A machine tool device for boring a thin-walled deep-hole part

Abstract

The application discloses a machine tool device for boring processing of a thin-wall deep-hole part, which comprises a cutter bar supporting seat, a cutter holder and a boring cutter; the boring cutter comprises a guide rod, a boring cutter head mounting seat and a cutter bar; a linear bearing is arranged in the cutter bar supporting seat; when boring, one end of the guide rod moves in the linear bearing, the other end of the guide rod is connected with one end of the boring cutter head mounting seat, the other end of the boring cutter head mounting seat is connected with one end of the cutter bar, and the other end of the cutter bar is connected with the cutter holder; one positive boring cutter head and one reverse boring cutter head are mounted on the boring cutter head mounting seat; the two boring cutter heads cut simultaneously, and the radial cutting forces generated when the two boring cutter heads cut are offset to each other. The application solves the problems of insufficient rigidity of the boring cutter bar, severe vibration and tool retraction in the boring processing of the thin-wall deep-hole part.

Description

Technical Field

[0001] This invention relates to the field of lathe cutting technology, and in particular to a machine tool apparatus for boring thin-walled deep-hole parts. Background Technology

[0002] In lathe machining, machining thin-walled deep holes is a challenging process (such as...). Figure 1 As shown in the image, these types of parts have long inner holes and require high surface roughness. Due to the slender and long shank of the boring tool, poor rigidity, and difficulty in cooling, the cuttings are not easily discharged. Furthermore, because the tool cuts inside the workpiece, tool wear and tool tip damage cannot be observed. Therefore, conventional machining methods are difficult to guarantee the requirements, or even impossible to perform the machining. Summary of the Invention

[0003] The main objective of this invention is to provide a machine tool device for boring thin-walled deep-hole parts, which aims to solve the problems of insufficient rigidity of the boring bar, severe vibration and tool deflection in the boring of thin-walled deep-hole parts.

[0004] To achieve the above objectives, the present invention provides a machine tool apparatus for boring thin-walled deep-hole parts, including a tool holder support, a tool post, and a boring tool;

[0005] The boring tool includes a guide rod, a boring tool head mounting base, and a tool shank. A linear bearing is installed inside the tool shank support. During boring, one end of the guide rod moves within the linear bearing, and the other end of the guide rod is connected to one end of the boring tool head mounting base. The other end of the boring tool head mounting base is connected to one end of the tool shank, and the other end of the tool shank is connected to the tool holder. Two boring tools, one positive and one negative, are mounted on the boring tool head mounting base. The radial cutting forces generated by the two boring tools during simultaneous cutting cancel each other out.

[0006] A further technical solution of the present invention is that two support columns are provided on the boring tool mounting base near the two boring tools.

[0007] A further technical solution of the present invention is that the two ends of the boring tool mounting base are provided with internal threads, and the guide rod and the tool bar are threadedly connected to the boring tool mounting base.

[0008] A further technical solution of the present invention is that a center frame is provided at one end of the guide rod and / or the tool bar near the boring tool head mounting seat.

[0009] A further technical solution of the present invention is that the tool post is mounted on the lathe via a middle slide.

[0010] A further technical solution of the present invention is that the lathe is equipped with a high-pressure cooling pump, and the coolant in the high-pressure cooling pump enters the inner hole of the tool bar through a water pipe connected to the tool bar.

[0011] A further technical solution of the present invention is that the principal cutting edge angle of the two boring cutters is controlled between 75° and 93°.

[0012] A further technical solution of the present invention is that the radius R of the two boring cutters is less than 0.3, and the width of the chamfer is half of the cutting depth.

[0013] A further technical solution of the present invention is that the rake angle of the two boring cutters is between 15° and 30°.

[0014] A further technical solution of the present invention is that the front of the two boring cutters is ground with a chip breaking groove with a radius R of 1.5-3, and the cutting edge inclination angle of the two boring cutters is between -3° and -10°.

[0015] The beneficial effects of the machine tool device for boring thin-walled deep-hole parts according to the present invention are as follows: The present invention, through the above technical solution, includes a tool holder support, a tool post, and a boring tool; the boring tool includes a guide rod, a boring tool head mounting seat, and a tool holder; a linear bearing is provided in the tool holder support; during boring, one end of the guide rod moves within the linear bearing, and the other end of the guide rod is connected to one end of the boring tool head mounting seat; the other end of the boring tool head mounting seat is connected to one end of the tool holder, and the other end of the tool holder is connected to the tool post; two boring tools, one positive and one negative, are mounted on the boring tool head mounting seat; the two boring tools cut simultaneously, and the radial cutting forces generated by the two boring tools during cutting cancel each other out, thus solving the problems of insufficient rigidity of the boring tool holder, severe vibration, and tool deflection in the boring of thin-walled deep-hole parts. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of thin-walled deep-hole parts in the prior art;

[0018] Figure 2 This is a schematic diagram of a preferred embodiment of the machine tool device for boring thin-walled deep-hole parts according to the present invention;

[0019] Figure 3 This is a schematic diagram of the tool holder support.

[0020] Figure 4 This is a schematic diagram of the boring tool head mounting base;

[0021] Figure 5 This is a structural diagram of the guide rod;

[0022] Figure 6 This is a schematic diagram of the tool holder structure;

[0023] Figure 7 This is a schematic diagram of the structure of the center frame and boring tool;

[0024] Figure 8 This is another structural schematic diagram of a preferred embodiment of the machine tool device for boring thin-walled deep-hole parts according to the present invention;

[0025] Explanation of icon numbers:

[0026] Tool holder support 10:

[0027] Linear bearing 101; Chuck 102; Morse taper 103; Spacer 104; Rolling bearing 105; Rolling bearing 106; Sleeve 107; Inner snap ring 108; Outer snap ring 109; Lathe spindle 110;

[0028] Knife Holder 20:

[0029] 201 middle slide plate; 202 cooling water pipe;

[0030] Boring tool 30:

[0031] Guide rod 301; boring head 302; boring head mounting base 304; tool bar 303; fixing nut 305; support column 306; fixing screw 307; center frame 308.

[0032] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0034] This invention designs and manufactures a special deep hole machining device. It employs a support point within the headstock spindle hole and utilizes linear bearings and support positioning techniques for machining. This solves the problems of insufficient rigidity of the boring bar, severe vibration, and tool deflection in deep hole machining, achieving excellent machining results. Now, according to... Figure 1 The workpiece is used to describe the device design and machining process for boring thin-walled deep-hole parts.

[0035] Please refer to Figures 2 to 8 The preferred embodiment of the machine tool device for boring thin-walled deep-hole parts of the present invention includes a tool holder support 10, a tool holder 20, and a boring tool 30.

[0036] The boring tool 30 includes a guide rod, a boring tool head mounting base 304, and a tool shank 303. A linear bearing 101 is provided inside the tool shank support 10. During boring, one end of the guide rod moves within the linear bearing 101, and the other end of the guide rod is connected to one end of the boring tool head mounting base 304. The other end of the boring tool head mounting base 304 is connected to one end of the tool shank 303, and the other end of the tool shank 303 is connected to the tool holder 20. Two boring tools 302, one positive and one negative, are mounted on the boring tool head mounting base 304 by a fixing nut 307.

[0037] In this embodiment, two support columns 306 are provided on the boring tool mounting base 304 near the two boring tools 302 by fixing nuts 305.

[0038] The boring tool mounting base 304 has internal threads at both ends, and the guide rod and tool bar 303 are threadedly connected to the boring tool mounting base 304.

[0039] A center frame 308 is provided at one end of the tool holder 303 near the boring tool head mounting seat 304.

[0040] The tool holder 20 is mounted on the lathe via the middle slide 201.

[0041] The lathe is equipped with a high-pressure cooling pump, and the coolant in the high-pressure cooling pump enters the inner hole of the tool holder 203 through a water pipe connected to the tool holder 203.

[0042] In this embodiment, the principal cutting angle of the two boring cutter heads 302 is controlled between 75° and 93°.

[0043] In this embodiment, the radius R of the two boring cutter heads 302 is less than 0.3, and the width of the chamfer is half of the cutting depth.

[0044] In this embodiment, the rake angle of the two boring cutter heads 302 is between 15° and 30°.

[0045] In this embodiment, the front of the two boring cutter heads 302 is ground with chip breaking grooves with a radius R of 1.5-3, and the cutting edge inclination angle of the two boring cutter heads 302 is between -3° and -10°.

[0046] The following combination Figures 2 to 8 The structure and working principle of the machine tool device for boring thin-walled deep-hole parts according to the present invention are described in detail.

[0047] I. Design, fabrication, and assembly of the 30mm boring bar:

[0048] Because the existing boring bar is relatively long, with an extension length of only over 2000 mm, it needs to be divided into two sections: a guide rod and a tool shank 303, connected by a threaded connection. The guide rod, approximately 900 mm long, serves as a guide and support, moving within the linear bearing 101 of the support seat inside the lathe spindle 110 during boring, increasing the rigidity of the tool shank 303. The guide rod must be straight and smooth, and can be made from standard precision steel bars. The other end of the tool shank 303 is mounted on the lathe's tool post 20. To prevent the boring head 302 from vibrating up and down during machining, two support pillars 306 welded from cemented carbide are added near the boring head 302 on the tool shank 303, serving to support and press the hole, improving the surface finish.

[0049] The boring tool mounting base 304 is for mounting the boring tool 30. It has mounting holes for the boring tool heads 302, and internal threads at both ends for connecting the guide rod 301 and the tool holder 303. Two boring tool heads 302, one positive and one negative, are installed in the mounting holes. The extension length of the boring tool heads 302 can be adjusted according to the size of the hole to be machined. The simultaneous cutting by the two boring tool heads 302 cancels out the radial cutting forces generated during cutting, ensuring the rigidity of the boring tool heads 302 and reducing tool deflection. Figure 2 , 4 As shown in Figures 5 and 6.

[0050] II. Design, fabrication, and assembly of the tool holder support 10:

[0051] In this embodiment, the tool holder support 10 includes a chuck 102, a Morse taper 103, a spacer 104, a rolling bearing 105, a rolling bearing 106, a linear bearing 101, a sleeve 107, an inner snap ring 108, and an outer snap ring 109. The specific design, manufacturing, and assembly process is as follows.

[0052] 1. First, use 45# round steel to machine the outer cone of the Morse taper seat. The surface roughness of the outer cone should be less than Ra1.6 to match the Morse inner taper hole of the lathe spindle 110. Remove the chuck 102 and insert the machined Morse taper seat into the Morse inner hole of the lathe spindle 110.

[0053] 2. Drill a through hole in the Morse taper seat and turn the through hole to... Then machine out a diameter of A stepped hole and a retaining ring groove, each 64 mm long. The distance from the center of the retaining ring groove to the step is equal to the center distance between the two outer retaining ring grooves on the linear bearing 101, used to install two radial ball bearings 105 to complete the machining of the Morse taper seat. (The size and depth of the stepped hole can be determined by determining the diameter of the tool holder 303 based on the diameter of the machined hole, and then selecting the outer diameter of the required ball bearing 105).

[0054] 3. When assembling the tool holder support 10, first install the two ball bearings 105 and the spacer 104 onto the outer diameter of the linear bearing 101, and fix them with the two external snap rings 109. Then, press the two rolling bearings 106 into the stepped holes machined in the Morse taper seat, install the internal snap rings 108, and complete the installation of the tool holder support. Figure 3 As shown.

[0055] III. Installation of the workpiece and boring tool 30

[0056] 1. Workpiece installation: One end of the workpiece is clamped on the lathe chuck 102, and the other end is clamped in the center rest 308 on the lathe guide rail. The workpiece rotates together with the chuck 102.

[0057] 2. Installation of the boring bar 30: The guide rod end of the boring bar 30 extends into the lathe spindle 110 hole and is installed into the linear bearing 101 hole of the tool holder support 10. The square end is installed on the tool post 20 of the middle slide 201 and fixed with the tool post 20 screws. When installing the tool post 303, it is necessary to ensure that the center line of the tool post 303 is concentric with the center line of the lathe spindle 110. When the slide box drives the tool post 20 to move, the guide rod must move smoothly and run stably within the linear bearing 101 hole of the support device. The boring bar 30 head is installed in the middle of the boring bar head mounting seat 304. During machining, the extension length of the boring bar head 302 can be adjusted to perform boring. To increase the rigidity of the tool holder 203, two support pillars 306 are located near the boring head 302. The tops of the support pillars 306 are welded with cemented carbide. This not only increases the rigidity of the tool holder 203, preventing tool deflection and vibration during boring and ensuring smooth cutting, but also allows for grinding of the machined inner hole surface, improving the surface quality. The tool holder 203 has a 10mm diameter through hole drilled in its axial direction. The inner hole at the end of the tool holder 303, mounted on the tool post 20, is connected to the lathe's cooling water pipe 202 for adding high-pressure coolant to flush away chips and cool and lubricate the boring tool 30. Figure 2 , Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8 As shown.

[0058] IV. Machining Principle of Thin-Walled Deep-Hole Parts:

[0059] 1. Machining the outer diameter of the workpiece: To complete Figure 1The workpiece shown must be machined first, including its outer diameter. To machine the outer diameter, first fit the machined plug with the center hole into one end of the tube blank. Use a clamping method with one ejector and one clamp to machine the outer diameter of the tube to the required size. Then, using the outer diameter as a reference, install and adjust the center rest 308 jaws, and then remove the ejector pin. This ensures that the workpiece's axis is concentric with the spindle, facilitating subsequent boring.

[0060] 2. Installation and Adjustment of the Boring Tool 30: When installing the tool holder 303, it is essential to ensure that the centerline of the tool holder 303 is concentric with the centerline of the lathe spindle 110. When moving the tool post 20, the guide rod should move smoothly within the linear bearing 101 hole of the lathe spindle 110. After installing the tool holder 203, adjust the stopper of the intermediate slide 201 to fix it in place, preventing it from moving during boring. The boring tool head mounting seat 304 is equipped with two boring tool heads 302, allowing for simultaneous left and right cutting. During machining, the extension length of the boring tool head 302 can be adjusted according to the diameter of the deep hole to be machined.

[0061] To ensure smooth machining of the boring head 302 and increase the rigidity of the tool holder 303, at the beginning of boring, the guide support column 306 on the tool holder 303 has not yet entered the hole and is not yet providing support. To enhance the rigidity of the tool holder 303 and ensure smooth boring, a center rest 309 is installed near the rear of the support column 306 to support the tool holder 303 and increase its rigidity. When the tool holder support column 306 is fully inserted into the hole, the machine is stopped and the support column 306 is adjusted so that both the upper and lower support columns 306 are in contact with the machined inner hole surface. Then, the fixing nut 305 is tightened, the center rest 309 on the tool holder 303 is removed, and the machine is restarted for boring. Figure 6 , Figure 8 As shown.

[0062] To reduce the cutting heat generated during boring and the wear of the boring tool 302, and to ensure smooth chip removal, the lathe's high-pressure cooling pump needs to be turned on. This allows coolant to enter the inner hole of the tool shank 303 through a water pipe connected to the tool shank 303, generating pressure to flush away chips and cool and lubricate the boring tool 30. Figure 2 , Figure 8 As shown.

[0063] 3. Selecting a Reasonable Tool Angle: Due to the relatively long extension length and poor rigidity of the tool holder 303 during machining, it is essential to select a reasonable tool angle to effectively reduce tool deflection and vibration, thus producing a qualified internal hole. The following points should be considered when selecting the angle: 1) To reduce radial cutting force and control tool deflection and vibration, the principal cutting edge angle of the boring tool 302 should be controlled between 75° and 93°. The tool tip radius should be small (R < 0.3), and the chamfer width should also be small, taking half of the feed rate. 2) To reduce cutting force, a larger rake angle should be selected, between 15° and 30°. 3) To ensure chip curling and breaking, a chip breaker groove with a radius of R1.5-3 should be ground on the front of the boring tool 302. A negative rake angle, between -3° and -10°, should be selected to direct the chips towards the machined surface and reduce cutting force.

[0064] 4. Select appropriate cutting parameters and turning methods: Since the part is clamped using a center rest 308, the workpiece rotation speed should not be too high, generally around 300 revolutions per minute. To reduce the friction between the workpiece and the chuck, a center rest 308 with rolling bearings 106 mounted on the front end of the chuck is used. Two boring tools 302 are used for cutting. The extension length of the tool heads should be adjusted reasonably according to the allowance of the blank to ensure that the depth of cut of both boring tools 302 is equal. The depth of cut of each boring tool 302 should be controlled below 2 mm, and the feed rate should be between 0.10-0.25 mm / revolution.

[0065] The beneficial effects of the machine tool device for boring thin-walled deep-hole parts according to the present invention are as follows: The present invention, through the above technical solution, includes a tool holder support, a tool post, and a boring tool; the boring tool includes a guide rod, a boring tool head mounting seat, and a tool holder; a linear bearing is provided in the tool holder support; during boring, one end of the guide rod moves within the linear bearing, and the other end of the guide rod is connected to one end of the boring tool head mounting seat; the other end of the boring tool head mounting seat is connected to one end of the tool holder, and the other end of the tool holder is connected to the tool post; two boring tools, one positive and one negative, are mounted on the boring tool head mounting seat; the two boring tools cut simultaneously, and the radial cutting forces generated by the two boring tools during cutting cancel each other out, thus solving the problems of insufficient rigidity of the boring tool holder, severe vibration, and tool deflection in the boring of thin-walled deep-hole parts.

[0066] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made under the concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A machine tool apparatus for boring thin-walled deep-hole parts, characterized in that, Includes tool holder support, tool post, and boring tool; The boring tool includes a guide rod, a boring tool head mounting base, and a tool shank. The tool shank support base includes a chuck, a Morse taper, a spacer, two rolling bearings, a linear bearing, a sleeve, an inner snap ring, and an outer snap ring. The Morse taper is inserted into the Morse taper bore at the lathe spindle end. The Morse taper contains two rolling bearings and one linear bearing, with the linear bearing installed in the inner bore of the rolling bearing. During boring, one end of the guide rod moves within the linear bearing, and the other end of the guide rod is connected to one end of the boring tool head mounting base. The other end of the boring tool head mounting base is connected to one end of the tool shank, and the other end of the tool shank is connected to the tool holder. The boring tool head mounting base is equipped with two boring tools, one positive and one negative. The radial cutting forces generated by the two boring tools during simultaneous cutting cancel each other out. The principal cutting edge angle of the two boring cutters is controlled between 75° and 93°; The radius R of the two boring cutters is less than 0.3, and the width of the chamfer is half of the cutting depth. The rake angle of the two boring cutters is between 15° and 30°; The two boring tools have chip breaking grooves with a radius R of 1.5-3 on their front sides, and the cutting edge inclination angle of the two boring tools is between -3° and -10°.

2. The machine tool apparatus for boring thin-walled deep-hole parts according to claim 1, characterized in that, The boring tool mounting base has two support columns near the two boring tools.

3. The machine tool apparatus for boring thin-walled deep-hole parts according to claim 1, characterized in that, The boring tool mounting base has internal threads at both ends, and the guide rod and tool bar are threadedly connected to the boring tool mounting base.

4. The machine tool apparatus for boring thin-walled deep-hole parts according to claim 1, characterized in that, A center frame is provided at one end of the guide rod and / or the tool bar near the boring tool head mounting seat.

5. The machine tool apparatus for boring thin-walled deep-hole parts according to claim 1, characterized in that, The tool post is mounted on the lathe via a middle slide.

6. The machine tool apparatus for boring thin-walled deep-hole parts according to claim 5, characterized in that, The lathe is equipped with a high-pressure cooling pump, and the coolant in the high-pressure cooling pump enters the inner hole of the tool holder through a water pipe connected to the tool holder.

Images