Rock bit installation method

FIELD: construction.

SUBSTANCE: invention pertains to drilling technology, and particularly to the method of installing a rock bit. The method involves the following stages: the legs and rock roller bits are numbered, diameter and linear dimensions of bearing pathways are measured, recorded into a computer and using a special computer program, the "leg-rock roller bit" pairs are selected for each section and drilling bit section. The sections are gathered and welded together. For each drilling bit section, the optimum difference in radial and axial gaps are individually calculated based on the criterion of minimum maximum contact pressure in the support. The "leg-rock roller bit" pairs and drilling bit sections which have minimum deviation of these parameters from corresponding optimum values are then chosen.

EFFECT: increased durability of the support of the drill bit, its increased penetration due to equal distribution of contact loads on the support components.

11 dwg

The invention relates to the drilling technique, namely, drill bits.

There is a method of Assembly of roller bits with a random selection of the legs and bits and layout of the bits of the sections [1].

The disadvantage of this method is that the size of the legs and cones are selected randomly within the field of tolerance. This leads to significant differences in the values of the clearances in the radial and thrust bearings of the supports. When the bit contacts with the bottom is non-simultaneous entry into contact of the respective working surfaces of the bearings. In this part of the bearings immediately kicks in, and the other part starts to work only after the first wear on the difference of the gaps. This leads to overloading of the first significant increase in the specific loads and premature bearing failure. In addition, a random arrangement of bits of the sections with different clearances in the bearings leads to significant differences in the sections of one of the bit Assembly quality, limits the resource bit worst of the selected partitions.

There is a method of assembling bits [2], wherein prior to Assembly of a roller bit comprising an Assembly of individual sections of the legs and cones and the connection sections between the welding, clutches and cone of each type are numbered in the supports of the legs and cones measure diametral dimensions, put the x in the computer and using a specially designed program picked first for each type and number of cones, used in the bit, the leg with the smallest difference between radial and linear gap ΔR and ΔN, then for each bit selects the partition with minor differences on ΔR and ΔN.

The disadvantage of this method is that when the Assembly is not taken into account structural differences (shape and size) large and small bearings that do not provide a completely uniform distribution of the contact stress in the support of each section. In addition, it does not consider differences in the magnitude and direction of the total loads on different partitions of bits.

The aim of the present invention is to increase the resistance of the bit bearing, increase its penetration by reducing the maximum contact stress on the basis of ensuring the most uniform distribution of loads on the bearings within bearing separate sections, and all sections of the bit.

The above objective is achieved by the fact that prior to Assembly of a roller bit comprising the numbering of the legs and cones, measurements in support of the legs and cones diametrically and the linear dimensions of the bearing tracks: D - diameter of the large bearing feet, d is the diameter of the small bearing paws, D_Wthe large diameter of the bearing cone, d_Wthe small diameter of the bearing cone, H is the distance from the axis of the ball track legs to thrust abutment, h is the distance from the axis of the ball track to the KJV the aqueous collar, H_W- the distance from the axis of the ball track to the thrust bearing, h_W- the distance from the axis of the ball track to the thrust collar, the recording of the measured data into the computer, and using a specially designed program pair "paw-roller cutter" for each partition, and partitions for a bit, gather a section of the leg and the cone and weld them together, for each i-section bits calculated using a computer program for optimal difference between radial and linear gap ΔR_ioptand ΔN_ioptdetermined from the condition of minimum of the difference of the contact pressure in the radial and thrust bearings axle Δp_Ri→min and the minimum absolute value of the difference of the contact pressure in the thrust collar and thrust the heel trunnion Δp_Hi→min, then for each bit selects the partition with minor differences of differences of radial clearances ΔR_iand line clearances ΔN_ifrom the respective optimal values collected for each section;

where i is the partition number of the bit;

Δp_Rithe absolute value of the difference of the contact pressure in the large and small radial bearings axle;

Δp_Hithe absolute value of the difference of the contact pressure in the thrust collar and thrust the heel of the neck.

This Assembly procedure of bits allows to solve the problem of increasing the resistance of their supports, etc is checked by the most uniform distribution of the reaction of the bottom hole on the working surfaces of the same name (radial and axial) bearing each of the supports and thus, reducing the maximum specific loads in the zones of contact elements supports. Section bits select settings ΔR and ΔN, are close to the optimal values calculated for each partition that gives the highest possible build quality sections and, as a consequence, the high resistance of their supports and the bit as a whole.

Comparison with the prototype shows that the claimed method differs in that section of bits are selected not from the minimum values ΔR and ΔN, and the optimal defined for each partition individually in accordance with the current load of this section; when linking bits section for one bit are selected with only minor differences on ΔR and ΔN is not among themselves, and from the respective optimal values, providing the highest possible quality of their Assembly. Thus, the inventive method of Assembly of the bits corresponds to the criteria of the invention of "novelty."

Figure 1 shows the pin legs of the bit; figure 2 - scheme of the bearing cones; figa-3E - options contact surfaces of the trunnion and the roller cutter of the i-th section of the bit under the action of reaction slaughter G_iand distribution of contact stress on the elements of the stud.

On the axle 1 (figure 1) are: radial surface high sliding bearing 2 of diameter D, the radial p is the small surface of the sliding bearing 3 with a diameter d, thrust bearing (thrust collar) 4, end bearing (thrust heel) 5 ball and Jogging track 6 of the lock bearing. Sliding surfaces 4 and 5 are respectively at a distance h and H from the axis of the ball treadmill.

On the roller cutter 7 (figure 2) are: radial surface high sliding bearing 8 with a diameter of D_W; radial surface of the small bearing 9 with a diameter of d_W; thrust bearing (thrust collar) 10; end sliding bearing 11; ball Jogging track 12 of the lock bearing. The surfaces 10 and 11 are located from the axis of the ball treadmill, respectively, at a distance of h_Wand H_W.

For each i-th cone (figure 3) in the process operates its own load from the reaction slaughter G_ishared by radial and thrust bearings depending on the values of the difference between the radial clearance

and linear gap

With zero values ΔR and ΔN contact load respectively the radial and axial bearing unevenly distributed on their surfaces because of the structural differences that may not provide optimal contact of the working surfaces of bearings, leads to an overload of one of them and prejdevremennomu fail bit bearing.

If the load G_icontact enter the surface 2 and 8 of the large and the surface 3 and 9 small radial bearings and ΔR_i<ΔR_ioptthen the radial component of the load G_icreates maximum contact pressure p_ilarge sliding bearing (figa); if ΔR_i>ΔR_ioptthen the radial component of the load G_iprovides the highest value of p_iin a small sliding bearing (figb); if ΔR_i=ΔR_ioptthen the radial load is distributed on both radial bearings so that the contact pressure in these bearings is equal to (pigv).

Similarly, if you come in contact surfaces 5 and 11 of the end bearing surfaces 4 and 10 of the thrust collar and ΔN_i<ΔN_ioptthen the axial component of the load G_icreates maximum contact pressure p_iin the end bearing (figh); if ΔN_i>ΔN_ioptthe greatest contact pressure acts on the thrust collar 4 (figd); if ΔN_i=ΔN_ioptthe contact pressure is distributed evenly on the two thrust bearings (fige), which allows to reduce the maximum contact load on the surface 4 and 5 axle, to increase the rigidity of the bearing, to reduce the angle is of Erekose and to increase the resistance of the bearings.

During Assembly of the bits on the proposed methodology must adhere to the conditions:

the difference between the radial clearance

the difference between the linear clearance

The closer the values of the differences clearances ΔR_iand ΔN_ito the respective optimum values, the smaller the maximum value of the contact load p_iin support of the i-th section and, consequently, the higher its resistance. Within one bit of the section are selected with only minor differences differences radial ΔR_iand linear ΔN_iclearances from the respective optimal values.

Build bits for the proposed method is carried out in the following order. Paws and cone of each of N types of numbers. Stubs of legs measure the diameters D, d and linear dimensions H, h (see figure 1), the cones measure the diameters D_Wd_Wdimensions H_Wh_W, put these settings in the computer in a tabular form and, using a specially designed program by the formulas (1) and (2) is calculated for all possible combinations of the clutches and cones difference radial clearances ΔR_iand line clearances ΔN_iand sequentially for each bit selects the sets of cones(№1, №2, ..., №N) and paws, satisfying the condition (3), and at a fixed level ΔR_iand condition (4), PR is than within the bit section of the pick up with minimal differences to differences clearances: Δ R_ifrom ΔR_ioptand ΔN_ifrom ΔN_iopt. According to the results of the calculations of the table is formed, where each room collect the bit numbers of the legs and cones for each of the N sections. When this bit in the table are in ascending order of difference ΔR_ifrom ΔR_ioptand ΔN_ifrom ΔN_iopti.e. in order to reduce the build quality bits. In accordance with the data tables are equipped with a separate section and of sections going drill bits.

For bits with bearings roller bearings difference radial clearances ΔR is calculated by the formula:

where D_pd_p- the diameters of the large and small rollers.

The above-described method was tested during Assembly 20 bits diameter 215,9 mm

Figure 4 presents the graph of the distribution of the average stability of bits in 3 ranges maximum deviation in the bit ΔR_ifrom ΔR_iopt.

The analysis of the diagram implies that the minimum variance (range 0÷0,004 mm) corresponds to the highest average resistance bits - 253 thousand revolutions; the second range of deviations (0,004÷0,008 mm) corresponds to 205 thousand rpm, which is 19% lower compared with the first; the third range (0,008÷0.012 mm) corresponds to the average resistance 159 thousand revolutions that 37.2% lower than for the 1-St dia is Altanbulag. It follows that the main quality indicator bit is its resistance is significantly reduced with the increase of the maximum deviation parameter ΔR_ifrom optimal.

Figure 5 is a diagram of the distribution of the number of bits for the same ranges of the maximum deviation in the bit ΔR_ifrom ΔR_ioptfor the two methods.

From the diagram it follows that in the 1st range is adjudged to be 10 bits (50%)collected on the proposed method, and 8 bits (40%), collected using the basic method (2); in the 2nd range falls respectively 6 bits (30%) and 5 bits (25%); in the 3rd range, respectively 4 bits (20%) and 7 bits (35%). It follows that the build quality bits for parameter ΔR_ifor the described methods is significantly higher than for the basic techniques of selective computer Assembly bits.

Figure 6 shows a diagram of the distribution of the number of bits in 3 ranges maximum deviation in the bit ΔN_ifrom ΔN_iopt.

The analysis of the diagram implies that in the first range (0÷0.001 mm) is adjudged to be 8 bits (40%) in the case of Assembly on the proposed method and 6 bits (30%) for the basic method of Assembly; in the 2nd range (0,001÷0,002 mm) is adjudged to be respectively 7 bits (35%) and 6 bits (30%); in the 3rd range, respectively 5 bits (25%) and 8 bits (40%). Therefore, the build quality bits for parameter ΔN_i using the proposed method are higher than at basic technique of selective computer Assembly bits.

Thus, drill bits collected by the proposed method, in comparison with collected using the basic method of selective computer assemblies have a higher build quality on two composite indicators - the difference radial ΔR_iand linear ΔN_iclearances in the bearings, which ensures a significant increase in resistance supports drill bits and drilled.

The present invention can be used at the enterprises producing drilling roller bit.

Sources of information

1. Sultans YEAR Progressive technology petroleum engineering. - M.: mechanical engineering, 1969, s-132.

2. RF patent №2184203, EV 10/20, 27.06.2002, bull. No. 18.

The method of assembling a roller bit, which consists in the fact that legs and cone numbers, in support of the legs and cones measure the diametrical dimensions of the bearing tracks: D - diameter of the large bearing feet, d is the diameter of the small bearing paws, D_Wthe large diameter of the bearing cone, d_Wthe small diameter of the bearing cone, H is the distance from the axis of the ball track legs to thrust abutment, h is the distance from the axis of the ball track paws to the thrust collar, H_W- the distance from the axis of the ball is the first track of the milling cutter to the thrust bearing, h_W- the distance from the axis of the ball track of the milling cutter to the thrust collar, put them into a computer and using a specially designed computer program pick up a pair of "paw-roller cutter" for each section and for a bit, collecting sections and weld them together, characterized in that for each i-th section of the bit count of the optimal difference between radial and linear gap ΔR_ioptand ΔN_ioptdetermined from the conditions of minimum absolute value of the difference of the calculated contact pressures in the large and small radial bearings axle Δp_Ri→min and the minimum of the absolute value of the difference of the calculated contact pressures in the thrust collar and thrust the heel trunnion Δp_Hi→min, then for each bit selects the partition with minor differences of differences of radial clearances ΔR_iand line clearances ΔH_ifrom the respective optimal values collected for each partition.