Method for eccentric chip breaking, main shaft with adjustable center of rotation and machining apparatus

Abstract

The application belongs to the technical field of automatic mechanical processing and relates to an eccentric chip breaking processing method, a main shaft with adjustable rotary center and a processing equipment. The key of the application is that the main shaft comprises an outer shaft, an inner shaft sleeved in the outer shaft, an adjusting assembly slidingly connected between the outer shaft and the inner shaft and an electric cylinder fixedly installed at one end of the outer shaft. Through the sleeve shaft design of the outer shaft and the inner shaft, the inclined engagement of the adjusting assembly and the displacement inclined slot in the outer shaft and the axial sliding of the adjusting assembly under the action of the electric cylinder, the offset of the center of the inner shaft relative to the center of the outer shaft is realized, that is, the rotary center of the main shaft is adjustable, and then the turning chip breaking processing is realized. In the process of adjusting the rotary center, the workpiece does not need to be clamped again, the automation requirement of the processing equipment can be better met, and the processing equipment can be better combined with the numerical control machine tool.

Description

Technical Field

[0001] This invention belongs to the field of automated machining technology, and relates to an eccentric chip breaking machining method, a spindle with adjustable rotation center, and machining equipment. Background Technology

[0002] With the rise of automated machining technology, chip breaking has become an indispensable machining technique. Currently, the main chip breaking methods are milling and program-controlled oscillation chip breaking. Milling suffers from low efficiency, while program-controlled oscillation chip breaking is limited to roughing due to rapid tool wear.

[0003] In the machining of round parts, turning has advantages such as high machining efficiency, long tool life and wide application range, but it has disadvantages such as difficulty in chip breaking. At the same time, milling and oscillating machining have low chip breaking efficiency, and oscillating chip breaking cannot be achieved in the machining of tapered threads, which makes it difficult for automated machining technology to be widely promoted and applied. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide an eccentric chip breaking machining method, a spindle with an adjustable rotation center and machining equipment, which, by continuously adjusting the offset between the workpiece rotation center and the workpiece center, forms a periodic change in the circumferential cutting depth, thereby forming a periodic chip breaking machining process, and providing technical support for automated machining.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A spindle with an adjustable rotation center includes an outer shaft, an inner shaft sleeved in the outer shaft, an adjustment assembly slidably connected between the outer shaft and the inner shaft, and an electric cylinder fixedly installed at one end of the outer shaft. The inner cavity of the outer shaft has a displacement groove that is axially slidably connected to the adjustment assembly and an inner shaft guide groove for circumferentially fixing the inner shaft.

[0007] An inclined wedge and a support surface matching the displacement inclined groove and the inner shaft guide groove are provided on the outer side of the inner shaft, and the displacement inclined groove and the inclined wedge are connected by an adjustment component.

[0008] The adjustment assembly includes a connecting block and a wedge mounted on the connecting block. The wedge is used to slide between the displacement groove and the wedge groove, and slides axially between the displacement groove and the wedge groove through the wedge, so that the inner shaft center is radially offset relative to the outer shaft center.

[0009] The connecting block is provided with a screw hole for threaded connection of the output shaft of the electric cylinder, so as to form a ball screw structure with the output shaft of the electric cylinder, thereby driving the adjusting component to slide along the axial direction of the inner shaft through the electric cylinder.

[0010] Furthermore, a through hole is provided on the inner shaft to serve as a clearance hole for the output shaft of the electric cylinder.

[0011] Furthermore, the displacement groove is composed of two parallel grooves, the inner shaft guide groove is composed of two parallel planar guide grooves, and the plane where the displacement groove is located and the plane where the inner shaft guide groove is located are arranged adjacent to each other in the outer shaft cavity.

[0012] Furthermore, the wedge includes two parallel wedges, a first wedge and a second wedge, which correspond to two parallel grooves in the displacement groove, respectively.

[0013] Furthermore, a chuck is provided at the end of the inner shaft away from the electric cylinder to clamp the workpiece.

[0014] Furthermore, a support step is arranged at the end of the inner shaft near the chuck along the length direction, and the support step is in contact with the end of the outer shaft near the chuck to serve as an axial limiting device for the inner shaft.

[0015] The present invention also provides a machining device with an adjustable rotation center, including a bed, a spindle box, a spindle, a slide assembly, and a tool post. The spindle box is fixedly installed at one end of the bed, the spindle is installed in the spindle box and powered by the spindle box, the slide assembly is slidably installed on the bed along the length of the bed and is arranged opposite to the spindle box, and the tool post is arranged on the slide assembly. The spindle is characterized in that: the spindle is the aforementioned adjustable rotation center spindle, and the spindle box is drivenly connected to the outer shaft of the spindle to drive the outer shaft to rotate, and a chuck is provided at the end of the inner shaft of the spindle away from the electric cylinder to clamp the workpiece.

[0016] This invention also provides an eccentric chip breaking machining method, and provides the aforementioned machining equipment with an adjustable rotation center, specifically including the following steps:

[0017] Step 1. Preparation before operation: Install the workpiece blank onto the chuck, ensuring that the center of the workpiece blank coincides with the center of the chuck. Adjust the electric cylinder to make the outer shaft and inner shaft concentric. Install the tool on the tool post.

[0018] Step 2. Machining of the workpiece blank;

[0019] S1. Set an even number of machining passes based on the machining allowance of the workpiece blank;

[0020] S2. Based on the single machining allowance, set the eccentricity of the inner shaft center relative to the outer shaft center, thereby achieving the purpose of adjusting the eccentricity between the center of the workpiece and the rotation center of the spindle.

[0021] S3. Adjust the center of the inner shaft by sliding the electric cylinder drive adjustment component along the axial direction of the inner shaft and moving the axial position of the adjustment component according to the set eccentricity.

[0022] S4. The spindle box drives the outer spindle to rotate, which in turn drives the workpiece blank to rotate through the inner spindle and chuck. The slide assembly drives the tool to move axially through the tool post, completing one pass of machining of the workpiece blank.

[0023] S5. Adjust the electric cylinder to offset the inner shaft center from the inner shaft center of the previous pass;

[0024] S6. Repeat step S4 to complete the second processing pass;

[0025] S7. Repeat steps S4 to S6 to complete the last pass of processing of the workpiece blank and obtain the finished workpiece.

[0026] Furthermore, during the last or second pass, the inner shaft center is aligned with the outer shaft center by adjusting the electric cylinder.

[0027] Furthermore, let the maximum adjustment eccentricity of the inner shaft center in the machining equipment with adjustable rotation center be E, and let the difference in wall thickness of the circumferential iron chip particles in the workpiece blank be e, and e≤E.

[0028] The beneficial effects of this invention are as follows:

[0029] The present invention provides an eccentric chip breaking machining method, a spindle with adjustable rotation center, and machining equipment. The key feature is the spindle with adjustable rotation center. This spindle achieves the offset of the inner spindle center relative to the outer spindle center through a sleeve design of an outer spindle and an inner spindle, the wedge of the adjusting component and the displacement groove in the outer spindle, and the axial sliding of the adjusting component under the action of an electric cylinder. This achieves the adjustable rotation center of the spindle, thereby realizing chip breaking machining during turning. Furthermore, the adjustment of the rotation center does not require secondary clamping of the workpiece, which can better meet the automation requirements of the machining equipment and can be better integrated with CNC machine tools.

[0030] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0031] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0032] Figure 1 This is a schematic diagram of the structure of a processing device with an adjustable workpiece rotation center according to the present invention;

[0033] Figure 2 This is a three-dimensional structural diagram of the spindle in this invention;

[0034] Figure 3 This is a schematic diagram of the main shaft in this invention;

[0035] Figure 4 This is a schematic diagram of the structure of the outer shaft in this invention;

[0036] Figure 5 for Figure 4 AA section view in the middle;

[0037] Figure 6 This is a schematic diagram of the structure of the adjustment component in this invention;

[0038] Figure 7 This is the front view of the adjustment component in this invention;

[0039] Figure 8 This is a schematic diagram of the inner shaft structure in this invention;

[0040] Figure 9 This is the front view of the inner shaft in this invention;

[0041] Figure 10 This is a schematic diagram of the workpiece blank;

[0042] Figure 11 This is a schematic diagram of the machining process for the workpiece blank.

[0043] Figure 12 for Figure 11 BB cross-section diagram;

[0044] Figure 13 This is a schematic diagram of the finished workpiece.

[0045] Reference numerals: Bed 1, Spindle box 2, Spindle 3, Electric cylinder 31, Outer spindle 32, Bearing step 321, Displacement groove 322, Inner spindle guide groove 323, Connecting screw hole 324, Adjustment assembly 33, First wedge 331, Second wedge 332, Connecting block 333, Screw hole 3331, Inner spindle 34, Through hole 341, Wedge groove 342, Support surface 343, Support step 344, Connecting thread 345, Chuck 35, Slide assembly 4, Tool post 5, Workpiece blank 6, First machining allowance 7, Second machining allowance 8, Third machining allowance 9, Fourth machining allowance 10, Finished workpiece 11. Detailed Implementation

[0046] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0047] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0048] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0049] Please see Figures 1-9 This is a machining equipment with an adjustable rotation center, including a bed 1, a spindle box 2, a spindle 3, a slide assembly 4, and a tool post 5. The bed 1 provides support for the equipment and provides related power. The spindle box 2 is mounted on the bed 1 and converts the power into the motion and load required by the spindle 3. The spindle 3 is mounted in the spindle box 3 and is used to transmit the motion and load from the spindle box 2, clamp the workpiece, and realize the rotation of the workpiece. The slide assembly 4 can move on the guide rail in the bed 1 to complete the movement of the tool post 5. The tool post 5 is mounted on the slide assembly 4 and can move longitudinally along the guide rail perpendicular to the bed 1, or move with the slide assembly 4 to complete the machining of the workpiece.

[0050] The key feature of this embodiment is that the main shaft 3 includes an outer shaft 32, an inner shaft 34 sleeved in the outer shaft 32, an adjustment assembly 33 arranged between the outer shaft 32 and the inner shaft 34, and an electric cylinder 31 fixedly installed at one end of the outer shaft 32, and a chuck 35 is connected to the end of the inner shaft 34 away from the electric cylinder 31.

[0051] Specifically, the electric cylinder 31 is fixedly connected to the outer shaft 32, and the output shaft of the electric cylinder 31 is threadedly connected to the adjusting component 33 to form a ball screw structure, thereby driving the adjusting component 33 to move back and forth.

[0052] The outer shaft 32 is connected to the power output structure in the spindle box 2. Driven by the power of the spindle box 2, it rotates around the center of the outer shaft 32, transmitting cutting loads and supporting the inner shaft 34. The outer shaft 32 has a bearing step 321 on its outer side for connecting with the bearing in the spindle box 2. The inner cavity of the outer shaft 32 has a displacement groove 322, which consists of two parallel grooves and is used to cooperate with the adjustment component 33 to achieve radial offset of the inner shaft 34. The inner cavity of the outer shaft 32 also has an inner shaft guide groove 323, which cooperates with the two sides of the inner shaft 34 adjacent to the displacement groove 322 to transmit loads. Figure 4 As shown, the displacement grooves 322 are located on the upper and lower sides of the inner cavity of the outer shaft 32, respectively, and are used to connect the adjustment components. The inner shaft guide grooves 323 are located on the left and right sides of the inner cavity of the outer shaft 32, and are used to circumferentially fix the outer shaft and the inner shaft, thereby transmitting loads.

[0053] In other embodiments, the displacement groove and the inner shaft guide groove can be configured as one, rather than two.

[0054] Specifically, a connecting screw hole 324 is provided at the end of the outer shaft 32 away from the chuck 35, which serves as a mounting screw hole for the electric cylinder 31.

[0055] The adjustment component 33 includes a connecting block 333 and a first wedge 331 and a second wedge 332 connected by the connecting block 333 and parallel to each other. The first wedge 331 and the second wedge 332 correspond to two parallel wedges in the displacement groove 322, and the connecting block 333 is connected to the first wedge 331 and the second wedge 332 by a T-slot. The connecting block 333 is provided with a screw hole 3331 for connecting the output shaft of the electric cylinder to form a ball screw structure.

[0056] Under the action of the output shaft in the electric cylinder 31, the adjustment component 33 is driven to move along the axial direction of the inner shaft 34 through the ball screw structure. The radial eccentricity of the inner shaft 34 is achieved by using the first wedge 331 and the second wedge 332 in conjunction with the displacement groove 322.

[0057] The inner shaft 34 has a through hole 341, a wedge groove 342, a support surface 343, a support step 344, and a connecting thread 345. The through hole 341 is arranged in the middle of the inner shaft in the vertical direction and along the axis to serve as a clearance hole for the output shaft in the electric cylinder 31, and can also serve as a through hole for slender workpieces. The wedge groove 342 includes two opposing guide grooves for cooperating with the first wedge 331 and the second wedge 332 in the adjustment assembly 33. The support surface 343 is used to cooperate with the inner shaft guide groove 323 on the outer shaft, and the wedge groove 342 and the support surface 343 are arranged adjacent to each other on the outer side of the inner shaft.

[0058] The support step 344 is arranged at one end of the inner shaft near the chuck along the length direction, and the outer diameter of the support step 344 is larger than the inner diameter of the outer shaft 32. It abuts against the end of the outer shaft 32 near the chuck 35, serving as an axial limiting device to prevent axial movement between the outer shaft 32 and the inner shaft 34. The connecting thread 345 is arranged on the outside of the inner shaft and located on the side of the support step 344 away from the outer shaft, for connection with the chuck 35.

[0059] The inner shaft 34 is indirectly connected to the outer shaft 32 through the wedge groove 342 and the adjusting component 33, and is directly connected to the outer shaft through the support surface 343. It does not produce axial movement or relative rotation with the outer shaft 32. At the same time, it is connected to the chuck 35 through the connecting thread 345 to transfer the load from the outer shaft 32 to the chuck. Through the axial movement of the adjusting component 33 on the outside of the inner shaft, and in conjunction with the cooperation of the displacement wedge groove 322 with the first wedge 331 and the second wedge 332, the radial offset of the inner shaft 34 relative to the outer shaft 32 is realized.

[0060] The spindle 3 drives the adjustment assembly 33 to move back and forth via the electric cylinder 31 connected to the outer spindle 32, thereby causing the rotation center of the inner spindle 34 to shift radially relative to the rotation center of the outer spindle 32. This causes the rotation center of the chuck 35 connected to the inner spindle 34 to shift radially relative to the rotation center of the outer spindle, which in turn causes the center of the workpiece to shift radially relative to the rotation center of the outer spindle. This achieves a change in the radial cutting depth during rotary cutting, thereby enabling chip breaking of the workpiece.

[0061] The operating principle of the machining equipment with this adjustable rotary center is as follows:

[0062] 1) Preparations before the assignment:

[0063] Install the workpiece blank 6 onto the chuck 35, ensuring that the center of the workpiece coincides with the center of the chuck. Adjust the electric cylinder 31 to make the outer shaft and inner shaft concentric, and then install the cutting tool.

[0064] 2) Workpiece blank processing;

[0065] (1) Set an even number of machining passes based on the machining allowance of the workpiece blank;

[0066] (2) Based on the single machining allowance, set the eccentricity of the inner shaft center relative to the outer shaft center, thereby achieving the purpose of adjusting the eccentricity between the center of the workpiece and the rotation center of the spindle.

[0067] (3) Adjust the electric cylinder 31 and adjust the axial position of the adjustment component according to the set eccentricity to adjust the inner shaft center;

[0068] (4) The spindle box 2 drives the outer shaft 32 to rotate, and then drives the workpiece blank to rotate through the inner shaft and chuck. The tool holder 5 drives the tool to move axially, completing one pass of workpiece blank processing.

[0069] (5) Adjust the electric cylinder 31 to make the inner shaft center offset from the inner shaft center of the previous pass. After the offset, it can coincide with the outer shaft center or not coincide with the outer shaft center.

[0070] (6) Repeat step 4 to complete the second processing step;

[0071] (7) Repeat steps 4 to 6 until the last processing pass is completed;

[0072] (8) Adjust the electric cylinder 31 to offset the inner shaft center from the previous inner shaft center, and make the offset inner shaft center coincide with the outer shaft center. Then, drive the outer shaft 32 to rotate through the spindle box 2, and then drive the workpiece blank to rotate through the inner shaft and chuck. The tool holder 5 drives the tool to move axially, and complete the last pass of workpiece blank processing to obtain the finished workpiece.

[0073] like Figures 10-13 As shown, in this embodiment, a total of 4 processing passes are set, with processing allowances of 7 for the first pass, 8 for the second pass, 9 for the third pass, and 10 for the fourth pass. After the workpiece blank 6 is processed through 4 passes, the finished workpiece is finally obtained.

[0074] Specifically, in this embodiment, the maximum adjustment eccentricity of the inner shaft center (i.e., the workpiece clamping center) in the machining equipment with adjustable rotation center is set to E. Based on the cutting principle, calculations or experiments are performed to ensure that the difference in wall thickness of the circumferential iron chips in the workpiece blank is e, and e≤E. This ensures that the eccentricity set for each machining pass can be within the maximum adjustment eccentricity E (i.e., it can be satisfied by adjusting the eccentricity of the inner shaft center).

[0075] Note: Depending on the machining accuracy requirements, the inner and outer axes must meet the concentricity requirements for the last or second machining operation. This technology can be combined with CNC programs. During workpiece rotation, the electric cylinder 31 is activated to continuously change the workpiece rotation center, thereby achieving machining with different depths of cut and meeting the requirements of chip breaking machining.

[0076] It should be noted that, in another embodiment, the spindle with adjustable rotation center can also be used in machining equipment where the tool rotates but the workpiece does not rotate, such as a boring machine.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A spindle with an adjustable rotation center, characterized in that: It includes an outer shaft, an inner shaft sleeved in the outer shaft, an adjustment assembly slidably connected between the outer shaft and the inner shaft, and an electric cylinder fixedly installed at one end of the outer shaft. The inner cavity of the outer shaft has a displacement groove that is axially slidably connected to the adjustment assembly and an inner shaft guide groove for circumferentially fixing the inner shaft. An inclined wedge and a support surface matching the displacement inclined groove and the inner shaft guide groove are provided on the outer side of the inner shaft, and the displacement inclined groove and the inclined wedge are connected by an adjustment component. The adjustment assembly includes a connecting block and a wedge mounted on the connecting block. The wedge is used to slide between the displacement groove and the wedge groove, and slides axially between the displacement groove and the wedge groove through the wedge, so that the inner shaft center is radially offset relative to the outer shaft center. The connecting block is provided with a screw hole for threaded connection of the output shaft of the electric cylinder, so as to form a ball screw structure with the output shaft of the electric cylinder, thereby driving the adjusting component to slide along the axial direction of the inner shaft through the electric cylinder. The displacement groove is composed of two parallel grooves, the inner shaft guide groove is composed of two parallel planar guide grooves, and the plane where the displacement groove is located and the plane where the inner shaft guide groove is located are arranged adjacent to each other in the outer shaft cavity; the wedge includes two parallel wedges, a first wedge and a second wedge, which correspond to the two parallel grooves in the displacement groove respectively.

2. The spindle with adjustable rotation center according to claim 1, characterized in that: A through hole is provided on the inner shaft to serve as a clearance hole for the output shaft of the electric cylinder.

3. The spindle with adjustable rotation center according to claim 1, characterized in that: A chuck is provided at the end of the inner shaft away from the electric cylinder to clamp the workpiece.

4. The spindle with adjustable rotation center according to claim 1, characterized in that: A support step is arranged at one end of the inner shaft near the chuck along the length direction, and the support step is in contact with the end of the outer shaft near the chuck to serve as an axial limiting device for the inner shaft.

5. A machining device with an adjustable rotation center, comprising a bed, a spindle head, a spindle, a slide assembly, and a tool post, wherein the spindle head is fixedly mounted on one end of the bed, the spindle is mounted in the spindle head and powered by the spindle head, the slide assembly is slidably mounted on the bed along the length of the bed and arranged opposite to the spindle head, and the tool post is arranged on the slide assembly, characterized in that: The spindle is an adjustable spindle according to any one of claims 1 to 4, and the spindle box is connected to the outer shaft of the spindle to drive the outer shaft to rotate, and a chuck is provided at the end of the inner shaft of the spindle away from the electric cylinder to clamp the workpiece.

6. An eccentric chip breaking machining method, characterized in that, Providing a machining equipment with an adjustable rotation center according to claim 5 specifically includes the following steps: Step 1. Preparation before operation: Install the workpiece blank onto the chuck, ensuring that the center of the workpiece blank coincides with the center of the chuck. Adjust the electric cylinder to make the outer shaft and inner shaft concentric. Install the tool on the tool holder. Step 2. Machining of the workpiece blank; S1. Set an even number of machining passes based on the machining allowance of the workpiece blank; S2. Based on the single machining allowance, set the eccentricity of the inner shaft center relative to the outer shaft center, thereby achieving the purpose of adjusting the eccentricity between the center of the workpiece and the rotation center of the spindle. S3. Adjust the center of the inner shaft by sliding the electric cylinder drive adjustment component along the axial direction of the inner shaft and moving the axial position of the adjustment component according to the set eccentricity. S4. The spindle box drives the outer spindle to rotate, which in turn drives the workpiece blank to rotate through the inner spindle and chuck. The slide assembly drives the tool to move axially through the tool post, completing one pass of machining of the workpiece blank. S5. Adjust the electric cylinder to offset the inner shaft center from the inner shaft center of the previous pass; S6. Repeat step S4 to complete the second processing pass; S7. Repeat steps S4 to S6 to complete the last pass of processing of the workpiece blank and obtain the finished workpiece.

7. The eccentric chip breaking method according to claim 6, characterized in that: During the last or second pass, the electric cylinder is adjusted to make the center of the inner shaft coincide with the center of the outer shaft.

8. The eccentric chip breaking method according to claim 6, characterized in that: Let E be the maximum adjustment eccentricity of the inner shaft center in the machining equipment with adjustable rotation center, and let e be the difference in wall thickness of the circumferential iron chip particles in the workpiece blank, where e≤E.

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