Diameter on-line measuring device for large free forgings

Abstract

The invention relates to the technical field of crankshaft measurement, in particular to a diameter online measuring device for a large free forge piece, which comprises a mounting plate used for being matched with a crankshaft for use, and further comprises two groups of follow-up assemblies, a positioning roller, a laser measuring instrument and a synchronization assembly, the follow-up assemblies are arranged on the mounting plate, each group comprises two follow-up assemblies, and the positioning roller is arranged on the mounting plate; the positioning roller is arranged on the follow-up assemblies, the laser measuring instrument is arranged on the follow-up assemblies, the number of the synchronization assemblies is two, the two ends of each synchronization assembly are connected with the corresponding follow-up assemblies respectively, and the synchronization assemblies are pulled to move in the direction perpendicular to the axis of a main journal of a crankshaft before measurement. Through the follow-up assembly, the synchronization assembly and the positioning roller, the positioning roller can be stably attached to the surface of the rod journal to be measured when the axis of the crankshaft does not deviate or the deviation amount is small, and therefore the accuracy of the measurement result is guaranteed.

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] Free forgings are a type of metal forgings produced by free forging. In the manufacture of automotive parts, free forging is often used to produce gears and shaft parts. The crankshaft is the most important component in a car engine. During operation, it converts the pressure from each piston assembly into torque, thereby driving the car to run normally.

[0003] During the manufacturing process of the crankshaft, the diameter of the connecting rod journal needs to be measured to avoid the large deviation in the diameter accuracy of the connecting rod journal, which may cause serious wear of the connecting rod and piston during operation, thereby affecting the performance of the engine. The traditional measurement method is to use an outside micrometer and measure the diameter of the connecting rod journal by manual sampling (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). Since the crankshafts in the production workshop are mass-produced, the measurement efficiency is limited, and the measurement results are largely affected by the work experience of the staff, and the accuracy of the measurement results cannot be effectively guaranteed, which will cause the crankshaft to affect the performance of the engine in subsequent use. In view of the above problems, there are good solutions in the prior art, such as a four-axis linkage tracking crankshaft measurement method with patent number: CN105333828B, which adopts a four-axis tracking linkage motion structure, is 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, which improves the measurement efficiency while ensuring the measurement accuracy, thereby ensuring the performance of the engine in subsequent use. However, there are still the following defects: since the two ends of the crankshaft need to be clamped by the fixture during the measurement process and then driven to rotate around the main journal of the crankshaft, when the factory performs mass production operations, the fixture needs to be frequently used to clamp the two ends of the crankshaft to be measured. The jaws in the fixture used for a long time will rub against different crankshaft surfaces during each installation of the crankshaft and cause wear, which will cause the two ends of the crankshaft to deviate from the axis after being clamped (taking the three-jaw chuck as an example, the front and back wear of the jaws are uneven after long-term use, which will cause the jaws to be flared, resulting in the three-jaw chuck to deviate from the center of the lathe spindle after clamping the workpiece). During the measurement process, since the fixture drives the crankshaft to rotate continuously, when the main journal axis of the crankshaft is offset, the entire crankshaft will swing simultaneously in the XOY, XOZ and YOZ planes, and the swing amplitude of the end position is greater than that of the middle position, resulting in the inability of the follow-up probe to stably contact the surface of the connecting rod journal to be measured on the crankshaft, which will also affect the measurement results and still cannot effectively guarantee the performance of the engine in 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 purpose of the present invention is to provide an online diameter measuring device for large free forgings, which solves the problem that when the factory is mass-produced and frequently uses the fixture to assist the measurement operation, if the fixture is worn, the main axis of the crankshaft after clamping will be offset, thereby affecting the accuracy of the measurement result, and thus the performance of the engine cannot be effectively guaranteed when the crankshaft is used in the subsequent use. Through the provided follower assembly, synchronization assembly and positioning roller, two sets of positioning rollers can be pulled to the top of the connecting rod journal to be measured before measurement, which effectively simplifies the measurement work during the factory's mass production operation. When the axis of the main journal of the crankshaft is offset due to the wear of the fixture, the follower assembly can be used to provide the roller with the horizontal and vertical rotational freedom, so that when the axis offset of the main journal of the crankshaft is small or no offset occurs, the roller can still be ensured to be stably fitted with the surface of the corresponding connecting rod journal, thereby ensuring the accuracy of the measurement result, and then ensuring the performance of the engine in the subsequent use. And it can judge the influence of other factors on the quality of the crankshaft under the action of the pressure sensor in the follower assembly, further ensuring the performance of the engine.

[0006] To achieve the above object, the present invention provides the following technical solutions: An online diameter measuring device for large free forgings comprises 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, and before measurement, the synchronization assembly is pulled to move in a direction perpendicular to the axis of the main journal of the crankshaft, and 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, and when measuring, the mounting plate moves down and drives the two positioning rollers to move down to fit with the surface of the connecting rod journal of the crankshaft through the follower assembly, and the positioning roller keeps fitting with the connecting rod journal of the crankshaft when the crankshaft rotates.

[0007] 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, the positioning roller is arranged inside the U-shaped plate, and when the axis of the crankshaft is offset, the positioning roller is kept in contact with the connecting rod journal of the crankshaft through the connecting piece.

[0008] 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 by frequent use of a fixture to ensure that the crankshaft can rotate on its own main journal during the measurement process. Frequent use will cause wear of the fixture, causing the axis of the crankshaft to shift after the fixture clamps the crankshaft, which will cause the distance between the laser measuring instrument and the connecting rod journal of the crankshaft to change dynamically during the measurement process 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 by the connecting piece to the pressure roller in the horizontal and vertical directions 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.

[0009] 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-shaped opening is opened on the mounting plate, the fixing frame passes through the strip-shaped 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.

[0010] It can be seen that there are many ways to judge the quality of the 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 detect separately. Considering that separate detection takes a long time during factory batch production, which affects work efficiency, this solution is adopted. Through the setting of 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, and when the axes of the two connecting rod journals at the end or middle position 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 of the crankshaft but unqualified in other aspects.

[0011] 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.

[0012] It can be seen that when the clamp driving the crankshaft to rotate is worn, the axis of the crankshaft will be offset after installation. When the clamp drives the crankshaft to rotate after the crankshaft is installed, the axis of the crankshaft will swing in the XOY, XOZ and YOZ planes, thereby affecting the fit between the positioning roller and the surface of the connecting rod journal of the crankshaft, and further affecting the accuracy of the measurement results. Therefore, this solution is adopted. Through the rotational connection between the rotating rod and the connecting plate and the hinged connection between the fixed block and the movable block, the movable block can be provided with horizontal and vertical rotational freedom. During the swinging process of the crankshaft axis, the pressure of the elastic telescopic rod can make the pressure roller fit the surface of the connecting rod journal of the crankshaft, thereby ensuring the accuracy of the measurement results of the laser measuring instrument.

[0013] 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.

[0014] It can be seen that before measuring the diameter of the surface of the crankshaft connecting rod journal by laser measurement, it is necessary to ensure the cleanliness of the surface of the object being measured to avoid the impurities attached to the surface of the crankshaft connecting rod journal affecting the measurement results. However, under the conditions of factory batch production, it is impossible to effectively ensure that there are no impurities attached to the surface of the connecting rod journal of each crankshaft, and thus the measurement results cannot be guaranteed. Therefore, this solution is adopted. Through the setting of the pressure roller, under the magnetic force of the pressure roller, the iron impurities attached to the surface of the crankshaft connecting rod journal can be adsorbed, avoiding the laser measuring instrument causing the measurement results to be affected by impurities during the measurement process, thereby ensuring the accuracy of the measurement results.

[0015] 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.

[0016] By adopting the above scheme, when the axis of the crankshaft is offset 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.

[0017] Preferably, the thickness of the annular plate decreases from the inner circle to the outer circle.

[0018] 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 preventing the iron impurities from remaining in the center position of the outer edge of the annular plate, causing 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.

[0019] Preferably, two pressing rollers are provided, 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.

[0020] By adopting the above scheme, 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.

[0021] Compared with the prior art, the present invention has the following beneficial effects: 1. By setting a synchronous component, a follower component, a laser measuring instrument and two rollers arranged under the follower component, and the distance between the axes of the two rollers is smaller than the diameter of the connecting rod journal, the synchronous component can be used to pull the corresponding two groups of 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, and during the measurement process, the two ends of the crankshaft are clamped by a fixture and the crankshaft is driven to rotate. In the process of the measured connecting rod journal rotating 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 rollers. Rollers ensure that the two pressure rollers fit on the surface of the corresponding connecting rod journal of the crankshaft to be measured, so as to ensure 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. When the fixture wears little (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 performance of the subsequent engine.

[0022] 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, it is possible to determine whether the axes of the two connecting rod journals to be measured at the end positions or the middle positions coincide by utilizing whether there is relative movement between the two U-shaped rods in the synchronization component, that is, whether the pressure value caused by the baffle on the pressure sensor under the elastic force of the spring changes. In other words, before measuring the diameter of the connecting rod journal, it is possible to determine whether the crankshaft is unqualified due to other factors. Moreover, since the connecting piece 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.

[0023] 3. Through the setting of the 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

[0024] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 For the present invention Figure 1 A schematic diagram of the connection structure between the middle mounting plate and one of the follower components and the positioning roller; Figure 3 For the present invention Figure 1 Schematic diagram of the local connection structure of the follower component and the synchronous component; Figure 4 For the present invention Figure 3 An enlarged view of the local A in the middle; Figure 5 For the present invention Figure 2 Schematic diagram of the connection structure between the middle elastic telescopic rod, the connecting piece and the U-shaped frame; Figure 6 For the present invention Figure 5 An enlarged view of the local B portion; Figure 7 For the present invention Figure 5 Schematic diagram of the structure of the middle pressure roller; Figure 8 A state diagram showing that two connecting rod journals at the upper end of the crankshaft of the present invention are located at the bottom; Fig. 9 This is a state diagram in which the axes of four connecting rod journals on the crankshaft are located in the same horizontal plane during the measurement process of the present invention; Fig.10This 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.

[0025] In the figure: 1. mounting plate; 11. strip mouth; 2. crankshaft; 3. follower assembly; 31. U-shaped rod one; 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. annular plate; 5. laser measuring instrument; 6. synchronization assembly; 61. fixed frame; 62. U-shaped rod two; 63. connecting rod; 64. spring; 65. baffle; 66. pressure sensor. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0027] 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: For details, please refer to Figure 1 , Figure 2 , Figure 8 , Fig. 9 and Fig.10 , an online diameter measuring device for large free forgings, including 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, 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.

[0028] 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 to move downward by an external electric push rod. During the downward movement of the mounting plate 1, the U-shaped rod 31 is driven to move downward. Since the slider 32 is set on the U-shaped rod 31, it will move downward with the U-shaped rod 31. When the slider 32 moves downward, the elastic telescopic rod 33 is driven to move downward. The elastic telescopic rod 33 drives the U-shaped frame 35 to move downward through the connection between the connecting piece 34 and the U-shaped frame 35. 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 fixture drives the crankshaft 2 to rotate, the slider 32 is movably connected with 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 be satisfied 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 result.

[0029] As an embodiment of the present invention, refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 8 , Fig. 9 and Fig.10 There are two synchronization components 6, and both 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.

[0030] 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 of the two U-shaped rods 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 can be achieved, which effectively simplifies the preparation work before measurement and ensures the 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 will occur during installation. This causes the axes of the two connecting rod journals at the end or middle position to be not collinear. When this happens, since the two U-shaped rods 62 are respectively hinged to the corresponding fixing frames 61, after the two positioning rollers 4 under each fixing frame 61 fit with the corresponding connecting rod journal surface of the 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, so that it can be concluded whether the two connecting rod journals at the end or middle position of 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.

[0031] As an embodiment of the present invention, refer to Figure 5 , Figure 6 , Figure 8 , Fig. 9 and Fig.10 The 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 with 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.

[0032] 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, 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 it rotates during the measurement. 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 is kept 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 rotated slowly, and the positioning roller 4 and the connecting rod journal of the crankshaft 2 will be kept in a stable fit, and the distance between the laser measuring instrument 5 and the connecting rod journal of the crankshaft 2 will be kept fixed, thereby ensuring the accuracy of the measurement results. During the rotation process, the two ends of the shaft 2 will experience large fluctuations. When each positioning roller 4 can keep in contact with the surface of the connecting rod journal of the 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 the crankshaft 2, the measurement result of each connecting rod journal will have a large deviation when the swing amplitude at the two ends of the 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.

[0033] 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 decreases 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.

[0034] 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.

[0035] Working principle: Before measurement, the two ends of the crankshaft 2 are clamped by a clamp, and one of the fixing frames 61 at the end position or the middle position is pulled down respectively. Since each fixing frame 61 is hinged with a U-shaped rod 62, and the two U-shaped rods 62 at the same height are connected by a connecting rod 63, when one fixing frame 61 is pulled, the other U-shaped rod 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 62, the stiffness of the spring 64 arranged on the connecting rod 63 can be used to overcome the rotation of the hinge between the U-shaped rod 62 and the corresponding fixing frame 61, so that each fixing frame 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 to move downward by an external electric push rod. During the downward movement of the mounting plate 1, the elastic telescopic rod 33 is driven to move 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 reciprocate by the electric push rod to realize dynamic measurement. 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. When the connecting rod journal on the crankshaft 2 rotates 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 squeezes the U-shaped frame 35 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 result of the laser measuring instrument 5. If the measurement result of the laser measuring instrument 5 does not change, it means that the quality of the connecting rod journal is qualified, otherwise it is unqualified. 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 after being clamped is small: at this time, during the measurement process, since the crankshaft 2 rotates slowly and uniformly, under the elastic force of the elastic telescopic rod 33, each pressing roller 41 can still be ensured to be stably fitted with the corresponding connecting rod journal surface, that is, the accuracy of the measurement result can still be guaranteed while ensuring the needs of factory batch production operations; If the fixture is worn but the amount of wear is large, that is, the offset of the axis of the main journal of the crankshaft 2 after being clamped is large: 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 greater 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, and the measurement result of the end position has a large deviation 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; If the axes of the two connecting rod journals at the end or the middle of the crankshaft 2 do not coincide (taking the two connecting rod journals at the end of 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 action, 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 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 62 sleeved therewith, the baffle 65 will be squeezed by the spring 64, and finally the baffle 65 will squeeze the pressure sensor 66. It can be judged whether the axes of the two connecting rod journals at the end positions coincide with each other through the value change of the pressure sensor 66. Under the premise of simplifying the preparation work before measurement, it is possible to judge whether the crankshaft 2 is qualified without measuring the diameter of the connecting rod journal of the crankshaft 2.

[0036] Although 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 the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present 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: The invention also comprises a follower assembly (3), a positioning roller (4), a laser measuring instrument (5) and a synchronous assembly (6). The follower assembly (3) is arranged on the mounting plate (1) and is provided with two groups, each group being provided with two members. The positioning roller (4) is arranged on the follower assembly (3). The laser measuring instrument (5) is arranged on the follower assembly (3). The synchronous assembly (6) is provided with two members. Both ends of each synchronous assembly (6) are respectively connected to the corresponding follower assembly (3). Before measurement, the synchronous assembly (6) is pulled to move in a direction perpendicular to the axis of the main journal of the crankshaft (2). When the synchronous assembly (6) moves, the corresponding two positioning rollers (4) are driven to the two sides of the axis of the connecting rod journal of the crankshaft (2) through the follower assembly (3). When measuring, the mounting plate (1) moves downward and drives the two positioning rollers (4) downward to fit the surface of the connecting rod journal of the crankshaft (2) through the follower assembly (3). When the crankshaft (2) rotates, the positioning rollers (4) remain in fit with the connecting rod journal of the crankshaft (2).

2. The online diameter measuring device for large free forgings according to claim 1 is characterized in that: The follower assembly (3) comprises a U-shaped rod (31), a slider (32), an elastic telescopic rod (33), a connecting piece (34), a U-shaped frame (35), an electric guide rail (36) and a 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). The positioning roller (4) is arranged inside the U-shaped plate (37).

3. The online diameter measuring device for large free forgings according to claim 2, characterized in that: The synchronization component (6) comprises 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).

4. The on-line diameter measuring device for large free forgings according to claim 3 is 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).

5. The on-line diameter measuring device for large free forgings according to claim 2, characterized in that: The positioning roller (4) comprises 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 plates (42) are sleeved on the surface of the pressure roller (41) and are arranged in a plurality in an array along the axis of the pressure roller (41).

6. The on-line diameter measuring device for large free forgings according to claim 4, 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).

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

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

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