Assembly process and assembly platform of pressure sensor and automatic assembly method

Abstract

The invention discloses an assembly process and assembly platform for a pressure sensor and an automatic assembly method, and the method comprises the steps: a, freezing an anti-freezing plug made of an elastic material in a low-temperature environment until the anti-freezing plug is reduced to be smaller than the aperture size of a drainage hole of the pressure sensor, the property is changed from elasticity to brittleness, and a frost layer is condensed on the surface; b, the opening of the drainage hole is upward; c, the anti-freezing plug is placed into the drainage hole to be sunk into the drainage hole; d, the anti-freezing plug further goes deep through the pressing rod; e, detecting whether the depth of the anti-freezing plug in the drainage hole reaches the standard or not, and if not, repeating the step d and the step e until the depth reaches the standard; and f, after the anti-freezing plug is unfrozen to restore the original size and elasticity, the anti-freezing plug and the inner wall of the drainage hole are elastically extruded and fixed. After the anti-freezing plug is frozen, the size is reduced, the property becomes brittle, and a frost layer for reducing friction force is formed on the surface; the difficulty of installing the anti-freezing plug into the deep position of the drainage hole is reduced, and meanwhile the surface of the anti-freezing plug does not need to be coated with a lubricant.

Description

Technical Field

[0001] The present invention relates to the field of exhaust gas treatment for fuel vehicles, and in particular to an assembly process, an assembly platform and an automated assembly method for a pressure sensor for exhaust gas of fuel vehicles. Background Art

[0002] The existing urea pressure sensor is an important sensor installed in the urea pump of a fuel vehicle to monitor vehicle exhaust. The position where the urea pressure sensor contacts the urea pump is equipped with an antifreeze plug, which prevents urea from crystallizing in the sensor cavity and affecting the pressure sensor's sensing of urea pressure.

[0003] At present, the assembly of antifreeze plugs is completed by the urea pressure sensor supplier. The installation process is to manually pre-install the antifreeze plug in the sensor hole at room temperature, and then press it to the bottom of the hole with a press-in tool. This assembly method has the following problems: 1. Manual compression efficiency is low and the compression depth is inconsistent; 2. The antifreeze plug rebounds after installation, causing the final product to be not installed properly, or even falling off during transportation.

[0004] The prior art discloses a method for assembling a sealing ring, which discloses a scheme in which a lubricant is coated on the surface of the sealing ring, and then the sealing ring is displaced and brittlely assembled after being frozen. However, the lubricant in the above scheme cannot be used on the antifreeze plug because the lubricant will affect the detection of the pressure sensor. Therefore, developing a process for quickly assembling the antifreeze plug into the drainage hole of the pressure sensor by freezing is a technical problem that needs to be solved at present. Summary of the invention

[0005] In view of the above problems, the present invention provides an assembly process of a pressure sensor, which can freeze the antifreeze plug and assemble it into the drainage hole of the pressure sensor without lubricant. The specific scheme is as follows: The assembly process of the pressure sensor includes the following steps: Step a, placing the antifreeze plug made of elastic material in a low temperature environment for freezing, until the antifreeze plug shrinks to a size smaller than the aperture of the drainage hole of the pressure sensor, the property of the antifreeze plug changes from elastic to brittle, and a frost layer with a thickness of 3 to 5 mm condenses on the surface; Step b, fixing the pressure sensor with its drainage hole opening facing upward; Step c, taking out the frozen antifreeze plug and putting it into the drainage hole, reducing the friction between the antifreeze plug and the drainage hole through the frost layer on the surface of the antifreeze plug, so that the antifreeze plug can be quickly lowered and prevent the antifreeze plug from being stuck in the drainage hole; Step d, inserting the pressure rod into the drainage hole to further penetrate the antifreeze plug; Step e, detecting whether the depth of the antifreeze plug in the drainage hole meets the standard, if not, repeating steps d and e until it meets the standard; Step f, waiting for the antifreeze plug to thaw and restore its original size and elasticity, so that the antifreeze plug is elastically squeezed and fixed to the inner wall of the drainage hole.

[0006] Furthermore, in the step f, the antifreeze plug expands and returns to its original size after thawing, and the size of the antifreeze plug is larger than the aperture of the drainage hole.

[0007] Furthermore, in step a, the glass transition temperature of the antifreeze plug is Tg, the brittle temperature of the antifreeze plug is Tb, and the freezing temperature t of the antifreeze plug is Tg≤t<Tb.

[0008] Furthermore, the t is -40°C.

[0009] Furthermore, in step a, the freezing time of the antifreeze plug is greater than 10 minutes.

[0010] Furthermore, an assembly platform for an assembly process of a pressure sensor includes a horizontally arranged material turntable, and a pressing device, a depth detection device, a first mechanical claw, and a second mechanical claw are evenly distributed in the circumference of the material turntable; The pressing device includes a pressing rod for pressing the antifreeze plug deep into the drainage hole, a driving unit for driving the pressing rod to vertically move, and a tool for fixing the pressure sensor; The assembly platform is located outside the first mechanical claw and is provided with a feeding tray for placing a pressure sensor; The assembly platform is located outside the second mechanical claw and is provided with a freezer, and a conveyor belt is connected between the freezer and the assembly platform; The assembly platform is located outside the depth detection device and is provided with a discharging tray for receiving the assembled pressure sensor.

[0011] Furthermore, the depth detection device is a CCD detector.

[0012] Furthermore, the depth detection device and the first mechanical claw are symmetrically arranged on the right side of the material turntable, and a material conveying rack is provided on the right side of the assembly platform, and the feeding tray and the discharging tray are arranged on the material conveying rack respectively; The pressing device and the second mechanical claw are symmetrically arranged on the left side of the material turntable, and the freezing box and the conveyor belt are located on the left side of the assembly platform.

[0013] An automated assembly method for an assembly platform of an assembly process for a pressure sensor comprises the following steps: Step 1, the first mechanical claw grabs the pressure sensor from the feeding tray and installs it on the material turntable; Step 2: The material turntable rotates counterclockwise to send the pressure sensor to the second mechanical claw position, and the conveyor belt transports the frozen antifreeze plug to the second mechanical claw position, and the second mechanical claw grabs the frozen antifreeze plug to the drainage hole of the pressure sensor; Step 3: The material turntable rotates counterclockwise to send the pressure sensor to the position of the pressing device, the control tool fixes the pressure sensor, and the driving unit drives the pressing rod to press down so that the tube is blocked and penetrates into the drainage hole; Step 4: The material turntable rotates counterclockwise to send the pressure sensor to the position of the CCD detector to detect whether the depth of the frozen plug in the drainage hole meets the standard. If not, the material sensor rotates clockwise to send the pressure sensor to the position of the pressing device and repeats steps 3 and 4 until the depth of the frozen plug in the drainage hole meets the standard. Step 5: The first mechanical claw grabs the assembled pressure sensor and puts it into the discharge tray.

[0014] Compared with the prior art, the advantages of the present invention are as follows: 1. The present invention reduces the size of the antifreeze plug, makes it brittle, and forms a frost layer on the surface that reduces friction, thereby reducing the difficulty of installing the antifreeze plug deep into the drainage hole and eliminating the need to apply lubricant on the surface of the antifreeze plug; 2. The present invention allows the antifreeze plug to go deeper into the drainage hole by inserting the rod, thereby preventing the antifreeze plug from popping out of the drainage hole; 3. The present invention implements an automated assembly process through an assembly platform, which has the advantages of ensuring consistent assembly quality and improving assembly efficiency; 4. The present invention sets the positions of the pressing device, the depth detection device, the first mechanical claw and the second mechanical claw in the assembly platform so that the material turntable can quickly complete the assembly and detection process by rotating counterclockwise, thereby further improving the assembly efficiency; 5. The present invention utilizes the moisture in the air to naturally condense a frost layer when freezing the antifreeze plug, which contains little moisture. After thawing, the moisture evaporates naturally and will not remain in the drainage hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a flow chart of the assembly process of the present invention; Figure 2 It is a structural diagram of the assembly platform of the present invention; Figure numerals: 1. Assembly platform; 2. Material turntable; 3. Pressing device; 4. Depth detection device; 5. First mechanical claw; 6. Second mechanical claw; 7. Freezer; 8. Conveyor belt; 9. Feed tray; 10. Discharge tray; 11. Material conveying rack. DETAILED DESCRIPTION

[0016] The technical solution of the invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the invention, rather than all of the embodiments.

[0017] Based on the embodiments of the invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the invention.

[0018] In the description of the invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the invention and simplifying the description, rather than indicating or implying that the device or element referred to has a specific orientation, is constructed and operated in a specific orientation, and therefore cannot be understood as limiting the invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0019] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances. Example 1

[0020] like Figure 1 As shown, the assembly process of the pressure sensor includes the following steps: Step a, placing the antifreeze plug made of elastic material in a low temperature environment and freezing it until the antifreeze plug shrinks to a size smaller than the aperture of the drainage hole of the pressure sensor, the property of the antifreeze plug changes from elastic to brittle, and a frost layer with a thickness of 3 to 5 mm condenses on the surface, preferably, the thickness of the frost layer is 3 mm; the glass transition temperature of the antifreeze plug is Tg, the brittle temperature of the antifreeze plug is Tb, and the freezing temperature t of the antifreeze plug is Tg≤t<Tb; preferably, t is -40°C. Specifically, the freezing time of the antifreeze plug is greater than 10 minutes.

[0021] Step b, fixing the pressure sensor with its drainage hole opening facing upward; Step c, taking out the frozen antifreeze plug and putting it into the drainage hole, reducing the friction between the antifreeze plug and the drainage hole through the frost layer on the surface of the antifreeze plug, so that the antifreeze plug can be quickly lowered and prevent the antifreeze plug from being stuck in the drainage hole; Step d, inserting the pressure rod into the drainage hole to further penetrate the antifreeze plug; Step e, detecting whether the depth of the antifreeze plug in the drainage hole meets the standard, if not, repeating steps d and e until it meets the standard; Step f, waiting for the antifreeze plug to thaw and restore its original size and elasticity, so that the antifreeze plug and the inner wall of the drainage hole are elastically squeezed and fixed, and the antifreeze plug expands and restores its original size after thawing, and the size of the antifreeze plug is larger than the aperture of the drainage hole. Example 2

[0022] like Figure 1 As shown, an assembly platform for an assembly process of a pressure sensor includes a horizontally arranged material turntable 2, and a pressing device 3, a depth detection device 4, a first mechanical claw 5 and a second mechanical claw 6 are evenly distributed around the circumference of the material turntable 2, wherein the depth detection device 4 is a CCD detector; The pressing device 3 includes a pressing rod for pressing the antifreeze plug deep into the drainage hole, a driving unit for driving the pressing rod to move vertically, and a tool for fixing the pressure sensor; The assembly platform 1 is provided with a feeding tray 9 for placing a pressure sensor on the outside of the first mechanical claw 5; The assembly platform 1 is provided with a freezer box 7 on the outside of the second mechanical claw 6, and a conveyor belt 8 is connected between the freezer box 7 and the assembly platform 1; The assembly platform 1 is located outside the depth detection device 4 and is provided with a discharge tray 10 for receiving the assembled pressure sensors.

[0023] Furthermore, the depth detection device 4 and the first mechanical claw 5 are symmetrically arranged on the right side of the material turntable 2, and a material conveying rack 11 is provided on the right side of the assembly platform 1, and the material conveying rack 11 is respectively arranged with the feeding tray 9 and the discharging tray 10; The pressing device 3 and the second mechanical claw 6 are symmetrically arranged on the left side of the material turntable 2 , and the freezing box 7 and the conveyor belt 8 are located on the left side of the assembly platform 1 .

[0024] An automated assembly method for an assembly platform of an assembly process for a pressure sensor comprises the following steps: Step 1, the first mechanical claw 5 grabs the pressure sensor from the feeding tray 9 and installs it on the material turntable 2; Step 2, the material turntable 2 rotates counterclockwise to send the pressure sensor to the position of the second mechanical claw 6, the conveyor belt 8 transports the frozen antifreeze plug to the position of the second mechanical claw 6, and the second mechanical claw 6 grabs the frozen antifreeze plug to the drainage hole of the pressure sensor; Step 3, the material turntable 2 rotates counterclockwise to send the pressure sensor to the position of the pressing device 3, the control tool fixes the pressure sensor, and the driving unit drives the pressing rod to press down so that the tube is blocked and penetrates into the drainage hole; Step 4: The material turntable 2 rotates counterclockwise to send the pressure sensor to the position of the CCD detector to detect whether the depth of the frozen plug in the drainage hole meets the standard. If not, the material sensor rotates clockwise to send the pressure sensor to the position of the pressing device 3 and repeats steps 3 and 4 until the depth of the frozen plug in the drainage hole meets the standard. Step 5: The first mechanical claw 5 grabs the assembled pressure sensor and puts it into the discharge tray 10 .

[0025] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. The assembly process of the pressure sensor is characterized in that: The steps include: Step a, placing the antifreeze plug made of elastic material in a low temperature environment and freezing it until the antifreeze plug shrinks to a size smaller than the aperture of the drainage hole of the pressure sensor, the property of the antifreeze plug changes from elastic to brittle, and a frost layer with a thickness of 3 to 5 mm condenses on the surface; Step b, fixing the pressure sensor with its drainage hole opening facing upward; Step c, taking out the frozen antifreeze plug and putting it into the drainage hole, reducing the friction between the antifreeze plug and the drainage hole through the frost layer on the surface of the antifreeze plug, so that the antifreeze plug can be quickly lowered and prevent the antifreeze plug from being stuck in the drainage hole; Step d, inserting the pressure rod into the drainage hole to further penetrate the antifreeze plug; Step e, detecting whether the depth of the antifreeze plug in the drainage hole meets the standard, if not, repeating steps d and e until it meets the standard; Step f, waiting for the antifreeze plug to thaw and restore its original size and elasticity, so that the antifreeze plug is elastically squeezed and fixed to the inner wall of the drainage hole.

2. The pressure sensor assembly process according to claim 1, characterized in that: In the step f, the antifreeze plug expands and returns to its original size after thawing, and the size of the antifreeze plug is larger than the aperture of the drainage hole.

3. The assembly process of the pressure sensor according to claim 2, characterized in that: In step a, the glass transition temperature of the antifreeze plug is Tg, the brittle temperature of the antifreeze plug is Tb, and the freezing temperature t of the antifreeze plug is Tg≤t<Tb.

4. The pressure sensor assembly process according to claim 3, characterized in that: The t is -40°C.

5. The assembly process of the pressure sensor according to claim 4, characterized in that: In the step a, the freezing time of the antifreeze plug is greater than 10 minutes.

6. An assembly platform for an assembly process of a pressure sensor according to claim 5, and an assembly process of a pressure sensor, characterized in that: It comprises a horizontally arranged material turntable (2), wherein a pressing device (3), a depth detection device (4), a first mechanical claw (5) and a second mechanical claw (6) are evenly distributed in the circumference of the material turntable (2); The pressing device (3) comprises a pressing rod for pressing the antifreeze plug to penetrate into the drainage hole, a driving unit for driving the pressing rod to move vertically, and a tool for fixing the pressure sensor; The assembly platform (1) is located outside the first mechanical claw (5) and is provided with a feeding tray (9) for placing a pressure sensor; The assembly platform (1) is provided with a freezer box (7) located outside the second mechanical claw (6), and a conveyor belt (8) is connected between the freezer box (7) and the assembly platform (1); The assembly platform (1) is located outside the depth detection device (4) and is provided with a discharge tray (10) for receiving assembled pressure sensors.

7. The assembly platform of the pressure sensor assembly process according to claim 6, characterized in that: The depth detection device (4) is a CCD detector.

8. The assembly platform of the assembly process of the pressure sensor according to claim 7, characterized in that: The depth detection device (4) and the first mechanical claw (5) are symmetrically arranged on the right side of the material turntable (2); a material conveying rack (11) is arranged on the right side of the assembly platform (1); and the material conveying rack (11) is respectively arranged with the feeding tray (9) and the discharging tray (10); The pressing device (3) and the second mechanical claw (6) are symmetrically arranged on the left side of the material turntable (2), and the freezing box (7) and the conveyor belt (8) are located on the left side of the assembly platform (1).

9. An automated assembly method for an assembly platform of an assembly process for a pressure sensor according to claim 8, characterized in that: The following steps are involved: Step 1, the first mechanical claw (5) grabs the pressure sensor from the feeding tray (9) and installs it on the material turntable (2); Step 2, the material turntable (2) rotates counterclockwise to send the pressure sensor to the position of the second mechanical claw (6), the conveyor belt (8) transports the frozen antifreeze plug to the position of the second mechanical claw (6), and the second mechanical claw (6) grabs the frozen antifreeze plug and puts it into the drainage hole of the pressure sensor; Step 3, the material turntable (2) rotates counterclockwise to send the pressure sensor to the position of the pressing device (3), the control tool fixes the pressure sensor, and the driving unit drives the pressing rod to press down so that the tube is blocked and penetrates into the drainage hole; Step 4, the material turntable (2) rotates counterclockwise to send the pressure sensor to the position of the CCD detector to detect whether the depth of the frozen plug in the drainage hole meets the standard. If not, the material sensor rotates clockwise to send the pressure sensor to the position of the pressing device (3) and repeats steps 3 and 4 until the depth of the frozen plug in the drainage hole meets the standard. Step 5: The first mechanical claw (5) grabs the assembled pressure sensor and puts it into the discharge tray (10).

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