CN107900421A - For processing the ladder drilling reamer of aircraft skin rivet hole - Google Patents

Abstract

The invention provides a stepped drill reamer for processing aircraft skin rivet holes, which can solve the problems of low processing efficiency, high production cost and unsatisfactory processing quality existing in the existing traditional processing methods. The cutter body includes a first cylinder and a second cylinder that are connected concentrically from front to back. The diameter D1 of the first cylinder is smaller than the diameter D2 of the second cylinder; two symmetrical first rows along the center are arranged on the outer peripheral surface of the first cylinder. There are two chip flutes on the outer peripheral surface of the first cylinder, two second chip flutes symmetrical along the center are opened on the outer peripheral surface of the second cylinder, and the two first chip flutes on the outer peripheral surface of the first cylinder are both Extending to the outer peripheral surface of the second cylinder, the first chip removal groove on the second cylinder is attached to the second chip removal groove, and the two first chip removal grooves and the two second chip removal grooves on the second cylinder connect the first chip removal groove to the second cylinder. The outer peripheral surface of the two cylinders is divided to form two peripheral edges, each blade on the first cylinder is connected to the corresponding peripheral edge on the second cylinder through a step angle transition, and the core thickness of the first flute d1=0.25D1 ~0.35D1, the core thickness of the second flute d2=0.25D2~0.35D2, and d1 is smaller than d2.

Description

Step drill reamer for machining rivet holes in aircraft skin

technical field

The invention relates to the field of mechanical processing, in particular to a step drill reamer used for processing aircraft skin rivet holes.

Background technique

The riveted structure has good connection strength and reliability, and is the most important connection method in aircraft assembly, and riveting accounts for more than 70% of all connection methods in aircraft installations. Riveting is mainly used in the skin parts of aircraft, such as the connection between aircraft skin and skin, between skin and frame, between skin and rib, and between skin and other components, and it is also used in girder assembly , the assembly and connection of ribs, frames, ribs and strips, the installation of accessories on various parts, and the joining of a large number of supports and other components.

The riveted structure is one of the parts that are prone to failure in the aircraft structure. It is not only a key part of the static strength check, but also a key part of the fatigue life check. Therefore, the processing quality of the rivet hole is particularly important.

The traditional rivet hole processing, especially the rivet hole processing on the arc surface of the aircraft skin, first mills a small plane on the arc surface, then drills the rivet hole with a drill, and then reams the rivet hole with a reamer, and then Use a chamfering knife to process the chamfering surface; at present, this traditional method is used in the processing of rivet holes in the aircraft skin, because it needs to be processed sequentially with a drill bit, a reamer, and a chamfering knife, which not only takes up more storage space in the tool magazine, but also Moreover, frequent tool changes lead to low production tact, low processing efficiency, and high production costs; especially in the processing of rivet holes on arc surfaces, there is often a problem that the centerline of the chamfered hole and the centerline of the base hole cannot coincide, which leads to a step The coaxiality and position of the hole are poor; in addition, when drilling and reaming with ordinary drills and reamers, burrs are easy to occur at the exit, and the surface roughness of the hole is poor, and the large margin cutting of the chamfering knife often causes The phenomenon of knife vibration occurs, and in serious cases, it is easy to cause the knife to break or even break, which seriously affects production safety.

Sometimes in order to save tool costs, a step chamfering drill is designed to process rivet holes and chamfering surfaces at one time; but when the diameter reduction ratio exceeds 2 times the diameter, the design of the conventional step drill often occurs during manufacturing. The back width of the first step is extremely narrow, and the tool rigidity is poor, so it cannot meet the straightness requirement of the rivet hole; and in order to ensure the back width of the first step, the radial rake angle of the second step is particularly large, so when processing the chamfer of the rivet hole Occasionally, the knife vibration phenomenon will occur again, so the processing quality of the rivet hole cannot be guaranteed.

Contents of the invention

In view of the above problems, the present invention provides a step drill reamer for processing aircraft skin rivet holes, which can solve the problems of low processing efficiency, high production cost and unsatisfactory processing quality existing in the existing traditional processing methods.

Its technical solution is a stepped drill reamer for processing aircraft skin rivet holes, which includes a handle with a diameter of D3 and a cutter body concentrically arranged at the front end of the handle, and the cutter body includes a front-to-back A first cylinder and a second cylinder concentrically connected together, the diameter D1 of the first cylinder is smaller than the diameter D2 of the second cylinder, characterized in that: the first cylinder is a drill head, and the second cylinder is In the reamer part, two first chip flutes symmetrical along the center are opened on the outer peripheral surface of the first cylinder and two blade lobes are formed on the outer peripheral surface of the first cylinder, and the outer peripheral surface of the second cylinder is There are two second chip flutes that are symmetrical along the center, and the two first chip flutes on the outer peripheral surface of the first cylinder both extend to the outer peripheral surface of the second cylinder, and the first row on the second cylinder The chip flute is attached to the second chip flute, and each of the two chip flutes and the two second chip flutes on the second cylinder divide the outer peripheral surface of the second cylinder to form two peripheral edges. , each blade on the first cylinder is connected to the corresponding peripheral edge on the second cylinder through a step angle transition, and the core thickness of the first flute d1=0.25D1～0.35D1, so The core thickness of the second flute d2=0.25D2˜0.35D2, and d1 is smaller than d2.

Further, the tip of the front end of the first cylinder is provided with an apex angle θ, and the apex angle θ ranges from 150° to 170°.

Further, a knife tip chamfer is provided at the corner of the tip of the front end of the first cylinder and the blade.

Further, both ends of the top surface of the two blades on the first cylinder are provided with a first margin and a third margin, and the middle part of the top surface is provided with a second margin, wherein the first margin is The cylindrical margin, the second margin and the third margin are formed at the first cylindrical surface grinding relief angle α, and the diameter D4 of the circumference where the second margin and the third margin are located is smaller than the The circumferential diameter D1 of the first land is described.

Further, the stepped corner has a multi-relief structure, and a circular arc-shaped damping land is provided at the adjoining place between the stepped corner and the second flute, and the relief angle of the damping land is 2°-5°, and the width d of the damping land is 0.05-0.1 mm.

Further, chip breakers are respectively provided on the two stepped corners, one chip breaker is provided on one of the stepped corners, and two chip breakers are provided on the other stepped corner.

The beneficial effects of the present invention are:

(1) The cutter body is composed of a first cylinder and a second cylinder concentrically connected from front to back, and the diameter D1 of the first cylinder is smaller than the diameter D2 of the second cylinder so as to form a stepped compound cutter, and the first cylinder As the drill head and the second cylinder as the reamer part, drilling, reaming and chamfering can be completed in one process, effectively improving the processing cycle, improving processing efficiency, and occupying less tool magazine space;

(2) The first flute opened on the first cylinder extends to the second cylinder and is attached to the second flute opened on the second cylinder. The core thickness d1 of the first flute is smaller than that of the second The core thickness d2 of the chip flute, that is, it adopts a common flute unequal core thickness structure, so it can effectively enhance the rigidity of the tool without affecting the cutting performance and chip removal performance of the tool; at the same time, the core thickness d1 of the first chip flute = 0.25D1 ~ 0.35D1, the core thickness d2 of the second chip flute = 0.25D2 ~ 0.35D2, that is, the core thickness of the two chip flutes are designed with corresponding different cylinder diameters to further enhance the rigidity of the step drill reamer;

(3) The front end of the first cylinder adopts a large apex angle θ structure with an angle range of 150°-170°, which can effectively prevent drilling deviation on the arc surface, thereby reliably avoiding the turning point of the outer edge during drilling Large wear or chipping phenomenon, so that the radial cutting force on the drill bit is balanced as much as possible, reducing the deflection deformation of the drill bit;

(4) It improves the strength at the turning point of the outer edge of the cutting edge by providing a tip chamfer at the transition point between the tip of the first cylinder and the blade lobe, and reduces the thermal load, thereby effectively preventing the hole from being drilled when the rivet hole is drilled. The burrs in the mouth affect the assembly of the rivet head;

(5) The two margins of the first cylinder are respectively provided with three margins, and the first margin is a cylindrical margin, and the second margin and the third margin are on the first cylindrical surface The grinding relief angle α is formed, and the circumference diameter D4 where the second margin and the third margin are located is smaller than the circumference diameter D1 of the first margin, so that the first cylinder as the drill head can be positioned within the entire range of the land The hole wall forms a support, which reduces the swing and friction with the contact surface during drilling, so the straightness and roughness in the hole can be greatly improved;

(6) The step angle connecting the first cylinder and the second cylinder adopts a multi-flank structure, which can enhance the rigidity of the chamfer and prevent vibration or even collapse due to insufficient rigidity when the rivet hole is chamfered with a large margin. Knives; and the arc-shaped damping margin set at the adjacent part of the step angle and the second chip flute can play an effective damping role in the cutting process and improve the roughness of the rivet hole;

(7) Chipbreakers are respectively provided on the two stepped corners, and one chipbreaker is provided on one of the stepped corners, and two chipbreakers are provided on the other stepped corner. The asymmetrical design of the chip flute effectively reduces the tool vibration during chamfering and further improves the quality of the processed rivet hole.

Description of drawings

Fig. 1 is the structural representation of the step drill reamer that the present invention is used for processing aircraft skin rivet hole;

Fig. 2 is the schematic diagram of the three-dimensional structure of the step drill reamer used for processing aircraft skin rivet holes according to the present invention;

Fig. 3 is a schematic diagram of an enlarged structure of direction A of Fig. 1;

Fig. 4 is a partial enlarged schematic diagram of B in Fig. 3;

Fig. 5 is a schematic cross-sectional view of C-C in Fig. 4;

Fig. 6 is a partial enlarged structural schematic diagram of the first cylinder in the present invention;

Fig. 7 is the schematic diagram of the tip of the front end of the first cylinder in the present invention;

FIG. 8 is a partially enlarged schematic diagram of E in FIG. 7 .

Reference signs: 10-knife body, 11-first cylinder, 111-blade, 112-knife tip chamfering, 113-first margin, 114-second margin, 115-the third margin, 12- The second cylinder, 121-circumferential edge, 13-step angle, 14-damping land, 15-chip breaker, 20-shank, 31-first chip flute, 32-second chip flute.

Detailed ways

See Fig. 1, the stepped drill reamer that the present invention is used for processing aircraft skin rivet hole, it comprises diameter is the knife handle 20 of D3 and the cutter body 10 that is concentrically arranged at the front end of the handle, cutter body 10 includes from front to back The first cylinder 11 and the second cylinder 12 are concentrically connected into one, the diameter D1 of the first cylinder 11 is smaller than the diameter D2 of the second cylinder 12; the first cylinder 11 is the drill head, the second cylinder 12 is the reamer part, The outer peripheral surface of the cylinder 11 is provided with two symmetrical first flutes 31 along the center and two blades 111 are formed on the outer peripheral surface of the first cylinder 11, and the outer peripheral surface of the second cylinder 12 is provided with two symmetrical chips along the center. The second chip removal groove 32, the two first chip removal grooves 31 on the outer peripheral surface of the first cylinder 11 all extend to the outer peripheral surface of the second cylinder 12, the first chip removal groove 31 on the second cylinder 12 and the second chip removal groove The grooves 32 are attached and connected, and the two first flutes 31 and the two second flutes 32 on the second cylinder 12 divide the outer peripheral surface of the second cylinder 12 to form two peripheral edges 121. Each blade 111 is transitionally connected with the peripheral edge 121 on the corresponding 12 second cylinders through a step angle 13, the core thickness d1 of the first chip removal flute 31 = 0.25D1 ~ 0.35D1, the core of the second chip removal flute 32 Thickness d2=0.25D2～0.35D2, and d1 is smaller than d2. According to the traditional step drill reamer design method, if the second cylinder D2 is used as the reference, the design of the same core thickness will result in a very narrow blade back of the first cylinder D1 and poor tool rigidity; and if the first cylinder D1 is used as the Based on the design of the same core thickness, the edge back of the second cylinder D2 is very wide and the space for chip removal is small; therefore, the present invention can increase the rigidity of the stepped drill reamer by designing the core thickness according to different cylinder diameters.

See Fig. 6, the tip of the front end of the first cylinder 11 is provided with an apex angle θ, and the angle range of the apex angle θ is 150° to 170°; Chamfer 112.

Generally, the design of conventional margins will cause the axis of the entire hole to shift continuously due to insufficient support, resulting in distortion of the hole shape; and some margin designs will set 6 margins on the two blades, namely There are three margins on each blade, but since these three margins are formed on the cylindrical surface, during the drilling process, a larger support surface will increase the friction between the drill bit and the contact surface, reducing the cutting performance of the tool. And in the present invention, see Fig. 7 and Fig. 8, the two blade petals 111 top surface two ends on the first cylinder 11 are all provided with first land 113 and the 3rd land 115, the middle part of top surface is provided with second land. Land 114, wherein the first land 113 is a cylindrical land with a circumference diameter of D1, the second land 114 and the third land 115 are formed by grinding the relief angle α on the first cylindrical surface 11, and the second land 114. The diameter D4 of the circumference where the third margin 115 is located is smaller than the circumference diameter D1 of the first margin 113; the design of this margin in the present invention enables the drill bit to form a support on the hole wall within the entire blade range, reducing the Swing, and reduce the friction between the drill bit and the contact surface, which can greatly improve the straightness and roughness of the hole.

See Fig. 2 and Fig. 3, Fig. 4 and Fig. 5. The stepped corner 13 is a multi-flank structure, which can enhance the rigidity of the chamfer, and prevent the chamfering of the rivet hole hole from being cut due to insufficient rigidity. Vibration and even tool breakage; a circular arc-shaped damping land 14 is provided at the adjoining place between the step angle 13 and the second chip flute 32, and the relief angle of the damping land 14 is 2°～5°, The width d of the land 14 is 0.05-0.1 mm, which can reduce the vibration during the cutting process and improve the roughness inside the rivet hole.

In the existing rivet hole processing process, when the diameter reduction ratio of the drill reamer used for processing is greater than 3, that is, when the diameter D1 of the first cylinder 11 of the drill reamer used is equal to the diameter D2 of the second cylinder 12 When the ratio is greater than 3, the processing vibration is particularly obvious, which will cause the inner surface of the processed rivet hole to have patterns, which cannot meet the assembly requirements; the step drill reamer of the present invention adopts chip breakers 15 respectively on the two 13 step corners, See Figure 3, and one of the stepped corners 13 is provided with a chipbreaker 15, and the other stepped corner 13 is provided with two chipbreakers 15, this asymmetrical design can reduce chamfer cutting The vibrating knife generated during the process further improves the hole quality of the rivet hole being processed.

The specific implementation of the present invention has been described in detail above, but the content is only a preferred embodiment of the present invention, and cannot be considered as limiting the implementation scope of the present invention. All equal changes and improvements made according to the application scope of the present invention shall still belong to the scope covered by the patent of the present invention.

Claims (6)

1. for processing the ladder drilling reamer of aircraft skin rivet hole, it include the handle of a knife of a diameter of D3 (20) and it is concentric integratedly Cutter hub (10) arranged on the handle of a knife (20) front end, the cutter hub (10) include the first circle to link into an integrated entity with one heart from front to back Column (11) and the second cylinder (12), the diameter D1 of first cylinder (11) are less than the diameter D2 of second cylinder (12), its It is characterized in that：First cylinder (11) is bit head, and second cylinder (12) is reamer portion, first cylinder (11) Two are offered on outer circumferential surface and forms two along the first chip space of central symmetry (31) and in the outer circumferential surface of first cylinder (11) A sword valve (111), two are provided with the outer circumferential surface of second cylinder (12) along the second chip space of central symmetry (32), and described Two first chip spaces (31) of one cylinder (11) outer circumferential surface are all extended on the second cylinder (12) outer circumferential surface, and described second The first chip space (31) on cylinder (12) is depended on second chip space (32) to be connected, and two on second cylinder (12) The outer circumferential surface of second cylinder (12) is split to form two Zhou Ren by the first chip space of bar (31), two the second chip spaces (32) (121), each sword valve (111) on first cylinder (11) and the Zhou Ren on corresponding second cylinder (12) (121) connected by ladder angle (13) transition, core thickness d1=0.25D1~0.35D1 of first chip space (31) is described Core thickness d2=0.25D2~0.35D2 of second chip space (32), and d1 is less than d2.

2. the ladder drilling reamer according to claim 1 for being used to process aircraft skin rivet hole, it is characterised in that：Described The front end nose part of one cylinder (11) is equipped with vertex angle theta, and the vertex angle theta angular range is at 150 °~170 °.

3. the ladder drilling reamer according to claim 1 or 2 for being used to process aircraft skin rivet hole, it is characterised in that：Institute The front end nose part and sword valve (111) corner for stating the first cylinder (11) are equipped with point of a knife chamfered edge.

4. the ladder drilling reamer according to claim 3 for being used to process aircraft skin rivet hole, it is characterised in that：Described The top surface both ends of two sword valves (111) on one cylinder (11) are equipped with the first land (113) and the 3rd land (115), top surface Center section is equipped with the second land (114), wherein the cylindrical edge band that it is D1 that first land (113), which is circle diameter, described Second land (114) and the 3rd land (115) are to be formed in the periphery grinding relief angle α of first cylinder (11), and institute Circle diameter D4 where stating the second land (114), the 3rd land (115) is less than the circle diameter of first land (113) D1。

5. the ladder drilling reamer according to claim 4 for being used to process aircraft skin rivet hole, it is characterised in that：The rank Terraced angle (13) is knife face structures after more, and the adjoiner of the ladder angle (13) and second chip space (32) is equipped with being arc-shaped Vibration damping land (14), the relief angle of the vibration damping land (14) is 2 °~5 °, the width d of the vibration damping land (14) for 0.05~ 0.1mm。

6. the ladder drilling reamer according to claim 5 for being used to process aircraft skin rivet hole, it is characterised in that：Two institutes To state and chip-breaker (15) is respectively equipped with ladder angle (13), one of them described ladder angle (13) is equipped with a chip-breaker (15), Another described ladder angle (13) is equipped with two chip-breakers (15).