Self-centering clamping device of inverted lathe

Abstract

The utility model relates to the technical field of tool clamp structures, in particular to a self-centering clamping device of an inverted lathe. Comprising a positioning assembly and a clamping assembly, and the positioning assembly comprises a mandrel and a positioning block; the positioning block is of an annular structure which annularly sleeves the outer side of the core shaft; the lower end of the mandrel extends out of a shaft body of the positioning block and is provided with a big-end-up first conical surface; the clamping assembly comprises a flange pull rod and an expansion sleeve; the flange pull rod is of a rod-shaped structure with the upper end connected with vertical driving equipment, and the flange pull rod and the mandrel are coaxially arranged. The expansion sleeve is of an annular structure which is arranged between the positioning block and the mandrel in a sleeved mode and is coaxial with the mandrel, a second conical face tightly attached to the first conical face is arranged on the inner side of the lower end of the expansion sleeve, and the upper end of the expansion sleeve is fixedly connected with the flange pull rod. The outer side of the lower end of the expansion sleeve expands outwards to clamp a workpiece when the expansion sleeve moves upwards, and contracts inwards to loosen clamping of the workpiece when the expansion sleeve moves downwards. The clamping device is simple in structure and extremely high in positioning precision.

Description

Technical Field

[0001] The utility model relates to the technical field of tooling fixture structures, in particular to a self-centering clamping device for an inverted lathe. Background Art

[0002] The crankshaft hub is an important component of the automobile engine assembly and is a safety precision part. The function of the crankshaft hub is to transmit the torque of the crankshaft to the crankshaft damping pulley, timing sprocket, and oil pump sprocket. The crankshaft hub is fixed to the crankshaft by M14 bolts, and the friction is formed by pressing the timing sprocket, oil pump sprocket and crankshaft to drive the timing sprocket and oil pump sprocket, and the crankshaft damping pulley is fixed by three bolt holes on the big head end face, so as to transmit the crankshaft torque to the damping pulley to drive the accessory system to work. Since the crankshaft hub needs to cooperate with the timing gear and oil pump sprocket, in order to ensure the assembly clearance and matching accuracy between the products and reduce the noise of the engine and increase the service life of the engine, it is necessary to ensure that the various dimensional shape and position tolerances of the hub are qualified, and the processing capacity during mass production is within a stable range. In particular, the surface roughness, finish and surface processing texture of the large outer circle are crucial to the life of the engine, and are also the most effective way to curb the noise or functional failure of the engine at an early stage.

[0003] There are many kinds of processing devices for crankshaft hubs. For example, the Chinese invention patent with patent number "CN109454295B" and titled "A gear grinding fixture for processing shaft parts with holes and its use method" proposes a fixture, which includes a hydrostatic mandrel, a positioning seat, a guide head and an expansion sleeve; a first hole is opened in the hydrostatic mandrel, a second hole is opened in the positioning seat, and a third hole is opened in the guide head; the first hole, the second hole, the inner hole of the expansion sleeve and the third hole are connected to form a guide hole for installing a guide mechanism; when in use, the input shaft of the shaft part with a hole is located on the upper part of the guide head, and the guide head extends into the inner hole of the input shaft. The guide mechanism includes a guide rod, a spring and a guide seat. When the top of the guide rod is pressed by the input shaft, the spring contracts, the expansion sleeve expands, and the input shaft is tightly clamped on the gear grinding fixture. After the processing is completed, the expansion sleeve contracts, the expansion sleeve and the input shaft are loosened, and then the spring stretches, the guide rod pops out, and the input shaft is ejected, which is convenient for the robot to load and unload the input shaft. The guide mechanism can realize automatic loading and unloading, with high efficiency, while ensuring the precision requirements of the gear ring. However, there are also some problems with this fixture, that is, the shaft body parts to be processed need to have an inner hole cone surface, and the positioning of the shaft body parts and the positioning seat is achieved by the inner hole cone surface and the positioning seat cone surface completely fitting to achieve the positioning effect. This is obviously not feasible for some shafts that do not have an inner hole cone surface, and the fixture does not have the kinetic energy of self-centering clamping.

[0004] The existing fixture structures generally have the problem of poor positioning accuracy, low automation and production efficiency, and it is difficult to ensure the accuracy of key dimensions, which increases the generation of waste and causes great waste, while also extending the working time and labor intensity of processing workers. Utility Model Content

[0005] The purpose of the utility model is to solve the deficiencies of the above-mentioned background technology and provide a self-centering clamping device for an inverted lathe.

[0006] The technical solution of the utility model is: a self-centering clamping device for an inverted lathe, comprising:

[0007] A positioning assembly, the positioning assembly comprising a core shaft and a positioning block; the positioning block is an annular structure sleeved on the outside of the core shaft and coaxially fixed with the core shaft; the lower end of the core shaft extends out of the shaft body of the positioning block and is provided with a first conical surface with a smaller bottom and a larger top;

[0008] The clamping assembly includes a flange pull rod and an expansion sleeve; the flange pull rod is a rod-shaped structure whose upper end is connected to a vertical driving device, and the flange pull rod is coaxially arranged with the core shaft; the expansion sleeve is an annular structure which is sleeved between the positioning block and the core shaft and coaxially arranged with the core shaft, and a second conical surface which fits tightly with the first conical surface is provided on the inner side of the lower end of the expansion sleeve, and the upper end of the expansion sleeve is fixedly connected to the flange pull rod, and the outer side of the lower end of the expansion sleeve expands outward to clamp the workpiece when the expansion sleeve moves upward, and contracts inward to release the clamping of the workpiece when the expansion sleeve moves downward.

[0009] According to a self-centering clamping device for an inverted lathe provided in the present application, a plurality of partition grooves are opened at the lower end of the expansion sleeve; the lower ends of the partition grooves are flush with the lower end of the expansion sleeve, the partition grooves pass through the outer side surface and the inner side surface of the expansion sleeve, and the plurality of partition grooves are evenly spaced in the circumferential direction with the axis of the expansion sleeve as the center, dividing the lower part of the expansion sleeve into a plurality of expansion blocks.

[0010] According to the self-centering clamping device for an inverted lathe provided in the present application, the partition groove is filled with a filler.

[0011] According to a self-centering clamping device for an inverted lathe provided in the present application, a circle base is arranged on the upper end of the expansion sleeve; a flange seat is arranged on the upper end of the core shaft; a flange plate is arranged on the flange pull rod; connecting bolts are arranged on the base; the connecting bolts pass through the base, the flange seat and the flange plate in sequence, and a positioning spacer is arranged on the connecting bolt; the positioning spacer is fixedly connected to the connecting bolt, and the upper and lower ends of the positioning spacer are respectively pressed against the flange plate and the base.

[0012] According to a self-centering clamping device for an inverted lathe provided in the present application, there are a plurality of positioning spacers, and the plurality of positioning spacers are arranged at equal intervals in a circumferential direction with the axis of the expansion sleeve as the center.

[0013] According to a self-centering clamping device for an inverted lathe provided in the present application, a plurality of groups of positioning air holes are provided on the lower end surface of the positioning block, and the plurality of groups of positioning air holes are arranged at equal intervals in the circumferential direction with the axis of the positioning block as the center.

[0014] According to the self-centering clamping device of an inverted lathe provided in the present application, it also includes a loading and unloading tray; the loading and unloading tray is provided with a positioning ring for fixing the workpiece during loading and a positioning pin for fixing the workpiece during unloading.

[0015] According to the self-centering clamping device of an inverted lathe provided in the present application, it also includes a transition plate, which is an annular structure fixedly connected to the positioning block, and the inner cylindrical surface of the transition plate is tightly fitted to the circumferential outer side of the flange plate of the flange pull rod.

[0016] According to a self-centering clamping device for an inverted lathe provided in the present application, a guide hole is provided at the axial center position of the upper end of the flange seat; the lower end of the flange pull rod is axially movably connected to the guide hole.

[0017] According to a self-centering clamping device for an inverted lathe provided in the present application, an O-ring is provided on the inner side of the guide hole.

[0018] The advantages of the present application are as follows: 1. The present application is an inverted drive clamping structure, which adopts the method of driving the expansion sleeve to move while the mandrel does not move to clamp and loosen, and can well clamp and fix the crankshaft hub workpiece in conjunction with the inverted lathe, the positioning accuracy is greatly improved, the efficiency of the clamping process is also greatly improved, the entire clamping device has a simple structure, and is easy to operate and use;

[0019] 2. The present application provides a partition groove on the expansion sleeve, which divides the lower part of the expansion sleeve into a plurality of expansion blocks, so that the expansion blocks can expand outwards and contract inwards more easily during the movement of the expansion sleeve, and the clamping of the workpiece is faster and more secure. The evenly distributed expansion block structure can automatically perform centering operation on the workpiece, which is extremely convenient to use;

[0020] 3. The present application sets a filler in the partition groove, and the filler occupies the space of the partition groove in advance, so as to prevent impurities from entering the partition groove and causing obstruction to the partition groove during the workpiece processing. The filled filler increases the service life of the expansion sleeve and reduces the processing cost;

[0021] 4. The present application sets a positioning sleeve between the flange and the base. The positioning sleeve can ensure a safe distance between the flange tie rod and the expansion sleeve, avoid the problem of deviation in the degree of tightening of the connecting bolts during installation, and avoid the problem that the expansion sleeve cannot clamp the workpiece well due to being too large or too small, which greatly facilitates the installation between the flange tie rod and the expansion sleeve;

[0022] 5. In this application, multiple positioning spacers are evenly arranged on the flange tie rod and the expansion sleeve, so that each position between the flange tie rod and the expansion sleeve is at a suitable spacing, ensuring that the flange tie rod and the expansion sleeve are coaxially arranged, and the installation accuracy is improved;

[0023] 6. The present application sets a positioning air hole on the lower end surface of the positioning block. The positioning air hole can judge whether it is closely fitted with the upper end surface of the workpiece below by monitoring the air pressure, and judge whether the workpiece is installed in place, which has a good error-proofing recognition function;

[0024] 7. The present application can facilitate loading and unloading of workpieces by setting loading and unloading trays. When loading, the workpiece is placed in the positioning ring, which is convenient for the clamping device to grab it. When unloading, the workpiece is directly placed on the positioning pin to avoid mistakes, facilitate subsequent transportation, and greatly improve the processing efficiency;

[0025] 8. The present application is provided with a transition plate, which is a fixed component of the entire clamping device connected to the lathe. The transition plate can guide and limit the flange pull rod to avoid non-axial movement of the flange pull rod when driving the expansion sleeve, thereby improving the clamping accuracy;

[0026] 9. The present application sets a guide hole on the flange seat, which is used in conjunction with the flange tie rod and also guides the flange tie rod axially to avoid non-axial displacement and further improve the processing accuracy;

[0027] 10. The present application improves the sealing performance of the guide hole and the flange pull rod by setting an O-ring between the guide hole and the flange pull rod, thereby preventing debris from entering the guide hole and making the axial movement of the flange pull rod smoother.

[0028] The clamping device of the present application has a simple structure and can accurately clamp the workpiece when applied to an inverted lathe. It has extremely high positioning accuracy and stable clamping and grasping, which improves the processing efficiency of the workpiece and has great promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 : A schematic diagram of the structure of the clamping device of the present application;

[0030] Figure 2 : Bottom view of the clamping device of the present application;

[0031] Figure 3 : A schematic diagram of the clamping device of the present application clamping a workpiece from a loading and unloading tray;

[0032] Figure 4 : A schematic diagram of the clamping device of the present application placing a workpiece on a loading and unloading tray;

[0033] Among them: 1-core shaft; 2-positioning block; 3-flange pull rod; 4-expansion sleeve; 5-slot; 6-base; 7-flange seat; 8-flange plate; 9-positioning spacer; 10-positioning air hole; 11-loading and unloading tray; 12-positioning ring; 13-positioning pin; 14-transition plate; 15-O-ring. DETAILED DESCRIPTION

[0034] The embodiments of the present invention are described in detail below, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0035] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and 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, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0036] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0037] The utility model is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0038] The present application relates to a self-centering clamping device for an inverted lathe. The clamping device of the present application is used for an inverted lathe. The inverted lathe is the power source of the clamping device of the present application. The clamping device is fixed on the inverted lathe. Unlike the existing clamping method of driving the core shaft to move, the present application drives the expansion sleeve to move vertically by the inverted lathe to achieve clamping and fixing of the workpiece. The crankshaft hub workpiece can be clamped and fixed well, the positioning accuracy is greatly improved, and the efficiency of the clamping processing is also greatly improved.

[0039] Specifically, Figures 1 to 4As shown, the self-centering clamping device of the inverted lathe of the present application includes a positioning assembly and a clamping assembly. The positioning assembly is a fixed component fixed on the inverted lathe, and the clamping assembly is a movable assembly installed on the power output device on the inverted lathe. The positioning assembly includes a core shaft 1 and a positioning block 2. The positioning block 2 is an annular structure which is annularly sleeved on the outside of the core shaft 1 and fixed coaxially with the core shaft 1. The lower end of the core shaft 1 extends out of the shaft body of the positioning block 2 and is provided with a first conical surface which is smaller at the bottom and larger at the top; the clamping assembly includes a flange pull rod 3 and an expansion sleeve 4. The flange pull rod 3 is a rod-shaped structure with the upper end connected to a vertical driving device. The flange pull rod 3 is coaxially arranged with the core shaft 1. The expansion sleeve 4 is an annular structure which is sleeved between the positioning block 2 and the core shaft 1 and is coaxially arranged with the core shaft 1. A second conical surface which is tightly fitted with the first conical surface is provided on the inner side of the lower end of the expansion sleeve 4. The upper end of the expansion sleeve 4 is fixedly connected to the flange pull rod 3. When the expansion sleeve 4 moves upward, the outer side of the lower end of the expansion sleeve 4 expands outward to clamp the workpiece, and when the expansion sleeve 4 moves downward, it contracts inward to release the clamping of the workpiece.

[0040] During actual operation, the workpiece is placed under the entire clamping device, and then the expansion sleeve of the clamping device is inserted into the positioning hole at the upper end of the workpiece by moving the spindle box of the inverted lathe downward as a whole. The inverted lathe drives the expansion sleeve 4 to move vertically upward relative to the core shaft 1. With the cooperation of the first conical surface and the second conical surface, the lower end part of the expansion sleeve 4 rises along the first conical surface. Under the extrusion of the first conical surface, the lower end of the expansion sleeve 4 expands radially outward until it is tightly fitted to the circumferential inner end surface of the positioning hole, thereby fixing the workpiece and completing the clamping of the workpiece. After the workpiece processing is completed, the inverted lathe lowers the workpiece, and drives the expansion sleeve 4 to move vertically downward relative to the core shaft 1. The lower end part of the expansion sleeve 4 descends along the first conical surface, and the lower end of the expansion sleeve 4 contracts radially inward, so that the circumferential outer end surface of the lower end of the expansion sleeve 4 is separated from the circumferential inner end surface of the positioning hole, thereby completing the loosening of the workpiece.

[0041] In some embodiments of the present application, the present embodiment optimizes the structure of the expansion sleeve 4, specifically, Figures 1-2 As shown, a plurality of partition grooves 5 are provided at the lower end of the expansion sleeve 4 of this embodiment, the lower ends of the partition grooves 5 are flush with the lower end of the expansion sleeve 4, the partition grooves 5 pass through the outer side surface and the inner side surface of the expansion sleeve 4, and the plurality of partition grooves 5 are evenly spaced along the circumferential direction with the axis of the expansion sleeve 4 as the center, dividing the lower part of the expansion sleeve 4 into a plurality of expansion blocks.

[0042] That is, the lower end of the expansion sleeve 4 of this embodiment is a split structure, and the lower part of the expansion sleeve 4 is divided into a plurality of expansion blocks by the partition groove 5, such as Figure 2 As shown, in this embodiment, the lower part of the expansion sleeve 4 is evenly divided into six expansion blocks by six partition grooves 5. The expansion blocks are easier to expand and contract radially, react more quickly to the vertical movement of the expansion sleeve 4, require less axial movement force, and clamp the workpiece more efficiently.

[0043] The arrangement of the partition groove 5 results in a large number of gaps between the expansion sleeve 4, the core shaft 1 and the positioning block 2. In order to prevent impurities from entering these gaps, the present embodiment fills the partition groove 5 with fillers in advance. The fillers in the present embodiment are soft materials with a certain viscosity such as silica gel. When the expansion block expands radially, the fillers in the partition groove 5 are squeezed and flow in the gaps between the partition groove 5, the core shaft 1 and the expansion block, and between the expansion block and the positioning block. In this way, these gaps that are easy for impurities to enter can be occupied in advance, thereby avoiding damage to the clamping device due to impurities entering these gaps during the subsequent workpiece processing. Such a design scheme can greatly extend the service life of the entire clamping device.

[0044] In other embodiments of the present application, the present embodiment further optimizes the structure of the expansion sleeve 4, specifically, Figure 1 As shown, a circle base 6 is provided at the upper end of the expansion sleeve 4, and a flange seat 7 is provided at the upper end of the core shaft 1. The base 6 is fixedly connected to the flange plate 8 of the flange pull rod 3 by connecting bolts passing through the base 6 and the flange seat 7. A positioning spacer 9 is sleeved on the connecting bolts, and the positioning spacer 9 is fixedly connected to the connecting bolts. The upper and lower ends of the positioning spacer 9 are respectively pressed against the flange plate 8 and the base 6.

[0045] In this embodiment, there are multiple positioning spacers 9, which are arranged equidistantly along the circumferential direction with the axis of the expansion sleeve 4 as the center. Figure 1 As shown, there are three positioning spacers 9 in this embodiment.

[0046] The axial length of the positioning spacer 9 is set, and the axial ends of the positioning spacer 9 are respectively pressed against the flange 8 and the base 6, so as to limit the axial spacing between the flange pull rod 3 and the expansion sleeve 4. In fact, in order to ensure the axial spacing between the flange 8 and the flange seat 7 of the flange pull rod 3 and the axial spacing between the flange seat 7 and the base 6 of the expansion sleeve 4, it can be ensured that during the movement of the expansion sleeve 4 driven by the flange pull rod 3, there is enough distance so that the expansion block of the expansion sleeve 4 can expand or contract to clamp the workpiece or loosen the workpiece, avoiding the problem of the flange pull rod 3 driving the expansion sleeve 4 to move too small in the axial direction due to the connecting bolts being too tight during the assembly process, resulting in the problem of being unable to clamp or loosen.

[0047] In a further embodiment of the present application, the structure of the positioning block 2 is optimized. Figure 1 , 3 As shown in FIG. 4 , the lower end surface of the positioning block 2 of this embodiment is provided with a plurality of groups of positioning air holes 10 , and the plurality of groups of positioning air holes 10 are arranged at equal intervals along the circumferential direction with the axis of the positioning block 2 as the center.

[0048] The positioning air hole 10 is used to detect whether the workpiece and the clamping device are accurately aligned. When the upper end of the workpiece is in close contact with the lower end of the positioning block 2, the positioning air hole 10 is blocked by the upper end of the workpiece. At this time, the air pressure of the positioning air hole 10 will rise. By monitoring the air pressure of the positioning air hole 10, it can be determined that the workpiece corresponding to the current positioning hole 10 has been aligned. If the air pressure detection of all the positioning air holes 10 meets the requirements, it proves that the alignment of the workpiece and the positioning block 2 is accurate at this time. As long as the air pressure detection of one positioning air hole 10 does not meet the requirements, it can be determined that the workpiece is not aligned and needs to be adjusted.

[0049] In some embodiments of this embodiment, the structure of the flange tie rod 3 is optimized. Specifically, Figure 1 As shown, it also includes a transition plate 14, which is an annular structure fixedly connected to the positioning block 2, and the inner cylindrical surface of the transition plate 14 is tightly fitted on the outer circumference of the flange plate 8 of the flange tie rod 3.

[0050] The transition plate 14 restricts the non-axial movement of the flange plate 8 of the flange tie rod 3, ensuring that the flange tie rod 3 can only move in the axial direction.

[0051] At the same time, in this embodiment, a guide hole is opened at the axial center position of the upper end of the flange seat 7, and the lower end of the flange pull rod 3 is axially movable and connected to the guide hole. The guide hole also limits the flange pull rod 3 in a non-axial direction to ensure that the flange pull rod 3 can only move in the axial direction.

[0052] The transition plate 14 and the guide hole both play the role of axially guiding the flange pull rod 3. In addition, the inner side of the guide hole of the present embodiment is provided with an O-type sealing ring 15 to prevent foreign matter from entering the guide hole.

[0053] In a preferred embodiment of the present application, the clamping device of this embodiment further includes a loading and unloading tray 11, on which a positioning ring 12 for fixing the workpiece during loading and a positioning pin 13 for fixing the workpiece during unloading are provided.

[0054] The positioning ring 12 is actually a groove arranged on the loading and unloading tray 11. The lower end of the workpiece is clamped in the positioning ring 12. The positioning pin 13 is a structure protruding from the loading and unloading tray 11, which is used to place the processed workpiece. In this way, a placement station for the workpiece in different states is constructed, which is convenient for taking and placing and will not cause misoperation.

[0055] The loading and unloading tray 11 of the present embodiment has a total of 20 workstations, which are evenly distributed on an annular loading and unloading workbench. A positioning ring 12 and a positioning pin 13 are inlaid in the loading and unloading tray 11. When loading, the crankshaft hub workpiece is placed in the positioning ring 12. When unloading after the machining step is completed, the crankshaft hub workpiece is placed in the positioning pin 13, thereby realizing automatic loading and unloading of workpieces, precise positioning and error prevention of process parts.

[0056] When the clamping device of the present application is actually operated, the transition plate 14 of the clamping device is fixed to the spindle of the inverted lathe by bolts, the core shaft 1 and the positioning block 2 are fixed to the transition plate 14 by bolts, the flange pull rod 3 is assembled into the transition plate 14, and the other end of the flange pull rod 3 extends into the guide hole at the axial position of the upper end of the flange seat 7. A positioning spacer 9 is inserted into the flange seat 7, and the flange pull rod 3 and the expansion sleeve 4 are fixedly connected as a whole by connecting bolts. The expansion sleeve 4 is between the positioning block 2 and the core shaft 1, and the spacer groove 5 between the expansion blocks of the expansion sleeve 4 is filled with fillers. After the assembly of the clamping device is completed, the workpiece can be clamped;

[0057] A loading and unloading tray 11 is placed under the clamping device, and the crankshaft hub workpiece to be processed is placed in the positioning ring 12. The equipment program is started, and the spindle of the inverted lathe enters the loading bin. Under the preset loading program, the spindle replaces the material grabbing manipulator to find the coordinates directly above the workpiece and descends to make the positioning surface of the positioning block 2 fit with the end face of the workpiece and continue to descend. The air pressure of the positioning air hole 10 on the lower end face of the positioning block 2 is detected. When the upper end face of the workpiece and the positioning air hole 10 are completely sealed to form the system default pressure difference, it proves that the workpiece is accurately positioned at this time and can enter the next processing program. Otherwise, the system alarms to achieve error-proof detection of precise positioning of the workpiece;

[0058] After accurate positioning, the main oil cylinder of the lathe system provides a pressure of 3MPa to drive the flange pull rod 3 to move vertically upward. Under the action of the flange pull rod 3, the expansion sleeve 4 moves vertically upward, and the second cone surface on the inner side of the lower end of the expansion sleeve 4 moves upward on the first cone surface at the lower end of the core shaft 1. Under the extrusion of the first cone surface, the expansion block at the lower end of the expansion sleeve 4 expands radially outward, and the circumferential outer side surface of the expansion block extending into the workpiece positioning hole contacts and presses against the circumferential inner side surface of the positioning hole, completely clamping the workpiece. The workpiece is clamped and self-locked under the reverse expansion action of the expansion sleeve 4, and it can ensure that the workpiece is stably tightened and does not fall off;

[0059] Under the control of the preset program, the spindle of the inverted lathe drives the clamping device from outside the loading area into the processing chamber, and performs fine processing on the outer surface of the crankshaft hub workpiece according to the linear speed and feed speed set by the program. After turning is completed, the tool is automatically retracted according to the set program, and the spindle drives the clamping device and the workpiece to exit the processing chamber and enter the unloading chamber, and the crankshaft hub workpiece is placed on the locating pin 13 in the designated unloading area. The locating ring 12 in the area to be processed and the crankshaft hub workpiece on the locating pin 13 in the processed area form a sharp contrast, which plays a role in preventing errors in the process station, and a fine processing turning condition is completed.

[0060] The clamping device of the present application can be applied to the surface finishing of crankshaft hub parts, overcoming the various high-precision form and position tolerances and high-precision machining surfaces of the crankshaft hub, realizing the related problems of turning instead of grinding, and avoiding the after-sales risks of product quality. The original horizontal ordinary chuck positioning turning processing, the workpiece linear speed is 110-150m / min, the feed speed is 0.02-0.035mm / r, the production cycle is 118 seconds, and the actual shift production is 184 pieces / shift; after using the clamping device of the present application, under the control of the preset program, the rough and fine machining workpiece linear speed can reach 300-360m / min, the feed speed is 0.05-0.08mm / r, the production cycle is increased to 58 seconds, and the actual shift production is 375 pieces / shift. While ensuring the stability and accuracy of the processing process, it effectively improves the manufacturing efficiency by 2.04 times, reduces the processing cost and the labor intensity of workers, and ensures the product quality requirements.

[0061] After the upgrade, 191 additional parts were processed per shift, each part costing 98 yuan, saving more than 1.016 million yuan in annual costs and 385,700 yuan in after-sales service costs. The clamping device of this application has a simple structure and is easy to operate. It can realize the fine processing of series parts through error-proof identification during the whole process, improve the surface processing accuracy of the workpiece, solve the technical problem of replacing grinding with turning for fine processing, and has great promotion value. At present, eight production lines of series wheel hubs have been horizontally deployed and applied synchronously.

[0062] The above shows and describes the basic principle, main features and advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments. The above embodiments and descriptions are only for explaining the principle of the utility model. The utility model may have various changes and improvements without departing from the spirit and scope of the utility model. These changes and improvements fall within the scope of the utility model to be protected. The scope of protection claimed by the utility model is defined by the attached claims and their equivalents.

Claims

1. A self-centering clamping device for an inverted lathe, characterized in that: include, A positioning assembly, the positioning assembly comprising a core shaft (1) and a positioning block (2); the positioning block (2) is an annular structure which is sleeved on the outside of the core shaft (1) and fixed coaxially with the core shaft (1); the lower end of the core shaft (1) protrudes from the shaft body of the positioning block (2) and is provided with a first conical surface which is smaller at the bottom and larger at the top; A clamping assembly, the clamping assembly comprising a flange pull rod (3) and an expansion sleeve (4); the flange pull rod (3) is a rod-shaped structure whose upper end is connected to a vertical driving device, and the flange pull rod (3) is coaxially arranged with the core shaft (1); the expansion sleeve (4) is an annular structure which is sleeved between the positioning block (2) and the core shaft (1) and coaxially arranged with the core shaft (1), and a second conical surface which is tightly fitted with the first conical surface is provided on the inner side of the lower end of the expansion sleeve (4), the upper end of the expansion sleeve (4) is fixedly connected to the flange pull rod (3), and the outer side of the lower end of the expansion sleeve (4) expands outwards to clamp the workpiece when the expansion sleeve (4) moves upward, and contracts inwards to release the clamping of the workpiece when the expansion sleeve (4) moves downward.

2. The self-centering clamping device for an inverted lathe according to claim 1, characterized in that: The lower end of the expansion sleeve (4) is provided with a plurality of partition grooves (5); the lower ends of the partition grooves (5) are flush with the lower end of the expansion sleeve (4); the partition grooves (5) penetrate the outer side surface and the inner side surface of the expansion sleeve (4); the plurality of partition grooves (5) are distributed at equal intervals along the circumferential direction with the axis of the expansion sleeve (4) as the center, and the lower part of the expansion sleeve (4) is evenly divided into a plurality of expansion blocks.

3. The self-centering clamping device for an inverted lathe according to claim 2, characterized in that: The partition groove (5) is filled with a filler.

4. The self-centering clamping device for an inverted lathe according to claim 1, characterized in that: A circle base (6) is arranged at the upper end of the expansion sleeve (4); a flange seat (7) is arranged at the upper end of the core shaft (1); the base (6) is fixedly connected to the flange plate (8) of the flange pull rod (3) by connecting bolts passing through the base (6) and the flange seat (7); a positioning sleeve (9) is sleeved on the connecting bolts; the positioning sleeve (9) is fixedly connected to the connecting bolts, and the upper and lower ends of the positioning sleeve (9) are respectively pressed against the flange plate (8) and the base (6).

5. The self-centering clamping device for an inverted lathe as claimed in claim 4, characterized in that: There are a plurality of positioning spacers (9), and the plurality of positioning spacers (9) are arranged at equal intervals along the circumferential direction with the axis of the expansion sleeve (4) as the center.

6. The self-centering clamping device for an inverted lathe according to claim 1, characterized in that: The lower end surface of the positioning block (2) is provided with a plurality of groups of positioning air holes (10), and the plurality of groups of positioning air holes (10) are arranged at equal intervals along the circumferential direction with the axis of the positioning block (2) as the center.

7. The self-centering clamping device for an inverted lathe according to claim 1, characterized in that: It also comprises a loading and unloading tray (11); the loading and unloading tray (11) is provided with a positioning ring (12) for fixing the workpiece during loading and a positioning pin (13) for fixing the workpiece during unloading.

8. The self-centering clamping device for an inverted lathe according to claim 1, characterized in that: It also includes a transition plate (14), which is an annular structure fixedly connected to the positioning block (2), and the inner cylindrical surface of the transition plate (14) is tightly fitted on the outer circumference of the flange plate (8) of the flange pull rod (3).

9. The self-centering clamping device for an inverted lathe according to claim 4, characterized in that: A guide hole is provided at the axial center position of the upper end of the flange seat (7); the lower end of the flange pull rod (3) is axially movably connected to the guide hole.

10. The self-centering clamping device for an inverted lathe according to claim 9, characterized in that: An O-type sealing ring (15) is arranged on the inner side of the guide hole.

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