Test method for detecting pressure of hydraulic oil cylinder

Abstract

The invention provides a test method for detecting the pressure of a hydraulic oil cylinder, and the method comprises the steps: injecting water into a to-be-tested oil cylinder after the to-be-tested oil cylinder is placed on a test platform, then conveying a gland main body to a position above the to-be-tested oil cylinder through a crane, enabling the gland main body to slide into the to-be-tested oil cylinder through the gravity of the gland main body, and carrying out the detection of the pressure of the to-be-tested oil cylinder. In the process, the inner side face of the to-be-tested oil cylinder extrudes the sealing ring to fill a gap between the outer side face of the second main body part and the inner side face of the oil cylinder, after the gland main body slides into the to-be-tested oil cylinder, the gland main body and the to-be-tested oil cylinder are fixed through the bolt, and then high-pressure oil is injected into the to-be-tested oil cylinder through the counterbore and the channel. After pressure maintaining is conducted for a period of time, whether water or oil leakage exists in the oil cylinder to be tested or not is detected, and then whether the oil cylinder to be tested is qualified or not is judged; the oil cylinder to be tested does not need to be additionally machined, the testing process is short in consumed time, operation is convenient, and the method is high in reliability.

Description

Technical Field

[0001] The invention relates to the technical field of hydraulic oil cylinders, and in particular to a test method for detecting the pressure of a hydraulic oil cylinder. Background Art

[0002] The hydraulic cylinder is a linear motion actuator whose output force is proportional to the effective area of ​​the piston and the pressure difference on both sides. Its function is to convert hydraulic energy into mechanical energy. In practical applications, it can realize reciprocating motion, eliminate the need for a deceleration device, and has no transmission gap and smooth movement. Therefore, it is widely used in the hydraulic systems of various machines. High-pressure hydraulic cylinders are indispensable in large-scale infrastructure equipment such as excavators and cranes, ships, marine engineering equipment and industrial equipment.

[0003] When producing the outer cylinder body accessories of the hydraulic support cylinder, it is impossible to perform pressure and pressure holding tests on the pressure test bench because they are not assembled into finished cylinder products. Therefore, it is necessary to perform necessary pressure tests on the cylinder, such as the patent document with Chinese patent application number 202221995625.2 and announcement date 2023.01.17, which discloses a combined cylinder body pressure test tool, including a plug body, a side wall of the plug body is provided with a thread matching the top thread in the cylinder body, a pressure measuring device for measuring the internal pressure of the cylinder body is provided on the plug body, and the pressure measuring device includes a pressure gauge arranged on the plug body, and the pressure gauge is connected to the inside of the tank body through a channel arranged inside the plug body, so as to ensure the pressure test effect, improve accuracy, greatly improve practicality, reduce labor intensity, and improve production efficiency.

[0004] In the above-mentioned document, when conducting a pressure test, the plug body is manually screwed to the cylinder body, and then the sealing bolt is removed, the air inside the cylinder body is discharged through the exhaust port, and hydraulic oil is filled into the cylinder body at the same time, and finally the pressure value in the cylinder is measured by a pressure gauge; however, when conducting a pressure test on a large high-pressure oil cylinder, due to the large shape and weight of the pressure test tool, the pressure test tool cannot be manually installed on the oil cylinder to be tested, and if the pressure test tool and the oil cylinder to be tested are still connected by threads, it is also necessary to perform thread processing on the oil cylinder to be tested, and wear may even be caused during the processing of the oil cylinder to be tested. This adds an extra step, a large workload, and makes the test process time-consuming. Summary of the invention

[0005] The purpose of the present invention is to provide a test method for detecting the pressure of a hydraulic cylinder, which does not require additional processing of the cylinder to be tested, has a short test process time, is easy to operate, and has high reliability.

[0006] To achieve the above purpose, a test method for detecting the pressure of a hydraulic cylinder is provided, wherein the test is realized by connecting a gland body to the upper end surface of a hydraulic cylinder to be tested, wherein the gland body comprises a first body portion and a second body portion, wherein the cross-sectional area of ​​the second body portion is smaller than the cross-sectional area of ​​the first body portion, and a first step portion is formed at the connection between the first body portion and the second body portion, wherein the first step portion is detachably connected to the top surface of the cylinder, and there is a clearance fit between the outer side surface of the second body portion and the inner side surface of the cylinder, and further comprising the following steps: S0 marks the height of the water layer in the oil cylinder to be tested, and then marks the height of the oil layer on the water layer, and the volume of the water layer is greater than the volume of the oil layer; S1: Place the oil cylinder to be tested on the test platform, and make the opening of the oil cylinder to be tested face upward vertically. Then seal the oil inlet and outlet of the oil cylinder to be tested, and inject water into the oil cylinder until the water level reaches the water layer height marked in step S0, and then stop injecting water. S2 hangs the gland body on the crane, controls the crane to transport the gland body to the top of the oil cylinder to be tested, and makes the axis of the gland body coincide with the axis of the oil cylinder to be tested; S3 controls the crane to vertically lower the gland body, and stops the crane operation when the second body part contacts the oil cylinder to be tested; S4: Under the action of the gravity of the gland body, the second body slides into the oil cylinder to be tested along the axis of the oil cylinder to be tested, so that the inner side surface of the oil cylinder to be tested squeezes the sealing ring arranged on the second body; S5 After the second main body is completely slid into the oil cylinder to be tested, the first main body is locked with the oil cylinder to be tested by passing the fastening bolts through the mounting holes provided on the first main body; S6 injects high-pressure oil into the oil cylinder to be tested through the countersunk hole and the channel provided on the first main body, and stops supplying oil after the high-pressure oil fills the oil layer height marked in step S0; S7: Maintain the pressure for a period of time T, and then check the four sides, oil inlet and outlet ports, and welding points of the tested cylinder for leakage; After the pressure test, S8 draws out the oil layer in the tested cylinder, then removes the fastening bolts on the first main body, controls the crane to lift the gland body out of the cylinder, and completes the cylinder pressure test.

[0007] The above method, by successively injecting water and oil into the oil cylinder to be tested, can first fill most of the space of the oil cylinder to be tested with water, and then fill the remaining space of the oil cylinder to be tested with oil. Since the volume passing through the crack is fixed, for the same volume of water and oil, the density of water is greater than that of oil, so the amount of water flowing out through the same volume of crack will be more than that of oil, and then it can be judged whether the oil cylinder is qualified by observing whether there is water leakage, thereby avoiding the situation where the oil remains in the crack and does not completely flow out of the crack and misjudging the oil cylinder as qualified. This makes it convenient to judge whether the oil cylinder has cracks. In addition, by first injecting water In the method of injecting oil layer, only a small amount of oil layer needs to be injected, which can reduce the amount of oil leaking, reduce pollution to the test environment and waste of hydraulic oil; after the gland body abuts against the oil cylinder to be tested, it can automatically slide into the oil cylinder to be tested under the action of its own gravity, and then fix the gland on the step surface with bolts to make it flush and achieve the sealing effect. After the test, it is urgent to tighten the bolts to realize the pressure test of another oil cylinder by the gland. The operation is convenient and time-saving, and the pressure test can be realized after the oil is injected.

[0008] Furthermore, the oil layer is arranged above the water layer, and the distance from the upper oil layer surface of the oil layer to the opening end surface of the oil cylinder to be tested is equal to the height of the second main body.

[0009] With the above arrangement, when the second main body slides into the oil cylinder to be tested, a space for the oil layer is formed between the second step portion of the second main body and the water layer.

[0010] Furthermore, the step S2 also includes making the end surface of the first main body part perpendicular to the axis of the oil cylinder to be tested after the axis of the gland body coincides with the axis of the oil cylinder to be tested.

[0011] The above arrangement ensures that when the gland body slides into the oil cylinder to be tested, no tilting occurs, which may cause the gland body to be unable to accurately slide into the oil cylinder to be tested.

[0012] Furthermore, the step S4 also includes that the thickness of the sealing ring squeezed on the inner side of the oil cylinder to be tested is 0.5 mm.

[0013] The above arrangement makes it easy to disassemble and assemble the gland body, and at the same time, the sealing requirement can be ensured when the gland body slides into the oil cylinder to be tested.

[0014] Furthermore, the step S6 also includes extracting high-pressure oil from the oil tank through the high-pressure pump station and injecting it into the oil layer of the oil cylinder to be tested, and providing a sealing treatment at the place where the oil pipe passes through the countersunk hole.

[0015] The above arrangement facilitates the external oil injection equipment to inject oil into the oil cylinder through the channel after being inserted into the countersunk hole, thereby ensuring that a sealed pressure test space is formed in the oil cylinder to be tested after the oil is injected.

[0016] Furthermore, the step S7 also includes setting the time T to 10 minutes. If there is water or oil leakage in the oil cylinder to be tested, the pressure test of the oil cylinder to be tested fails; if there is no water or oil leakage in the oil cylinder to be tested, the pressure test of the oil cylinder to be tested passes.

[0017] With the above settings, when there are small cracks in the oil cylinder, it takes time to observe water or oil flowing out of the cracks. Therefore, it is necessary to keep the pressure still for a period of time before observing whether water or oil flows out.

[0018] Furthermore, the step S8 also includes controlling the crane to pull the gland body upward along the axis direction of the oil cylinder so that the gland body is separated from the oil cylinder.

[0019] The above arrangement prevents the gland body from tilting during the process of separating from the oil cylinder, which causes friction between the outer side surface of the second body and the inner side surface of the oil cylinder, thereby wearing the oil cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is the front view of the present invention.

[0021] Figure 2 for Figure 1 Cross-sectional view at AA in the middle.

[0022] Figure 3 It is a schematic diagram of the present invention applied to an oil cylinder.

[0023] Figure 4 It is the work flow chart of the present invention. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] like Figures 1 to 4 As shown, a test method for detecting the pressure of a hydraulic cylinder includes a gland body, the gland body includes a first body part 1 and a second body part 2, the first body part 1 and the second body part 2 are coaxially arranged, one end of the second body part 2 is fixedly connected to the first body part 1, a first step part 11 is formed at the connection between the first body part 1 and the second body part 2, a first step surface 111 is formed on the first step part 11, the other end of the second body part 2 is protruded along the axis 3 to form a second step part 21, the diameter of the second body part 2 matches the diameter of the opening of the cylinder 4, and two or more parallel grooves 5 are provided between the first step part 1 and the second step part 2 and on the outer side surface 22 of the second body part 2, as shown in FIG. Figure 3As shown, an isolation belt 6 is provided between the grooves 5, the cross-sectional diameter range of the grooves 5 is 5-7 mm, a sealing ring 7 is installed in the groove 5, the sealing ring protrudes from the outer side surface 0.5 mm, and the clearance between the outer side surface 22 of the second main body 2 and the inner side surface 8 of the oil cylinder 4 is 0.05-0.15 mm. In this embodiment, the number of grooves 5 is set to two, the cross-sectional diameter of the groove 5 is 5 mm, the sealing ring 7 is an O-type sealing ring, the clearance between the outer side surface 22 of the second main body 2 and the inner side surface 8 of the oil cylinder 4 is 0.10 mm, and because the sealing ring 7 protrudes from the groove 5, when the gland body is sealed During the process of covering the opening of the cylinder 4, the inner side surface 8 of the cylinder 4 squeezes the sealing ring 5, so that the squeezed sealing ring 5 fills the gap between the outer side surface 22 of the second main body 2 and the inner side surface 8 of the cylinder 4. In this way, it is only necessary to apply force in the vertical direction of the pressure cover body to achieve installation and disassembly, without the need for other complex workpiece assembly and coordination, thereby meeting the sealing requirements of the cylinder 4 while also facilitating the disassembly and assembly of the pressure cover body. In this embodiment, the first main body 1 is a cylindrical structure, the second main body 2 is a cylindrical structure, and the cross-sectional area of ​​the first main body 1 is matched with the cross-sectional surface of the outer wall of the cylinder 4.

[0026] like Figure 1 As shown, the first main body 1 is provided with more than two mounting holes 12 evenly distributed around the circumference, and the mounting holes 12 are arranged through the first step surface 111 , so as to facilitate the installation of the gland body on the oil cylinder 4 by passing the screws 13 through the mounting holes 12 .

[0027] like Figure 2 As shown, the distance from the center of the mounting hole 12 to the axis 3 of the first main body 1 is greater than the distance from the outer side surface 22 to the axis 3 of the second main body 2. In this way, during the installation process, it is possible to prevent the screw 13 from contacting the outer side surface 22 after passing through the mounting hole 12 and destroying the sealing between the outer side surface 22 of the second main body 2 and the inner side surface 8 of the cylinder 4.

[0028] like Figure 2 As shown, a countersunk hole 14 is provided at the center of the first main body 1, and a channel 23 is provided at the center of the second main body 2. The channel 23 passes through the first main body 1 and the second main body 2 along the axis 3 of the second main body 2 and is connected with the countersunk hole 14. The diameter of the countersunk hole 14 is larger than the diameter of the channel 23. In this way, after the gland body is installed on the oil cylinder 4, it is convenient for external water injection equipment to be inserted into the countersunk hole 14 and then inject water into the oil cylinder 4 through the channel 23 to realize the pressure test of the oil cylinder 4.

[0029] like Figure 4 As shown, a test method for detecting the pressure of a hydraulic cylinder includes the following steps: S0 marks the height of the water layer in the oil cylinder to be tested, and then marks the height of the oil layer on the water layer, and makes the distance from the upper oil layer surface of the oil layer to the open end surface of the oil cylinder to be tested equal to the height of the second main body. In this embodiment, the height of the water layer is greater than the height of the oil layer, that is, the volume of water is greater than the volume of oil; S1 Place the oil cylinder to be tested on the test platform, and make the opening of the oil cylinder to be tested point vertically upward, and then seal the oil inlet and outlet of the oil cylinder to be tested, such as Figure 3 As shown, the oil inlet and outlet are located at the lower end of the oil cylinder (not shown in the figure), and water is injected into the oil cylinder until the water surface reaches the water layer height marked in step S0, and the water injection is stopped. Whether the water injection needs to be stopped can be determined by observation, or the volume of water that needs to be injected can be determined by determining the water layer height and then measuring a certain volume of water and stopping the water injection after it is injected.

[0030] S2 hangs the gland body on the crane, controls the crane to transport the gland body to the top of the oil cylinder to be tested, makes the axis of the gland body coincide with the axis of the oil cylinder to be tested, and ensures that the end face of the first main body is perpendicular to the axis of the oil cylinder to be tested, thereby causing the gland body to tilt and fail to accurately slide into the oil cylinder to be tested.

[0031] S3 controls the crane to vertically lower the gland body, and stops the crane operation when the second body part contacts the oil cylinder to be tested.

[0032] S4 Through the action of the self-gravity of the gland body, the second main body slides into the oil cylinder to be tested along the axis of the oil cylinder to be tested, so that the inner side surface of the oil cylinder to be tested squeezes the sealing ring set on the second main body. In this embodiment, the thickness of the sealing ring squeezed by the inner side surface of the oil cylinder to be tested is 0.5mm, so that the squeezed sealing ring fills the gap between the outer side surface of the second main body and the inner side surface of the cylinder. In another embodiment, if the self-gravity of the gland body is insufficient, a booster can be added on the crane to ensure that the gland body can smoothly enter the opening of the oil cylinder.

[0033] S5 After the second main body is completely slid into the oil cylinder to be tested, the first main body is locked with the oil cylinder to be tested by passing the fastening bolts through the mounting holes provided on the first main body; S6 calculates the volume of oil required for the oil layer according to the height of the oil layer in step S0 and the diameter of the oil cylinder. Since the oil cylinder is a column, the volume of oil required can be determined by the volume calculation formula of the column. Then, according to the calculated volume of oil, the high-pressure oil of the volume is extracted from the oil tank through the high-pressure pump station, and then the high-pressure oil is injected into the oil cylinder to be tested through the oil pipe inserted into the countersunk hole and the channel set on the first main body. In this embodiment, a sealing treatment is provided at the place where the oil pipe passes through the countersunk hole. After the high-pressure oil fills the oil layer height marked in step S0, the oil supply is stopped; S7 maintains the pressure for a period of time T. In this embodiment, the time T is set to 10 minutes. Then, the four sides, oil inlets and outlets, and welding points of the oil cylinder to be tested are detected for leakage. If there is water or oil leakage in the oil cylinder to be tested, the pressure test of the oil cylinder to be tested fails; if there is no water or oil leakage in the oil cylinder to be tested, the pressure test of the oil cylinder to be tested passes. In this embodiment, whether there is a water or oil leakage problem in the oil cylinder to be tested is determined by observation or wiping the oil cylinder.

[0034] After the pressure test, S8 extracts the oil layer in the tested cylinder, then removes the fastening bolts on the first main body, controls the crane to pull the gland body upward along the axis of the cylinder, so that the gland body is separated from the cylinder, and completes the cylinder pressure test.

[0035] The working principle of the present invention is as follows: after the oil cylinder to be tested is placed on the test platform, water is injected into the oil cylinder to be tested, and then the pressure cover body is transported to the top of the oil cylinder to be tested by a crane, and slides into the oil cylinder to be tested by the gravity of the pressure cover body itself. In this process, the inner side surface of the oil cylinder to be tested squeezes the sealing ring to fill the gap between the outer side surface of the second main body and the inner side surface of the cylinder. After the pressure cover body slides into the oil cylinder to be tested, the pressure cover body and the oil cylinder to be tested are fixed by bolts, and then high-pressure oil is injected into the oil cylinder to be tested through the countersunk hole and the channel, and after maintaining the pressure for a period of time, it is detected whether there is water or oil leakage in the oil cylinder to be tested, and then it is determined whether the oil cylinder to be tested is qualified.

Claims

1. A test method for detecting the pressure of a hydraulic cylinder, comprising connecting a gland body to the upper end surface of a hydraulic cylinder to be tested to realize the detection, wherein the gland body comprises a first body part and a second body part, wherein the cross-sectional area of ​​the second body part is smaller than the cross-sectional area of ​​the first body part, a step part is formed between the first body part and the second body part, the step part is detachably connected to the top surface of the cylinder, and there is a clearance fit between the outer side surface of the second body part and the inner side surface of the cylinder, and further comprising the following steps: S0 marks the height of the water layer in the oil cylinder to be tested, and then marks the height of the oil layer on the water layer, and the volume of the water layer is greater than the volume of the oil layer; S1: Place the oil cylinder to be tested on the test platform, and make the opening of the oil cylinder to be tested face upward vertically. Then seal the oil inlet and outlet of the oil cylinder to be tested, and inject water into the oil cylinder until the water level reaches the water layer height marked in step S0, and then stop injecting water. S2 hangs the gland body on the crane, controls the crane to transport the gland body to the top of the oil cylinder to be tested, and makes the axis of the gland body coincide with the axis of the oil cylinder to be tested; S3 controls the crane to vertically lower the gland body, and stops the crane operation when the second body part contacts the oil cylinder to be tested; S4: Under the action of the gravity of the gland body, the second body slides into the oil cylinder to be tested along the axis of the oil cylinder to be tested, so that the inner side surface of the oil cylinder to be tested squeezes the sealing ring arranged on the second body; S5 After the second main body is completely slid into the oil cylinder to be tested, the first main body is locked with the oil cylinder to be tested by passing the fastening bolts through the mounting holes provided on the first main body; S6 injects high-pressure oil into the oil cylinder to be tested through the countersunk hole and the channel provided on the first main body, and stops supplying oil after the high-pressure oil fills the oil layer height marked in step S0; S7: Maintain the pressure for a period of time T, and then check the four sides, oil inlet and outlet ports, and welding points of the tested cylinder for leakage; After the pressure test, S8 draws out the oil layer in the tested cylinder, then removes the fastening bolts on the first main body, controls the crane to lift the gland body out of the cylinder, and completes the cylinder pressure test.

2. A test method for detecting the pressure of a hydraulic cylinder according to claim 1, characterized in that: The oil layer is arranged above the water layer, and the distance from the upper oil layer surface of the oil layer to the opening end surface of the oil cylinder to be tested is equal to the height of the second main body.

3. A test method for detecting the pressure of a hydraulic cylinder according to claim 1, characterized in that: The step S2 also includes making the end surface of the first main body part perpendicular to the axis of the oil cylinder to be tested after the axis of the gland body coincides with the axis of the oil cylinder to be tested.

4. A test method for detecting the pressure of a hydraulic cylinder according to claim 1, characterized in that: The step S4 also includes that the thickness of the sealing ring squeezed on the inner side of the oil cylinder to be tested is 0.5 mm.

5. A test method for detecting the pressure of a hydraulic cylinder according to claim 1, characterized in that: The step S6 also includes extracting high-pressure oil from the oil tank through the high-pressure pump station and injecting it into the oil layer of the oil cylinder to be tested, and providing a sealing treatment at the place where the oil pipe passes through the countersunk hole.

6. A test method for detecting the pressure of a hydraulic cylinder according to claim 1, characterized in that: The step S7 also includes setting the time T to 10 minutes. If there is water or oil leakage in the oil cylinder to be tested, the pressure test of the oil cylinder to be tested fails; if there is no water or oil leakage in the oil cylinder to be tested, the pressure test of the oil cylinder to be tested passes.

7. A test method for detecting the pressure of a hydraulic cylinder according to claim 1, characterized in that: The step S8 also includes controlling the crane to pull the gland body upward along the axis direction of the oil cylinder so that the gland body is separated from the oil cylinder.

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