Electro-hydraulic servo sample hydraulic forming and demolding device and sample preparation method thereof

Abstract

The application discloses an electro-hydraulic servo sample hydraulic forming and demolding device and a sample preparation method thereof. The device comprises a self-balancing pressurizing frame, a vertical driving part and a horizontal driving part. A lower pressurizing assembly and an upper pressurizing assembly are oppositely arranged and correspondingly centered on the self-balancing pressurizing frame, and a mold cavity assembly is arranged between the lower pressurizing assembly and the upper pressurizing assembly. The vertical driving part is connected with the lower pressurizing assembly and drives the lower pressurizing assembly to vertically move towards the upper pressurizing assembly, so as to extrude a sample raw material in the mold cavity assembly. The horizontal driving part is connected with the upper pressurizing assembly and drives the upper pressurizing assembly to horizontally move, so that the upper pressurizing assembly translates from directly above the mold cavity assembly to one side outside the self-balancing pressurizing frame, and a sample extruded and formed in the mold cavity assembly is demolded.

Description

Technical Field

[0001] This application relates to the field of geotechnical test sample preparation technology, and in particular to an electro-hydraulic servo sample hydraulic forming and demolding device and its sample preparation method. Background Technology

[0002] Test specimen compression is an indispensable step in the preparation of various geotechnical test samples. Traditional sample preparation equipment involves loading the powdered or granular filler to be compressed into a mold cavity with a movable base, then using a pressure frame and a manual jack to press the top block into the mold cavity to achieve sample compression. Traditional compression methods are complex, involve cumbersome demolding, have low molding efficiency, and cannot guarantee sample uniformity, affecting test results. Furthermore, the molds used in traditional compression methods produce specimens of fixed heights, which cannot meet the specific requirements of multiple specimen heights within a single mold. Summary of the Invention

[0003] This application provides an electro-hydraulic servo specimen hydraulic forming and demolding device and its sample preparation method, which can realize unidirectional and bidirectional automatic pressing and demolding of specimens, and is suitable for pressing specimens of various specifications in geotechnical testing. The technical solution is as follows:

[0004] This application provides an electro-hydraulic servo sample hydraulic forming and demolding device, including a self-balancing pressure frame, a vertical drive unit, and a horizontal drive unit. A lower pressure assembly and an upper pressure assembly are disposed opposite to each other and centered on the self-balancing pressure frame. A mold cavity assembly is provided between the lower pressure assembly and the upper pressure assembly. The vertical drive unit is connected to the lower pressure assembly and drives the lower pressure assembly to move vertically toward the upper pressure assembly to compress the sample raw material inside the mold cavity assembly. The horizontal drive unit is connected to the upper pressure assembly and drives the upper pressure assembly to move laterally, so that the upper pressure assembly is translated from directly above the lower pressure assembly to one side outside the self-balancing pressure frame to demold the sample formed by compression inside the mold cavity assembly.

[0005] For example, in an embodiment of the electro-hydraulic servo sample hydraulic forming and demolding device, the self-balancing pressure frame includes an upper reaction plate and a lower reaction plate arranged opposite to each other. Several guide optical shafts are provided between the upper reaction plate and the lower reaction plate so that the upper reaction plate, the lower reaction plate and the guide optical shafts form a self-balancing system. The mold cavity assembly and the lower pressure assembly pass through the guide optical shafts and can move vertically up and down along the guide optical shafts. The upper pressure assembly is located on the side of the upper reaction plate facing the lower reaction plate and the upper reaction plate restricts the vertical movement of the upper pressure assembly.

[0006] For example, in an embodiment of an electro-hydraulic servo sample hydraulic forming and demolding device, the mold cavity assembly includes an upper mold cavity pressure plate and a lower mold cavity pressure plate sleeved on the guide optical shaft and arranged opposite to each other. Several tie rods are provided between the upper mold cavity pressure plate and the lower mold cavity pressure plate to tighten them. The upper mold cavity pressure plate and the lower mold cavity pressure plate are provided with centrally corresponding positioning holes. A mold cavity is provided between the upper mold cavity pressure plate and the lower mold cavity pressure plate, and the upper and lower ends of the mold cavity are respectively embedded in the positioning holes. The upper pressure plate of the mold cavity is provided with several follower rods parallel to the guide optical axis on its surface opposite to the lower pressure plate of the mold cavity. The free end of the follower rod extends out of the upper reaction plate, and a mold spring and a spring constraint bolt are sleeved on the free end of the follower rod extending out of the upper reaction plate. The mold cavity assembly is pulled vertically upward along the guide optical axis by the restoring force of the mold spring. A demolding limiting ring is provided on the guide optical axis to limit the upward movement of the mold cavity assembly along the guide optical axis, so as to achieve demolding by relative movement with the lower pressure assembly.

[0007] For example, in an embodiment of an electro-hydraulic servo sample hydraulic forming and demolding device, the lower pressure assembly includes a lower pressure transmission plate, a lower pressure transmission rod, a lower pressure head, and a reset pull rod. The lower pressure transmission plate is sleeved on the guide optical axis. The lower pressure transmission rod is fixed to the surface of the lower pressure transmission plate facing the mold cavity assembly and corresponds to the center of the mold cavity assembly. The lower pressure head is located at the end of the lower pressure transmission rod away from the lower pressure transmission plate and can extend into the mold cavity to squeeze the sample raw material in the mold cavity. The reset pull rod is located on the surface of the lower pressure transmission plate facing the mold cavity assembly and passes through the upper pressure plate and the lower pressure plate of the mold cavity, so that when the lower pressure assembly moves downward to reset, it can drive the mold cavity assembly to move downward to reset.

[0008] For example, in one embodiment of the electro-hydraulic servo sample hydraulic forming and demolding device, the vertical drive unit includes a bidirectional hydraulic cylinder located on the side of the lower pressure transmission plate away from the mold cavity assembly, to drive the lower pressure assembly to move vertically up and down along the guide optical axis; wherein, a tension-compression spoke force sensor is provided between the bidirectional hydraulic cylinder and the lower pressure transmission plate to monitor the tension and pressure during the sample preparation process in real time; a wire displacement sensor is provided on the lower reaction plate, and the wire end of the wire displacement sensor is fixed to the lower pressure transmission plate to monitor the upward stroke of the lower pressure head in real time and indirectly control the forming height of the sample.

[0009] For example, in an embodiment of an electro-hydraulic servo sample hydraulic forming and demolding device, the upper pressure assembly includes an upper pressure transmission rod and an upper pressure head. The upper pressure transmission rod is suspended below the transverse drive unit and corresponds to the center of the mold cavity assembly. The upper pressure head is located at the end of the upper pressure transmission rod facing the mold cavity assembly and can extend into the mold cavity to squeeze the sample raw material inside the mold cavity. The transverse drive unit drives the upper pressure transmission rod to move laterally and moves the upper pressure head horizontally to the outside of the self-balancing pressure frame.

[0010] For example, in an embodiment of an electro-hydraulic servo sample hydraulic forming and demolding device, the lateral drive unit includes a lateral moving guide rod, a lateral moving slider, a lateral moving vertical guide bearing, and a cylinder. The lateral moving guide rod is located on the side of the upper reaction plate facing the lower reaction plate. The lateral moving slider passes through the lateral moving guide rod and can move along the lateral moving guide rod. The lateral moving vertical guide bearing is rigidly connected to the lateral moving slider and can move laterally with the lateral moving slider. One end of the upper pressure transmission rod away from the upper pressure head passes through the lateral moving vertical guide bearing and can move laterally with the lateral moving vertical guide bearing. The cylinder includes a lateral moving cylinder spindle and a lateral moving cylinder body. The lateral moving cylinder spindle is rigidly connected to the lateral moving slider to drive the lateral moving slider to move along the lateral moving guide rod.

[0011] For example, in one embodiment of the electro-hydraulic servo sample hydraulic forming and demolding device, a hydraulic pump station and an integrated electrical control cabinet are also included. The integrated hydraulic pump station and electrical control cabinet include electrical control components and a servo hydraulic pump station, and the servo hydraulic pump station provides a hydraulic power source for the vertical drive unit.

[0012] For example, in one embodiment of the electro-hydraulic servo sample hydraulic forming and demolding device, a mobile compressed air source is also included. The mobile compressed air source includes an air compressor pump, a compressed air tank and an air pipe. The air pipe is connected to the hydraulic pump station and the electrical control integrated cabinet to provide a pneumatic power source for the transverse drive unit.

[0013] The second aspect of this application provides a sample preparation method for the aforementioned electro-hydraulic servo sample hydraulic forming and demolding device, comprising the following steps: S1 Installing the mold; selecting a sample preparation mold size that meets the test requirements, including an upper pressure head, a lower pressure head, and a mold cavity; screwing the upper pressure head and the lower pressure head into the external threads at the ends of the corresponding upper pressure transmission rod and lower pressure transmission rod, respectively; placing the mold cavity between the upper pressure plate and the lower pressure plate of the mold cavity, ensuring that the positioning through hole between the upper pressure plate and the lower pressure plate of the mold cavity is tightly fitted with the mold cavity, and tightening the tie rod between the upper pressure plate and the lower pressure plate of the mold cavity; S2 Setting parameters; setting the hydraulic pump station and electrical control integrated cabinet relative to the wire displacement sensor. The corresponding upper and lower limit alarm parameters of the digital display instrument of the wire displacement gauge are used to limit the sample preparation height and the upward stroke of the lower pressure head; S3 Adjust the pressure and speed of the bidirectional hydraulic cylinder; Press the oil pump start switch to start the hydraulic pump station, and adjust the upper limit pressure and lifting speed of the bidirectional hydraulic cylinder to a suitable range through the manual control switch for cylinder lifting, speed regulating throttle valve, and pressure regulating overflow valve; S4 Initialization and reset; Press the reset switch to start the sample preparation initialization and reset process. The bidirectional hydraulic cylinder drives the lower pressure assembly to move downward. When the lower pressure assembly moves downward to the top of the reset pull rod and contacts the upper surface of the mold cavity pressure plate, the reset pull rod simultaneously pulls down the mold cavity assembly, and the mold spring is compressed synchronously until the hydraulic pressure is reduced to the specified value. When the hydraulic cylinder reaches its lower stroke limit, the cylinder of the transverse drive unit starts, pulling the upper pressure assembly out of the self-balancing pressure frame; S5 Filling; Layered filling of sample raw materials into the mold cavity; S6 Automated sample preparation; Press the sample preparation switch to start the fully automatic sample pressing and demolding process; First, the cylinder of the transverse drive unit starts, pushing the upper pressure assembly into the self-balancing pressure frame, so that the upper pressure head is directly above the mold cavity and centered; Then, the bidirectional hydraulic cylinder of the vertical drive unit begins to rise, and the lower pressure assembly rises synchronously. The mold cavity assembly, initially held by the reset rod, rises under the action of the mold spring restoring force; Next, when the upper pressure head enters the mold cavity... When the packing material is pressed inside the cavity, the packing material enters the pressing stage. In the initial stage of the pressing stage, when the frictional force between the pressurized packing material and the inner wall of the mold cavity is less than the weight of the mold cavity assembly, the lower pressing head rises along the inner wall of the mold cavity, and the bottom of the packing material inside the mold cavity is pressed. When the frictional force between the pressurized packing material and the inner wall of the mold cavity is greater than the weight of the mold cavity assembly, the mold cavity assembly rises with the lower pressing head, and the packing material inside the mold cavity begins to be pressed under the constraint of the upper pressing head. The rising stroke of the lower pressing head is monitored in real time by a wire displacement sensor to indirectly obtain the distance between the upper and lower pressing heads, thereby controlling the sample preparation height. When the sample preparation height is reached, the pressing process automatically stops and the demolding process begins. S7 automated demolding.In the initial stage of the demolding process, the bidirectional hydraulic cylinder descends, causing the lower pressure assembly to descend synchronously until the upper pressure head is completely detached from the mold cavity. Then, the cylinder of the transverse drive unit activates, pulling the upper pressure assembly outside the self-balancing pressure frame. Next, the bidirectional hydraulic cylinder rises again, and the lower pressure assembly rises synchronously. The mold cavity assembly, initially held by the reset rod, rises under the restoring force of the mold spring, and rises synchronously with the rise of the bidirectional hydraulic cylinder. After the mold spring has fully returned to its original length, the lower pressure head... The pressing head and the inside of the mold cavity begin to move relative to each other. When the lower pressing head contacts the bottom of the already pressed sample inside the mold cavity, because the weight of the sample and the inner wall of the mold cavity is much greater than the weight of the mold cavity assembly, the mold cavity assembly rises with the lifting of the lower pressing head. When the mold cavity assembly contacts the demolding limit ring, the lower pressing head and the inside of the mold cavity begin to move relative to each other again, pushing the pressed sample upward until the upper limit of the upward stroke of the lower pressing head is reached. At this point, the sample is also pushed out of the mold cavity, thus completing the demolding process.

[0014] The beneficial effects of the electro-hydraulic servo sample hydraulic forming and demolding device and sample preparation method provided in some embodiments of this application are as follows: This application, through innovative designs such as a self-balancing pressure frame, upward follow-up of the mold cavity assembly, lateral air-driven upper pressure component, quick assembly of the mold cavity assembly, digital control of forming height, and digital monitoring of forming pressure, combined with a PLC electrical automation control program, achieves full automation of the sample pressing and demolding process, solving the problems of cumbersome procedures and low efficiency in traditional sample preparation methods. This application integrates sample pressing and demolding, unidirectional and bidirectional pressure, meeting different functional requirements. Compared with traditional sample preparation machines, this application not only improves the efficiency of sample pressing during geotechnical testing, but also achieves precise control of sample height and pressure values ​​during sample preparation through the use of a wire displacement sensor and a tension-compression wheel spoke force sensor. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this specification or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a front view of the overall structure of the electro-hydraulic servo sample hydraulic forming and demolding device of this application;

[0017] Figure 2 This is a three-dimensional view of the overall structure of the electro-hydraulic servo sample hydraulic forming and demolding device of this application;

[0018] Figure 3This is a schematic diagram of the overall structure of the hydraulic pump station and electrical control integrated cabinet of this application. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as “comprising” or “including” mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as “connected” or “linked” are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as “upper,” “lower,” “left,” and “right” are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0021] The first aspect of this application provides an electro-hydraulic servo sample hydraulic forming and demolding device, such as... Figure 1-3 As shown, the device includes a self-balancing pressure frame 11, a vertical drive unit 14, and a horizontal drive unit 16. A lower pressure assembly 13 and an upper pressure assembly 15 are disposed opposite each other and centered on the self-balancing pressure frame 11. A mold cavity assembly 12 is provided between the lower pressure assembly 13 and the upper pressure assembly 15. The vertical drive unit 14 is connected to the lower pressure assembly 13 and drives the lower pressure assembly 13 to move vertically toward the upper pressure assembly 15 to compress the sample raw material inside the mold cavity assembly 12. The horizontal drive unit 16 is connected to the upper pressure assembly 15 and drives the upper pressure assembly 15 to move laterally, so that the upper pressure assembly 15 is moved from directly above the lower pressure assembly 13 to the outside of the self-balancing pressure frame 11 to demold the sample extruded inside the mold cavity assembly 12.

[0022] The electro-hydraulic servo sample hydraulic forming and demolding device of this application can realize the full automation of the sample pressing and demolding process, which solves the problems of cumbersome procedures and low efficiency of traditional sample preparation methods. It can realize unidirectional and bidirectional automatic pressing of samples, and can be applied to the pressing of various specifications of samples in geotechnical tests by quickly changing the mold structure.

[0023] For example, in one embodiment of the electro-hydraulic servo sample hydraulic forming and demolding apparatus, such as Figure 1-2 As shown, the self-balancing pressure frame 11 includes an upper reaction plate 1101 and a lower reaction plate 1102 arranged opposite to each other. Several guide optical shafts 1103 are provided between the upper reaction plate 1101 and the lower reaction plate 1102 to form a self-balancing system. The mold cavity assembly 12 and the lower pressure assembly 13 pass through the guide optical shafts 1103 and can move vertically up and down along the guide optical shafts 1103. The upper pressure assembly 15 is located on the side of the upper reaction plate 1101 facing the lower reaction plate 1102 and the upper reaction plate 1101 restricts the vertical movement of the upper pressure assembly 15.

[0024] Specifically, the upper reaction plate 1101 and lower reaction plate 1102 of the self-balancing main frame 11 are made of 45# steel, and the guide optical shaft 1103 is an externally chrome-plated and hardened 45# steel optical shaft. The self-balancing pressure frame 11 uses ordinary filler, which is easy to process. The assembly details are cleverly designed, which not only meets the structural strength of the sample frame, but also reduces the processing cost. The quick-assembly mold cavity assembly 12 is made of 45# steel with integral hardening and heat treatment and surface finishing, which ensures the rigidity, strength and stability of the whole device and improves the wear resistance of the mold cavity assembly.

[0025] Furthermore, four guide shafts 1103 are provided between the upper reaction plate 1101 and the lower reaction plate 1102, forming a self-balancing pressure frame 11. The guide shafts 1103 have external threads with positioning platforms at both ends. Both the upper and lower reaction plates 1101 and 1102 have internal holes with positioning platforms. The guide shafts 1103 are fastened to the upper and lower reaction plates 1101 and 1102 using high-strength hexagonal nuts 1104, with high-strength spring washers 1105 to prevent loosening. Four heavy-duty casters 1106 with brakes are bolted to the bottom of the self-balancing pressure frame 11, allowing the self-balancing pressure system to move freely.

[0026] Among them, the upper reaction plate 1101, the lower reaction plate 1102 and the guide optical axis 1103 all adopt the shoulder positioning, which ensures the positioning accuracy and provides a reliable guarantee for the precise positioning of the automated sample preparation process.

[0027] For example, in one embodiment of the electro-hydraulic servo sample hydraulic forming and demolding apparatus, such as Figure 1-2As shown, the mold cavity assembly 12 includes an upper mold cavity pressure plate 1201 and a lower mold cavity pressure plate 1202 sleeved on the guide optical shaft 1103 and arranged opposite to each other. Several tie rods 1204 are provided between the upper mold cavity pressure plate 1201 and the lower mold cavity pressure plate 1202 to tighten them. Center-corresponding positioning holes are provided on the upper mold cavity pressure plate 1201 and the lower mold cavity pressure plate 1202. A mold cavity 1205 is provided between the upper mold cavity pressure plate 1201 and the lower mold cavity pressure plate 1202, and the upper and lower ends of the mold cavity 1205 are respectively embedded in the positioning holes. The upper pressure plate 1201 has several follower rods 1211 parallel to the guide optical axis 1103 on its surface opposite to the lower pressure plate 1202 of the mold cavity. The free end of the follower rod 1211 extends out of the upper pressure plate 1201 of the mold cavity and a mold spring 1208 is provided at the free end of the follower rod 1211. The mold cavity assembly 12 is pulled vertically up and down along the guide optical axis 1103 by the mold spring 1208. A demolding limiting ring 1107 is provided on the guide optical axis 1103 to limit the upward movement of the mold cavity assembly 12 along the guide optical axis 1103, so as to achieve demolding by relative movement with the lower pressure assembly 13.

[0028] The upper pressure plate 1201 and the lower pressure plate 1202 of the mold cavity are provided with positioning through holes that correspond to each other and have positioning shoulders in the middle. The upper and lower ends of the mold cavity 1205 are provided with corresponding shoulders to fit tightly with the positioning through holes. Four tie rods 1204 are provided between the upper pressure plate 1201 and the lower pressure plate 1202 of the mold cavity. The upper pressure plate 1201 and the lower pressure plate 1202 of the mold cavity are tightened by the four tie rods 1204, so that the upper pressure plate 1201, the lower pressure plate 1202 and the mold cavity 1205 are integrated.

[0029] Furthermore, the upper pressure plate 1201 and the lower pressure plate 1202 of the mold cavity are mounted on the guide optical shaft 1107 via the first graphite copper sleeve flange self-lubricating bearing 1203, enabling the mold cavity assembly 12 to move vertically along the guide optical shaft 1107. The use of a graphite copper sleeve self-lubricating linear bearing ensures good lubrication and high component reliability, effectively avoiding the drawbacks of ball-type linear bearings that reduce service life due to easy wear.

[0030] Furthermore, four follower rods 1211 are provided on the surface of the upper pressure plate 1201 of the mold cavity opposite to the lower pressure plate 1202 of the mold cavity, and are guided by a first linear guide bearing 1210 fixed on the upper reaction plate 1101. From bottom to top, the portion of the follower rods 1211 extending beyond the upper surface of the upper reaction plate 1101 is fitted with an annular flat washer 1209, a buffer nylon washer 1207, a mold spring 1208, and a spring-constrained flat-head bolt 1206.

[0031] According to the above embodiment, by using a precisely selected mold spring 1208, the mold cavity assembly 12 can be lifted dynamically during the hydraulic pressing process of the vertical drive unit 14, thus cleverly realizing bidirectional pressurization of the packing under the action of a single hydraulic cylinder.

[0032] For example, in one embodiment of the electro-hydraulic servo sample hydraulic forming and demolding apparatus, such as Figure 1-2 As shown, the lower pressure assembly 13 includes a lower pressure transmission plate 1301, a lower pressure transmission rod 1304, a lower pressure head 1303, and a reset pull rod 1309. The lower pressure transmission plate 1301 is sleeved on the guide optical shaft 1103; the lower pressure transmission rod 1304 is fixed to the surface of the lower pressure transmission plate 1301 facing the mold cavity assembly 12 and corresponds to the center of the mold cavity assembly 12; the lower pressure head 1303 is located on the lower... The end of the pressure transmission rod 1304 is away from the lower pressure transmission plate 1301 and can extend into the mold cavity 1205 to compress the sample raw material in the mold cavity 1205; the reset pull rod 1309 is located on the surface of the lower pressure transmission plate 1301 facing the mold cavity assembly 12 and passes through the upper mold cavity pressure plate 1201 and the lower mold cavity pressure plate 1202, so that when the lower pressure assembly 13 moves downward to reset, it can drive the mold cavity assembly 12 to move downward to reset.

[0033] The lower pressure transmission plate 1301 is mounted on the guide shaft 1107 via four second graphite copper sleeve flange self-lubricating bearings 1302. The use of graphite copper sleeve self-lubricating linear bearings ensures good lubrication and high component reliability, effectively avoiding the drawbacks of ball-type linear bearings that reduce service life due to easy wear.

[0034] Furthermore, a lower pressure transmission rod fixing flange plate 1305 is provided in the middle of the lower pressure transmission plate 1301. The lower pressure transmission rod 1304 has external threads processed at both ends. One end is used to assemble the lower pressure head 1303, and the other end is fixed on the lower pressure transmission rod fixing flange plate 1305. The lower pressure transmission rod fixing flange plate 1305 is connected to the lower pressure transmission plate 1301 by bolts.

[0035] In order to enable the lower pressure assembly 13 to move the mold cavity assembly 12 downward when it moves downward to reset, a reset pull rod 1309 is designed. By installing a constraint bolt 1306 on the upper end of the reset pull rod 1309, when the lower pressure assembly 13 moves down to the upper surface of the lower pressure plate 1202 of the mold cavity when the lower end face of the constraint bolt 1306 on the upper end of the reset pull rod 1309 contacts the upper surface of the mold cavity lower pressure plate 1202, the reset pull rod 1309 pulls down the mold cavity assembly 12 simultaneously, and the mold spring 1208 is compressed simultaneously until the bidirectional hydraulic cylinder 14 reaches the lower limit of its stroke.

[0036] Furthermore, the reset tie rod 1309 and the mold cavity assembly 12 are not rigidly connected, but instead pass directly through the first linear guide bearing 1307 on the upper mold cavity pressure plate 1201 and the second linear guide bearing 1308 on the lower mold cavity pressure plate. The use of graphite copper bushing self-lubricating linear bearings ensures good lubrication and high component reliability, effectively avoiding the drawbacks of ball-type linear bearings that lead to reduced service life due to easy wear.

[0037] The lower pressure transmission rod 1304 and the lower pressure head 1303 are positioned using a shoulder positioning system, which ensures positioning accuracy and provides a reliable guarantee for precise positioning in the automated sample preparation process.

[0038] For example, in one embodiment of the electro-hydraulic servo sample hydraulic forming and demolding apparatus, such as Figure 1-2 As shown, the vertical drive unit 14 includes a bidirectional hydraulic cylinder 1402 located on the side of the lower pressure transmission plate 1301 away from the mold cavity assembly 12, to drive the lower pressure assembly 13 to move vertically up and down along the guide optical axis 1103. A tension-compression spoke force sensor 1401 is provided between the bidirectional hydraulic cylinder 1402 and the lower pressure transmission plate 1301 to monitor the tension and pressure during the sample preparation process in real time. A wire displacement sensor 1403 is provided on the lower reaction plate 1102, and the wire end of the wire displacement sensor 1403 is fixed on the lower pressure transmission plate 1301 to monitor the upward stroke of the lower pressure head 1303 in real time and indirectly control the molding height of the sample.

[0039] The tension-compression spoke force sensor 1401 is connected to the lower pressure transmission plate 1305 by bolts and is used to monitor the tension and pressure during the sample preparation process in real time. The reset oil inlet pipe 1404 and the rise oil inlet pipe 1405 are connected to the bidirectional hydraulic cylinder 1402 to provide hydraulic power to the bidirectional hydraulic cylinder 1402. The connection between the reset oil inlet pipe 1404 and the rise oil inlet pipe 1405 and the bidirectional hydraulic cylinder 1402 adopts a quick plug-in method.

[0040] For example, in one embodiment of the electro-hydraulic servo sample hydraulic forming and demolding apparatus, such as Figure 1-2As shown, the upper pressure assembly 15 includes an upper pressure transmission rod 1501 and an upper pressure head 1502: the upper pressure transmission rod 1501 is suspended below the transverse drive unit and corresponds to the center of the mold cavity assembly 12; the upper pressure head 1502 is located at the end of the upper pressure transmission rod 1501 facing the mold cavity assembly 12, and can extend into the mold cavity 1205 to compress the sample in the mold cavity 1205; wherein, the transverse drive unit 16 drives the upper pressure transmission rod 1501 to move laterally and moves the upper pressure head 1502 horizontally to the outside of the self-balancing pressure frame 11.

[0041] For example, in one embodiment of the electro-hydraulic servo sample hydraulic forming and demolding apparatus, such as Figure 1-2 As shown, the lateral drive unit 16 includes a lateral moving guide rod 1601, a lateral moving slider 1602, a lateral moving vertical guide bearing 1603, and a cylinder. The lateral moving guide rod 1601 is located on the side of the upper reaction plate 1101 facing the lower reaction plate 1102. The lateral moving slider 1602 passes through the lateral moving guide rod 1601 and can move along the lateral moving guide rod 1601. The lateral moving vertical guide bearing 1603 is rigidly connected to the lateral moving slider 1602 and can move laterally with it. One end of the upper pressure transmission rod 1501 away from the upper pressure head 1502 passes through the lateral moving vertical guide bearing 1603 and can move laterally with it. The cylinder includes a lateral moving cylinder spindle 1604 and a lateral moving cylinder body 1605. The lateral moving cylinder spindle 1604 is rigidly connected to the lateral moving slider 1602 to drive it to move along the lateral moving guide rod 1601.

[0042] The upper pressure head 1502 is a workpiece with an internally threaded hole, which is connected to the upper pressure transmission rod 1501 with an externally threaded end. The upper pressure transmission rod 1501 and the upper pressure head 1502 are positioned using a shoulder positioning method, which ensures positioning accuracy and provides a reliable guarantee for precise positioning in the automated sample preparation process. The upper pressure assembly 15 is suspended below the transverse drive unit 16 through the transverse movement vertical guide bearing 1603.

[0043] The 1603 lateral movement vertical guide bearing adopts a graphite copper sleeve self-lubricating linear bearing, which has good lubrication and high component reliability, effectively avoiding the defects of ball linear bearings that are easily damaged and thus reduce service life.

[0044] The upper pressure transmission rod 1501 in the upper pressure head assembly 15 has a gap of about 2mm between its top end face and the upper reaction plate 1101. This is to prevent the upper pressure head assembly 15 from being unable to move laterally normally during demolding because the top end face of the upper pressure transmission rod 1501 would contact the lower surface of the upper reaction plate 1101 and generate friction.

[0045] The end of the transverse moving cylinder spindle 1604 is machined with an external thread, which is rigidly connected to the internal thread hole on the transverse moving slider 1602.

[0046] The intake pipe 1606 and the exhaust pipe 1607 are connected to the cylinder body 1605 of the transverse moving cylinder to provide a pneumatic power source for the cylinder, and the intake pipe 1606 and the exhaust pipe 1607 are connected to the cylinder body 1605 of the transverse moving cylinder by a quick-connect method.

[0047] For example, in one embodiment of the electro-hydraulic servo sample hydraulic forming and demolding apparatus, such as Figure 1-3 As shown, it also includes a hydraulic pump station and an integrated electrical control cabinet 2. The integrated hydraulic pump station and electrical control cabinet 2 includes an electrical control component 21 and a servo hydraulic pump station 22, and the servo hydraulic pump station 22 provides a hydraulic power source for the vertical drive unit 14.

[0048] The electrical control component 21 includes a wire displacement digital display instrument 2101, an oil pressure gauge 2102, a force value digital display instrument 2103, a dustproof cooling fan 2104, an emergency stop switch 2105, a power input line 2106, a power switch 2107, an oil pump start switch 2108, a sample preparation switch 2109, a reset switch 2110, a cylinder lifting manual control switch 2111, a cylinder in / out manual control switch 2112, and an electrical control component module 2113. The wire displacement digital display instrument 2101 displays the value of the wire displacement sensor 1403 in real time, the oil pressure gauge 2102 monitors the oil pressure of the servo hydraulic pump station 22 in real time, and the force value digital display instrument 2103 displays the force value of the tension / compression type spoke force sensor 1401 in real time. Based on real-time feedback of displacement and force, and through PLC programming, functions such as fully automatic sample preparation, fully automatic demolding, automatic reset, manual lifting of hydraulic cylinders, and manual entry and exit of pneumatic cylinders can be realized through function buttons such as oil pump start switch 2108, sample preparation switch 2109, reset switch 2110, manual control switch for lifting hydraulic cylinders 2111, and manual control switch for entering and exiting pneumatic cylinders 2112.

[0049] The servo hydraulic pump station 22 mainly includes a speed regulating throttle valve 2201, a pressure regulating overflow valve 2202, a hydraulic pump station air-cooled heat dissipation dust cover 2203, a pump station first oil outlet 2204, a pump station second oil outlet 2205, a hydraulic oil tank 2206, a servo valve 2207, a hydraulic pump 2208, a hydraulic hard pipe 2209, and an air-cooled heat dissipation fan 2210; furthermore, the hydraulic pump station and electrical control integrated cabinet 2 also includes a support and sheet metal component assembly 23, which is composed of a control cabinet sheet metal shell 2301, a universal wheel with brake 2302, and a square tube support frame 2303. The servo hydraulic pump station 22 is fixed to the square tube support frame 2303 by bolts; the braked caster wheel 2302 is fixed to the lower part of the square tube support frame 2303 for moving the hydraulic pump station and the electrical control integrated cabinet 2; the square tube support frame 2303 is embedded inside the sheet metal shell 2301 of the control cabinet and is connected by bolts.

[0050] For example, in one embodiment of the electro-hydraulic servo sample hydraulic forming and demolding apparatus, such as Figure 1-3 As shown, it also includes a mobile compressed air source 3, which includes an air compressor pump 31, a compressed air tank 32 and an air pipe 38. The air pipe 38 is connected to the hydraulic pump station and the electrical control cabinet 2 to provide a pneumatic power source for the transverse drive unit 16.

[0051] Furthermore, the mobile compressed air source 3 also includes casters 33, vibration-damping pads 34, air pressure switch 35, air pressure gauge 36, air outlet valve 37, air inlet 39, first air outlet 310, and second air outlet 311. Compressed air from the air compressor pump 31 and compressed air tank 32 enters the hydraulic pump station and electrical control integrated cabinet 2 through the air pipe 38 from the air inlet 39. The air inlet pipe 1606 and the air outlet pipe 1607 are connected to the first air outlet 310 and the second air outlet 311 by a quick-connect method.

[0052] The second aspect of this application provides a sample preparation method for an electro-hydraulic servo sample hydraulic forming and demolding device, comprising the following steps:

[0053] S1 Install the mold; Select a sample mold size that meets the test requirements, including the upper pressure head 1502, the lower pressure head 1303, and the mold cavity 1205; Screw the upper pressure head 1502 and the lower pressure head 1303 into the external threads at the ends of the corresponding upper pressure transmission rod 1501 and lower pressure transmission rod 1304, respectively; Place the mold cavity 1205 between the upper mold cavity pressure plate 1201 and the lower mold cavity pressure plate 1202, ensuring that the shoulder positioning through hole in the middle of the upper mold cavity pressure plate 1201 and the lower mold cavity pressure plate 1202 is tightly fitted with the shoulders at both ends of the mold cavity 1205; Tighten the tie rod 1204 between the upper mold cavity pressure plate 1201 and the lower mold cavity pressure plate 1202.

[0054] S2 turns on the power and sets the parameters; rotate the power switch 2107 to connect the power supply of the electrical control cabinet, and set the upper and lower limit alarm parameters of the digital display instrument of the wire displacement meter corresponding to the wire displacement sensor 1403 on the hydraulic pump station and the electrical control integrated cabinet 2, so as to limit the sample preparation height and the upward stroke of the lower pressure head 1303.

[0055] S3 starts the hydraulic pump station and adjusts the pressure and speed of the bidirectional hydraulic cylinder 1402; press the oil pump start switch 2108 to start the hydraulic pump station, and adjust the upper limit pressure and lifting speed of the bidirectional hydraulic cylinder 1402 to a suitable range through the cylinder lifting manual control switch 2111, speed regulating throttle valve 2201, and pressure regulating overflow valve 2202.

[0056] S4 Initialization Reset; Press the reset switch 2110 to start the sample initialization reset process. The bidirectional hydraulic cylinder 14 drives the lower pressure assembly 13 to move downward. When the lower pressure assembly 13 moves downward to the point where the lower end face of the constraint bolt 1306 at the top of the reset pull rod 1309 contacts the upper surface of the mold cavity upper pressure plate 1202, the reset pull rod 1309 simultaneously pulls down the mold cavity assembly 12, and the mold spring 1208 is compressed synchronously until the hydraulic cylinder 14 reaches the lower limit of the stroke. Then, the cylinder of the transverse drive part 16 starts to pull the upper pressure assembly 15 out of the self-balancing pressure frame 11.

[0057] S5 filler; fill the mold cavity 1205 with sample raw materials in layers, and if necessary, filter plates or filter paper and other accessories can be placed in.

[0058] S6 Automated Sample Preparation; Press the sample preparation switch 2109 to begin the fully automatic sample pressing and demolding process; First, the cylinder of the horizontal drive unit 16 is activated to push the upper pressure assembly 15 into the self-balancing pressure frame 11, so that the upper pressure head 1502 is directly above and centered on the mold cavity 1205; Then, the bidirectional hydraulic cylinder 1402 of the vertical drive unit 14 begins to rise, and the lower pressure assembly 13 rises synchronously. The mold cavity assembly 12, which is initially held by the reset rod 1309, moves under the restoring force of the mold spring 1208. The packing material rises; then, when the upper pressure head 1502 enters the mold cavity 1205 and presses down on the packing, the packing enters the pressing stage; in the early stage of the pressing stage, when the friction between the pressurized packing and the inner wall of the mold cavity 1205 is less than the weight of the mold cavity assembly 12, the lower pressure head 1303 rises along the inner wall of the mold cavity 1205, and the bottom of the packing inside the mold cavity 1205 is pressurized; air and moisture are discharged from the gap between the lower pressure head 1303 and the inner wall of the mold cavity 1205, the packing gradually becomes denser, and the friction between the pressurized packing and the inner wall of the mold cavity 1205 gradually increases. When the frictional force between the pressurized packing and the inner wall of the mold cavity 1205 is greater than the weight of the mold cavity assembly 12, the lower pressurizing head 1303 and the mold cavity 1205 no longer have relative movement. The mold cavity assembly 12 rises with the lower pressurizing head 1303, and the packing inside the mold cavity 1205 begins to be pressurized under the constraint of the upper pressurizing head 1505. Since the upper pressurizing assembly 15 cannot move freely upward under the constraint of the upper reaction plate 1101, the distance between the bottom surface of the upper pressurizing head 1502 and the top surface of the lower pressurizing head 1303 can be indirectly obtained by monitoring the rising stroke of the lower pressurizing head 1303 in real time through the wire displacement sensor 1403, thereby controlling the sample preparation height. When the sample preparation height is reached, the pressing process is automatically stopped and the demolding process begins.

[0059] S7 Automated Demolding: In the initial stage of the demolding process, the bidirectional hydraulic cylinder 1402 descends, causing the lower pressure assembly 13 to descend synchronously until the upper pressure head 1502 is completely disengaged from the mold cavity 1205. Then, the cylinder of the transverse drive unit 16 is activated, pulling the upper pressure assembly 15 to the outside of the self-balancing pressure frame 11. Next, the bidirectional hydraulic cylinder 1402 rises again, and the lower pressure assembly 13 rises synchronously. The mold cavity assembly 12, which is initially held by the reset rod 1309, rises under the restoring force of the mold spring 1208. Since the mold cavity is at this time... The frictional force between the sample inside the mold cavity 1205 and the inner wall of the mold cavity 1205 is greater than the weight of the mold cavity assembly 12. The mold cavity assembly 12 will continue to rise as the hydraulic cylinder 14 rises until the first graphite copper sleeve flange self-lubricating bearing 1203 of the mold cavity assembly 12 contacts the demolding limit ring 1107. Then, the lower pressure head 1303 and the inside of the mold cavity 1205 will start to move relative to each other again, pushing the pressed sample upward until the upper limit of the upward stroke of the lower pressure head 1303 is reached. At this time, the sample is also pushed out of the mold cavity 1205, thus completing the demolding process.

[0060] The electro-hydraulic servo sample hydraulic forming and demolding device of this application integrates sample pressing and demolding, unidirectional pressurization and bidirectional pressurization, meeting different functional requirements. Compared with traditional sample preparation machines, this application can not only improve the efficiency of sample pressing in geotechnical testing, but also achieve precise control of sample height and pressure value during sample preparation by using a pull wire displacement sensor and a tension-compression wheel spoke force sensor.

[0061] Although the embodiments of this application have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this application. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, this application is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A method of sample preparation for an electro-hydraulic servo sample hydraulic forming and demolding device, characterized by, The method comprises the following steps: S1 installing the mold; selecting a mold sample size that meets the test requirements, including an upper pressure head, a lower pressure head and a mold cavity; screwing the upper pressure head and the lower pressure head into the outer threads of the corresponding upper pressure transmission rod and the lower pressure transmission rod, respectively, placing the mold cavity between the upper mold pressing plate and the lower mold pressing plate, ensuring that the positioning holes in the middle of the upper mold pressing plate and the lower mold pressing plate are tightly matched with the mold cavity, and tightening the pull rod between the upper mold pressing plate and the lower mold pressing plate; S2 setting parameters; setting the upper and lower limit alarm parameters of the pull wire displacement sensor corresponding to the pull wire displacement meter digital display instrument on the hydraulic pump station and the electrical control integrated cabinet, so as to limit the sample height and the upward stroke of the lower pressure head; S3 adjusting the pressure and speed of the double-acting hydraulic cylinder; starting the hydraulic pump station by pressing the oil pump start switch, and adjusting the upper limit pressure and the lifting speed of the double-acting hydraulic cylinder to a suitable range through the oil cylinder lifting manual control switch, the speed regulating throttle valve and the pressure regulating overflow valve; S4 initializing and resetting; starting the sample initialization and resetting process by pressing the reset switch, and the double-acting hydraulic cylinder drives the lower pressure assembly to descend, when the lower pressure assembly descends to the top end of the reset pull rod and contacts the upper surface of the upper mold pressing plate, the reset pull rod synchronously pulls down the mold cavity assembly, the mold spring is synchronously compressed, until the hydraulic cylinder reaches the lower limit of the stroke, and then the cylinder of the transverse driving part starts to pull the upper pressure assembly out of the self-balancing pressure frame; S5 filling; layering and filling the sample raw material into the mold cavity; S6 automatic sample preparation; starting the full-automatic sample pressing and demolding process by pressing the sample preparation switch; first, the cylinder of the transverse driving part starts to push the upper pressure assembly into the self-balancing pressure frame, and the upper pressure head is located directly above the mold cavity and the center is corresponded; then, the double-acting hydraulic cylinder of the vertical driving part starts to rise, the lower pressure assembly synchronously rises, and the mold cavity assembly held by the reset pull rod rises synchronously under the action of the restoring force of the mold spring; next, when the upper pressure head enters the mold cavity and presses the filling material, the filling material enters the pressing stage; in the early stage of the pressing stage, when the friction between the pressed filling material and the inner wall of the mold cavity is less than the weight of the mold cavity assembly, the lower pressure head rises along the inner wall of the mold cavity, and the bottom of the filling material in the mold cavity is pressed; when the friction between the pressed filling material and the inner wall of the mold cavity is greater than the weight of the mold cavity assembly, the mold cavity assembly rises with the lower pressure head, the filling material in the mold cavity is pressed under the constraint of the upper pressure head, and the lifting stroke of the lower pressure head is monitored in real time through the pull wire displacement sensor to indirectly obtain the distance between the upper pressure head and the lower pressure head, so as to control the sample height, when the sample height is reached, the sample pressing is automatically stopped and the demolding process is started. S7 automatic demolding; in the early stage of demolding process, the lower pressurizing assembly is lowered synchronously by the downward movement of the bidirectional hydraulic cylinder until the upper pressurizing head is completely separated from the mold cavity, then the cylinder of the transverse driving part is started to pull the upper pressurizing assembly to the outside of the self-balancing pressurizing frame, after that, the bidirectional hydraulic cylinder is raised again, the lower pressurizing assembly is raised synchronously, the mold cavity assembly held by the reset pull rod in the initial state is raised along with the bidirectional hydraulic cylinder under the action of the restoring force of the mold spring, until the mold spring is completely restored to the original length, then the lower pressurizing head and the inside of the mold cavity start to move relatively; when the lower pressurizing head contacts the bottom of the sample formed in the inside of the mold cavity, the mold cavity assembly rises along with the lifting of the lower pressurizing head due to the fact that the weight of the sample and the inner wall of the mold cavity is much greater than the self-weight of the mold cavity assembly; when the mold cavity assembly contacts the demolding limiting ring, the lower pressurizing head and the inside of the mold cavity start to move relatively again and push the finished sample upwards until the upper stroke limit of the lower pressurizing head is reached, at this time, the sample is also pushed out of the mold cavity, thus completing the demolding process.

Images