Large connecting rod blank center surface positioning device and positioning method

Abstract

This invention relates to the technical field of positioning mechanisms, and in particular to a positioning device and method for the center surface of a large connecting rod blank. The device includes a frame, clamping units mounted on the frame for vertical positioning of the connecting rod body, and two fixed-axis units mounted on the frame for positioning two circular holes on the connecting rod body. The connecting rod body is horizontal, and the axes of the circular holes on the connecting rod body are vertical. By employing a unique three-set clamping group structure, utilizing the principle of non-collinear three points determining a single surface, and combining this with the principle of synchronous relative movement of two pressure rods within each clamping group to determine the center, three center points can be quickly positioned within the connecting rod body. The surface containing these three center points is the center surface of the connecting rod body. This method is simple, efficient, and enables rapid and precise positioning of the center surface of the connecting rod body.

Description

Technical Field

[0001] This invention relates to the technical field of positioning mechanisms, and in particular to a positioning device and method for the center surface of a large connecting rod blank. Background Technology

[0002] Connecting rod is a key core component of an engine. During operation, the connecting rod converts the reciprocating linear motion of the piston into the rotational motion of the crankshaft. Because the connecting rod is subjected to high pressure from the piston during operation, the compressive strength of the connecting rod body is required to be high. At the same time, if the effective width of the large and small holes at both ends of the connecting rod is not symmetrical with respect to the center plane of the rod body, the pressure on the cross-section of the rod body will be uneven, which may lead to bending. Therefore, there are precision requirements for the symmetry of the two sides of the large and small holes of the connecting rod with respect to the rod body. During the machining of the connecting rod, the center plane of the rod body is usually set as the positioning reference plane for the large and small holes. This means that the positioning accuracy of the center plane will directly affect the machining accuracy of the connecting rod.

[0003] The existing method for locating the center surface of a connecting rod involves placing the connecting rod horizontally, ensuring the axes of the large and small holes on both sides of the connecting rod are vertical, measuring the distance between the upper and lower surfaces of the connecting rod, and taking the midpoint of this distance as the center surface of the connecting rod. This center surface is then used as a reference for the next machining process, and subsequent connecting rods of the same type are machined according to the center surface determined in the first piece. However, due to the long length of the connecting rod and the varying thickness of different connecting rod blanks, the actual center surfaces of different blanks will differ, affecting the machining accuracy of the connecting rod. Measuring and locating the center surface of each connecting rod individually would be extremely time-consuming and labor-intensive, hindering workshop production efficiency. To address these issues, this invention provides a center surface positioning device and method for large connecting rod blanks. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides a positioning device and method for the center surface of a large connecting rod blank, the specific technical solution of which is as follows:

[0005] A large connecting rod blank center surface positioning device includes a frame, a clamping unit mounted on the frame for vertical positioning of the connecting rod body, and two fixed-axis units mounted on the frame for positioning two circular holes on the connecting rod body. The connecting rod body is horizontal, and the axis of the circular holes on the connecting rod body is vertical.

[0006] The clamping unit includes three clamping groups, which are coplanar on the horizontal plane and arranged in a triangle. Each clamping group includes a rack that moves laterally and gears located on the upper and lower sides of the rack that can mesh with the rack. Each gear is provided with a slanted arm, and each slanted arm is provided with a pressure rod.

[0007] In this setup, the movement trajectories of the three racks within the three sets of clamping groups are collinear, and the inclination directions of the two inclined arms within the clamping groups are symmetrical about the horizontal plane where the racks are located. The pressure rod is right-angled, with the horizontal part of the pressure rod used to connect with the inclined arms, and the vertical part of the pressure rod facing the connecting rod body and used to contact and press with the connecting rod body.

[0008] In the optimized implementation described above, a support sleeve is fitted on the horizontal portion of each pressure bar, the pressure bar rotates on the support sleeve, and the support sleeve is fixedly connected to the inclined arm;

[0009] Each pressure bar is equipped with a guide structure, which ensures that the vertical portion of the pressure bar remains vertical during movement.

[0010] In an optimized embodiment, each of the gears is provided with a support shaft, the gear rotates on the support shaft, and the support shaft is fixed on the frame;

[0011] The guide structure includes two synchronous pulleys fixed to the horizontal part of the support shaft and the pressure rod, and the two synchronous pulleys are connected by a synchronous belt drive.

[0012] In an optimized version of the above implementation, each of the pressure rods has a pressure plate at its vertical end, the pressure plate and the pressure rod are connected by a rotating ball, and the pressure rod is provided with a first spring for providing a restoring force to the pressure plate.

[0013] In an optimized version of the above implementation, the frame is provided with up to two first cylinders, and each first cylinder has a sliding table on its movable end that can slide on the frame. The sliding direction of the sliding table is parallel to the movement direction of the rack. The rack is slidably mounted on the sliding table, and the rack and the sliding table are connected by a leaf spring.

[0014] In an optimized version of the above implementation, the fixed-axis unit includes a vertical sleeve that slides vertically through the frame and a vertical shaft that slides vertically through the vertical sleeve. A movable disk is provided on the vertical shaft. Multiple sets of external support groups are provided between the vertical sleeve and the movable disk. The multiple sets of external support groups are arranged in a ring around the axis of the vertical sleeve. Each external support group consists of two external support rods. One external support rod is rotatably mounted on the movable disk, and the other external support rod is rotatably mounted on the vertical sleeve. The two external support rods are rotatably connected by a connecting shaft.

[0015] In an improved version of the above implementation, an auxiliary plate is rotatably fastened to the outside of the connecting shaft. The auxiliary plate is used to press the inner wall of the circular hole on the connecting rod body.

[0016] In the optimized implementation described above, the bottom of the vertical shaft extends beyond the vertical sleeve, the vertical shaft and the vertical sleeve are connected by a second spring, a limiting plate is provided at the bottom of the vertical shaft for limiting the position of the vertical shaft on the frame, and the frame and the vertical sleeve are connected by a second cylinder.

[0017] In an improved version of the above implementation, the frame is further provided with a locking unit for locking the positions of the three racks. The locking unit includes a U-shaped frame located outside the three racks. Both ends of the U-shaped frame slide through the frame. The sliding direction of the U-shaped frame is horizontal and perpendicular to the moving direction of the racks. The U-shaped frame is connected to the frame via a third cylinder.

[0018] The method for locating the center surface of a large connecting rod blank includes the following steps:

[0019] S1. The moving disk is moved down to the initial position by the second cylinder on the fixed axis unit;

[0020] S2. The rack is moved by the first cylinder to separate the two pressure rods in the clamping assembly.

[0021] S3. Place the connecting rod body on the three pressure plates below the reference plane in the three sets of clamping groups. The three pressure plates support the connecting rod body.

[0022] S4. The first cylinder brings the two pressure rods closer to each other and uses the pressure plate to clamp the upper and lower surfaces of the connecting rod body. At this time, the clamping group completes the positioning of one center point on the connecting rod body. The three clamping groups position the three center points on the connecting rod body, thereby determining the position of the center surface of the connecting rod body through the three center points.

[0023] S5. The second cylinder on the fixed axis unit controls multiple sets of external support groups to move into the circular hole of the connecting rod body and uses the synchronous outward extension of multiple sets of external support groups to fix the circular hole and perform fixed axis work. The two sets of fixed axis units simultaneously position the two circular holes on the connecting rod body.

[0024] S6. When the connecting rod body is offset on the horizontal plane due to the positioning of the fixed axis unit, the connecting rod body slides relative to the pressure plate. When the connecting rod body stops moving, the locking unit locks the position of the rack on the three sets of clamping groups. At this time, the position of the connecting rod body and the position of its upper center surface are fixed.

[0025] The advantages of this invention are:

[0026] By employing a unique three-clamp assembly structure, utilizing the principle of non-collinear three points determining a surface, and combining this with the principle of synchronous relative motion of two pressure rods within each clamp assembly to determine the center, three center points can be quickly located within the connecting rod body. The surface containing these three center points is the center surface of the connecting rod body. This method is simple and efficient, enabling rapid and accurate positioning of the center surface of the connecting rod body. It avoids the time-consuming process of measuring the center surface of each connecting rod body one by one in the traditional method, thus improving production efficiency. Furthermore, it avoids the problem of inaccurate center surface positioning caused by the shape differences of different connecting rod bodies when only the first connecting rod body is measured and subsequent connecting rod bodies are directly positioned based on this reference.

[0027] Since the positioning is done by directly positioning the center point, even if the upper and lower surfaces of the connecting rod body are tilted, it will not affect the positioning accuracy. This ensures the accuracy of the positioning of the center surface of the connecting rod body and reduces the positioning error caused by the difference in length and thickness of the connecting rod body, thus improving the machining accuracy of the connecting rod body. At the same time, even if the lengths of the vertical parts of the pressure rods in the three sets of clamping groups are not consistent, the positioning work can still be achieved as long as the lengths of the vertical parts of the two pressure rods in each set of clamping groups are consistent.

[0028] By combining upper and lower positioning with circular hole positioning, it can flexibly adapt to the center surface positioning requirements of different connecting rod body blanks.

[0029] By adjusting the lateral movement of the rack, automatic centering of the connecting rod body can be achieved, simplifying the operation process and facilitating its application in actual production. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the structure of the present invention;

[0032] Figure 2 yes Figure 1 Left-view structural diagram;

[0033] Figure 3 yes Figure 1 Explosion structure diagram;

[0034] Figure 4 yes Figure 3 Enlarged structural diagram of the middle clamp unit;

[0035] Figure 5 yes Figure 4 A magnified schematic diagram of the left side of the clamping assembly;

[0036] Figure 6 yes Figure 3 Enlarged cross-sectional view of the central axis unit;

[0037] Marked in the attached diagram:

[0038] 100. Rack;

[0039] 200. Clamping unit; 201. Rack; 202. Gear; 203. Slanted arm; 204. Pressure rod; 205. Support sleeve; 206. Support shaft; 207. Synchronous pulley; 208. Synchronous belt; 209. Pressure plate; 210. First spring; 211. Slide table; 212. Leaf spring; 213. First cylinder;

[0040] 300. Fixed axis unit; 301. Vertical sleeve; 302. Vertical shaft; 303. Moving disk; 304. External support rod; 305. Connecting shaft; 306. Auxiliary plate; 307. Second spring; 308. Limiting plate; 309. Second cylinder;

[0041] 400. Connecting rod body;

[0042] 500, Locking unit; 501, U-shaped frame; 502, Third cylinder. Detailed Implementation

[0043] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0044] In the description of this invention, it should be noted that the orientations or positional relationships indicated by terms such as "center", "up", "down", "left", "right", "vertical", "horizontal", "inner", and "outer" are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0045] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. This embodiment is written in a progressive manner.

[0046] like Figures 1 to 5 As shown, the large connecting rod blank center surface positioning device of the present invention includes a frame 100, a clamping unit 200 disposed on the frame 100 for vertical positioning of the connecting rod body 400, and two fixed axis units 300 disposed on the frame 100 for positioning two circular holes on the connecting rod body 400. The connecting rod body 400 is horizontal, and the axis of the circular holes on the connecting rod body 400 is vertical.

[0047] The clamping unit 200 includes three clamping groups. The three clamping groups are coplanar on the horizontal plane and are distributed in a triangle. Each clamping group includes a rack 201 that moves laterally and gears 202 located on the upper and lower sides of the rack 201 and capable of meshing with the rack 201. Each gear 202 is provided with a slanted arm 203 and each slanted arm 203 is provided with a pressure rod 204.

[0048] Among them, the movement trajectories of the three racks 201 in the three sets of clamping groups are collinear, and the inclination directions of the two inclined arms 203 in the clamping groups are symmetrical about the horizontal plane where the racks 201 are located. The shape of the pressure rod 204 is right-angled. The horizontal part of the pressure rod 204 is used to connect with the inclined arm 203, and the vertical part of the pressure rod 204 faces the connecting rod body 400 and is used to contact and press with the connecting rod body 400.

[0049] In detail, the connecting rod body 400 consists of a long rod in the middle and two round hole parts at both ends of the long rod. The two round hole parts are large and small holes. The clamping unit 200 is used to center and position the horizontal center plane of the connecting rod body 400. The two fixed axis units 300 are used to position the two round hole parts on the left and right sides of the connecting rod body 400. The frame 100 is used to support the clamping unit 200 and the fixed axis units 300.

[0050] Since the clamping unit 200 consists of three clamping groups, which are coplanar on the horizontal plane and arranged in a triangle, the plane determination of the connecting rod body 400 can be achieved by using three non-collinear points to determine a plane. However, if four or more clamping groups are used, some clamping groups may fail to contact the connecting rod body 400, or the planes determined by multiple clamping groups may not be unique. Because the rack 201 in the clamping group meshes with the two gears 202 on its upper and lower sides, when the rack 201 moves laterally, it can drive the two gears 202 to rotate synchronously in opposite directions. The two gears 202 will carry the two inclined arms 203 to rotate synchronously in opposite directions. Rotation occurs, causing the two pressure rods 204 to move synchronously relative to each other. The midpoint of the line connecting the two pressure rods 204 remains constant. Thus, when the two pressure rods 204 contact the upper and lower surfaces of the connecting rod body 400, the midpoint of the line connecting the two pressure rods 204 becomes a point on the center plane of the connecting rod body 400. This point is simultaneously on the same horizontal plane as the movement trajectory of the rack 201. By directly locating the center point and using three sets of clamping assemblies, three center points can be determined on the center plane of the connecting rod body 400. The center plane of the connecting rod body 400 can then be determined by passing through these three center points, thereby achieving rapid and direct positioning of the center plane of the connecting rod body 400.

[0051] The three pressure bars 204 on the upper side of the reference surface can determine the upper surface of the connecting rod body 400, and the three pressure bars 204 on the lower side of the reference surface can determine the lower surface of the connecting rod body 400. Even if the determined surface is tilted, it will not affect the position of the center point determined by the clamping group, and therefore will not affect the center surface of the connecting rod body 400. This can greatly improve the positioning accuracy.

[0052] By employing a unique three-set clamping structure, utilizing the principle of non-collinear three-point positioning of a single surface, and combining this with the principle of synchronous relative motion of two pressure rods 204 within each clamping set to determine the center, three center points can be quickly located within the connecting rod body 400. The surface containing these three center points is the center surface of the connecting rod body 400. This method is simple and efficient, enabling rapid and precise positioning of the center surface of the connecting rod body 400. It avoids the time-consuming process of measuring the center surface of each connecting rod body 400 individually in traditional methods, thus improving production efficiency. Furthermore, it avoids the problem of inaccurate center surface positioning caused by shape differences in different connecting rod bodies 400 when only the first connecting rod body 400 is measured and subsequent connecting rod bodies 400 are directly positioned using this as a reference. Because the positioning uses direct positioning... The centering method ensures that even if the upper and lower surfaces of the connecting rod body 400 are tilted, it will not affect the positioning accuracy, thus ensuring the accuracy of the center plane positioning of the connecting rod body 400. It also reduces the positioning error caused by the difference in length and thickness of the connecting rod body 400, and improves the machining accuracy of the connecting rod body 400. At the same time, even if the vertical parts of the pressure rods 204 in the three sets of clamping groups are not the same length, the positioning work can still be achieved as long as the lengths of the vertical parts of the two pressure rods 204 in each set of clamping groups are the same. Through the combination of upper and lower positioning and circular hole positioning, it can flexibly adapt to the center plane positioning requirements of different connecting rod body 400 blanks. By adjusting the lateral movement of the rack 201, the automatic centering of the connecting rod body 400 can be achieved, simplifying the operation process and facilitating its promotion and application in actual production.

[0053] like Figure 5 As shown, each of the horizontal portions of the pressure rod 204 is fitted with a support sleeve 205, the pressure rod 204 rotates on the support sleeve 205, and the support sleeve 205 is fixedly connected to the inclined arm 203.

[0054] Each pressure rod 204 is provided with a guide structure, which is used to ensure that the vertical part of the pressure rod 204 remains vertical when it moves.

[0055] In detail, since the movement of the pressure rod 204 is powered by the rotation of the gear 202, the movement trajectory of the pressure rod 204 is arc-shaped. That is, the gear 202 drives the pressure rod 204 to move in an arc shape around the axis of the gear 202 via the inclined arm 203 and the support sleeve 205, thereby adjusting the positional relationship between the pressure rod 204 and the connecting rod body 400. However, when the pressure rod 204 moves in an arc shape, the direction of the vertical part of the pressure rod 204 will change. At this time, the vertical part of the pressure rod 204 will not... To avoid this phenomenon, the vertical connecting rod body 400 is supported by the support sleeve 205 and the guide structure is used to guide the pressure rod 204, so that the vertical part of the pressure rod 204 is always vertical. This makes it easy for the pressure rod 204 to press and position the connecting rod body 400 smoothly. At the same time, when it is necessary to position the connecting rod body 400 of different thicknesses, the vertical part of the pressure rod 204 can still remain perpendicular to the connecting rod body 400, thus improving the adaptability and functionality of the equipment.

[0056] like Figure 5 As shown, each gear 202 is provided with a support shaft 206, the gear 202 rotates on the support shaft 206, and the support shaft 206 is fixed on the frame 100;

[0057] The guide structure includes two synchronous pulleys 207 fixed to the horizontal part of the support shaft 206 and the pressure rod 204, and the two synchronous pulleys 207 are connected by a synchronous belt 208.

[0058] In detail, gear 202 is mounted on frame 100 via support shaft 206 and can rotate on support shaft 206. Support shaft 206 and its synchronous pulley 207 are both in a fixed state. Pressure rod 204 and its synchronous pulley 207 are relatively stationary. When gear 202 rotates and drives pressure rod 204 to tilt, pressure rod 204 drives synchronous pulley 207 to move synchronously. Since synchronous pulley 207 on support shaft 206 is fixed, synchronous pulley 207 on pressure rod 204 will drive synchronous belt 208 to move around synchronous pulley 207 on support shaft 206. Synchronous pulley 207 on support shaft 206 pulls synchronous pulley 207 on pressure rod 204 to rotate in the opposite direction relative to support sleeve 205 via synchronous belt 208. At this time, pressure rod 204 rotates in the opposite direction relative to support sleeve 205, so that the direction of pressure rod 204 remains unchanged. Pressure rod 204 follows support sleeve 205 to perform arc-shaped translational movement.

[0059] like Figure 5 As shown, each of the pressure rods 204 has a pressure plate 209 at the vertical end. The pressure plate 209 is connected to the pressure rod 204 by a rotating ball. The pressure rod 204 is provided with a first spring 210 for providing a restoring force to the pressure plate 209.

[0060] In detail, since the pressure plate 209 and the pressure rod 204 are connected by a rotating ball, the pressure plate 209 can tilt in any direction on the pressure rod 204. When the pressure rod 204 presses the upper or lower surface of the connecting rod body 400 through the pressure plate 209, the pressure plate 209 can be parallel to the upper or lower surface of the connecting rod body 400, so that the pressure plate 209 automatically adapts to the connecting rod body 400. Because of the use of the pressure plate 209, the pressure rod 204 and the connecting rod body 400 can be in surface contact, avoiding the pressure dents on the connecting rod body 400 caused by the pressure rod 204 directly pressing the connecting rod body 400 and affecting the quality of the connecting rod body 400. This facilitates the protection of the connecting rod body 400. By setting the first spring 210, the pressure plate 209 can be easily reset to horizontal on the pressure rod 204.

[0061] like Figures 4 to 5 As shown, the frame 100 is provided with up to two first cylinders 213. Each first cylinder 213 is provided with a slide 211 that can slide on the frame 100. The sliding direction of the slide 211 is parallel to the movement direction of the rack 201. The rack 201 is slidably mounted on the slide 211. The rack 201 and the slide 211 are connected by a leaf spring 212.

[0062] In detail, when the inclination directions of the pressure plates 209 on the same side of the reference plane in the three sets of clamping groups are the same, the movement mode of the three sets of clamping groups is consistent. Only one first cylinder 213 and one slide table 211 are needed. The three racks 201 are slidably mounted on the slide table 211. When it is necessary to position the connecting rod body 400, the extension and retraction movement of the first cylinder 213 pushes the slide table 211 to move, thereby moving the rack 201 with the help of the leaf spring 212 on each rack 201. This provides power to each rack 201, so that the pressure rod 204 positions and presses the connecting rod body 400. When the pressure rod 204 in part of the clamping group is fully positioned on the connecting rod body, the pressure rod 204 can be used to position and press the connecting rod body 400. When the body 400 is compressed, the pressure rod 204 in the remaining clamping group is still not in contact with the connecting rod body 400. At this time, the slide table 211 can continue to move. The clamping group that has completed the compression work no longer moves, and the leaf spring 212 on the clamping group undergoes elastic deformation. The clamping group that has not completed the compression work continues to run until the compression work is completed. In this way, the first cylinder 213 can supply power to the three clamping groups. Even if the three clamping groups clamp the connecting rod body 400 one after another, the first cylinder 213 can still provide power to it and will not affect the positioning accuracy of the center surface. The structure is simple and the operation is convenient. There is no need to set power for each clamping group and operate it independently.

[0063] When the inclination directions of the pressure plates 209 located on the same side of the reference plane in the three clamping groups are different, the inclination directions of the pressure plates 209 in the two clamping groups are the same, and the inclination direction of the pressure plates 209 in the remaining clamping group is opposite to the inclination direction of the pressure plates 209 in the other clamping groups. At this time, two first cylinders 213 and two slides 211 can be used. One first cylinder 213 and its slide 211 can provide power to two clamping groups, and the other first cylinder 213 and its slide 211 can provide power to the remaining clamping group.

[0064] like Figure 6 As shown, the fixed-axis unit 300 includes a vertical sleeve 301 that slides vertically through the frame 100 and a vertical shaft 302 that slides vertically through the vertical sleeve 301. A movable disk 303 is provided on the vertical shaft 302. Multiple sets of external support groups are provided between the vertical sleeve 301 and the movable disk 303. The multiple sets of external support groups are arranged in a ring around the axis of the vertical sleeve 301. Each external support group consists of two external support rods 304. One external support rod 304 is rotatably mounted on the movable disk 303, and the other external support rod 304 is rotatably mounted on the vertical sleeve 301. The two external support rods 304 are rotatably connected by a connecting shaft 305.

[0065] In detail, the two outer support rods 304 in the outer support assembly are in a relatively inclined state. When the vertical sleeve 301 and the vertical shaft 302 move relative to each other, the distance between the moving disk 303 and the vertical sleeve 301 changes. At this time, the moving disk 303 and the vertical sleeve 301 squeeze the two outer support rods 304 and move synchronously. Since the two outer support rods 304 are rotatably connected by the connecting shaft 305, the distance between the connecting shaft 305 and the axis of the vertical sleeve 301 changes, thereby adjusting the outward extension distance of the outer support assembly. Multiple sets of outer support assemblies move simultaneously. When it is necessary to position the circular hole on the connecting rod body 400, multiple sets of outer support assemblies are located inside the circular hole. At this time, the vertical sleeve 301 and the vertical shaft 302 move relative to each other, and multiple sets of outer support assemblies extend outward synchronously and contact the inner wall of the circular hole. At this time, multiple sets of outer support assemblies perform external support and fixation work on the circular hole, and the position of the axis of the circular hole is positioned.

[0066] like Figure 6 As shown, an auxiliary plate 306 is rotatably fastened to the outside of the connecting shaft 305. The auxiliary plate 306 is used to press the inner wall of the circular hole on the connecting rod body 400.

[0067] In detail, when the outer support assembly compresses the inner wall of the 400-round hole in the connecting rod body, the area of ​​action of the outer support assembly on the inner wall of the round hole is relatively small. By using the auxiliary plate 306, the area of ​​action can be increased, thereby protecting the round hole.

[0068] In actual use, since the connecting rod body 400 is a blank part when it is positioned, the round hole on the connecting rod body 400 has not been precision machined and its accuracy has not yet met the specified requirements. At this time, when the clamping unit 200 positions the connecting rod body 400, the round hole on the connecting rod body 400 will be slightly tilted, and the auxiliary plate 306 cannot be kept vertical. Therefore, it is necessary to rotate the auxiliary plate 306 on the connecting shaft 305 to adapt to the positioning work of the round hole under this condition.

[0069] like Figure 6 As shown, the bottom of the vertical shaft 302 extends beyond the vertical sleeve 301. The vertical shaft 302 and the vertical sleeve 301 are connected by a second spring 307. The bottom of the vertical shaft 302 is provided with a limiting plate 308 for limiting the position of the vertical shaft 302 on the frame 100. The frame 100 and the vertical sleeve 301 are connected by a second cylinder 309.

[0070] In detail, the second spring 307 is used to connect the vertical sleeve 301 and the vertical shaft 302. In its natural state, the moving plate 303 is close to the upper surface of the frame 100. At this time, there is a large space above the moving plate 303 to facilitate the disassembly and assembly of the connecting rod body 400. After the clamping unit 200 initially positions the connecting rod body 400, the second cylinder 309 retracts and drives the vertical sleeve 301 to move upward. At this time, due to the action of the second spring 307, the vertical shaft 302 moves upward synchronously, and multiple sets of external supports move from below the connecting rod body 400 to the connecting rod. Inside the circular hole of the main body 400, the limiting plate 308 is in contact with the bottom of the frame 100. The limiting plate 308 drives the vertical shaft 302 to stop moving, the moving disk 303 stops moving, the second cylinder 309 continues to retract and pushes the vertical sleeve 301 to move, the distance between the vertical sleeve 301 and the moving disk 303 is shortened, thereby providing power for the deformation movement of the outer support assembly. This structure can realize the adjustment of the position of the fixed axis unit 300, which provides sufficient space for the disassembly and assembly of the connecting rod body 400, and can also provide power for the deformation of the outer support assembly.

[0071] In actual operation, if the clamping unit 200 completes the positioning of the connecting rod body 400, the circular hole on the connecting rod body 400 will be offset from the fixed axis unit 300. When the fixed axis unit 300 is used to position the circular hole again, the connecting rod body 400 will move on the horizontal plane until the axis of the circular hole coincides with the axis of the vertical sleeve 301. At this time, the connecting rod body 400 will slide on the pressure plate 209.

[0072] like Figures 2 to 4As shown, the frame 100 is also provided with a locking unit 500 for locking the positions of the three racks 201. The locking unit 500 includes a U-shaped frame 501 located outside the three racks 201. Both ends of the U-shaped frame 501 slide through the frame 100. The sliding direction of the U-shaped frame 501 is horizontal and perpendicular to the moving direction of the racks 201. The U-shaped frame 501 is connected to the frame 100 through a third cylinder 502.

[0073] In detail, when the rack 201 stops moving, the center plane positioning of the connecting rod body 400 is completed. At this time, the third cylinder 502 pushes the U-shaped frame 501 to move on the frame 100. The U-shaped frame 501 approaches the rack 201 and rubs and squeezes the rack 201 to fix it, thereby locking the position of the rack 201. At this time, the position of the center plane of the connecting rod body 400 is locked.

[0074] The method for locating the center surface of a large connecting rod blank includes the following steps:

[0075] S1. The moving disk 303 is moved down to the initial position by the second cylinder 309 on the fixed axis unit 300;

[0076] S2. The rack 201 is moved by the first cylinder 213 to separate the two pressure rods 204 in the clamping assembly.

[0077] S3. Place the connecting rod body 400 on the three pressure plates 209 below the reference plane of the three sets of clamping groups. The three pressure plates 209 support the connecting rod body 400.

[0078] S4. The first cylinder 213 brings the two pressure rods 204 closer to each other and uses the pressure plate 209 to clamp the upper and lower surfaces of the connecting rod body 400. At this time, the clamping group completes the positioning of one center point on the connecting rod body 400. The three clamping groups position the three center points on the connecting rod body 400, thereby determining the position of the center surface of the connecting rod body 400 through the three center points.

[0079] S5. The second cylinder 309 on the fixed axis unit 300 controls multiple sets of external support groups to move into the circular hole of the connecting rod body 400 and uses the synchronous outward extension of multiple sets of external support groups to fix and fix the circular hole. The two sets of fixed axis units 300 simultaneously position the two circular holes on the connecting rod body 400.

[0080] S6. When the connecting rod body 400 is offset on the horizontal plane due to the positioning of the fixed axis unit 300, the connecting rod body 400 slides relative to the pressure plate 209. When the connecting rod body 400 stops moving, the locking unit 500 locks the position of the rack 201 on the three sets of clamping groups. At this time, the position of the connecting rod body 400 and the position of its center surface are fixed.

[0081] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A positioning device for the center surface of a large connecting rod blank, characterized in that, It includes a frame, a clamping unit mounted on the frame for vertical positioning of the connecting rod body, and two fixed-axis units mounted on the frame for positioning two circular holes on the connecting rod body. The connecting rod body is horizontal, and the axis of the circular holes on the connecting rod body is vertical. The clamping unit includes three clamping groups, which are coplanar on the horizontal plane and arranged in a triangle. Each clamping group includes a rack that moves laterally and gears located on the upper and lower sides of the rack that can mesh with the rack. Each gear is provided with a slanted arm, and each slanted arm is provided with a pressure rod. Among them, the movement trajectories of the three racks in the three sets of clamping groups are collinear, the inclination directions of the two inclined arms in the clamping groups are symmetrical about the horizontal plane where the racks are located, the shape of the pressure rod is right angle, the horizontal part of the pressure rod is used to connect with the inclined arm, and the vertical part of the pressure rod faces the connecting rod body and is used to contact and squeeze with the connecting rod body. Each of the horizontal portions of the pressure bar is fitted with a support sleeve, the pressure bar rotates on the support sleeve, and the support sleeve is fixedly connected to the inclined arm; Each pressure bar is equipped with a guide structure, which is used to ensure that the vertical part of the pressure bar remains vertical when it moves. Each of the gears is provided with a support shaft, the gear rotates on the support shaft, and the support shaft is fixed on the frame; The guide structure includes two synchronous pulleys fixed to the horizontal part of the support shaft and the pressure rod, and the two synchronous pulleys are connected by a synchronous belt drive. Each of the pressure rods has a pressure plate at the vertical end, and the pressure plate is connected to the pressure rod by a rotating ball. The pressure rod is provided with a first spring for providing a restoring force to the pressure plate. The fixed-axis unit includes a vertical sleeve that slides vertically through the frame and a vertical shaft that slides vertically through the vertical sleeve. A movable disk is provided on the vertical shaft. Multiple sets of external support groups are provided between the vertical sleeve and the movable disk. The multiple sets of external support groups are arranged in a ring around the axis of the vertical sleeve. Each external support group consists of two external support rods. One external support rod is rotatably mounted on the movable disk, and the other external support rod is rotatably mounted on the vertical sleeve. The two external support rods are rotatably connected by a connecting shaft.

2. The large connecting rod blank center surface positioning device according to claim 1, characterized in that, The frame is provided with up to two first cylinders. Each first cylinder has a sliding table on its movable end that can slide on the frame. The sliding direction of the sliding table is parallel to the movement direction of the rack. The rack is slidably mounted on the sliding table and is connected to the sliding table by a leaf spring.

3. The center plane positioning device for large connecting rod blanks of claim 2 wherein, An auxiliary plate is rotatably fastened to the outside of the connecting shaft. The auxiliary plate is used to press the inner wall of the circular hole on the connecting rod body.

4. The center plane positioning device for large connecting rod blanks of claim 3 wherein, The bottom of the vertical shaft extends beyond the vertical sleeve. The vertical shaft and the vertical sleeve are connected by a second spring. The bottom of the vertical shaft is provided with a limiting plate for limiting the position of the vertical shaft on the frame. The frame and the vertical sleeve are connected by a second cylinder.

5. The center plane positioning device for large connecting rod blanks of claim 4 wherein, The frame is also equipped with a locking unit for locking the positions of the three racks. The locking unit includes a U-shaped frame located outside the three racks. Both ends of the U-shaped frame slide through the frame. The sliding direction of the U-shaped frame is horizontal and perpendicular to the moving direction of the racks. The U-shaped frame is connected to the frame by a third cylinder.

6. A method for locating the center surface of a large connecting rod blank, applicable to the center surface positioning device for a large connecting rod blank as described in claim 5, characterized in that, Includes the following steps: S1. The moving disk is moved down to the initial position by the second cylinder on the fixed axis unit; S2. The rack is moved by the first cylinder to separate the two pressure rods in the clamping assembly. S3. Place the connecting rod body on the three pressure plates below the reference plane in the three sets of clamping groups. The three pressure plates support the connecting rod body. S4. The first cylinder brings the two pressure rods closer to each other and uses the pressure plate to clamp the upper and lower surfaces of the connecting rod body. At this time, the clamping group completes the positioning of one center point on the connecting rod body. The three clamping groups position the three center points on the connecting rod body, thereby determining the position of the center surface of the connecting rod body through the three center points. S5. The second cylinder on the fixed axis unit controls multiple sets of external support groups to move into the circular hole of the connecting rod body and uses the synchronous outward extension of multiple sets of external support groups to fix the circular hole and perform fixed axis work. The two sets of fixed axis units simultaneously position the two circular holes on the connecting rod body. S6. When the connecting rod body is offset on the horizontal plane due to the positioning of the fixed axis unit, the connecting rod body slides relative to the pressure plate. When the connecting rod body stops moving, the locking unit locks the position of the rack on the three sets of clamping groups. At this time, the position of the connecting rod body and the position of its upper center surface are fixed.

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