A bicycle brake disc forming process

Abstract

The present invention discloses a bicycle brake disc forming process, which belongs to the technical field of brake disc processing, and solves the problem that the height of the thorn structure is relatively large, the structural strength in the height direction is poor, and when the thorn structure is inserted into the friction material, the thorn structure is subjected to a deflection force due to the deviation of the force direction, so that the thorn structure cannot be inserted into the friction material. The process includes the following steps: preparing materials, weighing Nao friction raw materials and mixing them to form Nao friction materials; debugging equipment, adjusting the cross-sectional area of ​​the forming cavity in the middle and lower molds of the hot press to be larger than the area of ​​the reference friction lining, and the length of the forming cavity in the middle and lower molds of the hot press is larger than the length of the reference friction lining; feeding in batches, and feeding the Nao friction material into the forming cavity in the middle and lower molds of the hot press twice. The present invention can generate friction materials attached to the backing steel, and the connection can be completed without the thorn structure on the backing steel piercing the friction material, thereby ensuring the connection strength between the two and improving the shear strength after connection.

Description

Technical Field

[0001] The invention relates to the technical field of brake disc processing, and in particular to a bicycle brake disc forming process. Background Art

[0002] The structure of the brake disc consists of backing steel and friction material. During the production process, the backing steel coated with glue is first combined with the fully mixed friction material. Then, they are placed in a special mold and the appropriate pressure and temperature are applied using a hot press. After a certain period of curing, the backing steel and friction material can be firmly combined.

[0003] It should be noted that such a connection between the friction material and the backing steel must be made by glue as the connecting medium, and the main connection strength between the two is also reflected by the strength brought by the glue. However, the backing steel and the friction material connected by glue (adhesive) are affected by factors such as temperature and pressure, and may fail or break under the influence of various factors. Therefore, there is a process in the prior art of processing a convex thorn structure on the backing steel, and inserting the convex thorn structure into the friction material when connecting the backing steel and the friction material. For example, the composite disc brake bottom plate with application number CN201380072000.6, whose interlayer can be rolled or pressed to achieve complete embedding of the piercing member in the core material. In some cases, the application of heat or pressure may also be necessary.

[0004] When the above-mentioned existing back steel with burr structure is connected to the friction material, pressure and heating are mainly applied so that the burr structure can penetrate into the friction material and be firmly fixed in the friction material to form a hook-shaped structure to prevent it from detaching from the friction material.

[0005] However, in the actual processing process, since the burr structure on the back steel is mainly formed by repeatedly impacting the back steel with a toothed knife, such as the batch textured material sheet with application number CN201380027691.8, its technical points are: feeding a continuously supplied flat material sheet; and as the sheet is fed, repeatedly impacting the sheet with a toothed knife, so that each knife generates a row of raised and generally sharp structures on the sheet to texture the sheet.

[0006] The burr structure obtained by the above-mentioned method is itself thin in texture. If its height after warping is small, it can maintain a certain structural strength and then penetrate into the friction material under the pressure of the hot press. However, if its height is large, the structural strength in the height direction will deteriorate. When trying to penetrate into the friction material, once the force direction deviates, the friction material will exert a deflection force on the burr structure, so that the tip of the burr structure cannot penetrate into the friction material. On the contrary, the burr structure can penetrate into the friction material again after being squeezed and shortened. During processing, although the back steel and the friction material can maintain an effective connection, eliminating the need for glue (adhesive) when connecting the two, and also having a certain connection strength, and even the shear force between the two is acceptable, the brake disc cannot reach the ultimate strength when the back steel and the friction material are connected. Therefore, with respect to the current connection method, there is still considerable room for improvement in its connection strength.

[0007] Therefore, a bicycle brake disc forming process is proposed to solve or alleviate the above problems. Summary of the invention

[0008] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a bicycle brake disc forming process.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] A bicycle brake disc forming process comprises the following steps:

[0011] Prepare materials: weigh Nao friction raw materials and mix them to form Nao friction materials;

[0012] Equipment debugging: adjust the cross-sectional area of ​​the molding cavity in the middle and lower molds of the hot press to be larger than the reference friction lining area, and the length of the molding cavity in the middle and lower molds of the hot press to be larger than the reference friction lining length;

[0013] Feed the Nao friction material in batches, twice into the molding cavity of the middle and lower mold of the hot press, and lay two symmetrical and U-shaped copper-nickel alloy resistance wires between the two Nao friction materials;

[0014] In the initial hot pressing, a backing steel is placed above the molding cavity in the lower mold of the hot press, and then heated and pressed down into the molding cavity by the upper mold of the hot press to compact and mold the Nao friction material. At this time, the distance between the backing steel and the bottom surface of the molding cavity is greater than the thickness of the reference friction lining;

[0015] Secondary hot pressing, the cross-sectional area of ​​the molding cavity in the middle and lower molds of the hot press is adjusted back to the reference friction lining area, the length of the molding cavity in the middle and lower molds of the hot press is adjusted back to the reference friction lining length, and the middle and lower molds of the hot press are energized to the copper-nickel alloy resistance wire in the length direction of the molding cavity, and the copper-nickel alloy resistance wire heats the inside of the Nao friction material;

[0016] Three hot pressing, the upper mold in the hot press is continuously heated and pressed down twice, at this time, the distance between the back steel and the bottom surface of the forming cavity is equal to the thickness of the reference friction lining;

[0017] Demolding, the upper mold in the hot press is reset, and the length of the molding cavity in the lower mold in the hot press is restored to be greater than the reference friction lining length, and then the friction lining and the backing steel that have finished hot pressing are taken out and demolded in the length direction of the molding cavity;

[0018] The copper-nickel alloy resistance wires protruding at both ends of the friction lining in the length direction are cut, and the friction lining and the backing steel are cooled to room temperature to obtain finished friction linings and backing steel.

[0019] Preferably, the batch feeding also includes setting the amount of Nao friction material fed twice to be the same.

[0020] Preferably, when the copper-nickel alloy resistance wire is laid between the two Nao friction materials, both ends of the copper-nickel alloy resistance are arranged to protrude from the edge of the Nao friction material.

[0021] Preferably, the hot press comprises a frame, a workbench fixedly connected to the frame, a lower mold detachably connected to the top surface of the workbench, an upper mold which can be lifted and displaced in the frame, a lower heating wire arranged in the lower mold, and an upper heating wire arranged in the upper mold, the lower heating wire and the upper heating wire can be turned on and off, the top surface of the lower mold is recessed downward to form a molding cavity, and the top surface of the lower mold is recessed downward to form a slide groove which is connected to the end portion of the molding cavity in the length direction and passes through the side wall of the lower mold, a side module is slidably connected in the slide groove, the spacing between the side modules on both sides is adjusted to change the length of the molding cavity, and a shrinking groove for inserting two ends of the copper-nickel alloy resistance wire is provided on the side module located at the inner wall of the molding cavity, a through hole passing through the side module is provided at the end of the shrinking groove, a copper sleeve arranged in contact with the inner wall thereof is fixedly connected in the shrinking groove, a wire passing through the through hole is fixedly connected to the copper sleeve, and the wire is connected to a power supply.

[0022] Preferably, the hot press also includes a casing fixedly connected to the top surface of the frame, a hydraulic cylinder fixedly connected to the top surface of the frame and located in the casing, the top surface of the workbench is fixedly connected to a plurality of guide columns fixedly connected to the inner top surface of the frame, a connecting plate is slidably connected to the plurality of guide columns, the upper mold is fixedly connected to the bottom surface of the connecting plate, and the hydraulic rod of the hydraulic cylinder passes through the top surface of the frame and is fixedly connected to the top surface of the connecting plate.

[0023] Preferably, the hot press also includes two groups of double-headed hydraulic components for controlling the displacement of the side modules, the double-headed hydraulic components are fixedly connected to the side walls of the frame through a mounting frame, and the double-headed hydraulic components have two movable ends, both of which are detachably connected to the end of the side module, and the two movable ends of the double-headed hydraulic components are alternately connected to the end of the side module, and when the two movable ends of the double-headed hydraulic components alternate, the detachable connection state with the end of the side module is released until the previous movable end is completely detachably connected to the end of the side module until the next movable end.

[0024] Preferably, the end of the side module is fixedly connected with a primary connecting seat and a secondary connecting seat, and the double-headed hydraulic assembly includes a bottom plate, a cylinder body 1 and a cylinder body 2 fixedly connected to the bottom plate, a piston 1 and a piston 2 respectively slidably connected in the cylinder body 1 and the cylinder body 2, a primary piston rod fixedly connected to the piston 1 and penetrating the cylinder body 1, a secondary piston rod fixedly connected to the piston 2 and penetrating the cylinder body 2, a hydraulic cylinder fixedly connected to the top surface of the frame and located in the casing, and a hydraulic pump, the primary piston rod and the secondary piston rod are the two active ends of the double-headed hydraulic assembly, and the ends of the primary piston rod and the secondary piston rod can be respectively embedded in the primary connecting seat. In the connecting seat and the secondary connecting seat, the cylinder body 1 is divided into a primary rear space and a primary front space by piston 1, and the cylinder body 2 is divided into a secondary rear space and a secondary front space by piston 2. The primary rear space and the primary front space are respectively connected with a primary oil guide pipe and a secondary oil guide pipe, and the other ends of the primary oil guide pipe and the secondary oil guide pipe are both connected with the hydraulic cylinder, and the hydraulic pump is connected to the primary oil guide pipe or the secondary oil guide pipe, the primary front space is connected with the secondary rear space through the transmission pipe 1, and the primary front space is connected with the secondary front space through the transmission pipe 2, and the transmission pipe 1 and the transmission pipe 2 are respectively connected with the solenoid valve 1 and the solenoid valve 2.

[0025] Preferably, the double-head hydraulic assembly also includes an electronic control circuit, which collects the temperature of a specific position of the first-level piston rod or the second-level piston rod and controls the other piston rod to extend to a detachable connection with the end of the side module after the temperature exceeds a threshold value, and then controls the first-level piston rod or the second-level piston rod to retract.

[0026] Preferably, the electric control circuit comprises

[0027] A temperature sensor 1, which is arranged on the mounting seat and whose detection end is arranged corresponding to a specific position of the primary piston rod, collects the temperature at the specific position on the primary piston rod and feeds back a temperature signal 1;

[0028] A signal amplifying circuit 1, whose input end is coupled to a temperature sensor 1, receives a temperature signal 1, amplifies and processes it;

[0029] The voltage stabilizing circuit 1 has an input terminal coupled to the output terminal of the signal amplifying circuit 1, and receives the amplified temperature signal and performs voltage stabilizing processing and output;

[0030] A voltage comparison circuit 1, whose input terminal is coupled to the output terminal of the voltage stabilization circuit 1, receives the stabilized temperature signal 1 and sends a first comparison signal when the temperature signal 1 is greater than a preset reference temperature signal 1;

[0031] A second temperature sensor is arranged on the mounting seat and its detection end is arranged corresponding to a specific position of the secondary piston rod, and collects the temperature at the specific position on the secondary piston rod and feeds back a second temperature signal;

[0032] The second signal amplifying circuit has an input end coupled to the second temperature sensor, and receives the second temperature signal and then amplifies and processes it;

[0033] The second voltage stabilizing circuit has an input terminal coupled to the output terminal of the second signal amplifying circuit, receives the amplified temperature signal 2 and performs voltage stabilization processing and output;

[0034] A voltage comparison circuit 3, whose input terminal is coupled to the output terminal of the voltage stabilization circuit 2, receives the stabilized temperature signal 2 and sends a third comparison signal when the temperature signal 2 is greater than a preset reference temperature signal 2;

[0035] A controller, whose input terminal is coupled to the output terminals of the first voltage comparison circuit and the third voltage comparison circuit, and which receives and issues a control instruction signal in response to the first comparison signal or the third comparison signal;

[0036] A motor controller, whose input end is coupled to the output end of the controller, and the output end of the motor controller is coupled to the motor in the hydraulic pump;

[0037] A driving circuit, wherein the controlled end of the driving circuit is coupled to the output end of the controller, the controlled end of the driving circuit is electrically connected, and the solenoid valve 1 and the solenoid valve 2 are connected in series to the controlled end of the driving circuit, and the driving circuit controls the solenoid valve 1 and the solenoid valve 2 to be energized when receiving a control command signal.

[0038] Preferably, the electric control circuit further includes

[0039] A hydraulic sensor 1, wherein the hydraulic sensor 1 is fixedly connected to the bottom plate and its probe extends into the first-stage rear space, and collects the hydraulic strength in the first-stage rear space and feeds back a hydraulic signal 1;

[0040] A voltage comparison circuit 2, whose input terminal is coupled to the output terminal of the hydraulic sensor 1, receives the stabilized hydraulic signal 1 and sends a second comparison signal to the controller when the hydraulic signal 1 is greater than a preset reference hydraulic signal 1;

[0041] A second hydraulic sensor, wherein the second hydraulic sensor is fixedly connected to the bottom plate and its probe extends into the secondary rear space, and collects the hydraulic strength in the secondary rear space and feeds back a second hydraulic signal;

[0042] The voltage comparison circuit 4 has an input terminal coupled to the output terminal of the hydraulic sensor 2, receives the stabilized hydraulic signal 2 and sends a fourth comparison signal to the controller when the hydraulic signal 2 is greater than the preset reference hydraulic signal 2.

[0043] The present invention has the following beneficial effects:

[0044] The present invention can form a friction material attached to the backing steel, and the connection can be completed without the burr structure on the backing steel piercing into the friction material, thereby ensuring the connection strength between the two and improving the shear strength after the connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0046] Figure 1 The structure of the hot press in the present invention is shown in FIG. Figure 1 ;

[0047] Figure 2 for Figure 1 The enlarged view of point A in the middle;

[0048] Figure 3 for Figure 1 The enlarged view of point B in the middle;

[0049] Figure 4 The structure of the hot press in the present invention is shown in FIG. Figure 2 ;

[0050] Figure 5 for Figure 4 Enlarged view of point C in the middle;

[0051] Figure 6 for Figure 4 The enlarged view of point D in the middle;

[0052] Figure 7 is a structural block diagram of the electric control circuit in the present invention;

[0053] Figure 8 It is a schematic structural diagram of the friction lining after demoulding of the present invention;

[0054] Fig. 9 It is a schematic structural diagram of the friction lining of the finished product of the present invention.

[0055] 1. Friction lining; 101. Copper-nickel alloy resistance wire; 2. Frame; 201. Workbench; 202. Casing; 203. Guide column; 204. Connecting plate; 301. Lower mold; 3011. Lower heating wire; 3012. Molding cavity; 3013. Slide; 3014. Side module; 30141. Shrinking groove; 30142. Copper sleeve; 30143. Slide; 30144. Secondary connecting seat; 30145. Primary connecting seat; 30146. Wire; 3015. Guide groove; 302. Upper mold; 3021. Upper heating wire; 4. Mounting frame; 401. Bottom plate; 402. Cylinder body 1; 4021. Primary piston rod; 40211. Temperature sensor 1; 40212. Signal amplifying circuit 1; 40213, voltage stabilizing circuit one; 40214, voltage comparison circuit one; 4022, hydraulic sensor one; 40221, voltage comparison circuit two; 403, cylinder body two; 4031, secondary piston rod; 40311, temperature sensor two; 40312, signal amplifying circuit two; 40313, voltage stabilizing circuit two; 40314, voltage comparison circuit three; 4032, hydraulic sensor two; 40321, voltage comparison circuit four; 404, transmission tube one; 4041, solenoid valve one; 405, transmission tube two; 4051, solenoid valve two; 4061, primary oil guide pipe; 4062, secondary oil guide pipe; 501, controller; 502, motor controller; 503, hydraulic pump; 504, drive circuit. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0057] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0059] In the description of the present invention, it should be understood that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the product of the invention is conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0060] Furthermore, the terms “first”, “second”, “third”, etc. are merely used for distinguishing descriptions and are not to be understood as indicating or implying relative importance.

[0061] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0062] A bicycle brake disc forming process comprises the following steps:

[0063] Prepare materials: weigh Nao friction raw materials and mix them to form Nao friction materials;

[0064] Equipment debugging: adjust the cross-sectional area of ​​the molding cavity 3012 in the lower mold 301 of the hot press to be larger than the area of ​​the reference friction lining 1, and the length of the molding cavity 3012 in the lower mold 301 of the hot press to be larger than the length of the reference friction lining 1;

[0065] Feed the Nao friction material in batches, and feed it into the molding cavity 3012 in the lower mold 301 of the hot press twice. The amount of Nao friction material fed twice is set to be the same, and two symmetrical and U-shaped copper-nickel alloy resistance wires 101 are laid between the two Nao friction materials fed. When the copper-nickel alloy resistance wire 101 is laid between the two Nao friction materials fed, the two ends of the copper-nickel alloy resistance protrude from the edge of the Nao friction material.

[0066] In the first hot pressing, a backing steel is placed above the molding cavity 3012 in the lower mold 301 of the hot press, and then heated by the upper mold 302 of the hot press and pressed down into the molding cavity 3012 to compact and mold the Nao friction material. At this time, the distance between the backing steel and the bottom surface of the molding cavity 3012 is greater than the thickness of the reference friction lining 1;

[0067] Secondary hot pressing, the cross-sectional area of ​​the molding cavity 3012 in the lower mold 301 of the hot press is adjusted back to the area of ​​the reference friction lining 1, the length of the molding cavity 3012 in the lower mold 301 of the hot press is adjusted back to the length of the reference friction lining 1, and the lower mold 301 of the hot press energizes the copper-nickel alloy resistance wire 101 in the length direction of the molding cavity 3012, and the copper-nickel alloy resistance wire 101 heats the inside of the Nao friction material;

[0068] Three hot pressings, the upper mold 302 in the hot press is continuously heated and pressed down twice, at which time the distance between the back steel and the bottom surface of the molding cavity 3012 is equal to the thickness of the reference friction lining 1;

[0069] Demolding, the upper mold 302 in the hot press is reset, and the length of the molding cavity 3012 in the lower mold 301 in the hot press is restored to be greater than the length of the reference friction lining 1, and then the friction lining 1 and the back steel after hot pressing are taken out and demolded from the length direction of the molding cavity 3012;

[0070] Produced, such as Figure 8 and 9 As shown, the copper-nickel alloy resistance wires 101 protruding from both ends of the friction lining 1 in the length direction are cut, and the friction lining 1 and the backing steel are cooled to room temperature to obtain finished friction lining 1 and backing steel.

[0071] According to the above method, the spur-back steel brake disc is formed. In the equipment debugging stage, since the cross-sectional area of ​​the molding cavity 3012 is larger than the area of ​​the reference friction pad 1, which is the initial state of the lower mold 301, this method allows the molding cavity 3012 to be filled with sufficient Nao friction material, and before that, the brake disc that has been hot-pressed for the previous time can be demoulded, providing more space to increase the force on the brake disc that has been hot-pressed for the previous time so that it can leave the molding cavity 3012, avoiding the situation where the peripheral wall of the brake disc is tightly fitted with the inner wall of the molding cavity 3012;

[0072] In the step of feeding in batches, since the feeding amount of the Nao friction material is the same twice, the copper-nickel alloy resistance wire 101 can be located in a relatively central position when it is between the two, so that the relative position of the copper-nickel alloy resistance wire 101 in the friction material will not change too much during the subsequent hot pressing. In this way, it is convenient to confirm the position of the end of the copper-nickel alloy resistance wire 101 after the initial hot pressing of the friction material, so that the inside of the friction material can be heated by the copper-nickel alloy resistance wire 101. When the copper-nickel alloy resistance wire 101 is energized, a heat source appears inside the friction material, and then heat is transferred to the friction material above and below the copper-nickel alloy resistance wire 101, so as to avoid the situation that the upper mold 302 and the lower mold 301 overheat the top and bottom surfaces of the friction material while the inside of the friction material is heated very little, so that the internal structure of the friction material can also be fully heated, and when it is pressed, the various friction raw materials in the friction material can be tightly held together, thereby improving the compactness of the final friction lining 1;

[0073] In the initial hot pressing step, the upper mold 302 plays the role of preliminary molding of the friction material, so that the friction material can form a certain connection relationship with the burr structure on the back steel, so that the friction material can present the prototype of the friction lining 1, and the distance between the back steel and the inner bottom surface of the molding cavity 3012 is greater than the thickness of the reference friction lining 1, which provides a certain reserved space for pressing the friction material in the horizontal direction during the subsequent secondary hot pressing, ensuring that the friction material can be clamped / held tightly by the burr structure on the back steel in the expansion direction of the back steel;

[0074] The secondary hot pressing step is to correct the cross-sectional area and cross-sectional shape of the friction material under the premise of the primary hot pressing, and squeeze the friction material so that it can clamp / hold the burr structure on the back steel in the expansion direction of the back steel, so that the burr structure on the back steel can form a barb-like result in the friction material, so that the friction pad 1 is difficult to separate from the back steel;

[0075] It can be foreseen that the three hot pressings are to press the friction material to the required thickness of the friction lining 1, make a final adjustment to the shape of the friction material, and press the friction material more compactly in the thickness direction, so that the final friction lining 1 has better wear resistance.

[0076] Preferably, if Figure 1 , Figure 3 , Figure 4 , Figure 5 and Figure 6As shown, the hot press comprises a frame 2, a workbench 201 fixedly connected to the frame 2, a lower mold 301 detachably connected to the top surface of the workbench 201, an upper mold 302 which can be lifted and displaced in the frame 2, a lower heating wire 3011 arranged in the lower mold 301, and an upper heating wire 3021 arranged in the upper mold 302, the lower heating wire 3011 and the upper heating wire 3021 can be turned on and off, the top surface of the lower mold 301 is recessed downward to form a molding cavity 3012, and the top surface of the lower mold 301 is recessed downward to form a slide groove 3013 which is connected to the end of the molding cavity 3012 in the length direction and passes through the side wall of the lower mold 301, and a guide groove 3015 is provided on the inner wall of the slide groove 3013. 013 is slidably connected with a side module 3014, and both side edges of the side module 3014 are fixedly connected with sliding bars 30143 slidably connected in the guide groove 3015, the spacing between the side modules 3014 on both sides is adjusted to change the length of the molding cavity 3012, and the side module 3014 located at the inner wall of the molding cavity 3012 is provided with a shrinking groove 30141 for inserting two ends of the copper-nickel alloy resistance wire 101, and a through hole penetrating the side module 3014 is provided at the end of the shrinking groove 30141, and a copper sleeve 30142 arranged to fit the inner wall thereof is fixedly connected in the shrinking groove 30141, and a wire 30146 penetrating the through hole is fixedly connected to the copper sleeve 30142, and the wire 30146 is connected to the power supply.

[0077] When the hot press is actually used for hot pressing, the length of the molding cavity 3012 is adjusted by sliding the side module 3014 in the slide groove 3013 to change the spacing between the side modules 3014 on both sides. When the upper mold 302 and the lower mold 301 need to be hot pressed, it is only necessary to energize the upper heating wire 3021 and the lower heating wire 3011 for a period of time so that both of them can have a certain amount of heat to achieve the hot pressing action. When the side module 3014 needs to heat and pressurize the friction material, it is after the upper mold 302 performs the initial hot pressing on the friction material. At this time, the two ends of the copper-nickel alloy resistance wire 101 are aligned with the shrinkage groove 30141 of the side module 3014. Although the two ends of the copper-nickel alloy resistance wire 101 cannot be aligned with the shrinkage groove 30141, the side module 3014 is not suitable for hot pressing. The slot 30141 is coaxially arranged, but as long as the two ends of the copper-nickel alloy resistance wire 101 are within the projection area coverage of the slot 30141, when the side module 3014 moves toward the side wall of the friction material, the end of the copper-nickel alloy resistance wire 101 can enter the slot 30141, and under the guidance of the inner wall of the slot 30141, the copper sleeve 30142 on the inner wall of the slot 30141 is adhered to and relatively displaced toward its end. At this time, the copper-nickel alloy resistance wire 101 is coupled to the wire 30146 through the copper sleeve 30142. It only needs to connect the wire 30146 to the power supply to ensure that the circuit is unobstructed, so that the copper-nickel alloy resistance wire 101 can be energized to generate heat. In this way, the copper-nickel alloy resistance wire 101 can be heated inside the friction material.

[0078] Preferably, if Figure 1 and Figure 4 As shown, the hot press also includes a casing 202 fixedly connected to the top surface of the frame 2, a hydraulic cylinder fixedly connected to the top surface of the frame 2 and located in the casing 202, a plurality of guide columns 203 fixedly connected to the top surface of the frame 2 are fixedly connected to the top surface of the workbench 201, a connecting plate 204 is slidably connected to the plurality of guide columns 203, an upper mold 302 is fixedly connected to the bottom surface of the connecting plate 204, and a hydraulic rod of the hydraulic cylinder passes through the top surface of the frame 2 and is fixedly connected to the top surface of the connecting plate 204.

[0079] When the hot press machine needs to perform the initial hot pressing or the third hot pressing, the main driving function is performed by the hydraulic cylinder. The hydraulic rod of the hydraulic cylinder will move back and forth in the height direction, thereby driving the connecting plate 204 to move back and forth. The movement of the connecting plate 204 can directly drive the upper mold 302 to move together. In this process, the setting of several guide columns 203 is to ensure that the connecting plate 204 can always maintain a horizontal and stable state when following the hydraulic rod of the hydraulic cylinder to move, and is not prone to tilting or shaking.

[0080] Preferably, the hot press also includes two groups of double-headed hydraulic components for controlling the displacement of the side module 3014, the double-headed hydraulic components are fixedly connected to the side wall of the frame 2 through the mounting frame 4, and the double-headed hydraulic components have two movable ends, both of which are detachably connected to the end of the side module 3014, and the two movable ends of the double-headed hydraulic components are alternately connected to the end of the side module 3014, and when the two movable ends of the double-headed hydraulic components alternate, the detachable connection state with the end of the side module 3014 is released until the previous movable end is completely detachably connected to the end of the side module 3014.

[0081] The double-headed hydraulic assembly is mainly provided to cooperate with the side module 3014 to perform secondary hot pressing on the friction material in the length direction of the molding cavity 3012. One of the movable ends of the double-headed hydraulic assembly is detachably connected to the end of the side module 3014, and when the heat during the hot pressing process of the friction material is transferred from the side module 3014 to the movable end of the double-headed hydraulic assembly, the other movable end of the double-headed hydraulic assembly can be detachably connected to the end of the side module 3014, and then the detachable connection between the previous movable end of the double-headed hydraulic assembly and the end of the side module 3014 is released, so that the movable end after the detachable connection is released can cool down naturally, and the latter movable end can replace the previous movable end to continue the continuous pressurization action, thereby ensuring that the friction material can be stably hot pressed for the second time.

[0082] Preferably, if Figure 2 and Figure 6As shown, the end of the side module 3014 is fixedly connected with a primary connection seat 30145 and a secondary connection seat 30144, and the double-head hydraulic assembly includes a bottom plate 401, a cylinder body 1 402 and a cylinder body 2 403 fixedly connected to the bottom plate 401, a piston 1 and a piston 2 respectively slidably connected in the cylinder body 1 402 and the cylinder body 2 403, a primary piston rod 4021 fixedly connected to the piston 1 and penetrating the cylinder body 1 402, a secondary piston rod 4031 fixedly connected to the piston 2 and penetrating the cylinder body 2 403, a hydraulic cylinder fixedly connected to the top surface of the frame 2 and located in the casing 202, and a hydraulic pump 503, the primary piston rod 4021 and the secondary piston rod 4031 are two movable ends of the double-head hydraulic assembly, and the ends of the primary piston rod 4021 and the secondary piston rod 4031 can be respectively Embedded in the primary connecting seat 30145 and the secondary connecting seat 30144, the cylinder body 1 402 is divided into a primary rear space and a primary front space by piston 1, and the cylinder body 2 403 is divided into a secondary rear space and a secondary front space by piston 2. The primary rear space and the primary front space are respectively connected with a primary oil guide pipe 4061 and a secondary oil guide pipe 4062, and the other ends of the primary oil guide pipe 4061 and the secondary oil guide pipe 4062 are both connected with the hydraulic cylinder, and the hydraulic pump 503 is connected to the primary oil guide pipe 4061 or the secondary oil guide pipe 4062. The primary front space is connected with the secondary rear space through the transmission pipe 1 404, and the primary front space is connected with the secondary front space through the transmission pipe 2 405. The transmission pipe 1 404 and the transmission pipe 2 405 are respectively connected with the solenoid valve 1 4041 and the solenoid valve 2 4051.

[0083] When the two movable ends of the double-head hydraulic assembly need to perform a pressurizing action on the side module 3014 respectively, the first-level piston rod 4021 is first plugged into the first-level connecting seat 30145, and a squeezing force is applied to the side module 3014. At this time, the solenoid valve 1 4041 and the solenoid valve 2 4051 are closed, and the hydraulic pump 503 pumps the hydraulic oil into the first-level rear space, so that the hydraulic oil in the first-level front space leaves through the second-level oil guide pipe 4062, thereby increasing the volume of the first-level rear space and reducing the volume of the first-level front space, so that the first-level piston rod 4021 is driven by the piston 1 to move toward one side of the side module 3014;

[0084] If the heat transfer from the side module 3014 causes the temperature of the rear section of the primary piston rod 4021 to rise somewhere during the secondary hot pressing process, the solenoid valve 1 4041 and the solenoid valve 2 4051 are opened. At this time, the hydraulic pump 503 also works in the reverse direction, and the hydraulic oil enters the primary front space, and then enters the secondary rear space through the transmission pipe 1 404. The hydraulic oil in the secondary front space will enter the primary rear space through the transmission pipe 2 405. In this process, the volume of the primary front space will not reach its maximum before the volume of the secondary rear space reaches its maximum. state, so that during this process, the primary piston rod 4021 will not be separated from the primary connecting seat 30145, but after the secondary piston rod 4031 is plugged into the secondary connecting seat, that is, the secondary piston rod 4031 applies a squeezing force to the side module 3014, and at this time the primary piston rod 4021 moves in the opposite direction, cooperating with the action of the secondary piston rod 4031 pushing the side module 3014, the primary piston rod 4021 is pulled out of the primary connecting seat 30145 on the side module 3014 more smoothly, thereby completing the alternation of the two active ends of the double-head hydraulic assembly.

[0085] Preferably, the double-head hydraulic assembly also includes an electronic control circuit, which collects the temperature of a specific position of the first-stage piston rod 4021 or the second-stage piston rod 4031 and controls the other piston rod to extend to be detachably connected to the end of the side module 3014 after the temperature exceeds a threshold value, and then controls the first-stage piston rod 4021 or the second-stage piston rod 4031 to retract.

[0086] The setting of the electric control circuit enables temperature detection at a certain position on the rear half of the primary piston rod 4021 or the secondary piston rod 4031 as a specific position, and ensures that after the heat transferred from the side module 3014 to the primary piston rod 4021 or the secondary piston rod 4031 reaches a certain level, the connection between the primary piston rod 4021 or the secondary piston rod 4031 and the side module 3014 can be disconnected, allowing the primary piston rod 4021 or the secondary piston rod 4031 to cool down naturally.

[0087] Preferably, if Figure 7 As shown, the electronic control circuit includes

[0088] A temperature sensor 1 40211 is arranged on the mounting seat and its detection end is arranged at a specific position corresponding to the primary piston rod 4021, and collects the temperature at a specific position on the primary piston rod 4021 and feeds back a temperature signal 1;

[0089] A signal amplifying circuit 40212, whose input end is coupled to a temperature sensor 40211, receives a temperature signal 1, amplifies it, and processes it;

[0090] The voltage stabilizing circuit 1 40213, whose input terminal is coupled to the output terminal of the signal amplifying circuit 1 40212, receives the amplified temperature signal and performs voltage stabilizing processing and output;

[0091] A voltage comparison circuit 1 40214, whose input terminal is coupled to the output terminal of the voltage stabilization circuit 1 40213, receives the stabilized temperature signal 1 and issues a first comparison signal when the temperature signal 1 is greater than a preset reference temperature signal 1;

[0092] The second temperature sensor 40311 is arranged on the mounting seat and its detection end is arranged at a specific position corresponding to the secondary piston rod 4031, and collects the temperature at the specific position on the secondary piston rod 4031 and feeds back the second temperature signal;

[0093] The second signal amplifying circuit 40312 has an input end coupled to the second temperature sensor 40311, and receives the second temperature signal and then amplifies and processes it;

[0094] The second voltage stabilizing circuit 40313, whose input terminal is coupled to the output terminal of the second signal amplifying circuit 40312, receives the amplified temperature signal 2 and performs voltage stabilizing processing and output;

[0095] The voltage comparison circuit 3 40314, whose input terminal is coupled to the output terminal of the voltage stabilization circuit 2 40313, receives the stabilized temperature signal 2 and sends out a third comparison signal when the temperature signal 2 is greater than the preset reference temperature signal 2;

[0096] The controller 501, whose input terminal is coupled to the output terminals of the voltage comparison circuit 1 40214 and the voltage comparison circuit 3 40314, receives and issues a control instruction signal in response to the first comparison signal or the third comparison signal;

[0097] A motor controller 502, whose input end is coupled to the output end of the controller 501, and whose output end is coupled to the motor in the hydraulic pump 503;

[0098] The driving circuit 504, the controlled end of the driving circuit 504 is coupled to the output end of the controller 501, the controlled end of the driving circuit 504 is electrically connected, and the solenoid valve 1 4041 and the solenoid valve 2 4051 are connected in series to the controlled end of the driving circuit 504, and the driving circuit 504 controls the solenoid valve 1 4041 and the solenoid valve 2 4051 to be energized when receiving the control command signal.

[0099] Preferably, if Figure 7 As shown, the electric control circuit also includes

[0100] A hydraulic sensor 1 4022, which is fixedly connected to the bottom plate 401 and has a probe extending into the first-stage rear space, collects the hydraulic strength in the first-stage rear space and feeds back a hydraulic signal 1;

[0101] The voltage comparison circuit 2 40221, whose input terminal is coupled to the output terminal of the hydraulic pressure sensor 1 4022, receives the stabilized hydraulic pressure signal 1 and sends a second comparison signal to the controller 501 when the hydraulic pressure signal 1 is greater than the preset reference hydraulic pressure signal 1;

[0102] The second hydraulic sensor 4032 is fixedly connected to the bottom plate 401 and its probe extends into the secondary rear space. It collects the hydraulic strength in the secondary rear space and feeds back the second hydraulic signal;

[0103] The voltage comparison circuit 40321 has its input terminal coupled to the output terminal of the hydraulic sensor 2 4032, receives the stabilized hydraulic signal 2 and sends a fourth comparison signal to the controller 501 when the hydraulic signal 2 is greater than the preset reference hydraulic signal 2.

[0104] In the above, signal amplifying circuit 1 40212 and signal amplifying circuit 2 40312 are both operational amplifiers, voltage stabilizing circuit 1 40213 and voltage stabilizing circuit 2 40313 are both voltage regulators, voltage comparison circuit 1 40214, voltage comparison circuit 2 40221, voltage comparison circuit 3 40314, and voltage comparison circuit 4 40321 all include voltage comparators and resistors, controller 501 is an STM32 single-chip microcomputer, driving circuit 504 is a switching transistor, solenoid valve 1 4041 and solenoid valve 2 4051 are connected in series in the path formed by the collector of the transistor switch and the emitter of the transistor switch, and the base of the transistor switch is coupled to the output end of the controller 501.

[0105] The hydraulic sensor 1 4022 and the hydraulic sensor 2 4032 are set mainly to collect the hydraulic conditions in the cylinder body 1 402 and the cylinder body 2 403, specifically to detect the hydraulic strength in the first-stage rear space and the second-stage rear space. When the force applied by the first-stage piston rod 4021 to the side module 3014 meets the requirements, the hydraulic oil in the first-stage rear space will also have corresponding hydraulic pressure. At this time, the hydraulic sensor 1 4022 feeds back the hydraulic signal 1 to the voltage comparison circuit 2 40221 for comparison, and sends a signal to the controller 501 after judging that it meets the requirements, and the controller 501 sends an instruction to the motor controller 502, thereby stopping the hydraulic pressure. The pressure pump 503 works. Similarly, when the force applied by the secondary piston rod 4031 to the side module 3014 meets the requirements, the hydraulic oil in the secondary rear space will also have corresponding hydraulic pressure. At this time, the hydraulic sensor 2 4032 feeds back the hydraulic signal 2 to the voltage comparison circuit 40321 for comparison, and sends a signal to the controller 501 after judging that it meets the requirements. The controller 501 cuts off the power to the solenoid valve 1 4041 and the solenoid valve 2 4051 through the drive circuit 504, so that the transmission pipe 1 404 and the transmission pipe 2 405 are closed, so as to maintain the squeezing state of the secondary piston rod 4031 on the side module 3014.

[0106] In summary, the present invention can form a friction material attached to the backing steel, and the connection can be completed without the burr structure on the backing steel piercing into the friction material, thereby ensuring the connection strength between the two and improving the shear strength after the connection.

[0107] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A bicycle brake disc forming process, characterized in that: The following steps are included: Prepare materials: weigh Nao friction raw materials and mix them to form Nao friction materials; Equipment debugging, adjusting the cross-sectional area of ​​the molding cavity (3012) in the middle and lower mold (301) of the hot press to be larger than the area of ​​the reference friction lining (1), and the length of the molding cavity (3012) in the middle and lower mold (301) of the hot press to be larger than the length of the reference friction lining (1); Feeding the Nao friction material in batches, twice, into a molding cavity (3012) in a middle and lower mold (301) of a hot press, and laying two symmetrical and U-shaped copper-nickel alloy resistance wires (101) between the two Nao friction materials; In the initial hot pressing, a backing steel is placed above the molding cavity (3012) in the lower mold (301) of the hot press, and then heated and pressed down into the molding cavity (3012) by the upper mold (302) of the hot press to compact and mold the Nao friction material, at which time the distance between the backing steel and the bottom surface of the molding cavity (3012) is greater than the thickness of the reference friction lining (1); Secondary hot pressing, the cross-sectional area of ​​the molding cavity (3012) in the middle and lower mold (301) of the hot press is adjusted back to the area of ​​the reference friction lining (1), the length of the molding cavity (3012) in the middle and lower mold (301) of the hot press is adjusted back to the length of the reference friction lining (1), and the middle and lower mold (301) of the hot press is energized to the copper-nickel alloy resistance wire (101) in the length direction of the molding cavity (3012), so that the copper-nickel alloy resistance wire (101) heats the interior of the Nao friction material; Three hot pressings, the upper mold (302) in the hot pressing machine is continuously heated and pressed down twice, at which time the distance between the back steel and the inner bottom surface of the molding cavity (3012) is equal to the thickness of the reference friction lining (1); Demolding, the upper mold (302) in the hot press is reset, and the length of the molding cavity (3012) in the lower mold (301) in the hot press is restored to be greater than the length of the reference friction lining (1), and then the friction lining (1) and the backing steel after hot pressing are removed from the molding cavity (3012) in the length direction and demolded; The product is produced by cutting off the copper-nickel alloy resistance wires (101) protruding at both ends of the friction lining (1) in the length direction, and cooling the friction lining (1) and the backing steel to room temperature to obtain a finished friction lining (1) and the backing steel; The hot press comprises a frame (2), a workbench (201) fixedly connected to the frame (2), a lower mold (301) detachably connected to the top surface of the workbench (201), an upper mold (302) movable in a lifting manner in the frame (2), a lower heating wire (3011) arranged in the lower mold (301), and an upper heating wire (3021) arranged in the upper mold (302), wherein the lower heating wire (3011) and the upper heating wire (3021) can be switched on and off, the top surface of the lower mold (301) is recessed downward to form a molding cavity (3012), and the top surface of the lower mold (301) is recessed downward to form a slide groove (3012) communicating with the end of the molding cavity (3012) in the length direction and penetrating the side wall of the lower mold (301). 3013), a side module (3014) is slidably connected in the slide groove (3013), the spacing between the side modules (3014) on both sides is adjusted to change the length of the molding cavity (3012), and the side modules (3014) located at the inner wall of the molding cavity (3012) are provided with a shrinking groove (30141) for inserting two ends of the copper-nickel alloy resistance wire (101), and a through hole penetrating the side module (3014) is provided at the end of the shrinking groove (30141), and a copper sleeve (30142) arranged in contact with the inner wall of the shrinking groove (30141) is fixedly connected, and a wire (30146) penetrating the through hole is fixedly connected to the copper sleeve (30142), and the wire (30146) is connected to a power supply; The hot press also includes a casing (202) fixedly connected to the top surface of the frame (2), a hydraulic cylinder fixedly connected to the top surface of the frame (2) and located inside the casing (202), the top surface of the workbench (201) is fixedly connected to a plurality of guide columns (203) fixedly connected to the inner top surface of the frame (2), a connecting plate (204) is slidably connected to the plurality of guide columns (203), the upper mold (302) is fixedly connected to the bottom surface of the connecting plate (204), and a hydraulic rod of the hydraulic cylinder penetrates the top surface of the frame (2) and is fixedly connected to the top surface of the connecting plate (204); The hot press also includes two groups of double-headed hydraulic components for controlling the displacement of the side modules (3014); the double-headed hydraulic components are fixedly connected to the side wall of the frame (2) via a mounting frame (4); and the double-headed hydraulic components have two movable ends, both of which are detachably connected to the end of the side module (3014); and the two movable ends of the double-headed hydraulic components are alternately connected to the end of the side module (3014); when the two movable ends of the double-headed hydraulic components are alternately connected, the detachable connection state with the end of the side module (3014) is released until the previous movable end is completely detachably connected to the end of the side module (3014); The end of the side module (3014) is fixedly connected to a primary connection seat (30145) and a secondary connection seat (30144). The double-head hydraulic assembly comprises a base plate (401), a cylinder body 1 (402) and a cylinder body 2 (403) fixedly connected to the base plate (401), a piston 1 and a piston 2 respectively slidably connected to the cylinder body 1 (402) and the cylinder body 2 (403), a primary piston rod (4021) fixedly connected to the piston 1 and penetrating the cylinder body 1 (402), a secondary piston rod (4031) fixedly connected to the piston 2 and penetrating the cylinder body 2 (403), a hydraulic cylinder fixedly connected to the top surface of the frame (2) and located in the casing (202), and a hydraulic pump (503). The primary piston rod (4021) and the secondary piston rod (4031) are two movable ends of the double-head hydraulic assembly. The ends of the primary piston rod (4021) and the secondary piston rod (4031) can be respectively embedded in the cylinder body 1 (402) and the cylinder body 2 (403). To the first-stage connecting seat (30145) and the second-stage connecting seat (30144), the cylinder body (402) is divided into a first-stage rear space and a first-stage front space by a piston (1), and the cylinder body (403) is divided into a second-stage rear space and a second-stage front space by a piston (2), and the first-stage rear space and the first-stage front space are respectively connected to a first-stage oil guide pipe (4061) and a second-stage oil guide pipe (4062), and the first-stage oil guide pipe (4061) and the second-stage oil guide pipe (4062) are respectively connected to each other. ) are connected to the hydraulic cylinder, the hydraulic pump (503) is connected to the primary oil guide pipe (4061) or the secondary oil guide pipe (4062), the primary front space is connected to the secondary rear space through the transmission pipe 1 (404), the primary front space is connected to the secondary front space through the transmission pipe 2 (405), and the transmission pipe 1 (404) and the transmission pipe 2 (405) are respectively connected to the electromagnetic valve 1 (4041) and the electromagnetic valve 2 (4051).

2. A bicycle brake disc forming process according to claim 1, characterized in that: The batch feeding also includes the setting that the amount of Nao friction material fed twice is the same.

3. A bicycle brake disc forming process according to claim 1 or 2, characterized in that: When the copper-nickel alloy resistance wire (101) is laid between the two Nao friction materials, the two ends of the copper-nickel alloy resistance are arranged to protrude from the edge of the Nao friction material.

4. A bicycle brake disc forming process according to claim 1, characterized in that: The double-head hydraulic assembly also includes an electric control circuit, which collects the temperature of the position to be detected of the first-stage piston rod (4021) or the second-stage piston rod (4031) and controls the other piston rod to extend to a removable connection with the end of the side module (3014) after the temperature exceeds a threshold value, and then controls the first-stage piston rod (4021) or the second-stage piston rod (4031) to retract.

5. A bicycle brake disc forming process according to claim 4, characterized in that: The electric control circuit comprises A temperature sensor 1 (40211) is arranged on the mounting seat and its detection end is arranged corresponding to the position to be detected of the primary piston rod (4021), and collects the temperature of the position to be detected on the primary piston rod (4021) and feeds back a temperature signal 1; A signal amplifying circuit 1 (40212), whose input end is coupled to a temperature sensor 1 (40211), receives a temperature signal 1, amplifies it and processes it; The voltage stabilizing circuit 1 (40213) has an input end coupled to the output end of the signal amplifying circuit 1 (40212), and receives the amplified temperature signal and performs voltage stabilizing processing and output; A voltage comparison circuit 1 (40214), whose input end is coupled to the output end of the voltage stabilization circuit 1 (40213), receives the stabilized temperature signal 1 and sends a first comparison signal when the temperature signal 1 is greater than a preset reference temperature signal 1; A second temperature sensor (40311) is arranged on the mounting seat and its detection end is arranged corresponding to the position to be detected of the secondary piston rod (4031), and collects the temperature of the position to be detected on the secondary piston rod (4031) and feeds back a second temperature signal; The second signal amplifying circuit (40312) has an input end coupled to the second temperature sensor (40311) and receives the second temperature signal and then amplifies and processes it; The second voltage stabilizing circuit (40313) has an input end coupled to the output end of the second signal amplifying circuit (40312), receives the amplified temperature signal 2 and performs voltage stabilization processing and output; A voltage comparison circuit 3 (40314), whose input end is coupled to the output end of the voltage stabilization circuit 2 (40313), receives the stabilized temperature signal 2 and sends a third comparison signal when the temperature signal 2 is greater than a preset reference temperature signal 2; A controller (501), whose input end is coupled to the output ends of the voltage comparison circuit 1 (40214) and the voltage comparison circuit 3 (40314), and which receives and issues a control instruction signal in response to the first comparison signal or the third comparison signal; A motor controller (502), an input end of which is coupled to an output end of the controller (501), and an output end of the motor controller (502) is coupled to a motor in a hydraulic pump (503); A drive circuit (504), wherein a controlled end of the drive circuit (504) is coupled to an output end of a controller (501), the controlled end of the drive circuit (504) is electrically connected, and the solenoid valve 1 (4041) and the solenoid valve 2 (4051) are connected in series to the controlled end of the drive circuit (504), and when the drive circuit (504) receives a control command signal, it controls the solenoid valve 1 (4041) and the solenoid valve 2 (4051) to be energized.

6. A bicycle brake disc forming process according to claim 5, characterized in that: The electric control circuit also includes A hydraulic sensor 1 (4022), wherein the hydraulic sensor 1 (4022) is fixedly connected to the bottom plate (401) and its probe extends into the first-stage rear space, and collects the hydraulic intensity in the first-stage rear space and feeds back a hydraulic signal 1; A voltage comparison circuit 2 (40221), whose input end is coupled to the output end of the hydraulic sensor 1 (4022), receives the stabilized hydraulic signal 1 and sends a second comparison signal to the controller (501) when the hydraulic signal 1 is greater than a preset reference hydraulic signal 1; A second hydraulic sensor (4032), the second hydraulic sensor (4032) is fixedly connected to the bottom plate (401) and its probe extends into the secondary rear space, and collects the hydraulic intensity in the secondary rear space and feeds back a second hydraulic signal; The voltage comparison circuit 4 (40321) has an input end coupled to the output end of the hydraulic sensor 2 (4032), receives the stabilized hydraulic signal 2 and sends a fourth comparison signal to the controller (501) when the hydraulic signal 2 is greater than the preset reference hydraulic signal 2.

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