Servo prepressing forming device and method for double-layer powder material

Abstract

The invention discloses a double-layer powder material servo prepressing forming device and method, and belongs to the technical field of powder metallurgy forming. A set of built-in servo driving mechanism is additionally arranged on a traditional forming upper punching mechanism, a set of movable pre-pressing upper punching mechanism is additionally arranged, after first-time powder filling is completed, the forming upper punching mechanism stops at the first position, at the moment, the pre-pressing upper punching mechanism conveys a pre-pressing upper punch to the upper side of a die cavity, and through control of a servo motor, the forming upper punching mechanism stops at the first position; the driving rod moves downwards to make contact with the pre-pressing upper punching mechanism, the pre-pressing upper punching head is pressed into the die cavity, the needed interlayer interface shape is pressed, then the driving rod and the pre-pressing upper punching head retreat, secondary powder filling is conducted, and the forming upper punching head enters the die cavity to conduct final forming pressing. Step-by-step powder filling and step-by-step pressing are achieved in one working cycle of the forming upper punching mechanism, the requirement that the interlayer interface shape of a final product can be set is met, operation is easy and convenient, the application range is wide, and the method can be popularized to various powder metallurgy devices.

Description

TECHNICAL FIELD

[0001] The present application relates to a double-layer powder material servo pre-press forming device and method, and belongs to the technical field of powder metallurgy forming. BACKGROUND

[0002] In the existing mechanical powder metallurgy forming technology, a general device usually includes a crank slider mechanism, a forming upper punch mechanism, a forming middle die mechanism, a forming lower punch mechanism, a forming core rod mechanism, and a powder feeding mechanism, wherein the working principle between the crank slider mechanism and the forming upper punch mechanism is that the forming upper punch mechanism is driven by the crank slider mechanism to move downward along a fixed track from the top (upper dead point) to the bottom (lower dead point), thereby completing a one-way pressing action.

[0003] This structure has inherent limitations: due to the limitation of the single and continuous downward movement characteristics of the crank slider mechanism, the forming upper punch mechanism can only perform a continuous and one-way pressing action in one working cycle. Therefore, the existing device can only realize a "one-time pressing" action.

[0004] However, with the continuous development of powder metallurgy products, the market demand for double-layer (or more than two layers) powder metallurgy products is increasing. For such special products, two (or more than two) times of powder filling are required, and after each powder filling, the filled powder material needs to be pressed once, that is, two (or more than two) times of pressing action is required. Obviously, the existing general powder metallurgy forming device cannot realize this action.

[0005] Therefore, there is an urgent need in the art for an innovative forming device that not only can realize two (or more than two) times of powder filling, but also can meet the requirement of completing two (or more than two) times of pressing action in one working cycle of the forming upper punch mechanism, thereby meeting the production demand of double-layer (or more than two layers) powder metallurgy products. SUMMARY

[0006] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide a double-layer powder material servo pre-press forming device and method with simple and reasonable structure, which can realize step-by-step powder filling and step-by-step pressing in one working cycle of the forming upper punch mechanism, and meet the production demand of double-layer (or more than two layers) powder metallurgy products.

[0007] The technical solution of the present application is as follows: The first purpose of the present application is to provide a double-layer powder material servo pre-press forming device, which comprises a rack, a forming upper punch mechanism, a forming middle die mechanism, a forming lower punch mechanism, a forming core rod mechanism, and a powder feeding mechanism arranged on the rack, characterized in that it further comprises a pre-press upper punch mechanism, a displacement mechanism, and a servo drive mechanism; wherein: The pre-pressing upper punch mechanism comprises a pre-pressing upper punch, and a displacement mechanism connected to the pre-pressing upper punch mechanism for driving the pre-pressing upper punch mechanism to move between a pre-pressing position and a avoiding position above the die cavity of the forming upper punch mechanism; a servo driving mechanism is installed on the forming upper punch mechanism and moves synchronously therewith; the servo driving mechanism comprises a power mechanism and a driving rod driven by the power mechanism; The powder feeding mechanism comprises a first powder feeding mechanism and a second powder feeding mechanism for feeding the first powder metallurgy material and the second powder metallurgy material into the die cavity of the forming upper punch mechanism in sequence; When the forming upper punch mechanism is lowered to the first position and the pre-pressing upper punch mechanism is located at the pre-pressing position, the driving power mechanism is driven to make the driving rod engage with the pre-pressing upper punch mechanism and drive the pre-pressing upper punch to lower, thereby completing the pre-pressing of the first powder metallurgy material; then the forming upper punch mechanism is continuously lowered to the second position, thereby completing the forming and pressing of the double-layer powder metallurgy material.

[0008] The above scheme can be used for a double-layer structure powder metallurgy product, and after the first powder filling is completed, the first powder metallurgy material is pre-pressed by the pre-pressing upper punch mechanism once to obtain a required pre-pressing surface state, and then the forming upper punch mechanism is used to perform forming and pressing of the second powder filling.

[0009] By integrating a servo driving mechanism which can move synchronously on the traditional forming upper punch mechanism and cooperating with the movable pre-pressing upper punch mechanism, the equipment can realize twice powder filling and twice pressing in one working cycle of the forming upper punch mechanism. After the first layer of powder metallurgy material is filled, the first layer of powder metallurgy material is precisely pre-pressed, thereby ensuring the density, thickness and pre-pressing surface state of the first layer of powder metallurgy material, preventing the mixing of the layers of materials and enhancing the bonding force between the layers.

[0010] Preferably, the pre-pressing upper punch mechanism further comprises an upper pressing plate, a lower pressing plate, four pre-pressing guide rods and four springs, wherein: The upper pressing plate is used for engaging with the driving rod, and the pre-pressing upper punch is fixedly installed at the bottom of the upper pressing plate; The lower pressing plate is arranged in parallel below the upper pressing plate and is connected with the displacement mechanism, and the lower pressing plate is provided with an avoiding opening through which the pre-pressing upper punch passes; The four pre-pressing guide rods are fixedly connected with the four top corners of the lower pressing plate respectively, and the top portions of the four pre-pressing guide rods pass through the upper pressing plate and are slidably connected with the upper pressing plate; The four springs are respectively sleeved on the four pre-pressing guide rods and are compressed between the upper pressing plate and the lower pressing plate.

[0011] The above scheme enables the pre-pressing upper punch to have a buffering capacity during contacting the powder and pressing, and the spring can ensure that the pre-pressing upper punch is automatically reset after the pre-pressing is completed.

[0012] Preferably, the top of the upper pressing plate is provided with an engaging head matched with the driving rod, and the top of the engaging head is provided with an insertion hole matched with the end of the driving rod. The matching of the engaging head and the insertion hole provides a precise and reliable docking interface for the driving rod and the pre-pressing upper punch mechanism, ensuring accurate and efficient power transmission.

[0013] Preferably, the end of the driving rod is in the shape of a circular truncated cone, forming a guide cone surface to facilitate quick and smooth introduction into the insertion hole.

[0014] Preferably, the four pre-pressing guide rods are in two groups, and the top ends of the pre-pressing guide rods in each group are connected by a limiting connecting rod, ensuring the synchronization of the up and down displacement of the pre-pressing guide rods and preventing the pre-pressing guide rods from disengaging from the upper pressing plate.

[0015] The working steps of the pre-pressing upper punch mechanism are as follows: (1) When the driving rod of the servo driving mechanism is lowered and engaged with the engaging head (insertion hole) of the upper pressing plate, the driving rod continues to descend, transmitting driving force to the upper pressing plate. (2) The driving rod pushes the upper pressing plate to move downward relative to the lower pressing plate along the guidance of the four pre-pressing guide rods, overcoming the spring force. (3) The pre-pressing upper punch fixedly installed at the bottom of the upper pressing plate is lowered synchronously, passes through the avoiding opening of the lower pressing plate, and accurately enters the mold cavity of the forming die mechanism, pre-pressing the filled first powder metallurgy material. (4) After pre-pressing is completed, the driving rod ascends; at this time, the released spring force pushes the upper pressing plate and the pre-pressing upper punch to move upward along the pre-pressing guide rods, automatically resetting to the initial position.

[0016] Preferably, the displacement mechanism comprises a linear module, a ball guide seat, a displacement guide rod, and a pressing mechanism. The linear module comprises a sliding block, and the ball guide seat is fixedly installed on the base of the linear module and is provided with a through ball guide hole. The displacement guide rod passes through the ball guide hole (realizing precise guide positioning) and is connected to the pre-pressing upper punch mechanism at one end. The pressing mechanism is connected to the sliding block and the pre-pressing upper punch mechanism respectively to drive the pre-pressing upper punch mechanism to displace along the ball guide seat and make the pre-pressing upper punch mechanism closely adhere to the powder feeding panel.

[0017] In the above scheme, the linear module ensures the movement precision of the pre-pressing upper punch mechanism between the pre-pressing station and the avoiding station. The pressing mechanism can ensure that the entire pre-pressing upper punch mechanism closely adheres to the powder feeding panel during pre-pressing, improving the stability of the pre-pressing upper punch mechanism.

[0018] Preferably, the pressing mechanism comprises a pair of pressing rods, a pair of supporting rods, and a pair of pressing cylinders, wherein: The pair of pressing rods are arranged in parallel and symmetry, and the lower ends of the pressing rods are respectively connected to the pre-pressing and upward thrust mechanism; The pair of supporting rods are arranged in parallel and symmetry, and the top ends of the supporting rods are respectively rotatably connected to the pair of pressing rods, and the bottom ends of the supporting rods are respectively fixedly connected to the sliding block through a support; The pair of pressing cylinders are arranged in parallel and symmetry, and the piston rods of the pressing cylinders are respectively rotatably connected to the higher ends of the pair of pressing rods, and the cylinder bottoms of the pressing cylinders are respectively fixedly connected to the support.

[0019] The above scheme enables the pair of pressing rods to rotate around the top ends of the corresponding supporting rods through the extension and retraction of the pair of pressing cylinders, so as to press or release the pre-pressing and upward thrust mechanism, thereby improving the stability of the pre-pressing and upward thrust mechanism during the pre-pressing process.

[0020] Preferably, the two side walls of the lower pressing plate are respectively provided with positioning pins, and the lower ends of the pair of pressing rods are respectively provided with clamping grooves matched with the positioning pins in shape, and the clamping grooves of the pressing rods are clamped and connected with the corresponding positioning pins.

[0021] Preferably, the positioning pins are made of polyurethane material and have a certain elasticity, so as to adjust the positional difference between the pre-pressing and upward thrust mechanism and the driving rod. Even if there is a slight positional deviation between the abutting axis of the driving rod and the pre-pressing and upward thrust mechanism (the insertion hole of the joint head), the positioning pin can also be moderately elastically deformed under the pressure of the clamping groove, so as to enable the driving rod to smoothly enter the insertion hole.

[0022] Preferably, the servo driving mechanism further comprises a servo motor, a housing, and a worm, a worm wheel, a nut, a lead screw and a driving plate located in the housing, wherein: The housing is mounted on the fixed plate of the forming and upward thrust mechanism, and the servo motor is mounted on the housing; The worm is drivingly connected with the output shaft of the servo motor, the worm wheel is drivingly connected with the worm in meshing mode and is provided with a central hole, the nut is fixedly installed in the central hole of the worm wheel and is provided with a central threaded hole, and the lead screw is threadedly connected in the central threaded hole of the nut; The driving plate is fixedly connected with the lead screw and is used for mounting the driving rod, and the driving rod penetrates through the fixed plate of the forming and upward thrust mechanism.

[0023] The servo motor drives the worm, drives the worm wheel and the nut to rotate, and then drives the lead screw to move up and down, so as to realize the upward or downward movement of the driving rod. The worm and the worm wheel have a self-locking function, can meet the pressure maintaining requirement of the pre-pressing process, and have a compact structure, a large transmission ratio and a high output torque.

[0024] Preferably, the first powder feeding mechanism and the second powder feeding mechanism each comprises a powder box and a corresponding driving device. Although the powder box is always tightly attached to the powder feeding panel during powder feeding, some powder may be inevitably left on the surface of the middle mold and the surface of the powder feeding panel. If the left powder of the previous layer is not cleaned in time, it will affect the distribution of the next layer of powder, and even mix into the next layer of powder material, destroy the purity of the interface between layers, and affect the interface bonding strength, mechanical properties and product quality of the composite product.

[0025] Therefore, a negative pressure cavity can be arranged inside the powder box of the first powder feeding mechanism and the second powder feeding mechanism, the bottom of the negative pressure cavity is open and attached to the powder feeding panel, the negative pressure cavity is arranged on the front side of the powder box cavity and connected to a dust collection device. When the powder box retreats, the powder left near the mold cavity and on the powder feeding panel is immediately sucked by negative pressure, avoiding interference between the layers of powder.

[0026] Preferably, the device further comprises a material taking mechanism, which comprises a servo sliding table, a material channel mounted on the rack, and a material taking lever. The material taking lever is connected to the servo sliding table and is provided with a material taking groove matched with the shape of the pressed blank, so as to automatically take out the pressed blank after demolding.

[0027] Preferably, the first powder feeding mechanism and the second powder feeding mechanism are arranged on opposite sides of the forming middle mold mechanism, and the displacement mechanism (pre-pressing upper punch mechanism) and the material taking mechanism are arranged on the other opposite sides of the forming middle mold mechanism. The space structure is optimized, and the execution mechanisms do not interfere with each other.

[0028] Preferably, the rack is provided with a dust collecting hopper at the corresponding positions of the first powder feeding mechanism, the second powder feeding mechanism, the displacement mechanism (pre-pressing upper punch mechanism) and the material taking mechanism. Each dust collecting hopper is located below the moving path of the corresponding execution mechanism, and is used to collect excess dust falling during displacement.

[0029] Preferably, the end of the pre-pressing upper punch is in the shape of a circular truncated cone, so that the pre-pressing surface of the first powder metallurgy material forms a conical surface (the cross section of the pre-pressing surface is a slanted line). This not only facilitates the filling of the second layer of powder, but also enhances the interlayer bonding strength, meeting the requirements of the shape of the interface between layers of the final product.

[0030] The second object of the present application is to provide a double-layer powder material servo pre-pressing forming method using the above device, characterized by comprising the following steps: (1) driving the first powder feeding mechanism to move forward on the powder feeding panel, and feeding the first powder metallurgy material into the mold cavity of the forming middle mold mechanism. After powder feeding is completed, the first powder feeding mechanism is driven to move backward to reset; (2) driving the forming upper punch mechanism to move downward to the first position, and the servo driving mechanism moves downward at the same time; (3) The displacement mechanism works to drive the pre-pressing upper punch mechanism to move forward to a pre-pressing station; (4) The power mechanism works to make the driving rod move downward and engage with the pre-pressing upper punch mechanism (the driving rod enters the insertion hole of the corresponding engagement head), the driving rod continues to move downward and drives the pre-pressing upper punch to move downward, the pre-pressing upper punch enters the mold cavity, the first powder metallurgy material in the mold cavity is pre-pressed by the pre-pressing upper punch to form a first powder metallurgy material layer, and a pre-pressing surface is formed on the surface of the first powder metallurgy material layer; (5) The power mechanism drives the driving rod to move upward to reset, the pre-pressing upper punch moves upward to reset under the action of the spring; the displacement mechanism works to drive the pre-pressing upper punch mechanism to move backward to a avoiding station; (6) The second powder feeding mechanism is driven to move forward on the powder feeding panel to feed the second powder metallurgy material into the mold cavity of the forming middle die mechanism, and after the powder feeding is completed, the second powder feeding mechanism is driven to move backward to reset; (7) The forming upper punch mechanism is driven to continue to move downward to a second position, the forming upper punch enters the mold cavity, and the first and second powder metallurgy materials in the mold cavity are pressed by the forming upper punch to obtain a pressed and formed double-layer structure powder metallurgy material compact; The servo sliding table works to move the material taking lever forward to the side of the mold cavity and opposite to the first powder feeding mechanism; (8) The forming upper punch mechanism is driven to move upward to reset; under the cooperation of the forming middle die mechanism, the forming core rod mechanism and the forming lower punch mechanism, the formed compact is ejected out of the mold cavity; (9) The production of the next batch of compacts is entered, and in the process of moving the first powder feeding mechanism forward to the mold cavity to feed powder, the first powder feeding mechanism pushes the formed compact into the material taking groove of the material taking lever; The servo sliding table controls the material taking lever to reset, and the material taking lever feeds the compact into the material channel.

[0031] Preferably, two independent mold cavities are arranged in the forming middle die mechanism, two pre-pressing upper punches are arranged in the pre-pressing upper punch mechanism, two forming upper punches are arranged at the bottom of the forming upper punch mechanism, and two material taking grooves are arranged on the material taking lever, so that two compacts are formed at one time, i.e. two compacts are formed at one time.

[0032] Preferably, when the crank of the crank slider mechanism rotates from the top dead center (0° position) to the interval of 30°-60°, the forming punch mechanism driven by the crank slider mechanism descends to the first position, at which the forming punch mechanism can avoid interference with the pre-pressing punch mechanism, and the servo driving mechanism can be sent to the right working height so as to engage the driving rod with the pre-pressing punch mechanism. The length of the driving rod does not need to be too long, and the descending time of the driving rod can be saved, and the production efficiency is improved. When the crank of the crank slider mechanism rotates to the bottom dead center (180°), the forming punch mechanism driven by the crank slider mechanism descends to the lowest end of the stroke, i.e. the second position, at which the pressing and forming of all powder materials are completed.

[0033] Preferably, according to the layer requirement of the powder metallurgy product, a proper number of powder feeding mechanisms are arranged, and the space is optimized according to the actual installation condition, and meanwhile, the corresponding multiple pre-pressing positions of the driving rod in the descending process are adaptively arranged. By cooperation of the servo driving mechanism and the movable pre-pressing punch mechanism, (n-1) layers of powder materials are sequentially pre-pressed (n≥2), and all the materials are pressed and formed by the forming punch mechanism acting on the nth layer of materials, so as to form a green compact.

[0034] The present application adds a set of built-in servo driving mechanism to the conventional forming punch mechanism, and adds a set of movable pre-pressing punch mechanism. After the first powder filling is completed, the forming punch mechanism stops at the first position, at which the pre-pressing punch mechanism sends the pre-pressing punch head to the upper side of the mold cavity. By control of the servo motor, the driving rod moves downward to contact the pre-pressing punch mechanism, so as to press the pre-pressing punch head into the mold cavity to press the required interlayer interface shape. Then the driving rod and the pre-pressing punch head retreat, and the second powder filling is performed, and the forming punch head enters the mold cavity to perform the final pressing and forming.

[0035] The present application has novel mechanism structure, exquisite principle, and wide application range. In one working cycle of the forming punch mechanism, the step-by-step powder filling and step-by-step pressing are realized, and the requirement of setting the interlayer interface shape of the final product is met. The present application is simple in operation and wide in application range, and can be popularized to various powder metallurgy equipment. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 FIG. 1 is a structural schematic view of the double-layer powder material servo pre-pressing forming device of the present application (the pre-pressing punch mechanism is in the avoiding position); Figure 2 FIG. 2 is a top view of the double-layer powder material servo pre-pressing forming device of the present application; Figure 1 Figure 3 FIG. 3 is a structural schematic view of the double-layer powder material servo pre-pressing forming device of the present application (the forming punch mechanism, the powder feeding mechanism and the like are not shown, and the pre-pressing punch mechanism is in the pre-pressing position); Figure 4 FIG. 4 is a structural schematic view of the displacement mechanism in the present application.​ Figure 5 Structure diagram of pre-pressing upper punch mechanism in the application; Figure 6 Structure diagram of pre-pressing upper punch mechanism in the application (number of upper punches is two); Figure 7 Installation diagram of servo driving mechanism and forming upper punch mechanism in the application (number of upper punches is two); Figure 8 Cross-sectional view of Figure 7 ; Figure 9 Structure diagram of material taking mechanism in the application; Figure 10 Structure diagram of powder box of first or second powder feeding mechanism in the application; Figure 11 Structure diagram of valve seat ring in Example 3; In the figure: forming upper punch mechanism 10, forming upper punch 11, fixed plate 12; Forming die mechanism 20, die cavity 21; Forming lower punch mechanism 30, forming core rod mechanism 31; Powder feeding panel 40, first powder feeding mechanism 41, second powder feeding mechanism 42, powder box material cavity 43, negative pressure cavity 44; Pre-pressing upper punch mechanism 50, upper pressing plate 51, lower pressing plate 52, avoiding port 521, positioning pin 522, pre-pressing guide rod 53, spring 54, pre-pressing upper punch 55, engaging head 56, insertion hole 561, limiting connecting rod 57; Displacement mechanism 60, linear module 61, sliding block 611, base 612, ball guide seat 62, displacement guide rod 63, pressing rod 64, supporting rod 65, pressing cylinder 66, support 67; Servo driving mechanism 70, driving rod 71, servo motor 72, shell 73, worm 74, worm gear 75, nut 76, screw rod 77, driving plate 78; Material taking mechanism 80, servo sliding table 81, material channel 82, material taking lever 83, material taking groove 831; Dust collecting hopper 90; Main working area 101, secondary working area 102. DETAILED DESCRIPTION

[0037] Example 1 Double-layer powder material servo pre-pressing forming device, such as Figures 1-3As shown, the assembly includes a frame, a forming upper punch mechanism 10 mounted on the frame, a forming middle die mechanism 20, a forming lower punch mechanism 30, a forming mandrel mechanism 31, a powder feeding mechanism, a pre-pressing upper punch mechanism 50, a displacement mechanism 60, a servo drive mechanism 70, and a material handling mechanism 80. The forming upper punch mechanism 10 includes a forming upper punch head 11 and a fixing plate 12, and the forming middle die mechanism 20 includes a die cavity 21.

[0038] 1. Powder delivery organization Powder delivery organizations, such as Figure 1 As shown, it includes: a powder feeding panel 40, a first powder feeding mechanism 41 and a second powder feeding mechanism 42, which are used to sequentially feed the first powder metallurgy material and the second powder metallurgy material into the mold cavity 21 of the forming mold mechanism 20.

[0039] Preferably, both the first powder feeding mechanism 41 and the second powder feeding mechanism 42 include: a powder box and a corresponding driving device. For example... Figure 10 As shown, a negative pressure chamber 44 is provided inside the powder box. The bottom of the negative pressure chamber is open and fits against the powder feeding panel. The negative pressure chamber is located on the front side of the powder box material cavity 43 and is connected to a dust collection device. When the powder box retracts, it immediately performs negative pressure suction to draw out the powder remaining near the mold cavity opening and on the powder feeding panel.

[0040] 2. Pre-stressing upward punching mechanism Preload upward punching mechanism 50, such as Figure 5 As shown, it includes: an upper pressure plate 51, a lower pressure plate 52, four pre-pressure guide rods 53, four springs 54, and a pre-pressure upper punch 55.

[0041] The pre-pressing upper punch 55 is fixedly installed at the bottom of the upper pressure plate 51; the lower pressure plate 52 is arranged parallel to the lower part of the upper pressure plate 51 for connection with the displacement mechanism 60, and the lower pressure plate 52 is provided with a clearance opening 521 to facilitate the passage of the pre-pressing upper punch 55.

[0042] The bottom of the four pre-compression guide rods 53 are fixedly connected to the four top corners of the lower pressure plate 52, and the top of the four pre-compression guide rods 53 pass through the upper pressure plate 51 and are slidably connected to the upper pressure plate 51. The four pre-compression guide rods 53 are in pairs, and the top of each pair of pre-compression guide rods are connected by a limiting link 57.

[0043] Four springs 54 are respectively sleeved on the four preloaded guide rods 53 and compressed between the upper and lower pressure plates.

[0044] The top of the upper pressure plate 51 is provided with a coupling head 56 that mates with the drive rod, and the top of the coupling head is provided with an insertion hole 561 that mates with the end of the drive rod 71.

[0045] During work: (1) When the drive rod 71 of the servo drive mechanism moves down and engages with the coupling head 56 (insertion hole 561), the drive rod 71 continues to move down and transmits the driving force to the upper pressure plate 51. (2) The drive rod 71 pushes the upper pressure plate 51 to overcome the spring force and move downward relative to the lower pressure plate 52 along the guide of the four pre-pressed guide rods 53; (3) The pre-pressing upper punch 55, which is fixedly installed at the bottom of the upper pressure plate 51, moves down synchronously, passes through the clearance opening 521 of the lower pressure plate 52, and precisely enters the mold cavity 21 of the forming middle mold mechanism to pre-press the filled first powder metallurgy material. (4) After the pre-pressing is completed, the drive rod 71 moves upward; at this time, the compressed spring 54 releases its elastic force, pushing the upper pressure plate 51 and the pre-pressing upper punch 55 to move upward along the pre-pressing guide rod 53 and automatically reset to the initial position.

[0046] 3. Displacement mechanism Displacement mechanism 60, such as Figure 4 As shown, it includes: a linear module 61, a ball bearing guide seat 62, a displacement guide rod 63, a pair of parallel and symmetrically arranged clamping rods 64, a pair of parallel and symmetrically arranged support rods 65, a pair of parallel and symmetrically arranged clamping cylinders 66, and a bracket 67.

[0047] The linear module includes a slider 611 and a base 612. A ball bearing guide seat 62 is fixedly installed on the base 612 of the linear module and has a through ball bearing guide hole. A displacement guide rod 63 passes through the ball bearing guide hole, and one end of its end is connected to the lower pressure plate 52 of the pre-pressing upper punch mechanism. The displacement guide rod and the ball bearing guide seat cooperate to achieve precise guidance and positioning of the pre-pressing upper punch mechanism.

[0048] The lower pressure plate 52 has positioning pins 522 on both sides. The lower end of a pair of clamping rods 64 is provided with a slot that matches the shape of the positioning pin. The slot of the clamping rod 64 engages with the corresponding positioning pin 522.

[0049] The top ends of a pair of support rods 65 are rotatably connected to the middle of a pair of clamping rods 64, and the bottom ends of the pair of support rods 65 are fixedly connected to the slider 611 via brackets 67; the piston rods of a pair of clamping cylinders 66 are rotatably connected to the higher end of a pair of clamping rods 64, and the bottom of the cylinders are fixedly connected to brackets 67.

[0050] During operation, the linear module moves together with the pre-pressing upper punch mechanism and the displacement guide rod along the ball guide seat. The extension and retraction of a pair of pressing cylinders causes a pair of pressing rods to rotate around the top of the corresponding support rods, thereby pressing or releasing the pre-pressing upper punch mechanism and improving the stability of the pre-pressing upper punch mechanism during the pre-pressing process.

[0051] Preferably, the locating pin 522 is made of polyurethane material, which has a certain degree of elasticity. Even if there is a slight positional deviation between the drive rod and the mating axis of the insertion hole of the connector, the locating pin can undergo moderate elastic deformation under the pressure of the slot, so that the drive rod can smoothly enter the insertion hole.

[0052] 4. Servo drive mechanism Servo drive mechanism 71, such as Figures 7-8 As shown, it includes: a pair of drive rods 71, a servo motor 72, a housing 73, and a worm gear 74, a worm wheel 75, a nut 76, a lead screw 77 and a drive plate 78 located in the housing.

[0053] The housing 73 is mounted on the fixed plate 12 of the forming upper punch mechanism, and the servo motor 72 is mounted on the housing. The worm 74 is driven and connected to the output shaft of the servo motor 72, and the worm wheel 75 is meshed and driven with the worm 74, and is provided with a central hole. The nut 76 is fixedly installed in the central hole of the worm wheel 75 and is provided with a central threaded hole. The lead screw 77 is threadedly connected to the central threaded hole of the nut 76 (the lead screw and nut are a standard lead screw and nut set). The drive plate 78 is fixedly connected to the lead screw 77, and a pair of drive rods 71 ​​are symmetrically installed at the bottom of the drive plate 78, and the drive rods 71 ​​extend downward through the fixed plate 12 of the forming upper punch mechanism 10.

[0054] During operation, the servo motor drives the worm gear, which in turn rotates the worm wheel and nut, causing the lead screw to move up and down, thus driving the rod to move up or down.

[0055] Preferably, the end of the drive rod 71 is frustum-shaped, forming a guide cone surface.

[0056] 5. Material handling mechanism Material handling mechanism 80, such as Figure 2 , Figure 9 As shown, it includes: a servo slide 81, a material channel 82 mounted on the frame, and a material pick-up lever 83; the material pick-up lever 83 is connected to the servo slide 81 and is provided with a material pick-up groove 831 that matches the shape of the pressed blank, so as to realize the automatic removal of the pressed blank after demolding.

[0057] The first powder feeding mechanism 41 and the second powder feeding mechanism 42 are respectively arranged on opposite sides of the forming die mechanism 20, and the displacement mechanism 60 (pre-pressing upper punch mechanism 50) and the material taking mechanism 80 are respectively arranged on the other opposite sides of the forming die mechanism 20. Each actuator does not interfere with the others.

[0058] Preferably, the frame is provided with dust collection hoppers 90 at the corresponding positions of the first powder feeding mechanism 41, the second powder feeding mechanism 42, the displacement mechanism 60 (pre-pressing upward punching mechanism 50) and the material picking mechanism 80. Each dust collection hopper is located below the moving path of the corresponding actuator and is used to collect excess dust that falls during the displacement process.

[0059] Example 2 The double-layer powder material servo pre-pressing forming method comprises the following steps: (1) driving the first powder feeding mechanism 41 to move forward on the powder feeding panel 40 to feed the first powder metallurgy material into the mold cavity 21 of the forming middle die mechanism, and after the powder feeding is completed, driving the first powder feeding mechanism 41 to move backward to reset; (2) driving the forming upper punch mechanism 10 to move downward to the first position, and the servo driving mechanism 70 moves downward at the same time; (3) the displacement mechanism 60 works to drive the pre-pressing upper punch mechanism 50 to move forward to the pre-pressing station; (4) the power mechanism works to drive the driving rod 71 to move downward, the driving rod enters the insertion hole 561 corresponding to the engaging head 56, the driving rod 71 continues to move downward and drives the pre-pressing upper punch 55 to move downward, the pre-pressing upper punch 55 enters the mold cavity 21, the first powder metallurgy material in the mold cavity 21 is pre-pressed by the pre-pressing upper punch 55 to form a first powder metallurgy material layer, and a pre-pressing surface is formed on the surface of the first powder metallurgy material layer; (5) the power mechanism drives the driving rod 71 to move upward to reset, the pre-pressing upper punch 55 moves upward to reset under the action of the spring, and the displacement mechanism 60 works to drive the pre-pressing upper punch mechanism to move backward to the avoiding station; (6) driving the second powder feeding mechanism 42 to move forward on the powder feeding panel 40 to feed the second powder metallurgy material into the mold cavity 21 of the forming middle die mechanism, and after the powder feeding is completed, driving the second powder feeding mechanism 42 to move backward to reset; (7) driving the forming upper punch mechanism 10 to continue to move downward to the second position, the forming upper punch 11 enters the mold cavity 21, and the first and second powder metallurgy materials in the mold cavity are integrally pressed by the forming upper punch 11 to obtain a double-layer structure powder metallurgy material compact; The servo sliding table 81 works to move the material taking and pushing rod 83 to the side of the mold cavity 21 and opposite to the first powder feeding mechanism 41; (8) driving the forming upper punch mechanism 10 to move upward to reset; under the cooperation of the forming middle die mechanism 20, the forming core rod mechanism 31 and the forming lower punch mechanism 30, the formed compact is pushed out of the mold cavity; (9) entering the production of the next batch of compacts, in the process of moving the first powder feeding mechanism 41 to the mold cavity 21 to feed powder, the first powder feeding mechanism 41 pushes the formed compact into the material taking groove 831 of the material taking and pushing rod 83; The servo sliding table 81 controls the material taking and pushing rod 83 to reset, and the material taking and pushing rod 83 feeds the compact into the material channel 82.

[0060] Preferably, as Figure 6 , Figure 7 , Figure 9As shown, two independent mold cavities 21 are provided in the forming die mechanism 20, and two pre-pressing upper punch heads 55 are provided in the pre-pressing upper punch mechanism, and two forming upper punch heads 11 are provided at the bottom of the forming upper punch mechanism 10, and two material taking grooves 831 are provided on the material taking lever 83, so as to form two pressings at one time.

[0061] Preferably, when the crank of the crank slider mechanism rotates from the top dead center (0° position) to the interval of 30°-60°, the forming upper punch mechanism driven thereby descends to the first position. When the crank of the crank slider mechanism rotates to the bottom dead center (180°), the forming upper punch mechanism driven thereby descends to the lowest end of the stroke, i.e. to the second position.

[0062] Embodiment 3 The application of the embodiment 1 or the embodiment 2 in the preparation of the valve seat ring can reduce the material cost of the valve seat ring.

[0063] The valve seat ring is a core component of the valve train of an automobile engine, which cooperates with the valve to seal the combustion chamber. The part needs to withstand the frequent impact of the valve under the working conditions of high temperature and high mechanical stress for a long time, and therefore the main working area (such as the sealing cone surface) in contact with the valve is required to have good wear resistance and heat resistance.

[0064] At present, most valve seat rings are made of a single high-performance powder metallurgy material, however, in the overall structure of the valve seat ring, there is a part of the secondary working area (such as the outer ring support area) which does not directly contact the valve, and the requirement for wear resistance and heat resistance of this area is relatively low. If a single high-performance powder metallurgy material is used to make the entire part, the material cost is high.

[0065] By using the scheme of the embodiment 1 or the embodiment 2, two different powder metallurgy materials are used to make the valve seat ring, which can appropriately reduce the material cost of the secondary working area.

[0066] As shown in Figure 6 The end of the pre-pressing upper punch head 55 is provided with a circular truncated cone structure, so that the pre-pressing surface of the first powder metallurgy material (low-cost material) forms a precise conical surface after pre-pressing. The finally press-formed valve seat ring is shown in Figure 11 The interlayer bonding surface between the main working area 101 (high-performance material) and the secondary working area 102 (low-cost material) is a conical surface (the cross section is a slanted line).

[0067] The conical interface can allow the main working area to have sufficient thickness, without affecting the performance of the valve seat ring, maximally increase the volume ratio of the secondary working area, and greatly reduce the material cost. In addition, the conical surface can also help to improve the bonding strength of the two materials.

Claims

1. A servo pre-compression forming device for double-layer powder materials, comprising a frame, a forming upper punch mechanism, a forming middle die mechanism, a forming lower punch mechanism, a forming mandrel mechanism, and a powder feeding mechanism mounted on the frame, characterized in that it further comprises... include: The pre-compression upper punch mechanism includes a pre-compression upper punch head; A displacement mechanism, connected to the pre-pressing upper punch mechanism, is used to drive the pre-pressing upper punch mechanism to move between the pre-pressing station and the clearance station above the mold cavity of the forming die mechanism; A servo drive mechanism is mounted on the forming upper punch mechanism and moves synchronously with it; The servo drive mechanism includes: a power mechanism and a drive rod driven by the power mechanism; The powder feeding mechanism includes a first powder feeding mechanism and a second powder feeding mechanism, which are respectively used to feed the first powder metallurgy material and the second powder metallurgy material into the mold cavity of the forming mold mechanism in sequence. Specifically, when the forming upper punch mechanism descends to the first position and the pre-pressing upper punch mechanism is located at the pre-pressing station, the driving power mechanism is activated to engage the driving rod with the pre-pressing upper punch mechanism and drive the pre-pressing upper punch head downward to complete the pre-pressing of the first powder metallurgy material; subsequently, the forming upper punch mechanism continues to descend to the second position to complete the pressing and forming of the double-layer powder metallurgy material.

2. The servo pre-compression forming device for double-layer powder materials according to claim 1, characterized in that, The pre-pressurized upward punching mechanism further includes: An upper pressure plate is used to engage with the drive rod, and the pre-pressed upper punch is fixedly installed at the bottom of the upper pressure plate; The lower pressure plate is arranged parallel to the lower pressure plate below it and is used to connect with the displacement mechanism. The lower pressure plate is provided with a clearance opening to facilitate the passage of the pre-pressed upper punch. Four preload guide rods are fixedly connected at their bottoms to the four corners of the lower pressure plate, and their tops pass through the upper pressure plate and are slidably connected to the upper pressure plate. Four springs are respectively fitted around the four preloaded guide rods and compressed between the upper and lower pressure plates.

3. The servo pre-compression forming device for double-layer powder materials according to claim 2, characterized in that, The top of the upper pressure plate is provided with a coupling head that mates with the drive rod, and the top of the coupling head is provided with an insertion hole that mates with the end of the drive rod.

4. The servo pre-compression forming device for double-layer powder materials according to claim 1, characterized in that, The displacement mechanism includes: A linear module, including a slider; A ball guide seat is fixedly installed on the base of the linear module and has a through ball guide hole; The displacement guide rod passes through the ball guide hole, and one end of it is connected to the preload upper punch mechanism; The pressing mechanism is connected to the slider and the pre-pressing upper punch mechanism respectively, so as to drive the pre-pressing upper punch mechanism to move along the ball guide seat and make the pre-pressing upper punch mechanism closely adhere to the powder feeding panel.

5. The servo pre-compression forming device for double-layer powder materials according to claim 4, characterized in that, The clamping mechanism includes: A pair of clamping rods are arranged in parallel and symmetrically, with their lower ends respectively connected to the pre-compression upward punching mechanism; A pair of support rods are arranged in parallel and symmetrically, with their top ends rotatably connected to a pair of clamping rods, and their bottom ends fixedly connected to the slider via brackets. A pair of clamping cylinders are arranged in parallel and symmetrically, with their piston rods rotatably connected to the higher end of a pair of clamping rods, and their cylinder bottoms fixedly connected to the brackets. By extending and retracting the pair of clamping cylinders, the pair of clamping rods rotate around the top of the corresponding support rods to clamp or release the pre-pressurized upward punching mechanism.

6. The servo pre-compression forming device for double-layer powder materials according to claim 1, characterized in that, The servo drive mechanism also includes: The housing is mounted on the fixing plate of the forming upper punch mechanism; A servo motor is mounted on the housing; The worm gear is driven and connected to the output shaft of the servo motor; A worm gear, which meshes and drives with the worm, and has a central hole; A nut is fixedly installed in the center hole of the worm gear and has a center threaded hole; The lead screw is threaded into the central threaded hole of the nut. A drive plate, fixedly connected to the lead screw, is used to mount the drive rod; the drive rod passes through the fixing plate of the forming upper punch mechanism; A servo motor drives a worm gear, which in turn rotates the worm wheel and nut, causing the lead screw to move up and down, thus enabling the drive rod to move upward or downward.

7. The servo pre-compression forming device for double-layer powder materials according to claim 1, characterized in that, It also includes a material handling mechanism, which includes: Servo slide; The feed chute is installed on the frame; The material picking lever is connected to the servo slide and has a material picking groove that matches the shape of the pressed blank.

8. The servo pre-compression forming device for double-layer powder materials according to claim 7, characterized in that, The first powder feeding mechanism and the second powder feeding mechanism are respectively arranged on opposite sides of the forming die mechanism, and the displacement mechanism and the material taking mechanism are respectively arranged on the other opposite sides of the forming die mechanism.

9. The servo pre-compression forming device for double-layer powder materials according to claim 1, characterized in that, The end of the pre-pressing upper punch has a frustum structure so that the pre-pressing surface of the first powder metallurgy material forms a conical surface.

10. A servo pre-compression forming method for double-layer powder materials, using the apparatus according to any one of claims 1-9, characterized in that, Includes the following steps: (1) Drive the first powder feeding mechanism to move forward on the powder feeding panel to feed the first powder metallurgy material into the mold cavity of the forming mold mechanism. After the powder feeding is completed, drive the first powder feeding mechanism to move backward to reset. (2) The driving forming upper punch mechanism moves down to the first position, and the servo drive mechanism moves down accordingly; (3) The displacement mechanism operates, driving the pre-pressing upward punching mechanism to move forward to the pre-pressing station; (4) The power mechanism works, causing the drive rod to descend and engage with the pre-pressing upper punch mechanism. The drive rod continues to descend and drives the pre-pressing upper punch to descend, pre-pressing the first powder metallurgy material in the mold cavity through the pre-pressing upper punch to form the first powder metallurgy material layer. (5) The power mechanism causes the drive rod to move upward and reset, and the pre-pressed upper punch moves upward and reset under the action of the spring; the displacement mechanism works to drive the pre-pressed upper punch mechanism to move backward to the avoidance position; (6) Drive the second powder feeding mechanism to move forward on the powder feeding panel to feed the second powder metallurgy material into the mold cavity of the forming mold mechanism. After the powder feeding is completed, drive the second powder feeding mechanism to move backward to reset. (7) Drive the forming upper punch mechanism to continue to descend to the second position, and press the first and second powder metallurgy materials in the mold cavity through the forming upper punch to obtain a double-layer powder metallurgy material blank; (8) Drive the upper punch mechanism to move upward and reset; with the cooperation of the middle die mechanism, the forming mandrel mechanism and the lower punch mechanism, the formed blank is ejected out of the die cavity.

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