure to be scrapped in advance because vibrating, and the hobboing cutter vibration is excessive that cutterhead and cutterhead propulsion system are also had certain damage.So still there is the weak and poor defective of shock attenuation result of impact resistance in the novel central hob of foregoing invention.

Summary of the invention

The technical barrier that the present invention will solve is to overcome 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 be can bear, hobboing cutter, the application life of cutterhead and the reliability of cutterhead propulsion system improved.

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 is considered center bigeminy hobboing cutter overall technology performance and construction requirement, in the cutter hub 7 inner surface centers of central hob bush(ing) bearing 5 is installed respectively, at the end difference symmetrical installed thrust cylinder roller bearing 3 of bush(ing) bearing 5 by end cap 4; At first carry out determining of bush(ing) bearing 5 and cylindrical roller thrust bearing 3 type selectings, design and lubricating system, and then finish the design of center bigeminy hobboing cutter dependency structure, the specific design method is as follows:

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

2) determine bush(ing) bearing 5 structures after, 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, thereby 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, is difficult for running off, and easily sealing, and be only applicable to lower dn value (being not more than 40000mmr/min for thrust roller bearing); And center bigeminy hobboing cutter rotating speed lower (approximately 2600mmr/min), and the lubricating system of sliding bearing is grease lubrication, so the lubricating system of selected cylindrical roller thrust bearing 3 is grease lubrication;

3) after model, lubricating system, physical dimension and the installation dimension of bush(ing) bearing 5 and cylindrical roller thrust bearing 3 obtain determining, and then finish the design of the dependency structure spares 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;

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 comprised 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 chargings and are buckled in the outer ring annular groove of cutter hub 7 position decided at the higher level but not officially announced by snap ring on cutter hub 7 outer rings; 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 centers; Two cover thrust roller bearings 3 symmetries are installed in the both sides of bush(ing) bearing 6, the moving lasso of thrust roller bearing 3 and cutter hub 7 interference fit, thrust roller bearing 3 decide lasso and cutter shaft 1 interference fit, and cutter shaft 1 two ends have end cap 4 to locate; Axle head without shaft shoulder location on cutter shaft 1 arranges shaft end ring 2; Ladder-shaped sealing ring 10 is installed in end cap 2 and cutter hub 7 junctions; 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 form.

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

Description of drawings

Fig. 1 is hobboing cutter overall structure schematic diagram of the present invention.Among the 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

Describe implementation of the present invention in detail with technical scheme by reference to the accompanying drawings.Full face rock tunnel boring machine in the course of the work, central hob is subject to radially, axially and under the moment shock loading, wherein radial load is that hobboing cutter bears the peak load direction, under this associating shock loading, cause the vibration of hobboing cutter, thereby cause seal failure, damage of bearings, reduced greatly the life-span of hobboing cutter; The hobboing cutter cutter shaft is fixed on the cutterhead simultaneously, and the shock and vibration that cutter shaft is subject to are directly delivered to cutterhead, cause the damage of cutterhead and the reliability of cutter head support, propelling and rotary system.In order to reduce the vibration of central hob and cutterhead, must manage to reduce the shock and vibration of central hob radial direction, increase simultaneously cutter shaft to the rigidity of toppling.Two row tapered roller bearings of back-to-back installation and at present the rotation supporting structure of the most frequently used central hob adopts, and the impact resistance of taper roll bearing a little less than, and axial rigidity is less than cylinder roller bearing.

At present, hard rock mole cutterhead maximum (top) speed is approximately 8r/min, the maximum (top) speed that then is installed in the hobboing cutter at cutterhead center is approximately 26r/min, and the maximum radial load of bearing in the hobboing cutter rock break-off process can reach more than the 200kN, so the central hob rock break-off process belongs to the low-speed heave-load operating mode; The relative rotation speed of hobboing cutter cutter hub inner ring and cutter shaft axle journal lower (about 0.15m/s), and intermittent work are difficult to form continuous dynamic pressure oil film, so be not suitable for the lubricated sliding bearing of fully liquid; The central hob operating mode is abominable, is difficult to frequent fuel feeding, and inconvenience interpolation sliding agent, so 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, is difficult for running off, and easily sealing, 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, so the lubricating system of selected cylindrical roller thrust bearing (3) is grease lubrication.

The present invention is directed to present central hob and still have the weak and poor defective of shock attenuation result of impact resistance, bush(ing) bearing is installed in cutter hub inner surface center respectively; The symmetrical two cover cylindrical roller thrust bearings of installing on the both sides of bush(ing) bearing, the moving-coil of thrust bearing and cutter hub interference fit, fixed circle and cutter shaft interference fit, the concrete structure schematic diagram is as shown in Figure 1.The present invention adopts two cover sliding bearings and two cover thrust bearing combination forms to improve intensity, rigidity and the stability of hobboing cutter; The sliding bearing that hobboing cutter is radially installed has good shock resistance and absorbing, has reduced vibration and the damage of cutter shaft and cutterhead; Thereby the life-span of hobboing cutter and the reliability of cutter head support propulsion system have been improved.The present invention is equally applicable to center bigeminy, tetrad, eight hobboing cutters and the cutter of backbreaking, and the below specifies the method for designing of central hob of the present invention as example take 17 cun center bigeminy hobboing cutters:

1) Selection and Design of bush(ing) bearing

Economic and practical for the hobboing cutter that makes design, sliding bearing and the cutter bearing choice criteria part of trying one's best, and low-speed heave-load bearing for improving the bearing integral rigidity, should be got higher value.In conjunction with the physical dimension that 17 cun central hob cutter shafts and hobboing cutter integral body are arranged now, first stationary knife shaft neck is 120mm, and plain journal bearing width is 100mm.

The cutterhead rotating speed is made as n _Cutterhead=8r/min, cutter diameter d=0.432m; Utilize the linear velocity of hobboing cutter and cutterhead contact point to equate, calculate the linear velocity of this place's hobboing cutter, directly be approximately 0.705m apart from the utmost point of cutterhead center central hob farthest, try to achieve the rotation 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:

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

So can get bearing capacity factor:

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

Looking into has the bearing capacity factor of limit for width bearing table, obtains the 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, 10 height of dead eye surface roughness, going the journal surface roughness grade number by requirement on machining accuracy is 0.8, and dead eye rough surface grade is 1.6, tables look-up and can get:

Axle journal R _Z1=3.2um

Dead eye R _Z1=6.3um

Getting safety factor S should be more than or equal to 2, calculate oil film thickness allowable to be,

[h]=S(R _Z1+R _Z2)=2×(3.2+6.3)=19um

By on can get:

h _min(2.39um)<[h](19um)

In order to guarantee minimum oil film thickness h _MinBe enough to flood the nao-and micro relief on axle journal and bearing two surfaces, realize really completely fluid friction, when safety factor was taken as 2, calculating minimum oil film should be greater than oil film thickness allowable.But get h by above result of calculation _Min＜[h], thus can't satisfy the functional reliability requirement, so can not use complete Hydrodynamic Sliding Bearing.And because the working condition of hobboing cutter is low-speed heave-load, intermittent work so select incomplete hydrodynamic lubrication, considers that simultaneously sliding agent is often added in the operating mode more complicated inconvenience of hobboing cutter, so adopt grease lubrication.

Maximum rated thrust 200kN according to 17 cun central hobs calculates as outer limits load:

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

2) Selection and Design of thrust bearing

After the model of sliding bearing and lubricating system are determined, can be according to the axle journal of cutter shaft and the size Selection cylindrical roller thrust bearing of cutter hub.Be 120mm according to the cutter shaft diameter, the hobboing cutter maximum axial is approximately 30KN, so selecting the model of thrust bearing is 81124, basic dynamic load rating is 155KN, meet design requirement, and sufficient axial rigidity is arranged, sliding agent is often added in the operating mode more complicated inconvenience of hobboing cutter, and what sliding bearing adopted is grease lubrication, so rolling bearing also adopts the 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 finish cutter hub, cutter shaft, end cap and shaft end ring design, the enclosure space design floating seal that consists of at cutter hub, end cap and cylindrical roller thrust bearing at last, concrete structure is arranged as shown in Figure 1.

By above design, the development machine center bigeminy hobboing cutter that can draw a kind of sliding support of the present invention has the following advantages: center bigeminy hobboing cutter structure of the cutter body is simple, and processing and manufacturing and assembling are more convenient; At end cap and cutter hub cooperation place trapezoidal rubber ring is installed, has greatly been improved the sealing of hobboing cutter integral body; Cylindrical roller thrust bearing, end cap and shaft end ring combination have increased the whole axial rigidity of hobboing cutter, thereby have improved the ability of cutter axial load resistant, reduce axial displacement and the vibration of hobboing cutter, thereby have improved central hob application life; The bush(ing) bearing that the cutter hub inner surface is installed has certain vibration absorption ability, has reduced to a great extent the vibration of cutter shaft, and then has reduced vibration and the damage of cutterhead, has improved the reliability of cutter head support propulsion system.

Claims (2)

1. 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, at the end difference symmetrical installed thrust cylinder roller bearing (3) of bush(ing) bearing (5) by end cap (4); At first carry out determining of bush(ing) bearing (5) and cylindrical roller thrust bearing (3) type selecting, design and lubricating system, and then finish the design of center bigeminy hobboing cutter dependency structure, the specific design method is as follows:

1) central hob is installed in the cutterhead center, and bush(ing) bearing (5), lubricating system are grease lubrication; According to the size of cutter shaft (1), cutter hub (7) and the ultimate load that hobboing cutter bears, and to radially P, v and the PV value of sliding bearing are checked, determine the axle journal D of sliding bearing and the width B of bearing holder (housing, cover), finally determine model, physical dimension and the installation dimension of bush(ing) bearing (5);

2) determine bush(ing) bearing (5) structure after, 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, the while is according to the limit axial load of hobboing cutter, thus the model of definite cylindrical roller thrust bearing (3); The lubricating system of cylindrical roller thrust bearing (3) is grease lubrication;

3) after model, lubricating system, physical dimension and the installation dimension of bush(ing) bearing (5) and cylindrical roller thrust bearing (3) obtain determining, and then finish 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) dependency structure spare.

2. a kind of development machine according to claim 1 center bigeminy hobboing cutter method for designing, it is characterized in that the center bigeminy hobboing cutter that this method for designing adopts is comprised 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 and is buckled in the outer ring annular groove of cutter hub (7) position decided at the higher level but not officially announced by snap ring on cutter hub (7) outer 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 installed in the both sides of bush(ing) bearing (6), the moving lasso of thrust roller bearing (3) and cutter hub (7) interference fit, thrust roller bearing (3) decide lasso and cutter shaft (1) interference fit, and there is end cap (4) location at cutter shaft (1) two ends; At the upper axle head without shaft shoulder location of cutter shaft (1) shaft end ring (2) is set; 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) form.

Images