JP2020003414A - Knocking sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a knocking sensor capable of suppressing infiltration of water containing calcium chloride or the like into a main body even when the sensor is mounted at a sensor mounting position where water containing calcium chloride or the like easily adheres. SOLUTION: One aspect of the present disclosure is a knocking sensor for detecting knocking of an internal combustion engine, which includes a main body portion, a cover portion, and a covering portion. The covering portion covers at least a specific boundary portion which is a portion of the contact boundary that overlaps with the virtual extension region and is close to the connector portion. Since this knocking sensor is provided with a covering portion, water containing calcium chloride or the like infiltrates into the main body portion of the knocking sensor from a specific boundary portion of the boundary between the main body portion and the cover portion (specifically, the main body storage portion). It can be suppressed. Therefore, this knocking sensor can suppress the infiltration of water containing calcium chloride or the like into the main body. [Selection diagram] Fig. 3

Description

  The present disclosure relates to a knocking sensor.

  The knocking sensor is mounted on an internal combustion engine (a diesel engine, a gasoline engine, or the like) and is used for detecting knocking of the internal combustion engine. The knocking sensor includes a main body that outputs a detection signal that varies according to vibration transmitted from the internal combustion engine, and a resin cover formed around the main body.

  The knocking knocker is fixed to the sensor mounting position of the internal combustion engine, for example, by fixing it to a mounting screw hole provided at a sensor mounting position of the internal combustion engine using a mounting bolt screwed into the mounting screw hole. You.

  As a knocking sensor, there has been proposed a knocking sensor having a sensor receiving portion disposed between the knocking sensor and the mounting screw hole so as to be able to cope with various mounting screw holes having different sizes (Patent Document 1). By replacing the sensor receiving portion, such a knocking sensor can be mounted on various types of internal combustion engines having different dimensions of the mounting screw holes without changing the outer shape of the knocking sensor main body.

JP-A-11-201813

  However, the knocking sensor described above may be mounted at a sensor mounting position where water containing calcium chloride or the like easily adheres, and in such a case, the knocking sensor is damaged by the influence of water containing calcium chloride or the like. there is a possibility.

  For example, when water containing calcium chloride adheres to the knocking sensor, the resin cover part deteriorates due to the influence of calcium chloride, causing cracks, and water containing calcium chloride or the like is further transmitted to the main body through the cracks. There is a possibility that the main body may break down.

  Therefore, the present disclosure provides a knocking sensor that can suppress entry of water containing calcium chloride or the like into a main body even when the sensor is mounted at a sensor mounting position where water containing calcium chloride or the like easily adheres. Is desirable.

One embodiment of the present disclosure is a knocking sensor that detects knocking of an internal combustion engine, and includes a main body, a cover, and a cover.
The main body generates a detection signal that varies according to knocking. The main body includes a contact part, a detection part, and a terminal part. The contact portion is a portion that contacts the internal combustion engine. The detection unit generates a signal that fluctuates according to the vibration transmitted through the contact unit as a detection signal. The terminal outputs the detection signal to the outside.

  The cover is a resin member formed around the main body. The cover section includes a main body storage section and a connector section. The main body storage unit covers the detection unit with the contact unit exposed. The connector portion covers the terminal portion and extends outward from the main body storage portion.

  Here, when the knocking sensor is viewed from the contact portion side, a virtual region obtained by extending the formation region of the connector portion in the extending direction of the connector portion is defined as a virtual extension region. In addition, a boundary between the main body and the main body storage is defined as a contact boundary.

The covering portion covers at least a specific boundary portion of the contact boundaries. The specific boundary portion is a portion of the contact boundary that overlaps the virtual extension region and is close to the connector portion.
Since the knocking sensor includes the covering portion, water containing calcium chloride or the like intrudes into the main body of the knocking sensor from a specific boundary portion of the boundary between the main body portion and the cover portion (specifically, the main body storage portion). Can be suppressed. In particular, the intrusion of water containing calcium chloride or the like from the specific boundary portion can be suppressed, so that the water containing calcium chloride or the like can reach the terminal portion of the main body.

  Therefore, even when the knocking sensor is mounted at a sensor mounting position where water containing calcium chloride or the like is likely to adhere, it is possible to suppress entry of water containing calcium chloride or the like into the main body.

  Next, in the knocking sensor described above, the covering portion may cover the entire contact boundary. Thus, the intrusion of water containing calcium chloride or the like can be suppressed over the entire area of the contact boundary, so that the intrusion of water containing calcium chloride or the like into the main body of the knocking sensor can be further suppressed.

Next, in the knocking sensor described above, the covering portion may cover the entire surface including the contact boundary on the outer surface of the cover portion.
By providing the covering portion that covers the entire plane including the contact boundary on the outer surface of the cover portion in this manner, when water containing calcium chloride or the like enters between the sensor installation location and the knocking sensor, Also, since the plane including the contact boundary is covered by the covering portion, it is possible to prevent water containing calcium chloride or the like from contacting the cover portion (particularly, the plane including the contact boundary). Therefore, this knocking sensor can suppress the deterioration of the cover part due to the influence of water containing calcium chloride or the like.

  Next, in the knocking sensor described above, the material forming the cover may be a material having a higher heat-resistant temperature than the material forming the covering. Thus, the main body can be protected by the cover even in a higher temperature environment. For example, the knocking sensor is arranged even in a high temperature environment in which a high temperature object such as an exhaust pipe exists right above the knocking sensor. be able to.

It is a partial sectional view showing a knocking sensor unit. It is sectional drawing which shows the internal structure of a knocking sensor. FIG. 3A is an external view showing the appearance of the bottom surface side of the knocking sensor with the cover removed, and FIG. 3B is an explanatory diagram showing the appearance of the cover. FIG. 4A is an explanatory diagram of a specific boundary portion and a virtual extension region in the knocking sensor, and FIG. 4B is an explanatory diagram illustrating an appearance of a second covering portion. FIG. 5A is an explanatory diagram of a boundary plane in the knocking sensor, and FIG. 5B is an explanatory diagram illustrating an appearance of the third covering portion.

Hereinafter, embodiments to which the present disclosure is applied will be described with reference to the drawings.
In the embodiment described below, a knocking sensor that detects knocking of an internal combustion engine mounted on an automobile or the like will be described as an example.

[1. First Embodiment]
[1-1. overall structure]
First, a knocking sensor unit 1 including a knocking sensor 10 to which the present disclosure is applied will be described with reference to FIGS. 1 and 2.

  As shown in FIG. 1, the knocking sensor unit 1 includes a non-resonant knocking sensor 10 (hereinafter, also simply referred to as “knocking sensor 10”), a mounting bolt 50, and a cover 70.

[1-2. Knocking sensor]
The knocking sensor 10 includes a main body 10a and a cover 10b.
As shown in FIG. 2, the main body 10a includes a contact part 10a1, a detection part 10a2, and a terminal part 10a3. The contact portion 10a1 is a portion that contacts the internal combustion engine.

The detection unit 10a2 includes a support member 21, a lower surface side electrode member 34, a piezoelectric element 31, an upper surface side electrode member 36, a weight member 32, and a nut 33.
The support member 21 is made of, for example, a metal material (various metal materials such as carbon steel). The support member 21 includes a cylindrical tubular portion 22 that extends in the axial direction, and a flange portion 23 that protrudes radially outward from one end of the tubular portion 22.

  A through hole 24 penetrating in the axial direction is provided inside the cylindrical portion 22. Grooves 26 and 27 are provided on the outer peripheral surface of the cylindrical portion 22 near the upper end surface 28 and on the outer peripheral surface of the flange portion 23 for improving the adhesion to the cover portion 10b. On the lower surface side of the groove portion 26 (the lower side in FIG. 1; the same applies hereinafter) of the outer peripheral surface of the cylindrical portion 22, a thread groove 25 to be screwed with the nut 33 is provided.

  The piezoelectric element 31 includes a material having a piezoelectric effect (various ceramics such as lead zirconate titanate (PZT) and barium titanate, various crystals such as quartz, various organic materials such as polyvinylidene fluoride, and the like). ing. The piezoelectric element 31 is formed in an annular shape surrounding the outer periphery of the cylindrical portion 22. The piezoelectric element 31 is arranged on the upper surface side of the flange 23.

  The lower surface side electrode member 34 is made of a conductive material (such as copper) formed in an annular shape surrounding the outer periphery of the cylindrical portion 22. The lower surface side electrode member 34 is in contact with the lower surface of the piezoelectric element 31. The upper surface side electrode member 36 is made of a conductive material (such as copper) formed in an annular shape surrounding the outer periphery of the cylindrical portion 22. The upper surface side electrode member 36 is in contact with the upper surface of the piezoelectric element 31.

  The weight member 32 is formed using an annular metal material (various metal materials such as brass). The weight member 32 is arranged on the upper surface side of the upper electrode member 36 so as to surround the outer periphery of the cylindrical portion 22. The weight member 32 is provided for applying a load to the piezoelectric element 31.

  The nut 33 is formed of an annular metal material. The nut 33 is formed with a screw groove (not shown) for screwing with the screw groove 25 of the cylindrical portion 22 on the inner peripheral surface, so that the nut 33 can be screwed and fixed to the cylindrical portion 22. The nut 33 has a polygonal (for example, hexagonal) outer peripheral shape in a plane perpendicular to the axial direction, and is configured to be fastened and fixed using a tool or the like.

  The terminal 10a3 includes a first terminal 35 and a second terminal 37. The first terminal portion 35 is made of a conductive material (such as copper) extending from the lower electrode member 34. The first terminal portion 35 is used as a current path for an electric signal output from the lower surface of the piezoelectric element 31. The second terminal portion 37 is made of a conductive material (such as copper) extending from the upper electrode member 36. The second terminal part 37 is used as a current path for an electric signal output from the upper surface of the piezoelectric element 31.

  The cover 10b is formed around the main body 10a. The cover portion 10b is formed using an insulating material (a variety of resin materials such as PA (polyamide)). The cover section 10b includes a main body storage section 13 and a connector section 15.

  The main body storage portion 13 has a cylindrical shape in which an upper surface side (the upper side in FIG. 1; the same applies hereinafter) is formed into a tapered shape. The main body storage unit 13 covers the detection unit 10a2 with the upper end surface 28 of the support member 21 exposed and the lower end surface 29 (in other words, the contact part 10a1) exposed.

  The connector section 15 extends outward from the outer peripheral wall of the main body storage section 13. The connector section 15 is provided for connecting an external connector connected to an external device (for example, an ignition timing control device). The connector part 15 is formed such that a part of the first terminal part 35 and the second terminal part 37 is exposed inside. The first terminal 35 and the second terminal 37 are electrically connected to an external connector.

[1-3. Mounting bolt]
As shown in FIG. 1, the mounting bolt 50 includes a head portion 51 having a hexagonal outer peripheral shape on a surface perpendicular to the axial direction, a body portion 53 formed in a round bar shape, and a body portion 53 of the head portion 51. And a pressing portion 52 formed on the side. In the mounting bolt 50, a male screw portion 54 is formed on the tip side (the side opposite to the head portion 51) of the body portion 53.

[1-4. Covering part]
Next, the covering portion 70 will be described with reference to FIGS. 1, 2, 3A, 3B, and 4. FIG.
As shown in FIG. 3B, the covering portion 70 is formed in an annular shape having an insertion hole 70a. The cover 70 is made of a resin material (for example, PET). The inner diameter A1 of the insertion hole 70a is 19.9 mm, and the outer diameter A2 of the cover 70 is 28.3 mm. As shown in FIG. 2, the thickness dimension H1 of the covering portion 70 is 0.29 mm.

  As shown in FIGS. 2 and 3A, in the main body 10a, the outer diameter L1 of the contact portion 10a1 is 20.0 mm, the outer diameter L2 of the flange 23 is 23.0 mm, and The height H2 from the end surface to the contact surface (lower end surface 29) of the contact portion 10a1 is 0.30 mm. The outer diameter L3 of the main body storage portion 13 of the cover portion 10b is 28.0 mm.

  On the lower surface side of the knocking sensor 10, there is provided a contact boundary 41 which is a boundary between the main body 10a (specifically, the flange 23) and the cover 10b (specifically, the main body storage 13). In the knocking sensor 10 of the present embodiment, the contact boundary 41 is circular. The outer diameter of the contact boundary 41 is equal to the outer diameter L2 (= 23.0 mm) of the flange 23.

  The inside diameter A1 (= 19.9 mm) of the insertion hole 70a is slightly smaller than the outside diameter L1 (= 20.0 mm) of the contact portion 10a1 (difference value D = 0.1 mm). Therefore, when the insertion hole 70a is fitted on the outer periphery of the contact portion 10a1, the covering portion 70 is fixed to the main body portion 10a by the contraction force of the covering portion 70.

  The outer diameter A2 (= 28.3 mm) of the cover 70 is larger than the outer diameter L3 (= 28.0 mm) of the main body storage section 13 of the cover 10b. For this reason, the covering part 70 is fixed to the main body part 10a while covering the bottom surface of the main body storage part 13 of the cover part 10b.

In this manner, the covering portion 70 is fixed to the main body portion 10a in a state of covering the entire periphery of the contact boundary 41 by fitting the insertion hole 70a to the outer periphery of the contact portion 10a1.
The thickness H1 (= 0.29 mm) of the covering portion 70 is smaller than the height H2 (= 0.30 mm) from the lower end surface of the flange portion 23 to the contact surface of the contact portion 10a1. For this reason, even when the covering part 70 is arranged, the contact part 10a1 of the main body part 10a reliably comes into contact with the internal combustion engine (location where the knocking sensor 10 is installed).

  The heat-resistant temperature T1 (melting point T1) of the resin material (PET) forming the covering portion 70 is 260 ° C., and the heat-resistant temperature T2 (melting point T2) of the resin material (PA) forming the cover portion 10b is 265 ° C. That is, the material forming the cover portion 10b is a material having a higher heat resistance temperature than the material forming the cover portion 70.

[1-5. How to attach knocking sensor unit]
In the knocking sensor unit 1 configured as described above, the lower surface of the knocking sensor 10 (specifically, the lower end surface 29 of the flange 23 of the support member 21) is attached to the sensor mounting position of the internal combustion engine in the process of assembling the engine. (For example, a cylinder block, etc., not shown), and attached to the internal combustion engine by the attachment bolt 50.

  In addition, as a mounting method, a method of screwing the male screw portion 54 of the mounting bolt 50 with a female screw groove formed in the internal combustion engine is exemplified. At this time, since the upper end surface 28 of the knocking sensor 10 (support member 21) comes into close contact with the pressing portion 52 of the mounting bolt 50, the knocking sensor 10 is firmly attached to the internal combustion engine by the mounting bolt 50. It will be in a fixed state.

  In the knocking sensor 10 fixed to the internal combustion engine in this way, when abnormal vibration such as knocking occurs in the internal combustion engine, the abnormal vibration reaches the piezoelectric element 31 via the flange 23 of the support member 21. Then, knocking sensor 10 outputs an electric signal generated by piezoelectric element 31 in response to the abnormal vibration from first terminal portion 35 and second terminal portion 37 to an external device.

[1-6. effect]
As described above, the knocking sensor 10 in the knocking sensor unit 1 of the present embodiment includes the main body 10a and the cover 10b, and also includes the covering 70.

  The knocking sensor 10 is configured such that the covering portion 70 covers the entire periphery of the contact boundary 41 that is the boundary between the main body 10a and the cover 10b (specifically, the main body storage 13). For this reason, by providing the knocking sensor 10 with the covering portion 70, it is possible to prevent water including calcium chloride such as water from entering the main body 10 a of the knocking sensor 10 from the contact boundary 41.

  Therefore, even when knocking sensor 10 is mounted at a sensor mounting position where water containing calcium chloride or the like is likely to adhere, water containing calcium chloride or the like can be suppressed from entering into main body 10a.

  Next, in the knocking sensor 10, the material forming the cover portion 10b is a material having a higher heat-resistant temperature than the material forming the covering portion 70. Thereby, the main body 10a can be protected by the cover 10b even in a higher temperature environment. For example, even in a high temperature environment in which a high temperature object such as an exhaust pipe exists directly above the knocking sensor 10, the knocking sensor 10 can be arranged.

[1-7. Correspondence of wording]
Here, the correspondence between words will be described.
The non-resonant knocking sensor 10 corresponds to an example of a knocking sensor, the main body 10a corresponds to an example of a main body, the contact portion 10a1 corresponds to an example of a contact portion, and the detecting portion 10a2 corresponds to an example of a detecting portion. The first terminal portion 35 and the second terminal portion 37 correspond to an example of the terminal portion. The cover portion 10b corresponds to an example of the cover portion, the main body storage portion 13 corresponds to an example of the main body storage portion, and the connector portion 15 corresponds to an example of the connector portion. The covering portion 70 corresponds to an example of the covering portion, and the contact boundary 41 corresponds to an example of the contact boundary.

[2. Other Embodiments]
Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and can be implemented in various modes without departing from the gist of the present disclosure.

  For example, in the above-described embodiment, the knocking sensor in which the covering portion 70 covers the entire contact boundary 41 has been described. However, the present invention is not limited to such a form, and the covering portion covers a part of the contact boundary 41. It may be in the form of covering. Specifically, as shown in FIGS. 4A and 4B, knocking sensor 10 in a form including second covering portion 71 that covers at least specific boundary portion 41 a (portion shown by a thick line in FIG. 4A) of contact boundary 41. It may be.

  Note that the specific boundary portion 41a is a portion of the contact boundary 41 that overlaps with the virtual extension region M1 (the hatched region in FIG. 4A) of the connector portion 15 in the knocking sensor 10, and is a portion close to the connector portion 15. . The virtual extension region M1 of the connector portion 15 is a direction in which the formation region of the connector portion 15 when the knocking sensor 10 is viewed from an axial direction perpendicular to the contact portion 10a1 extends in a direction in which the connector portion 15 extends toward the contact portion 10a1. Is a virtual area extended to

  The second covering portion 71 is made of the same resin material as the covering portion 70 (for example, PET or the like). The second covering portion 71 covers the specific boundary portion 41a of the contact boundary 41, and is in contact with a part of the outer peripheral side surface of the contact portion 10a1 in a state where the heat-resistant adhesive (for example, Loctite (registered trademark), It is fixed to the main body 10a using a high heat resistant silicone sealant.

  As described above, the knocking sensor 10 including the second covering portion 71 has an abutment between the main body portion 10a and the cover portion 10b (specifically, the main body storage portion 13) because the second covering portion 71 covers the specific boundary portion 41a. Water containing calcium chloride or the like can be suppressed from entering the main body 10a of the knocking sensor 10 from the specific boundary 41a of the boundary 41. In particular, since intrusion of water containing calcium chloride or the like from the specific boundary portion 41a can be suppressed, it is possible to suppress water containing calcium chloride or the like from reaching the terminal portion 10a3 of the main body 10a.

  Therefore, even when the knocking sensor 10 including the second covering portion 71 is mounted at a sensor mounting position where water containing calcium chloride or the like is likely to adhere, water containing calcium chloride or the like enters the main body 10a. Can be suppressed. In the knocking sensor 10, the second covering portion 71 corresponds to an example of the covering portion.

  Next, as another embodiment, a knocking sensor including the third covering portion 72 as shown in FIGS. 5A and 5B may be used. The third covering portion 72 includes an annular portion 72a and an extension 72b. The annular portion 72a has the same shape as the covering portion 70 of the first embodiment. The extension part 72b protrudes outward from the side surface of the annular part 72a. The extended portion 72b has a shape corresponding to a part of the second covering portion 71.

  The third covering portion 72 covers the entire boundary plane M2 (the region shown by oblique lines in FIG. 5A) on the outer surface of the cover portion 10b. The boundary plane M2 is a plane area of the outer surface of the cover portion 10b whose axial height is the same as the specific boundary portion 41a. In the present embodiment, the boundary plane M2 indicates the “lower surface of the main body storage portion 13” and the “lower surface of the connector portion 15 located on the same plane as the lower surface of the main body storage portion 13” in the cover portion 10b.

  By providing the third covering portion 72 that covers the entire boundary plane M2 of the outer surface of the cover portion 10b in this way, water containing calcium chloride or the like enters between the sensor installation location of the internal combustion engine and the knocking sensor 10. Even in this case, since the boundary plane M2 is covered with the third covering portion 72, it is possible to prevent water containing calcium chloride or the like from coming into contact with the cover portion 10b (particularly, the boundary plane M2).

  Therefore, the knocking sensor 10 including the third covering portion 72 can suppress the deterioration of the cover portion 10b due to the influence of water containing calcium chloride or the like. In the knocking sensor 10, the third covering portion 72 corresponds to an example of the covering portion.

  Next, the dimensions (the inner diameter A1, the outer diameter A2, the outer diameter L1, the outer diameter L2, the outer diameter L3, the thickness H1, and the height H2) of the respective parts in the above embodiment are merely examples. , And these numbers can take any numerical values within the scope of the present disclosure. Further, the type of the material (such as the heat-resistant temperature) in the above embodiment is a numerical value in one embodiment, and can take any numerical value within the scope of the present disclosure.

  Next, the function of one component in the above embodiment may be shared between a plurality of components, or the function of the plurality of components may be exhibited by one component. Further, a part of the configuration of the above embodiment may be omitted. In addition, at least a part of the configuration of the above embodiment may be added to or replaced with the configuration of another above embodiment. Note that all aspects included in the technical idea specified by the language described in the claims are embodiments of the present disclosure.

  DESCRIPTION OF SYMBOLS 1 ... Knocking sensor unit, 10 ... Non-resonance type knocking sensor (knocking sensor), 10a ... Body part, 10a1 ... Contact part, 10a2 ... Detection part, 10a3 ... Terminal part, 10b ... Cover part, 13 ... Body storage part, 15 connector part, 21 support member, 22 tubular part, 23 flange part, 24 through hole, 28 upper end face, 29 lower end face, 35 first terminal part, 37 second terminal part, 41 ... contact boundary, 41a ... specific boundary part, 50 ... mounting bolt, 70 ... coating part, 70a ... insertion hole, 71 ... second coating part, 72 ... third coating part.

Claims (4)

A knocking sensor that detects knocking of an internal combustion engine,
A main body that generates a detection signal that varies according to the knocking;
A resin cover formed around the body,
With
The main body section includes a contact section that contacts the internal combustion engine, a detection section that generates a signal that fluctuates according to vibration transmitted through the contact section as the detection signal, and outputs the detection signal to the outside. Output terminal section,
The cover portion includes a main body storage portion that covers the detection portion in a state where the contact portion is exposed, and a connector portion that covers the terminal portion and extends outward from the main body storage portion,
When the knocking sensor is viewed from the contact portion side, a virtual region obtained by extending the formation region of the connector portion in a direction in which the connector portion extends is a virtual extension region, and a boundary between the main body portion and the main body storage portion. Is the contact boundary,
A covering portion that covers at least a specific boundary portion that is a portion of the contact boundary that overlaps the virtual extension region and that is close to the connector portion,
Knocking sensor. The covering portion covers all of the contact boundary,
The knocking sensor according to claim 1. The covering portion covers the entire surface including the contact boundary, of the outer surface of the cover portion,
The knocking sensor according to claim 1. The material forming the cover portion is a material having a higher heat-resistant temperature than the material forming the coating portion,
The knocking sensor according to any one of claims 1 to 3.

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