Machining tool and combined machining method for radial eccentric stepped hole of injector disc

Abstract

The invention relates to a machining tool and a combined machining method for a radial eccentric stepped hole of an injector disc, and belongs to the field of eccentric stepped hole machining. The machining tool comprises a detachable guide drill, a detachable reamer, a detachable rose reamer and a detachable reamer. According to the structural characteristics of a cutter and a product, eccentric stepped hole machining is divided into four stage processes of drilling, broaching, chamfering and reaming, and drilling, broaching and chamfering, allowance removal and finishing machining are sequentially completed. And step-by-step machining of the eccentric chamfering stepped hole is achieved. The cutter material, the coating, the cutting edge angle and the cutter split structure are machined step by step, the service life of the cutter is prolonged, and the machining efficiency is improved by more than three times. The combined machining method is adopted, cutter deflection is effectively restrained, chamfering uniformity errors are reduced, aperture control is improved, the roughness of the inner surface of the hole is reduced, the machining efficiency of the injector disc is improved, and the combined machining method is suitable for efficient and precise machining of the spaceflight complex step eccentric hole.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of eccentric step hole machining, and particularly relates to a kind of injector disc radial eccentric step hole machining tools and composite machining methods. BACKGROUND

[0002] The injector disc of rocket engine is an important part of the engine thrust chamber, mainly used for distributing, atomizing and mixing propellant, and ensuring stable combustion of propellant according to the required mixing ratio. The material of the injector disc is 1Cr18Ni9Ti, which is a difficult-to-machine material. The Ti component in the material is easy to stick to the tool due to its low melting point, and is easy to form a built-up edge, which affects the surface machining quality. The radial hole is located on the inside of the injector disc, and the radial hole has one layer, two layers and three layers of holes. The two layers and three layers of steps are eccentric step holes. During the machining of the eccentric hole, the removal allowance is large, the cutting force is large, the chip removal is difficult, the cutting edge is unevenly stressed, the tool is prone to deflection, which leads to different step hole axial non-parallelism, and affects the product performance. The eccentric step hole of the injector disc needs to meet the following requirements: straightness of deep hole, total depth of third layer hole is more than 200mm, axial deviation is less than or equal to 0.1mm; chamfer consistency, chamfer angle tolerance of each step is ±0.5°; surface quality, hole wall roughness Ra is less than or equal to 0.4μm.

[0003] The traditional machining method of the radial eccentric hole of the injector disc is to use a general tool on a radial drill equipment. The process scheme of manual drilling + hole expanding + manual polishing is adopted, and the hole is drilled and expanded layer by layer from one layer to three layers under the guidance of a drill sleeve. The uniform angle, position and size are guaranteed by the drill jig, and the hole diameter is guaranteed by the tool. The traditional machining method has the following problems: low machining efficiency, frequent replacement of drill sleeve by toolmaker during product machining process, and cleaning of iron chips; poor surface quality, obvious drilling lines and scratches exist on the inner hole surface after machining, which need to be polished manually to ensure the quality of the hole; difficult chip removal, the accumulated chips in deep hole machining can scratch the hole wall; short tool life, the drill is quickly worn due to the material of the injector disc. SUMMARY

[0004] The purpose of the present application is to provide a kind of injector disc radial eccentric step hole machining tool and composite machining method. Through the synergistic effect of step-by-step machining tool, high-efficiency and precision machining of the radial eccentric step hole of the injector disc on the numerical control machine tool is realized, and the product quality is effectively guaranteed.

[0005] The above-mentioned purpose of the present application is mainly realized by the following technical scheme:

[0006] A kind of injector disc radial eccentric step hole machining tool, including detachable guide drill, detachable hole expanding drill, detachable chamfering tool and detachable reamer, wherein,

[0007] A detachable pilot drill comprises a pilot drill bit and a pilot drill shank, wherein the pilot drill bit is fixed to the front end of the pilot drill shank;

[0008] The detachable reamer includes a reamer blade, a reamer head and a reamer shank. The reamer blade is fixed to the front end of the reamer head, and the rear end of the reamer head is connected to the reamer shank. The front end of the reamer blade includes a cutting edge and a chamfering edge.

[0009] The detachable chamfering tool comprises a chamfering tool blade, a chamfering tool head and a chamfering tool rod. The chamfering tool blade is fixed to the front end of the chamfering tool head, and the rear end of the chamfering tool head is connected to the chamfering tool rod.

[0010] The detachable reamer comprises a reamer body and a reamer rod, and the front end of the blade of the reamer body comprises a cutting edge and a chamfering edge.

[0011] A U-shaped groove is provided on the top of the guide drill rod, and the guide drill bit is inserted into the U-shaped groove. Surface positioning is achieved through the guide drill positioning surface at the bottom of the guide drill bit to fix the circumferential direction of the guide drill bit; internal threads are provided at the corresponding positions of the bottom surface of the guide drill bit and the guide drill rod head, and the guide drill bit and the guide drill rod are connected through the internal threads to fix the axial direction of the guide drill bit.

[0012] The guide drill bit is made of YW-type cemented carbide, and the surface is coated with ALtima coating with a coating thickness of 4-6 μm; the guide drill bit is a double-edged drill bit.

[0013] The guide drill bit has a drill tip angle of 135-140°, a front angle of 3-5°, a back angle of 10-13°, and a helix angle of 35-40°; the guide drill shank has a spiral structure with a helix angle of 35-40°, and a spiral internal cooling channel is provided in the guide drill shank, and the diameter of the spiral internal cooling channel is 2-3 mm.

[0014] The front angle of the reamer blade is 3-5°, the back angle 1 is 10-15°, and the back angle 2 is 20-25°; the bottom surface of the reamer blade is W-shaped, and a W-shaped groove structure is provided on the top of the reamer head. The planes on both sides of the reamer blade are the reamer positioning surfaces. The reamer blade is inserted into the W-shaped groove, and surface positioning is achieved through the reamer positioning surface. The reamer blade and the reamer head are connected by screws to achieve axial fixation.

[0015] The reaming drill bit is connected to the reaming drill rod through threads, and the threads at the tail of the reaming drill bit are left-hand threads.

[0016] The reamer drill blade is made of JC7550 cemented carbide, and a TiAlN composite coating is provided on the surface of the reamer drill blade with a coating thickness of 3-5 μm;

[0017] An internal cooling channel (204) for the reamer is provided inside the reamer shank (203) and the reamer head (202). The internal cooling channel (204) for the reamer is Y-shaped and has a diameter of 2-3 mm.

[0018] The chamfering blade is a diamond-shaped sheet structure, with a groove provided on the side of the chamfering blade, and the chamfering cutter head is provided with a corresponding diamond-shaped groove, and a boss corresponding to the chamfering blade groove is provided in the diamond groove; after the chamfering blade is inserted into the chamfering cutter head, axial positioning is achieved by screw connection.

[0019] Three chamfering blades are evenly arranged on the top of the chamfering cutter head. The angle between the chamfering cutter blade edge and the horizontal axis of the top of the chamfering cutter head is 40-45 degrees. There are two cutting edges on both sides of the chamfering cutter blade. A chamfering cutter internal cooling channel is provided in the chamfering cutter head. The diameter of the chamfering cutter internal cooling channel is 2-3mm.

[0020] The reamer body has a front angle of 7-12 degrees, a back angle of 11-15 degrees, and a back angle of 20-25 degrees.

[0021] A composite machining method for a radial eccentric stepped hole of an injector disc is provided, wherein the machining is performed using the above-mentioned machining tool, and specifically comprises the following steps:

[0022] (1) Use a detachable guide drill to process the base hole;

[0023] (2) using a detachable reaming drill to reame and chamfer the base hole obtained in step (1);

[0024] (3) removing the eccentric chamfering allowance of the circular hole obtained in step (2) by a detachable chamfering cutter;

[0025] (4) using a detachable reamer to perform aperture finishing on the circular hole obtained in step (3);

[0026] (5) Replace the cutting tool with a different specification and repeat the operations described in steps (1) to (4) to complete the multi-layer eccentric step hole processing.

[0027] Compared with the prior art, the present invention has at least the following beneficial effects:

[0028] (1) The cutting tools of the present invention are all designed to be split, and the blades are easy to disassemble. When the blades are worn, only the blades need to be replaced, which greatly saves the cost of cutting tools;

[0029] (2) The composite processing method of the present invention adopts a step-by-step chamfering method, which can reduce tool wear caused by uneven force on the eccentric hole through four steps: processing the base hole, expanding the hole and chamfering, removing the chamfer allowance, and fine reaming and finishing;

[0030] (3), the aperture and surface roughness are completed by the reamer, and the product quality is improved

[0031] (4), the tool and the machining method improve the machining efficiency by 3 times, can realize machining in a numerical control machining center, and are suitable for mass processing. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is a detachable guide drill structure schematic diagram of the application;

[0033] Figure 2 It is a detachable reamer structure schematic diagram of the application;

[0034] Figure 3 It is a chamfering tool structure schematic diagram of the application;

[0035] Figure 4 It is a detachable reamer structure schematic diagram of the application;

[0036] Figure 5 It is a three-layer eccentric hole structure schematic diagram of the injector disc of the application;

[0037] Figure 6 It is a radial hole schematic diagram of the injector disc of the application. DETAILED DESCRIPTION

[0038] The application will be further described in detail below in combination with the drawings and specific embodiments:

[0039] As Figure 5 shown is a three-layer eccentric hole structure schematic diagram of the injector disc of the application; Figure 6 shown is a radial hole schematic diagram of the injector disc of the application.

[0040] The detachable distributed machining tool comprises a detachable guide drill, a detachable reamer, a detachable chamfering tool and a detachable reamer.

[0041] As Figure 1As shown, the detachable guide drill of the present application comprises a guide drill bit 101 and a guide drill tool bar 102, the top of the guide drill tool bar 102 is a U-shaped groove structure, when installed, the guide drill bit 101 is inserted into the U-shaped groove at the top of the guide drill tool bar 102, the bottom guide drill positioning surface 103 of the guide drill bit 101 is positioned with the bottom plane of the U-shaped groove of the guide drill tool bar 102, and the left and right sides of the guide drill bit 101 are each positioned with the left and right sides of the U-shaped groove at the top of the guide drill tool bar 102, for fixing the circumferential direction of the guide drill bit 101. The bottom of the guide drill bit 101 and the head of the guide drill tool bar 102 are internally threaded, the guide drill bit 101 and the guide drill tool bar 102 are connected by a stud bolt, and the axial direction of the guide drill bit 101 is fixed. The guide drill bit 101 and the guide drill tool bar 102 are fixed by a stud bolt and a positioning surface, which ensures stable and reliable connection.

[0042] The material of the guide drill bit 101 is YW type hard alloy, and the surface is coated with ALtima coating with a thickness of 4-6 μm. The affinity with Ti material can be reduced and the tool life can be improved. The design angle of the drill tip is 135°-140°, the rake angle of the guide drill bit 101 is 3°-5°, the relief angle is 10°-13°, and the helix angle is 35°-40°, which can effectively prevent the guide drill bit 101 from yawing when drilling a circular arc surface. The guide drill bit 101 adopts a double-edge design to facilitate even force distribution during chip removal cutting. The guide drill tool bar 102 is made of high-strength alloy steel, which has the characteristics of good rigidity, strong shock resistance, economy and practicality. The guide drill tool bar 102 is spiral in structure, with a helix angle of 35°-40°, and a spiral internal cooling channel (diameter 2mm-3mm) is provided inside the guide drill tool bar 102 for reducing cutting temperature and facilitating chip removal. According to the processing size of the radial eccentric hole of the injector disc, three specifications of detachable guide drills of φ20, φ24 and φ30 are designed.

[0043] As Figure 2As shown, the detachable reaming drill includes a reaming drill insert 201, a reaming drill head 202, and a reaming drill rod 203. The bottom surface of the reaming drill insert 201 is W-shaped. The top of the reaming drill head 202 is a W-shaped groove structure. When installed, the reaming drill insert 201 is inserted into the W-shaped groove along the top of the reaming drill head 202. The two side planes of the reaming drill insert 201 are reaming drill positioning surfaces 205, which realize surface positioning with the two side planes of the W-shaped groove at the top of the reaming drill rod 203. The bottom of the reaming drill insert 201 is embedded in the W-shaped groove, realizing bottom surface positioning of the reaming drill head 202, for fixing the circumferential direction of the reaming drill insert 201 and the position of the reaming drill insert 201. The reaming drill insert 201 and the reaming drill head 202 are connected and fixed in the axial direction by screws. The reaming drill insert 201 and the reaming drill head 202 are fixed by screws and positioning surfaces. The reaming drill head 202 and the reaming drill rod 203 are connected by threads. The threads at the tail of the reaming drill head 202 are left-handed threads. In order to prevent the reaming drill head 202 from loosening during processing and to ensure stable and reliable connection.

[0044] The material of the reaming drill insert 201 is JC7550 cemented carbide. The surface of the reaming drill insert 201 is entirely deposited with a TiAlN composite coating, and the thickness of the coating is 3-5 μm. It can cope with various cutting materials and prolong the tool processing life. The front end of the reaming drill insert 201 is designed as a 180° flat bottom cutting edge and a 45° chamfered edge. The rake angle of the reaming drill insert 201 is 3°-5°, the 1 relief angle is 10°-15°, and the 2 relief angle is 20°-25°, which is used for rough machining of eccentric chamfers and hole bottoms, does not need positioning holes, and does not need step-by-step feeding, which can ensure stable machining. The reaming drill head 202 and the reaming drill rod 203 are made of high-strength alloy steel, which has high rigidity and high shock resistance. The reaming drill rod 203 and the reaming drill head 202 are internally provided with a reaming drill internal cooling channel 204 (diameter 2 mm-3 mm), which is Y-shaped in distribution, for reducing cutting temperature and facilitating chip removal. According to the processing size of the radial eccentric hole of the injector disc, φ20, φ24, and φ30 detachable reaming drills of three specifications are designed.

[0045] As Figure 3As shown, the detachable chamfering tool includes a chamfering tool blade 301, a chamfering tool head 302 and a chamfering tool rod 303. The chamfering tool blade 301 is in a rhombic sheet structure, the center of the chamfering tool blade 301 is a threaded through hole, and there are grooves on the two side surfaces of the chamfering tool blade 301. The chamfering tool head 302 is installed at the chamfering tool blade 301 and is in a rhombic groove, two bosses are protruded in the middle of the groove, and the center of the groove is a threaded hole. When the chamfering tool blade 301 is installed, the chamfering tool blade 301 is placed in the rhombic groove of the chamfering tool head 302, the bottom surface of the chamfering tool blade 301 is positioned with the bottom surface of the groove of the chamfering tool head 302, the two bosses of the groove are in contact with the grooves on the two side surfaces of the chamfering tool blade 301 to realize surface positioning, and circumferential positioning is realized; the chamfering tool blade 301 and the chamfering tool head 302 are connected by screws to realize axial positioning. The chamfering tool head 302 and the chamfering tool rod 303 are connected by threads. The threads at the tail of the chamfering tool head 302 are left-handed threads, in order to prevent the chamfering tool head 302 from loosening during processing and to ensure stable and reliable connection.

[0046] The chamfering tool blade 301 is arranged at an interval of 120°, the cutting edge of the chamfering tool blade 301 is at an angle of 40°-45° with the horizontal axis of the chamfering tool head 302, the chamfering tool blade 301 is made of JC7550 hard alloy material, there are two cutting edges on each surface of the chamfering tool blade 301, the unworn edge is switched by rotating or overturning during chamfering processing, the single chamfering tool blade 301 can be used for 4 times, and the service life is increased by 400%. The chamfering tool head 302 and the chamfering tool rod 303 are made of high-strength alloy steel material and have the characteristics of high rigidity and high shock resistance. The chamfering tool head 302 is internally provided with a chamfering tool internal cooling channel 305 (diameter 2mm-3mm), the internal cooling hole is in Y-shaped distribution, and there are three chip removal grooves on the chamfering tool head 302 for facilitating cooling and chip removal. According to the processing size of the radial eccentric hole of the injector disc, two specifications of detachable chamfering tools are designed.

[0047] As Figure 4As shown, the detachable reamer includes a reamer body 401 and a reamer rod 402, which are connected by threads, and the threads at the tail of the reamer body 401 are left-handed threads, so as to prevent loosening of the reamer body 401 during machining and ensure stable and reliable connection. The blade part of the reamer body 401 is made of PCBN material to improve the hardness and wear resistance of the blade part, and the connection part of the tail of the reamer body 401 and the reamer rod 402 is made of high-strength alloy steel to improve toughness and avoid damage to the threaded connection part. The tail of the reamer body 401 and the blade part are welded to form a body, the front end of the blade of the reamer body 401 is designed as a 180° flat cutting edge and a 45° chamfering edge, the front angle of the body is 7°-12°, the first rear angle is 11°-15°, the second rear angle is 20°-25°, and the inner cooling hole is Y-shaped and distributed in the chip removal groove to reduce the cutting temperature and facilitate chip removal; the surface roughness Ra is ≤0.4 μm. The reamer rod 402 is made of high-strength alloy steel and has high rigidity and high shock resistance. According to the machining size of the radial eccentric hole of the injector disc, three specifications of detachable chamfering reamer are designed.

[0048] Example 1

[0049] Taking the second layer step hole machining as an example, the following steps are included:

[0050] (1) Drilling a two-layer base hole, using a φ24mm detachable guide drill, the speed is 800-1200 rpm, the feed is 0.05-0.1 mm / r, the internal cooling pressure is 8-12 MPa, and the machining depth is 148 mm;

[0051] (2) Hole expansion and chamfering forming, using a φ24mm detachable hole expansion drill, the speed is 500-800 rpm, the feed is 0.03-0.06 mm / r, the hole is expanded to φ24mm synchronously and the bottom chamfer is formed;

[0052] (3) Chamfering excess removal, using a φ30mm detachable chamfering tool, the speed is 200-400 rpm, the feed is 0.02-0.04 mm / r, and the eccentric chamfering excess is removed;

[0053] (4) Fine reaming and finishing, using a φ30mm detachable reamer, the speed is 150-300 rpm, the feed is 0.01-0.03 mm / r, the excess is 0.05-0.1 mm, and the hole diameter and chamfer are finished.

[0054] The above is only the best specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any change or replacement within the technical range disclosed by the present application can be easily thought by those skilled in the art, which should be covered within the protection scope of the present application.

[0055] The description herein of any aspect of the application is not meant to be limiting of that aspect of the application. For example, features of one aspect of the application can be interchanged with features of another aspect of the application.

Claims

1. A tool for machining radial eccentric stepped holes in an injector disc, characterized by: It includes a detachable pilot drill, a detachable reaming drill, a detachable chamfering cutter and a detachable reamer, wherein: A detachable guide drill comprises a guide drill bit (101) and a guide drill shank (102), wherein the guide drill bit (101) is fixed to the front end of the guide drill shank (102); The detachable reamer comprises a reamer blade (201), a reamer head (202) and a reamer shank (203); the reamer blade (201) is fixed to the front end of the reamer head (202); the rear end of the reamer head (202) is connected to the reamer shank (203); the front end of the reamer blade (201) comprises a cutting edge and a chamfering edge; The detachable chamfering tool comprises a chamfering tool blade (301), a chamfering tool head (302) and a chamfering tool rod (303), wherein the chamfering tool blade (301) is fixed to the front end of the chamfering tool head (302), and the rear end of the chamfering tool head (302) is connected to the chamfering tool rod (303); The detachable reamer comprises a reamer body (401) and a reamer rod (402); the front end of the blade of the reamer body (401) comprises a cutting edge and a chamfering edge.

2. The tool for machining radial eccentric stepped holes in an injector disc according to claim 1, characterized in that: A U-shaped groove is provided on the top of the guide drill rod (102), and the guide drill bit (101) is inserted into the U-shaped groove. Surface positioning is achieved through the guide drill positioning surface (103) at the bottom of the guide drill bit (101), thereby fixing the circumferential direction of the guide drill bit (101); internal threads are provided at corresponding positions on the bottom surface of the guide drill bit (101) and the head of the guide drill rod (102), and the guide drill bit (101) and the guide drill rod (102) are connected through the internal threads, thereby fixing the axial direction of the guide drill bit (101).

3. The tool for machining radial eccentric stepped holes in an injector disc according to claim 1, characterized in that: The guide drill bit (101) is made of YW-type hard alloy, and its surface is coated with an ALtima coating with a coating thickness of 4-6 μm; the guide drill bit (101) is a double-edged drill bit.

4. The tool for machining radial eccentric stepped holes in an injector disc according to claim 1, characterized in that: The guide drill bit (101) has a drill tip angle of 135-140°, a front angle of 3-5°, a back angle of 10-13°, and a helical angle of 35-40°; the guide drill shank (102) is a spiral structure with a helical angle of 35-40°; a spiral internal cooling channel is provided in the guide drill shank (102), and the diameter of the spiral internal cooling channel is 2-3 mm.

5. The tool for machining radial eccentric stepped holes in an injector disc according to claim 1, characterized in that: The front angle of the reamer blade (201) is 3-5 degrees, the back angle is 10-15 degrees, and the back angle is 20-25 degrees; the bottom surface of the reamer blade (201) is W-shaped, and the top of the reamer head (202) is provided with a W-shaped groove structure. The two side planes of the reamer blade (201) are reamer positioning surfaces (205). The reamer blade (201) is inserted into the W-shaped groove, and surface positioning is achieved through the reamer positioning surface (205). The reamer blade (201) and the reamer head (202) are connected by screws to achieve axial fixation.

6. The tool for machining radial eccentric stepped holes in an injector disc according to claim 1, characterized in that: The reaming drill bit (202) is connected to the reaming drill rod (203) through a thread, and the thread at the tail of the reaming drill bit (202) is a left-hand thread.

7. The tool for machining radial eccentric stepped holes in an injector disc according to claim 1, characterized in that: The reamer drill blade (201) is made of JC7550 hard alloy, and a TiAlN composite coating is provided on the surface of the reamer drill blade (201), with a coating thickness of 3-5 μm; An internal cooling channel (204) for the reamer is provided inside the reamer shank (203) and the reamer head (202). The internal cooling channel (204) for the reamer is Y-shaped and has a diameter of 2-3 mm.

8. The tool for machining radial eccentric stepped holes in an injector disc according to claim 1, characterized in that: The chamfering blade (301) is a diamond-shaped sheet structure, a groove is provided on the side of the chamfering blade (301), and the chamfering cutter head (302) is provided with a corresponding diamond-shaped groove, and a boss corresponding to the groove of the chamfering blade (301) is provided in the diamond-shaped groove; after the chamfering blade (301) is inserted into the chamfering cutter head (302), axial positioning is achieved by screw connection.

9. The tool for machining radial eccentric stepped holes in an injector disc according to claim 1, characterized in that: Three chamfering blades (301) are evenly arranged on the top of the chamfering blade head (302), the angle between the chamfering blade (301) and the horizontal axis of the top of the chamfering blade head (302) is 40-45 degrees, two left and right cutting edges are arranged on both sides of the chamfering blade (301), and a chamfering blade internal cooling channel (305) is arranged in the chamfering blade head (302), and the diameter of the chamfering blade internal cooling channel (305) is 2-3 mm.

10. The tool for machining radial eccentric stepped holes in an injector disc according to claim 1, characterized in that: The reamer body (401) has a front angle of 7-12°, a back angle of 11-15°, and a back angle of 20-25°.

11. A composite machining method for a radial eccentric stepped hole of an injector disk, characterized in that: The processing method using the processing tool according to any one of claims 1 to 10 specifically includes the following steps: (1) Use a detachable guide drill to process the base hole; (2) using a detachable reaming drill to reame and chamfer the base hole obtained in step (1); (3) removing the eccentric chamfering allowance of the circular hole obtained in step (2) by a detachable chamfering cutter; (4) using a detachable reamer to perform aperture finishing on the circular hole obtained in step (3); (5) Replace the cutting tool with a different specification and repeat the operations described in steps (1) to (4) to complete the multi-layer eccentric step hole processing.

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