A device for detecting the straightness of the inner circular axis center line of an oil cylinder
Patent Information
- Application Number
- CN202522474433.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-21
- Publication Date
- 2026-09-29
- Estimated Expiration
- 2035-11-21
AI Technical Summary
[0003]传统的直线度检测方法如“重力法”、“钢丝直线法”等都不能很好的运用到油缸内圆轴心线直线度的检测中，刀口平尺检测油缸内圆母线直线度，且通过透光法目测和塞尺检测，几乎不可行，况且母线的直线度检测不能很好的反映油缸实体包容
1.由于油缸内圆轴心线直线度检测装置在油缸内圆可以通过牛眼轴承沿圆周滑动，且靠重力能自动帮助数字传输千分表找到中心最低点，使得数字传输千分表的检测点正好位于两对称牛眼轴承的中心线上，所以数字传输千分表的检点总是处在最低点位置，油缸内圆轴心线直线度检测装置的检测基准是两头端内圆的圆心连成的直线，使得油缸内圆轴心线直线度检测装置的检测基准更合理。检测过程中，重力方向上的弯曲带来直线度误差和重力法向上的弯曲所造成的测量误差均可抵消，因此在油缸内测量直线度对表面粗糙度的要求不高，可对油缸半成品进行检测，可以跟踪油缸的粗加工和精加工环节，质量控制范围广。
Smart Images
Figure CN224815619U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of straightness detection technology, specifically a device for detecting the straightness of the centerline of the inner circle of a hydraulic cylinder. Background Technology
[0002] A hydraulic cylinder, also known as a hydraulic cylinder, is a linear motion actuator whose output force is directly proportional to the effective area of the piston and the pressure difference between its two sides. During the machining of hydraulic cylinders, it is necessary to check the straightness of the inner cylindrical axis. Straightness testing can display the actual shape of straight elements on the workpiece and its relationship to the ideal straight line.
[0003] Traditional straightness testing methods, such as the "gravity method" and the "steel wire straightness method," cannot be well applied to the straightness testing of the inner circle axis of the hydraulic cylinder. Using a knife-edge straightedge to test the straightness of the inner circle generatrix of the hydraulic cylinder, as well as visual inspection by light transmission and feeler gauge testing, is almost impossible. Moreover, the straightness testing of the generatrix cannot accurately reflect the physical containment of the hydraulic cylinder.
[0004] Therefore, in view of this, we have studied and improved the existing structure and its shortcomings, and proposed a device for detecting the straightness of the inner cylindrical shaft. Utility Model Content
[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a device for detecting the straightness of the inner cylindrical shaft centerline of a hydraulic cylinder.
[0006] To achieve the above objectives, this utility model provides the following technical solution: a detection device for detecting the straightness of the inner cylindrical shaft centerline of a hydraulic cylinder, comprising a detection bracket, a guide rail, and a digital transmission dial indicator. Rollers are rotatably mounted on both the upper left and right sides of the detection bracket, and a hydraulic cylinder is installed on the upper side of the rollers. A guide rail is installed inside the hydraulic cylinder, and a first guide rail base and a second guide rail base that can move left and right are respectively installed at both ends of the guide rail. A dial indicator slide is slidably mounted on the outer side of the guide rail, and a digital transmission dial indicator and a wireless signal transmitter are installed on one side of the dial indicator slide.
[0007] Furthermore, an electrical control box and an electrical transmission mechanism are installed on one side of the second guide rail base, and a balance pendulum is installed on the outside of the end of the guide rail near the second guide rail base.
[0008] Furthermore, a transmission rope is connected to one side of the electro-electric mechanism, and the transmission rope is located on the outer surface of the guide rail.
[0009] Furthermore, the digital transmission dial indicator is equipped with a wireless transmission module for wireless remote control and wireless transmission of data to a computer, enabling real-time transmission of measurement data.
[0010] Furthermore, symmetrical bullseye bearings are provided on the lower side of both the first guide rail base and the second guide rail base, and the guide rail slides along the circumference of the inner circle of the oil cylinder through the bullseye bearings.
[0011] Compared with the prior art, the present invention has the following beneficial effects: 1. Because the straightness testing device for the inner cylinder's shaft centerline can slide along the circumference of the cylinder via bullseye bearings, and gravity automatically helps the digital transmission dial indicator find the lowest center point, the dial indicator's testing point is precisely located on the centerline of the two symmetrical bullseye bearings. Therefore, the digital transmission dial indicator's testing point is always at the lowest point. The testing benchmark for the cylinder's inner cylinder shaft centerline straightness testing device is the straight line connecting the centers of the inner circles at both ends, making the testing benchmark more reasonable. During the testing process, the straightness error caused by bending in the direction of gravity and the measurement error caused by bending in the normal direction of gravity can be canceled out. Therefore, the surface roughness requirement for measuring straightness inside the cylinder is not high. It can be used to inspect semi-finished cylinders, and can track the roughing and finishing stages of the cylinder, providing a wide range of quality control.
[0012] 2. The first and second guide rail bases move left and right along the guide rails, thereby adjusting the detection stroke. The detection length of the hydraulic cylinder can be arbitrarily adjusted, facilitating on-site hydraulic cylinder testing in the workshop. The electrical control box provides power for the sliding of the dial indicator slide and the digital transmission dial indicator, and can achieve stepless speed regulation and forward and reverse sliding. The transmission rope moves the digital transmission dial indicator along the guide rail. The forward and backward sliding of the digital transmission dial indicator can wirelessly transmit the collected data to the computer in real time, thereby enabling real-time transmission of measurement data and detection of the straightness of the inner cylindrical axis of the hydraulic cylinder. The node distance depends on the length of the hydraulic cylinder. Then, the data of each node is statistically analyzed. The statistics of N nodes can be combined to reflect the three-dimensional change of the inner cylindrical axis of the hydraulic cylinder, providing a more accurate and comprehensive data reference for the axial straightness accuracy quality analysis and control of the hydraulic cylinder. Attached Figure Description
[0013] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a partial structural schematic diagram of the present invention; Figure 3 for Figure 2 Enlarged view of point A in the middle; Figure 4 for Figure 2 Enlarged view of point B in the middle; Figure 5 This is a test data table for an embodiment of the present invention; Figure 6 This is a schematic diagram showing the change of the center line of the X-axis plane of the inner circle of the oil cylinder in an embodiment of this utility model; Figure 7 This is a schematic diagram showing the change of the center line of the Y-axis plane of the inner circle of the oil cylinder in an embodiment of this utility model; Figure 8 This is a schematic diagram of the four quadrant points of the hydraulic cylinder of this utility model.
[0014] In the diagram: 1. Testing bracket; 2. Roller; 3. First guide rail base; 4. Second guide rail base; 5. Electrical control box; 6. Electrical transmission mechanism; 7. Balance pendulum; 8. Guide rail; 9. Transmission rope; 10. Dial indicator slide; 11. Digital transmission dial indicator; 12. Wireless signal transmitter; 13. Bullseye bearing. Detailed Implementation
[0015] The implementation method of this utility model will be further described in detail below with reference to the accompanying drawings and embodiments.
[0016] Please see Figure 1-4 This embodiment of a cylinder inner circle axis straightness detection device includes a detection bracket 1, a guide rail 8 and a digital transmission dial indicator 11. Rollers 2 are rotatably mounted on the upper left and right sides of the detection bracket 1, and a cylinder is provided on the upper side of the rollers 2. The guide rail 8 is placed inside the cylinder, and a first guide rail base 3 and a second guide rail base 4 that can move left and right are respectively installed at both ends of the guide rail 8. Symmetrical bullseye bearings 13 are provided on the lower side of the first guide rail base 3 and the second guide rail base 4. The guide rail 8 can slide along the circumference of the inner circle of the cylinder through the bullseye bearings 13.
[0017] Because the straightness detection device for the inner circle axis of the hydraulic cylinder can slide along the circumference of the cylinder via the bullseye bearing 13 of the guide rail fixing seat, and gravity automatically helps the digital transmission dial indicator 11 find the lowest point of the center, the detection point of the digital transmission dial indicator 11 is exactly located on the center line of the two symmetrical bullseye bearings 13, so the detection point of the digital transmission dial indicator 11 is always at the lowest point. The detection benchmark of the straightness detection device for the inner circle axis of the hydraulic cylinder is the straight line connecting the centers of the inner circles at both ends, making the detection benchmark of the straightness detection device for the inner circle axis of the hydraulic cylinder more reasonable. During the detection process, the straightness error caused by bending in the direction of gravity and the measurement error caused by bending in the direction of gravity can be canceled out. Therefore, the requirements for surface roughness are not high when measuring straightness inside the hydraulic cylinder. It can be used to inspect semi-finished hydraulic cylinders and can also track the roughing and finishing processes of the hydraulic cylinder, with a wide range of quality control.
[0018] A dial indicator slide 10 is slidably mounted on the outer side of the guide rail 8, and a digital transmission dial indicator 11 and a wireless signal transmitter 12 are mounted on one side of the dial indicator slide 10. An electronic control box 5 and an electronic transmission mechanism 6 are mounted on one side of the second guide rail base 4, and a balance pendulum 7 is mounted on the outer side of the guide rail 8 near the second guide rail base 4. A transmission rope 9 is connected to one side of the electronic transmission mechanism 6, and the transmission rope 9 is located on the outer surface of the guide rail 8. The digital transmission dial indicator 11 is equipped with a wireless transmission function module for wireless remote control and wireless transmission of data to a computer, transmitting measurement data in real time.
[0019] The inner cylindrical axis of the hydraulic cylinder is a virtual spatial line that can only be measured indirectly. By collecting data from various measurement points, the trend of the inner cylindrical axis is depicted, and its straightness or curvature is determined. The detection equipment has a simpler structure, lighter weight, and is easier to operate than optical detectors. The first guide rail base 3 and the second guide rail base 4 can move left and right along the guide rail 8 to adjust the detection stroke. The detection length of the hydraulic cylinder can be arbitrarily adjusted, facilitating on-site detection of hydraulic cylinders in the workshop. The electrical control box 5 provides the power for the sliding of the dial indicator slide 10 and the digital transmission dial indicator 11, and can realize stepless speed regulation and forward and reverse sliding. The transmission rope 9 moves the digital transmission dial indicator 11 to slide along the guide rail 8. The forward and backward sliding of the digital transmission dial indicator 11 can wirelessly transmit the collected data to the computer in real time, thereby enabling real-time transmission of measurement data and detection of the straightness of the inner cylindrical axis of the hydraulic cylinder. The node distance depends on the length of the hydraulic cylinder. Then, the data of each node is statistically analyzed. The statistics of N nodes can be combined to reflect the three-dimensional changes of the inner cylindrical axis of the hydraulic cylinder, providing a more accurate and comprehensive data reference for the axial straightness accuracy quality analysis and control of the hydraulic cylinder.
[0020] The detection device of this utility model achieves detection using the following method and steps: S1. Place the cylinder to be tested on the upper side of the roller 2 for rotating the cylinder body above the test bracket 1, and put the straightness testing device composed of the first guide rail base 3, the second guide rail base 4 and the guide rail 8 into the cylinder. S2. Mark four quadrant points +X, +Y, -X, and -Y on the end face of the cylinder to represent four points tested along the circumference. Set N nodes along the length direction, with each node being a test node at every other distance. Mark them with numbers to make the distance between adjacent nodes the same. With N nodes, the cylinder is divided into N-1 equal parts. S3. When the oil cylinder zeros the digital transmission dial indicator 11 at the first node, the motor of the electric transmission mechanism 6 drives the dial indicator slide 10 and the digital transmission dial indicator 11 to move along the guide rail 8 inside the oil cylinder. S4. Rotate the oil cylinder and record the readings of the digital transmission dial indicator 11 at the four points of +X, +Y, -X, -Y at the first node one by one, so that the digital transmission dial indicator 11 automatically transmits the readings to the computer EXCEL spreadsheet through the wireless signal transmitter 12. S5. The digital transmission dial indicator 11 moves gradually to the second node, the third node, the fourth node, and the (N-1)th node. During this process, it repeatedly records the readings of the four points +X, +Y, -X, and -Y at each node and performs wireless data transmission. S6. Statistically analyze the data of each node. The data difference in the +X and -X directions reflects the eccentricity of the inner cylinder axis in the X-axis plane, and the data difference in the +Y and -Y directions reflects the eccentricity of the inner cylinder axis in the Y-axis plane. S7. Connect the statistics of N nodes into a curve, and use EXCEL software to create a graph showing the change of the center line of the inner circle of the cylinder in the X-axis and Y-axis planes. This graph represents the two-dimensional change of the center line of the inner circle of the cylinder. Visualize the graph and finally determine the axial step change of the overall straightness of the cylinder body under the containment of the cylinder by the curve trend of the rough and fine machining error of the center line of the inner circle in the X-axis and Y-axis planes.
[0021] Specifically, consider the following data as an example: S1. Place the cylinder to be tested on the upper side of the roller 2 for rotating the cylinder body above the test bracket 1, and put the straightness testing device composed of the first guide rail base 3, the second guide rail base 4 and the guide rail 8 into the cylinder. The length of the cylinder is 2000mm. S2. Mark four quadrant points (+X, +Y, -X, -Y) on the end face of the cylinder to indicate four test points along the circumference. Set five nodes along the length direction, with each node spaced 500mm apart. Each node is a test node, marked with numbers to ensure that the distance between adjacent nodes is the same. With five nodes, the cylinder is divided into four equal parts. S3. When the oil cylinder zeros the digital transmission dial indicator 11 at the first node, the motor of the electric transmission mechanism 6 drives the dial indicator slide 10 and the digital transmission dial indicator 11 to move along the guide rail 8 inside the oil cylinder. S4. Rotate the oil cylinder and record the readings of the digital transmission dial indicator 11 at the four points of +X, +Y, -X, -Y at the first node one by one, so that the digital transmission dial indicator 11 automatically transmits the readings to the computer EXCEL spreadsheet through the wireless signal transmitter 12. S5. The digital transmission dial indicator 11 moves gradually to the second node, the third node, the fourth node, and the (N-1)th node. During this process, it repeatedly records the readings of the four points +X, +Y, -X, and -Y at each node and performs wireless data transmission. S6. Statistically analyze the data of each node. The data difference in the +X and -X directions reflects the eccentricity of the inner cylinder axis in the X-axis plane, and the data difference in the +Y and -Y directions reflects the eccentricity of the inner cylinder axis in the Y-axis plane. The bending of the guide rail in a straightness testing device will introduce errors into the straightness measurement. One manifestation of this error is the bending in the direction of gravity. What we need are the differences between the +X and -X directions and the +Y and -Y directions. These differences reflect the center deviation at a certain point, as shown below: Measured data D1 of dial indicator in the +X direction at a certain node - guide rail error T = true value M1 Measured data D3 of dial indicator in the X direction at a certain node - guide rail error T = true value M3 M3-M1=(D3-T)-(D1-T) is the eccentricity of the center of a circle at a certain point in the X-axis direction; The guide rail error T is canceled out in the equation and will not affect the measurement results. Secondly, the upward bending is manifested by gravity, but this measurement error is reflected in the fact that the trajectory of the dial indicator's detection point sometimes deviates from the lowest point of the center. The effect of this error can also be offset and has no impact on the test results.
[0022] like Figure 5 As shown, the data analysis for the first node is as follows: The center offset in the X-axis direction is (0.01-0.02) / 2=-0.005, meaning the center is offset 0.005mm in the -X direction. The center offset in the Y-axis direction is (0.03-0) / 2=0.015, meaning the center is offset 0.015mm in the +Y direction. like Figure 5 As shown, the data analysis for the second node is as follows: The center offset in the X-axis direction is (0.42-0.51) / 2=-0.045, meaning the center is offset 0.045mm in the -X direction. The center offset in the Y-axis direction is (0.53-0.4) / 2=0.065, meaning the center is offset 0.065mm in the +Y direction. like Figure 5 As shown, the data analysis for the third node is as follows: The center offset in the X-axis direction is (0.16-0.22) / 2=-0.03, meaning the center is offset 0.03mm in the -X direction. The center offset in the Y-axis direction is (0.24-0.1) / 2=0.07, meaning the center is offset 0.07mm in the +Y direction. like Figure 5 As shown, the data analysis for the fourth node is as follows: The center offset in the X-axis direction is (-0.17 - (-0.16)) / 2 = -0.005, meaning the center is offset 0.005 mm in the -X direction. The center offset in the Y-axis direction is (-0.13-(-0.21)) / 2=-0.04, and the center is offset 0.04mm in the +Y direction; like Figure 5 As shown, the data analysis for the fifth node is as follows: The center offset in the X-axis direction is (-0.16 - (-0.14)) / 2 = -0.01, and the center is offset 0.045 mm in the -X direction; The center offset in the Y-axis direction is (-0.15 - (-0.14)) / 2 = -0.005, meaning the center is offset 0.005 mm in the -Y direction. S7. Connect the statistics of N nodes into a curve, and use EXCEL software to create a graph of the change of the center line of the inner circle of the cylinder in the X-axis plane and Y-axis plane, which represents the two-dimensional change of the center line of the inner circle of the cylinder. Visualize it, and finally judge the axial step change of the overall straightness under the containment of the cylinder body by the curve trend of the rough and fine machining error of the center line of the inner circle in the X-axis plane and Y-axis plane. The diagram showing the changes in the centerlines of the X-axis and Y-axis planes of the inner circle of the hydraulic cylinder, created using Excel software, is shown below. Figure 6 , Figure 7 As shown, it can be seen that the difference between the +Y and -Y directions of this hydraulic cylinder gradually increases at the first node, reaches its maximum at the third node, and then gradually decreases at the fourth and fifth nodes. Therefore, it can be concluded that the projection of the inner cylinder's centerline onto the Y-axis plane is an arc (see...). Figure 7 The straightness error is taken as the maximum value of 0.07 mm at 3 nodes; the projection on the X-axis plane is a curve (see...). Figure 6 The straightness error is 0.045mm. Therefore, by observing the curve trend of the rough and finish machining error of the inner circle centerline in the X-axis and Y-axis planes, the axial step change of the overall straightness under the containment of the cylinder can be determined, providing a more accurate and comprehensive data reference for the axial straightness accuracy quality analysis and control of the cylinder.
[0023] In summary, please refer to Figures 1 to 8The method and device for detecting the straightness of the inner circular axis of the hydraulic cylinder are described. In use, the hydraulic cylinder to be tested is first placed on the roller 2 above the testing bracket 1 for rotating the cylinder body. The straightness detection device, consisting of the first guide rail base 3, the second guide rail base 4, and the guide rail 8, is then placed into the cylinder. Next, four quadrant points (+X, +Y, -X, -Y) are marked on the cylinder end face, representing four points along the circumference. N nodes are set along the length direction, with each node representing a test point, marked digitally to ensure that adjacent nodes are at equal distances. With N nodes, the cylinder is divided into N-1 equal parts. At the first node, the digital transmission dial indicator 11 is zeroed, causing the motor of the electric transmission mechanism 6 to drive the dial indicator slide 10 and the digital transmission dial indicator 11 to move along the guide rail 8 inside the cylinder. Then, the cylinder is rotated, and the readings of the digital transmission dial indicator 11 at the four points (+X, +Y, -X, -Y) at the first node are recorded sequentially. 11 The readings are automatically transmitted to an Excel spreadsheet on a computer via a wireless signal transmitter 12; the digital transmission dial indicator 11 moves step by step to the second node, the third node, the fourth node, and the (N-1)th node, repeatedly recording the readings at the four points (+X, +Y, -X, -Y) at each node and transmitting the data wirelessly; the data at each node is statistically analyzed, the data difference in the +X and -X directions reflects the eccentricity of the cylinder's inner circle axis in the X-axis plane, and the data difference in the +Y and -Y directions reflects the eccentricity of the cylinder's inner circle axis in the Y-axis plane; the statistics of the N nodes are connected into a curve, and an EXCEL software is used to create a graph showing the change of the cylinder's inner circle axis in the X-axis and Y-axis planes, representing the two-dimensional change of the cylinder's inner circle axis, which is then visualized. Finally, the axial step change of the overall straightness under the cylinder's containment is determined by the curve trend of the roughing and finishing errors of the inner circle's axis in the X-axis and Y-axis planes.
[0024] The device for detecting the straightness of the inner cylinder shaft centerline can guide the optimization of the cylinder scraper process. Specifically, it involves monitoring the feasibility of deformation caused by stress on the cylinder due to machining speed and feed, helping the technical department to formulate strict machining parameter standards. Furthermore, the detection data can guide the optimization of the cylinder material heat treatment process, explore the relationship between cylinder hardness and cylinder straightness, and explore how to balance hardness with the economic benefits of the process. Moreover, the detection data can optimize the selection of cylinder materials, providing a new reference coefficient for the relationship between cylinder materials and cylinder quality, and providing a more comprehensive explanation of cylinder quality and failures.
[0025] The embodiments of this utility model are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the utility model to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical applications of this utility model, and to enable those skilled in the art to understand this utility model and design various embodiments with various modifications suitable for a particular purpose.
Claims
1. A device for detecting the straightness of the inner cylindrical shaft centerline of a hydraulic cylinder, characterized in that, The device includes a testing bracket (1), a guide rail (8), and a digital transmission dial indicator (11). Rollers (2) are rotatably mounted on the upper left and right sides of the testing bracket (1), and a hydraulic cylinder is placed on the upper side of the rollers (2). The guide rail (8) is placed inside the hydraulic cylinder, and a first guide rail base (3) and a second guide rail base (4) are respectively installed at both ends of the guide rail (8). A dial indicator slide (10) is slidably mounted on the outer side of the guide rail (8), and a digital transmission dial indicator (11) and a wireless signal transmitter (12) are installed on one side of the dial indicator slide (10).
2. The device for detecting the straightness of the inner cylindrical shaft centerline according to claim 1, characterized in that, An electrical control box (5) and an electrical transmission mechanism (6) are installed on one side of the second guide rail base (4), and a balance pendulum (7) is installed on the outside of the guide rail (8) near the second guide rail base (4).
3. The device for detecting the straightness of the inner cylindrical shaft centerline according to claim 2, characterized in that, The electric transmission mechanism (6) is connected to a transmission rope (9) on one side, and the transmission rope (9) is located on the outer surface of the guide rail (8).
4. The device for detecting the straightness of the inner cylindrical shaft centerline according to claim 3, characterized in that, The digital transmission dial indicator (11) is equipped with a wireless transmission function module for wireless remote control and wireless transmission of data to a computer, transmitting measurement data in real time.
5. The device for detecting the straightness of the inner cylindrical shaft centerline according to claim 1, characterized in that, Symmetrical bullseye bearings (13) are provided on the lower side of both the first guide rail base (3) and the second guide rail base (4).