Positioning mechanism and method for shaft machining and application

Abstract

The positioning mechanism for shaft machining comprises a rack, V-shaped reference blocks arranged on the rack and used for supporting the two ends of a shaft workpiece, a reference positioning mechanism and a centering jacking mechanism, the reference positioning mechanism and the centering jacking mechanism are located at the two ends of the rack, and the heights of the two V-shaped reference blocks are consistent; the reference positioning mechanism comprises a reference air cylinder, a chuck connected to the extending end of the reference air cylinder and used for clamping the shaft side surface of the end of the shaft workpiece, and a first tip arranged in the center of the chuck. The centering and jacking mechanism is slidably connected to the rack through the stroke adjusting mechanism and comprises a jacking air cylinder and a second tip arranged at the extending end of the jacking air cylinder. According to the invention, the existing positioning mode of the shaft workpiece is optimized, so that the shaft workpiece has higher coaxiality in the machining process, and the higher clamping force of a chuck is not needed, so that the damage risk of the workpiece is obviously reduced, the current requirements of high-precision and rapid automatic machining production can be met, and the production efficiency is improved. And shaft workpieces with different specifications and characteristics can be flexibly processed.

Description

Technical Field

[0001] The present invention relates to the technical fields of machine tool positioning fixtures and shaft machining, and particularly to a positioning mechanism, method and application for shaft machining. Background Art

[0002] In the current machining process of shaft workpieces, precise positioning is a prerequisite for realizing automated machining operations. Among them, the importance of axial end positioning is self-evident. It is not only the cornerstone for ensuring the machining accuracy and surface quality of workpieces, but also a key factor related to the subsequent assembly efficiency and long-term operation stability of workpieces. Specifically, the end positioning mechanism of shaft workpieces aims to prevent the axial displacement of workpieces during the machining process, thereby maintaining the consistency and stability of their positions, which is decisive for ensuring machining accuracy and the smooth progress of the assembly process.

[0003] Taking the automotive manufacturing industry as an example, the end positioning accuracy of shaft components such as crankshafts and camshafts in engines is directly related to the power output efficiency and driving stability of vehicles. If there are deviations in end positioning, it will not only cause error accumulation during the machining process, but may also have a negative impact on the overall performance and service life of workpieces.

[0004] In the existing technical system, there are various types of end positioning mechanisms, including but not limited to thrust washers, shaft shoulder structures, and locking nuts. These mechanisms effectively limit the free movement of the shaft in the axial direction through diverse constraint methods, ensuring precise positioning of the end. However, the widely used three-jaw chuck clamping method has many limitations when positioning and supporting shaft workpieces. For example, the jaws may damage the crankshaft end face due to excessive pressure, and the wear of the clamping block on the shaft workpiece cannot be ignored. These factors will weaken the positioning accuracy between the workpiece and the tooling, and thus have an adverse impact on the machining quality.

[0005] In addition, when the three-jaw chuck clamps large-diameter workpieces, it is difficult to achieve precise centering of the workpiece, and its adjustment range is limited and the operation is inconvenient, which greatly restricts the types and specifications of workpieces it can accommodate.

[0006] Therefore, in the face of the diversity and complexity of the machining requirements of shaft workpieces, in order to ensure both high-precision positioning and effectively reduce damage to workpieces, the present invention proposes a positioning mechanism, method and application for shaft machining. Summary of the Invention

[0007] The object of the present invention is to solve the deficiencies existing in the prior art, and a positioning mechanism, method and application for shaft machining are proposed. It aims to overcome the deficiencies of the prior art. By optimizing the design of the positioning mechanism, it not only ensures the high-precision positioning of shaft workpieces during machining, but also significantly reduces the risk of damage to the workpieces, providing a more flexible and efficient solution for the machining of shaft workpieces with different specifications and characteristics.

[0008] To achieve the above object, the present invention provides the following technical solutions: A positioning mechanism for shaft machining, comprising a frame, V-shaped reference blocks arranged on the frame for supporting both ends of the shaft workpiece, and a reference positioning mechanism and a centering and clamping mechanism located at both ends of the frame. The heights of the two V-shaped reference blocks are the same; The reference positioning mechanism includes a reference cylinder, a chuck connected to the extended end of the reference cylinder and used for clamping the side surface of the end of the shaft workpiece, and a first center point provided at the center of the chuck; The centering and clamping mechanism is slidably connected to the frame through a stroke adjustment mechanism. The centering and clamping mechanism includes a clamping cylinder and a second center point provided at the extended end of the clamping cylinder; The first center point and the second center point are driven to clamp the tapered grooves at the centers of both end faces of the shaft workpiece.

[0009] Through the above structure, the existing positioning method for shaft workpieces is optimized, so that the shaft workpieces have higher coaxiality during machining, and there is no need for a high clamping force of the chuck, significantly reducing the risk of damage to the workpieces, meeting the requirements of current high-precision and fast automated machining production, and being able to flexibly respond when facing the machining of shaft workpieces with different specifications and characteristics.

[0010] Preferably, a reference slide rail is further provided on the base frame, and the chuck is slidably connected to the reference slide rail.

[0011] Through the above structure, it is ensured that the first center point and the chuck move smoothly to the reference point.

[0012] Preferably, the chuck is a floating jaw power chuck, and a flexible pad is provided on the inner side of the jaws in the chuck.

[0013] Through the above structure, the chuck is less likely to damage the surface of the shaft workpiece and is suitable for precision machining.

[0014] Preferably, the opening height of the two V-shaped reference blocks is: when the shaft workpiece is placed, the height of the tapered grooves at both ends of the shaft workpiece does not exceed the height of the first center point and the second center point.

[0015] Through the above structure, it is ensured that the positioning process of the present positioning mechanism can proceed smoothly without the need to operate the two V-shaped reference blocks to rise or fall.

[0016] Preferably, the stroke adjustment mechanism includes: A stroke guide rail, fixedly connected to the frame; A rack, fixedly connected to the frame; A base, slidably connected to the stroke guide rail, and the pressing cylinder is installed on the base; A speed reducer, fixedly installed on the base. A gear cooperating with the rack is provided at the output end of the speed reducer, and a handwheel is connected to the input end of the speed reducer; A locking member for locking the position of the base on the stroke guide rail.

[0017] With the above structure, it is possible to easily adjust the position of the centering and pressing mechanism in the length direction of the frame, so as to be compatible with shaft workpieces of different length specifications, and the compatibility of this positioning mechanism is improved.

[0018] Preferably, the locking member includes at least one of a screw, a positioning pin, etc.

[0019] Preferably, the pressing cylinder is installed on the base through a vertical frame, and the centering and pressing mechanism further includes: A pressing guide rail, fixedly connected to the base; A vertical plate, parallel to the vertical frame and slidably connected to the pressing guide rail; A mounting seat for rotatably mounting the second center and fixedly connected to one side of the vertical plate close to the reference positioning mechanism.

[0020] With the above structure, a specific sliding mode of the centering and pressing mechanism is provided, which can make the second center move smoothly and does not affect the rotation of the shaft workpiece during the machining process.

[0021] Preferably, an infrared opposed sensor for detecting the presence or absence of a shaft workpiece is further provided on the frame.

[0022] With the above structure, when a shaft workpiece to be machined is placed, this positioning mechanism can automatically generate an instruction, and then this positioning mechanism can automatically perform a positioning operation, with a high degree of automation, no need for manual operation, and is more convenient to use.

[0023] Preferably, a chip collecting hopper is further provided on the frame and located below the V-shaped reference block, and a waste collecting box is further provided at the bottom opening of the chip collecting hopper.

[0024] With the above structure, it is convenient to collect the waste chips generated during the machining of the shaft workpiece and convenient to take them away.

[0025] In order to achieve the above object, the present invention also provides the following technical solutions: A positioning method for shaft machining, which is applied to the above-mentioned positioning mechanism, includes the following steps: S1. Place the shaft workpiece on two V-shaped reference blocks, and the two V-shaped reference blocks respectively support both ends of the shaft workpiece; S2. Start the reference cylinder, and the first center point moves towards the shaft workpiece to the reference position; S3. Start the clamping cylinder, and the second center point moves towards the shaft workpiece, pushing the shaft workpiece so that both ends of the shaft workpiece are lifted and clamped by the second center point and the first center point; S5. Start the chuck to clamp the shaft side surface of the shaft workpiece.

[0026] Through the above method, centering positioning and origin finding can be completed simultaneously, and the damage to the shaft workpiece is relatively small, which can meet the requirements of current high-precision and fast automated processing production.

[0027] In order to achieve the above object, the present invention also provides the following technical solutions: A positioning mechanism for crankshaft machining, including the above-mentioned positioning mechanism, further includes an angular positioning mechanism, which is arranged on the frame and located between two V-shaped reference blocks. The angular positioning mechanism includes: A lifting mechanism, fixedly connected to the frame; A clamping mechanism, arranged at the output end of the lifting mechanism, and the clamping mechanism can clamp the crankshaft when it operates.

[0028] Through the above structure, radial positioning of the crankshaft is achieved with a relatively simple structure, and it can also be compatible with crankshafts of different length specifications, and the positioning accuracy is high, and the surface of the crankshaft is not easily damaged by the chuck during the machining process.

[0029] Preferably, the lifting mechanism includes a lifting cylinder, the clamping mechanism includes a clamping cylinder and two jaws arranged on the clamping cylinder, and the two jaws separate or approach each other when the clamping cylinder operates.

[0030] Through the above structure, precise radial positioning of the crankshaft is achieved with a relatively simple structure.

[0031] Preferably, it further includes a first auxiliary guide rail arranged on the frame, the lifting cylinder is slidably connected to the first auxiliary guide rail, and the lifting cylinder slides in the horizontal plane and the sliding direction is perpendicular to the length direction of the reference slide rail.

[0032] Through the above structure, on the basis of conveniently and quickly finding the radial zero point during crankshaft machining, an auxiliary holding force can be further provided for the radial angle of the crankshaft during the machining process, which neither requires the chuck to provide too large a clamping force to damage the surface of the crankshaft, nor worries about insufficient clamping force of the chuck causing the crankshaft to rotate during machining and affecting the machining accuracy.

[0033] Preferably, it further includes a second auxiliary guide rail provided on the frame. The first auxiliary guide rail is slidably connected to the second auxiliary guide rail, and the first auxiliary guide rail slides in the horizontal plane and the sliding direction is parallel to the length direction of the reference slide rail.

[0034] With the above structure, the angular positioning mechanism can replace the clamped segment, ensuring that each segment of the crankshaft can be machined and that each segment of the crankshaft has an auxiliary clamping force during the machining process to ensure the machining accuracy.

[0035] Preferably, it further includes a driving mechanism. The two driving mechanisms are respectively used to drive the lifting cylinder to slide on the first auxiliary guide rail and drive the first auxiliary guide rail to slide on the second auxiliary guide rail. The driving mechanism includes one of a screw and nut translation mechanism, a cylinder, a hydraulic cylinder, etc.

[0036] With the above structure, the operation of the entire angular positioning mechanism to provide clamping force during the machining process can be fully automated.

[0037] To achieve the above object, the present invention also provides the following technical solutions: A positioning method for crankshaft machining, applied to the positioning mechanism for crankshaft machining as described above, including the positioning method for shaft machining as described above. Before step S5, it further includes: S4. Start the lifting cylinder to drive the clamping mechanism to rise. After rising in place, start the clamping cylinder to clamp the segment of the crankshaft to achieve angular positioning of the crankshaft.

[0038] Through the above method, it can ensure the smooth progress of the positioning process of the crankshaft and ensure the accuracy during the machining process.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows: It optimizes the existing positioning method for shaft workpieces, making the shaft workpieces have higher coaxiality during the machining process, and without the need for a high clamping force of the chuck, significantly reducing the risk of damage to the workpiece, being able to meet the current requirements of high-precision and fast automated machining production, and being able to flexibly respond when facing the machining of shaft workpieces with different specifications and characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a three-dimensional assembly structure schematic diagram of the positioning mechanism for shaft machining proposed by the present invention; Figure 2 It is a top view of the structure of the positioning mechanism for shaft machining proposed by the present invention; Figure 3 It is a three-dimensional structure schematic diagram of the frame in the positioning mechanism for shaft machining proposed by the present invention, mainly showing the distribution positions of each mechanism on the frame; Figure 4 It is a schematic diagram of the three-dimensional structure of an existing shaft workpiece / crankshaft, mainly showing a tapered hole; Figure 5 This is a schematic diagram of the three-dimensional structure of the frame in the positioning mechanism for shaft processing proposed by the present invention, mainly showing the rack and travel guide rail; Figure 6 This is a schematic diagram of the three-dimensional structure of the V-shaped reference block in the positioning mechanism for shaft processing proposed by the present invention; Figure 7 This is a schematic diagram of the three-dimensional structure of the reference positioning mechanism in the positioning mechanism for shaft processing proposed by the present invention, mainly showing the position distribution of the first center and the chuck; Figure 8 This is a schematic diagram of the three-dimensional structure of the reference positioning mechanism in the positioning mechanism for shaft processing proposed by the present invention, mainly showing the reference guide rail; Figure 9 This is a schematic diagram of the three-dimensional structure of the centering and tightening mechanism in the positioning mechanism for shaft processing proposed by the present invention, mainly showing the second center; Figure 10 This is a schematic diagram of the three-dimensional structure of the centering and tightening mechanism in the positioning mechanism for shaft processing proposed by the present invention from another perspective, mainly showing the gears; Figure 11 This is a schematic diagram of the three-dimensional structure of the centering and tightening mechanism in the positioning mechanism for shaft processing proposed by the present invention, mainly showing the tightening cylinder; Figure 12 This is a schematic diagram of the three-dimensional structure of the angular positioning mechanism in the positioning mechanism for shaft processing proposed by the present invention; Figure 13 This is a structural front view of the angular positioning mechanism in the positioning mechanism for shaft processing proposed by the present invention.

[0041] In the picture: A. Shaft workpieces; A1. Tapered groove; a. Crankshaft; 1. Frame; 2. V-shaped reference block; 3. Reference positioning mechanism; 31. Reference cylinder; 32. Chuck; 33. First center; 34. Reference slide; 35. Motor; 4. Centering and tightening mechanism; 41. Stroke adjustment mechanism; 411. Stroke guide rail; 412. Rack; 413. Base; 414. Reducer; 415. Gear; 416. Handwheel; 417. Locking component; 42. Tightening cylinder; 43. Second centering center; 44. Stand; 45. Tightening guide rail; 46. Stand plate; 47. Mounting seat; 5. Infrared radiation sensor; 6. Angular positioning mechanism; 61. Lifting mechanism; 611. Lifting cylinder; 62. Clamping mechanism; 621. Clamping cylinder; 622. Claw; 63. First auxiliary guide rail; 64. Second auxiliary guide rail; 65. Driving mechanism; 7. Chip collecting hopper; 71. Scrap collecting box. Specific embodiments

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0043] Embodiment 1: Please refer to Figures 1-10 , the present invention provides the following technical solutions: A positioning mechanism for shaft machining, including a frame 1, V-shaped reference blocks 2 provided on the frame 1 for supporting both ends of the shaft workpiece A, and a reference positioning mechanism 3 and a centering and tightening mechanism 4 located at both ends of the frame 1. The heights of the two V-shaped reference blocks 2 are the same; the reference positioning mechanism 3 includes a reference cylinder 31, a chuck 32 connected to the extended end of the reference cylinder 31 and used to clamp the end shaft side surface of the shaft workpiece A, and a first center point 33 provided at the center of the chuck 32; the centering and tightening mechanism 4 is slidably connected to the frame 1 through a stroke adjustment mechanism 41. The centering and tightening mechanism 4 includes a tightening cylinder 42 and a second center point 43 provided at the extended end of the tightening cylinder 42; the first center point 33 and the second center point 43 are driven to tighten the conical grooves A1 at the centers of both ends of the shaft workpiece A.

[0044] As an optional implementation of the present invention, the shaft workpiece A to be machined is placed on the two V-shaped reference blocks 2. Due to the gravity of the shaft workpiece A itself, the center lines of the two conical holes at both ends of the shaft workpiece A placed on the two V-shaped reference blocks 2 (i.e., the axis of the shaft workpiece A) are parallel to the stroke directions of the tightening cylinder 42 and the reference cylinder 31, and the height does not exceed the first center point 33 and the second center point 43; subsequently, the reference cylinder 31 drives the chuck 32 towards the end face of the shaft workpiece A, so that the chuck 32 moves to the reference point; the tightening cylinder 42 drives the second center point 43 to move towards the shaft workpiece A. After the second center point 43 contacts the shaft workpiece A, it continues to push the shaft workpiece A. When both the first center point 33 and the second center point 43 contact the conical hole, due to the guiding cooperation between the conical hole and the inclined surface of the center point, under the pushing action of the tightening cylinder 42, the shaft workpiece A is lifted until the first center point 33 and the second center point 43 clamp the shaft workpiece A, thus completing the center positioning of the shaft workpiece A; subsequently, the chuck 32 starts to operate and clamps the end shaft side surface of the shaft workpiece A to complete the clamping and positioning of the shaft workpiece A.

[0045] Among them, as the name implies, the stroke adjustment mechanism 41 should be understood as a component that can adjust the installation position of the tightening mechanism on the frame 1. Therefore, the distance between the first center 33 and the second center 43 is adjustable, and it can thus be compatible with shaft workpieces A of different length specifications. As for the specific structure of the stroke adjustment mechanism 41, a guide rail method described later can be adopted, or other existing methods can also be used. This technical solution does not make specific limitations on this; The reference cylinder 31 is installed with a chuck 32 through a motor 35 (preferably a servo or stepper motor). (The chuck 32 can adopt an existing three-jaw chuck, and this technical solution does not make limitations on this.) The second center 43 is installed on the extending end of the tightening cylinder 42 through a bearing, so that the motor 35 can drive the shaft workpiece A to rotate to a surface suitable for tool machining according to the program setting during machining. Of course, these are all necessary features of existing shaft positioning mechanisms, and this technical solution does not elaborate on them too much.

[0046] In this technical solution, the first center 33 and the second center 43 lift the shaft workpiece A to complete centering and positioning, and then the chuck 32 clamps the shaft. Compared with the existing positioning method (one end only uses the chuck 32 and the other end uses a center), since both ends are restricted by the centers, the coaxiality is obviously higher. And the chuck 32 only provides clamping on the side surface of the shaft to transmit the radial driving force of the motor 35, without the need for a high clamping force. Therefore, it does not interfere with the positioning reference, can significantly enhance the rigidity during the machining of the shaft workpiece A, reduce bending deformation, and will not damage the machined surface of the shaft surface. It is suitable for precision machining (such as grinding, high-precision turning, heavy turning or long shaft machining), has higher seismic resistance during the machining process, and the positioning process is not complicated either, and can meet the requirements of current rapid automated machining production.

[0047] Through the above structure, the existing positioning method for the shaft workpiece A is optimized, so that the shaft workpiece A has higher coaxiality during the machining process, and there is no need for a high clamping force of the chuck 32, significantly reducing the risk of damage to the workpiece, and can meet the requirements of current high-precision and rapid automated machining production, and can also flexibly respond when facing the machining of shaft workpieces A with different specifications and characteristics.

[0048] Such as Figure 3 And Figures 7-8 As shown, a reference slide rail 34 is also provided on the base frame, and the chuck 32 is slidably connected to the reference slide rail 34.

[0049] As an optional embodiment of the present invention, as described above, the chuck 32 and the first center point 33 at the center of the chuck 32 need to be moved to the reference point (i.e., the zero point or origin in the machining program) first. Therefore, the setting of the reference slide rail 34 provides a stable movement path for the positioning of the chuck 32 and the first center point 33, ensuring that the movement directions of the second center point 43 and the shaft workpiece A are parallel to the axial direction of the shaft workpiece A. The specific number of the reference slide rails 34 can be one or multiple. In this technical solution, two are preferably used.

[0050] As Figure 7 shown, the chuck 32 is a floating jaw power chuck, and a flexible pad is provided on the inner side of the jaws in the chuck 32.

[0051] As an optional embodiment of the present invention, the floating jaws and the flexible pad make it less likely to damage the shaft workpiece A by the clamping force on the axial surface of the shaft workpiece A. The floating jaw power chuck and the flexible pad are both existing technologies, and thus will not be elaborated in this technical solution. Moreover, the specific number of the jaws is not specifically limited in this technical solution.

[0052] As Figures 4-5 shown, the opening height of the two V-shaped reference blocks 2 is such that when the shaft workpiece A is properly placed, the height of the tapered grooves A1 at both ends of the shaft workpiece A does not exceed the heights of the first center point 33 and the second center point 43.

[0053] As an optional embodiment of the present invention, as described above, to enable the first center point 33 and the second center point 43 to have a lifting action on the shaft workpiece A, the opening height of the upper parts of the two V-shaped reference blocks 2 needs to be limited. The advantage of such a design is that the process of the first center point 33 and the second center point 43 can proceed smoothly, and there is no need for the two V-shaped reference blocks 2 to have steps of lowering or raising, reducing the design cost, consumable cost, and energy consumption cost. Among them, the tapered holes at both ends of the shaft workpiece A can be the hole design of the shaft workpiece A itself, or can be carried on the shaft workpiece A by relying on a detachable fixture. This technical solution does not limit this; for the position distribution of the two V-shaped reference blocks 2 in the axial direction of the shaft workpiece A, it is preferably near the end positions of the shaft workpiece A.

[0054] Through the above structure, the existing positioning method for the shaft workpiece A is optimized, enabling the shaft workpiece A to have higher coaxiality during the machining process, and there is no need for the chuck 32 to have a high clamping force, significantly reducing the risk of damage to the workpiece, meeting the requirements of current high-precision and fast automated machining production, and being able to flexibly respond when facing the machining of shaft workpieces A with different specifications and characteristics.

[0055] As Figure 3 And Figures 7-8 shown, a reference slide rail 34 is further provided on the base frame, and the chuck 32 is slidably connected to the reference slide rail 34.

[0056] As an alternative embodiment of the present invention, as described above, the chuck 32 and the first center point 33 at the center of the chuck 32 need to be moved to the reference point (i.e., the zero point or origin in the machining program) first. Therefore, the provision of the reference slide rail 34 provides a stable moving path for the positioning of the chuck 32 and the first center point 33, ensuring that the moving directions of the second center point 43 and the shaft workpiece A are parallel to the axial direction of the shaft workpiece A. The specific form of the reference slide rail 34 can be a single one or multiple ones. In this technical solution, preferably two are used.

[0057] As Figure 7 shown, the chuck 32 is a floating jaw power chuck, and a flexible pad is provided on the inner side of the jaws in the chuck 32.

[0058] As an alternative embodiment of the present invention, the floating jaws and the flexible pad make it less likely for the clamping force on the axial surface of the shaft workpiece A by the jaws to damage the shaft workpiece A. The floating jaw power chuck and the flexible pad are both existing technologies, and thus will not be elaborated in this technical solution. Also, the specific number of the jaws is not specifically limited in this technical solution.

[0059] As Figures 4-5 shown, the opening height of the two V-shaped reference blocks 2 is such that when the shaft workpiece A is properly placed, the height of the tapered grooves A1 at both ends of the shaft workpiece A does not exceed the height of the first center point 33 and the second center point 43.

[0060] As an alternative embodiment of the present invention, as described above, to enable the first center point 33 and the second center point 43 to have a lifting action on the shaft workpiece A, the opening height of the upper part of the two V-shaped reference blocks 2 needs to be limited. The advantage of such a design is that the process of the first center point 33 and the second center point 43 can proceed smoothly, and there is no need for the two V-shaped reference blocks 2 to have steps of lowering or raising, reducing the design cost, consumable cost, and energy consumption cost. Among them, the tapered holes at both ends of the shaft workpiece A can be the hole design of the shaft workpiece A itself or can be carried on the shaft workpiece A by relying on a detachable fixture. This technical solution does not limit this; for the position distribution of the two V-shaped reference blocks 2 in the axial direction of the shaft workpiece A, it is preferably at the end positions close to the shaft workpiece A.

[0061] As Figures 9-11 shown, the tightening cylinder 42 is installed on the base 413 through the vertical frame 44. The centering and tightening mechanism 4 further includes: a tightening slide rail 45, fixedly connected to the base 413; a vertical plate 46, parallel to the vertical frame 44 and slidably connected to the tightening slide rail 45; a mounting seat 47, used for rotatably mounting the second center point 43 and fixedly connected to one side of the vertical plate 46 close to the reference positioning mechanism 3.

[0062] As an alternative embodiment of the present invention, during the movement of the second center 43, the driving force is provided by the clamping cylinder 42, causing the vertical plate 46 to slide on the clamping guide rail 45, thereby driving the movement of the second center 43 on the mounting seat 47. The second center 43 can be installed in the mounting seat 47 through a bearing (or a floating bearing) to ensure that the shaft workpiece A can rotate freely under the drive of the motor 35 during the machining process. Of course, the specific number of the clamping guide rails 45 is not specifically limited in this technical solution.

[0063] As Figure 3 shown in Figure 5 Figure, an infrared opposed sensor 5 for detecting the presence or absence of the shaft workpiece A is further provided on the machine frame 1.

[0064] As an alternative embodiment of the present invention, the infrared opposed sensor 5 is a common method for detecting the presence or absence. In this technical solution, after the shaft workpiece A to be machined is placed on the two V-shaped reference blocks 2, after the infrared opposed sensor 5 detects the presence of the workpiece, it sends an instruction to the machining system. After the system receives the instruction, it issues a positioning instruction, and the reference cylinder 31 starts to drive the chuck 32 to the reference point; if no workpiece is detected, the positioning process is not performed, or an alarm is given when no workpiece is detected for a long time.

[0065] With the above structure, when there is a shaft workpiece A to be machined placed, the positioning mechanism can automatically generate an instruction, and further enables the positioning mechanism to automatically perform the positioning operation, with a high degree of automation, no need for manual operation, and more convenient to use.

[0066] As Figure 2 Figure shows, a chip collecting hopper 7 is further provided on the machine frame 1 and located below the V-shaped reference blocks 2, and a waste collecting box 71 is further provided at the bottom opening of the chip collecting hopper 7.

[0067] As an alternative embodiment of the present invention, since there is only the V-shaped reference block 2 below the shaft workpiece A to be machined, there is less occlusion above, so the chip collecting hopper 7 is designed to facilitate the collection of chips generated during machining, and the waste collecting box 71 facilitates the removal of the collected waste chips.

[0068] With the above structure, it is convenient to collect the waste chips generated during the machining of the shaft workpiece A and to remove them.

[0069] Embodiment 2: Please refer to Figures 1-10 , the present invention also provides the following technical solution: a positioning method for shaft machining, applied to the positioning mechanism in Embodiment 1, including the following steps: Place the shaft workpiece A on the two V-shaped reference blocks 2, and the two V-shaped reference blocks 2 respectively support both ends of the shaft workpiece A; Start the reference cylinder 31, and the first center 33 moves towards the shaft workpiece A to the reference position; Start the clamping cylinder 42, and the second center 43 moves towards the shaft workpiece A, pushing the shaft workpiece A so that both ends of the shaft workpiece A are lifted and clamped by the second center 43 and the first center 33; Start the chuck 32 to clamp the shaft side surface of the shaft workpiece A.

[0070] As an optional embodiment of the present invention, the shaft workpiece A to be machined can be placed on the two V-shaped reference blocks 2 by a gantry crane or a manipulator. When the infrared pair sensor 5 detects the presence of the workpiece, it issues an instruction. After the control system receives the instruction, it controls the reference cylinder 31 to start running, so that the first center 33 reaches the position. Subsequently, the second center 43 completes the centering and clamping positioning of the shaft workpiece A. Finally, the jaws on the chuck 32 clamp the shaft side surface of the shaft workpiece A, and then machining can start. The advantage of such a positioning method is that the machining origin is determined first, and centering positioning and finding the origin can be completed simultaneously, and the damage to the shaft workpiece A during the clamping of the chuck 32 and during the machining process is relatively small.

[0071] Through the above method, centering positioning and finding the origin can be completed simultaneously, and the damage to the shaft workpiece A is relatively small, which can meet the requirements of current high-precision and fast automated machining production.

[0072] Embodiment 3: Please refer to Figures 3-5 And Figures 12-13 , the present invention also provides the following technical solution: a positioning mechanism for crankshaft machining, including the positioning mechanism in Embodiment 1, and further including an angular positioning mechanism 6, which is arranged on the frame 1 and located between the two V-shaped reference blocks 2. The angular positioning mechanism 6 includes: A lifting mechanism 61, fixedly connected to the frame 1; A clamping mechanism 62, arranged at the output end of the lifting mechanism 61. When the clamping mechanism 62 operates, it can clamp the crankshaft a.

[0073] As an optional embodiment of the present invention, compared with Embodiment 1, when the angular positioning mechanism 6 operates, after completing the centering process, first the lifting mechanism 61 drives the clamping mechanism 62 upward, and then the clamping mechanism 62 clamps the crankshaft a, clamping the shaft side surface of the crankshaft a, so that the radial angle of a single segment of the crankshaft a is determined. In the machining program, the current angle can be used as the machining zero point, or the current angle can be adjusted to the zero point in the machining program. Those skilled in the art can make any setting for this, so it can be used for the radial positioning of the crankshaft a.

[0074] Through the above structure, the radial positioning of the crankshaft a is achieved with a relatively simple structure, and it can also be compatible with crankshafts a of different length specifications, with high positioning accuracy, and the surface of the crankshaft a is not easily damaged by the chuck 32 during the machining process.

[0075] As Figures 12-13 shown, the lifting mechanism 61 includes a lifting cylinder 611, and the clamping mechanism 62 includes a clamping cylinder 621 and two clamping jaws 622 provided on the clamping cylinder 621. When the clamping cylinder 621 operates, the two clamping jaws 622 separate or approach each other.

[0076] As an optional implementation scheme of the present invention, this embodiment only provides lifting and clamping. Therefore, the radial angles after the segments corresponding to the lifting mechanism 61 placed here are clamped are unified. Therefore, the determination of this zero point is the same. And during the radial positioning process, the forces applied to both sides of the segment of the crankshaft a are less likely to cause the crankshaft a to rotate due to unbalanced force compared to the case of single-sided force application, making the positioning result more accurate.

[0077] Embodiment 4: Please refer to Figure 13 , the present invention also provides the following technical solutions: including the positioning mechanism for crankshaft machining in Embodiment 3, and further including a first auxiliary guide rail 63 provided on the frame 1. The lifting cylinder 611 is slidably connected to the first auxiliary guide rail 63, and the lifting cylinder 611 slides in the horizontal plane and the sliding direction is perpendicular to the length direction of the reference slide rail 34.

[0078] As an optional implementation scheme of the present invention, the angular positioning mechanism 6 in Embodiment 3 can only be used for radial positioning. However, as is well known, during the machining of shaft parts, there may be tangential forces on the shaft workpiece A, such as milling, turning, drilling, etc. These forces are likely to cause the rotation of the shaft workpiece A. Since the method of centering first and then clamping is adopted in Embodiment 1, and the chuck 32 adopts the floating jaw power chuck 32 and the flexible pad, this results in the situation that the shaft workpiece A is likely to rotate when subjected to tangential forces during the machining process, or it is likely to exist that the chuck 32 scratches the shaft side surface of the shaft workpiece A. This phenomenon is more obvious during the machining of a single segment of the crankshaft a applied in this embodiment. Then, during the machining process, the angular positioning mechanism 6 can be relied on to provide auxiliary clamping force. The specific method is: after the radial positioning of the zero point is completed, the angular positioning mechanism 6 releases the segment, the motor 35 drives the chuck 32 to rotate, so that the crankshaft a rotates to a suitable machining angle. Then, the lifting cylinder 611 in the angular positioning mechanism 6 moves on the first auxiliary guide rail 63, then moves upward, and finally the clamping mechanism 62 re-clamps the surface of a single segment of the crankshaft a and maintains it during the machining process of the crankshaft a until the crankshaft a needs to be re-adjusted for the radial angle and then the steps of releasing - clamping are repeated.

[0079] Therefore, the angular positioning mechanism 6 can not only achieve the radial positioning of the crankshaft a, facilitating the quick finding of the zero point in the machining program, but also maintain the clamping of the crankshaft a during machining processes such as boring, milling, turning, planing, and drilling, thereby maintaining the radial angle of the crankshaft a. Thus, there is no need for the chuck 32 to provide excessive clamping force to damage the surface of the crankshaft a, nor is there a need to worry about insufficient clamping force of the chuck 32 causing the crankshaft a to rotate during machining and affecting the machining accuracy.

[0080] With the above structure, on the basis of facilitating the quick finding of the radial zero point during the machining of the crankshaft a, it is possible to further provide an auxiliary holding force for the radial angle of the crankshaft a during the machining process. There is no need to rely on the chuck 32 to provide excessive clamping force to damage the surface of the crankshaft a, nor is there a need to worry about insufficient clamping force of the chuck 32 causing the crankshaft a to rotate during machining and affecting the machining accuracy.

[0081] As Figure 13 shown, it further includes a second auxiliary guide rail 64 provided on the frame 1. The first auxiliary guide rail 63 is slidably connected to the second auxiliary guide rail 64. The first auxiliary guide rail 63 slides in the horizontal plane and the sliding direction is parallel to the length direction of the reference slide rail 34.

[0082] As an optional implementation of the present invention, similarly, for the crankshaft a, different segments may need to be machined. Therefore, the segment clamped by the angular positioning mechanism 6 also needs to be machined. Thus, when machining this segment of the crankshaft a, the angular positioning mechanism 6 needs to move horizontally to clamp the non-machined segment. Therefore, the first auxiliary guide rail 63, the second auxiliary guide rail 64, and the lifting cylinder 611 of the angular positioning mechanism 6 in this embodiment can be regarded as an X-Y-Z module. In fact, since the segments of the crankshaft a are basically in standard specifications and not very long, a shorter stroke can be set in each direction.

[0083] With the above structure, the angular positioning mechanism 6 can replace the clamped segment, ensuring that each segment of the crankshaft a can be machined and that each segment of the crankshaft a has an auxiliary clamping force during the machining process to ensure the machining accuracy.

[0084] As Figure 13 shown, it further includes a driving mechanism 65. The two driving mechanisms 65 are respectively used to drive the lifting cylinder 611 to slide on the first auxiliary guide rail 63 and drive the first auxiliary guide rail 63 to slide on the second auxiliary guide rail 64. The driving mechanism 65 includes one of a screw-nut translation mechanism, a cylinder, a hydraulic cylinder, etc.

[0085] As an optional embodiment of the present invention, the driving mechanism 65 can drive the lifting cylinder 611 to slide on the first auxiliary guide rail 63 and drive the first auxiliary guide rail 63 to slide on the second auxiliary guide rail 64, so that the operation of the entire angular positioning mechanism 6 to provide clamping force during the processing can be fully automated. The specific manner of the driving mechanism 65 is not limited in this technical solution, and those skilled in the art can specifically select according to the actual specifications of the crankshaft a. In this technical solution, a screw and nut translation mechanism is preferably used, which can provide a relatively reliable holding force for maintaining the radial angle during the processing of the crankshaft a.

[0086] Through the above structure, the operation of the entire angular positioning mechanism 6 to provide clamping force during the processing can be fully automated.

[0087] Embodiment 5: Please refer to Figures 1-3 With Figure 12 , the present invention also provides the following technical solution: a positioning method for crankshaft machining, applied to the positioning mechanism for crankshaft machining in Embodiment 3, including the positioning method for shaft machining in Embodiment 2. Before step S5, it further includes: S4. Start the lifting cylinder 611 to drive the clamping mechanism 62 to rise. After rising to the position, start the clamping cylinder 621 to clamp the segment of the crankshaft a to achieve angular positioning of the crankshaft a.

[0088] As an optional embodiment of the present invention, before performing the radial positioning of the crankshaft a, due to the need to conform to the aforementioned positioning idea of centering first and then clamping, the operation of the angular positioning mechanism 6 should be after centering and before clamping to ensure the accuracy of the crankshaft a during the processing.

[0089] The working principle and usage process of the present invention: The workpiece A of the shaft to be processed is placed on two V-shaped reference blocks 2. Due to the self-weight of the shaft workpiece A, the center lines of the two tapered holes at both ends of the shaft workpiece A placed on the two V-shaped reference blocks 2 (i.e., the axis of the shaft workpiece A) are parallel to the stroke directions of the jacking cylinder 42 and the reference cylinder 31, and the height does not exceed the first center point 33 and the second center point 43; subsequently, the reference cylinder 31 drives the chuck 32 towards the end face of the shaft workpiece A, so that the chuck 32 moves to the reference point; the jacking cylinder 42 drives the second center point 43 to move towards the shaft workpiece A. After the second center point 43 contacts the shaft workpiece A, it continues to push the shaft workpiece A. When both the first center point 33 and the second center point 43 contact the tapered hole, due to the guiding fit of the tapered hole and the inclined surface of the center point, under the pushing action of the jacking cylinder 42, the shaft workpiece A is lifted until the first center point 33 and the second center point 43 clamp the shaft workpiece A, thereby completing the center positioning of the shaft workpiece A; subsequently, the chuck 32 starts to operate and clamps the shaft side surface at the end of the shaft workpiece A to complete the clamping and positioning of the shaft workpiece A.

[0090] As described above, it is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered within the protection scope of the present invention.

Claims

1. A positioning mechanism for shaft machining, comprising a frame, V-shaped reference blocks provided on the frame for supporting both ends of a shaft workpiece, and a reference positioning mechanism and a centering and clamping mechanism located at both ends of the frame. The heights of the two V-shaped reference blocks are the same. It is characterized in that: The reference positioning mechanism includes a reference cylinder, a chuck connected to the extending end of the reference cylinder and used for clamping the shaft side surface of the end of the shaft workpiece, and a first center point provided at the center of the chuck; The centering and clamping mechanism is slidably connected to the frame through a stroke adjustment mechanism. The centering and clamping mechanism includes a clamping cylinder and a second center point provided at the extending end of the clamping cylinder; The first center point and the second center point are driven to clamp the tapered grooves at the centers of both ends of the shaft workpiece.

2. The positioning mechanism for shaft machining according to claim 1, characterized in that, A reference slide rail is further provided on the base frame, and the chuck is slidably connected to the reference slide rail.

3. The positioning mechanism for shaft machining according to claim 1, characterized in that, The chuck is a floating jaw power chuck, and a flexible pad is provided on the inner side of the jaws in the chuck.

4. The positioning mechanism for shaft machining according to claim 1, characterized in that, The opening height of the two V-shaped reference blocks is such that when the shaft workpiece is placed, the height of the tapered grooves at both ends of the shaft workpiece does not exceed the heights of the first center point and the second center point.

5. The positioning mechanism for shaft machining according to claim 1, characterized in that, The stroke adjustment mechanism includes: A stroke guide rail fixedly connected to the frame; A rack fixedly connected to the frame; A base slidably connected to the stroke guide rail, and the clamping cylinder is installed on the base; A speed reducer fixedly installed on the base. A gear cooperating with the rack is provided at the output end of the speed reducer, and a handwheel is connected to the input end of the speed reducer; A locking member for locking the position of the base on the stroke guide rail.

6. The positioning mechanism for shaft machining according to claim 5, characterized in that, The clamping cylinder is installed on the base through an upright frame. The centering and clamping mechanism further includes: A clamping guide rail fixedly connected to the base; A vertical plate parallel to the upright frame and slidably connected to the clamping guide rail; A mounting seat for rotatably mounting the second center point and fixedly connected to one side of the vertical plate close to the reference positioning mechanism.

7. The positioning mechanism for shaft machining according to claim 1, characterized in that, An infrared opposed sensor for detecting the presence or absence of the shaft workpiece is further provided on the frame.

8. A positioning method for shaft machining, applied to the positioning mechanism described in any one of claims 1-7, characterized in that, Including the following steps: Place the shaft workpiece on the two V-shaped reference blocks, and the two V-shaped reference blocks respectively support both ends of the shaft workpiece; Start the reference cylinder, and the first center point moves towards the shaft workpiece to the reference position; Start the clamping cylinder, and the second center point moves towards the shaft workpiece, pushing the shaft workpiece so that both ends of the shaft workpiece are lifted and clamped by the second center point and the first center point; Start the chuck to clamp the shaft side surface of the shaft workpiece.

9. A positioning mechanism for crankshaft machining, comprising the positioning mechanism according to any one of claims 1-7, characterized in that, It further includes an angular positioning mechanism provided on the frame and located between the two V-shaped reference blocks. The angular positioning mechanism includes: A jacking mechanism fixedly connected to the frame; A clamping mechanism provided at the output end of the jacking mechanism. The clamping mechanism can clamp the crankshaft when it operates.

10. The positioning mechanism for crankshaft machining according to claim 9, characterized in that, The jacking mechanism includes a jacking cylinder, and the clamping mechanism includes a clamping cylinder and two jaws provided on the clamping cylinder. When the clamping cylinder operates, the two jaws move away from or close to each other.

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