Non-standard plunger hydraulic cylinder repair test method

Abstract

The invention discloses a non-standard plunger hydraulic cylinder repair test method, which comprises the following steps of: measuring a first diameter of a target part where a plunger and a guide belt slide, measuring a target thickness of the guide belt, and measuring a second diameter of a cylinder body guide belt mounting groove; according to the first diameter, the target thickness and the second diameter, a guide belt gasket needing to be added is calculated; assembling the plunger hydraulic cylinder, and installing the plunger hydraulic cylinder on test equipment for calibration; performing a leakage test, a buffer test, a pressure resistance test and a durability test on the calibrated plunger hydraulic cylinder under low pressure; and the plunger hydraulic cylinder friction plate is taken out, and the oil leakage condition on the oil absorption paper is checked so as to judge the performance of the plunger hydraulic cylinder. Thus, when the plunger and the guide belt in the sealing assembly are abraded, and the radial holding force of the guide belt on the plunger is reduced, leakage caused by radial acting force is treated. And oil leakage of the plunger hydraulic cylinder can be accurately detected under the conditions that the working frequency of the plunger hydraulic cylinder is relatively high and the detection difficulty is relatively large.

Description

Technical Field

[0001] The present invention relates to the technical field of rolling mills, and particularly to a repair and test method for a non-standard plunger hydraulic cylinder. Background Art

[0002] The main drive screw-down system of a medium and heavy plate reversing rolling mill uses a non-standard plunger hydraulic cylinder for the adjustment and control of the mechanical roll gap. Due to the high rolling frequency, the roll gap adjustment frequency is also high, and the plunger hydraulic cylinder needs to work up to 300 - 400 times per hour. The frequent operation will inevitably cause rapid wear of the plunger and the guide band of the plunger hydraulic cylinder. At the same time, during the process of rolling steel plates, the plunger hydraulic cylinder needs to bear the radial force, and relative movement occurs between the plunger and components such as the lip seal and the guide band, which easily causes problems such as leakage, high replacement frequency of the plunger hydraulic cylinder, high maintenance cost, and environmental pollution. Summary of the Invention

[0003] In view of the above problems, the present invention provides a repair and test method for a non-standard plunger hydraulic cylinder, which is used to repair the wear of the plunger of the plunger hydraulic cylinder and the guide band in the seal assembly after long-term use, and at the same time test the leakage performance of the plunger hydraulic cylinder.

[0004] According to the first aspect of the present invention, a repair and test method for a non-standard plunger hydraulic cylinder is provided, including:

[0005] Measuring the first diameter of the target part where the plunger and the guide band slide, measuring the target thickness of the guide band, and measuring the second diameter of the guide band installation groove of the cylinder body;

[0006] Calculating the guide band gasket to be added according to the first diameter, the target thickness, and the second diameter;

[0007] Assembling the plunger hydraulic cylinder and installing it on the test equipment for calibration;

[0008] Conducting a leakage test, a buffer test, a pressure resistance test, and a durability test on the calibrated plunger hydraulic cylinder under low pressure;

[0009] Taking out the friction plate of the plunger hydraulic cylinder and checking the oil seepage condition on the oil absorption paper to judge the performance of the plunger hydraulic cylinder.

[0010] Optionally, the measuring the first diameter of the target part where the plunger and the guide band slide includes:

[0011] Selecting 8 measurement points on the circumference where the target part is located respectively and multiple times to obtain the measured diameter data; wherein, the 8 measurement points are evenly distributed on the circumference of the plunger, and the included angle between each measurement point is 45 degrees;

[0012] Determine the first diameter based on the diameter data obtained from multiple measurements.

[0013] Optionally, calculating the guide belt gasket to be added according to the first diameter, the target thickness, and the second diameter includes:

[0014] Add twice the target thickness of the guide belt to the first diameter, and then subtract the second diameter to obtain the thickness of the guide belt gasket to be added.

[0015] Optionally, assembling the plunger hydraulic cylinder and installing it on the test equipment for calibration includes:

[0016] Install two plunger hydraulic cylinders opposite to each other and fasten them;

[0017] Connect the two plunger hydraulic cylinders to the inlet pipe and the return pipe of the test equipment respectively. Wrap the friction plates of the two plunger hydraulic cylinders with absorbent paper, place them at the installation position of the plunger hydraulic cylinder to be tested, and the friction plates are not connected to the cylinder block.

[0018] Optionally, the leakage test under low pressure includes:

[0019] Adjust the system pressure of the test device. At a minimum pressure of 5 kg, make the plunger hydraulic cylinder reciprocate more than 3 times, and stay at the end of each stroke for at least 10 seconds;

[0020] Extend the plunger of the first plunger hydraulic cylinder to work, switch the oil inlet and outlet directions of the test device, extend the oil supply plunger of the second plunger hydraulic cylinder to work, and retract the plunger of the first plunger hydraulic cylinder;

[0021] Check whether the plunger hydraulic cylinder vibrates and creeps during the movement;

[0022] Check whether there is oil leakage at the plunger dust seal, brake body, and oil pipe connection parts of the plunger hydraulic cylinder.

[0023] Optionally, the buffer test includes:

[0024] Adjust the test pressure of the test device to 50% of the maximum working pressure of the plunger hydraulic cylinder, run at the maximum speed of the test device, detect the reciprocating movement of the plunger hydraulic cylinder more than 10 times, and stay at the end of each stroke for at least 10 seconds, and check whether the plunger hydraulic cylinder and the oil pipe leak oil.

[0025] Optionally, the pressure resistance test includes:

[0026] Apply pressure to the working chamber for a pressure holding test for 10 minutes according to the maximum opening pressure of the plunger hydraulic cylinder;

[0027] Check whether the plunger hydraulic cylinder and the oil pipe leak oil.

[0028] Optionally, the durability test includes:

[0029] Conduct a durability test according to the highest opening pressure of the plunger hydraulic cylinder. Let the plunger of the first plunger hydraulic cylinder extend for work, switch the oil inlet and outlet directions of the test device, let the oil supply plunger of the second plunger hydraulic cylinder extend for work, retract the plunger of the first plunger hydraulic cylinder, and the number of working times of the plunger of each plunger hydraulic cylinder is greater than 500 times.

[0030] According to a second aspect of the present invention, a non-standard plunger hydraulic cylinder is provided, and the non-standard plunger hydraulic cylinder applies the aforementioned non-standard plunger hydraulic cylinder repair and test method.

[0031] According to a third aspect of the present invention, a medium-thick plate reversible rolling mill is provided, including a non-standard plunger hydraulic cylinder, and the non-standard plunger hydraulic cylinder applies the aforementioned non-standard plunger hydraulic cylinder repair and test method.

[0032] One or more of the above technical solutions in the embodiments of this specification have at least the following technical effects:

[0033] When the wear of the guide strip in the plunger and the seal assembly causes a decrease in the radial clamping force of the guide strip on the plunger after long-term use, the leakage caused by the radial acting force is treated. It is also possible to accurately detect the oil leakage of the plunger hydraulic cylinder under the condition of a high working frequency and great detection difficulty of the plunger hydraulic cylinder.

[0034] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable, the following specific embodiments of the present invention are specifically given. Brief Description of the Drawings

[0035] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. And throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0036] Figure 1 The flowchart of a non-standard plunger hydraulic cylinder repair and test method in an embodiment of the present invention is shown. Detailed Description of the Preferred Embodiments

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. The components of the embodiments of the present invention usually described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0039] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0040] In the description of the present invention, it should also be noted that unless otherwise clearly specified and defined, the terms "set", "install", "connect", and "couple" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0041] Combined with Figure 1 As shown, the present invention provides a method for repairing and testing a non-standard plunger hydraulic cylinder, and the method includes Step 101 to Step 105:

[0042] Step 101: Measure the first diameter of the target part where the plunger and the guide band slide, measure the target thickness of the guide band, and measure the second diameter of the guide band installation groove of the cylinder block.

[0043] In this embodiment, the plunger hydraulic cylinder mainly consists of 1 cylinder block, 2 plungers, 2 guide bands, 2 dust seals, 2 bellows seals, 1 friction plate, 2 springs, and 2 friction plate fixing bolts.

[0044] When measuring the first diameter of the target part of the plunger, use a micrometer to measure the diameter of the target part, select 8 measurement points, and the selected measurement points are evenly distributed on the circumference, and the angle between each measurement point is 45 degrees. Repeat the measurement 4 times, measure 4 diameter data, and then calculate the average value as the first diameter of the plunger.

[0045] Take 8 points evenly in the length direction of the guide strip for measurement, measure the thickness of the guide strip, and then calculate the average value as the target thickness of the guide strip.

[0046] Regarding the measurement of the installation groove of the cylinder block guide strip, the diameter of the installation groove of the cylinder block guide strip can be measured with a micrometer. Select 8 measurement points, which are evenly distributed on the circumference, and the included angle between each measurement point is 45 degrees. Repeat the above steps 4 times to obtain 4 measured diameter data, and then calculate the average value as the second diameter of the installation groove of the cylinder block guide strip.

[0047] Step 102: Calculate the guide strip gasket that needs to be added according to the first diameter, the target thickness, and the second diameter;

[0048] In this embodiment, add 2 times the target thickness of the guide strip to the first diameter, and then subtract the second diameter to obtain the thickness of the guide strip gasket that needs to be added. If the thickness of the guide strip gasket is too small, the radial force on the plunger is insufficient; if it is too large, the plunger cannot return by the spring force after pressure relief. It is necessary to accumulate and explore test data through multiple calibration tests.

[0049] Step 103: Assemble the plunger hydraulic cylinder and install it on the test equipment for calibration;

[0050] Assemble the plunger hydraulic cylinder and install it on the test equipment. Adjust the system pressure of the test equipment to a certain value, and test the starting pressure of the plunger hydraulic cylinder. After pressure relief, the plunger cylinder can return by the spring force. If the starting pressure is too small, it means that the radial force on the plunger is insufficient; if the starting pressure is too large, the plunger cannot return by the spring force after pressure relief. The starting pressure can be obtained through the accumulation and exploration of multiple test data.

[0051] Step 104: Conduct leakage test, buffer test, pressure resistance test, and durability test on the calibrated plunger hydraulic cylinder under low pressure;

[0052] In this embodiment, the plunger hydraulic cylinder needs to be prepared for testing before the test:

[0053] Remove the fixing bolts of the friction plate of the plunger hydraulic cylinder to separate the friction plate from the plunger hydraulic cylinder, and prepare 2 plunger hydraulic cylinders for assembly and testing together.

[0054] Test assembly:

[0055] Install 2 plunger hydraulic cylinders opposite to each other and fasten them with bolts and corresponding torques. Connect the inlet pipe and the return pipe of the test device to the 2 plunger hydraulic cylinders respectively. Wrap the friction plates of the 2 plunger hydraulic cylinders with absorbent paper and place them at the installation position of the plunger hydraulic cylinder to be tested. There is no need to connect the friction plate to the cylinder block to better observe the oil leakage situation.

[0056] Leakage test under low pressure:

[0057] Adjust the system pressure of the test device. When the minimum pressure is 5 kg, make the plunger hydraulic cylinder reciprocate more than 3 times, and stay at the end of each stroke for at least 10 seconds. Let the plunger of the first plunger hydraulic cylinder extend to work, and switch the oil inlet and outlet directions of the test device. The oil supply plunger of the second plunger hydraulic cylinder extends to work, and retract the plunger of the previous plunger hydraulic cylinder (when the machine is working, there is a friction plate between the two plunger hydraulic cylinders, and it returns to its position by the spring after pressure relief. Since it cannot return to its position by the spring after disassembly, it is necessary to use another plunger hydraulic cylinder to return to its position). The following inspections are carried out during the test:

[0058] (1) Check whether the plunger hydraulic cylinder vibrates and creeps during the movement process;

[0059] (2) Observe whether there is oil leakage at the plunger dust seal, brake body and oil pipe connection parts of the plunger hydraulic cylinder.

[0060] Buffer test:

[0061] Adjust the test pressure of the test device to 50% of the maximum working pressure (160 kg) of the plunger hydraulic cylinder, that is, 80 kg, and run at the maximum speed that the test device can provide. Detect the reciprocating movement of the plunger hydraulic cylinder for more than 10 times, and stay at the end of each stroke for at least 10 seconds. Check whether the plunger hydraulic cylinder and the oil pipe leak oil.

[0062] Pressure resistance test:

[0063] According to the maximum opening pressure of 160 kg of the plunger hydraulic cylinder, apply a pressure of 160 kg to the working chamber, and keep the pressure for 10 minutes. Check whether the plunger hydraulic cylinder and the oil pipe leak oil. After the test is completed, test the second plunger hydraulic cylinder in the same way. After both are leak-free, proceed to the next test.

[0064] Durability test:

[0065] According to the actual working conditions and the technical requirements of the plunger hydraulic cylinder, conduct the test at the maximum opening pressure of 160 kg. Let the plunger of the first plunger hydraulic cylinder extend to work, and switch the oil inlet and outlet directions of the test device. The oil supply plunger of the second plunger hydraulic cylinder extends to work, and retract the plunger of the first plunger hydraulic cylinder, ensuring that the working times of the plunger of each plunger hydraulic cylinder are greater than 500 times.

[0066] Step 105: Take out the friction plate of the plunger hydraulic cylinder, and check the oil seepage on the oil absorption paper to judge the performance of the plunger hydraulic cylinder.

[0067] After the above tests are completed, take out the friction plate of the plunger hydraulic cylinder, and observe whether there is oil seepage on the circumference of the plunger size on the oil absorption paper. If there is oil seepage, it means that the performance of the plunger hydraulic cylinder cannot meet the use requirements. If there is no oil seepage, it means that the performance of the plunger hydraulic cylinder meets the use requirements.

[0068] In summary, for a non-standard plunger hydraulic cylinder repair and test method provided by an embodiment of the present invention, when the wear ring in the plunger and the sealing assembly is worn due to long-term use and the radial clamping force of the wear ring on the plunger is reduced, the leakage caused by the radial acting force can be treated. It is also possible to accurately detect the oil leakage of the plunger hydraulic cylinder under the conditions of a relatively high working frequency and great detection difficulty of the plunger hydraulic cylinder.

[0069] Based on the same inventive concept, this embodiment also provides a non-standard plunger hydraulic cylinder, and the non-standard plunger hydraulic cylinder applies the aforementioned non-standard plunger hydraulic cylinder repair and test method. For the specific content of the method, please refer to the foregoing embodiments and will not be elaborated herein.

[0070] Based on the same inventive concept, this embodiment also provides a medium plate reversing mill, including a non-standard plunger hydraulic cylinder, and the non-standard plunger hydraulic cylinder applies the aforementioned non-standard plunger hydraulic cylinder repair and test method. For the specific content of the method, please refer to the foregoing embodiments and will not be elaborated herein.

[0071] In summary, when the wear ring in the plunger and the sealing assembly is worn due to long-term use and the radial clamping force of the wear ring on the plunger is reduced, the leakage caused by the radial acting force can be treated. It is also possible to accurately detect the oil leakage of the plunger hydraulic cylinder under the conditions of a relatively high working frequency and great detection difficulty of the plunger hydraulic cylinder.

[0072] The above are only various embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A repair and test method for a non-standard plunger hydraulic cylinder, characterized in that, Including: Measuring the first diameter of the target part where the measuring plunger slides with the guide band, measuring the target thickness of the guide band, and measuring the second diameter of the guide band installation groove of the cylinder block; Calculating the guide band gasket to be added according to the first diameter, the target thickness, and the second diameter; Assembling the plunger hydraulic cylinder and installing it on the test equipment for calibration; Conducting leakage tests, buffer tests, pressure resistance tests, and durability tests on the calibrated plunger hydraulic cylinder under low pressure; Taking out the friction plate of the plunger hydraulic cylinder and checking the oil seepage condition on the oil absorption paper to judge the performance of the plunger hydraulic cylinder.

2. The method according to claim 1, wherein The measuring the first diameter of the target part where the measuring plunger slides with the guide band includes: Selecting 8 measuring points on the circumference where the target part is located multiple times respectively to obtain the measured diameter data; among them, the 8 measuring points are evenly distributed on the circumference of the plunger, and the included angle between each measuring point is 45 degrees; Determining the first diameter according to the diameter data obtained from multiple measurements.

3. The method according to claim 1, wherein The calculating the guide band gasket to be added according to the first diameter, the target thickness, and the second diameter includes: Adding twice the target thickness of the guide band to the first diameter, and then subtracting the second diameter to obtain the thickness of the guide band gasket to be added.

4. The method according to claim 1, wherein The assembling the plunger hydraulic cylinder and installing it on the test equipment for calibration includes: Installing and fastening 2 plunger hydraulic cylinders relatively; Connecting the 2 plunger hydraulic cylinders to the inlet pipe and the return pipe of the test equipment respectively, wrapping the friction plates of the 2 plunger hydraulic cylinders with oil absorption paper, placing them at the installation position of the plunger hydraulic cylinder to be tested, and the friction plates are not connected to the cylinder block.

5. The method according to claim 1, characterized in that The leakage test under low pressure includes: Adjusting the system pressure of the test device, making the plunger hydraulic cylinder reciprocate more than 3 times at the lowest pressure of 5 kg, and staying at the stroke terminal for at least 10 seconds each time; Extending the plunger of the first plunger hydraulic cylinder to work, switching the oil inlet and outlet directions of the test device, extending the oil supply plunger of the second plunger hydraulic cylinder to work, and retracting the plunger of the first plunger hydraulic cylinder; Checking whether the plunger hydraulic cylinder vibrates and creeps during the movement process; Checking whether there is oil leakage at the plunger dust seal, brake body, and oil pipe connection part of the plunger hydraulic cylinder.

6. The method according to claim 1, wherein The buffer test includes: Adjusting the test pressure of the test device to 50% of the highest working pressure of the plunger hydraulic cylinder, running at the maximum speed of the test device, detecting the reciprocating movement of the plunger hydraulic cylinder more than 10 times, and staying at the stroke end for at least 10 seconds each time, and checking whether the plunger hydraulic cylinder and the oil pipe leak oil.

7. The method according to claim 1, characterized in that The pressure resistance test includes: Applying pressure to the working chamber for a pressure holding test for 10 minutes according to the highest opening pressure of the plunger hydraulic cylinder; [[ID= 8. The method according to claim 1, characterized in that, ​ ​ 9. A non-standard plunger hydraulic cylinder, characterized in that, The non-standard plunger hydraulic cylinder applies the repair and test method of the non-standard plunger hydraulic cylinder according to any one of claims 1-8.

10. A medium and heavy plate reversing mill, characterized in that, It includes a non-standard plunger hydraulic cylinder, and the non-standard plunger hydraulic cylinder applies the repair and test method of the non-standard plunger hydraulic cylinder according to any one of claims 1-8.

Images