An oil cylinder self-protection control circuit and a hydraulic system with an online detection function

Abstract

An oil cylinder self - protection control circuit and a hydraulic system with an on - line detection function, including a pilot - operated check valve and a self - protection check valve. The conducting inlets of the pilot - operated check valve and the self - protection check valve intersect at a first intersection point. The first intersection point is connected to the rodless cavity of the oil cylinder and the control system. The control port of the pilot - operated check valve and the conducting outlet of the self - protection check valve intersect at a second intersection point. The second intersection point is connected to the oil source in series with a solenoid valve. A pressure transmitter is connected to the main oil path at the outlet of the solenoid valve through a branch oil path; a self - protection test valve is connected between the second intersection point and the solenoid valve, and the self - protection test valve is connected to the oil source through a detection branch. In the present invention, the pressure of the rodless cavity of the oil cylinder is introduced through the self - protection check valve and is logically controlled with the oil source pressure, so that the action of the pilot - operated check valve is not affected by the oil source pressure. The control oil path of the pilot - operated check valve is not controlled by the solenoid valve through the self - protection test valve, and the reliability of the power - off action of the solenoid valve is automatically judged through the pressure transmitter.

Description

Technical Field

[0001] The present invention relates to the technical field of electro-hydraulic control, and particularly to an oil cylinder self-holding control circuit and a hydraulic system with an on-line detection function. Background Art

[0002] Existing single-acting electro-hydraulic actuators are widely used in valve control and achieve the reset action through a spring box therein. However, since there is always a relatively large force acting on the actuator from the spring box, the self-holding structure of the electro-hydraulic actuator is prone to generating false self-holding actions when the hydraulic system fails to build up pressure. Specifically, when the oil source pressure drops, the force exerted by the oil source pressure on the hydraulic control check valve is less than the force transmitted to the hydraulic control check valve through the hydraulic oil from the spring box, and the hydraulic control check valve opens, resulting in false self-holding actions, leading to the shutdown of the entire device, which greatly affects the process performance and enterprise profits. In addition, it is impossible to timely detect the hidden danger of unreliable power-off actions of the solenoid valve in the self-holding control device due to long-term power-on, which may cause the equipment to run away. Summary of the Invention

[0003] Based on this, the object of the present invention is to provide an oil cylinder self-holding control circuit with an on-line detection function to avoid generating false self-holding actions and the hidden danger of unreliable power-off actions of the solenoid valve.

[0004] An oil cylinder self-holding control circuit with an on-line detection function includes:

[0005] A hydraulically controlled check valve and a self-holding check valve arranged in parallel. The conducting inlets of the hydraulically controlled check valve and the self-holding check valve intersect at a first intersection point. The first intersection point is respectively connected to the rodless cavity of the oil cylinder and the control system. The control port of the hydraulically controlled check valve and the conducting outlet of the self-holding check valve intersect at a second intersection point. The second intersection point is sequentially connected to at least one solenoid valve in series and then connected to the oil source, and a pressure transmitter is connected to the main oil path at the outlet of each solenoid valve through a branch oil path.

[0006] A self-holding test valve, which is connected between the second intersection point and the nearest solenoid valve, and the self-holding test valve is also connected to the oil source through a detection branch. When in the normal working state, the oil source, the solenoid valve, the working valve position of the self-holding test valve and the second intersection point are connected. When in the on-line detection state, the oil source, the detection valve position of the self-holding test valve and the second intersection point are connected, switching the solenoid valve from the powered-on state to the powered-off state, and automatically detecting a change in pressure through the pressure transmitter to determine the failure of the power-off action of the solenoid valve.

[0007] Compared with the prior art, in the present invention, a self-protection one-way valve is provided on the control oil circuit of the hydraulically controlled one-way valve, thereby introducing the pressure of the rodless chamber of the oil cylinder and logically controlling it with the oil source pressure, so that the action of the hydraulically controlled one-way valve is not affected by the oil source pressure and no accidental self-protection action will occur. By providing a self-protection test valve, the control oil circuit of the hydraulically controlled one-way valve is not controlled by the solenoid valve, and the reliability of the solenoid valve's power-off action is automatically judged by the pressure transmitter.

[0008] Furthermore, a first overflow valve and a first one-way valve are connected in series on the detection branch, and a conducting inlet of the first one-way valve is connected to an oil source.

[0009] Furthermore, a second overflow valve and a second one-way valve are connected in series between the solenoid valve farthest from the second intersection and the oil source in the main oil circuit, and a conducting inlet of the second one-way valve is connected to the oil source.

[0010] Furthermore, the pressure transmitter is connected to the branch oil circuit via a transmitter stop valve.

[0011] Furthermore, the branch oil circuit is also connected to a first pressure gauge via a first pressure cut-off valve, and the first pressure cut-off valve and the transmission cut-off valve intersect at one point on the branch oil circuit.

[0012] Furthermore, the second intersection is connected to a second pressure gauge via a second pressure cut-off valve.

[0013] Furthermore, the oil cylinder is a single-acting electro-hydraulic actuator.

[0014] A hydraulic system comprises an oil cylinder and further comprises the above-mentioned oil cylinder self-protection control circuit with online detection function, wherein the oil cylinder self-protection control circuit with online detection function is connected to the rodless chamber of the oil cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a hydraulic principle diagram when the oil cylinder self-protection control circuit with online detection function in the present invention is in a normal working state;

[0016] Figure 2 for Figure 1 The hydraulic principle diagram of the cylinder self-protection control circuit with online detection function in the online detection state;

[0017] Figure 3 for Figure 2 A hydraulic principle diagram for detecting whether the solenoid valve near the oil source fails due to power failure;

[0018] Figure 4 for Figure 2 The hydraulic principle diagram for detecting whether the solenoid valve near the self-protection test valve fails due to power failure.

[0019] Description of main component symbols:

[0020]

[0021] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. Specific embodiments

[0022] For ease of understanding the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided so that the disclosure of the present invention is thorough and complete.

[0023] It should be noted that when an element is referred to as being "fixedly provided on" another element, it can be directly on the other element or there can also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0025] Please refer to Figures 1 to 4 , a kind of oil cylinder self-protection control circuit with an on-line detection function provided in an embodiment of the present invention, comprising:

[0026] A pilot-operated check valve 10 and a self-protection check valve 11 arranged in parallel. The conducting inlets of the pilot-operated check valve 10 and the self-protection check valve 11 intersect at a first intersection point. The first intersection point is respectively connected to the rodless cavity of the oil cylinder 12 and the control system. The control port of the pilot-operated check valve 10 and the conducting outlet of the self-protection check valve 11 intersect at a second intersection point. The second intersection point is sequentially connected to at least one solenoid valve 13 in series and then connected to the oil source. And a pressure transmitter 14 is connected to the main oil path at the outlet of each solenoid valve 13 through a branch oil path;

[0027] A self-protection test valve 15, the self-protection test valve 15 is connected between the second intersection point and the nearest solenoid valve 13, and the self-protection test valve 15 is also connected to the oil source through a detection branch.

[0028] It should be noted that in the hydraulic system of the present invention, since the solenoid valve 13 is generally in the energized state, the spring in the solenoid valve 13 is compressed for a long time. When the solenoid valve 13 is switched from the energized state to the de-energized state, it is easy to cause the failure of the de-energized operation of the solenoid valve 13. Therefore, it is necessary to detect the solenoid valve 13. However, in order not to affect the normal operation of the hydraulic system, a self-holding test valve 15 is provided so that the control oil circuit of the hydraulic check valve 10 is not controlled by the solenoid valve 13 to achieve the normal connection of the oil circuit. At the same time, the solenoid valve 13 can also be detected online through the pressure transmitter 14. Specifically, in the present invention, when the self-holding control loop of the oil cylinder is in the normal working state, the oil source, the solenoid valve 13, the working valve position of the self-holding test valve 15 and the second intersection point are connected; when the self-holding control loop of the oil cylinder is in the online detection state, the oil source, the detection valve position of the self-holding test valve 15 and the second intersection point are connected, the solenoid valve 13 is switched from the energized state to the de-energized state, and a pressure change is automatically detected through the pressure transmitter 14 to determine the failure of the de-energized operation of the solenoid valve 13.

[0029] Further, when the pressure transmitter 14 automatically detects a pressure change, it is determined that the de-energized operation of the solenoid valve 13 fails; otherwise, it indicates that the de-energized operation of the solenoid valve 13 is normal.

[0030] In a preferred embodiment of the present invention, two solenoid valves 13 are provided, and the solenoid valves 13 are directional solenoid valves. When one of the solenoid valves is de-energized, the system will activate self-holding, making the system safer.

[0031] It should be further clarified that by providing a self-holding check valve 11 on the control oil circuit of the hydraulic check valve 10, introducing the pressure of the rodless cavity of the oil cylinder 12, and performing logical control with the oil source pressure, the operation of the hydraulic check valve 10 is not affected by the oil source pressure, and no false self-holding operation will occur. Specifically, when the self-holding control loop of the oil cylinder is in the normal working state, the oil source, the solenoid valve 13, the working valve position of the self-holding test valve 15 and the second intersection point are connected, that is, all the solenoid valves 13 are energized, the control port of the hydraulic check valve 10 is connected to the high pressure of the oil source, and at this time the hydraulic check valve 10 is in the closed state; when any one of the solenoid valves 13 is de-energized, the hydraulic check valve 10 is connected to the low pressure of the oil source, and the force of the spring box in the oil cylinder 12 is conducted from the rodless cavity to the hydraulic check valve 10, causing the hydraulic check valve 10 to open and realizing the self-holding function.

[0032] Please refer to Figures 2 to 4Preferably, the detection branch is connected in series with a first relief valve 16 and a first non-return valve 17, and the conducting inlet of the first non-return valve 17 is connected to the oil source. Specifically, when the oil cylinder self-protection control circuit is in an online detection state and works normally, the first relief valve 16 does not work, the first non-return valve 17 is turned on, and the high pressure of the oil source passes through the first non-return valve 17, the detection valve position of the self-protection test valve 15, the second intersection and the control port of the hydraulic control non-return valve 10; when the oil cylinder self-protection control circuit is in an online detection state and does not work normally, the first relief valve 16 works, the first non-return valve 17 is turned off, and the control port of the hydraulic control non-return valve 10 is connected to the low pressure of the oil source through the second intersection, the detection valve position of the self-protection test valve 15 and the first relief valve 16 in sequence.

[0033] See also Figure 4 , a second relief valve 18 and a second non-return valve 19 are connected in series between the solenoid valve 13 farthest from the second intersection in the main oil circuit and the oil source, and the conducting inlet of the second non-return valve 19 is connected to the oil source. Specifically, when the oil cylinder self-protection control circuit is in normal working state, the second relief valve 18 does not work, the second non-return valve 19 is turned on, and the high pressure of the oil source passes through the second non-return valve 19, the working valve position of the self-protection test valve 15, the second intersection and the control port of the hydraulic control non-return valve 10; when the oil cylinder self-protection control circuit is in normal working state and in abnormal state, the second relief valve 18 works, the second non-return valve 19 is turned off, and the control port of the hydraulic control non-return valve 10 is connected to the low pressure of the oil source through the second intersection, the detection valve position of the self-protection test valve 15 and the second relief valve 18 in sequence.

[0034] See also Figures 2 to 4 The pressure transmitter 14 is connected to the branch oil circuit via a transmitter stop valve 20. When online detection is required, the transmitter stop valve 20 is opened, and the pressure transmitter 14 is connected to the branch oil circuit; when online detection is not required, the transmitter stop valve 20 is closed, and the pressure transmitter 14 is not connected to the branch oil circuit.

[0035] See also Figures 2 to 4 The branch oil circuit is also connected to the first pressure gauge 22 through the first pressure stop valve 21, and the first pressure stop valve 21 and the transmitter stop valve 20 intersect at one point on the branch oil circuit. This is equivalent to setting two parallel detection points on the branch oil circuit, that is, the pressure at the outlet of the solenoid valve 13 can be manually detected through the first pressure gauge 22, or the pressure at the outlet of the solenoid valve 13 can be automatically detected through the pressure transmitter 14.

[0036] See also Figures 1 to 4, the second intersection point is connected to a second pressure gauge 24 through a second pressure cut-off valve 23, that is, the pressure at the control port of the pilot-operated check valve 10 is manually detected through the second pressure gauge 24.

[0037] In another preferred embodiment of the present invention, the oil cylinder 12 is a single-acting electro-hydraulic actuator.

[0038] In summary, in the present invention, by providing a self-holding check valve 11 on the control oil circuit of the pilot-operated check valve 10, introducing the pressure of the rodless cavity of the oil cylinder 12, and performing logical control with the oil source pressure, the operation of the pilot-operated check valve 10 is not affected by the oil source pressure, and no false self-holding operation will occur. By providing a self-holding test valve 15, the control oil circuit of the pilot-operated check valve 10 is not controlled by the solenoid valve, and the reliability of the power-off operation of the solenoid valve 13 is automatically judged by the pressure transmitter 14.

[0039] In addition, the present invention also discloses a hydraulic system, including an oil cylinder 12, and further including an oil cylinder self-holding control circuit with an online detection function as disclosed in the above embodiments. The oil cylinder self-holding control circuit with an online detection function is connected to the rodless cavity of the oil cylinder 12. Therefore, the hydraulic system including the oil cylinder self-holding control circuit with an online detection function also has all the above technical effects.

[0040] In this specification, the various embodiments are described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other.

[0041] The above embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

1. A cylinder self-protection control circuit with online detection function, It is characterized in that include: A hydraulically controlled one-way valve and a self-protecting one-way valve are arranged in parallel, wherein the conducting inlets of the hydraulically controlled one-way valve and the self-protecting one-way valve intersect at a first intersection, the first intersection is respectively connected to the rodless chamber of the oil cylinder and the control system, the control port of the hydraulically controlled one-way valve and the conducting outlet of the self-protecting one-way valve intersect at a second intersection, the second intersection is sequentially connected in series with at least one solenoid valve and then connected to an oil source, and a pressure transmitter is connected to the outlet main oil circuit of each solenoid valve through a branch oil circuit; A self-protection test valve, the self-protection test valve is connected between the second intersection and the nearest solenoid valve, and the self-protection test valve is connected to the oil source through a detection branch at the same time. When in a normal working state, the oil source, the solenoid valve, the working valve position of the self-protection test valve are connected to the second intersection. When in an online detection state, the oil source, the detection valve position of the self-protection test valve are connected to the second intersection, and the solenoid valve is switched from an energized state to a de-energized state. The pressure transmitter automatically detects a pressure change to determine that the de-energized action of the solenoid valve has failed; A first overflow valve and a first one-way valve are connected in series on the detection branch, and a conducting inlet of the first one-way valve is connected to an oil source; A second relief valve and a second one-way valve are connected in series between the solenoid valve farthest from the second intersection in the main oil circuit and the oil source, and a conducting inlet of the second one-way valve is connected to the oil source; The pressure transmitter is connected to the branch oil circuit via a transmitter stop valve; The branch oil circuit is also connected to a first pressure gauge via a first pressure cut-off valve, and the first pressure cut-off valve and the transmission cut-off valve intersect at one point on the branch oil circuit; The second intersection point is connected to a second pressure gauge via a second pressure cut-off valve.

2. The oil cylinder self-protection control circuit with online detection function according to claim 1, It is characterized in that The cylinder is a single-acting electro-hydraulic actuator.

3. A hydraulic system comprising a cylinder, It is characterized in that It further comprises the oil cylinder self-protection control circuit with online detection function as claimed in claim 1 or 2, and the oil cylinder self-protection control circuit with online detection function is connected to the rodless chamber of the oil cylinder.

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