A multi-speed hydraulic cylinder system and its control method

Abstract

This invention relates to the field of hydraulic cylinder system technology, and in particular to a multi-speed hydraulic cylinder system and control method, comprising an oil tank, a reversible first pump, and several hydraulic cylinders. The reversible output ends of the first pump are connected to the oil tank via a first pipeline. A one-way valve is installed on each of the first pipelines between the reversible output ends of the first pump and the oil tank to prevent oil backflow into the oil tank. The forward output end of the first pump is connected to the first chamber at one end of the hydraulic cylinder via a second pipeline. In use, by controlling a first proportional throttling component or a second proportional throttling component and changing the oil return volume of the first or second chamber of the hydraulic cylinder, the operating speed of the hydraulic cylinder is changed. The system is compact and small overall. Oil suction and return can utilize the oil in the pipeline, enabling circulation and avoiding the problem of maintaining a certain temperature for samples of various specifications and steel grades during furnace baking.

Description

Technical Field

[0001] This invention relates to the field of hydraulic cylinder system technology, and in particular to a multi-speed hydraulic cylinder system and control method. Background Technology

[0002] Currently, in bar production systems, to ensure that bar samples meet a series of testing requirements and guarantee the accuracy of sample bar testing, it is necessary to maintain a relatively constant temperature during bar testing. Therefore, improving the heating quality of bar samples while maintaining specific temperature requirements for samples of various specifications and steel grades during furnace drying is a current challenge. Summary of the Invention

[0003] The technical problem to be solved by this invention is: in order to solve the problem of how to achieve uniform heating of samples of various specifications and steel grades in the furnace, a multi-speed hydraulic cylinder system and control method are provided.

[0004] The technical solution adopted by the present invention to solve its technical problem is: a multi-speed hydraulic cylinder system, including an oil tank, a first pump that can rotate forward and backward, and several hydraulic cylinders. The forward and reverse output ends of the first pump are connected to the oil tank through a first pipeline. A liquid inlet check valve is provided on the first pipeline between the forward and reverse output ends of the first pump and the oil tank. The liquid inlet check valve is used to prevent oil from flowing back into the oil tank. The forward output end of the first pump is connected to the first chamber at one end of the hydraulic cylinder through a second pipeline. The first chamber and the second chamber between two adjacent hydraulic cylinders are connected through a third pipeline. The reverse output end of the first pump is connected to the second chamber at the other end of the hydraulic cylinder through a fourth pipeline. The first pump and several hydraulic cylinders are connected in series. A first sequence valve and a second sequence valve are connected in parallel on the pipeline between the first chamber and the second chamber of the hydraulic cylinder. The first sequence valve and the second sequence valve are arranged in opposite directions.

[0005] A first proportional throttling component is provided on the pipeline connected to the first chamber of the hydraulic cylinder, and a second proportional throttling component is provided on the pipeline connected to the second chamber of the hydraulic cylinder. The first sequence valve is located between the second sequence valve and the hydraulic cylinder, and both the first proportional throttling component and the second proportional throttling component are located between the first sequence valve and the hydraulic cylinder.

[0006] When the first pump rotates forward to supply oil, the oil enters the first chamber of the oil cylinder through the first proportional throttling component. The second proportional throttling component is used to control the return oil volume of the second chamber and to generate pressure in the first chamber.

[0007] When the second pump reverses its oil supply, the oil enters the second chamber of the cylinder through the second proportional throttling component. The first proportional throttling component controls the return oil volume of the first chamber and creates pressure in the second chamber. Compared to existing technologies, this solution controls either the first or second proportional throttling component, changes the return oil volume of the first or second chamber of the cylinder, and alters the cylinder's operating speed. The system is compact and efficient, and oil suction and return can utilize the oil in the pipeline, enabling circulation.

[0008] In some preferred embodiments, the system further includes a three-position four-way valve, a two-position two-way valve, and a second pump. The A port of the three-position four-way valve is connected to the reverse output end of the first pump via a fourth pipeline. The B port of the three-position four-way valve is connected to the A port of the two-position two-way valve. The P port of the two-position two-way valve is connected to the forward output end of the first pump via a fifth pipeline. The P port of the three-position four-way valve is connected to the oil tank via a sixth pipeline. The second pump is located on the sixth pipeline. The T port of the three-position four-way valve is connected to the oil tank via a seventh pipeline. A first hydraulically controlled check valve is installed on a second pipeline between the forward output end of the first pump and the first chamber at one end of the cylinder. A second hydraulically controlled check valve is installed on a fourth pipeline between the reverse output end of the first pump and the second chamber at the other end of the cylinder. The first hydraulically controlled check valve, the second hydraulically controlled check valve, and the three-position four-way valve are all signal-connected to the two-position two-way valve.

[0009] In some preferred embodiments, a first one-way high-pressure filter assembly is provided on a second pipeline between the forward output end of the first pump and the first chamber at one end of the oil cylinder. The first one-way high-pressure filter assembly is used to unidirectionally transport and filter the oil when the first pump outputs in the forward direction. A second one-way high-pressure filter assembly is provided on a fourth pipeline between the reverse output end of the first pump and the second chamber at the other end of the oil cylinder. The second one-way high-pressure filter assembly is used to unidirectionally transport and filter the oil when the first pump outputs in the reverse direction.

[0010] In some preferred embodiments, both the first one-way high-pressure filter assembly and the second one-way high-pressure filter assembly include a first one-way valve, a second one-way valve, and a filter. The first one-way valve and the filter are connected in series, and the second one-way valve is connected in parallel with the first one-way valve and the filter. The first one-way valve and the second one-way valve are arranged in opposite directions, and the first one-way valve is arranged corresponding to the first hydraulically controlled one-way valve or the second hydraulically controlled one-way valve on its pipeline.

[0011] In some preferred embodiments, a differential pressure transmitter is connected in parallel across the two ends of the filter.

[0012] In some preferred embodiments, a return oil filter is provided on the seventh pipeline between the T port of the three-position four-way valve and the oil tank.

[0013] In some preferred embodiments, both the first proportional throttling assembly and the second proportional throttling assembly include a throttling valve and a check valve, the throttling valve and the check valve are arranged in parallel, and the throttling valve and the check valve on the pipeline corresponding to the first chamber and the second chamber of the oil cylinder are arranged in the same direction.

[0014] In some preferred embodiments, a ball valve is connected in parallel on the pipeline between the first chamber and the second chamber of the hydraulic cylinder.

[0015] In some preferred embodiments, the cylinder is a double-rod cylinder.

[0016] According to the above-described control method for a multi-speed hydraulic cylinder system, when the first pump is working, oil is drawn from the oil tank and enters the first pump through one of the inlet check valves. The first pump supplies oil and simultaneously opens the first hydraulic check valve and the second hydraulic check valve. The oil is filtered through one of the first and second one-way high-pressure filter groups on the side where the oil is supplied. The filtered pressurized oil enters one of the first and second chambers of the hydraulic cylinder. The oil in the other of the first and second chambers of the preceding hydraulic cylinder enters one of the first and second chambers of the next hydraulic cylinder. Finally, the oil is drawn from the pipeline into the first pump for circulation and transportation, realizing the sequential operation of several hydraulic cylinders.

[0017] When it is necessary to adjust the operating speed of several hydraulic cylinders, adjust the throttle valve on the pipeline connected to the first chamber of the hydraulic cylinder and the throttle valve on the pipeline connected to the second chamber of the hydraulic cylinder to adjust to the required operating speed of the several hydraulic cylinders.

[0018] When the oil pressure in the first delivery direction oil circuit exceeds the pressure set by the first sequence valve or the second sequence valve, the first sequence valve or the second sequence valve that is in the same delivery direction as the first pump is opened.

[0019] When it is necessary to operate some of the cylinders in a group of cylinders, open the ball valve corresponding to the other group of cylinders in the group of cylinders;

[0020] When the oil pressure provided by the first pump is insufficient, the second pump opens, the three-position four-way valve switches between the left and right positions, and the two-position two-way valve opens to supply oil to the cylinder for pressure replenishment.

[0021] When the oil in the tank needs to be filtered, turn on the second pump, the three-position four-way valve is in the neutral position, and the oil is filtered through the return oil filter.

[0022] The beneficial effects of the present invention are as follows: When the multi-speed hydraulic cylinder system and control method of the present invention are used, by controlling the first proportional throttling component or the second proportional throttling component and changing the oil return volume of the first or second chamber of the hydraulic cylinder, the action speed of the hydraulic cylinder is changed. The system is small and compact as a whole. Oil suction and oil return can utilize the oil in the pipeline, which can realize circulation and avoid the problem that it is difficult to maintain a certain temperature requirement for samples of various specifications and steel grades during the furnace baking process. Attached Figure Description

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] Figure 1 This is a schematic diagram of the structure of the present invention.

[0025] In the diagram: 1. Oil tank, 2. First pump, 3. Oil cylinder, 4. Inlet check valve, 5. First sequence valve, 6. Second sequence valve, 7. Three-position four-way valve, 8. Two-position two-way valve, 9. Second pump, 10. First hydraulic control check valve, 11. Second hydraulic control check valve, 12. First check valve, 13. Second check valve, 14. Filter, 15. Differential pressure transmitter, 16. Return oil filter, 17. Throttle valve, 18. Check valve, 19. Ball valve, 20. First chamber, 21. Second chamber. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to the embodiments:

[0027] This invention is not limited to the specific embodiments listed below. Those skilled in the art can implement this invention using various other specific embodiments based on the content disclosed herein. Any modifications or alterations made to the design structure and concept of this invention fall within the protection scope of this invention. It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0028] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention 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 the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0029] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0030] like Figure 1 As shown, a multi-speed hydraulic cylinder system includes an oil tank 1, a reversible first pump 2, three hydraulic cylinders 3, a three-position four-way valve 7, a two-position two-way valve 8, and a second pump 9. The hydraulic cylinders 3 include, but are not limited to, double-rod cylinders 3 and single-rod cylinders 3. In this embodiment, all three cylinders 3 are double-rod cylinders 3. The reversible output ends of the first pump 2 are connected to the oil tank 1 via a first pipeline. A one-way valve 4 is installed on each of the first pipelines between the reversible output ends of the first pump 2 and the oil tank 1. The one-way valve 4 is used to prevent oil from flowing back into the oil tank 1. Between adjacent cylinders 3... The first chamber 20 and the second chamber 21 are connected by a third pipeline, so that the three oil cylinders 3 are connected in series. The forward rotation output end of the first pump 2 is connected to the first chamber 20 at one end of the first oil cylinder 3 by a second pipeline. The reverse rotation output end of the first pump 2 is connected to the second chamber 21 at the other end of the third oil cylinder 3 by a fourth pipeline, so that the first pump 2 and the three oil cylinders 3 are connected in series. A first sequence valve 5 and a second sequence valve 6 are connected in parallel on the pipeline between the first chamber 20 and the second chamber 21 of the oil cylinder 3. The first sequence valve 5 and the second sequence valve 6 are set in opposite directions to each other.

[0031] The A port of the three-position four-way valve 7 is connected to the reverse output end of the first pump 2 via a fourth pipeline. The B port of the three-position four-way valve 7 is connected to the A port of the two-position two-way valve 8. The P port of the two-position two-way valve 8 is connected to the forward output end of the first pump 2 via a fifth pipeline. The P port of the three-position four-way valve 7 is connected to the oil tank 1 via a sixth pipeline. The second pump 9 is installed on the sixth pipeline. The T port of the three-position four-way valve 7 is connected to the oil tank 1 via a seventh pipeline. A first hydraulic control check valve 10 is installed on the second pipeline between the forward output end of the first pump 2 and the first chamber 20 at one end of the cylinder 3. A second hydraulic control check valve 11 is installed on the fourth pipeline between the reverse output end of the first pump 2 and the second chamber 21 at the other end of the cylinder 3. The first hydraulic control check valve 10, the second hydraulic control check valve 11, and the three-position four-way valve 7 are all signal connected to the two-position two-way valve 8.

[0032] A first one-way high-pressure filter assembly is installed on the second pipeline between the forward output end of the first pump 2 and the first chamber 20 at one end of the oil cylinder 3. The first one-way high-pressure filter assembly is used to unidirectionally transport and filter the oil when the first pump 2 outputs in the forward direction. A second one-way high-pressure filter assembly is installed on the fourth pipeline between the reverse output end of the first pump 2 and the second chamber 21 at the other end of the oil cylinder 3. The second one-way high-pressure filter assembly is used to unidirectionally transport and filter the oil when the first pump 2 outputs in the reverse direction.

[0033] Both the first and second one-way high-pressure filter components include a first one-way valve 12, a second one-way valve 13, and a filter 14. The first one-way valve 12 and the filter 14 are connected in series, and the second one-way valve 13 is connected in parallel with the first one-way valve 12 and the filter 14. The first one-way valve 12 and the second one-way valve 13 are arranged in opposite directions. The first one-way valve 12 is arranged corresponding to the first hydraulically controlled one-way valve 10 or the second hydraulically controlled one-way valve 11 on its pipeline.

[0034] To prevent filter 14 from becoming clogged, a differential pressure transmitter 15 is connected in parallel across both ends of filter 14. A return oil filter 16 is installed on the seventh pipeline between the T port of the three-position four-way valve 7 and the oil tank 1. By connecting the differential pressure transmitter 15 in parallel across both ends of filter 14, the differential pressure transmitter 15 can detect the pressure difference of the oil across filter 14. When the pressure difference exceeds the range, the differential pressure transmitter 15 issues an alarm.

[0035] In order to control the operating speed of the hydraulic cylinder 3, a first proportional throttling component is provided on the pipeline connected to the first chamber 20 of the hydraulic cylinder 3, and a second proportional throttling component is provided on the pipeline connected to the second chamber 21 of the hydraulic cylinder 3. The first sequence valve 5 is located between the second sequence valve 6 and the hydraulic cylinder 3, and both the first proportional throttling component and the second proportional throttling component are located between the first sequence valve 5 and the hydraulic cylinder 3.

[0036] When the first pump 2 rotates forward to supply oil, the oil enters the first chamber 20 of the oil cylinder 3 through the first proportional throttling component. The second proportional throttling component is used to control the return oil volume of the second chamber 21 and to generate pressure in the first chamber 20.

[0037] When the second pump 9 reverses to supply oil, the oil enters the second chamber 21 of the oil cylinder 3 through the second proportional throttling component. The first proportional throttling component is used to control the return oil volume of the first chamber 20 and to generate pressure in the second chamber 21.

[0038] Both the first proportional throttling assembly and the second proportional throttling assembly include a throttling valve 17 and a check valve 18. The throttling valve 17 and the check valve 18 are arranged in parallel. The throttling valve 17 and the check valve 18 on the pipelines corresponding to the first chamber 20 and the second chamber 21 of the hydraulic cylinder 3 are arranged in the same direction.

[0039] To control the movement of the hydraulic cylinders 3, ball valves 19 are connected in parallel on the pipelines between the first chamber 20 and the second chamber 21 of the three hydraulic cylinders 3. By controlling the ball valves 19, the first proportional throttling component, and the second proportional throttling component, the oil in the ball valve 19 is directly delivered to the other hydraulic cylinder 3, thus better controlling the movement of the hydraulic cylinder 3. At the same time, if the hydraulic cylinder 3 becomes mechanically stuck, the ball valve 19 can open to contact the hydraulic cylinder 3 and cause mechanical movement, thus playing a safety protection role.

[0040] According to the above-described control method for a multi-speed hydraulic cylinder system, when the first pump 2 is working, it draws oil from the oil tank 1 and enters the first pump 2 through one of the inlet check valves 4. The first pump 2 supplies oil and simultaneously opens the first hydraulic check valve 10 and the second hydraulic check valve 11. The oil is filtered through one of the first and second one-way high-pressure filters 14 groups on the side where the oil is supplied. The filtered pressurized oil enters one of the first chamber 20 and the second chamber 21 of the hydraulic cylinder 3. The oil in the other of the first chamber 20 and the second chamber 21 of the previous hydraulic cylinder 3 enters one of the first chamber 20 and the second chamber 21 of the next hydraulic cylinder 3. Finally, the oil is drawn into the first pump 2 from the pipeline for circulation and transportation, thereby realizing the sequential action of several hydraulic cylinders 3.

[0041] When it is necessary to adjust the operating speed of several hydraulic cylinders 3, the throttle valve 17 on the pipeline connected to the first chamber 20 of the hydraulic cylinder 3 and the valve 17 on the pipeline connected to the second chamber 21 of the hydraulic cylinder 3 are adjusted to the required operating speed of several hydraulic cylinders 3.

[0042] When the oil pressure in the first conveying direction oil circuit exceeds the pressure set by the first sequence valve 5 or the second sequence valve 6, the first sequence valve 5 or the second sequence valve 6, which is in the same direction as the oil conveying of the first pump 2, is opened.

[0043] When it is necessary to operate some of the hydraulic cylinders 3, open the ball valve 19 corresponding to the other part of the hydraulic cylinders 3.

[0044] When the oil pressure provided by the first pump 2 is insufficient and lower than the set value, the second pump 9 opens, the three-position four-way valve 7 switches between the left and right positions, and the two-position two-way valve 8 opens, so that the second pump 9 can supply oil to the oil cylinder 3 to replenish the pressure, which can achieve the purpose of the second pump 9 continuing to supply oil after the first pump 2 is damaged.

[0045] When the oil in tank 1 needs to be filtered, the second pump 9 is turned on, the three-position four-way valve 7 is in the middle position, and the oil is filtered through the return oil filter 16 for the purpose of self-circulation filtration, thereby improving the cleanliness of the oil.

[0046] In use, the aforementioned multi-speed hydraulic cylinder system and control method draw oil from the oil tank 1 through one of the inlet check valves 4, allowing the first pump 2 to supply oil in the forward direction. Simultaneously, the first hydraulic check valve 10 and the second hydraulic check valve 11 are opened. The oil is then filtered through the one-way high-pressure filter group 14 on the right side. The filtered pressurized oil directly enters the upper first chamber 20 of the right-side hydraulic cylinder 3 through the check valve 18 of the first proportional throttling assembly, pushing the piston of the cylinder 3 downwards. Oil in the upper second chamber 21 of the cylinder 3 then enters... In the first chamber 20 of the next cylinder 3, the piston of the next cylinder 3 is pushed downward. The oil in the second chamber 21 of the next cylinder 3 then enters the last cylinder 3, pushing the piston of the last cylinder 3 downward. Finally, the oil is sucked into the pump from the pipeline. Then the first pump 2 reverses, sucking oil in the forward direction and supplying oil in the reverse direction. At this time, the operating principle is the same as the forward oil supply principle. The forward and reverse oil supply achieves the purpose of the cylinder 3 moving up or down reciprocating. If the pipeline does not leak, the design of the oil tank 1 can be very small and compact. The oil suction and return can be achieved by using the oil in the pipeline, which can realize circulation.

[0047] Regarding the speed control of cylinder 3, when the first pump 2 supplies oil in the forward direction, the oil enters the first chamber 20 of cylinder 3 through the one-way valve 18 of the first proportional throttling assembly, pushing the piston of cylinder 3 downward. The oil in the second chamber 21 of cylinder 3 passes through the second proportional throttling assembly. At this time, the opening of the throttle valve 17 on the second proportional throttling assembly is adjusted to 80%. Then, after the throttle valve 17 is closed by 20%, it will cause a certain pressure on the second chamber 21 of cylinder 3. For example, if the weight of the sample rod transported by the external load of cylinder 3 is 100kg, and the first sequence valve 5 is adjusted to overflow at 100kg, the first sequence valve 5 will open after reaching the upper limit pressure and will throttle the excess flow of 20% after throttling valve 17. The throttle valve 17 throttles 80% of the flow into the first chamber 20 of the next cylinder 3. If the speeds of the first and second cylinders 3 are set to be the same, the settings of the throttle valve 17 and the sequence valve of the second cylinder 3 are the same as those of the first cylinder 3. The oil enters the first chamber 20 of the third cylinder 3, pushing the piston of the third cylinder 3 downward. The oil in the second chamber 21 of the third cylinder 3 passes through the throttle valve 17. At this time, the proportional throttle valve 17 is 100% open. The oil returns to the first pump 2 through the pipeline. Thus, the speeds of each cylinder 3 are: the first and second cylinders 3 are at the same speed, and the third cylinder 3 is faster.

[0048] Alternatively, the first pump 2 supplies oil forward through the throttle valve 17 into the first chamber 20 of the first cylinder 3, pushing the piston of the first cylinder 3 downwards. Oil in the second chamber 21 then passes through the throttle valve 17, which is at 50% opening. When the throttle valve 17 is closed 50%, the second chamber 21 will experience some pressure buildup. For example, if the sample rod being transported by the external load of the first cylinder 3 weighs 100kg, and the sequence valve is adjusted to overflow at 100kg, then the first sequence valve 5 will open after reaching its upper limit pressure, throttling the excess oil in the throttle valve 17. 0% of the flow rate, along with 50% of the flow rate after throttling by the throttle valve 17, enters the first chamber 20 of the next cylinder 3. The oil enters the first chamber 20 of the second cylinder 3, pushing the piston of the second cylinder 3 downward. The oil in the second chamber 21 passes through the throttle valve 17, which is now 100% open. The oil then flows through the pipeline to the third cylinder 3. If the second and third cylinders 3 are set to the same speed, then the speeds of each cylinder 3 are: medium speed for the first cylinder 3, and high speed for the second and third cylinders 3.

[0049] Alternatively, the first pump 2 supplies oil forward through the throttle valve 17 into the first chamber 20 of the first cylinder 3, pushing the piston of the first cylinder 3 downwards. Oil in the second chamber 21 then passes through the throttle valve 17, which is at 50% opening. When the throttle valve 17 is closed 50%, the second chamber 21 will experience some pressure buildup. For example, if the sample rod being transported by the external load of the first cylinder 3 weighs 100kg, and the sequence valve 1 is adjusted to overflow at 100kg, then the first sequence valve 5 will open after reaching its upper limit pressure, thus throttling the excess oil from the throttle valve 17. 20% of the flow rate, along with 80% of the flow rate after throttling by the throttle valve 17, enters the first chamber 20 of the next cylinder 3. The oil enters the first chamber 20 of the second cylinder 3, pushing the piston of cylinder 3 downward. The oil in the second chamber 21 passes through the throttle valve 17, at which point the proportional throttle valve 17 is 100% open. The oil then flows through the pipeline to the third cylinder 3. If the speeds of the first cylinder 3 and the third cylinder 3 are set to be the same, it can be known that the speeds of each cylinder 3 are: medium speed for the first cylinder 3 and the third cylinder 3, and fast speed for the second cylinder 3.

[0050] Alternatively, the first pump 2 supplies oil in the forward direction, which enters the first chamber 20 of the first cylinder 3 through the throttle valve 17, pushing the piston of cylinder 3 downward. The oil in the second chamber 21 passes through the throttle valve 17, which is now 100% open, and enters the first chamber 20 of the second cylinder 3, pushing the piston of cylinder 3 downward. The oil in the second chamber 21 passes through the throttle valve 17, which is now 100% open, and then flows through the pipeline to the third cylinder 3. If the speeds of the first, second, and third cylinders 3 are set to be the same, then the speeds of each cylinder 3 are: the first, second, and third cylinders 3 are at the same speed.

[0051] Alternatively, the first pump 2 supplies oil forward through the throttle valve 17 into the first chamber 20 of the first cylinder 3, pushing the piston of the first cylinder 3 downwards. Oil in the second chamber 21 passes through the throttle valve 17, which is now open at 80%. When the throttle valve 17 is closed by 20%, the second chamber 21 will experience some pressure. For example, if the sample rod being transported by the external load of the first cylinder 3 weighs 100kg, and the sequence valve is adjusted to overflow at 100kg, then the first sequence valve 5 will open after reaching its upper limit pressure, throttling the excess flow (20%) from the throttle valve 17, along with the throttled 80% flow, into the first chamber 20 of the next cylinder 3, pushing the piston of the second cylinder 3 downwards. Oil in the second chamber 21 passes through the throttle valve 17, which is now open at 60%. When the throttle valve 17 is closed by 40%, the second chamber 21 will experience some pressure. For example, if the sample rod being transported by the external load of the second cylinder 3 weighs 10kg... 0kg, the sequence valve is adjusted to 100kg overflow at this time. Then, after the first sequence valve 5 reaches the upper limit pressure, it opens and will throttle the excess 40% of the flow after throttling by the throttle valve 17, and together with the 60% of the flow after throttling by the throttle valve 17, it enters the first chamber 20 of the next cylinder 3, pushing the piston of the third cylinder 3 downward. The oil in the second chamber 21 passes through the throttle valve 17. At this time, the opening of the throttle valve 17 is 40%. Then, after the throttle valve 17 is closed by 60%, the second chamber 21 will be under pressure. For example, if the weight of the sample rod transported by the external load of the third cylinder 3 is 100kg, and the sequence valve is adjusted to 100kg overflow at this time, then after the first sequence valve 5 reaches the upper limit pressure, it opens and will throttle the excess 60% of the flow after throttling by the throttle valve 17, and together with the 60% of the flow after throttling by the throttle valve 17, it returns to the first pump 2. Thus, it can be known that the speeds of each cylinder 3 are: the first cylinder 3, the second cylinder 3, and the third cylinder 3 have different speeds.

[0052] The above description, based on the preferred embodiments of the present invention, provides inspiration. Those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification but must be determined according to the claims.

Claims

1. A control method for a multi-speed cylinder system, characterized by: The multi-speed oil cylinder system comprises an oil tank (1), a first pump (2) capable of being reversed, and a plurality of oil cylinders (3), the output ends of the first pump (2) in forward and reverse rotation are communicated with the oil tank (1) through first pipelines, the first pipelines between the output ends of the first pump (2) in forward and reverse rotation and the oil tank (1) are provided with liquid inlet check valves (4), the liquid inlet check valves (4) are used for preventing the backflow of oil into the oil tank (1), the forward rotation output end of the first pump (2) is communicated with the first cavities (20) of one end of the oil cylinders (3) through a second pipeline, the first cavities (20) and the second cavities (21) between adjacent two oil cylinders (3) are communicated through a third pipeline, the reverse rotation output end of the first pump (2) is communicated with the second cavities (21) of the other end of the oil cylinders (3) through a fourth pipeline, the first pump (2) and the plurality of oil cylinders (3) are connected in series with each other, the first and second sequence valves (5) and (6) are connected in parallel on the pipelines between the first cavities (20) and the second cavities (21) of the oil cylinders (3), and the first and second sequence valves (5) and (6) are reversely arranged with each other. The first proportional throttling assembly is arranged on the pipeline communicated with the first cavities (20) of the oil cylinders (3), the second proportional throttling assembly is arranged on the pipeline communicated with the second cavities (21) of the oil cylinders (3), the first sequence valve (5) is located between the second sequence valve (6) and the oil cylinders (3), and the first and second proportional throttling assemblies are located between the first sequence valve (5) and the oil cylinders (3). When the first pump (2) rotates in forward direction to supply oil, the oil enters the first cavities (20) of the oil cylinders (3) through the first proportional throttling assembly, the second proportional throttling assembly is used for controlling the oil return amount of the second cavities (21) and making the first cavities (20) generate pressure, When the first pump (2) rotates in reverse direction to supply oil, the oil enters the second cavities (21) of the oil cylinders (3) through the second proportional throttling assembly, the first proportional throttling assembly is used for controlling the oil return amount of the first cavities (20) and making the second cavities (21) generate pressure, Also include three-position four-way valve (7), two-position two-way valve (8) and second pump (9), the A oil port of three-position four-way valve (7) and the reverse output end between first pump (2) are communicated through the fourth pipeline, the B oil port of three-position four-way valve (7) and the A oil port of two-position two-way valve (8) are communicated, the P oil port of two-position two-way valve (8) and the positive rotation output end between first pump (2) are communicated through the fifth pipeline, the P oil port of three-position four-way valve (7) and the oil tank (1) are communicated through the sixth pipeline, the second pump (9) is arranged on the sixth pipeline, the T oil port of three-position four-way valve (7) and the oil tank (1) are communicated through the seventh pipeline, the second pipeline between the positive rotation output end of first pump (2) and the first cavity (20) of one end of oil cylinder (3) is provided with first hydraulic control check valve (10), the fourth pipeline between the reverse output end of first pump (2) and the second cavity (21) of the other end of oil cylinder (3) is provided with second hydraulic control check valve (11), first hydraulic control check valve (10), second hydraulic control check valve (11) and three-position four-way valve (7) are all signal connected with two-position two-way valve (8); The second pipeline between the positive rotation output end of first pump (2) and the first cavity (20) of one end of oil cylinder (3) is provided with first one-way high-pressure filtering assembly, the first one-way high-pressure filtering assembly is used for one-way delivery and filtering of oil when the first pump (2) is positively rotated, the fourth pipeline between the reverse output end of first pump (2) and the second cavity (21) of the other end of oil cylinder (3) is provided with second one-way high-pressure filtering assembly, the second one-way high-pressure filtering assembly is used for one-way delivery and filtering of oil when the first pump (2) is reversely rotated; The first one-way high-pressure filtering assembly and the second one-way high-pressure filtering assembly all include first one-way valve (12), second one-way valve (13) and filter (14), the first one-way valve (12) and the filter (14) are connected in series, the second one-way valve (13) is connected in parallel with the first one-way valve (12) and the filter (14), the first one-way valve (12) and the second one-way valve (13) are reversely arranged, the first one-way valve (12) is arranged corresponding to the first hydraulic control check valve (10) or the second hydraulic control check valve (11) on the pipeline thereof; The filter (14) is connected in parallel with pressure difference transmitter (15) at both ends thereof; The seventh pipeline between the T oil port of three-position four-way valve (7) and the oil tank (1) is provided with oil return filter (16); The first proportional throttling assembly and the second proportional throttling assembly all include throttle valve (17) and one-way valve (18), the throttle valve (17) and the one-way valve (18) are connected in parallel, the throttle valve (17) and the one-way valve (18) on the pipeline corresponding to the first cavity (20) and the second cavity (21) of oil cylinder (3) are all arranged in the same direction; The pipeline between the first cavity (20) and the second cavity (21) of oil cylinder (3) is connected in parallel with ball valve (19); The oil cylinder (3) is double-rod oil cylinder (3). The first pump (2) works to suck oil from the oil tank (1) through one of the inlet check valves (4) into the first pump (2), the first pump (2) supplies oil, and the first hydraulic control check valve (10) and the second hydraulic control check valve (11) are opened, the oil is filtered through one of the first one-way high-pressure filter assembly and the second one-way high-pressure filter assembly on the oil supply side, the filtered pressure oil enters one of the first cavity (20) and the second cavity (21) of the oil cylinder (3), the oil in the first cavity (20) and the second cavity (21) of the adjacent two oil cylinders (3) located in the first cavity (20) and the second cavity (21) of the previous oil cylinder (3) enters one of the first cavity (20) and the second cavity (21) of the next oil cylinder (3), and finally the oil is sucked into the first pump (2) for circulation and delivery, realizing the sequential action of the oil cylinders (3); When the action speed of the oil cylinders (3) needs to be adjusted, the throttle valve (17) on the pipeline connected to the first cavity (20) of the oil cylinder (3) and the throttle valve (17) on the pipeline connected to the second cavity (21) of the oil cylinder (3) are adjusted to the required action speed of the oil cylinders (3); When the oil pressure in the first part of the delivery direction exceeds the set pressure of the first sequence valve (5) or the second sequence valve (6), the first sequence valve (5) or the second sequence valve (6) with the same oil delivery direction of the first pump (2) is opened; When some of the oil cylinders (3) need to be actuated, the ball valve (19) corresponding to the other part of the oil cylinders (3) is opened; When the oil pressure provided by the first pump (2) is insufficient, the second pump (9) is opened, the three-position four-way valve (7) is switched between the left position and the right position, and the two-position two-way valve (8) is opened, realizing the oil supply and pressure compensation of the oil cylinder (3); When the oil in the oil tank (1) needs to be filtered, the second pump (9) is opened, the three-position four-way valve (7) is in the middle position, and the oil is filtered through the oil return filter (16).

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