An online diameter measuring device for large free forgings

Abstract

The present invention relates to the field of crankshaft measurement technology, specifically an online diameter measurement device for large free forgings, comprising a mounting plate for use with the crankshaft, a follower assembly, a positioning roller, a laser measuring instrument, and a synchronization assembly. The follower assembly is disposed on the mounting plate and is provided in two groups, each group having two members. The positioning roller is disposed on the follower assembly, the laser measuring instrument is disposed on the follower assembly, and two synchronization assemblies are provided. Each synchronization assembly has two ends connected to a corresponding follower assembly. Before measurement, the synchronization assembly is pulled and moved in a direction perpendicular to the axis of the crankshaft's main journal. By providing the follower assembly, synchronization assembly, and positioning roller, the present invention can achieve stable contact between the positioning roller and the surface of the connecting rod journal being measured when the crankshaft axis is not offset or the offset is small, thereby ensuring the accuracy of the measurement results.

Description

Technical Field

[0001] The invention relates to the technical field of crankshaft measurement, in particular to an online diameter measurement device for large free forgings. Background Art

[0002] A free forging is a metal forging produced by free forging. In the manufacturing of automotive parts, free forging is often used to produce gears and shaft components. The crankshaft is the most important component in a car engine. During operation, it converts the pressure transmitted from each piston assembly into torque, thereby driving the normal driving of the car.

[0003] During the crankshaft manufacturing process, the diameter of the connecting rod journal needs to be measured to avoid large deviations in the connecting rod journal diameter accuracy, which could cause severe wear on components such as the connecting rod and piston during operation, thereby affecting engine performance. The traditional measurement method uses an outside micrometer and manual sampling to measure the connecting rod journal diameter (taking the commonly used economy cars on the market as an example, most of them use four-cylinder engines, that is, the crankshaft used in the engine contains four connecting rod journals). Due to the mass production of crankshafts in the production workshop, measurement efficiency is limited, and the measurement results are largely affected by the work experience of the staff. The accuracy of the measurement results cannot be effectively guaranteed, which may cause the crankshaft to affect engine performance during subsequent use. In response to the above problems, there are good solutions in the existing technology, such as the four-axis linkage tracking crankshaft measurement method with patent number: CN105333828B. It adopts a four-axis tracking linkage motion structure, equipped with a follow-up feed probe device and sets a corresponding number of follow-up probes according to the number of connecting rod journals. During the rotation of the crankshaft, the linkage work of each axis is utilized to realize automatic measurement of the diameter of each connecting rod journal. While improving the measurement efficiency, it can also ensure measurement accuracy, thereby ensuring the performance of the engine during subsequent use. However, the following drawbacks still exist: Because the measurement process requires a fixture to clamp both ends of the crankshaft and then drive it to rotate around the crankshaft's main journal, the fixture needs to be frequently used to clamp the two ends of the crankshaft to be measured during mass production in the factory. The jaws in the fixture, which are used for a long time, will wear against different crankshaft surfaces during each crankshaft installation, causing the two ends of the crankshaft to deviate from the axis after being clamped. (For example, in a three-jaw chuck, the front and back jaws will wear unevenly after long-term use, causing the jaws to become flared, resulting in the workpiece deviating from the center of the lathe spindle after the three-jaw chuck is clamped.) During the measurement process, because the fixture drives the crankshaft to continuously rotate, when the crankshaft's main journal axis deviates, the entire crankshaft will oscillate simultaneously in the XOY, XOZ, and YOZ planes. The oscillation amplitude at the end positions is greater than that at the middle position, resulting in the follower probe being unable to maintain stable contact with the surface of the connecting rod journal being measured on the crankshaft, which also affects the measurement results and still cannot effectively guarantee the performance of the engine during subsequent use.

[0004] Therefore, in order to solve the above problems, an online diameter measuring device for large free forgings is proposed. Summary of the Invention

[0005] The present invention provides an online diameter measurement device for large open-die forgings. This device addresses the problem of frequent fixture-assisted measurement during factory mass production, where fixture wear can cause the main axis of the crankshaft to deviate after clamping, thereby affecting the accuracy of measurement results and, consequently, failing to effectively guarantee engine performance during subsequent use of the crankshaft. By providing a follower assembly, a synchronizing assembly, and positioning rollers, two sets of positioning rollers can be simultaneously pulled directly above the connecting rod journal being measured before measurement, effectively simplifying the measurement process during factory mass production. Furthermore, when fixture wear causes the axis of the crankshaft's main journal to deviate, the follower assembly provides the rollers with horizontal and vertical rotational freedom. This ensures that even when the crankshaft's main journal axis is slightly offset or not offset, the rollers maintain stable contact with the corresponding connecting rod journal surface, thereby ensuring accurate measurement results and, consequently, ensuring engine performance during subsequent use. Furthermore, a pressure sensor in the follower assembly can determine the impact of other factors on crankshaft quality, further guaranteeing engine performance.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A diameter online measuring device for large free forgings includes a mounting plate for use with a crankshaft, a follower assembly, a positioning roller, a laser measuring instrument and a synchronization assembly, wherein the follower assembly is arranged on the mounting plate and is provided with two groups, each group is provided with two, the positioning roller is arranged on the follower assembly, the laser measuring instrument is arranged on the follower assembly, and the synchronization assembly is provided with two, and the two ends of each synchronization assembly are respectively connected to the corresponding follower assembly. Before measurement, the synchronization assembly is pulled to move in a direction perpendicular to the axis of the main journal of the crankshaft. When the synchronization assembly moves, the corresponding two positioning rollers are driven to the two sides of the axis of the connecting rod journal of the crankshaft through the follower assembly. During measurement, the mounting plate moves down and drives the two positioning rollers down to fit the surface of the connecting rod journal of the crankshaft through the follower assembly. When the crankshaft rotates, the positioning roller remains in fit with the connecting rod journal of the crankshaft.

[0008] Preferably, the follower assembly includes a U-shaped rod, a slider, an elastic telescopic rod, a connecting piece, a U-shaped frame, an electric guide rail and a U-shaped plate. The U-shaped rod is arranged on the mounting plate and the horizontal section is arranged perpendicular to the axis of the crankshaft. The slider is arranged on the U-shaped rod, the elastic telescopic rod is arranged on the slider, the connecting piece is arranged on the elastic telescopic rod, the U-shaped frame is arranged on the elastic telescopic rod, the electric guide rail and the U-shaped plate are both arranged on the U-shaped frame, the laser measuring instrument is arranged on the electric guide rail, and the positioning roller is arranged inside the U-shaped plate. When the axis of the crankshaft is offset, the positioning roller remains in contact with the connecting rod journal of the crankshaft through the connecting piece.

[0009] It can be seen that in the working state of mass production of crankshafts in the factory, the diameter of the connecting rod journal of the crankshaft needs to be measured frequently using a fixture to ensure that the crankshaft can rotate on its own main journal during the measurement process. Frequent use will cause the fixture to wear, causing the axis of the crankshaft to shift after the fixture clamps the crankshaft. As a result, during the measurement process, the distance between the laser measuring instrument and the connecting rod journal of the crankshaft will dynamically change due to the rotation of the crankshaft, thereby affecting the measurement results. Therefore, this solution is adopted. By setting the elastic telescopic rod and the connecting piece, the positioning roller can be stably fitted with the surface of the connecting rod journal of the crankshaft when the axis of the crankshaft is not offset, so as to ensure the accuracy of the measurement result. When the axis of the crankshaft is offset but the offset is small, the elastic force of the elastic telescopic rod and the rotational freedom provided to the pressure roller in the horizontal and vertical directions by the connecting piece can also ensure the fit of the pressure roller and the connecting rod journal of the crankshaft, thereby ensuring the accuracy of the measurement result. When the axis offset of the crankshaft is large and the positioning roller cannot stably fit with the surface of the connecting rod journal of the crankshaft, since the swing amplitude of the end of the crankshaft is greater than the swing amplitude of the middle part, the measurement results of each laser measuring instrument will be different, and the measurement results will differ greatly, which can objectively reflect that the fixture is worn and the fixture needs to be repaired or replaced to ensure the accuracy of subsequent measurement results.

[0010] Preferably, the synchronization component includes two fixing frames, two U-shaped rods II, a connecting rod, a spring, a baffle and a pressure sensor. A strip opening is opened on the mounting plate, the fixing frame passes through the strip opening and is connected to the slider, the open end of the U-shaped rod II is hinged to the fixing frame, the connecting rod passes through the closed end of one of the U-shaped rods II and is connected to the closed end of the other U-shaped rod II, the baffle is sleeved on the connecting rod and is located inside the corresponding U-shaped rod II, the spring is arranged between the connecting rod and the baffle and sleeved on the connecting rod, and the pressure sensor is arranged on the inner wall of the closed end of the corresponding U-shaped rod II.

[0011] It can be seen that there are many ways to judge the quality of a crankshaft, including whether the two connecting rod journals at the end and middle positions of the crankshaft are collinear. The conventional judgment method is to test them separately. Considering that separate testing is time-consuming and affects work efficiency during factory batch production, this solution is adopted. Through the synchronization component, the two laser measuring instruments at the end and middle positions can be synchronously pulled to the top of the corresponding connecting rod journals of the crankshaft before measurement, simplifying the work steps before the measurement operation. In addition, when the axes of the two connecting rod journals at the end or middle positions of the crankshaft are not collinear, the pressure change of the pressure sensor can be used to judge whether the crankshaft is qualified, avoiding the quality of the crankshaft being affected by the qualified diameter of the connecting rod journal but unqualified in other aspects.

[0012] Preferably, the connecting member includes a connecting plate, a rotating rod, a fixed block and a movable block, the connecting plate is arranged at the lower end of the elastic telescopic rod, the rotating rod is rotatably arranged at the bottom of the connecting plate, the fixed block is arranged at the lower end of the rotating rod, and the movable block is arranged on the U-shaped frame and hinged to the fixed block.

[0013] It can be seen that when the fixture driving the crankshaft is worn, the crankshaft axis will shift after installation. When the fixture drives the crankshaft to rotate after installation, the crankshaft axis will swing in the XOY, XOZ, and YOZ planes, affecting the fit of the positioning roller and the crankshaft connecting rod journal surface, and thus affecting the accuracy of the measurement results. Therefore, this solution is adopted. The rotational connection between the rotating rod and the connecting plate, as well as the hinged connection between the fixed block and the movable block, can provide the movable block with horizontal and vertical rotational freedom. During the swinging of the crankshaft axis, the pressure of the elastic telescopic rod can make the pressure roller fit the surface of the crankshaft connecting rod journal, thereby ensuring the accuracy of the laser measuring instrument's measurement results.

[0014] Preferably, the positioning roller includes a pressure roller and an annular plate, the pressure roller is a magnetic roller and is rotatably arranged inside the U-shaped plate, the annular plate is a non-magnetic steel plate, the annular plate is sleeved on the surface of the pressure roller and multiple annular plates are arranged in an array along the axis of the pressure roller.

[0015] It can be seen that before measuring the diameter of the crankshaft's connecting rod journal surface using laser measurement, it is necessary to ensure the cleanliness of the measured object's surface to prevent impurities adhering to the crankshaft's connecting rod journal surface from affecting the measurement results. However, under the conditions of factory batch production, it is impossible to effectively guarantee that the connecting rod journal surface of each crankshaft is free of impurities, and thus the measurement results cannot be guaranteed. Therefore, this solution is adopted. The pressure roller is provided, and under the influence of the pressure roller's magnetic force, it can absorb iron impurities adhering to the surface of the crankshaft's connecting rod journal, preventing the measurement results from being affected by impurities during the laser measuring instrument measurement process, thereby ensuring the accuracy of the measurement results.

[0016] Preferably, a torsion spring is sleeved on the rotating rod, and two ends of the torsion spring are respectively connected to the connecting plate and the fixing block.

[0017] By adopting the above solution, when the axis of the crankshaft deviates in the horizontal plane, the rotating rod can provide the U-shaped frame with freedom of rotation in the horizontal direction. Under the action of the torsion spring, after the measurement work is completed and the annular plate is separated from the connecting rod journal of the crankshaft, the U-shaped frame can automatically reset and keep the angle of the U-shaped frame fixed under the limiting action of the torsion spring. Therefore, when the clamp is not worn, each downward movement of the U-shaped frame can ensure that each annular plate on the pressure roller fits the surface of the connecting rod journal of the crankshaft.

[0018] Preferably, the thickness of the annular plate decreases from the inner circle to the outer circle.

[0019] By adopting the above scheme, the iron impurities attached to the surface of the connecting rod journal of the crankshaft can be guided to the surface of the pressing roller under the action of the inclined surfaces on both sides of the annular plate during the process of being adsorbed by the pressing roller, thereby avoiding the iron impurities remaining in the center position of the outer edge of the annular plate, which will cause the annular plate and the surface of the connecting rod journal of the crankshaft to be unable to fit stably, thereby further ensuring the measurement results.

[0020] Preferably, there are two pressing rollers, the distance between the axes of the two pressing rollers is smaller than the diameter of the connecting rod journal of the crankshaft, and the laser measuring instrument is arranged directly above the two pressing rollers.

[0021] By adopting the above solution, during the rotation of the crankshaft, the annular plates on the surfaces of the two pressure rollers can fit onto the surface of the connecting rod journal of the crankshaft, so that the extension line of the output end of the laser measuring instrument can always intersect with the axis of the connecting rod journal of the crankshaft, thereby ensuring the accuracy of the measurement results.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. By setting a synchronous component, a follower component, a laser measuring instrument and two pressure rollers arranged under the follower component, and the distance between the axes of the two pressure rollers is smaller than the diameter of the connecting rod journal, the synchronous component can be used to pull the corresponding two sets of pressure rollers to move synchronously in the horizontal direction to just above the corresponding connecting rod journal before measurement, which effectively simplifies the measurement operation during factory batch production operations. In the measurement process, the clamp is used to clamp the two ends of the crankshaft and drive the crankshaft to rotate. When the measured connecting rod journal rotates slowly and uniformly around the axis of the main journal of the crankshaft, the elastic force of the elastic telescopic rod in the follower component can be used to press the two pressure rollers. Rollers ensure that the two pressure rollers fit on the surface of the corresponding connecting rod journal of the crankshaft to be measured, thereby ensuring that the measurement results of the laser measuring instrument are accurate. When the fixture is worn, the connecting parts in the follower assembly can be used to synchronously provide the two pressure rollers with the freedom of rotation in the horizontal and vertical directions. This ensures that when the fixture wear is small (that is, the axial offset of the main journal of the crankshaft is small), the two pressure rollers can still be stably fitted with the surface of the corresponding connecting rod journal, thereby avoiding the situation where the pressure rollers jump and separate from the connecting rod journal to be measured during the measurement process, effectively ensuring the accuracy of the measurement results, thereby ensuring the subsequent performance of the engine.

[0024] 2. By setting up a synchronization component, when the pressure rollers at both ends of the synchronization component are in contact with the surface of the connecting rod journal to be measured, whether there is relative movement between the two U-shaped rods in the synchronization component, that is, whether the pressure value of the baffle on the pressure sensor caused by the elastic force of the spring changes, it can be judged whether the axes of the two connecting rod journals to be measured at the end position or the middle position coincide with each other, that is, before measuring the diameter of the connecting rod journal, it can be judged whether the crankshaft is unqualified due to other factors, and because the connecting part can provide the pressure roller with the freedom of rotation in the horizontal and vertical directions, it will not affect the measurement of the diameter of the connecting rod journal, which can further ensure the quality of the crankshaft and thus ensure the performance of the subsequent engine.

[0025] 3. Through the provided connecting parts, since the crankshaft is in a rotating state during the measurement process, when the wear of the fixture is large and causes a large offset of the axis of the crankshaft's main journal, as the crankshaft rotates, the two ends of the axis of the crankshaft's main journal will swing with different amplitudes. Therefore, after the measurement operation is completed, the measurement results of the four laser measuring instruments can objectively reflect the wear of the fixture, thereby reminding the staff to maintain or replace the fixture to ensure the normal progress of subsequent measurement operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0027] Figure 2 For the present invention Figure 1 Schematic diagram of the connection structure between the middle mounting plate, one of the follower components and the positioning roller;

[0028] Figure 3 For the present invention Figure 1 Schematic diagram of the local connection structure of the follower component and the synchronous component;

[0029] Figure 4 For the present invention Figure 3 An enlarged view of the local part A in the middle;

[0030] Figure 5 For the present invention Figure 2 Schematic diagram of the connection structure between the elastic telescopic rod, the connecting piece and the U-shaped frame;

[0031] Figure 6 For the present invention Figure 5 An enlarged view of the local B portion;

[0032] Figure 7 For the present invention Figure 5 Schematic diagram of the structure of the intermediate pressure roller;

[0033] Figure 8 This is a diagram showing a state in which two connecting rod journals at the upper end of the crankshaft of the present invention are located at the bottom;

[0034] Figure 9 This is a diagram showing a state in which the axes of the four connecting rod journals on the crankshaft are located in the same horizontal plane during the measurement process of the present invention;

[0035] Figure 10 This is another state diagram in which the axes of the four connecting rod journals on the crankshaft are located in the same horizontal plane during the measurement process of the present invention.

[0036] In the figure: 1. Mounting plate; 11. Strip mouth; 2. Crankshaft; 3. Follow-up assembly; 31. U-shaped rod 1; 32. Slider; 33. Elastic telescopic rod; 34. Connecting piece; 341. Connecting plate; 342. Rotating rod; 343. Fixed block; 344. Movable block; 345. Torsion spring; 35. U-shaped frame; 36. Electric guide rail; 37. U-shaped plate; 4. Positioning roller; 41. Pressure roller; 42. Ring plate; 5. Laser measuring instrument; 6. Synchronizing assembly; 61. Fixed frame; 62. U-shaped rod 2; 63. Connecting rod; 64. Spring; 65. Baffle; 66. Pressure sensor. DETAILED DESCRIPTION

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0038] See also Figures 1 to 10 The present invention provides an online diameter measuring device for large free forgings, and the technical solution is as follows:

[0039] For details, please refer to Figure 1 、 Figure 2 、 Figure 8 、 Figure 9 and Figure 10An online diameter measuring device for large free forgings includes a mounting plate 1 for use with a crankshaft 2, a follower assembly 3, a positioning roller 4, a laser measuring instrument 5, and a synchronization assembly 6. The follower assembly 3 is arranged on the mounting plate 1 and is provided with two groups, each group is provided with two, the positioning roller 4 is arranged on the follower assembly 3, the laser measuring instrument 5 is arranged on the follower assembly 3, and the follower assembly 3 includes a U-shaped rod 31, a slider 32, an elastic telescopic rod 33, a connecting piece 34, a U-shaped frame 35, The electric guide rail 36 and the U-shaped plate 37, the U-shaped rod 31 is arranged on the mounting plate 1 and the horizontal section is arranged perpendicular to the axis of the crankshaft 2, the slider 32 is arranged on the U-shaped rod 31, the elastic telescopic rod 33 is arranged on the slider 32, the connecting piece 34 is arranged on the elastic telescopic rod 33, the U-shaped frame 35 is arranged on the elastic telescopic rod 33, the electric guide rail 36 and the U-shaped plate 37 are both arranged on the U-shaped frame 35, the laser measuring instrument 5 is arranged on the electric guide rail 36, and the positioning roller 4 is arranged inside the U-shaped plate 37.

[0040] Under the above setting conditions, during measurement, the two ends of the crankshaft 2 are clamped and fixed by a clamp, and the mounting plate 1 is driven downward by an external electric push rod. During the downward movement of the mounting plate 1, the U-shaped rod 31 is driven downward. Since the slider 32 is set on the U-shaped rod 31, it will follow the U-shaped rod 31 to move downward. When the slider 32 moves downward, the elastic telescopic rod 33 is driven downward. The elastic telescopic rod 33 is connected to the U-shaped frame 35 through the connecting piece 34, and the U-shaped frame 35 is driven downward. When the U-shaped frame 35 moves downward, it drives the U-shaped plate 37 to move downward, so that the positioning roller 4 set inside the U-shaped plate 37 fits with the surface of the corresponding connecting rod journal on the crankshaft 2. At this time, the mounting plate 1 continues to move downward under the drive of the external electric push rod, so that each elastic telescopic rod 33 is in a retracted state; when the clamp drives the crankshaft 2 to rotate, the slider 32 is movably connected to the horizontal section of the U-shaped rod 31, and the horizontal section of the U-shaped rod 31 is perpendicular to the axis of the crankshaft 2. Under the elastic force of the elastic telescopic rod 33, the positioning roller 4 always keeps in contact with the surface of the connecting rod journal of the crankshaft 2, and the rigidity of the U-shaped frame 35 can meet the requirement that it will not deform during the measurement process, thereby ensuring that the distance between the laser measuring instrument 5 and the connecting rod journal of the crankshaft 2 is fixed, thereby ensuring the accuracy of the measurement results.

[0041] As an embodiment of the present invention, refer to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 8 、 Figure 9 and Figure 10There are two synchronization components 6, and the two ends of each synchronization component 6 are respectively connected to the corresponding follower component 3. The synchronization component 6 includes two fixing frames 61, two U-shaped rods 62, a connecting rod 63, a spring 64, a baffle 65 and a pressure sensor 66. A strip opening 11 is opened on the mounting plate 1. The fixing frame 61 passes through the strip opening 11 and is connected to the slider 32. The open end of the U-shaped rod 62 is hinged to the fixing frame 61. The connecting rod 63 passes through the closed end of one of the U-shaped rods 62 and is connected to the closed end of the other U-shaped rod 62. The baffle 65 is sleeved on the connecting rod 63 and is located inside the corresponding U-shaped rod 62. The spring 64 is arranged between the connecting rod 63 and the baffle 65 and is sleeved on the connecting rod 63. The pressure sensor 66 is arranged on the inner wall of the closed end of the corresponding U-shaped rod 62.

[0042] Under the above-mentioned setting conditions, since the four connecting rod journals on the crankshaft 2 are coaxial in pairs, one of the fixing frames 61 is pulled before measurement, and the fixing frame 61 can drive the other fixing frame 61 to move synchronously under the connection action of the two U-shaped rods 2 62 and the connecting rod 63, and the two fixing frames 61 can respectively drive the corresponding sliders 32 to move along the horizontal section of the corresponding U-shaped rod 1 31 during the movement. Since two positioning rollers 4 are connected to the bottom of each slider 32, the effect of simultaneously adjusting the two groups of positioning rollers 4 at the end positions or the two groups of positioning rollers 4 at the middle positions is achieved, which effectively simplifies the preparation work before measurement and ensures measurement efficiency. In addition, since the axis of each connecting rod journal is the same as the axis of the main journal of the crankshaft 2, errors during installation will lead to This causes the axes of the two connecting rod journals at the end or middle position to be non-collinear. When this happens, since the two U-shaped rods 62 are hinged to the corresponding fixing frames 61 respectively, after the two positioning rollers 4 under each fixing frame 61 fit the surface of the connecting rod journal of the corresponding crankshaft 2, the hinges of the two U-shaped rods 62 and the corresponding fixing frames 61 will rotate, thereby causing the distance between the two U-shaped rods 62 to change, resulting in the baffle 65 approaching and squeezing the pressure sensor 66 under the action of the connecting rod 63 and the spring 64. The value change of the pressure sensor 66 can be used to determine whether the two connecting rod journals at the end or middle position on the crankshaft 2 are collinear, thereby avoiding affecting the use function of the crankshaft 2 when the measured diameter of the connecting rod journal of the crankshaft 2 meets the product requirements.

[0043] As an embodiment of the present invention, refer to Figure 5 、 Figure 6 、 Figure 8 、 Figure 9 and Figure 10The connecting member 34 includes a connecting plate 341, a rotating rod 342, a fixed block 343 and a movable block 344. The connecting plate 341 is arranged at the lower end of the elastic telescopic rod 33, the rotating rod 342 is rotatably arranged at the bottom of the connecting plate 341, the fixed block 343 is arranged at the lower end of the rotating rod 342, and the movable block 344 is arranged on the U-shaped frame 35 and hinged to the fixed block 343; a torsion spring 345 is sleeved on the rotating rod 342, and the two ends of the torsion spring 345 are respectively connected to the connecting plate 341 and the fixed block 343.

[0044] Under the above-mentioned setting conditions, when the clamps holding the two ends of the crankshaft 2 are worn after a long period of measurement work, the two ends of the crankshaft 2 will have the axis of the main journal offset after being clamped, causing the two ends of the crankshaft 2 to swing when rotating during the measurement process. If the wear of the clamp is small, since the rotating rod 342 can provide the freedom of rotation in the horizontal direction, the hinge of the fixed block 343 and the movable block 344 can provide the freedom of rotation in the vertical direction, so during the slow rotation of the crankshaft 2 during measurement, the elastic force of the elastic telescopic rod 33 can be used to squeeze the positioning roller 4 and the surface of the connecting rod journal of the crankshaft 2 to maintain a stable fit, that is, the distance between the laser measuring instrument 5 and the connecting rod journal of the crankshaft 2 remains fixed, thereby ensuring the accuracy of the measurement results; if the wear of the clamp is large (the staff cannot perceive it at this time), the crankshaft 2 will be in a stable state. During the rotation of shaft 2, there will be a large amount of jumping at both ends. When each positioning roller 4 can keep in contact with the surface of the connecting rod journal of crankshaft 2 during measurement, the measurement result is accurate. When the positioning roller 4 jumps during measurement, that is, the positioning roller 4 cannot keep in contact with the surface of the connecting rod journal of crankshaft 2, the measurement results of each connecting rod journal will have a large deviation when the swing amplitude at both ends of crankshaft 2 is different. At this time, the wear of the fixture can be concluded through the measurement results, thereby reminding the staff to maintain or replace the fixture to avoid affecting the subsequent measurement results.

[0045] As an embodiment of the present invention, refer to Figure 1 、 Figure 5 and Figure 7 The positioning roller 4 includes a pressure roller 41 and an annular plate 42. The pressure roller 41 is a magnetic roller and is rotatably arranged inside the U-shaped plate 37. The annular plate 42 is a non-magnetic steel plate. The annular plate 42 is sleeved on the surface of the pressure roller 41 and multiple annular plates 42 are arranged in an array along the axis of the pressure roller 41; the thickness of the annular plate 42 is arranged to decrease from the inner ring to the outer ring; there are two pressure rollers 41, and the distance between the axes of the two pressure rollers 41 is less than the diameter of the connecting rod journal of the crankshaft 2. The laser measuring instrument 5 is arranged directly above the two pressure rollers 41.

[0046] Under the above-mentioned setting conditions, when the crankshaft 2 rotates during the measurement process, the iron filings impurities attached to the surface of the crankshaft 2 but not yet in contact with the annular plate 42 can be adsorbed under the magnetic force of the pressure roller 41, and the iron filings impurities can be guided to the surface of the pressure roller 41 under the guidance of the inclined surface of the annular plate 42, thereby avoiding the situation where the pressure roller 41 jumps due to impurities during the rotation of the crankshaft 2, and can further ensure the accuracy of the measurement results.

[0047] Working principle:

[0048] Before measurement, the two ends of the crankshaft 2 are clamped by a clamp, and one of the fixing brackets 61 at the end position or the middle position is pulled down respectively. Since each fixing bracket 61 is hinged with a U-shaped rod 2 62, and the two U-shaped rods 2 62 at the same height are connected by a connecting rod 63, when one fixing bracket 61 is pulled, the other U-shaped rod 2 62 can be driven to move under the action of the connecting rod 63, and in the process of the movement of the two U-shaped rods 2 62, the stiffness of the spring 64 provided on the connecting rod 63 can be used to overcome the rotation of the hinge between the U-shaped rod 2 62 and the corresponding fixing bracket 61, so that each fixing bracket 61 is moved down. The two pressure rollers 41 on the right side can be located on both sides of the corresponding connecting rod journal on the crankshaft 2. At this time, the mounting plate 1 is driven downward by the external electric push rod. During the downward movement of the mounting plate 1, the elastic telescopic rod 33 is driven downward by the U-shaped rod 1 31 and the slider 32 until the two pressure rollers 41 under each fixing frame 61 are in contact with the surface of the corresponding connecting rod journal on the crankshaft 2. At this time, each elastic telescopic rod 33 is in a compressed state, and the extension line of the output end of each laser measuring instrument 5 intersects with the axis of the corresponding connecting rod journal on the crankshaft 2. The crankshaft 2 is driven to rotate by the fixture, and the laser measuring instrument 5 is driven to move back and forth by the electric push rod to realize dynamic measurement.

[0049] If the fixture is not worn: at this time, each pressure roller 41 is in contact with the surface of the corresponding connecting rod journal on the crankshaft 2. During the process of the connecting rod journal on the crankshaft 2 rotating around the axis of the main journal of the crankshaft 2, the elastic force of the elastic telescopic rod 33 squeezes the connecting piece 34, and the U-shaped frame 35 is squeezed through the conduction effect of the connecting piece 34. The rigidity of the U-shaped frame 35 can ensure that the two pressure rollers 41 below it are in contact with the surface of the corresponding connecting rod journal and are located on both sides of the axis of the connecting rod journal, thereby ensuring the accuracy of the measurement results of the laser measuring instrument 5. If the measurement results of the laser measuring instrument 5 do not change, it means that the quality of the connecting rod journal is qualified, otherwise it is unqualified.

[0050] If the fixture is worn but the amount of wear is small, that is, the offset of the axis of the main journal of the crankshaft 2 is small after being clamped: in this case, during the measurement process, since the crankshaft 2 rotates slowly and uniformly, the elastic force of the elastic telescopic rod 33 can still ensure that each pressure roller 41 is stably fitted with the corresponding connecting rod journal surface, that is, the accuracy of the measurement result can still be guaranteed while meeting the requirements of factory batch production operations;

[0051] If the fixture is worn but the amount of wear is large, that is, the axis of the main journal of the crankshaft 2 is greatly offset after being clamped: at this time, during the measurement process, the swing amplitude of the two ends of the crankshaft 2 is large, and the swing amplitude of the end position of the crankshaft 2 is larger than that of the middle position. When the positioning roller 4 jumps, it will cause a large deviation in the measurement result of the laser measuring instrument 5. The measurement result of the end position deviates greatly from the measurement result of the middle position, which can objectively reflect the wear of the fixture rather than the unqualified quality of the crankshaft 2, thereby reminding the staff to maintain or replace the fixture to ensure the normal progress of subsequent measurement operations;

[0052] If the axes of the two connecting rod journals at the end or middle position on the crankshaft 2 do not coincide (taking the two connecting rod journals at the end position on the crankshaft 2 as an example), the connection between the two fixing frames 61 and the corresponding U-shaped rods 62 will deflect due to the hinge effect, that is, the distance between the two U-shaped rods 62 will change. Since the connecting rod 63 is fixedly connected to one of the U-shaped rods 62 and is sleeved with the other U-shaped rod 62, the free end of the connecting rod 63 will be close to the closed end of the U-shaped rod 62 sleeved therewith. A baffle 65 is sleeved, and a spring 64 is arranged between the baffle 65 and the free end of the connecting rod 63. When the free end of the connecting rod 63 is close to the closed end of the U-shaped rod 2 62 sleeved therewith, the baffle 65 will be squeezed by the spring 64, and finally the baffle 65 will squeeze the pressure sensor 66. The value change of the pressure sensor 66 can be used to determine whether the axes of the two connecting rod journals at the end positions coincide. Under the premise of simplifying the preparation work before measurement, it is not necessary to measure the diameter of the connecting rod journal of the crankshaft 2 to determine whether the crankshaft 2 is qualified.

[0053] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An online diameter measuring device for large free forgings, comprising a mounting plate (1) for use with a crankshaft (2), characterized in that: It also includes a follower assembly (3), a positioning roller (4), a laser measuring instrument (5) and a synchronization assembly (6), wherein the follower assembly (3) is arranged on the mounting plate (1) and is provided with two groups, each group is provided with two, the positioning roller (4) is arranged on the follower assembly (3), the laser measuring instrument (5) is arranged on the follower assembly (3), and the synchronization assembly (6) is provided with two, and both ends of each synchronization assembly (6) are respectively connected to the corresponding follower assembly (3), and before measurement, the synchronization assembly (6) is pulled to move in a direction perpendicular to the axis of the main journal of the crankshaft (2), and when the synchronization assembly (6) moves, the corresponding two positioning rollers (4) are driven to both sides of the axis of the connecting rod journal of the crankshaft (2) through the follower assembly (3), and when measuring, the mounting plate (1) moves down and drives the two positioning rollers (4) to move down to fit with the surface of the connecting rod journal of the crankshaft (2) through the follower assembly (3), and when the crankshaft (2) rotates, the positioning roller (4) keeps fitting with the connecting rod journal of the crankshaft (2); The follower assembly (3) includes a U-shaped rod (31), a slider (32), an elastic telescopic rod (33), a connector (34), a U-shaped frame (35), an electric guide rail (36) and a U-shaped plate (37), wherein the U-shaped rod (31) is arranged on the mounting plate (1) and the horizontal section is arranged perpendicular to the axis of the crankshaft (2), the slider (32) is arranged on the U-shaped rod (31), the elastic telescopic rod (33) is arranged on the slider (32), the connector (34) is arranged on the elastic telescopic rod (33), the U-shaped frame (35) is arranged on the elastic telescopic rod (33), the electric guide rail (36) and the U-shaped plate (37) are both arranged on the U-shaped frame (35), the laser measuring instrument (5) is arranged on the electric guide rail (36), and the positioning roller (4) is arranged inside the U-shaped plate (37); The synchronization component (6) includes two fixing frames (61), two U-shaped rods (62), a connecting rod (63), a spring (64), a baffle (65) and a pressure sensor (66). The mounting plate (1) is provided with a strip opening (11). The fixing frame (61) passes through the strip opening (11) and is connected to the slider (32). The open end of the U-shaped rod (62) is hinged to the fixing frame (61). The connecting rod (63) passes through the closed end of one of the U-shaped rods (62) and is connected to the closed end of the other U-shaped rod (62). The baffle (65) is sleeved on the connecting rod (63) and is located inside the corresponding U-shaped rod (62). The spring (64) is arranged between the connecting rod (63) and the baffle (65) and sleeved with the connecting rod (63). The pressure sensor (66) is arranged on the inner wall of the closed end of the corresponding U-shaped rod (62).

2. The online diameter measuring device for large free forgings according to claim 1, characterized in that: The connecting member (34) comprises a connecting plate (341), a rotating rod (342), a fixed block (343) and a movable block (344); the connecting plate (341) is arranged at the lower end of the elastic telescopic rod (33); the rotating rod (342) is rotatably arranged at the bottom of the connecting plate (341); the fixed block (343) is arranged at the lower end of the rotating rod (342); and the movable block (344) is arranged on the U-shaped frame (35) and is hinged to the fixed block (343).

3. The online diameter measuring device for large free forgings according to claim 1, characterized in that: The positioning roller (4) comprises a pressure roller (41) and an annular plate (42), wherein the pressure roller (41) is a magnetic roller and is rotatably arranged inside the U-shaped plate (37), and the annular plate (42) is a non-magnetic steel plate. The annular plates (42) are sleeved on the surface of the pressure roller (41) and are arranged in an array along the axis of the pressure roller (41).

4. The online diameter measuring device for large free forgings according to claim 2, characterized in that: A torsion spring (345) is sleeved on the rotating rod (342), and two ends of the torsion spring (345) are respectively connected to the connecting plate (341) and the fixing block (343).

5. The online diameter measuring device for large free forgings according to claim 3, characterized in that: The thickness of the annular plate (42) is set to decrease from the inner circle to the outer circle.

6. The online diameter measuring device for large free forgings according to claim 3, characterized in that: Two pressing rollers (41) are provided, and the distance between the axes of the two pressing rollers (41) is smaller than the diameter of the connecting rod journal of the crankshaft (2). The laser measuring instrument (5) is provided directly above the two pressing rollers (41).

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