Engine knock sensor

Abstract

The application discloses an engine knock sensor, which comprises a carrier and an insulating shell. The carrier is composed of a base and a sleeve coaxially extending from the top of the base. The sleeve is sequentially sleeved with a first insulating ring, two conductive rings, a second insulating ring, a counterweight ring and a nut from bottom to top. A piezoelectric ceramic is arranged between the two conductive rings. The nut is threadedly connected with the sleeve and abuts against the top of the counterweight ring. The two conductive rings are respectively connected with metal inserts on the same side. The metal inserts are sequentially composed of a connecting portion, a transition portion and a pin. The connecting portion is horizontally connected with the conductive ring. The pin is obliquely extended relative to the connecting portion. The transition portion is provided with at least one connecting hole. The insulating shell covers and fixes the carrier, the first insulating ring, the conductive ring, the second insulating ring, the counterweight ring, the nut and the metal insert together, so that the area of external liquid entering the product can be reduced, and the use reliability of the engine knock sensor is improved.

Description

Technical Field

[0001] This utility model relates to the field of sensor equipment technology, and in particular to an engine knock sensor. Background Technology

[0002] A knock sensor is an electronic sensor mounted on the engine block to measure engine vibration. It is used to adjust the ignition timing when engine knock occurs.

[0003] Traditional knock sensors typically employ a pin assembly, usually consisting of two metal pins with a width of approximately 4.7mm-4.9mm. The conductive ring leads, resistor, and metal pins are then thermocoupled in a stacked structure to form a fixed assembly. However, during the thermofusion welding process, due to the different materials, the metal and liquid plastic do not adhere completely, leaving a gap. During use, external liquids such as rainwater, antifreeze, and engine oil can easily enter the product through this gap, leading to product failure. Utility Model Content

[0004] This application provides an engine knock sensor that can reduce the area of ​​external liquid entering the product and improve the reliability of the engine knock sensor.

[0005] This application provides an engine knock sensor, including a carrier and an insulating housing. The carrier consists of a base and a sleeve extending coaxially from the top of the base. The sleeve is fitted with a first insulating ring, two conductive rings, a second insulating ring, a counterweight ring, and a nut from bottom to top. A piezoelectric ceramic is disposed between the two conductive rings. The nut is threaded to the sleeve and abuts against the top of the counterweight ring. Metal inserts are respectively connected to the two conductive rings on the same side. The metal inserts are composed of a connecting part, a transition part, and a pin in sequence. The connecting part is horizontally connected to the conductive ring, and the pin extends obliquely relative to the connecting part. The transition part has at least one connecting hole. The insulating housing covers and fixes the carrier, the first insulating ring, the conductive ring, the second insulating ring, the counterweight ring, the nut, and the metal inserts together.

[0006] In one possible implementation, the transition portion is a transition plate, and both ends of the transition portion are connected to the connecting portion and the pin respectively through arc-shaped plates, with the connecting hole formed on the transition plate.

[0007] In one possible implementation, the connection holes have 1 to 3.

[0008] In one possible implementation, the arc plate includes a first arc plate and a second arc plate. The transition portion is connected to the connecting portion through the first arc plate and to the pin through the second arc plate. The width of the first arc plate is equal to the width of the transition portion. The second arc plate has chamfers symmetrically provided at both ends in the thickness direction, such that the width of the transition portion is greater than the width of the pin.

[0009] In one possible implementation, the width of the transition portion is 6.5-8.3 mm.

[0010] In one possible implementation, the base has a base cavity that extends coaxially with the cavity of the sleeve, and the bottom of the base gradually concaves inward from the outer circumference to the base cavity in an inclined plane.

[0011] In one possible implementation, the bottom of the base has an angle of 0.4 degrees to 1.0 degrees with respect to the horizontal plane.

[0012] Beneficial effects: Compared with the prior art, the engine knock sensor provided in this application opens a connection hole at the transition part of the metal insert, which allows the plastic solution to fill the connection hole during the welding process. This not only reduces the gap area between the cooled metal insert and the plastic, thus reducing the probability of external liquid entering the product during subsequent use, but also improves the overall structural stability of the sensor based on the connection hole and the role of the plastic inside the connection hole. The concave, inclined design at the bottom of the base allows the sensor to better fit the cylinder surface when bolted, thereby enhancing the strength of the engine knock signal transmission.

[0013] These and other objects, features and advantages of this utility model will be fully realized through the following detailed description. Attached Figure Description

[0014] Figure 1 A three-dimensional structural schematic diagram of the engine knock sensor of this application is shown.

[0015] Figure 2 A cross-sectional view of the engine knock sensor of this application is shown.

[0016] Figure 3 This application shows Figure 2 A magnified structural diagram of part A in the middle.

[0017] Figure 4 A three-dimensional structural schematic diagram of the carrier in this application is shown.

[0018] Figure 5 A three-dimensional structural schematic diagram of the metal insert in this application is shown. Detailed Implementation

[0019] The following description is intended to disclose the present invention so that those skilled in the art can implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the present invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the present invention.

[0020] Those skilled in the art should understand that, in the disclosure of this specification, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limitations on this utility model.

[0021] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0022] refer to Figures 1 to 5 This application provides an engine knock sensor, including a carrier 10 and an insulating housing 20. The carrier 10 consists of a base 11 and a sleeve 12 extending coaxially from the top of the base 11. The sleeve 12 is fitted with a first insulating ring 31, two conductive rings 32, a second insulating ring 33, a counterweight ring 34, and a nut 35 from bottom to top. A piezoelectric ceramic 36 is disposed between the two conductive rings 32. The nut 35 is threaded to the sleeve 12 and abuts against the top of the counterweight ring 34. Metal inserts 37 are connected to the two conductive rings 32 on the same side. The metal inserts 37 consist of a connecting portion 371, a transition portion 372, and a lead 373. The connecting portion 371 is horizontally connected to the conductive rings 32, and the lead 373 extends obliquely relative to the connecting portion 371. The transition portion 372 has at least one connecting hole 301. The insulating shell 20 covers and fixes the carrier 10, the first insulating ring 31, the conductive ring 32, the second insulating ring 33, the counterweight ring 34, the nut 35 and the metal insert 37 together.

[0023] The assembly process of the engine knock sensor is as follows: S10. First, put the first insulating ring 31, two conductive rings 32, piezoelectric ceramic 36, second insulating ring 33, and counterweight ring 34 onto the sleeve 12 of the carrier 10 in sequence, so that the axes of all parts coincide and form a central cavity, that is, the cavity of the sleeve 12. Then ensure that the conductive ring pins are in the same direction and are equidistant and symmetrical. S20. Insert the nut 35 into the sleeve 12 by engaging the threads. S30. Use a torque wrench to fix all parts together to form a fixed body. S40. Using a mold, the conductive ring 32 and the metal insert 37 are hot-melted and welded according to the stacked structure to form a fixed body two. S50. Molten insulating plastic fluid is injected into the injection mold and injected into the central cavity of the first fixed body through the notch of the conductive ring 32 under the action of injection pressure, and cooled to form the first fixed body. Under the action of the injection mold, the fluid is injected into the symmetrical cavity of the second fixed body and cooled to form the second fixed body. S60, wrapping the fixing body two and retaining the exposed pins of the insert group to form an insulating shell 20.

[0024] Since the transition portion 372 of the metal insert 37 has a connection hole 301, the plastic will automatically fill the connection hole 301 during the flow of the insulating plastic fluid. In this way, after cooling, the gap area between the metal insert 37 and the plastic will be reduced (in the prior art, there is a gap between the metal insert and the plastic). In subsequent use, the probability of external liquid entering the sensor product will be reduced, and the reliability of the engine knock sensor will be improved. At the same time, based on the role of the connection hole 301 and the plastic inside the connection hole 301, the overall structural stability of the sensor can also be improved.

[0025] In one embodiment, the transition portion 372 is a transition plate or a plate. The two ends of the transition portion 372 are connected to the connecting portion 371 and the pin 373 respectively through arc-shaped plates 38 to ensure the continuity and structural stability of the overall structure of the metal insert 37. At the same time, the connecting hole 301 is formed on the transition plate 372 to facilitate the opening.

[0026] In one embodiment, the connection hole 301 has 1 to 3 holes.

[0027] In one embodiment, the arc plate 38 includes a first arc plate 381 and a second arc plate 382. The transition portion 372 is connected to the connecting portion 371 through the first arc plate 381 and to the pin 373 through the second arc plate 382. The width of the first arc plate 381 is equal to the width of the transition portion 382. The second arc plate 382 has chamfers symmetrically provided at both ends in the thickness direction, so that the width of the transition portion 372 is greater than the width of the pin 373. This increases the width of the transition portion 372 and the first arc plate 381, which can increase or extend the path for external liquid to enter the sensor, thereby further reducing the probability of external liquid entering the sensor product and improving the reliability of the engine knock sensor.

[0028] In one embodiment, the width of the transition portion 372 is 6.5-8.3 mm. This width is approximately 45% larger than that of existing designs.

[0029] In one embodiment, the base 11 has a base cavity 101. The base cavity 101 extends coaxially with the cylindrical cavity of the sleeve 12, and the bottom of the base 11 gradually concaves inward from the outer circumference to the base cavity 101. Simulation of the carrier deformation under sensor product installation torque using ANSYS simulation technology reveals that using bolts (e.g., M8 bolts) with an installation torque of 11 Nm in the base cavity and cylindrical cavity allows for better contact with the cylinder surface, thereby reducing the attenuation of engine knock signal transmission intensity and improving knock detection accuracy. During the experiment, the clamping condition was that the bottom of the base 11 first contacted the mounting surface, distributed force positioning was applied, and a force of 8500 N was applied to the top of the sleeve 12 in the Z-axis direction, with a torque of 11 Nm applied to the carrier 10. Using calculation tools, the force applied to the bolts was calculated, and the maximum deformation displacement of the carrier 10 was 3 mm, the maximum concavity of the carrier 10 was 0.0258, and the concavity value of the top of the sleeve 12 was 0.0152.

[0030] For M8 bolts, according to ISO 898_7en (torsion test), the minimum breaking torque for performance class 8.8 is 13 Nm. According to the torsion test standard, the breaking torque for grade 8.8 bolts is 24.5 Nm. Therefore, using 11 Nm bolts of M8-8.8 grade is safe.

[0031] In one embodiment, the bottom of the base 11 has an angle α of 0.4 degrees to 1.0 degrees with respect to the horizontal plane.

[0032] It should be noted that the terms "first" and "second" used in this application are for descriptive purposes only and do not indicate any order. They should not be construed as indicating or implying relative importance, and can be interpreted as names.

[0033] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are merely examples and do not limit the present invention. The advantages of the present invention have been fully and effectively realized. The functions and structural principles of the present invention have been shown and explained in the embodiments, and any modifications or variations may be made to the implementation of the present invention without departing from the stated principles.

Claims

1. An engine knock sensor, characterized in that, The device includes a carrier and an insulating shell. The carrier consists of a base and a sleeve extending coaxially from the top of the base. The sleeve is fitted with a first insulating ring, two conductive rings, a second insulating ring, a counterweight ring, and a nut from bottom to top. A piezoelectric ceramic is disposed between the two conductive rings. The nut is threaded to the sleeve and abuts against the top of the counterweight ring. Metal inserts are connected to the two conductive rings on the same side. Each metal insert consists of a connecting part, a transition part, and a pin. The connecting part is horizontally connected to the conductive ring, and the pin extends at an angle relative to the connecting part. The transition part has at least one connecting hole. The insulating shell covers and fixes the carrier, the first insulating ring, the conductive ring, the second insulating ring, the counterweight ring, the nut, and the metal inserts together.

2. The engine knock sensor as described in claim 1, characterized in that, The transition section is a transition plate, and its two ends are connected to the connecting section and the pin respectively through arc-shaped plates. The connecting hole is formed on the transition plate.

3. The engine knock sensor as described in claim 2, characterized in that, The number of connection holes is 1 to 3.

4. The engine knock sensor as described in claim 2, characterized in that, The arc-shaped plate includes a first arc-shaped plate and a second arc-shaped plate. The transition portion is connected to the connecting portion through the first arc-shaped plate and to the pin through the second arc-shaped plate. The width of the first arc-shaped plate is equal to the width of the transition portion. The second arc-shaped plate has chamfers symmetrically provided at both ends in the thickness direction, so that the width of the transition portion is greater than the width of the pin.

5. The engine knock sensor as described in claim 4, characterized in that, The width of the transition section is 6.5-8.3 mm.

6. The engine knock sensor as described in claim 1, characterized in that, The base has a base cavity, which extends coaxially with the cylinder cavity of the sleeve. The bottom of the base gradually indents inward from the outer circumference to the base cavity.

7. The engine knock sensor as described in claim 6, characterized in that, The bottom of the base has an angle of 0.4 degrees to 1.0 degrees with respect to the horizontal plane.

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