Device and method for detecting roundness of connecting rod bushing fit

Abstract

The application provides a device and method for detecting the fitting degree of a connecting rod bushing, and belongs to the technical field of connecting rod bushings.The device comprises a computer, a roundness detector, a rack, a clamp base, a connecting rod big-end hole clamp and a rod clamp.The connecting rod big-end hole clamp limits the movement freedom degree of the connecting rod, and the rod clamp limits the rotation freedom degree of the connecting rod.The roundness detector is used for detecting the roundness data of the inner surface of the bushing and transmitting the roundness data to the computer for processing and analysis.The method does not need to damage the integrity of the connecting rod bushing, reduces economic loss, avoids the waste of resources in the detection process, can detect all products, improves the yield, avoids the error of manual judgment, improves the detection quality and detection efficiency, and improves the detection accuracy by detecting the roundness of the inner surface of the bushing.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of connecting rod bushing, and particularly relates to a device and method for detecting the fitting degree of a connecting rod bushing. BACKGROUND

[0002] A connecting rod is a key component of an engine, and the quality of the connecting rod directly affects the performance and service life of the engine. Therefore, the quality requirement for the connecting rod is also increasingly high. The fitting condition of the bushing and the connecting rod hole has an important influence on the use performance of the connecting rod, especially when there is a gap between the fitting of the connecting rod bushing and the connecting rod hole, which will seriously affect the use of the connecting rod.

[0003] The assembly of the bushing and the connecting rod hole is mostly in interference fit, and the pressure generated by the interference fit is connected together. The fitting between the bushing and the connecting rod is affected by multiple factors such as interference amount, manufacturing precision and assembly precision, and it is difficult to form a complete assembly surface of mutual contact and fit. If the fit rate of the assembly surface is low, the pressure generated by the interference fit is also relatively small, and mutual rotation or falling off will occur, and in serious cases, safety accidents will also occur.

[0004] The traditional method for detecting the fitting degree of the connecting rod bushing mainly adopts a destructive sampling inspection method. For example, the bushing with red powder on the outer wall is pressed into the small head hole of the connecting rod according to the normal assembly method, and then pressed out. The red powder on the fitting part will peel off, and then the trace on the outer circular surface of the bushing is transferred by transparent tape and pasted on the prepared grid paper, so that the fitting area can be judged.

[0005] This detection method has many deficiencies: the workpiece is damaged, resources are wasted; only sampling detection can be performed, and the reliability is low; manual operation, low detection efficiency.

[0006] Chinese Invention Patent CN110160424A discloses a detection tool and method for the fitting degree of a connecting rod bushing, including a cylindrical tool body with a plurality of arc-shaped detection windows arranged circumferentially; it can ensure a high fitting accuracy between the connecting rod bushing and the tool body and can accurately reflect the true shape of the connecting rod bushing in the small end of the connecting rod. The detection method includes: first pressing the connecting rod bushing into the tool body, placing the tool body with the pressed-in connecting rod bushing on the detection table, and calibrating the coordinate measuring machine or cylindricity measuring instrument; then using a detection probe to measure the roundness of the outer surface of the connecting rod bushing at different heights in the detection window, and fitting the measurement data to obtain the cylindricity of the outer surface of the connecting rod bushing; finally, determining the fitting degree according to the cylindricity, and if the cylindricity is within the specified range, it is qualified; it can quickly and accurately evaluate the fitting rate between the connecting rod bushing and the small end of the connecting rod and can avoid the situation of large data fluctuations caused by manual operation. However, since the connecting rod bushing is pressed into the tool body with a certain interference, the process of removing the connecting rod bushing is a destructive process, and the connecting rod bushing cannot be used after being removed, resulting in waste of resources; generally, this tool body is only used for equipment debugging and initial inspection of products, with low reliability; moreover, this method detects the cylindricity through the outer surface of the bushing at the detection window, but the outer surface at the detection window is not directly extruded, so the cylindricity measured here is not accurate. Summary of the Invention

[0007] In view of the problems existing in the above-mentioned prior art, the present invention provides a device and method for detecting the fitting degree of a connecting rod bushing by roundness. The technical problems to be solved by the present invention are how to improve the detection accuracy of the fitting degree of the connecting rod bushing and how to avoid the phenomenon of resource waste during the detection process.

[0008] To solve the above technical problems, the present invention provides a device for detecting the fitting degree of a connecting rod bushing by roundness, including a computer, a roundness measuring instrument, a frame, a fixture base, a connecting rod big-end hole fixture, and a rod body fixture;

[0009] The connecting rod is arranged on the upper surface of the fixture base, and the lower parts of the connecting rod big-end hole fixture and the rod body fixture are both connected to the fixture base;

[0010] The frame is connected to the lower surface of the fixture base, the roundness measuring instrument is connected to the upper part of the frame, and one end of the frame is electrically connected to the computer;

[0011] The connecting rod big-end hole fixture includes a positioning block and a positioning block track. The positioning block track is slidably connected to the lower part of the positioning block, and the positioning block can slide along the positioning block track to limit the movement freedom of the connecting rod;

[0012] The rod body fixture includes a clamping block and a clamping block track. The lower part of the clamping block is slidably connected to the clamping block track, and the clamping block can slide along the clamping block track to limit the rotation freedom of the connecting rod;

[0013] The roundness detector is used for detecting the roundness data of the inner surface of the bushing and transmitting the roundness data to a computer for processing and analysis.

[0014] Further, the big end hole clamp of the connecting rod comprises a plurality of positioning blocks and a plurality of positioning block tracks.

[0015] Further, the rod body clamp comprises a plurality of clamping blocks and a plurality of clamping block tracks.

[0016] Further, the roundness detector comprises a probe, the probe is arranged above the clamp base, and the upper end of the probe is connected with the rack.

[0017] Further, the positioning block track is connected to the upper surface of the clamp base.

[0018] Further, the clamping block track is connected to the upper surface of the clamp base.

[0019] Further, the rack is of an L-shaped structure.

[0020] Further, the device for detecting the roundness of the connecting rod bushing comprises the following steps:

[0021] Step S1: first, place the connecting rod assembled with the bushing on the clamp base;

[0022] Step S2: use the big end hole clamp of the connecting rod and the rod body clamp to position the connecting rod;

[0023] Step S3: use the roundness detector to collect the roundness data of the inner surface of the bushing;

[0024] Step S4: transmit the collected roundness data to the computer for processing and analysis to calculate the fit degree.

[0025] Further, the roundness detector collects the roundness data at different heights of the inner surface of the bushing in step S3.

[0026] Further, the processing and analysis of the roundness data by the computer in step S4 comprises the following steps:

[0027] Step H1: establish a three-dimensional bushing model A1 using the roundness data;

[0028] Step H2: establish a standard bushing model A2 based on a bushing that is not assembled and has not been deformed;

[0029] Step H3: select sampling points at the same positions on the three-dimensional bushing model A1 and the standard bushing model A2, and calculate the displacement δ of the corresponding points;

[0030] Step H4: compare the displacement δ with the threshold value λ of the deformation of the connecting rod, if the displacement δ is greater than the threshold value λ of the deformation of the connecting rod, it is determined that the sampling point is fit.

[0031] Step H5: calculate the ratio of the number of fitted sampling points to the total number of sampling points, that is, the fitting degree.

[0032] The present application proposes a device for detecting the fitting degree of a connecting rod bushing, which limits the translational movement of the connecting rod by setting a positioning block and a positioning block track; the device limits the rotation of the connecting rod by setting a clamp block and a clamp block track, and the clamp block moves along the clamp block track to the direction of approaching the connecting rod body to clamp the connecting rod, thereby improving the positioning accuracy of the connecting rod, facilitating the movement detection of the probe at the inner hole of the bushing, and improving the accuracy of the measured roundness data; the device can also adjust the movement distance of the positioning block and the clamp block according to connecting rods of different sizes to meet the fixture requirements in multiple scenarios.

[0033] The present application proposes a method for detecting the fitting degree of a connecting rod bushing, which does not need to damage the integrity of the connecting rod bushing, reduces economic losses, avoids resource waste during the detection process, and can detect all products to improve the yield rate; the method avoids the error of manual judgment, improves the detection quality and efficiency; the fitting degree is judged by detecting the roundness of the inner circular surface of the bushing, thereby improving the accuracy of the detection. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is the front view of the device for detecting the fitting degree of a connecting rod bushing of the present application.

[0035] Figure 2 is the top view of the device for detecting the fitting degree of a connecting rod bushing of the present application.

[0036] Figure 3 is the flowchart of the method for detecting the fitting degree of a connecting rod bushing of the present application.

[0037] 1, computer; 2, roundness detector; 3, rack; 4, clamp base; 5, connecting rod; 6, probe; 7, connecting rod big-end clamp; 8, rod body clamp; 9, bushing; 71, positioning block; 81, clamp block. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0039] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0040] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0041] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0042] To better understand the purpose, structure, and function of this invention, the apparatus and method for detecting the roundness of connecting rod bushing fitting of this invention will be described in further detail below with reference to the accompanying drawings.

[0043] Example 1:

[0044] like Figure 1 As shown, this embodiment provides a device for testing the roundness of connecting rod bushing fit, including a computer 1, a roundness tester 2, a frame 3, a fixture base 4, a connecting rod big end hole fixture 7, and a rod body fixture 8; the connecting rod 5 is disposed on the upper surface of the fixture base 4, and the lower parts of the connecting rod big end hole fixture 7 and the rod body fixture 8 are both connected to the fixture base 4.

[0045] The frame 3 is connected to the lower surface of the fixture base 4, the roundness detector 2 is connected to the upper part of the frame 3, and one end of the frame 3 is electrically connected to the computer 1.

[0046] The connecting rod big end hole clamp 7 includes a positioning block 71 and a positioning block track. The positioning block track is slidably connected to the lower part of the positioning block 71. The positioning block 71 can slide along the positioning block track to restrict the degree of freedom of movement of the connecting rod 5.

[0047] The rod clamp 8 includes a clamping block 81 and a clamping block track. The lower part of the clamping block 81 is slidably connected to the clamping block track. The clamping block 81 can slide along the clamping block track to restrict the rotational freedom of the connecting rod 5.

[0048] The roundness tester 2 detects the roundness data of the inner surface of the bushing and transmits it to the computer 1 for processing and analysis.

[0049] Embodiment 2:

[0050] As shown in Figure 1 and Figure 2 The embodiment provides a device for detecting the roundness of a connecting rod bushing, which comprises a computer 1, a roundness detector 2, a rack 3, a clamp base 4, a connecting rod big-end hole clamp 7 and a rod body clamp 8; the connecting rod 5 is arranged on the upper surface of the clamp base 4, and the lower parts of the connecting rod big-end hole clamp 7 and the rod body clamp 8 are connected with the clamp base 4.

[0051] The rack 3 is connected to the lower surface of the clamp base 4, the roundness detector 2 is connected to the upper part of the rack 3, and one end of the rack 3 is electrically connected to the computer 1.

[0052] The connecting rod big-end hole clamp 7 comprises a positioning block 71 and a positioning block track, the positioning block track is slidably connected with the lower part of the positioning block 71, and the positioning block 71 can slide along the positioning block track to limit the movement freedom degree of the connecting rod 5.

[0053] The rod body clamp 8 comprises a clamping block 81 and a clamping block track, the lower part of the clamping block 81 is slidably connected with the clamping block track, and the clamping block 81 can slide along the clamping block track to limit the rotation freedom degree of the connecting rod 5.

[0054] The roundness detector 2 detects the roundness data of the inner surface of the bushing and transmits the roundness data to the computer 1 for processing and analysis.

[0055] The embodiment is different from the first embodiment in that:

[0056] The single positioning block 71 and the single positioning block track form a positioning assembly, the connecting rod big-end hole clamp 7 comprises a plurality of positioning assemblies, each positioning block 71 moves on the respective positioning block track at an equal speed to the direction close to the inner surface of the connecting rod big-end hole, and stops after touching the inner wall of the big-end hole to limit the translational movement of the connecting rod 5.

[0057] The clamping block 81 and the clamping block track form a clamping assembly, the rod body clamp 8 comprises a plurality of clamping assemblies, the plurality of clamping assemblies are symmetrically arranged about the connecting rod body, the clamping block 81 moves along the clamping block track to the direction close to the connecting rod body to clamp the connecting rod, thereby limiting the rotation of the connecting rod and completing the positioning of the connecting rod.

[0058] The roundness detector 2 comprises a probe 6, the probe 6 is arranged above the clamp base 4, and the upper end of the probe 6 is connected with the rack 3.

[0059] The positioning block track is arranged in the interior of the clamp base 4; the positioning block track can also be a slide rail connected to the upper surface of the clamp base 4.

[0060] The clamping block track is arranged in the interior of the clamp base 4; the clamping block track can also be a slide rail connected to the upper surface of the clamp base 4.

[0061] The working process of the device for detecting the roundness of the connecting rod bushing is as follows:

[0062] The connecting rod 5 is arranged on the upper surface of the clamp base 4, the connecting rod big end hole clamp 7 is arranged in the connecting rod big end hole, and the rod body clamp 8 is arranged on both sides of the rod body of the connecting rod 5.

[0063] First, the connecting rod 5 is placed on the clamp base 4, the connecting rod big end hole clamp 4 is located in the big end hole of the connecting rod 5, and the rod body clamp 8 is symmetrically arranged on both sides of the rod body of the connecting rod 5.

[0064] Then the positioning block 71 of the connecting rod big end hole clamp 4 moves at an equal speed on the respective positioning block track to the direction close to the inner surface of the connecting rod big end hole, and stops after touching the inner wall of the big end hole.

[0065] Then the clamping block 81 of the rod body clamp 8 moves along the respective clamping block track to the direction close to the connecting rod rod body, clamps the connecting rod, and completes the positioning of the connecting rod.

[0066] After positioning, the roundness detector 2 starts to work. The roundness detector 2 is connected with the rack 3 and can move in the up-down direction and the left-right direction. Through the movement of the roundness detector 2, the probe 6 contacts the inner surface of the bushing 9 at a certain height. At this height, the probe moves along the inner hole of the bushing 9 for one round to obtain the roundness data of the inner hole of the bushing 9 at this height. Then the height is adjusted to collect the roundness data of the inner hole of the bushing 9 at different heights.

[0067] The roundness detector 2 transmits the measured roundness data to the computer 1 for further processing.

[0068] The device for detecting the roundness of the connecting rod bushing can limit the translational movement of the connecting rod 5 by arranging the positioning block and the positioning block track. The device can limit the rotation of the connecting rod 5 by arranging the clamping block 81 and the clamping block track, and moving the clamping block 81 along the clamping block track to the direction close to the connecting rod rod body to clamp the connecting rod. The positioning accuracy of the connecting rod 5 is improved, the movement detection of the probe 6 in the inner hole of the bushing 9 is facilitated, and the accuracy of the measured roundness data is improved. The device can also adjust the movement distance of the positioning block and the clamping block according to connecting rods of different sizes to meet the clamp requirements in multiple scenes.

[0069] Embodiment 3:

[0070] As shown in Figure 3 The method for detecting the roundness of the connecting rod bushing provided by the present embodiment comprises the following steps:

[0071] Step S1. First, place the connecting rod 5 assembled with the bushing 9 on the clamp base 4.

[0072] Step S2. Position the connecting rod using the connecting rod big hole clamp 4 and the rod body clamp 8;

[0073] Step S3. Collect the roundness data of the inner surface of the bushing 9 using the roundness detector 2;

[0074] Step S4. Transmit the collected roundness data to the computer 1 for processing and analysis.

[0075] Example 4:

[0076] As shown in the figure, the present embodiment provides a method for detecting the roundness of the connecting rod bushing, which comprises the following steps: Figure 3

[0077] Step S1. First, place the connecting rod 5 assembled with the bushing 9 on the clamp base 4;

[0078] Step S2. Position the connecting rod using the connecting rod big hole clamp 4 and the rod body clamp 8;

[0079] Step S3. Collect the roundness data of the inner surface of the bushing 9 using the roundness detector 2;

[0080] Step S4. Transmit the collected roundness data to the computer 1 for processing and analysis.

[0081] In the step S3, the roundness detector 2 collects the roundness data at different heights of the inner surface of the bushing 9.

[0082] In the step S4, the processing and analysis of the roundness data by the computer 1 comprises the following steps:

[0083] Step H1: Establish a three-dimensional bushing model A1 using the roundness data;

[0084] Step H2: Establish a standard bushing model A2 based on a bushing that has not been assembled and has not been deformed;

[0085] Step H3: Select sampling points at the same positions on the three-dimensional bushing model A1 and the standard bushing model A2, and calculate the displacement δ of the corresponding points;

[0086] Step H4: Compare the displacement δ with the threshold value λ of the deformation of the connecting rod. If the displacement δ is greater than the threshold value λ of the deformation of the connecting rod, it is determined that the sampling point is fitted;

[0087] Step H5: Calculate the ratio of the number of fitted sampling points to the total number of sampling points, which is the degree of fit.

[0088] Since the bushing is a thin-walled part, the inner and outer circle deformation is considered approximately equal. Here, the roundness data of the inner surface of the bushing is collected, and a three-dimensional bushing model A1 is established, thereby obtaining the roundness data of the outer circle of the bushing. ​

[0089] The threshold value λ of the deformation amount of the connecting rod 5 of different sizes is determined by experience or measured by experiment; the standard bushing model A2 needs to correspond to the size of the connecting rod bushing of different models; the detection process is as follows: the surface of the matched parts is actually two uneven surfaces in microcosm, and the matching is actually the contact of points. The connecting rod 5 and the bushing 9 are shrink fit, and the shrink fit will cause the deformation of the material. When the deformation amount is greater than the distance between two points, it can be judged that the two points have achieved contact. In addition, since the bushing 9 is a thin-walled cylindrical part, the deformation amount of the inner circular surface of the bushing 9 is equal to that of the outer circular surface, so although the data of the inner circular surface of the bushing 9 is measured here, it can be approximately equal to the data of the outer circular surface of the bushing 9 and be used for the three-dimensional modeling of the next fitting surface.

[0090] The present application provides a method for detecting the fitting degree of the connecting rod bushing, which does not need to damage the integrity of the connecting rod bushing, reduces the economic loss, and can detect all products to improve the yield; avoids the error of manual judgment, improves the detection quality and efficiency; the fitting degree is judged by detecting the roundness of the inner circular surface of the bushing 9, which improves the detection accuracy.

[0091] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application is included in the protection scope of the present application.

Claims

1. A method of detecting roundness of a connecting rod bushing fit, characterized by, The device for detecting the roundness of a connecting rod bushing includes the following steps: Step S1: Place the connecting rod with the bushing on the fixture base; Step S2: Position the connecting rod using the connecting rod big-end hole fixture and the rod body fixture; Step S3: Collect roundness data of the inner surface of the bushing using the roundness detector; Step S4: Transmit the collected roundness data to the computer for processing and analysis to calculate the fit degree; The device for detecting the roundness of a connecting rod bushing includes a computer, a roundness detector, a rack, a fixture base, a connecting rod big-end hole fixture, and a rod body fixture; The connecting rod is arranged on the upper surface of the fixture base, and the lower parts of the connecting rod big-end hole fixture and the rod body fixture are connected with the fixture base; The rack is connected to the lower surface of the fixture base, the roundness detector is connected to the upper part of the rack, and one end of the rack is electrically connected to the computer; The connecting rod big-end hole fixture includes positioning blocks and positioning block tracks, the positioning block tracks are slidably connected to the lower parts of the positioning blocks, and the positioning blocks can slide along the positioning block tracks; The rod body fixture includes clamping blocks and clamping block tracks, the lower parts of the clamping blocks are slidably connected to the clamping block tracks, and the clamping blocks can slide along the clamping block tracks; The roundness detector is used to detect the roundness data of the inner surface of the bushing and transmit it to the computer for processing and analysis.

2. The method of roundness checking the fit of a connecting rod bushing of claim 1 wherein, The connecting rod big-end hole fixture includes multiple positioning blocks and multiple positioning block tracks.

3. The method of roundness checking the fit of a connecting rod bushing of claim 1 wherein, The rod body fixture includes multiple clamping blocks and multiple clamping block tracks.

4. The method of roundness checking the fit of a connecting rod bushing of claim 1 wherein, The roundness detector includes a probe, which is arranged above the fixture base and connected to the rack at the upper end.

5. The method of roundness checking the fit of a connecting rod bushing of claim 1 wherein, The positioning block tracks are connected to the upper surface of the fixture base.

6. The method of roundness checking the fit of a connecting rod bushing of claim 1 wherein, The clamping block tracks are connected to the upper surface of the fixture base.

7. The method of roundness checking the fit of a connecting rod bushing of claim 1 wherein, The rack has an L-shaped structure.

8. The method of roundness checking the fit of a connecting rod bushing of claim 1 wherein, In step S3, the roundness detector collects roundness data at different heights of the inner surface of the bushing.

9. The method of roundness checking the fit of a connecting rod bushing of claim 1 wherein, In step S4, the computer processing and analysis of the roundness data includes the following steps: Step H1: Establish a three-dimensional bushing model A1 using the roundness data; Step H2: Establish a standard bushing model A2 based on a bushing that has not been assembled and has not been deformed; Step H3: Select sampling points at the same positions on the three-dimensional bushing model A1 and the standard bushing model A2, and calculate the displacement δ of the corresponding points; Step H4: Compare the displacement δ with the threshold value λ of the deformation of the connecting rod. If the displacement δ is greater than the threshold value λ of the deformation of the connecting rod, it is determined that the sampling point is fit; Step H5: Calculate the ratio of the number of fit sampling points to the total number of sampling points, which is the fit degree.

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