CN103352706A - Method for designing center bigeminal hobs of heading machine - Google Patents

Abstract

The invention relates to a design method of a double-connected hob at the center of a roadheader, which belongs to the technical field of tunnel construction machinery and equipment, and relates to a cutter, in particular to a design method for a double-connected hob at the center of a roadheader supported by sliding. This method is based on the overall technical performance and construction requirements of the hob, and under the condition of ensuring that the central double hob has sufficient strength and rigidity, radial sliding bearings are respectively installed at the center of the inner surface of the cutter; Thrust cylindrical roller bearings are installed separately; trapezoidal sealing rings are installed at the joints of the cutter body, end cover and double-sided end cover, and floating seals are installed in the closed space formed by the cutter body, thrust bearing and end cover. The invention adopts the combined form of thrust roller bearing, end cover and shaft end retaining ring in the axial direction to improve the strength, rigidity and stability of the hob; installing two sets of sliding bearings in the radial direction has good impact resistance and vibration absorption, reducing The vibration and damage of the cutter head are reduced, thereby improving the life of the hob and the reliability of the cutter head supporting propulsion system.

Description

A design method for the double hob in the center of the roadheader

Technical field:

The invention belongs to the technical field of tunnel construction machinery and equipment, and relates to a cutting tool, in particular to a design method of a double-connected hob at the center of a roadheader supported by sliding.

Background technique:

As the most important cutting tool for full-face rock boring machines, disc hobs are the most important cutting tools for rocks in mountains and tunnels. Under the harsh working conditions of wear and tear, the cutting tool of the roadheader becomes the most vulnerable part in the tunneling process. The space in the middle of the cutter head is limited, and most of the cutter heads are equipped with central double or multiple hobs. Due to the special position of the central hob, the rotation speed is low but the force is extremely complicated. During the rock breaking process, it is often subject to strong impact and vibration. It leads to cutter body movement, bearing damage and seal failure, which greatly reduces the life of the hob, and the vibration and impact of the hob are transmitted to the cutter head through the cutter shaft, causing vibration and damage to the cutter head, which in turn affects the support of the cutter head , The reliability of propulsion and slewing systems.

In the traditional center multiple hob design, two rows of back-to-back tapered roller bearings are used to support the cutter ring and cutter body. Because this pair of tapered roller bearings can simultaneously bear large radial loads and Axial load, widely used in rock boring machine hob structure. Chinese patent number: 201120558297.5, the patent name is: split narrow center hob, the inventor Bord John Laitner provides a split narrow center hob, including a hob body and an annular tool seat, the hob body A card slot is provided on the outer surface of the outer surface, and a C-shaped collar is clamped and abutted between the annular tool seat and the card slot. Chinese patent number: 201120258547.3, the patent name is: A double-disc central hob for a shield machine. The inventor Li Wei and others provided a double-disc central hob for a shield machine. The hardness of the knife ring reaches HRC55-58. The tensile strength reaches 2000MPa, which is wear-resistant and durable; at the same time, the labor intensity of workers is reduced; the investment is low and the construction application range is wide. The patent written by Burd John Laitner uses the annular knife seat and the C-shaped collar to facilitate the replacement and installation of the hob cutter body, which improves the efficiency; the patent written by Li Wei et al. The sealing of the hob has been greatly improved, but the patent does not take into account the poor impact resistance and vibration absorption effect of the two-row tapered rolling bearings. Vibration, the hob is often scrapped ahead of time due to the failure of the bearing and seal due to excessive vibration, and the excessive vibration of the hob also has certain damage to the cutter head and the cutter head propulsion system. Therefore, the novel center hob of the above invention still has the defects of weak impact resistance and poor vibration absorption effect.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art, and to invent a design method for the double hob at the center of the roadheader with sliding support. This design method enables the center hob to withstand relatively high Strong shock and vibration, which improves the service life of the hob and cutterhead and the reliability of the cutterhead propulsion system.

The technical solution adopted in the present invention is a design method of the central double hob of the roadheader. The method considers the overall technical performance and construction requirements of the central double hob, and installs a diameter at the center of the inner surface of the cutter body 7 of the central hob. To the sliding bearing 5, the thrust cylindrical roller bearing 3 is symmetrically installed on the end of the radial sliding bearing 5 close to the end cover 4; firstly, the selection, design and lubrication method of the radial sliding bearing 5 and the thrust cylindrical roller bearing 3 are determined , and then complete the design of the relevant structure of the central double hob, the specific design method is as follows:

1) The center hob is installed at the center of the cutter head. The maximum speed of the hard rock roadheader cutter head is about 8r/min, and the maximum speed of the hob installed at the center of the cutter head is about 26r/min. The maximum radial load borne by the center hob can reach more than 200KN, so the rock breaking process of the center hob belongs to the low-speed and heavy-load working condition; the relative speed between the inner ring of the hob cutter and the journal of the cutter shaft is low (about 0.15m/s), And it works intermittently, it is difficult to form a continuous dynamic pressure oil film, so it is not suitable for sliding bearings with complete liquid lubrication; the working condition of the center hob is bad, it is difficult to supply oil frequently, and it is inconvenient to add lubricant, so the sliding support part of the center hob is Incomplete liquid lubricated radial sliding bearing 5, the lubrication method is grease lubrication; check the P, v and PV values of the radial sliding bearing according to the size of the cutter shaft 1, cutter body 7 and the limit load borne by the hob , determine the journal D of the sliding bearing and the width B of the bearing sleeve, so as to finally determine the type, structural size and installation size of the radial sliding bearing 5;

2) After determining the structure of the radial sliding bearing 5, the width of the thrust cylindrical roller bearing 3 and the diameter of the inner ring are obtained according to the structural dimensions of the cutter body and the cutter shaft, and the thrust is determined according to the ultimate axial load of the hob Model of cylindrical roller bearing 3;

Choice of lubrication method for thrust cylindrical roller bearings 3: the lubricating film of grease has high strength, can withstand large loads, is not easy to lose, is easy to seal, and is only suitable for lower dn values (not for thrust roller bearings) greater than 40000mm·r/min); while the speed of the central double hob is low (about 2600mm·r/min), and the lubrication method of the sliding bearing is grease lubrication, so the lubrication method of the thrust cylindrical roller bearing 3 is selected as grease lubricating;

3) After the type, lubrication method, structural size and installation size of the radial sliding bearing 5 and the thrust cylindrical roller bearing 3 are determined, the cutter body 7, cutter shaft 1, cutter ring 8, snap ring 6, and end cover 4 are completed. , shaft end retaining ring 2, O-ring 11 and metal floating ring 12 and other related structural parts design;

The design method of a double-joint hob at the center of a roadheader is characterized in that the double-joint center hob used in the design method consists of a cutter shaft 1, a shaft end retaining ring 2, a thrust cylindrical roller bearing 3, and an end cover 4 , radial sliding bearing 5, snap ring 6, cutter body 7, cutter ring 8, double-sided end cover 9, trapezoidal sealing ring 10, O-shaped sealing ring 11 and metal floating ring 12; On the outer ring of the cutter body 7, it is positioned in the annular groove of the outer ring of the cutter body 7 through a snap ring; the radial sliding bearing 5 is at the center of the cutter body 7, and the integral sleeve of the radial sliding bearing 5 is embedded in the cutter body 8 The center position of the inner surface; two sets of thrust roller bearings 3 are symmetrically installed on both sides of the radial sliding bearing 6, the moving ring of the thrust roller bearing 3 and the cutter body 7 are interference fit, and the fixed sleeve of the thrust roller Ring and the cutter shaft 1 interference fit, and the two ends of the cutter shaft 1 are positioned by the end cap 4; the shaft end of the cutter shaft 1 without shoulder positioning is provided with a shaft end retaining ring 2; the end cover 2 and the cutter body 7 are installed at the joint A trapezoidal sealing ring 10 ; an O-ring sealing ring 11 and a metal floating ring 12 are installed symmetrically in the space formed by the cutter body 7 , the thrust cylindrical roller bearing 3 and the end cover 4 .

The beneficial effects of the present invention are: the structure of the central double hob cutter body 7 is simple, and the manufacturing and assembly are relatively convenient; a trapezoidal rubber ring 10 is installed at the joint between the end cover 4 and the cutter body 7, which greatly improves the overall sealing of the hob The combination of two sets of thrust cylindrical roller bearings 3, axial retaining ring 2 and end cover 4 at both ends of the cutter shaft 1 improves the tool's ability to resist axial loads and reduces axial displacement and vibration; two sets of radial sliding bearings 5 has a certain vibration absorption capacity, which greatly reduces the impact and vibration of the cutter shaft 1, thereby reducing the vibration and damage of the cutter head, and improving the reliability of the center hob and cutter head support propulsion system. The hob axial stiffness and vibration absorption capacity are improved, the vibration of the hob and cutterhead is reduced, and the life of the hob and the reliability of the cutterhead supporting propulsion system are improved.

Description of drawings

Fig. 1 is a schematic diagram of the overall structure of the hob of the present invention. In the figure: 1. Cutter shaft; 2. Shaft end retaining ring; 3. Thrust cylindrical roller bearing; 4. End cover; 5. Radial sliding bearing; 6. Snap ring; 7. Cutter body; 8. Cutter ring; 9. Double-sided end cover; 10. Trapezoidal sealing ring; 11. O-shaped sealing ring; 12. Metal floating ring.

specific embodiment

The specific implementation of the present invention will be described in detail in conjunction with the accompanying drawings and technical solutions. During the working process of the full-face rock boring machine, the center hob is subjected to radial, axial and moment impact loads, wherein the radial load is the direction of the maximum load on the hob, and the vibration of the hob is caused under this combined impact load, thereby It leads to seal failure and bearing damage, which greatly reduces the life of the hob; at the same time, the hob cutter shaft is fixed on the cutter head, and the impact and vibration on the cutter shaft are directly transmitted to the cutter head, causing damage to the cutter head and the support of the cutter head, Reliability of propulsion and slewing systems. In order to reduce the vibration of the center hob and the cutter head, it is necessary to try to reduce the impact and vibration of the center hob in the radial direction, and at the same time increase the axial and overturning stiffness of the hob. At present, the slewing support structure of the most commonly used center hob adopts two rows of tapered roller bearings installed back to back, but the impact resistance of tapered roller bearings is weaker, and the axial stiffness is smaller than that of cylindrical roller bearings.

At present, the maximum rotational speed of the cutter head of the hard rock roadheader is about 8r/min, and the maximum rotational speed of the hob installed in the center of the cutter head is about 26r/min, and the maximum radial load borne by the hob during rock breaking can reach Above 200kN, the rock-breaking process of the center hob belongs to the low-speed and heavy-load working condition; the relative speed between the inner ring of the hob cutter and the journal of the cutter shaft is low (about 0.15m/s), and it works intermittently, so it is difficult to form a continuous dynamic The oil film is pressed, so it is not suitable for completely liquid-lubricated sliding bearings; the working condition of the center hob is harsh, it is difficult to supply oil frequently, and it is inconvenient to add lubricant, so the sliding support parts of the center hob are incompletely liquid-lubricated. For the choice of lubrication method for thrust cylindrical roller bearings (3): the lubricating film of grease has high strength, can withstand large loads, is not easy to lose, is easy to seal, and is only suitable for lower dn values; The rotation speed of the hob is low, and the lubrication method of the sliding bearing is grease lubrication, so the lubrication method of the thrust cylindrical roller bearing (3) is selected as grease lubrication.

The present invention aims at the defects of relatively weak impact resistance and poor vibration absorption effect in the current center hob, and respectively installs radial sliding bearings at the center of the inner surface of the cutter; and symmetrically installs two sets of thrust cylindrical roller bearings on both sides of the radial sliding bearings , The moving ring of the thrust bearing has an interference fit with the cutter body, and the fixed ring has an interference fit with the cutter shaft. The specific structural diagram is shown in Figure 1. The invention adopts the combined form of two sets of sliding bearings and two sets of thrust bearings to improve the strength, rigidity and stability of the hob; the sliding bearings installed in the radial direction of the hob have good impact resistance and vibration absorption, and reduce the cost of the cutter shaft and the cutter head. vibration and damage; thereby improving the life of the hob and the reliability of the propulsion system supported by the cutter head. The present invention is equally applicable to the central two-joint, quadruple-joint, eight-joint hobs and super-digging cutters. The design method of the center hob of the present invention will be described in detail below by taking the 17-inch center double-joint hob as an example:

1) Selection and design of radial sliding bearings

In order to make the designed hob economical and applicable, sliding bearings and hob bearings should be selected as standard parts as much as possible, and for low-speed and heavy-duty bearings, a larger value should be selected to improve the overall rigidity of the bearing. Combined with the current 17-inch center hob cutter shaft and the overall structural size of the hob, the initial cutter shaft journal is 120mm, and the sliding bearing width is 100mm.

The speed of the cutter head is set to n _{cutter head} =8r/min, and the diameter of the hob d=0.432m; the linear speed of the hob at the contact point of the hob and the cutter head is equal, and the linear speed of the hob is calculated at this point, which is farthest from the center of the cutter head The pole diameter of the central hob is about 0.705m, and the speed n=21.6r/min of the hob is obtained;

The peripheral speed of the journal is:

$\mathrm{<span\; class="notranslate">\; \&upsi;</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&pi;dn</span>}}{\mathrm{<span\; class="notranslate">\; 60</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 1000</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 120</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 26.1</span>}}{\mathrm{<span\; class="notranslate">\; 60</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 1000</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0.164</span>}\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}$

The relative clearance of the bearing is:

$\mathrm{<span\; class="notranslate">\; \&psi;</span>}<span\; class="notranslate">\; =</span>\frac{{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 60</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 9</span>}}}{{\mathrm{<span\; class="notranslate">\; 10</span>}}^{\mathrm{<span\; class="notranslate">\; 31</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 9</span>}}}<span\; class="notranslate">\; =</span>\frac{{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 21.6</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 60</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 9</span>}}}{{\mathrm{<span\; class="notranslate">\; 10</span>}}^{\mathrm{<span\; class="notranslate">\; 31</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 9</span>}}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2.28</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; 10</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 4</span>}}\mathrm{<span\; class="notranslate">\; mm</span>}$

Initially estimate the dynamic viscosity of the oil:

$\mathrm{<span\; class="notranslate">\; \&eta;</span>}<span\; class="notranslate">\; =</span>\frac{{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 60</span>}<span\; class="notranslate">\; )</span>}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 3</span>}}}{{\mathrm{<span\; class="notranslate">\; 10</span>}}^{\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 6</span>}}}<span\; class="notranslate">\; =</span>\frac{{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 26.1</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 60</span>}<span\; class="notranslate">\; )</span>}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 3</span>}}}{{\mathrm{<span\; class="notranslate">\; 10</span>}}^{\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 6</span>}}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0.09</span>}\mathrm{<span\; class="notranslate">\; Pa</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}$

Therefore, the bearing factor can be obtained:

${\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; F\&psi;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; \&eta;\&omega;dB</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; F\&psi;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&eta;\&upsi;B</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 200000</span>}<span\; class="notranslate">\; \&times;</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2.28</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; 10</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 0.09</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 0.164</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 0.1</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 3.522</span>}$

Check the load capacity coefficient table of the finite width bearing, and obtain the eccentricity of the sliding bearing by interpolation:

χ=0.825

Calculate the minimum oil film thickness:

${\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; min</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; d</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; \&psi;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&chi;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 120</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 2.28</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; 10</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 0.825</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2.39</span>}\mathrm{<span\; class="notranslate">\; um</span>}$

Determine the ten-point height of the surface roughness of the journal and bearing hole. According to the processing accuracy requirements, the surface roughness level of the journal is 0.8, and the surface roughness level of the bearing hole is 1.6. Look up the table and get:

Journal R _z1 =3.2um

Bearing hole R _z1 =6.3um

The safety factor S should be greater than or equal to 2, and the allowable oil film thickness is calculated as,

[h]=S(R _Z1 +R _Z2 )=2×(3.2+6.3)=19um

It can be obtained from the above:

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

In order to ensure that the minimum oil film thickness h _min is sufficient to submerge the microscopic unevenness of the two surfaces of the journal and the bearing, and to realize truly complete fluid friction, when the safety factor is taken as 2, the calculated minimum oil film thickness should be greater than the allowable oil film thickness. However, h _min <[h] is obtained from the above calculation results, so it cannot meet the work reliability requirements, so it is not possible to use fully hydrodynamic sliding bearings. However, because the working condition of the hob is low speed, heavy load, and intermittent work, incomplete liquid lubrication is selected. At the same time, considering that the working condition of the hob is complicated and it is inconvenient to add lubricant frequently, grease lubrication is used.

Calculated according to the maximum rated thrust of 17-inch center hob 200kN as the external limit load:

The average pressure P of the bearing:

$\mathrm{<span\; class="notranslate">\; p</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; f</span>}}{\mathrm{<span\; class="notranslate">\; dB</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 200000</span>}}{\mathrm{<span\; class="notranslate">\; 120</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 100</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 16.7</span>}\mathrm{<span\; class="notranslate">\; MPa</span>}$

The linear velocity V of the journal:

$\mathrm{<span\; class="notranslate">\; v</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&pi;dn</span>}}{\mathrm{<span\; class="notranslate">\; 60</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 1000</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 120</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 26.1</span>}}{\mathrm{<span\; class="notranslate">\; 60</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 1000</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0.164</span>}\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}$

Check the PV of the bearing:

$\mathrm{<span\; class="notranslate">\; PV</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; f</span>}}{\mathrm{<span\; class="notranslate">\; dB</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\frac{\mathrm{<span\; class="notranslate">\; \&pi;dn</span>}}{\mathrm{<span\; class="notranslate">\; 60</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 1000</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; fn</span>}}{\mathrm{<span\; class="notranslate">\; 19100</span>}\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 200000</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 26.1</span>}}{\mathrm{<span\; class="notranslate">\; 19100</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 100</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2.733</span>}\mathrm{<span\; class="notranslate">\; MPa</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}$

From the above calculation and analysis, it can be obtained: P>15MPa, v<1m/s, which belong to low-speed and heavy-load conditions, and lead bronze ZCuPB30 is suitable for heavy-duty bearings, and can withstand variable load impacts. The maximum allowable values are 25MPa, respectively. 12m/s, 30MPa m/s, so it can meet the above design requirements.

2) Selection and design of thrust bearings

After the type and lubrication method of the sliding bearing are determined, the thrust cylindrical roller bearing can be selected according to the size of the journal of the cutter shaft and the cutter body. According to the cutter shaft diameter of 120mm, the maximum axial load of the hob is about 30KN, so the model of the thrust rolling bearing is 81124, and the basic rated dynamic load is 155KN, which meets the design requirements and has sufficient axial stiffness. It is more complicated and inconvenient to add lubricant frequently, and the sliding bearing is lubricated with grease, so the rolling bearing also adopts the sliding bearing lubrication method.

3) Design of hob-related structures

After the structural size, lubrication method and installation size of the radial sliding bearing and thrust cylindrical roller bearing are determined, the design of the cutter body, cutter shaft, end cover and shaft end retaining ring is completed, and finally the cutter body, end cover and thrust cylindrical roller bearing are designed. A floating sealing device is designed for the closed space formed by the sub-bearings, and the specific structural layout is shown in Figure 1.

Through the above design, it can be concluded that the center double hob of a sliding support roadheader of the present invention has the following advantages: the structure of the center double hob cutter body is simple, and the manufacturing and assembly are relatively convenient; The trapezoidal rubber ring is installed at the center of the hob, which greatly improves the overall sealing performance of the hob; the combination of the thrust cylindrical roller bearing, the end cover and the shaft end retaining ring increases the overall axial stiffness of the hob, thereby improving the axial load resistance of the hob. The ability to reduce the axial displacement and vibration of the hob, thereby improving the service life of the center hob; the radial sliding bearing installed on the inner surface of the cutter has a certain vibration absorption capacity, which greatly reduces the vibration of the cutter shaft, and then The vibration and damage of the cutter head are reduced, and the reliability of the cutter head supporting propulsion system is improved.

Claims (2)

1. A design method for the central two-unit hob of a roadheader, characterized in that the method is based on the overall technical performance and construction requirements of the central two-unit hob, respectively installing diameters at the center of the inner surface of the cutter body (7) of the central hob To the sliding bearing (5), install the thrust cylindrical roller bearing (3) symmetrically on the end of the radial sliding bearing (5) close to the end cover (4); first, install the radial sliding bearing (5) and the thrust cylindrical roller bearing (3) Determine the type selection, design and lubrication method, and then complete the design of the relevant structure of the central double hob. The specific design method is as follows: 1) The center hob is installed at the center of the cutter head, the radial sliding bearing (5) is lubricated with grease; according to the size of the cutter shaft (1), cutter body (7) and the ultimate load borne by the hob, and Check the P, v and PV values of the radial sliding bearing, determine the journal D of the sliding bearing and the width B of the bearing sleeve, and finally determine the type, structure size and installation size of the radial sliding bearing (5); 2) After determining the structure of the radial sliding bearing (5), the width of the thrust cylindrical roller bearing (3) and the diameter of the inner ring are obtained according to the structural dimensions of the cutter body and the cutter shaft, and at the same time according to the ultimate axial load of the hob , so as to determine the model of the thrust cylindrical roller bearing (3); the lubrication method of the thrust cylindrical roller bearing (3) is grease lubrication; 3) After the type, lubrication method, structural size and installation size of the radial sliding bearing (5) and thrust cylindrical roller bearing (3) are determined, the cutter body (7), cutter shaft (1), cutter ring ( 8), design of snap ring (6), end cover (4), shaft end retaining ring (2), O-ring (11) and metal floating ring (12). 2. A method for designing a central two-unit hob of a roadheader according to claim 1, characterized in that the central two-unit hob used in the design method consists of a cutter shaft (1), a shaft end retaining ring (2), Thrust cylindrical roller bearing (3), end cover (4), radial sliding bearing (5), snap ring (6), cutter body (7), cutter ring (8), double-sided end cover (9), trapezoid The sealing ring (10), the O-ring (11) and the metal floating ring (12); the knife ring (8) is heat-fitted on the outer ring of the knife body (7), and is fastened to the knife body ( 7) is positioned in the annular groove of the outer ring; the radial sliding bearing (5) is at the center of the cutter body (7), and the integral sleeve of the radial sliding bearing (5) is embedded in the center of the inner surface of the cutter body (8); Two sets of thrust roller bearings (3) are symmetrically installed on both sides of the radial sliding bearing (6). ) and the cutter shaft (1) are interference fit, and the two ends of the cutter shaft (1) are positioned by end caps (4); on the shaft end of the cutter shaft (1) where there is no shaft shoulder to locate, a shaft end retaining ring is set (2); trapezoidal sealing ring (10) is installed at the connection between end cover (2) and cutter body (7); the space formed by cutter body (7), thrust cylindrical roller bearing (3) and end cover (4) is symmetrical Install O-ring seal (11) and metal floating ring (12).

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