A light transmittance detection device for agricultural film production

Abstract

The present invention relates to the technical field of transmittance detection devices, and in particular to a transmittance detection device for agricultural film production. It comprises: a detection host; a detection probe, fixedly connected to the upper side of the detection host through a column, guide rails are installed on both sides of the detection host, the guide rails are slidably connected to electric sliders, and the electric sliders are rotatably connected to rollers; an electric push rod, fixed to the column of the detection host, the extrusion assembly is installed with fixed slide rails, and slide grooves are provided on both sides of the fixed slide rails, and the fixed slide rails are located above the guide rails; there are two sliding members, and the two sliding members are respectively slidably connected to the slide grooves of the fixed slide rails, and the sliding members are rotatably connected to extrusion rollers. The present invention utilizes two groups of rollers and extrusion rollers to squeeze each other to flatten the film to the left and right sides, thereby reducing the degree of bending of the film and weakening the influence of the creases of the film on its transmittance.

Description

Technical Field

[0001] The present invention relates to the technical field of light transmittance detection devices, and in particular to a light transmittance detection device for agricultural film production. Background Art

[0002] Agricultural film, also known as agricultural film, has a light transmittance test that is an important step in ensuring its effective use in agricultural production. Light transmittance directly affects plant photosynthesis and growth and development, so it requires precise measurement and control.

[0003] When conducting transmittance testing on agricultural film, a batch of agricultural film samples need to be prepared in advance. The flatness and cleanliness of the agricultural film samples need to be ensured during testing. Since the agricultural film samples themselves are elastic, local parts of the agricultural film samples will bend or even crease during testing. The bending of the agricultural film samples will cause uneven thickness distribution on the surface of the agricultural film, resulting in differences in transmittance in different areas, which will affect the measurement of the overall transmittance and make the results unable to reflect the true performance of the agricultural film. In addition, different agricultural film samples need to be tested multiple times during testing. The testers keep stretching the samples, which will greatly reduce the efficiency of the agricultural film sample testing. Summary of the Invention

[0004] In order to overcome the shortcoming that the existing transmittance detection device cannot flatten the agricultural film sample, the present invention provides a transmittance detection device for agricultural film production.

[0005] Technical solution: A light transmittance detection device for agricultural film production, including:

[0006] Detect host;

[0007] The detection probe is fixed to the upper side of the detection host through a column. Guide rails are installed on both sides of the detection host. The guide rails are slidably connected to electric sliders, and the electric sliders are rotatably connected to rollers.

[0008] An electric push rod is fixedly connected to the column of the detection host. The telescopic end of the electric push rod is provided with a squeezing assembly, which is used to pre-fix the agricultural film sample. The squeezing assembly is installed with a fixed slide rail, and slide grooves are provided on both sides of the fixed slide rail. The fixed slide rail is located above the guide rail.

[0009] Two sliding members are provided, and the two sliding members are respectively slidably connected to the slide grooves of the fixed slide rails. The sliding members are rotatably connected to the squeezing rollers. The side of the sliding member away from the squeezing rollers is fixedly connected to a connecting shell. The side of the connecting shell close to the electric slider is fixedly connected to a sliding rod. The sliding rod passes through the adjacent electric sliders and the two are slidably connected.

[0010] The squeezing roller and the adjacent supporting rollers clamp the agricultural film and stretch it to both sides, so that the agricultural film is flattened on the upper side of the detection host.

[0011] Furthermore, the squeezing roller is located directly above the supporting roller and is used to apply vertical squeezing force to the agricultural film sample.

[0012] Furthermore, the upper side of the roller is flush with the upper side of the detection host, so that the agricultural film sample is always in contact with the upper side of the detection host when being stretched.

[0013] Furthermore, the outer sides of the supporting roller and the squeezing roller are wrapped with anti-slip sleeves for increasing the friction between the supporting roller, the squeezing roller and the agricultural film sample.

[0014] Furthermore, the extrusion assembly includes:

[0015] A fixed housing is fixedly connected to the telescopic end of the electric push rod, and the fixed housing is slidably connected to a sliding column, and the sliding column passes through the fixed slide rail and the two are fixedly connected;

[0016] a spring, sleeved on the outside of the sliding column, with two ends of the spring respectively fixed to the fixed housing and the fixed slide rail;

[0017] The extrusion block is fixedly connected to the lower end of the sliding column and is used for pre-fixing the agricultural film sample.

[0018] Furthermore, the lower side of the extrusion block is set to a smooth material to reduce the friction resistance between the extrusion block and the agricultural film sample.

[0019] Furthermore, the lower side of the squeezing block is flush with the lower side of the squeezing roller.

[0020] Furthermore, it also includes:

[0021] Two sets of resistance adjustment mechanisms, each of which is provided between the sliding member and the adjacent connecting shell, and includes:

[0022] a first connecting block, the first connecting block being fixedly connected to one end of the squeezing roller close to the connecting shell, the first connecting block being located in the connecting shell, and a connecting rod being spline-connected to a side of the connecting shell away from the squeezing roller;

[0023] a second connecting block, fixedly connected to one end of the connecting rod close to the first connecting block and located in the connecting shell, wherein the connecting rod is provided with threads;

[0024] A fixing frame is fixedly connected to a side of the connecting shell away from the sliding member, the fixing frame is rotatably connected to a threaded sleeve, and the threaded sleeve is threadedly connected to the thread of the connecting rod;

[0025] A fixed rod is fixedly connected to one side of the threaded sleeve, the sliding member is hinged to a hydraulic rod through a mounting seat, the telescopic end of the hydraulic rod is hinged to the fixed rod, two elastic oil bags are fixedly connected between the fixed shell and the sliding column, and the elastic oil bags are filled with hydraulic oil, and the hydraulic rod and the elastic oil bag are connected through an oil guide pipe.

[0026] Furthermore, the first connecting block and the second connecting block are both composed of magnets distributed at intervals, and a gap is left between the first connecting block and the second connecting block.

[0027] Furthermore, the cross-sectional area of ​​the elastic oil bag is larger than the cross-sectional area of ​​the hydraulic rod oil chamber.

[0028] Compared with the prior art, the present invention has the following advantages: 1. The present invention utilizes two sets of rollers and squeezing rollers to squeeze each other and flatten the film to the left and right sides, thereby reducing the degree of bending of the film and weakening the influence of the creases of the film on its transmittance, thereby improving the accuracy of the device in detecting the transmittance of the film and reducing the labor intensity of the inspectors.

[0029] 2. The present invention utilizes the second connecting block to generate resistance to the adjacent first connecting block, thereby providing resistance for the rotation of the extrusion roller. When the supporting roller and the extrusion roller move synchronously, both the supporting roller and the extrusion roller rotate, and the film is flattened by the friction force of the extrusion roller on the film. In addition, the magnetic field between the first connecting block and the second connecting block is utilized to ensure that the resistance encountered by the extrusion roller during rotation remains the same.

[0030] 3. The present invention utilizes a thread to drive adjacent connecting rods to slide along the connecting shell, and the connecting rod drives the second connecting block to move closer to the first connecting block, thereby reducing the gap between the first connecting block and the second connecting block, and increasing the magnetic field strength between the first connecting block and the second connecting block, thereby increasing the thickness of the film. The magnetic field strength between the first connecting block and the second connecting block increases, and the resistance of the extrusion roller during rotation increases, thereby increasing the pulling force on the film to both sides, so that the film is in a flattened state on the upper side of the detection host, reducing the influence of creases on the detection accuracy of the film transmittance. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0032] Figure 2 This is a schematic diagram of the three-dimensional structure of the fixed slide rail, extrusion block and other parts of the present invention;

[0033] Figure 3 A schematic diagram of the three-dimensional structure of the present invention from another perspective;

[0034] Figure 4 It is a schematic diagram of the three-dimensional structure of the parts such as the supporting roller and the squeezing roller of the present invention;

[0035] Figure 5 It is a schematic diagram of the three-dimensional structure of the electric push rod and the fixed housing and other parts of the present invention;

[0036] Figure 6 It is a schematic diagram of the cross-sectional three-dimensional structure of the fixed shell of the present invention;

[0037] Figure 7 It is a schematic diagram of the cross-sectional three-dimensional structure of the connecting shell of the present invention;

[0038] Figure 8 It is a rear perspective structural diagram of the threaded sleeve, hydraulic rod and other parts of the present invention.

[0039] Figure numerals: 1. Detection host, 2. Detection probe, 3. Guide rail, 4. Electric slider, 5. Roller, 6. Electric push rod, 7. Fixed slide rail, 8. Sliding member, 9. Extrusion roller, 10. Connecting shell, 11. Slide rod, 12. Fixed shell, 13. Sliding column, 14. Spring, 15. Extrusion block, 16. First connecting block, 17. Connecting rod, 18. Second connecting block, 19. Fixed frame, 20. Threaded sleeve, 21. Fixed rod, 22. Hydraulic rod. DETAILED DESCRIPTION

[0040] Although the present invention may be described with respect to a particular application or industry, those skilled in the art will recognize the broader applicability of the present invention.Any numerical designations such as first or second are merely exemplary and are not intended to limit the scope of the present invention in any way.

[0041] Example 1: A light transmittance detection device for agricultural film production, referring to Figure 1-Figure 5, including: a detection host 1; a detection probe 2, which is fixed to the upper side of the detection host 1 through a column, the detection probe 2 is perpendicular to the detection host 1, and guide rails 3 are installed on both sides of the detection host 1, the guide rails 3 are slidably connected to the electric slider 4, and the electric slider 4 is rotatably connected to the roller 5. The guide rails 3 and the electric slider 4 are existing devices, and their internal structures are not shown in the accompanying drawings; an electric push rod 6, which is fixed to the column of the detection host 1, and an extrusion assembly is provided at the telescopic end of the electric push rod 6, and the extrusion assembly is equipped with a fixed slide rail 7, and a slide groove is provided on both sides of the fixed slide rail 7. The slide groove cross section of the fixed slide rail 7 is set to T-shaped, and the fixed slide rail 7 is located above the guide rail 3; there are two sliding members 8, and the two sliding members 8 are respectively slidably connected to the slide groove of the fixed slide rail 7, and the sliding member 8 is rotatably connected to the extrusion roller 9, and the rear of the sliding member 8 The side is fixed with a connecting shell 10, and the lower side of the connecting shell 10 is fixed with a sliding rod 11. The sliding rod 11 passes through the adjacent electric slider 4 and the two are slidably connected. The electric slider 4 uses the sliding rod 11 to drive the adjacent sliding parts 8 to move synchronously; the squeezing roller 9 and the adjacent rollers 5 clamp the agricultural film and stretch it to both sides, so that the agricultural film is flattened on the upper side of the detection host 1, reducing the influence of the bending of the agricultural film sample on the transmittance detection. The squeezing roller 9 is located directly above the roller 5 and is used to apply vertical squeezing force to the agricultural film sample, reduce the deformation of the agricultural film sample when it is tightened, and flatten the agricultural film sample laterally. The upper side of the roller 5 is flush with the upper side of the detection host 1, keeping the agricultural film sample in contact with the upper side of the detection host 1 when it is stretched. The outer sides of the roller 5 and the squeezing roller 9 are wrapped with anti-slip sleeves to increase the friction between the roller 5 and the squeezing roller 9 and the agricultural film sample.

[0042] Reference Figure 5 and Figure 6 The extrusion assembly includes: a fixed shell 12, fixed to the telescopic end of the electric push rod 6, the fixed shell 12 is slidably connected to a sliding column 13, the sliding column 13 passes through the fixed slide rail 7 and the two are fixedly connected; a spring 14 is sleeved on the outside of the sliding column 13, and the two ends of the spring 14 are respectively fixed to the fixed shell 12 and the fixed slide rail 7; an extrusion block 15 is fixed to the lower end of the sliding column 13, and is used to pre-fix the agricultural film sample. The lower side of the extrusion block 15 is set to a smooth material to reduce the friction resistance between the extrusion block 15 and the agricultural film sample. The lower side of the extrusion block 15 is flush with the lower side of the extrusion roller 9 to ensure that the extrusion roller 9 and the extrusion block 15 contact the agricultural film sample together.

[0043] In the above scheme, the purpose is to increase the flatness of the agricultural film sample, reduce the influence of the creases on the agricultural film sample on its transmittance, and improve the accuracy of the detection of agricultural film samples by this device. In order to ensure the stability of the detection host 1, four adjustment legs can be installed on the lower side of the detection host 1. A light source for detection in cooperation with the detection probe 2 is provided on the upper side of the detection host 1. The light generated by the light source on the detection host 1 passes through the agricultural film sample and is detected by the detection probe 2. In order to improve the detection efficiency of the agricultural film, the illumination range of the light source on the upper side of the detection host 1 can be increased, and the detection probe 2 can be set to be movable to perform multi-point detection on the agricultural film sample to measure the transmittance of the agricultural film sample. The left and right guide rails 3 are on the same straight line, and the two electric sliders 4 are of the same model, which ensures that the two electric sliders 4 move at the same speed. A control panel is installed on the front side of the detection host 1. The control panel is electrically connected to the two electric sliders 4 for controlling the movement of the electric sliders 4 along adjacent guide rails 3. The electric push rod 6 is also electrically connected to the control panel of the detection host 1.

[0044] Workflow: When using this device to test agricultural film samples (hereinafter referred to as "film"), the tester places the film on the upper side of the test host 1, and the film is bent downward on the upper side of the two rollers 5 (such as Figure 1 ), the inspection personnel correct the placement of the film and start the device, and the control panel of the inspection host 1 starts the electric push rod 6. The telescopic end of the electric push rod 6 drives the fixed shell 12 to move downward. Under the elastic force of the spring 14, the spring 14 drives the sliding column 13 to move downward synchronously through the fixed slide rail 7 until the extrusion block 15 fits and squeezes the upper side of the film. The telescopic end of the electric push rod 6 continues to drive the fixed shell 12 to move downward until it is fully extended. Then the electric push rod 6 is closed, and the fixed shell 12 slides downward along the sliding column 13. At the same time, the spring 14 is compressed. If the thickness of the film is As the degree increases, the distance that the fixed shell 12 moves along the sliding column 13 will increase, and the compression amount of the spring 14 will also increase. When the sliding column 13 moves downward, the sliding column 13 drives the fixed slide rail 7 to move downward synchronously, and the fixed slide rail 7 drives all the parts on it to move downward synchronously through the sliding members 8 on both sides. When the extrusion block 15 is attached to and squeezed to the upper side of the film, the extrusion rollers 9 on the left and right sides are also squeezed on both sides of the film. The extrusion rollers 9 and the adjacent rollers 5 squeeze each other to complete the extrusion of the film. In the above process, the slide bar 11 slides downward along the electric slider 4.

[0045] After completing the above work, the control panel of the detection host 1 starts the two electric sliders 4, and the two electric sliders 4 move away from each other. At the same time, the electric sliders 4 drive the connecting shell 10 and the adjacent sliding parts 8 to move synchronously through the slide rod 11, and the rollers 5 and the squeezing rollers 9 on the same side squeeze each other, thereby applying tension to both sides of the film, so that the film is flattened on the upper side of the detection host 1. When the electric slider 4 moves to the top of the adjacent guide rail 3, the control panel of the detection host 1 closes the two electric sliders 4 and flattens the film to the left and right sides, thereby reducing the degree of bending of the film and weakening the influence of the creases of the film on its transmittance, thereby improving the accuracy of the device in detecting the transmittance of the film.

[0046] The detection host 1 cooperates with the detection probe 2 to detect the flattened film, and then the detection value is displayed on the control panel of the detection host 1. After the detection is completed, the control panel of the detection host 1 starts the electric push rod 6, so that the telescopic end of the electric push rod 6 drives the parts on it to move upward and reset. The electric push rod 6 is closed after the telescopic end is reset. During the resetting of the telescopic end of the electric push rod 6, the fixed slide rail 7 drives the two sliding parts 8 and the parts on them to move upward and reset. Then the control panel of the detection host 1 starts the two electric sliders 4, so that the two electric sliders 4 move close to each other and reset. During the resetting process, the electric slider 4 moves the two sliding parts 8 close to each other and resets. The control panel closes the two electric sliders 4, and the inspection personnel removes the film after the inspection from the upper side of the detection host 1 to prepare for the next inspection.

[0047] Example 2: Based on Example 1, Figure 4 、 Figure 7 and Figure 8, also includes: two sets of resistance adjustment mechanisms, the resistance adjustment mechanism is arranged between the sliding member 8 and the adjacent connecting shell 10, the resistance adjustment mechanism includes: a first connecting block 16, the first connecting block 16 is fixed to the rear end of the squeezing roller 9, the first connecting block 16 is located in the connecting shell 10, and the rear side of the connecting shell 10 is splined with a connecting rod 17; a second connecting block 18, fixed to the front end of the connecting rod 17 and located in the connecting shell 10, and the connecting rod 17 is provided with a thread; a fixing frame 19, fixed to the rear side of the connecting shell 10, the fixing frame 19 is rotatably connected to a threaded sleeve 20, and the threaded sleeve 20 is threadedly connected to the thread of the connecting rod 17; a fixing rod 21 , fixed to one side of the threaded sleeve 20, the sliding member 8 is hinged with a hydraulic rod 22 through a mounting seat, the telescopic end of the hydraulic rod 22 is hinged to the fixed rod 21, two elastic oil bags are fixed between the fixed shell 12 and the sliding column 13, and the elastic oil bags are filled with hydraulic oil, the hydraulic rod 22 and the elastic oil bags are connected through an oil guide pipe, the first connecting block 16 and the second connecting block 18 are both composed of magnets distributed at intervals, and a gap is left between the first connecting block 16 and the second connecting block 18. The magnetic fields between the first connecting block 16 and the second connecting block 18 interact to apply rotational resistance to the squeezing roller 9, and the cross-sectional area of ​​the elastic oil bag is larger than the cross-sectional area of ​​the oil cavity of the hydraulic rod 22.

[0048] In the above scheme, the purpose is to avoid the membrane from being over-stretched, which causes the transmittance of the membrane to change, ensure that the membrane is in a uniformly flattened state, and improve the accuracy of the device in detecting the transmittance of the membrane. The connecting shell 10 is fixed to the adjacent sliding member 8 through a mounting seat, and a sealing ring is installed between the connecting shell 10 and the connecting rod 17. The connecting shell 10 mainly protects the first connecting block 16 and the adjacent second connecting block 18. The working process is as follows: After the extrusion block 15 squeezes the upper side of the membrane, the fixed shell 12 continues to move downward, and the hydraulic oil in the two elastic oil bags between the fixed shell 12 and the sliding column 13 flows into the two hydraulic rods 22 through the oil guide pipe. At this time, the second connecting block 18 is used to generate resistance to the adjacent first connecting block 16, providing resistance for the rotation of the extrusion roller 9. When the roller 5 and the extrusion roller 9 move synchronously, the roller 5 and the extrusion roller 9 both rotate, and the membrane is flattened by the friction force of the extrusion roller 9 on the membrane.

[0049] As the thickness of the film increases, and the magnetic field between the first connecting block 16 and the second connecting block 18 is used to ensure that the resistance to the rotation of the squeezing roller 9 remains the same, the discharge amount of the hydraulic oil between the fixed shell 12 and the sliding column 13 increases, and the extension length of the telescopic ends of the two hydraulic rods 22 increases. The telescopic ends of the hydraulic rods 22 drive the adjacent threaded sleeves 20 to rotate through the fixed rods 21, and the threaded sleeves 20 rotate along the fixed frame 19. The rotation angle of the threaded sleeves 20 increases with the extension length of the telescopic ends of the hydraulic rods 22. The threaded sleeves 20 use threads to drive the adjacent connecting rods. 17 slides along the connecting shell 10, and the connecting rod 17 drives the second connecting block 18 to move closer to the first connecting block 16, thereby reducing the gap between the first connecting block 16 and the second connecting block 18 and increasing the magnetic field strength between the first connecting block 16 and the second connecting block 18, thereby increasing the thickness of the film. The magnetic field strength between the first connecting block 16 and the second connecting block 18 is increased, and the resistance of the squeezing roller 9 when rotating is increased to increase the pulling force on the film to both sides, so that the film is in a flat state on the upper side of the detection host 1, reducing the influence of creases on the detection accuracy of the film transmittance.

[0050] After the transmittance of the film is detected, the telescopic end of the electric push rod 6 moves upward and resets. At this time, under the action of the elastic force of the spring 14, the sliding column 13 slides and resets along the fixed shell 12, the elastic oil bag in the fixed shell 12 and the sliding column 13 resets, the telescopic ends of the two hydraulic rods 22 reset, and under the drive of the threaded sleeve 20, the connecting rod 17 drives the second connecting block 18 to reset, and then repeats the above operation to reset all parts of the device. The above is a detailed description of the embodiment of the present invention in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiment. Various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the purpose of the present invention.

Claims

1. A light transmittance detection device for agricultural film production, characterized in that: Includes: Detect host; The detection probe is fixed to the upper side of the detection host through a column. Guide rails are installed on both sides of the detection host. The guide rails are slidably connected to electric sliders, and the electric sliders are rotatably connected to rollers. An electric push rod is fixedly connected to the column of the detection host. The telescopic end of the electric push rod is provided with a squeezing assembly, which is used to pre-fix the agricultural film sample. The squeezing assembly is installed with a fixed slide rail, and slide grooves are provided on both sides of the fixed slide rail. The fixed slide rail is located above the guide rail. Two sliding members are provided, and the two sliding members are respectively slidably connected to the slide grooves of the fixed slide rails. The sliding members are rotatably connected to the squeezing rollers. The side of the sliding member away from the squeezing rollers is fixedly connected to a connecting shell. The side of the connecting shell close to the electric slider is fixedly connected to a sliding rod. The sliding rod passes through the adjacent electric sliders and the two are slidably connected. The squeezing roller and the adjacent rollers clamp the agricultural film and stretch it to both sides, so that the agricultural film is flattened on the upper side of the detection host; The extrusion assembly includes: A fixed housing is fixedly connected to the telescopic end of the electric push rod, and the fixed housing is slidably connected to a sliding column, and the sliding column passes through the fixed slide rail and the two are fixedly connected; a spring, sleeved on the outside of the sliding column, with two ends of the spring respectively fixed to the fixed housing and the fixed slide rail; An extrusion block is fixed to the lower end of the sliding column and is used to pre-fix the agricultural film sample; Also included are: Two sets of resistance adjustment mechanisms, each of which is provided between the sliding member and the adjacent connecting shell, and includes: a first connecting block, the first connecting block being fixedly connected to one end of the squeezing roller close to the connecting shell, the first connecting block being located in the connecting shell, and a connecting rod being spline-connected to a side of the connecting shell away from the squeezing roller; a second connecting block, fixedly connected to one end of the connecting rod close to the first connecting block and located in the connecting shell, wherein the connecting rod is provided with threads; A fixing frame is fixedly connected to a side of the connecting shell away from the sliding member, the fixing frame is rotatably connected to a threaded sleeve, and the threaded sleeve is threadedly connected to the thread of the connecting rod; A fixed rod is fixedly connected to one side of the threaded sleeve. The sliding member is hingedly connected to a hydraulic rod through a mounting seat. The telescopic end of the hydraulic rod is hingedly connected to the fixed rod. Two elastic oil bags are fixedly connected between the fixed shell and the sliding column. The elastic oil bags are filled with hydraulic oil. The hydraulic rod and the elastic oil bags are connected through an oil guide pipe. The first connecting block and the second connecting block are both composed of magnets distributed at intervals, and a gap is left between the first connecting block and the second connecting block.

2. A light transmittance detection device for agricultural film production according to claim 1, characterized in that: The squeezing roller is located directly above the supporting roller and is used to apply vertical squeezing force to the agricultural film sample.

3. A light transmittance detection device for agricultural film production according to claim 2, characterized in that: The upper side of the roller is flush with the upper side of the detection host, so that the agricultural film sample is always in contact with the upper side of the detection host during stretching.

4. A light transmittance detection device for agricultural film production according to claim 3, characterized in that: The outer sides of the supporting roller and the squeezing roller are both wrapped with anti-slip sleeves, which are used to increase the friction between the supporting roller, the squeezing roller and the agricultural film sample.

5. The light transmittance detection device for agricultural film production according to claim 1, characterized in that: The lower side of the extrusion block is configured to be made of a smooth material to reduce frictional resistance between the extrusion block and the agricultural film sample.

6. A light transmittance detection device for agricultural film production according to claim 5, characterized in that: The lower side of the squeezing block is flush with the lower side of the squeezing roller.

7. The light transmittance detection device for agricultural film production according to claim 1, characterized in that: The cross-sectional area of ​​the elastic oil bag is larger than the cross-sectional area of ​​the hydraulic rod oil chamber.

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