Pressure transmitter pressure seat and integrated forming die thereof

Abstract

The invention relates to the technical field of pressure seat manufacturing, in particular to a pressure transmitter pressure seat and an integrated forming die thereof, the pressure seat is provided with a pressure butt joint part connected with an annular groove, the pressure seat is provided with a first axial matching outer cover and a second axial matching outer cover, the first axial matching outer cover is provided with a press-in positioning flat position, and the second axial matching outer cover is provided with a press-in positioning flat position. A stress groove is formed between the first axial matching outer cover and the second axial matching outer cover, and a pressure guiding hole is formed in the pressure seat; the preparation mold is provided with an inner mold, and a cooling cavity is formed in the area between the inner mold and the mold body. The pressure seat is integrally formed by metal powder injection molding, a cooling runner is arranged in the mold, cooling can be performed according to the injection height, the shrinkage rate of parts during production can be more accurately controlled, and the dimensional deviation caused by overlarge temperature change is reduced, so that the high precision of the parts is ensured, the axial surface mounting of the strain gauge is realized, and the production efficiency is improved. And optimization design such as miniaturization of the internal size of the pressure transmitter is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of manufacturing workpieces with metal powder, in particular to a pressure transmitter pressure seat and an integral forming die thereof. Background Art

[0002] A pressure sensor is a device or apparatus that can sense pressure signals and convert them into usable output electrical signals according to certain rules. Brake pressure transmitters can be used in body stability systems (ESC / ESP) or OneBox wire control brake systems in assisted driving and autonomous driving vehicles to monitor the hydraulic pressure signals in the pipelines of the brake system in real time. The control unit calculates the wheel braking force and the longitudinal force acting on the vehicle based on this pressure signal. Based on the pressure signal provided by the brake pressure transmitter, the system can adjust the braking force more intelligently, thereby improving the driving stability and safety of the vehicle. In addition, the pressure signal provided by the brake pressure transmitter can also assist the brake energy recovery system (EBS) of new energy vehicles in managing energy recovery and distribution, thereby improving the braking efficiency and energy saving of the vehicle.

[0003] Existing pressure brakes are often manufactured by machining, and then the side plugs are installed by welding. The processing design of this type of pressure seat is relatively complex and costly. In addition, since the pressure seat needs to withstand a hydraulic pressure of at least 25MPa, the plug is small, the welding process requirements are also high, and there is a risk of leakage. At the same time, limited by the installation size requirements of the braking system, the volume size of the pressure seat must be very small. For example, some products require the size of the pressure-inducing hole to be no larger than φ3.3mm, and the diameter of the electronic cavity to be no larger than φ7.75mm. Since the size of the electronic cavity that can hold the circuit board is very small, the conventional radial placement of the circuit board becomes difficult, and the circuit board needs to be placed horizontally to make the structure simple and reliable. Based on the horizontal placement of the circuit board, the patch position of the strain gauge needs to be changed to an axial form. Conventional products are all placed radially. Summary of the invention

[0004] The object of the present invention is to provide a pressure seat of a pressure transmitter and an integral molding die thereof, so as to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions: A pressure seat of a pressure transmitter, wherein one end of the pressure seat is provided with a pressure docking portion connected to a ring groove, the pressure docking portion is provided with a first axial matching outer cover, the pressure docking portion is opened to the circular cross-section where the first axial matching outer cover is located to form a pressure transmission channel, the first axial matching outer cover is provided with a press-in positioning flat position horizontally downward, the pressure seat is provided with a second axial matching outer cover, the radius of the second axial matching outer cover is smaller than the first axial matching outer cover; a stress groove is provided between the first axial matching outer cover and the second axial matching outer cover, the stress groove is used to change the stress distribution and reduce the influence of external stress on the film surface; a pressure-inducing hole is provided at the bottom of the pressure transmission channel; a patch platform is provided at the other end of the pressure seat for axial patching of strain gauges and placement of circuit boards; the pressure seat is integrally formed by metal powder injection molding.

[0006] Preferably, the pressure-inducing hole is elliptical, is opened at the bottom of the pressure transmission channel, and extends to the strain gauge mounting platform.

[0007] Preferably, the pressure-inducing hole is any one of circular, open or square, is opened at the bottom of the pressure transmission channel, and extends to the strain gauge mounting platform.

[0008] Preferably, an axial step is provided between the second axial matching outer cover and the patch platform, and a positioning flat position is provided horizontally upward on the axial step for positioning the pressure seat bracket.

[0009] Preferably, the metal powder injection molding process comprises the following steps: Step 1: Heat and mix the metal powder and the binder in proportion to form a uniform granular mixture; Step 2: Heat the granular mixture to 180-200°C, feed it into an injection molding machine, and inject it into a mold under high pressure to obtain a pressure seat green body; Step 3: The injection molded parts are subjected to a thermal degreasing treatment at 85-125°C to remove the binder in the green body of the pressure seat; Step 4: Place the degreased pressure seat into a sintering furnace for high-temperature sintering at 200-1275°C; Step 5: heat-treating the sintered pressure seat at 600-800°C; Step 6: Place the heat-treated pressure seat into a magnetic grinding machine for magnetic grinding; Step 7: Place the ground pressure seat into a drying box for drying.

[0010] Preferably, the metal powder used in step 1 is SUS630, the particle size D50 of the metal powder is in the range of 8.00-9.00um, the tap density of the metal powder is ≥4.60g / cm3, the weight ratio of the metal powder to the binder is 9:1, and the volume ratio of the metal powder to the binder is 1:1; the binder includes POM, PP, PA, PE and EVA.

[0011] Preferably, the weight ratio of the POM to the total weight of the binder is 9:10.

[0012] In another aspect of the present invention, an integrated molding die is provided for preparing the pressure seat of the pressure transmitter, and the mold comprises: A mold body, wherein the mold body is provided with an inner mold, a cooling cavity is formed in the area between the inner mold and the mold body, a push rod and a driving push rod for driving the push rod to move are provided inside the mold body, the driving push rod is used to push the push rod into the inner mold so that the push rod and the inner mold together form a cavity of the pressure seat, the mold body comprises an upper mold and a lower mold, the upper mold and the lower mold are both provided with an inner mold, the upper mold is provided with an injection hole, and the injection hole and the inner mold provided on the upper mold are communicated with each other; A closing assembly, the closing assembly comprising a closing push rod, the closing push rod being connected to the upper mold, and the closing push rod being used to drive the upper mold and the lower mold to close; A cooling assembly, the cooling assembly includes a liquid storage tank, a cooling pipe, a liquid return pipe, a docking mechanism 1, a docking mechanism 2, a connecting mechanism and a circulation mechanism, the liquid storage tank is arranged on the lower mold and is used to store coolant, the cooling pipe and the liquid return pipe are both arranged in the cooling cavity, the docking mechanism 1 is used to dock the cooling pipe arranged on the upper mold and the cooling pipe arranged on the lower mold with each other when the upper mold and the lower mold are closed to each other, the docking mechanism 2 is used to dock the liquid return pipe arranged on the upper mold and the liquid return pipe arranged on the lower mold with each other when the upper mold and the lower mold are closed to each other, the connecting mechanism is used to connect the cooling pipes and the liquid return pipes at different heights with each other according to the injection height of the inner mold, and the circulation mechanism is used to drive the coolant to circulate between the cooling pipe, the liquid return pipe and the liquid storage tank.

[0013] Preferably, the communication mechanism comprises a three-way valve, and three interfaces of the three-way valve are respectively connected to two adjacent cooling pipes and the liquid return pipe.

[0014] Preferably, the docking mechanism includes a magnetic block, a movable push rod and a sealing ring. A magnetic block is provided at the docking interface of the cooling tube arranged on the upper mold and the cooling tube arranged on the lower mold. The movable push rod is connected to one of the magnetic blocks and is used to drive the sealing ring to seal the docking interface of the cooling tube when the two magnetic blocks are docked with each other.

[0015] Preferably, the docking mechanism 2 includes a magnetic block 2, a movable push rod 2 and a sealing ring 2. A magnetic block 2 is provided at the docking interface of the return liquid pipe arranged on the upper mold and the return liquid pipe arranged on the lower mold. The movable push rod 2 is connected to one of the magnetic blocks 2 and is used to drive the sealing ring 2 to seal the docking interface of the return liquid pipe when the two magnetic blocks 2 are docked with each other.

[0016] Preferably, the circulation mechanism comprises a circulation pump, which is arranged in the liquid storage tank, the output end of the circulation pump and the cooling pipe are connected to each other, and the liquid return pipe arranged in the lower mold is connected to the liquid storage tank.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention provides a pressure seat of a pressure transmitter, which is provided with a stress groove, a diameter positioning and a pressure-inducing hole. After repeated tests and calculations, the pressure-inducing hole is set to an ellipse, and the linear deformation of the strain gauge surface is optimal, thereby realizing the horizontal placement of the circuit board and the axial patch of the strain gauge. Combined with the MIM process, the complex structure and miniaturized design of the pressure seat are realized, which greatly reduces the production cost compared with the mechanical processing process, and at the same time achieves higher product structure accuracy.

[0018] 2. The present invention provides an integrated molding mold for preparing the pressure seat. The cooling liquid paths in the upper mold and the lower mold are connected when the upper mold and the lower mold are docked with each other through the docking mechanism 1 and the docking mechanism 2 arranged in the mold, and the pressure seat inside the mold is cooled according to the injection height during injection, which can ensure the rapid solidification of the parts in the mold, thereby shortening the production cycle and improving production efficiency. At the same time, cooling according to the injection height can more accurately control the shrinkage rate of the parts during production and reduce the dimensional deviation caused by excessive temperature changes, thereby ensuring the high precision of the parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the three-dimensional structure of the pressure seat of the present invention; Figure 2 It is a schematic cross-sectional view of the pressure seat of the present invention; Figure 3 It is a schematic diagram of the design dimensions of the pressure-introducing hole in the pressure seat of the present invention; Figure 4A research comparison table of the strain of the pressure seat surface strain gauge of different pressure-inducing holes of the present invention; Figure 5 It is a schematic diagram of the mold structure of the present invention; Figure 6 It is a schematic diagram of the connection structure of the ejector rod, the driving push rod and the lower mold of the present invention; Figure 7 This is a schematic diagram of the cooling chamber and cooling pipe position structure of the present invention; Figure 8 It is a schematic diagram of the connection structure of the cooling pipe and the liquid return pipe of the present invention.

[0020] In the figure: 1 inner mold, 2 cooling cavity, 3 ejector rod, 4 driving push rod, 5 upper mold, 6 lower mold, 7 closing push rod, 8 liquid storage tank, 9 cooling pipe, 10 liquid return pipe, 11 three-way valve, 12 magnetic block 1, 13 moving push rod 1, 14 sealing ring 1, 15 magnetic block 2, 16 moving push rod 2, 17 sealing ring 2, 18 circulating pump, 100 pressure seat, 101 connecting ring groove, 102 pressure docking part, 103 first axial matching outer cover, 104 pressure transmission channel, 105 positioning flat position, 106 second axial matching outer cover, 107 stress groove, 108 pressure guide hole, 109 patch table, 501 injection hole. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0022] See also Figure 1-8 , the present invention provides a technical solution: A pressure seat of a pressure transmitter, wherein a pressure docking portion connected to a ring groove 102 is provided at one end of the pressure seat 100, and a first axial matching outer cover 103 is provided at the pressure docking portion, and a pressure transmission channel 104 is formed at the circular cross section where the first axial matching outer cover 103 is located through an opening in the pressure docking portion, and a press-in positioning flat position 105 is provided horizontally downward on the first axial matching outer cover 103, and the pressure seat 100 is provided with a second axial matching outer cover 106, and the radius of the second axial matching outer cover 106 is smaller than that of the first axial matching outer cover 103; a stress groove 107 is provided between the first axial matching outer cover 103 and the second axial matching outer cover 106, and the stress groove 107 is used to change the stress distribution and reduce the influence of external stress on the film surface; a pressure-inducing hole 108 is provided at the bottom of the pressure transmission channel 104; a patch platform 109 is provided at the other end of the pressure seat 100 for axial patching of strain gauges and placing circuit boards; the pressure seat 100 is integrally formed by metal powder injection molding.

[0023] In a preferred embodiment of the present invention, the pressure-inducing hole 108 is elliptical, is opened at the bottom of the pressure transmission channel 104 , and extends to the strain gauge mounting platform 109 .

[0024] In other embodiments of the present invention, the pressure-inducing hole 108 is in any of circular, open or square shapes, is opened at the bottom of the pressure transmission channel 104 , and extends to the strain gauge mounting platform 109 .

[0025] The metal powder injection molding process includes the following steps: Step 1: Heat and mix the metal powder and binder in proportion. The heating temperature is controlled according to the material properties. The temperature is controlled and observed to form a uniform granular mixture. The purpose of adding the binder is to improve the fluidity and molding performance of the mixture. When mixing, it is necessary to ensure that each metal powder particle is coated to form a uniform mixture. Step 2: feeding the granular mixture into an injection molding machine for heating, with the heating parameters controlled at a nozzle temperature of 200° C., a barrel temperature of 195° C., a front temperature of 190° C., a middle temperature of 185° C., a rear temperature of 180° C., an injection pressure of 190 MPa, and an injection speed of 105 mm / s, and injecting the mixture into the mold under high pressure to form the shape of the basic pressure seat 100, thereby obtaining a green body of the pressure seat 100; Step 3: The injection molded parts are subjected to thermal degreasing treatment, which includes: Pre-flushing, time 90min, furnace chamber temperature 85℃, furnace door temperature 105℃, gasification box temperature 175℃, pipeline temperature 180℃, fan speed 40%, nitrogen flow 80L / min; Degreasing 1, time 60min, furnace chamber temperature 85℃, furnace door temperature 110℃, gasification box temperature 175℃, pipeline temperature 180℃, fan speed 35%, nitrogen flow 60L / min; Degreasing II, time 460min, furnace chamber temperature 88℃, furnace door temperature 110℃, gasification box temperature 175℃, pipeline temperature 180℃, fan speed 35%, nitrogen flow 60L / min; Degreasing 3, time 320min, furnace chamber temperature 110℃, furnace door temperature 132℃, gasification box temperature 175℃, pipeline temperature 180℃, fan speed 35%, nitrogen flow 60L / min; Post-rinsing 1, time 60min, furnace chamber temperature 125℃, furnace door temperature 140℃, gasification box temperature 175℃, pipeline temperature 180℃, fan speed 50%, nitrogen flow 90L / min; Post-rinsing 2, time 30min, furnace door temperature 140℃, fan speed 55%, nitrogen flow 90L / min; This removes the binder in the green mixture of the pressure seat 100; Step 4: Place the degreased pressure seat 100 into a sintering furnace for high-temperature sintering: Sintering 1: temperature 200℃, time 60min, process negative pressure degreasing, nitrogen flow rate 35L / min; Sintering II: temperature 200°C, time 40 min, process negative pressure degreasing, nitrogen flow 35 L / min; Sintering 3: temperature 450℃, time 80min, process negative pressure degreasing, nitrogen flow rate 35L / min; Sintering 4: temperature 450℃, time 60min, process negative pressure degreasing, nitrogen flow rate 35L / min; Sintering 5: temperature 650℃, time 80min, process negative pressure degreasing, nitrogen flow rate 35L / min; Sintering six: temperature 650℃, time 60min, process negative pressure degreasing, nitrogen flow rate 35L / min; Sintering seven: temperature 800℃, time 80min, process negative pressure degreasing, nitrogen flow rate 35L / min; Sintering eight: temperature 800°C, time 60 min, process negative pressure degreasing, nitrogen flow rate 35 L / min; Sintering nine: temperature 1050℃, time 100min, process vacuum sintering; Sintering ten: temperature 1050℃, time 70min, process vacuum sintering; Sintering 11: temperature 1240°C, time 70 min, process partial pressure sintering, pressure 40 MPa, argon flow rate 30 L / min; Sintering 12: temperature 1275℃, time 30min, process partial pressure sintering, pressure 40Mpa, argon flow rate 30L / min; Sintering 13: temperature 1275°C, time 180 min, process partial pressure sintering, pressure 40 MPa, argon flow rate 30 L / min; Sintering 14: temperature 900°C, time 60min, process partial pressure sintering, pressure 40Mpa, argon flow rate 30L / min; Sintering 15: temperature 60°C, time 30min, process forced cooling, pressure 86Mpa; This promotes the bonding between metal particles and improves the density and strength of parts.

[0026] Step 5: heat-treating the sintered pressure seat 100. In this embodiment, the heat-treating method is tempering, which eliminates the residual stress generated during the sintering process and improves the hardness and wear resistance of the pressure seat 100. Step 6: The heat-treated pressure seat 100 is placed in a magnetic grinding machine for magnetic grinding. During the magnetic grinding process, the magnetic abrasive rotates at a high speed under the action of the magnetic field and rubs against the inner and outer surfaces of the pressure seat 100, thereby removing tiny flaws and burrs on the surface; Step 7: Place the ground pressure seat 100 into a drying box for drying. The drying process is used to remove moisture and grinding liquid residue on the inner and outer surfaces of the pressure seat 100.

[0027] Limited by the installation size requirements of the brake system, the pressure seat volume size must be very small (see the attached manual Figure 3 As shown, the size of the pressure-inducing hole 108 is not greater than φ3.3mm). In order to meet the electrical performance of the braking system while meeting the installation of the horizontal circuit board, based on the horizontal placement of the circuit board, the patch position of the strain gauge needs to be axial. In order to achieve axial patching, the pressure-inducing hole 108 needs to be designed. The data from the research on the strain of the strain gauge on the surface of the pressure seat are combined. Compared with the open hole, square hole, and circular hole, the elliptical hole-type pressure-inducing hole 108 has a large strain force variation range and better linearity. In this embodiment, the linear deformation of the strain gauge surface is optimal, so the pressure-inducing hole 108 is an elliptical hole, which is the best solution.

[0028] As attached Figure 1 and attached Figure 2 As shown, during operation, pressure enters through the pressure transmission channel of the pressure receiving part, acts on the patch platform 109 where the strain gauge is located, and then acts on the strain gauge where the strain gauge is located. The strain gauge is deformed, resulting in a change in the resistance of the strain gauge. The strain gauge detects the change in the resistance of the strain gauge and converts it into an electrical signal. Among them, the shape and size of the pressure-inducing hole 108 have an important influence on the distribution of strain. Compared with the open hole, square hole and circular hole-type pressure-inducing hole 108, the elliptical hole-type pressure-inducing hole 108 can further optimize the distribution of strain, so that the pressure is more evenly distributed on the strain gauge, reducing local stress concentration, so that the strain gauge can more accurately detect pressure changes, thereby improving the accuracy and reliability of measurement.

[0029] The stress field expression around the elliptical orifice is as follows: in, σxx , σyy ,and σxy are the normal stress and shear stress components, represents the real part, ζ is a complex variable, ρ is a point on the orifice boundary, ω ( ζ ) is the conformal transformation function.

[0030] The stress value gradually decreases with the increase of the distance between the field point and the coordinate origin. When the distance between the field point and the coordinate origin is much greater than the orifice limit, each stress component tends to a constant value.

[0031] In this embodiment, the metal powder used in step 1 is SUS630, the particle size D50 of the metal powder is in the range of 8.00-9.00um, the tap density of the metal powder is ≥4.60g / cm3, the weight ratio of the metal powder to the binder is 9:1, the volume ratio of the metal powder to the binder is 1:1, and the binder includes POM, PP, PA, PE and EVA, wherein the weight ratio of the total weight of POM and the binder is 9:10.

[0032] As the instruction manual Figure 5 As shown, the mold includes: The mold body is provided with an inner mold 1, and the inner mold 1 is used to cooperate with the mold body to form a cooling cavity 2. The cooling cavity 2 is formed in the area between the inner mold 1 and the mold body. A push rod 3 and a driving push rod 4 for driving the push rod 3 to move are provided inside the mold body. The driving push rod 4 is a hydraulic push rod. The driving push rod 4 is used to push the push rod 3 into the inner mold 1 so that the push rod 3 and the inner mold 1 together form a cavity of the pressure seat 100. The mold body includes an upper mold 5 and a lower mold 6. The upper mold 5 and the lower mold 6 are both provided with the inner mold 1. The upper mold 5 is provided with an injection hole 501, and the injection hole 501 is connected with the inner mold 1 provided on the upper mold 5. The closing assembly includes a closing push rod 7, which is also a hydraulic push rod. The closing push rod 7 is connected to the upper mold 5 and is used to drive the upper mold 5 and the lower mold 6 to close. A cooling assembly, the cooling assembly includes a liquid storage tank 8, a cooling pipe 9, a liquid return pipe 10, a docking mechanism 1, a docking mechanism 2, a connecting mechanism and a circulation mechanism. The liquid storage tank 8 is arranged on the lower mold 6 and is used to store coolant. In this embodiment, the coolant is an ethylene glycol type coolant, which is suitable for the use scenario of this application. The cooling pipe 9 and the liquid return pipe 10 are both arranged in the cooling cavity 2. The docking mechanism 1 is used to dock the cooling pipe 9 arranged on the upper mold 5 and the cooling pipe 9 arranged on the lower mold 6 with each other when the upper mold 5 and the lower mold 6 are closed to each other. The docking mechanism 2 is used to dock the liquid return pipe 10 arranged on the upper mold 5 and the liquid return pipe 10 arranged on the lower mold 6 with each other when the upper mold 5 and the lower mold 6 are closed to each other. The connecting mechanism is used to connect the cooling pipes 9 and the liquid return pipes 10 of different heights with each other according to the injection height of the inner mold 1. The circulation mechanism is used to drive the coolant to circulate between the cooling pipe 9, the liquid return pipe 10 and the liquid storage tank 8.

[0033] The connecting mechanism includes a three-way valve 11, which is a solenoid valve. Each interface of the three-way valve 11 can be independently controlled to open and close. The three interfaces of the three-way valve 11 are respectively connected to two adjacent cooling pipes 9 and the return liquid pipe 10.

[0034] The docking mechanism 1 includes a magnetic block 12, a movable push rod 13 and a sealing ring 14. The cooling tube 9 arranged on the upper mold 5 and the cooling tube 9 arranged on the lower mold 6 are both provided with a magnetic block 12 at the docking interface. The cooling tube 9 arranged on the upper mold 5 and the cooling tube 9 arranged on the lower mold 6 can be adsorbed on each other. The movable push rod 13 is connected to one of the magnetic blocks 12 and is used to drive the sealing ring 14 to seal the docking interface of the cooling tube 9 when the two magnetic blocks 12 are docked with each other. In this embodiment, the movable push rod 13 and the movable push rod 2 16 are both pneumatic push rods, which are suitable for the working scenario of this application.

[0035] The docking mechanism 2 includes a magnetic block 2 15, a movable push rod 2 16 and a sealing ring 2 17. The magnetic block 2 15 is provided at the docking interface of the return liquid pipe 10 arranged on the upper mold 5 and the return liquid pipe 10 arranged on the lower mold 6. The movable push rod 2 16 is connected to one of the magnetic blocks 2 15 and is used to drive the sealing ring 2 17 to seal the docking interface of the return liquid pipe 10 when the two magnetic blocks 2 15 are docked with each other.

[0036] The circulation mechanism includes a circulation pump 18, which is arranged in the liquid storage tank 8. The output end of the circulation pump 18 and the cooling pipe 9 are connected to each other. The return pipe 10 arranged in the lower mold 6 is connected to the liquid storage tank 8, so the coolant in the return pipe 10 will eventually flow back to the liquid storage tank 8.

[0037] Working principle: when in use, the closing push rod 7 will drive the upper mold 5 and the lower mold 6 to close to each other. When closing, the cooling tube 9 arranged on the upper mold 5 and the magnetic block 12 arranged on the cooling tube 9 arranged on the lower mold 6 can be adsorbed to each other. After the closing is completed, the moving push rod 13 will drive the sealing ring 14 to move and then seal the position where the two magnetic blocks 12 are connected; when closing, the return liquid pipe 10 arranged on the upper mold 5 and the magnetic block 2 15 arranged on the return liquid pipe 10 arranged on the lower mold 6 will also be adsorbed to each other, and the moving push rod 2 16 will drive the sealing ring 2 17 to move and then seal the position where the two magnetic blocks 2 15 are connected; when in use, according to the height of the mixture (including metal powder and binder) injected into the cavity, the three-way valves 11 at different heights will be opened to quickly cool it, so that the mixture (including metal powder and binder) in the cavity can be quickly formed.

[0038] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A pressure seat of a pressure transmitter, wherein one end of the pressure seat is provided with a pressure docking portion for connecting a ring groove, characterized in that: The pressure docking part is provided with a first axial matching outer cover, and a pressure transmission channel is formed at the circular cross-section where the pressure docking part opens to the first axial matching outer cover, and a press-in positioning flat position is provided horizontally on the lower side of the first axial matching outer cover, and the pressure seat is provided with a second axial matching outer cover, and the radius of the second axial matching outer cover is smaller than that of the first axial matching outer cover; a stress groove is provided between the first axial matching outer cover and the second axial matching outer cover, and the stress groove is used to change the stress distribution and reduce the influence of external stress on the film surface; a pressure-inducing hole is provided at the bottom of the pressure transmission channel; a patch platform is provided at the other end of the pressure seat for axial patching of strain gauges and placing circuit boards; the pressure seat is integrally formed by metal powder injection molding.

2. A pressure transmitter pressure seat according to claim 1, characterized in that: The pressure-inducing hole is elliptical, is opened at the bottom of the pressure transmission channel, and extends to the strain gauge mounting platform.

3. A pressure transmitter pressure seat according to claim 1, characterized in that: The pressure-inducing hole is any one of circular, open or square, is opened at the bottom of the pressure transmission channel, and extends to the strain gauge mounting platform.

4. A pressure transmitter pressure seat according to claim 1, characterized in that: An axial step is arranged between the second axial matching outer cover and the patch platform, and a positioning flat position is arranged horizontally upward on the axial step for positioning the pressure seat bracket.

5. A pressure transmitter pressure seat according to claim 1, characterized in that: The metal powder injection molding process comprises the following steps: Step 1: Heat and mix the metal powder and the binder in proportion to form a uniform granular mixture; Step 2: Heat the granular mixture to 180-200°C, feed it into an injection molding machine, and inject it into a mold under high pressure to obtain a pressure seat green body; Step 3: The injection molded parts are subjected to a thermal degreasing treatment at 85-125°C to remove the binder in the green body of the pressure seat; Step 4: Place the degreased pressure seat into a sintering furnace for high-temperature sintering at 200-1275°C; Step 5: heat-treating the sintered pressure seat at 600-800°C; Step 6: Place the heat-treated pressure seat into a magnetic grinding machine for magnetic grinding; Step 7: Place the ground pressure seat into a drying box for drying.

6. A pressure transmitter pressure seat according to claim 5, characterized in that: The metal powder used in step 1 is SUS630, the particle size D50 of the metal powder is in the range of 8.00-9.00um, the tap density of the metal powder is ≥4.60g / cm3, the weight ratio of the metal powder to the binder is 9:1, the volume ratio of the metal powder to the binder is 1:1, and the binder includes POM, PP, PA, PE and EVA.

7. A pressure transmitter pressure seat according to claim 6, characterized in that: The weight ratio of the POM to the total weight of the binder is 9:

10.

8. An integrated molding die for preparing a pressure seat of a pressure transmitter according to any one of claims 1 to 7, characterized in that: The one-piece molding die comprises: A mold body, wherein the mold body is provided with an inner mold, a cooling cavity is formed in the area between the inner mold and the mold body, a push rod and a driving push rod for driving the push rod to move are provided inside the mold body, the driving push rod is used to push the push rod into the inner mold so that the push rod and the inner mold together form a cavity of the pressure seat, the mold body comprises an upper mold and a lower mold, the upper mold and the lower mold are both provided with an inner mold, the upper mold is provided with an injection hole, and the injection hole and the inner mold provided on the upper mold are communicated with each other; A closing assembly, the closing assembly comprising a closing push rod, the closing push rod being connected to the upper mold, and the closing push rod being used to drive the upper mold and the lower mold to close; A cooling assembly, the cooling assembly includes a liquid storage tank, a cooling pipe, a liquid return pipe, a docking mechanism 1, a docking mechanism 2, a connecting mechanism and a circulation mechanism, the liquid storage tank is arranged on the lower mold and is used to store coolant, the cooling pipe and the liquid return pipe are both arranged in the cooling cavity, the docking mechanism 1 is used to dock the cooling pipe arranged on the upper mold and the cooling pipe arranged on the lower mold with each other when the upper mold and the lower mold are closed to each other, the docking mechanism 2 is used to dock the liquid return pipe arranged on the upper mold and the liquid return pipe arranged on the lower mold with each other when the upper mold and the lower mold are closed to each other, the connecting mechanism is used to connect the cooling pipes and the liquid return pipes at different heights with each other according to the injection height of the inner mold, and the circulation mechanism is used to drive the coolant to circulate between the cooling pipe, the liquid return pipe and the liquid storage tank.

9. The one-piece molding die according to claim 8, characterized in that: The connecting mechanism includes a three-way valve, and the three interfaces of the three-way valve are respectively connected to the two adjacent cooling pipes and the return liquid pipe; the docking mechanism includes a magnetic block, a movable push rod and a sealing ring. The docking interfaces of the cooling pipe arranged on the upper mold and the cooling pipe arranged on the lower mold are both provided with a magnetic block. The movable push rod is connected to one of the magnetic blocks and is used to drive the sealing ring to seal the docking interface of a pair of cooling pipes when the two magnetic blocks are docked with each other.

10. The one-piece molding die according to claim 8, characterized in that: The second docking mechanism includes a second magnetic block, a second movable push rod and a second sealing ring. The second magnetic block is provided at the docking interface of the return liquid pipe arranged on the upper mold and the return liquid pipe arranged on the lower mold. The second movable push rod is connected to one of the second magnetic blocks and is used to drive the second sealing ring to seal the docking interface of the return liquid pipe when the two second magnetic blocks are docked with each other. The circulation mechanism includes a circulation pump, which is arranged in the liquid storage tank, and the output end of the circulation pump and the cooling pipe are connected to each other. The return liquid pipe arranged in the lower mold is connected to the liquid storage tank.

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