A hydraulic cylinder seal detection device

Abstract

This utility model discloses a hydraulic cylinder sealing performance testing device, relating to the technical field of hydraulic cylinder sealing testing equipment. It includes: a housing; a testing cylinder and a reference cylinder, both of identical size and housed within the housing; and a differential pressure detection component and a pressurization component located on the upper and lower sides of one side of the housing. The differential pressure detection component includes a base, a differential pressure sensor mounted on the base, and two connecting pipes connected to the input end of the differential pressure sensor respectively to the testing cylinder and the reference cylinder. An output wire is connected to a display mounted on the base. This utility model, through a comparative design of the "test cylinder - reference cylinder," utilizes the relative relationship between pressure changes and leakage levels from the differential pressure sensor to achieve accurate detection of the cylinder's sealing performance, exhibiting particularly high sensitivity to minute leaks.

Description

Technical Field

[0001] This utility model relates to the technical field of hydraulic cylinder sealing testing equipment, specifically a hydraulic cylinder sealing testing device. Background Technology

[0002] A hydraulic cylinder is a hydraulic actuator that converts hydraulic energy into mechanical energy to perform linear reciprocating motion (or oscillating motion). When used to achieve reciprocating motion, it eliminates the need for a speed reduction device, eliminates transmission backlash, and provides smooth movement. Therefore, it is widely used in the hydraulic systems of various machines. However, hydraulic cylinders must undergo airtightness testing before leaving the factory to prevent air or oil leaks after sale.

[0003] Existing methods for testing the air tightness of hydraulic cylinders often involve observing bubbles emerging from water at the leak location. This method has some drawbacks:

[0004] First, it is rather subjective and requires careful observation, which is rather troublesome and inefficient;

[0005] Secondly, for minor leaks, the leakage is easily overlooked, resulting in a large detection error;

[0006] Therefore, a hydraulic cylinder sealing performance testing device is proposed. Utility Model Content

[0007] The purpose of this invention is to provide a hydraulic cylinder sealing performance testing device. This device uses a comparative design of "test cylinder - reference cylinder" and the relative relationship between pressure change and leakage degree of differential pressure sensor to achieve accurate detection of cylinder sealing performance, especially with high sensitivity to minute leaks.

[0008] To achieve the above objectives, this utility model provides the following technical solution: a hydraulic cylinder sealing performance testing device, comprising: a housing; a testing cylinder and a reference cylinder of the same volume disposed within the housing; and a differential pressure detection component and a pressurizing component disposed on one side of the housing, wherein the differential pressure detection component includes a base, a differential pressure sensor disposed on the base, and two connecting pipes connected to the input end of the differential pressure sensor are respectively connected to the testing cylinder and the reference cylinder, and an electrical wire disposed at its output end is connected to a display disposed on the base; the pressurizing component can be connected to the testing cylinder and the reference cylinder and is used to inject gas at the same pressure into both to maintain initial differential pressure balance.

[0009] Preferably, the detection cylinder body includes a first U-shaped frame built into the chassis, a hydraulic cylinder to be tested assembled in the middle of the first U-shaped frame, and a first connecting cylinder and a push rod clamping assembly disposed on both sides of the first U-shaped frame and clamping both sides of the hydraulic cylinder to be tested. The side wall of the first connecting cylinder is connected to its corresponding connecting pipe, and its end away from the hydraulic cylinder to be tested is connected to the pressurizing assembly. The push rod clamping assembly is used for laterally pressing the hydraulic cylinder to be tested and the first connecting cylinder together.

[0010] Preferably, the push rod clamping assembly includes a push plate slidably mounted inside the first U-shaped frame and directly abutting against the hydraulic cylinder to be tested; and a plurality of first electric push rods disposed on the outside of the chassis, wherein the telescopic end of each first electric push rod passes through a third through hole opened in the side wall of the chassis and is fixed with a push rod body, and the end of each push rod body away from the first electric push rod is fixed to the push plate. When the first electric push rod is running, the plurality of push rod bodies can indirectly abut against the hydraulic cylinder to be tested by pushing the push plate; and also includes a clamping member disposed on the push plate for longitudinal clamping of the hydraulic cylinder to be tested.

[0011] Preferably, the clamping member includes a rectangular frame fixed to the push plate near the push rod body, a mounting hole opened at the top of the rectangular frame; and a screw rotatably installed inside the mounting hole, with a handle fixed at one end of the screw and a threaded sleeve threaded onto the other end of the screw extending into the rectangular frame; and a pressure block fixed to the threaded sleeve and abutting against the top of the hydraulic cylinder to be tested.

[0012] Preferably, the reference cylinder includes a second U-shaped frame built into the chassis and a piston cylinder fixed to the second U-shaped frame. The piston cylinder has a second connecting cylinder sealed and connected to one side, and a piston rod body is provided on the other side for adjusting the internal space of the piston cylinder. The side wall of the second connecting cylinder is connected to its corresponding connecting pipe, and its end away from the piston cylinder is connected to the pressurization component.

[0013] Preferably, the piston rod body includes a piston plate disposed inside the piston cylinder, wherein a piston rod is fixed on the side of the piston plate away from the second connecting cylinder, the piston rod passes through a second through hole opened on the piston cylinder and extends outward for a certain distance; and a second electric push rod disposed on the outside of the chassis, wherein the telescopic end of the second electric push rod passes through a first through hole opened on the side wall of the chassis and is fixed to the end of the piston rod away from the piston plate.

[0014] Preferably, a second sealing ring and a first sealing ring are respectively provided on the side of the second connecting cylinder near the piston cylinder and the side of the first connecting cylinder near the hydraulic cylinder to be tested.

[0015] Preferably, the pressurization assembly includes a pressure regulating device built into the base and two connecting pipes disposed at the output end of the pressure regulating device, wherein the ends of the two connecting pipes away from the pressure regulating device pass through through slots opened in the side wall of the base and the chassis, respectively, and are sealed and connected to the second connecting cylinder and the first connecting cylinder.

[0016] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0017] This invention employs a differential pressure method to construct a closed comparison device. This involves connecting the detection cylinder and the reference cylinder, and using a differential pressure detection component connected between them to form a closed loop of a "sealed cavity-reference cavity." The reference cylinder's volume can be adjusted to match the detection cylinder's volume. To ensure the initial pressure difference is the same, a pressurizing component simultaneously fills both the detection and reference cylinders with gas at the same pressure. At this point, the pressures in both cylinders are equal, establishing an initial pressure difference balance. After the pressurizing component stops filling, if there is a leak in the detection cylinder, the pressure inside the connecting pipe will decrease due to gas loss. The reference cylinder, having no leak (or negligible leakage), maintains a stable pressure. The pressure difference between the two cylinders gradually increases over time. The value displayed on the monitor of the differential pressure detection component reflects any minor leaks in the detection cylinder. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural diagram of the present invention in its working state;

[0019] Figure 2 for Figure 1 A top-view structural diagram;

[0020] Figure 3 for Figure 1 A schematic diagram of the side view structure;

[0021] Figure 4 This is a schematic diagram of the structure of this utility model;

[0022] Figure 5 This is a magnified structural diagram of point A;

[0023] Figure 6 for Figure 4 Another perspective of the three-dimensional structure diagram;

[0024] Figure 7 This is an enlarged structural diagram of a partial disassembly of the cylinder block for reference.

[0025] Figure 8 This is an enlarged structural schematic diagram of the cylinder to be tested.

[0026] In the diagram: 111, chassis; 211, second U-shaped frame; 212, piston cylinder; 213, piston plate; 214, piston rod; 215, second electric push rod; 216, second connecting cylinder; 217, second sealing ring; 311, first U-shaped frame; 312, hydraulic cylinder to be tested; 313, push plate; 314, push rod body; 315, first electric push rod; 316, first connecting cylinder; 317, first sealing ring; 318, rectangular frame; 319, screw; 320, screw sleeve; 321, handle; 322, pressure block; 411, base; 412, pressure regulating device; 413, connecting pipe; 414, display; 415, differential pressure sensor; 416, connecting pipe; 417, wire. Detailed Implementation

[0027] In the description of this utility model, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. The various embodiments of this utility model are described in detail below with reference to the accompanying drawings. Example 1

[0028] Please see Figures 1 to 8 The present invention preferably provides the following technical solution: a hydraulic cylinder sealing performance testing device, comprising: a housing 111; a testing cylinder and a reference cylinder of the same volume disposed within the housing 111; and a differential pressure detection component and a pressurizing component disposed on one side of the housing 111. The differential pressure detection component includes a base 411 and a differential pressure sensor 415 disposed on the base 411. Two connecting pipes 416 connected to the input end of the differential pressure sensor 415 are respectively connected to the testing cylinder and the reference cylinder, and a wire 417 disposed at its output end is connected to a display 414 disposed on the base 411. The pressurizing component can be connected to the testing cylinder and the reference cylinder and is used to inject gas at the same pressure into both cylinders to maintain initial differential pressure balance.

[0029] It is known that existing hydraulic cylinder sealing chambers (such as the gap between the piston and cylinder barrel, and the gap between the piston rod and guide sleeve) will leak air and depressurize after pressurization if there is a sealing failure (such as excessive gap or damaged seal). Therefore, this application uses a differential pressure method to construct a closed comparison device, that is, connecting the test cylinder and the reference cylinder. Figure 1 , 2As shown in Figures 3 and 4, the pressure difference detection component connecting the two cylinders forms a closed loop of "sealed cavity-reference cavity". The reference cylinder can be adjusted according to the volume of the detection cylinder to make the volumes of the two cylinders the same. In order to ensure that the initial pressure difference between the two cylinders is the same, the pressurization component of this device can simultaneously fill the detection cylinder and the reference cylinder with the same pressure of gas. At this time, the pressure of the two cylinders is equal to establish the initial pressure difference balance.

[0030] After the pressurization component stops inflating, the differential pressure sensor 415, where the differential pressure detection component is located, has two connecting pipes 416 connected to its input end, which are respectively connected to the detection cylinder and the reference cylinder. Its output end is connected to the display 414 set on the base 411. Therefore, if there is a leak in the detection cylinder, the internal pressure of the connecting pipe 416 connected to the detection cylinder will drop due to gas loss. Since there is no leak in the reference cylinder (or the leak is negligible), the pressure remains stable. The pressure difference between the two gradually increases over time. At this time, the value displayed on the display 414 where the differential pressure detection component is located can reflect the slight leak in the detection cylinder.

[0031] It is worth noting that the differential pressure sensor 415 here is a mature existing technology. It measures the difference between two pressure points, converts the deformation of the sensitive element (such as diaphragm bending) into an electrical signal, and then outputs a standard signal after circuit processing. The signal is then displayed in real time through the existing display 414. Here, the differential pressure sensor 41 is preferably a diffused silicon piezoresistive or silicon micromechanical sensor, which has fast response and good linearity. It is selected with an accuracy of 0.1 Pa to achieve high-precision detection of minute leaks. Example 2

[0032] In another embodiment of this utility model, the detection cylinder body includes a first U-shaped frame 311 built into the housing 111, a hydraulic cylinder 312 to be tested assembled in the middle of the first U-shaped frame 311, and a first connecting cylinder 316 disposed on both sides of the first U-shaped frame 311 and clamped on both sides of the hydraulic cylinder 312 to be tested, and a push rod clamping assembly. The sidewall of the first connecting cylinder 316 is connected to its corresponding connecting pipe 416, and its end away from the hydraulic cylinder 312 to be tested is connected to a pressurizing assembly. The push rod clamping assembly is used for laterally pressing the hydraulic cylinder 312 to be tested against the first connecting cylinder 316. Further, the push rod clamping assembly includes components slidably mounted on the first U-shaped frame. The system includes a push plate 313 inside the housing 111 that directly contacts the hydraulic cylinder 312 to be tested; and a plurality of first electric push rods 315 disposed on the outside of the housing 111, wherein the telescopic end of each first electric push rod 315 passes through a third through hole opened in the side wall of the housing 111 and is fixed with a push rod body 314, and one end of each push rod body 314 away from the first electric push rod 315 is fixed to the push plate 313. When the first electric push rod 315 is running, the plurality of push rod bodies 314 can indirectly press against the hydraulic cylinder 312 to be tested by pushing the push plate 313; and also includes a clamping member disposed on the push plate 313 for longitudinal clamping of the hydraulic cylinder 312 to be tested.

[0033] In this embodiment, the hydraulic cylinder 312 to be tested can be assembled in the middle of the first U-shaped frame 311, while the first connecting cylinder 316 and the push rod clamping assembly are distributed on both sides of the first U-shaped frame 311 and can clamp both sides of the hydraulic cylinder 312 to be tested. The inner cavity of the hydraulic cylinder 312 to be tested is connected to the first connecting cylinder 316 on one side and closed on the other side.

[0034] like Figure 1 , 2 As shown in Figures 5, 6, and 8, when the hydraulic cylinder 312 to be tested needs to be assembled, in the initial state, the push plate 313 is far away from the first connecting cylinder 316. When the hydraulic cylinder 312 to be tested is placed between the push plate 313 and the first connecting cylinder 316, with the operation of the second electric push rod 215, several push rod bodies 314 can push the hydraulic cylinder 312 to be tested towards the first connecting cylinder 316 and seal it with the first connecting cylinder 316 in order to realize the connection between the hydraulic cylinder 312 to be tested and its corresponding connecting pipe 416. When the pressurizing component pressurizes the hydraulic cylinder 312 to be tested through the first connecting cylinder 316, the gas can enter the interior of the connecting pipe 416. If the differential pressure sensor 415 shows a value difference, it indicates that there is a leakage in the hydraulic cylinder 312 to be tested.

[0035] Furthermore, the clamping component includes a rectangular frame 318 fixed to the side of the push plate 313 near the push rod body 314, a mounting hole opened on the top of the rectangular frame 318; and a screw 319 rotatably installed inside the mounting hole, with a handle 321 fixed to one end of the screw 319 and the other end extending into the rectangular frame 318 and threaded with a screw sleeve 320; it also includes a pressure block 322 fixed to the screw sleeve 320 and abutting against the top of the hydraulic cylinder 312 to be tested.

[0036] like Figure 5 As shown, in order to improve the stability of the hydraulic cylinder 312 under test, the clamping member provided in this application, the pressure block 322 where it is located can be pressed against or moved away from the top of the hydraulic cylinder 312 under test by the longitudinal movement of the screw sleeve 320, and cooperate with the first U-shaped frame 311 to achieve longitudinal clamping or release of the hydraulic cylinder 312 under test. Example 2

[0037] In another embodiment of this utility model, the reference cylinder includes a second U-shaped frame 211 built into the housing 111, and a piston cylinder 212 fixed to the second U-shaped frame 211. A second connecting cylinder 216 is sealed to one side of the piston cylinder 212, and a piston rod is provided on the other side for adjusting the internal space of the piston cylinder 212. The side wall of the second connecting cylinder 216 is connected to its corresponding connecting pipe 416, and its end away from the piston cylinder 212 is connected to a pressurizing component. Further, the piston rod includes a piston plate 213 internally disposed in the piston cylinder 212. A piston rod 214 is fixed to the side of the piston plate 213 away from the second connecting cylinder 216. The piston rod 214 passes through a second through hole opened on the piston cylinder 212 and extends outward for a distance. A second electric push rod 215 is disposed outside the housing 111, and the telescopic end of the second electric push rod 215 passes through a first through hole opened on the side wall of the housing 111 and is fixed to the end of the piston rod 214 away from the piston plate 213.

[0038] like Figure 1 , 2 As shown in Figures 6 and 7, the piston cylinder 212 is fixed in the middle of the second U-shaped frame 211, while the second connecting cylinder 216 connected on one side is connected to its corresponding connecting pipe 416, and a piston plate 213 is provided on the other side, as shown in Figures 7 and 8. Figure 7 The piston rod 214, which is fixed to the side wall of the piston plate 213, extends outward and is connected to the telescopic end of the second electric push rod 215.

[0039] Therefore, when it is necessary to adjust the volume of the reference cylinder and the hydraulic cylinder 312 to be tested, a standard hydraulic cylinder of the same model as the hydraulic cylinder 312 to be tested is first prepared. At this time, under the action of the differential pressure sensor 415, when the pressurizing component fills the standard hydraulic cylinder and the piston cylinder 212 with the same volume of gas, the second electric push rod 215 can drive the piston rod 214 and the piston plate 213 to move adaptively until the air pressure inside the piston cylinder 212 is consistent with the air pressure of the standard hydraulic cylinder, that is, when the differential pressure sensor 415 displays a value of 0, at this time the gap between the piston plate 213 and the piston cylinder 212 is consistent with the cavity of the standard hydraulic cylinder, so as to complete the adjustment of the reference cylinder volume.

[0040] Subsequently, during the airtightness test of the hydraulic cylinder 312 under test, the hydraulic cylinder 312 under test is first installed. The pressurizing component simultaneously adds the same volume of gas into the piston cylinder 212 and the hydraulic cylinder 312 under test. If the hydraulic cylinder 312 under test has a leak, the internal pressure of the connecting pipe 416 connected to the hydraulic cylinder 312 under test will decrease due to gas loss. Since the reference cylinder has no leak or the leak is negligible, the pressure remains stable, and the differential pressure sensor 415 will display a pressure difference value. As time goes on, the pressure difference value increases to reflect that the hydraulic cylinder 312 under test has a leak. Conversely, if the differential pressure sensor 415 is 0, it indicates that the hydraulic cylinder 312 under test has no leak.

[0041] Furthermore, a second sealing ring 217 and a first sealing ring 317 are respectively provided on the side of the second connecting cylinder 216 near the piston cylinder 212 and the side of the first connecting cylinder 316 near the hydraulic cylinder 312 to be tested, such as... Figure 1 , 2 As shown, the sealing performance between the second connecting cylinder 216 and the piston cylinder 212, and between the first connecting cylinder 316 and the hydraulic cylinder 312 to be tested is further improved.

[0042] Furthermore, the pressurization assembly includes a pressure regulating device 412 internally disposed in the base 411, and two connecting pipes 413 disposed at the output end of the pressure regulating device 412. The ends of the two connecting pipes 413 away from the pressure regulating device 412 pass through through slots opened in the side walls of the base 411 and the housing 111, respectively, and are sealed and connected to the second connecting cylinder 216 and the first connecting cylinder 316.

[0043] It is worth noting that, for example Figure 3 As shown, the pressure regulating device 412 here is a mature existing technology. When it is working, by adjusting the operating parameters, it can simultaneously supply air pressure to the inside of the second connecting cylinder 216 and the first connecting cylinder 316, and set the pressure values ​​of the detection cylinder and the reference cylinder to be the same.

[0044] In this utility model, unless otherwise explicitly specified and limited, the terms "installation", "connection", "fixation" and other terms should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral part. There are various ways to install detachably, such as by using a plug-in and snap-fit ​​method, or by using a bolt connection, etc.

[0045] The above description of the specific embodiments of this utility model is only used to further illustrate this utility model and should not be construed as limiting the scope of protection of this utility model. Any non-essential improvements and adjustments made to this utility model by technical engineers based on the above description of the utility model shall fall within the scope of protection of this utility model.

Claims

1. A hydraulic cylinder sealing performance testing device, characterized in that... ,include: Chassis (111); The detection cylinder and reference cylinder are installed in the chassis (111) and have the same volume; And differential pressure detection components and pressurization components located on the upper and lower sides of one side of the chassis (111); The differential pressure detection component includes a base (411), a differential pressure sensor (415) mounted on the base (411), and two connecting pipes (416) connected to the input end of the differential pressure sensor (415) are respectively connected to the detection cylinder and the reference cylinder, and the wire (417) mounted on its output end is connected to the display (414) mounted on the base (411). The pressurization component can be connected to the detection cylinder and the reference cylinder and used to inject gas at the same pressure into both to maintain the initial pressure difference balance.

2. The hydraulic cylinder sealing performance testing device according to claim 1, characterized in that: The detection cylinder body includes a first U-shaped frame (311) built into the chassis (111), and a hydraulic cylinder (312) to be tested assembled in the middle of the first U-shaped frame (311). And a first connecting cylinder (316) and a push rod clamping assembly disposed on both sides of the first U-shaped frame (311) and clamped on both sides of the hydraulic cylinder (312) to be tested, wherein the side wall of the first connecting cylinder (316) is connected to its corresponding connecting pipe (416), and its end away from the hydraulic cylinder (312) to be tested is connected to the pressurizing assembly. The push rod clamping assembly is used for lateral clamping of the hydraulic cylinder (312) to be tested and the first connecting cylinder (316).

3. The hydraulic cylinder sealing performance testing device according to claim 2, characterized in that: The push rod clamping assembly includes a push plate (313) that is slidably installed inside the first U-shaped frame (311) and directly abuts against the hydraulic cylinder (312) to be tested. And a plurality of first electric push rods (315) are provided on the outside of the chassis (111), wherein the telescopic end of each first electric push rod (315) passes through a third through hole opened in the side wall of the chassis (111) and is fixed with a push rod body (314), and one end of each push rod body (314) away from the first electric push rod (315) is fixed to a push plate (313). When the first electric push rod (315) is running, the plurality of push rod bodies (314) can indirectly press against the hydraulic cylinder (312) to be tested by pushing the push plate (313). It also includes a clamping member disposed on the push plate (313) for longitudinal clamping of the hydraulic cylinder (312) to be tested.

4. The hydraulic cylinder sealing performance testing device according to claim 3, characterized in that: The clamping member includes a rectangular frame (318) fixed to the side of the push plate (313) near the push rod body (314), and a mounting hole opened on the top of the rectangular frame (318); And a screw (319) is rotatably installed inside the mounting hole, and one end of the screw (319) is fixed with a handle (321), and the other end extends into the rectangular frame (318) and is threaded with a screw sleeve (320). It also includes a pressure block (322) fixed to the threaded sleeve (320) and in contact with the top of the hydraulic cylinder (312) to be tested.

5. The hydraulic cylinder sealing performance testing device according to claim 4, characterized in that: The reference cylinder body includes a second U-shaped frame (211) built into the chassis (111) and a piston cylinder (212) fixed to the second U-shaped frame (211). The piston cylinder (212) has a second connecting cylinder (216) sealed and connected to one side, and a piston rod body is provided on the other side for adjusting the internal space of the piston cylinder (212). The side wall of the second connecting cylinder (216) is connected to its corresponding connecting pipe (416), and the end of the connecting cylinder (216) away from the piston cylinder (212) is connected to the pressurization assembly.

6. The hydraulic cylinder sealing performance testing device according to claim 5, characterized in that: The piston rod body includes a piston plate (213) disposed inside the piston cylinder (212), wherein a piston rod (214) is fixed on the side of the piston plate (213) away from the second connecting cylinder (216), and the piston rod (214) passes through the second through hole opened on the piston cylinder (212) and extends outward for a distance; And a second electric push rod (215) is provided on the outside of the chassis (111), and the telescopic end of the second electric push rod (215) passes through the first through hole opened in the side wall of the chassis (111) and is fixed to one end of the piston rod (214) away from the piston plate (213).

7. The hydraulic cylinder sealing performance testing device according to claim 5, characterized in that: The second connecting cylinder (216) near the piston cylinder (212) and the first connecting cylinder (316) near the hydraulic cylinder (312) to be tested are respectively provided with a second sealing ring (217) and a first sealing ring (317).

8. The hydraulic cylinder sealing performance testing device according to claim 1, characterized in that: The pressurization assembly includes a pressure regulating device (412) internally disposed in the base (411) and two connecting pipes (413) disposed at the output end of the pressure regulating device (412). The ends of the two connecting pipes (413) away from the pressure regulating device (412) pass through through slots opened in the side wall of the base (411) and the chassis (111) respectively and are sealed and connected to the second connecting cylinder (216) and the first connecting cylinder (316).

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