RU2537409C2 - Tool and method of small-diameter hole calibration of nozzles - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to calibration of small-diameter holes in nozzles. Proposed tool is composed by conducting wire with non-conducting wearproof hard narrow belts applied thereon. OD of the latter decreases in wire length as applied coating depth. Note here that OD of the last belt equals hole OD after calibration while spacing between belts makes no over hole length. In compliance with proposed process, coating is applied on calibrated hole after its galvanic-mechanical processing by aforesaid conducting tool. Said tool is fed in hole filled with working fluid to ensure contact between hole surface and at least two wire belts. Then, reversed polarity DC is fed to displace the tool at force varying with layer depth and restricted by breaking point of conducting tool.

EFFECT: efficient calibration, ruled out short-circuits between tool and hole.

2 cl, 2 dwg

Description

The invention relates to the field of engineering and can be used to align the area of the bore in the supply channels of liquid and gaseous substances in the nozzle openings.

Closest to the claimed invention is a device for electrochemical-mechanical processing of channels [Patent 2251472. A method of electrochemical-mechanical processing of channels and a device for its implementation / Dolgushin VV, Kozlova OV, Smolentsev VP and others // Bulletin No. 13, 2005], in which the calibrating element is made in the form of a mandrel with slots of constant diameter and a front guide of constant size.

The disadvantage of this device is the ability to change the cross section of the hole only by removing the allowance in the hole, which does not allow to reduce the area of the bore in the nozzle holes and to regulate the flow rate of the working medium through the holes during calibration in order to obtain the required flow rate and spray of the working medium.

A known method of refining nozzles [Patent 2162394. Method for refining nozzles / Smolentsev VP, Smolentsev GP, Smolentsev EV and others // Bulletin No. 3, 2001], where the flow rate of the working medium is increased by forming an edge at the outlet of the hole.

The disadvantages of the method include the impossibility of reducing the area of the bore and the flow rate of the working medium through the hole in the nozzle in case of overestimating its area.

Closest to the claimed invention is a method of galvanomechanical restoration of conductive parts [Patent 2224827. Method of galvanic-mechanical restoration of conductive parts / Zhachkin S.Yu., Labuzov VV, Smolentsev VP and others // Bulletin No. 6, 2004], where there is an increase in size by galvanic-mechanical coating, which can reduce the area of the passage of the holes. The disadvantages of the method include the inability to reduce the cross-sectional area of the holes of small diameter used in nozzles, due to the lack of space for placing a tool for machining the coating layers.

The invention is aimed at changing the nozzles of the orifice of the orifice in the direction of decreasing it in order to reduce consumption in the case of calibration of the flow and atomization of nozzles, which extends the technological possibilities of calibration and eliminates the rejection of parts in case of exceeding the tolerance of the cross-sectional dimensions of one or more holes.

This is achieved by the fact that the tool is made in the form of a conductive wire with non-conductive wear-resistant hard narrow belts applied, the outer diameter of which decreases along the length of the wire in proportion to the thickness of the coating, and the outer diameter of the last belt is equal to the outer diameter of the hole after calibration, and the pitch between the belts is no more than half the length of the calibrated hole, while it is configured to provide space between the outer section of the conductive wire and the surface of the hole along the length of the hole is not less than the volume of the working fluid necessary to obtain the estimated thickness of the coating, and the method includes applying a coating to the surface of the hole during the galvanomechanical treatment with a conductive tool, and differs in that the above tool is used as a conductive tool, which is introduced in the hole filled with the working fluid with providing contact with the surface of the hole of at least two wire strips, include direct current reverse second polarity and move the tool with a force proportional to the variable thickness of the layer deposited on the surface of the hole, and the limited tensile strength at break of the conductive tool.

The proposed tool and method are shown in figure 1 and figure 2. Figure 1 presents the main elements of the device and the scheme of the method. Figure 2 shows the mechanism of coating the surface of the holes of small diameter.

Figure 1 shows the Central hole 1 in the nozzle 2 and the hole 3 in the wall of the nozzle 2. In the Central hole 1 is a tool 4 with deposited wear-resistant hard narrow belts 5, 6, 7, 8 having an outer size l ₁ , l ₂ , l ₃ (Fig. 2), which decreases in the direction of the tool entering the hole 3. The last girdle 8 (Fig. 1) has an outer dimension equal to the size of the hole 3 after calibration. The step 9 between the belts is approximately equal to half the length 10 of the hole 3. When calibrating, the space between the tool 4 and the hole 3 is filled with a working fluid 11 containing metal deposited on the surface of the hole 3 in the form of a coating 12 (FIG. 2). During calibration, tool 4 is moved along hole 3 with force P.

The method is as follows. In the process of testing the nozzle 2, a hole 3 is installed in the wall of the nozzle 2, requiring calibration with a decrease in size. Enter into the installed hole 3 in the wall of the nozzle 2 a tool 4 with belts 5, 6, 7, 8 (Fig. 1), fill the central hole 1 of the nozzle 2 with a working fluid 11 with a level higher than the location of the hole 3, perform a reciprocating movement of the tool 4 to filling the space between the tool 4 and the hole 3 with the working fluid 11, install strips 5, 7 with dimensions l ₁ , l ₂ , l ₃ (for round holes 3, the dimensions l ₁ , l ₂ , l ₃ will be respectively diameters d ₁ , d ₂ , d ₃₎ . They are installed in the hole 3 so that they are in contact with the extreme sections of the hole 3 with a length of 10. Step 9 between adjacent belts is selected depending on the length 10 of the hole 3 so that at least two bands are always in contact with the hole 3, which eliminates the possibility of short circuits between the tool 4 and the hole 3. Turn on the direct current with the reverse polarity shown in figures 1, 2. Apply the rated force P to the tool 4 and begin to move with the rated speed of the tool 4 with belts 5, 6, 7, 8 supporting it by changing the force P. During the passage of the hole 3 with belts 5, 6, 7, a high-quality coating layer 12 with the required thickness is applied to the surface of the hole 3. The length of the tool is calculated by the number of applied coating layers 12 required to calibrate the hole 3.

According to the known size of the hole 3 after calibration, the coating thickness (h) is set on the side of the hole 3. According to recommendations from literary sources [see, for example, M.I. Chizhov, V.P. Smolentsev. "Galvanomechanical chrome plating of machine parts." Voronezh: VSTU, 1998. - 162 p.] We select the thickness of a single high-quality layer (h ₁ ), after which we find the required number of layers (n)

The speed of the tool (V _and ) is selected according to the specified source [M.I. Chizhov, V.P. Smolentsev. "Galvanomechanical chrome plating of machine parts." Voronezh: VSTU, 1998. - 162 p.].

единичного качественного слоя в отверстии с периметром сечения П (в частном случае для круглого отверстия П=πd, где d - диаметр отверстия на рассматриваемом этапе калибровки). При длине отверстия L объем рабочей жидкости 11 должен быть не менее V_ж The minimum volume of working fluid necessary for the formation of one coating layer of chromium is found according to [M. Chizhov, V.P. Smolentsev. "Galvanomechanical chrome plating of machine parts." Voronezh: VSTU, 1998. - 162 pp.] (Universal chromium electrolyte with a metal chromium content of about 3.5% by volume is recommended). Then, during the passage of the tool 4 through the hole 3 steps (h _W ) between adjacent strips, it is necessary to obtain a coating in the form of half $$\left(\frac{\mathrm{one}}{2}{h}_{\mathrm{one}}\right)$$

single quality layer in the hole with the perimeter of the section П (in the particular case for a round hole П = πd, where d is the diameter of the hole at the calibration stage under consideration). When the length of the hole L, the volume of the working fluid 11 must be at least V _W

where V ₀ is the total volume of electrolyte; V _m is the volume of chromium in the electrolyte. Force P is calculated according to [Combined processing methods / Ed. V.P. Smolentseva. Voronezh: VSTU, 1996. - 168 p.], Whence for a circular hole with a diameter of d the formula will take the form

where P _to - contact force, which is chosen according to [M.I. Chizhov, V.P. Smolentsev “Galvanomechanical chromium plating of machine parts”, Voronezh: VSTU, 1998. - 162 p.]; f is the coefficient of friction of the material of the belts on the coating 12.

An example implementation of the method. In the nozzle made of 1X18H10T alloy, one of the 6 radial holes with a diameter of 0.13 mm and a length of 1.5 mm has a diameter of 0.15 mm and it is necessary to apply a coating with a thickness of 10 μm per side into the hole.

By [M.I. Chizhov, V.P. Smolentsev. "Galvanomechanical chrome plating of machine parts." Voronezh: VSTU, 1998. - 162 p.] We choose the thickness of a single high-quality coating layer (h ₁ = 1 μm). To calibrate the hole, it is required (see formula (1)) to apply 10 layers of chromium.

The volume of liquid according to the formula (2) will be 0.005 mm ³ . Hence the diameter of the round tool is 0.08 mm.

мкм. Контактная сила Р_к по [М.И. Чижов, В.П. Смоленцев. «Гальваномеханическое хромирование деталей машин». Воронеж: ВГТУ, 1998. - 162 с.] составляет 0,1 МПа. Тогда сила Р=0…4,2 Н; сечение проволоки 0,0048 мм². Предельное напряжение 875 Н/мм². Стандартное значение предела прочности вольфрамовой проволоки на разрыв 900 Н/мм², что обеспечивает работоспособность инструмента.The force P is calculated by the formula (3), gradually increasing to $$\frac{\mathrm{one}}{2}{h}_{\mathrm{one}}=0,5$$

microns. Contact force P _to [M.I. Chizhov, V.P. Smolentsev. "Galvanomechanical chrome plating of machine parts." Voronezh: VSTU, 1998. - 162 p.] Is 0.1 MPa. Then the force P = 0 ... 4.2 N; wire cross section 0,0048 mm ² . The ultimate stress is 875 N / mm ² . The standard value of the tensile strength of a tungsten wire at a break of 900 N / mm ² , which ensures the operability of the tool.

Thus, the proposed method provided a calibrated nozzle and eliminated the marriage of the part.

Claims (2)

1. A tool for calibrating small holes in nozzles, made in the form of a conductive wire with non-conductive wear-resistant hard narrow belts applied, the outer diameter of which decreases along the length of the wire in proportion to the thickness of the coating, the outer diameter of the last girdle being equal to the outer diameter of the hole after calibration, and the pitch between the belts is not more than half the length of the calibrated hole, and with ensuring the space between the conductive wire and the surface th opening of hole length not less than the working volume of fluid required to obtain the calculated coating thickness. 2. A method for calibrating small holes in nozzles, including coating the surface of the hole during galvanic mechanical treatment with a conductive tool, characterized in that the tool according to claim 1 is used as a conductive tool, which is inserted into the hole filled with the working fluid to ensure contact with the surface of the hole at least two non-conductive tool belts and when the reverse polarity constant current is switched on, the tool is moved with a force that changes the proportion tional thickness of the layer deposited on the surface of the hole, and the limited tensile strength at break tool.

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