Single hydraulic pump high synchronous stress gradient loading press

Abstract

The present application relates to the technical field of press machine, in particular to a single hydraulic pump strong synchronous stress gradient loading press machine, which comprises a plunger pump and a matched motor fixedly connected with the plunger pump. The present application provides a single power source by the plunger pump and the matched motor, and realizes multi-stage conversion of hydraulic pressure by combining four different multiple transformers in the pressure conversion mechanism, so as to generate four groups of hydraulic oil output with different pressures for building a stress gradient environment, which realizes high integration and optimization, avoids the use of multiple independent hydraulic pumps and their control systems in the traditional multi-cylinder loading system, greatly simplifies the complexity of the overall equipment, and reduces the manufacturing and maintenance costs. At the same time, since a single power source is adopted for driving, the response consistency of the hydraulic system is stronger, which avoids the synchronization problem caused by the response delay or load coupling of each cylinder hydraulic system in the multi-cylinder loading process, thereby improving the stability and control precision of the loading process.

Description

Technical Field

[0001] This invention relates to the field of press technology, and more specifically, to a single hydraulic pump strong synchronous stress gradient loading press. Background Technology

[0002] The single hydraulic pump strong synchronous stress gradient loading press is a special equipment used in the fields of material testing and component forming. Its core design lies in achieving strong synchronous loading of the workpiece through a single hydraulic pump and accurately applying stress gradient to meet specific mechanical property testing or processing needs.

[0003] The disturbance caused by tunnel excavation disrupts the initial stress equilibrium of the original rock mass, leading to a redistribution of rock stress and the generation of a stress gradient in space. This can induce tunnel disasters. During this process, the stress gradient is a key factor controlling tunnel stability, and its dynamic evolution directly affects surrounding rock deformation, fracture propagation, and the final instability mode. Therefore, accurately simulating the stress gradient loading process under laboratory conditions is of great significance for revealing the mechanism of tunnel surrounding rock disasters and optimizing support design.

[0004] Currently, multi-hydraulic pump collaborative loading systems are mainly used to simulate stress gradient environments. These devices typically employ multiple independently controlled cylinders to apply differential loads to different locations on the specimen to construct a spatial stress gradient. However, this method has the following significant drawbacks: (1) System complexity and high cost: Multi-cylinder loading requires an independent hydraulic control system and synchronization coordination module. The equipment structure is complex, the manufacturing cost is high, and the maintenance is difficult, making it difficult to promote in ordinary laboratories.

[0005] (2) Insufficient synchronous control accuracy: When multiple cylinders are loaded in coordination, the response delay and load coupling effect of the hydraulic system can easily lead to asynchronous stress gradient loading, affecting the accuracy of experimental data, especially in the dynamic gradient change stage.

[0006] (3) Low space utilization and limited experimental setup: Traditional multi-cylinder loading systems require multiple independent hydraulic actuators (cylinders or actuators) and supporting frames, resulting in a large overall structure that occupies a lot of laboratory space. The space occupation problem of existing devices is particularly prominent when they need to be used in conjunction with other testing systems (such as acoustic emission monitoring, CT scanning, etc.) during experiments, making it difficult to meet the needs of complex experimental environments.

[0007] In view of this, we propose a single hydraulic pump strong synchronous stress gradient loading press. Summary of the Invention

[0008] The purpose of this invention is to provide a single hydraulic pump strong synchronous stress gradient loading press to solve the problems mentioned in the background art, such as the need for independent hydraulic control and synchronization modules, complex structure, high cost, difficult maintenance, and difficulty in promotion; asynchronous stress gradient loading due to response delay and load coupling during collaborative loading, affecting data accuracy; and large structure occupying space and limiting its use in conjunction with other testing systems.

[0009] To achieve the above objectives, the present invention provides a single hydraulic pump strong synchronous stress gradient loading press, including a piston pump and a matching motor fixedly connected thereto. The transformer mechanism includes four transformers with different multiples. Each transformer includes: a sealing force transmission rod with a sealing cylinder sleeve of different cross-sectional area connected to both ends; an initial pressure hydraulic oil chamber and a transformed hydraulic oil chamber slidably connected to both ends of the sealing force transmission rods. By designing different area ratios for the sealing cylinder liners, the initial hydraulic pressure can be controlled: when the ratio of the area of ​​the sealing cylinder liner in the initial pressure hydraulic oil chamber to the area of ​​the sealing cylinder liner in the hydraulic oil chamber after pressure change is greater than 1, the system achieves pressure increase and pressure change; when the ratio is less than 1, the system achieves pressure decrease and pressure change.

[0010] The beneficial effects of this invention are: 1. In this invention, only a single plunger pump provides power, and four transformers with different ratios are used to complete the pressure conversion. There is no need to equip multiple cylinders with independent hydraulic control systems and synchronization coordination modules, which greatly simplifies the equipment structure, reduces manufacturing costs, and reduces the effort and cost required for maintenance. This makes the equipment easier to promote and use in ordinary laboratories. The pressure change is precisely controlled by the area ratio of the sealing cylinder sleeves at both ends of the transformer, so that the pressure transmission is direct and stable. This avoids the synchronization problem caused by the response delay of the hydraulic system and the load coupling effect when multiple cylinders are loaded together. Especially in the dynamic gradient change stage, it can effectively ensure the synchronization of stress gradient loading and improve the accuracy of experimental data. The overall structure eliminates the need for multiple independent hydraulic actuators and supporting frames required by traditional multi-cylinder systems, making it more compact and significantly reducing the laboratory space required. When used in conjunction with other testing systems such as acoustic emission monitoring and CT scanning, it can better adapt to complex experimental environments and reduce the limitations of space occupation on experimental setup. 2. In this invention, in the transformer mechanism, the initial pressure hydraulic oil chamber and the transformed hydraulic oil chamber are connected by a threaded connecting ring. This connection method facilitates the quick assembly and disassembly of the two, provides convenience for equipment maintenance and component replacement, and at the same time ensures the sealing and stability of the connection, reducing the possibility of hydraulic oil leakage. The air inlet and outlet ports on one side of the initial pressure hydraulic oil chamber pass through the threaded connecting ring, which can effectively expel air from the chamber and prevent residual air from interfering with the pressure transmission of the hydraulic system. This ensures that the pressure loading process is stable and accurate. The four transformers achieve different pressure conversion through their own structure, and then transmit the pressure to the corresponding jacks, so that the jacks can apply different pressures to the rock sample, accurately construct the stress gradient, and meet the experimental needs for simulating different stress environments.

[0011] As a further improvement to this technical solution, the outer wall of the initial pressure hydraulic oil chamber is threaded with a threaded connecting ring, and one end of the threaded connecting ring is threadedly connected to the outer wall of the transformed hydraulic oil chamber. The initial pressure hydraulic oil chamber and the transformed hydraulic oil chamber are used to store hydraulic oil. One side of the initial pressure hydraulic oil chamber is connected to an inlet and outlet port, and the inlet and outlet port passes through the threaded connecting ring. The top of each transformer is connected to a jack inlet pipe, and a first five-way connector is provided below the four transformers. The top of the first five-way connector is connected to the bottom of the four transformers.

[0012] The beneficial effect of adopting the above-mentioned further scheme is that by using the precision mechanical conversion principle of hydraulic transformer (P0×S0=P1×S1), the same initial pressure is accurately distributed to the four sets of output terminals, so that the pressure value error of each loading jack is controlled within a high precision range; at the same time, by utilizing the rapid transmission characteristics of hydraulic oil in a single circuit, the millisecond-level synchronous response of each jack is achieved, which completely solves the problem of loading asynchrony caused by time delay in traditional systems.

[0013] As a further improvement to this technical solution, a loading mechanism is provided on one side of the transformer mechanism, which includes: four jacks that are connected to the output ends of the four jack inlet pipes, an upper crossbeam fixedly installed on the top of the four jacks, a column fixedly connected to the bottom of the upper crossbeam, a lower crossbeam installed at the bottom of the column, a loading plate assembled at the bottom of the four jacks, a pad fixedly installed on the top of the lower crossbeam, a base fixedly connected to the bottom surface of the lower crossbeam, and the output ends of the jacks connected to the jack return pipes.

[0014] The beneficial effect of adopting the above-mentioned further solution is that the innovative integrated hydraulic power source design breaks through the limitation of traditional rock stress gradient loading presses that require each loading unit to be equipped with an independent hydraulic pump. Through the core structure of the transformer module, only one set of hydraulic power components such as piston pump and motor is needed. Four hydraulic transformers with different transformation ratios can be used to convert the initial hydraulic pressure into four sets of independent adjustable pressure outputs to meet the multi-stress gradient loading requirements of the loading module. Compared with the traditional solution, this design reduces the power hardware configuration by about 3 / 4 and significantly reduces the procurement cost.

[0015] As a further improvement to this technical solution, an oil tank is fixedly installed at the bottom of the matching motor. An overflow return oil pipe and a suction oil pipe are connected through the top of the oil tank, and the top of the suction oil pipe is connected to a plunger pump. An overflow valve is fixedly installed on the overflow return oil pipe, and the overflow return oil pipe is connected to a first high-pressure pipe. A second high-pressure pipe is also connected to the oil tank. An electromagnetic reversing valve is installed on both the first and second high-pressure pipes to control the flow direction of the hydraulic oil. The first high-pressure pipe is connected through to a first five-way connector, and one end of the second high-pressure pipe is connected to a second five-way connector. The remaining interfaces of the second five-way connector are connected to the jack return oil pipe.

[0016] The beneficial effect of adopting the above-mentioned further solution is that pressure conversion is achieved based on a single hydraulic power source, which fundamentally solves the accuracy error caused by the performance differences of multiple pumps in traditional split power systems.

[0017] The difference between this invention and the prior art: 1. This single-hydraulic pump strong synchronous stress gradient loading press provides a single power source through a piston pump and a matching motor. Combined with four transformers of different multiples in the transformer mechanism, it realizes multi-stage conversion of hydraulic pressure, thereby generating four sets of hydraulic oil outputs with different pressures to construct a stress gradient environment. It achieves high integration and optimization, avoiding the use of multiple independent hydraulic pumps and their control systems in traditional multi-cylinder loading systems, greatly simplifying the complexity of the overall equipment and reducing manufacturing and maintenance costs. Meanwhile, due to the use of a single power source, the hydraulic system has stronger response consistency, avoiding the synchronization problems caused by the response delay or load coupling of each cylinder's hydraulic system during multi-cylinder loading. This improves the stability and control accuracy of the loading process. Especially during the dynamic stress gradient change stage, the system can more accurately achieve the expected stress distribution, ensuring the authenticity and reliability of the experimental data.

[0018] 2. In this single hydraulic pump strong synchronous stress gradient loading press, each transformer in the transformer mechanism is connected to a sealed force transmission rod through a sealed cylinder sleeve with different cross-sectional areas at both ends, and is slidably connected to the initial pressure hydraulic oil chamber and the transformed hydraulic oil chamber respectively, realizing the pressure conversion function based on the area ratio. This pressure conversion method based on Pascal's principle makes pressure regulation not dependent on a complex electronic control system, but directly completed through mechanical structure design, further improving the stability and controllability of the system. When the ratio of the sealed cylinder liner area between the initial pressure hydraulic oil chamber and the transformed hydraulic oil chamber is greater than 1, the system achieves a pressure boosting effect; when the ratio is less than 1, it achieves a pressure reduction effect. This flexible pressure transformation capability allows the system to adapt to various stress gradient experimental requirements without replacing the power unit or control system. Pressure regulation can be achieved simply by adjusting the structural parameters of the transformer.

[0019] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure assembly of the present invention; Figure 2 This is a cross-sectional view of the internal structure of the transformer of the present invention; Figure 3 This is a cross-sectional view of the transformer mechanism of the present invention; Figure 4 This is a cross-sectional view of the loading mechanism of the present invention; Figure 5 This is a schematic diagram of the overflow return oil pipeline, high-pressure pipeline, and oil tank of the present invention; Figure 6 This is a cross-sectional view of the overall structure of the present invention.

[0021] The meanings of the labels in the diagram are as follows: 100. Piston pump; 101. Matching motor; 102. Overflow return oil line; 103. First high-pressure pipe; 1031. Second high-pressure pipe; 104. Solenoid directional valve; 105. Oil tank; 200. Transformer mechanism; 210. Transformer; 211. Initial pressure hydraulic oil chamber; 212. Threaded connecting ring; 213. Hydraulic oil chamber after transformation; 214. Sealed force transmission rod; 220. First five-way connector; 2201. Second five-way connector; 300. Loading mechanism; 301. Upper crossbeam; 302. Lower crossbeam; 303. Column; 304. Jack; 305. Pad; 306. Loading plate; 400. Jack inlet pipe; 401. Jack return pipe. Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The present invention provides the following preferred embodiments. Please see Figure 1 - Figure 6 As shown, this embodiment provides a single hydraulic pump strong synchronous stress gradient loading press, including a piston pump 100 and a matching motor 101 fixedly connected thereto; The transformer mechanism 200 includes four transformers 210 with different multiples. Each transformer 210 includes: a sealing force transmission rod 214 with sealing cylinder sleeves of different cross-sectional areas connected to both ends; an initial pressure hydraulic oil chamber 211 and a transformed hydraulic oil chamber 213 slidably connected to both ends of the sealing force transmission rods 214. By designing different area ratios of the sealing cylinder liners, the initial hydraulic pressure can be controlled: when the ratio of the area of ​​the sealing cylinder liner in the initial pressure hydraulic oil chamber 211 to the area of ​​the sealing cylinder liner in the pressure-changed hydraulic oil chamber 213 is greater than 1, the system achieves pressure increase and pressure change; when the ratio is less than 1, the system achieves pressure decrease and pressure change.

[0024] Therefore, based on the above features, the improvements of the present invention will be described in detail: Considering that current simulations of stress gradient environments mainly rely on multi-hydraulic pump collaborative loading systems, these devices typically employ multiple independently controlled cylinders to construct spatial stress gradients by applying differential loads to different locations on the sample. However, this system has significant drawbacks: First, multi-cylinder loading requires an independent hydraulic control system and synchronization module, which not only complicates the equipment structure but also significantly increases manufacturing costs and maintenance difficulty, making it difficult to promote its application in ordinary laboratories. Second, during multi-cylinder collaborative loading, the response delay of the hydraulic system and the load coupling effect can easily cause asynchronous stress gradient loading, thus affecting the accuracy of experimental data, especially during dynamic gradient change phases. Third, traditional multi-cylinder loading systems require multiple independent hydraulic actuators such as cylinders or actuators and supporting support frames, resulting in a large overall structure that occupies a significant amount of laboratory space. When experiments require integration with other testing systems such as acoustic emission monitoring and CT scanning, the space occupancy problem of existing devices becomes particularly pronounced, making it difficult to meet the needs of complex experimental environments. Therefore, in terms of structural complexity and cost, this system does not require multiple independent hydraulic pumps and supporting control systems. It only relies on a single plunger pump 100 and a matching motor 101 to provide power. Combined with four transformers 210 of different multiples in the transformer mechanism 200, stress gradient loading can be achieved. Each transformer 210 is connected to the two sealed force transmission rods 214 through sealed cylinder sleeves with different cross-sectional areas at both ends. It completes pressure conversion in conjunction with the initial pressure hydraulic oil chamber 211 and the transformed hydraulic oil chamber 213. This eliminates the need for independent hydraulic control systems and synchronization coordination modules required for multiple cylinders, simplifies the equipment structure, reduces manufacturing costs and maintenance difficulty, and makes it easier to promote in ordinary laboratories. In terms of synchronization control accuracy, the system is based on a single power source drive and achieves pressure regulation through the area ratio design of the sealed cylinder sleeve of transformer 210. This avoids synchronization problems caused by hydraulic system response delay and load coupling effect when multiple cylinders are loaded together. The pressure conversion between the initial pressure hydraulic oil chamber 211 and the pressure-transformed hydraulic oil chamber 213 is directly determined by the area ratio of the sealed cylinder sleeve, making pressure transmission more direct and stable. Especially in the dynamic gradient change stage, it can reduce the situation of asynchronous stress gradient loading and improve the accuracy of experimental data. In terms of space utilization, the system abandons the multiple independent hydraulic actuators and supporting frames of the traditional multi-cylinder loading system, resulting in a more compact overall structure. The transformer mechanism 200 achieves pressure gradient construction through the integrated transformer 210, which greatly reduces the space occupied. When it needs to be used in conjunction with other testing systems such as acoustic emission monitoring and CT scanning, it can better adapt to complex experimental environments and reduce the space occupation restrictions on experimental layout. Based on the above, the specific structure will be disclosed in detail: To convert the hydraulic pressure generated by the plunger pump 100 into four different sets of hydraulic pressure, the transformer mechanism 200 is disclosed in detail, as follows: Figure 2 and Figure 3 As shown, the outer wall of the initial pressure hydraulic oil chamber 211 is threadedly connected to a threaded connecting ring 212, and one end of the threaded connecting ring 212 is threadedly connected to the outer wall of the transformed hydraulic oil chamber 213. The initial pressure hydraulic oil chamber 211 and the transformed hydraulic oil chamber 213 are used to store hydraulic oil. One side of the initial pressure hydraulic oil chamber 211 is connected to an air inlet and outlet hole, which passes through the threaded connecting ring 212. The outer wall of the initial pressure hydraulic oil chamber 211 and the outer wall of the transformed hydraulic oil chamber 213 are threadedly connected by the threaded connecting ring 212. This connection method not only facilitates the quick assembly and disassembly of the initial pressure hydraulic oil chamber 211 and the transformed hydraulic oil chamber 213, which is beneficial for equipment maintenance and component replacement, but also ensures the sealing and stability of the connection between the two, reducing the risk of hydraulic oil leakage. The air inlet and outlet hole on one side of the initial pressure hydraulic oil chamber 211 passes through the threaded connecting ring 212, which can effectively discharge air in the chamber, avoid interference of residual air on the pressure transmission of the hydraulic system, and ensure the stability and accuracy of pressure loading.

[0025] Specifically, such as Figure 3 As shown, each transformer 210 has a jack oil inlet pipe 400 connected through to its top, and a first five-way connector 220 is provided below the four transformers 210. The first five-way connector 220 includes a first five-way connector 220 and a second five-way connector 2201. The top of the first five-way connector 220 is connected through to the bottom of the four transformers 210. The hydraulic oil inlet pipe 400, which is connected to the top of the four transformers 210, and the first five-way connector 220 below, are connected to the bottom of the four transformers 210. This enables centralized distribution and circulation of hydraulic oil, allowing the hydraulic energy provided by the single piston pump 100 to be accurately and efficiently transmitted to each transformer 210. This ensures the consistency of power supply when multiple transformers 210 are working, further enhances the integration of the system, improves the stability of the hydraulic system, and also creates more favorable conditions for the joint use of the equipment with other testing systems, better meeting the needs of complex experimental environments.

[0026] Furthermore, to achieve the application of four different pressures to the rock sample using the jack 304, the loading mechanism 300 is disclosed in detail, specifically as follows: Figure 4 As shown, a loading mechanism 300 is provided on one side of the transformer mechanism 200, which includes: four jacks 304 that are connected to the output end of the four jack oil inlet pipes 400, an upper crossbeam 301 fixedly installed on the top of the four jacks 304, a column 303 fixedly connected to the bottom of the upper crossbeam 301, and a lower crossbeam 302 installed at the bottom of the column 303. Therefore, the four different pressures of hydraulic oil after the pressure change are introduced into the four jacks 304 through the jack inlet pipe 400. At this time, the jacks 304 generate four different pressures and apply them to the rock sample, thereby forming a gradient loading. After the loading test is completed, the electromagnetic reversing valve 104 is adjusted, and the high pressure oil enters the jacks 304 through the return oil pipe, pushing the hydraulic oil back and realizing the retraction of the jacks 304. After being transformed, hydraulic oil with four different pressures enters four jacks 304 through the jack inlet pipe 400, generating four different pressures which are then applied to the rock sample. This accurately constructs a stress gradient environment that meets experimental requirements, realistically simulating the non-uniform stress state experienced by rock mass in scenarios such as tunnel excavation. It provides reliable loading conditions for studying the deformation, crack propagation, and instability of rock samples under gradient stress, helping to reveal related disaster mechanisms. After the loading test, by adjusting the electromagnetic reversing valve 104, high-pressure oil enters the jacks 304 through the return pipe and pushes the hydraulic oil back, causing the jacks 304 to retract. This facilitates the quick removal of the rock sample after the test, providing convenience for the preparation of the next test, and also allows the jacks 304 to return to their initial state, ensuring the accuracy and reliability of subsequent loading tests. At the same time, this design allows the hydraulic oil to be recycled, improving the operating efficiency of the hydraulic system and further enhancing the flexibility and practicality of the equipment operation.

[0027] The bottom of each of the four jacks 304 is equipped with a loading plate 306, and the top of the lower crossbeam 302 is fixedly installed with a pad 305. The bottom surface of the lower crossbeam 302 is fixedly connected to a base. The output end of the jacks 304 is connected to the jack return oil pipe 401. The loading plates 306 at the bottom of the four jacks 304 and the fixed pad 305 at the top of the lower crossbeam 302 cooperate with each other to provide a stable loading contact surface for the sample, which can make the loading force more evenly transmitted to the sample, reduce local stress concentration caused by poor contact, protect the sample and ensure the reliability of experimental data. The output end of the jacks 304 is connected to the jack return oil pipe, which facilitates the recovery and recycling of hydraulic oil, improves the efficiency of the hydraulic system, and also facilitates flexible control of the loading process, making it convenient to adjust the magnitude and rhythm of the loading force according to experimental needs.

[0028] Then, to achieve a stable and controllable load for the transformer mechanism 200, specifically as follows: Figure 5 and Figure 6 As shown, an oil tank 105 is fixedly installed at the bottom of the matching motor 101. An overflow return oil pipe 102 and an oil suction pipe are connected through the top of the oil tank 105, and the top of the oil suction pipe is connected to the plunger pump 100. An overflow valve is fixedly installed on the overflow return line 102, and the overflow return line 102 is connected to the first high pressure line 103. The oil tank 105 is also connected to the second high pressure line 1031. The first high pressure line 103 and the second high pressure line 1031 are both equipped with a solenoid directional valve 104 to control the flow direction of the hydraulic oil. The first high-pressure pipe 103 is connected to the first five-way connector 220, and one end of the second high-pressure pipe 1031 is connected to the second five-way connector 2201. The other interfaces of the second five-way connector 2201 are connected to the jack return oil pipe 401. Therefore, after being powered on, the matching motor 101 rotates and outputs mechanical energy. The matching motor 101 drives the swashplate or eccentric wheel of the plunger pump 100 to rotate, causing the plunger to reciprocate in the cylinder. Hydraulic oil enters the pump body from the oil tank 105 through the oil suction pipe, forming an oil suction and oil pressure process. The high-pressure oil generated enters the first high-pressure pipe 103 or the second high-pressure pipe 1031 depending on the electromagnetic control valve. If the pressure reaches the relief valve's set value, the valve opens, and excess oil flows back to the oil tank 105 to prevent overpressure damage to components. If the system pressure does not exceed the limit, the relief valve closes, and all oil is used to drive the actuator. According to the control signal, the electromagnet pushes the valve core to move, changing the direction of the oil circuit. Pressure oil is introduced through port A and oil is returned through port B - the jack 304 extends outward for loading, and pressure oil is introduced through port B and oil is returned through port A - the jack 304 retracts for unloading. The first high-pressure pipe 103 is connected to the first five-way connector 220, and the second high-pressure pipe 1031 is connected to one end of the second five-way connector 2201, while the other end of the second five-way connector 2201 is connected to the return oil pipe of the jack 304. This pipeline connection method realizes the orderly flow and distribution of hydraulic oil in the system, ensuring that the high-pressure oil can be accurately delivered to the corresponding components, ensuring the coordinated work of the transformer mechanism 200 and the loading mechanism 300, further improving the coordination and reliability of the entire system operation, and also providing convenience for system maintenance and repair, which helps to improve the overall service life and operating efficiency of the equipment.

[0029] The specific steps to achieve precise application of stress gradient are as follows: Let the initial hydraulic pressure be P0, the transformed hydraulic pressure be P1, the area of ​​the sealing cylinder liner in the initial hydraulic oil chamber be S0, and the area of ​​the sealing cylinder liner in the transformed hydraulic oil chamber 213 be S1. According to the mechanical formula: P0 × S0 = P1 × S1 The derivation yields: P1 = P0 × S0 / S1 Therefore, by setting different area ratios S0 / S1 for the sealed cylinder liners, variable pressure control of the initial hydraulic pressure P0 can be achieved. When S0 / S1 > 1, the system achieves pressure increase and change; when S0 / S1 < 1, it achieves pressure decrease and change. By utilizing multiple hydraulic transformers 210 with different area ratios, the initial oil pressure can be converted into pressure values ​​of different magnitudes, thereby enabling precise application of stress gradients in the loading module via jacks 304.

[0030] The working steps of this invention are as follows: Power and hydraulic oil supply: After the matching motor 101 starts, it rotates and outputs mechanical energy, which drives the swashplate or eccentric wheel of the plunger pump 100 to rotate, so that the plunger reciprocates in the cylinder. Hydraulic oil is drawn from the oil tank 105 through the oil suction pipe to complete the oil suction process. At the same time, the hydraulic oil is pressurized to form high-pressure oil and enters the first high-pressure pipe 103. High-pressure oil path control: The first high-pressure pipe 103 is divided into a first high-pressure pipe 103 and a second high-pressure pipe 1031. The direction of hydraulic oil flow is controlled by a solenoid directional valve 104 installed on the first high-pressure pipe 103. When the solenoid directional valve 104 controls port A to supply pressure oil and port B to return oil, high-pressure oil enters the first high-pressure pipe 103; when it controls port B to supply pressure oil and port A to return oil, high-pressure oil enters the second high-pressure pipe 1031. High-pressure oil distribution and transformer preparation: The first high-pressure pipe 103 is connected to the first five-way connector 220. The high-pressure oil is distributed to the bottom of the four transformers 210 through the first five-way connector 220 to provide initial high-pressure oil for the transformer process; the second high-pressure pipe 1031 is connected to one end of the second five-way connector 2201, and the other end is connected to the oil return pipe of the jack 304 to provide power for the retraction of the jack 304; Pressure conversion process: Transformer 210 connects to the two sealed force transmission rods 214 through sealed cylinder sleeves with different cross-sectional areas at both ends. The initial pressure hydraulic oil chamber 211 and the transformed hydraulic oil chamber 213 are slidably connected to the two ends of the sealed force transmission rod 214 and sealed through the threaded connecting ring 212. The high-pressure oil entering the initial pressure hydraulic oil chamber 211 is converted according to the ratio of the sealed cylinder sleeve area of ​​the initial pressure hydraulic oil chamber 211 to that of the transformed hydraulic oil chamber 213. When the area ratio is greater than 1, pressure is increased; when it is less than 1, pressure is reduced. The inlet and outlet holes of the threaded connecting ring 212 pass through one side of the initial pressure hydraulic oil chamber 211 to discharge air in the chamber and ensure stable pressure transmission. Gradient pressure transmission: Four transformers 210 convert four different pressure hydraulic oils and deliver them to the corresponding four jacks 304 through the oil inlet pipe of the top jack 304. Loading Implementation: After receiving hydraulic oil of different pressures, the jack 304 generates corresponding pressure, which is applied to the rock sample placed on the top pad 305 of the lower crossbeam 302 through the loading plate 306 assembled at the bottom, forming a stress gradient loading. The upper crossbeam 301, the column 303 and the lower crossbeam 302 form a stable frame, and the base on the bottom surface of the lower crossbeam 302 ensures the overall stability of the equipment. Unloading and Reset: After the loading test is completed, the solenoid directional valve 104 switches the oil circuit direction, so that the high-pressure oil enters the return oil pipe of the jack 304 through the second high-pressure pipe 1031 and the second five-way connector 2201, pushing the jack 304 to retract and complete the unloading.

[0031] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A single hydraulic pump high-synchronous stress gradient loading press, comprising a piston pump (100) and a matching motor (101) fixedly connected thereto, characterized in that: A single power source is provided by a plunger pump (100) and a matching motor (101); The transformer mechanism (200) includes four transformers (210) with different multiples. The transformer (210) includes: a sealing force transmission rod (214) with different cross-sectional area sealing cylinder sleeves connected to both ends respectively, an initial pressure hydraulic oil chamber (211) and a transformed hydraulic oil chamber (213) slidably connected to both ends of the sealing force transmission rods (214). By designing different area ratios of the sealing cylinder liners, the initial hydraulic pressure can be controlled: when the ratio of the area of ​​the sealing cylinder liner in the initial pressure hydraulic oil chamber (211) to the area of ​​the sealing cylinder liner in the pressure-changed hydraulic oil chamber (213) is greater than 1, the system achieves pressure increase and pressure change; when the ratio is less than 1, the system achieves pressure decrease and pressure change. Each transformer (210) has a jack oil inlet pipe (400) connected to its top, and a first five-way connector (220) is installed below each of the four transformers (210). The top of the first five-way connector (220) is connected to the bottom of the four transformers (210). The transformer mechanism (200) is provided with a loading mechanism (300) on one side, which includes: four jacks (304) that are connected to the output end of the four jack oil inlet pipes (400), an upper crossbeam (301) fixedly installed on the top of the four jacks (304), a column (303) fixedly connected to the bottom of the upper crossbeam (301), and a lower crossbeam (302) installed at the bottom of the column (303). The bottom of the four jacks (304) is equipped with loading plates (306), and the top of the lower crossbeam (302) is fixedly installed with pads (305). An oil tank (105) is fixedly installed at the bottom of the matching motor (101). An overflow return oil pipeline (102) and an oil suction pipeline are connected through the top of the oil tank (105), and the top of the oil suction pipeline is connected to the plunger pump (100). An overflow valve is fixedly installed on the overflow return oil line (102), and the overflow return oil line (102) is connected to the first high pressure line (103). The oil tank (105) is also connected to the second high pressure line (1031). The first high pressure line (103) and the second high pressure line (1031) are both equipped with a solenoid directional valve (104) to control the flow direction of the hydraulic oil. The first high-pressure pipe (103) is connected to the first five-way connector (220), and one end of the second high-pressure pipe (1031) is connected to the second five-way connector (2201), and the other interfaces of the second five-way connector (2201) are connected to the jack return oil pipe (401). The outer wall of the initial pressure hydraulic oil chamber (211) is threadedly connected to a threaded connecting ring (212), and one end of the threaded connecting ring (212) is threadedly connected to the outer wall of the pressure-transformed hydraulic oil chamber (213).

2. The single hydraulic pump strong synchronous stress gradient loading press according to claim 1, characterized in that: The initial pressure hydraulic oil chamber (211) and the pressure-transformed hydraulic oil chamber (213) are used to store hydraulic oil. One side of the initial pressure hydraulic oil chamber (211) is connected to an air inlet and outlet hole, and the air inlet and outlet hole passes through a threaded connecting ring (212).

3. The single hydraulic pump strong synchronous stress gradient loading press according to claim 1, characterized in that: The bottom surface of the lower crossbeam (302) is fixedly connected to a base, and the output end of the jack (304) is connected to the jack return oil pipe (401).

Images