Double-piston double-output-shaft oil hydraulic cylinder and hydraulic system

Abstract

The invention discloses a double-piston double-output-shaft oil hydraulic cylinder and a hydraulic system, and relates to the technical field of oil cylinders. The hydraulic cylinder comprises a cylinder barrel, an upper piston head and a lower piston head are coaxially arranged in the cylinder barrel, and an inner cavity is divided into an upper oil cavity, a middle oil cavity and a lower oil cavity which are sealed with one another. And the upper and lower piston heads are fixedly connected with upper and lower piston rods which penetrate through the cylinder barrel upwards and downwards respectively. An upper oil injection port and a lower oil injection port which are communicated with the upper oil cavity and the lower oil cavity are formed in the wall of the cylinder barrel; and a middle oil injection channel communicated with the middle oil cavity is formed in the upper piston rod. According to the structure, the inner cavity of the cylinder barrel is divided into the three independent oil cavities, and presetting of various strokes is achieved. And by controlling the positioning of the upper piston head, the lower piston rod can realize various telescopic motions with different strokes, so that the stroke adaptability and the application flexibility of the hydraulic cylinder are greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil cylinder, in particular to a double-piston double-output-shaft oil hydraulic cylinder and a hydraulic system. BACKGROUND

[0002] The double-rod hydraulic cylinder is a common actuator in the hydraulic system. As the name implies, the double-rod hydraulic cylinder is a hydraulic cylinder with piston rods on both sides of the piston. It is generally driven by bidirectional hydraulic pressure and can realize equal-speed reciprocating motion. The structure of the hydraulic cylinder can be basically divided into a cylinder barrel and a cylinder cover, a piston and a piston rod, a sealing device, a buffer device and the like. When the oil supply pressure and flow rate are constant, the conventional double-rod hydraulic cylinder is generally provided with only one piston, so that the motion speed and output in the left and right directions of the hydraulic cylinder are the same. This is because the force receiving areas on both sides of the piston are equal, and the double-rod enables the hydraulic cylinder to keep balance and stability during reciprocating motion. The lengths of the piston rods at both ends of the existing double-rod hydraulic cylinder are mostly fixed, which greatly limits the flexibility and adaptability of the hydraulic cylinder in different application scenarios. Since the overall stroke of the piston rod cannot be conveniently adjusted according to actual requirements, such a hydraulic cylinder is not capable of dealing with diversified work tasks, thereby reducing the overall practicality and versatility of the device. Therefore, the present application provides a double-rod hydraulic cylinder with adjustable stroke to meet the requirements. SUMMARY

[0003] The technical problem to be solved by the present application is to provide a double-piston double-output-shaft oil hydraulic cylinder and a hydraulic system to solve the problems of fixed stroke and poor flexibility in adapting to different working conditions of the existing double-rod hydraulic cylinder. The oil hydraulic cylinder can realize independent setting and combined control of multiple strokes, thereby improving the adjustability of the stroke and the adaptability to working conditions, and achieving compact structure and flexible control. To solve the above technical problems, the present application adopts the following technical scheme: A double-piston double-output-shaft oil hydraulic cylinder comprises a cylinder barrel, an upper piston head and a lower piston head are coaxially arranged in the cylinder barrel, the upper piston head and the lower piston head divide the inner cavity of the cylinder barrel into an upper oil chamber, a middle oil chamber and a lower oil chamber along the axial direction and the chambers are sealed from each other, an upper piston rod is fixedly connected to the upper piston head, the upper end of the upper piston rod extends out of one end of the cylinder barrel, a lower piston rod is fixedly connected to the lower piston head, the lower end of the lower piston rod extends out of the other end of the cylinder barrel, an upper oil inlet is formed in the wall of the cylinder barrel and communicates with the upper oil chamber, and a lower oil inlet is formed in the wall of the cylinder barrel and communicates with the lower oil chamber, a middle oil injection channel is arranged in the upper piston rod along the axial direction of the upper piston rod, one end of the middle oil injection channel communicates with the middle oil chamber, and the other end of the middle oil injection channel extends to the end of the upper piston rod.

[0004] Further, a radial through hole is formed in the connection between the upper piston rod and the upper piston, so that the middle oil injection channel communicates with the middle oil chamber.

[0005] Further, the upper piston rod serves as a positioning rod, oil is supplied to or returned from the upper oil cavity through the upper oil inlet, the movement of the upper piston is controlled, and the positioning function of the upper piston head is controlled.

[0006] By alternately supplying or returning oil to the middle oil inlet and the lower oil inlet, the lower piston head drives the lower piston rod to perform the downward and upward actions. Further, the side walls of the upper piston head and the lower piston head are respectively provided with sealing elements between the inner walls of the cylinder barrel, and the sealing elements are upper sealing rings installed on the outer periphery of the upper piston head and lower sealing rings installed on the outer periphery of the lower piston head.

[0008] Further, the lower end of the cylinder barrel is fixedly provided with a mounting seat, and at least two mounting holes are formed in the mounting seat.

[0009] Further, the mounting seat and the cylinder barrel are integrally welded and formed.

[0010] Further, the opening ends of the upper oil inlet, the lower oil inlet and the middle oil channel are provided with connectors for connecting external pipelines.

[0011] Further, displacement sensors are arranged on the side wall of the cylinder barrel, the upper piston rod or the lower piston rod, for detecting the real-time positions of the upper piston head and / or the lower piston head.

[0012] The application also provides a hydraulic system comprising the double-piston double-output-shaft oil hydraulic cylinder and a control valve group connected with the upper oil inlet, the lower oil inlet and the middle oil channel through oil lines.

[0013] The application has the following advantages: First, the inner cavity of the cylinder barrel is divided into three independent oil cavities, realizing the preset of multiple strokes. By controlling the oil inlet and outlet combination of different oil cavities, the upper and lower piston rods can realize various different stroke extension and contraction movements, greatly improving the stroke adaptability and application flexibility of the hydraulic cylinder.

[0014] Second, the oil inlet channel of the middle oil cavity is integrated in the upper piston rod (middle oil channel), without being opened in the side wall of the cylinder barrel, so that the flexibility of the upper piston head stroke is higher, the structure of the cylinder barrel is simplified, and the overall design is more compact and reliable.

[0015] Third, by controlling the oil inlet and outlet of the upper oil cavity, the upper piston is driven to move, thereby changing the volume of the middle oil cavity, and the movement distance of the lower piston head and the lower piston rod is accurately controlled, thereby expanding the application scenarios. BRIEF DESCRIPTION OF DRAWINGS

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings.

[0017] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0018] Figure 2 for Figure 1 A three-dimensional structural diagram from another angle.

[0019] Figure 3 This is a cross-sectional structural diagram of the present invention.

[0020] Explanation of reference numerals in the attached drawings: Cylinder 1, Upper oil inlet 101, Lower oil inlet 102, Upper oil chamber 103, Lower oil chamber 104, Middle oil chamber 105, Upper piston rod 2, Middle oil passage 201, Upper piston head 202, Lower piston rod 3, Lower piston head 301, Mounting seat 4, Mounting hole 401, Upper sealing ring 5, Lower sealing ring 6. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the embodiments of this invention will be described in detail below with reference to the accompanying drawings and specific examples. It should be noted that the following embodiments are only for explaining this invention and are not intended to limit the scope of protection of this invention. Example

[0022] like Figures 1 to 3 As shown, this embodiment provides a dual-piston dual-output shaft hydraulic cylinder, including a cylinder barrel 1, an upper piston rod 2, a lower piston rod 3, an upper piston head 202, a lower piston head 301, and a mounting base 4.

[0023] The cylinder 1 has a cylindrical structure, inside which an upper piston head 202 and a lower piston head 301 are coaxially mounted. Three mutually sealed oil chambers are formed between the upper piston head 202 and the lower piston head 301, and between both of them and the two ends of the cylinder 1: an upper oil chamber 103 located above the upper piston head 202, a middle oil chamber 105 located between the upper piston head 202 and the lower piston head 301, and a lower oil chamber 104 located below the lower piston head 301. An upper sealing ring 5 is installed on the outer circumference of the upper piston head 202, and a lower sealing ring 6 is installed on the outer circumference of the lower piston head 301, ensuring the sealing between the oil chambers.

[0024] The upper piston rod 2 is fixedly connected to the upper piston head 202 and extends upward through the upper end of the cylinder 1. An axially machined oil inlet channel 201 is formed inside the upper piston rod 2. This channel has a radial through hole at the connection between the upper piston rod 2 and the upper piston head 202, thus communicating with the intermediate oil chamber 105. A connector for connecting an external oil pipe is provided at the upper end of the upper piston rod 2.

[0025] The lower piston rod 3 is fixedly connected to the lower piston head 301 and extends downward through the lower end of the cylinder 1. The side wall of the cylinder 1 is provided with an upper oil inlet 101 and a lower oil inlet 102, which are respectively connected to the upper oil chamber 103 and the lower oil chamber 104. Each oil inlet is equipped with a standard hydraulic connector.

[0026] A mounting base 4 is welded and fixed to the lower end of the cylinder barrel 1. The mounting base 4 has multiple mounting holes 401 to facilitate the fixed installation of the hydraulic cylinder on the equipment.

[0027] Description of the working process of this invention: This hydraulic cylinder can achieve various stroke combinations of the upper and lower piston rods by independently controlling the oil inlet and outlet of its three oil chambers. The specific control method is as follows: Upper piston rod positioning function: By supplying or returning oil to the upper oil chamber 103 through the upper oil inlet 101, the upper piston head 202 can be driven to move axially along the cylinder 1, thereby changing its position. Once the position of the upper piston head 202 is fixed, the initial volume of the middle oil chamber 105 is determined, which in turn limits the range of motion of the lower piston head 301.

[0028] Lower piston rod stroke control: The movement of the lower piston rod 3 is controlled by the oil pressure in the middle oil chamber 105 and the lower oil chamber 104: Downward stroke: Oil is supplied to the middle oil passage 201, causing oil to enter the middle oil chamber 105, while oil returns to the lower oil chamber 104. The lower piston head 301 moves downward, pushing the lower piston rod 3 to extend.

[0029] Rising stroke: Oil is supplied to the lower oil inlet 102, causing oil to enter the lower oil chamber 104, while oil returns from the middle oil chamber 105. The lower piston head 301 moves upward, driving the lower piston rod 3 to retract.

[0030] Variable travel principle: By adjusting the position of the upper piston head 202, the initial length of the middle oil chamber 105 can be changed. When the length of the middle oil chamber 105 is larger, the extension stroke of the lower piston rod 3 is shorter; conversely, when the length of the middle oil chamber 105 is smaller, the extension stroke of the lower piston rod 3 increases accordingly. This achieves multi-stage adjustable stroke of the lower piston rod 3. Example

[0031] Based on Example 1, this example further provides a hydraulic system, which includes a dual-piston dual-output shaft hydraulic cylinder as described in Example 1, and an intelligent control valve group connected thereto.

[0032] The intelligent control valve assembly is connected to the upper oil inlet 101, the lower oil inlet 102, and the middle oil passage 201 at the end of the upper piston rod 2 via oil circuits. The valve assembly can be a proportional valve or a servo valve and accepts commands from an external controller to achieve precise and coordinated control of the oil pressure in the upper, middle, and lower oil chambers.

[0033] To further improve control accuracy, a displacement sensor (not shown in the figure) is installed on the side wall of cylinder 1 to detect the position of the upper piston head 202 and / or the lower piston head 301 in real time and feed the signal back to the controller to form a closed-loop control.

[0034] This system is suitable for applications requiring multi-stage strokes and multi-position outputs, such as presses, injection molding machines, and testing machines. Through program settings, different combinations of upper piston head positioning and lower piston movement can be activated with a single click, achieving flexible and programmable stroke outputs and significantly improving the equipment's process adaptability and automation level.

[0035] Further explanation regarding the control system: The control valve assembly, controller, and displacement sensor included in the hydraulic system are all well-known components in the fields of hydraulics and electro-hydraulic control. For example, the control valve assembly can use a combination of three-way proportional valves or servo valves, which are conventional in the art, to achieve independent and continuous control of each oil circuit; the controller can be a programmable logic controller (PLC) or an industrial computer; and the displacement sensor can be a magnetostrictive or draw-wire sensor. The electrical connections and signal interactions between these components (such as the controller sending commands to the valve assembly and the sensor feeding back signals to the controller) also fall under the standard closed-loop control technology in the art.

[0036] The key to this invention lies in combining the aforementioned known intelligent control system with the unique double-piston three-chamber hydraulic cylinder structure of this invention, thereby realizing a novel and non-obvious control method and workflow: Upper piston positioning stage: The system drives the upper piston head 202 to move by controlling the upper oil chamber 103 or returning oil from the middle through the control valve group. The controller receives the upper piston head position signal fed back by the displacement sensor and precisely positions it at any preset position in the cylinder through closed-loop control, thereby fixing the initial volume of the middle oil chamber 105.

[0037] Lower piston stroke execution stage: With the upper piston head position fixed, the system alternately supplies and returns oil to the intermediate oil chamber 105 and the lower oil chamber 104 through the control valve group, driving the lower piston rod 3 to perform extension (depress) or retraction (rise) actions. Since the initial volume of the intermediate oil chamber has been determined by the position of the upper piston head, the maximum effective stroke of the lower piston rod 3 is also determined and changes accordingly.

[0038] Coordinated control logic: The core of the entire system's control logic lies in "positioning first, then execution." The controller can store multiple sets of preset parameters (upper piston head position X, lower piston rod target stroke Y). By calling different parameter sets, the same hydraulic cylinder can automatically achieve multiple different output strokes without any mechanical structural adjustments.

[0039] Through the above methods, this invention utilizes mature closed-loop electro-hydraulic control technology to endow the integrated dual-output shaft cylinder with unprecedented stroke programmability and flexible output capability. Those skilled in the art, upon learning of the dual-piston three-chamber cylinder structure described in this invention, can easily select and connect corresponding known control components to achieve all the functions described in this invention. Example

[0040] This embodiment illustrates the application of the above-mentioned hydraulic cylinder in a multi-station stamping equipment: The equipment has three different stamping height requirements. During installation, the hydraulic cylinder is fixed to the frame via the mounting base 4, and the lower piston rod 3 is connected to the stamping head.

[0041] When shallow stamping is required, the upper piston head 202 is controlled to move to the upper part of the cylinder and lock in the position; then the lower piston rod 3 is controlled to perform short-stroke stamping.

[0042] When medium-depth stamping is required, adjust the upper piston head 202 to the middle of the cylinder, and then drive the lower piston rod 3 to perform medium-stroke movement.

[0043] When deep drawing is required, the upper piston head 202 is positioned in the lower part of the cylinder to allow the lower piston rod 3 to obtain the maximum stroke.

[0044] The entire process can be automatically switched via the hydraulic system, without the need for mechanical adjustment or replacement of the oil cylinder, which greatly improves the production efficiency and flexibility of the equipment.

[0045] In summary, this invention, through its unique dual-piston, three-chamber design, integrates stroke adjustment into the cylinder structure. Combined with the oil passage integrated into the piston rod, it achieves the advantages of compact structure, flexible control, and variable stroke, effectively expanding the application capabilities of hydraulic cylinders under complex working conditions.

[0046] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A double piston double output shaft oil hydraulic cylinder comprising a cylinder barrel (1), characterized in that, The cylinder (1) is coaxially provided with an upper piston head (202) and a lower piston head (301), the upper piston head (202) and the lower piston head (301) divide the inner cavity of the cylinder (1) into an upper oil cavity (103), a middle oil cavity (105) and a lower oil cavity (104) along the axial direction and the upper piston head (202) and the lower piston head (301) are sealed from each other; the upper piston head (202) is fixedly connected with an upper piston rod (2), the upper end of the upper piston rod (2) passes out of one end of the cylinder (1) upward; the lower piston head (301) is fixedly connected with a lower piston rod (3), the lower end of the lower piston rod (3) passes out of the other end of the cylinder (1) downward; the cylinder wall of the cylinder (1) is provided with an upper oil inlet (101) communicated with the upper oil cavity (103) and a lower oil inlet (102) communicated with the lower oil cavity (104); the middle oil channel (201) is provided in the upper piston rod (2) along the axial direction thereof, one end of the middle oil channel (201) is communicated with the middle oil cavity (105) and the other end of the middle oil channel (201) extends to the end of the upper piston rod (2).

2. The dual piston dual output shaft hydraulic cylinder of claim 1, wherein, The upper piston rod (2) is provided with a radial through hole at the connection position of the upper piston rod (2) and the upper piston head (202), so that the middle oil channel (201) is communicated with the middle oil cavity (105).

3. Double piston double output shaft oil hydraulic cylinder according to claim 1 or 2, characterized in that, The upper piston rod (2) is used as a positioning rod, oil is supplied or returned to the upper oil cavity (103) through the upper oil inlet (101), the movement of the upper piston is controlled, and the positioning function of the upper piston head (202) is realized.

4. The dual piston dual output shaft hydraulic cylinder of claim 1, wherein, By alternately supplying or returning oil to the middle oil inlet (201) and the lower oil inlet (102), the lower piston head (301) drives the lower piston rod (3) to perform the actions of pressing downward and rising.

5. The dual piston dual output shaft oil hydraulic cylinder of claim 1, wherein, The side walls of the upper piston head (202) and the lower piston head (301) are respectively provided with sealing elements between the side walls of the upper piston head (202) and the lower piston head (301) and the inner wall of the cylinder (1), the sealing elements are an upper sealing ring (5) installed on the outer periphery of the upper piston head (202) and a lower sealing ring (6) installed on the outer periphery of the lower piston head (301).

6. The dual piston dual output shaft oil hydraulic cylinder of claim 1, wherein, The lower end of the cylinder (1) is fixedly provided with a mounting seat (4), at least two mounting holes (401) are formed in the mounting seat (4).

7. The dual piston dual output shaft hydraulic cylinder of claim 6, wherein, The mounting seat (4) and the cylinder (1) are integrally welded and formed.

8. The dual piston dual output shaft oil hydraulic cylinder of claim 1, wherein, The opening ends of the upper oil inlet (101), the lower oil inlet (102) and the middle oil channel (201) are respectively provided with connectors for connecting external pipelines.

9. The dual piston dual output shaft oil hydraulic cylinder of claim 1, wherein, A displacement sensor is arranged on the side wall of the cylinder (1), the upper piston rod (2) or the lower piston rod (3) and is used for detecting the real-time position of the upper piston head (202) and / or the lower piston head (301).

10. A hydraulic system characterized by, The double-piston double-output-shaft oil hydraulic cylinder comprises the double-piston double-output-shaft oil hydraulic cylinder and an intelligent control valve group connected with the upper oil inlet (101), the lower oil inlet (102) and the middle oil channel (201) through oil lines.

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