JP2010048734A - Pressure sensor for engine, pressure sensor unit, and manufacturing method of the pressure sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide technology capable of accurately making a resin member in mounting a pressure sensor for an engine on a cylinder head of the engine. <P>SOLUTION: A step is provided on a side face of a pipe member having a pressure detecting part provided at one end and a resin member fixed thereto. Such a constitution enables the step provided on the pipe member to be utilized in positioning for providing the resin member, whereby the resin member can be accurately provided. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an engine pressure sensor, a pressure sensor unit, and a pressure sensor manufacturing method.

  2. Description of the Related Art Pressure detection devices that detect pressure in an engine cylinder are known. For example, an ignition plug insertion gap is provided inside, and an integrated body including a piezoelectric element is accommodated in an inner flange, and the inner flange is held between a plug seat and an ignition plug, and an inner cylinder wall and an outer cylinder A configuration in which a lead wire connected to an electrode of a piezoelectric element is electrically drawn out from a peripheral gap between the wall and a wall is known.

Japanese Patent No. 3226374

  By the way, various resin members are provided in the pressure sensor. Examples of the resin member include a cap and a connector that outputs a detection signal. However, the fact that such a resin member is provided with high accuracy has not been sufficiently devised.

  SUMMARY An advantage of some aspects of the invention is to provide a technique capable of providing a resin member with high accuracy.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1] A pressure sensor for an engine, which has a side surface having a stepped portion and is provided at one end of the pipe member, and a pipe member that houses a spark plug when attached to the engine, A pressure sensor comprising: a pressure detection unit that is sandwiched between a seat for mounting the spark plug in the engine and the spark plug when mounted on the engine; and a resin member fixed to the pipe member. .

  According to this structure, since the step part provided in the pipe member can be used for positioning related to the provision of the resin member, the resin member can be provided with high accuracy.

[Application Example 2] The pressure sensor according to Application Example 1, wherein the resin member is fixed to the pipe member by insert molding.

  According to this structure, since the level | step-difference part provided in the pipe member can be utilized for the positioning in the case of performing insert molding, the resin member can be provided with high precision.

[Application Example 3] The pressure sensor according to Application Example 1 or Application Example 2, wherein the pipe member has N steps (N is an integer of 3 or more).

  According to this configuration, since three or more step portions can be used for positioning, it is easy to improve positioning accuracy related to the provision of the resin member.

[Application Example 4] The pressure sensor according to Application Example 3, wherein the N stepped portions are not overlapped with each other when viewed along the central axis of the pipe member. When arranged along the central axis, when viewed along the central axis, an angle with the central axis formed by two adjacent stepped portions and the central axis is an angle of the N stepped portions. Pressure sensors that are set the same for each.

  According to this configuration, when viewed along the central axis of the pipe member, the N step portions are isotropically arranged on the side surface of the pipe member. The positional deviation can be isotropically suppressed by the N step portions.

[Application Example 5] The pressure sensor according to Application Example 3, wherein the N stepped portions are not overlapped with each other when viewed along the central axis of the pipe member. A first step portion, a second step portion, and a third step portion that are sequentially arranged on a side surface, and when viewed along the central axis, the first step portion, the second step portion, and the central axis; The first angle with the central axis as a vertex is different from the second angle with the central axis as the vertex formed by the second step portion, the third step portion, and the central axis.

  According to this structure, when providing a resin member, it can suppress setting the direction of the pipe member centering on the central axis of a pipe member accidentally.

[Application Example 6] The pressure sensor according to any one of Application Examples 1 to 5, wherein the stepped portion is a protrusion protruding toward the outside of the pipe member.

  According to this configuration, since the stepped portion does not protrude inside the pipe member, the operability inside the pipe member can be improved.

[Application Example 7] The pressure sensor according to any one of Application Examples 1 to 6, wherein the resin member includes a connector, and the pressure sensor further includes a terminal fixed to the connector; A connection line that connects the terminal and the pressure detection unit, and a position that does not overlap a line segment that connects the terminal and the central axis when the pipe member is viewed along the central axis of the pipe member A pressure sensor in which the step portion is disposed.

  According to this structure, it can prevent that a level | step-difference part contacts a terminal.

[Application Example 8] The pressure sensor according to any one of Application Examples 1 to 7, wherein at least a part of the stepped portion is covered with the resin member.

  According to this configuration, since the resin member covers at least a part of the stepped portion, the positional deviation of the resin member fixed to the pipe member can be suppressed.

[Application Example 9] The pressure sensor according to any one of Application Examples 1 to 8, wherein the step portion is disposed closer to the resin member than the pressure detection unit.

  According to this configuration, it is easy to provide the resin member with high accuracy.

Application Example 10 A pressure sensor unit for an engine, having a spark plug, a side surface having a stepped portion, and a pipe member that houses the spark plug when mounted on the engine; A pressure detection unit provided at one end and sandwiched between the spark plug seat and the spark plug in the engine when mounted on the engine; and a resin member fixed to the pipe member; A pressure sensor unit.

[Application Example 11] A method of manufacturing a pressure sensor for an engine, comprising: a step of forming a step portion on a side surface of a pipe member that houses a spark plug when mounted on the engine; and a first molding die A step of fitting the stepped portion into the stepped receiving portion formed, and a step of forming a cavity having a predetermined shape into which a part of the pipe member is inserted by combining a plurality of forming dies including the first forming die, A step of forming a resin member fixed to the pipe member by filling the cavity with a molten resin, and an end of the pipe member when the ignition plug of the engine is attached to the engine when attached to the engine. And a step of fixing a pressure detector sandwiched between the mounting seat and the spark plug.

  According to this manufacturing method, since the shift of the relative position between the first mold and the pipe member is suppressed by the step portion and the step receiving portion, the resin member can be provided with high accuracy.

[Application Example 12] The manufacturing method according to Application Example 11, wherein the plurality of molds further include a second mold that contacts the pipe member in a state where the cavities are formed to form the cavities. The step of performing includes a step of pressing the step portion of the pipe member against the step receiving portion by bringing the second mold into contact with the pipe member.

  According to this manufacturing method, since the step portion of the pipe member is pressed against the step receiving portion by forming the cavity, the displacement of the pipe member in the cavity can be suppressed. As a result, the resin member can be provided with high accuracy.

[Application Example 13] In the manufacturing method according to Application Example 11 or Application Example 12, the step of forming the step portion includes a step of forming N (N is an integer of 3 or more) step portions, The first mold has N step receiving portions, and the step of fitting the step portions includes a step of fitting the N step portions to the N step receiving portions, respectively.

  According to this manufacturing method, since the relative position between the first mold and the pipe member is determined by a combination of three or more step portions and step receiving portions, the resin member can be provided with high accuracy.

[Application Example 14] The manufacturing method according to Application Example 13, wherein the N stepped portions are not overlapped with each other when viewed along the central axis of the pipe member. When arranged along the side surface and viewed along the central axis, an angle with the central axis formed by two adjacent stepped portions and the central axis is an angle for each of the N stepped portions. Manufacturing method set to the same.

  According to this manufacturing method, when viewed along the central axis of the pipe member, the N step portions are isotropically arranged on the side surface of the pipe member. The relative positional deviation between the two can be suppressed isotropically.

[Application Example 15] The manufacturing method according to Application Example 13, wherein the N stepped portions are not overlapped with each other when viewed along the central axis of the pipe member. A first step portion, a second step portion, and a third step portion that are sequentially arranged on a side surface, and when viewed along the central axis, the first step portion, the second step portion, and the central axis; A manufacturing method in which a first angle formed by the central axis formed by the first step is different from a second angle formed by the central step formed by the second stepped portion, the third stepped portion, and the central axis.

  According to this manufacturing method, it is possible to prevent the pipe member from being attached to the first molding die in a state where the direction of the pipe member around the central axis of the pipe member is wrong.

[Application Example 16] The manufacturing method according to any one of Application Example 11 to Application Example 15, wherein the stepped portion is a protrusion protruding toward the outside of the pipe member, and the step receiving portion is The manufacturing method which is a recessed part into which a protrusion fits.

  According to this manufacturing method, since the stepped portion does not protrude inside the pipe member, the operability inside the pipe member can be improved.

[Application Example 17] The manufacturing method according to any one of Application Example 11 to Application Example 16, wherein the cavity includes a connector cavity for forming a connector, and the step of forming the stepped portion is performed on the pipe member. The manufacturing method includes a step of forming the stepped portion at a position that does not overlap a line segment connecting the position of the terminal in the connector and the central axis when the pipe member is viewed along the central axis. .

  According to this manufacturing method, it can prevent that a level | step-difference part contacts a terminal.

[Application Example 18] The manufacturing method according to any one of Application Example 11 to Application Example 17, wherein the step of molding the resin member includes a step of covering at least a part of the stepped portion with the resin member. Method.

  According to this manufacturing method, since the resin member covers at least a part of the stepped portion, it is possible to suppress the displacement of the resin member fixed to the pipe member.

Application Example 19 In the manufacturing method according to any one of Application Example 11 to Application Example 18, in the step of forming the stepped portion, the resin member is disposed more than the position where the pressure detection unit is to be disposed. The manufacturing method including the process of forming the said level | step-difference part in the position close | similar to the position which should be done.

  According to this manufacturing method, since the shift of the relative position between the portion close to the resin member of the pipe member and the first mold can be appropriately suppressed, it is easy to provide the resin member with high accuracy. is there.

  The present invention can be realized in various forms. For example, a pressure sensor, a pressure sensor manufacturing method, a pressure sensor unit having a pressure sensor and a spark plug, and an internal combustion engine equipped with the pressure sensor unit Or the like.

Next, embodiments of the present invention will be described in the following order based on examples.
A. First embodiment:
B. Second embodiment:
C. Third embodiment:
D. Variation:

A. First embodiment:
A1. Constitution:
FIG. 1 is a longitudinal sectional view showing a pressure sensor 1 for an engine as an embodiment of the present invention. The pressure sensor 1 includes a pipe 4, a sensor unit 2 fixed to one end of the pipe 4, and an annular cap 5 fixed to the other end of the pipe 4. The annular cap 5 includes a connector 5d protruding in a direction perpendicular to the central axis CA of the pipe 4, and a terminal fitting 10 is fixed inside the connector 5d. The terminal fitting 10 and the sensor unit 2 are connected by an output line 3.

  Hereinafter, a direction from the annular cap 5 toward the sensor unit 2 along the central axis CA is referred to as a downward direction DD, a direction opposite to the downward direction DD is referred to as an upward direction UD, and a direction in which the connector 5d protrudes (central axis CA). The direction perpendicular to the front direction FD is called a front direction FD, and the direction opposite to the front direction FD is called a rear direction BD.

  FIG. 2 is an enlarged cross-sectional view of the sensor unit 2 and the annular cap 5. The sensor unit 2 is a cup-shaped unit having a through hole 2a at the center. The sensor unit 2 is arranged around a metal inner cup 2b arranged on the inner side, a metal outer cup 2c arranged on the outer side, and a through hole 2a in a space between the cups 2b and 2c. Pressure detection member 2d. In the present embodiment, the shape of the pressure detection member 2d is an annular shape surrounding the through hole 2a. The pressure detection member 2d is a member that converts a force into an electric signal. In this embodiment, a piezoelectric element is used as the pressure detection member 2d. The core 3a of the output line 3 is connected to the pressure detection member 2d. The space between the cups 2b and 2c is further filled with a filler 8 such as rubber. The filler 8 is hardened in a state where the pressure detection member 2d is enclosed.

  The pipe 4 is obtained by processing a conductive cylindrical metal tube. As shown in FIGS. 1 and 2, a flange 4 a is provided at the upper end of the pipe 4. A narrowed portion 4b whose diameter gradually decreases toward the sensor portion 2 is formed at a position slightly lower than the flange 4a. Hereinafter, a portion of the pipe 4 in the upward direction UD with respect to the narrowed portion 4b is referred to as a pipe upper portion 4j. Further, a portion of the pipe 4 in the lower direction DD than the throttle portion 4b is referred to as a pipe lower portion 4k. The sensor unit 2 is welded to the lower end of the pipe 4. The sensor unit 2 is fixed in a state where the inner cup 2 b is inserted inside the pipe 4.

  FIG. 3 is a schematic view showing the pressure sensor 1 attached to the engine. In the figure, the cylinder head 6 of the engine is shown. The cylinder head 6 is provided with a plug hole 7 for mounting the spark plug 15. The bottom of the plug hole 7 is a seat 7a for mounting an ignition plug (hereinafter also referred to as “plug seat 7a”). The plug seat 7 a is provided with a screw hole 6 a that communicates with the combustion chamber 9. The pressure sensor 1 is inserted into the plug hole 7, and the sensor unit 2 is disposed on the plug seat 7a. A spark plug 15 is accommodated in the pipe 4 of the pressure sensor 1. The spark plug 15 has a seal portion 15b and a mounting screw portion 15a extending from the seal portion 15b. The outer diameter of the seal portion 15b is larger than the outer diameter of the mounting screw portion 15a. A mounting screw portion 15 a is inserted into the through hole 2 a of the sensor portion 2. The attachment screw portion 15 a is screwed into the screw hole 6 a of the cylinder head 6. As a result, the sensor part 2 (particularly the pressure detection member 2d) is sandwiched between the seal part 15b of the spark plug 15 and the plug seat 7a like a washer.

  The pressure detection member 2d outputs a signal according to the tightening force between the seal portion 15b and the plug seat 7a. When the spark plug 15 receives a pressure change in the combustion chamber 9, the tightening force changes. As the tightening force changes, the output signal from the pressure detection member 2d also changes. As a result, the pressure in the combustion chamber 9 can be specified according to the output signal from the pressure detection member 2d.

  FIG. 4 is a perspective view of the upper part of the pressure sensor 1 showing a state where the annular cap 5 is divided at the center. As illustrated, a noise shielding plate 4c made of a conductive metal plate is welded to the upper surface of the flange 4a. The noise shielding plate 4 c is a ring-shaped flat plate and is configured to extend the flange 4 a toward the outside of the pipe 4. In particular, the noise shielding plate 4 c extends to the upper part of the terminal fitting 10, thereby suppressing the influence of electromagnetic noise on the terminal fitting 10. As a source of such electromagnetic noise, for example, there is an ignition coil 16 (FIG. 3) disposed on the upper portion of the annular cap 5. The whole of the pipe 4 and the noise shielding plate 4c corresponds to a “pipe member” in the claims.

  The annular cap 5 is a synthetic resin molded product provided at the end of the pipe 4 in the upward direction UD. The annular cap 5 is formed by insert molding so as to include the end of the pipe 4 in the upward direction UD, the noise shielding plate 4c, and the intermediate portion of the terminal fitting 10 disposed below the noise shielding plate 4c. ing. In the embodiment shown in FIG. 4, the lower end of the terminal fitting 10 is covered with rubber 12.

  As shown in FIG. 2, the annular cap 5 is provided on the upper side of the first portion 5a surrounding the throttle portion 4b of the pipe 4, the second portion 5b surrounding the noise shielding plate 4c, and the second portion 5b. It has the 3rd part 5c and the cylindrical connector 5d which protrudes in the front direction FD from the 2nd part 5b. A gap is provided between the first portion 5 a and the pipe 4. The shape of the third portion 5 c is a cylindrical shape centered on the central axis CA of the pipe 4. The connector 5d surrounds the periphery of the tip portion (pin 10a) of the terminal fitting 10.

  As shown in FIG. 4, a curved portion 4 h that bulges upward in the upward direction UD is formed in a portion 4 d of the noise shielding plate 4 c in the forward direction FD. As a result, the gap between the terminal fitting 10 and the noise shielding plate 4c (curved portion 4h) is suppressed from becoming excessively narrow. And it is suppressed that the flow of the molten resin between the terminal metal fitting 10 and the noise shielding board 4c stagnates.

  A seal ring 13 is attached around the first portion 5a. As shown in FIG. 3, the seal ring 13 seals between the cylinder head 6 and the annular cap 5 in a state where the pressure sensor 1 is mounted on the engine. Further, the protrusion 5e provided on the connector 5d engages with the engaging portion 14a of the other connector 14 inserted into the connector 5d, thereby suppressing the connector 14 from being detached from the connector 5d. As shown in FIGS. 1 and 3, an air vent hole 4 i is provided on the rear direction BD side of the pipe 4.

  FIG. 5 is a cross-sectional view taken along line XX in FIG. This cross-sectional view shows a cross section perpendicular to the central axis CA. An output line cover 11 for protecting the output line 3 is fixed to the front direction FD side of the outer peripheral surface 4 g of the pipe 4. The output line cover 11 is a cover extending along the central axis CA, and includes a main body 11a having a shape obtained by dividing a pipe into two in the axial direction, and mounting plates 11b provided on both sides of the main body 11a. . The concave surface 11 c of the main body 11 a faces the outer peripheral surface 4 g of the pipe 4. The mounting plate 11b is fixed to the outer peripheral surface 4g by spot welding. Spots Wa, Wb, Wc, Wd, and We shown in FIG. 1 indicate welding positions.

  A space S is formed between the concave surface 11c and the outer peripheral surface 4g. The space S extends in parallel with the central axis CA from the sensor unit 2 to the vicinity of the connector 5d (FIG. 1). The output line 3 passes through this space S. The space S is filled with the filler 8. The output line 3 is fixed in the space S by the filler 8. The main body 11a is provided with a plurality of filling ports 11d. The filler 8 is filled from the filling port 11d.

  In this embodiment, when the pressure sensor 1 is used by being mounted on an engine, an ignition coil 16 is installed on the third portion 5c as shown in FIG. A plug cap 16 a is provided below the ignition coil 16. The plug cap 16 a passes through the pipe 4 and fits into a terminal 15 c at the top of the spark plug 15. The ignition coil 16 and the ignition plug 15 (terminal 15c) are electrically connected by the plug cap 16a. The connector 5d is connected to a signal line connector 14 connected to an engine control device (not shown). As a result, the control device and the sensor unit 2 are electrically connected. During the operation of the engine, the control device uses the signal from the sensor unit 2 to identify the pressure inside the combustion chamber 9. Then, the control device controls the engine according to the specified pressure so that the combustion state in the combustion chamber 9 becomes an appropriate state.

A2. Production method:
FIG. 6 is a flowchart showing the procedure of the manufacturing method of the pressure sensor 1. The first step S100 is processing of the pipe 4. FIG. 7 is a perspective view showing the processed pipe 4. In this embodiment, the cylindrical metal tube is deformed in a plurality of stages using a plurality of types of molding molds (not shown). By this deformation, the narrowed portion 4b, the pipe upper portion 4j, the pipe lower portion 4k, and the flange 4a are formed. The noise shielding plate 4c is welded to the flange 4a. In the present embodiment, three protrusions are formed on the side surface of the pipe 4 (in the present embodiment, the narrowed portion 4b). In FIG. 7, two protrusions P1 and P2 are shown, and the third protrusion is hidden behind the pipe lower part 4k. These protrusions protrude toward the outside of the pipe 4. In the present embodiment, projections are provided between both ends of the pipe 4.

  FIG. 8 is a perspective view of the pressure sensor 1 as viewed along the downward direction DD (center axis CA). In the figure, three protrusions P1, P2, and P3 are shown. When viewed along the central axis CA, the three protrusions P1, P2, and P3 are arranged at equal intervals on the side surface of the pipe 4 (the restricting portion 4b in this embodiment). That is, when viewed along the central axis CA, the angles T1, T2, and T3 between the protrusions having the central axis CA as a vertex are the same. Here, the first angle T1 indicates an angle formed by the first protrusion P1, the second protrusion P2, and the central axis CA, and the second angle T2 indicates that the second protrusion P2, the third protrusion P3, and the central axis CA are The third angle T3 indicates an angle formed by the third protrusion P3, the first protrusion P1, and the central axis CA. The reason why the protrusions P1, P2, and P3 are isotropically arranged will be described later.

  Each of the three protrusions P1, P2, and P3 is disposed at a position that does not overlap with a line segment that connects the terminal fitting 10 and the central axis CA. A hatched area SA in the figure indicates an area through which such a line segment can pass. When viewed along the central axis CA, no protrusion is disposed at a position overlapping the area SA. As a result, the protrusion can be prevented from coming into contact with the terminal fitting 10. However, a part of the protrusion may be disposed at a position overlapping the area SA.

  The next step S110 in FIG. 6 is the attachment of the pipe 4 to the mold. FIG. 9 is a schematic view showing how the pipe 4 is mounted on the first molding die DA. FIG. 9 shows a first molding die DA, a connector die DC, and a pipe 4. In the figure, four directions UD, DD, FD, and BD are shown. These directions indicate the directions of the pipes 4 attached to the first molding die DA.

  A first recess DAR1 is formed on the upper surface UD of the first mold DA. A second recess DAR2 is formed in the front direction FD of the surface SU with respect to the first recess DAR1. A through hole DAH extending in the downward direction DD is formed in the central portion of the first recess DAR1.

  FIG. 10 is a cross-sectional view showing the combined first molding die DA, connector die DC, and pipe 4. This sectional view shows a section passing through the central axis CA of the pipe 4 and parallel to the front direction FD. As illustrated, the first molding die DA is formed by combining a plurality of parts. Further, the first molding die DA is formed with a resin flow path RPA communicating with the first recess DAR1. Note that FIG. 10 also shows another molding die arranged around the first molding die DA and the connector die DC.

  In step S110, first, the connector type DC is mounted on the first molding die DA. The connector type DC has a protrusion DCC. When the connector mold DC is attached to the first molding die DA, the protruding portion DCC is disposed inside the second recess DAR2. The second recess DAR2 forms a cavity for the connector 5d (FIG. 1). The protruding portion DCC forms an internal space of the connector 5d. A terminal fitting 10 is attached in advance to the protruding portion DCC. The protruding portion DCC holds the terminal fitting 10 in a state where the terminal fitting 10 is disposed inside the second recess DAR2. Note that one end (pin 10a) of the terminal fitting 10 is inserted into the hole of the protruding portion DCC. The other end 10b of the terminal fitting 10 is inserted into the hole of the first molding die DA. Thereby, it is suppressed that both ends 10a and 10b of the terminal metal fitting 10 are covered with resin.

  Next, the pipe 4 is attached to the first mold DA. As shown in FIG. 9, the first recess DAR1 has three recesses R1, R2, and R3. The three recesses R1, R2, R3 are arranged so as to surround the through hole DAH. The shape and arrangement of the three recesses R1, R2, and R3 are configured such that the three protrusions P1, P2, and P3 of the pipe 4 fit into the three recesses R1, R2, and R3, respectively.

  The pipe lower part 4k is inserted into the through hole DAH. The three protrusions P1, P2, and P3 are fitted into the three recesses R1, R2, and R3, respectively. As a result, the first molding die DA holds the pipe upper portion 4j in a state where it is disposed inside the first recess DAR1.

  As described above, the three protrusions P1, P2, and P3 are arranged isotropically. That is, the three recesses R1, R2, and R3 are arranged at equal intervals so as to surround the periphery of the pipe 4 when viewed along the central axis CA. As a result, the relative positional deviation between the first mold DA and the pipe 4 can be suppressed isotropically.

  The next step S120 in FIG. 6 is a process of combining the molds. FIG. 11 is a perspective view showing a second molding die DB combined with the first molding die DA (FIGS. 9 and 10). In the figure, four directions UD, DD, FD, and BD are shown. These directions indicate the direction of the pipe 4 in a state where the second mold DB, the pipe 4 and the first mold DA are combined.

  A first recess DBR1 is formed on the surface SD in the downward direction DD of the second mold DB. A second recess DBR2 is formed in the front direction FD with respect to the first recess DBR1 of the surface SD. A protruding portion DBP1 that protrudes in the downward direction DD is provided at the center of the first recess DBR1.

  FIG. 12 is a cross-sectional view showing the combined first molding die DA, connector die DC, pipe 4 and second molding die DB. This sectional view shows a sectional view similar to FIG. As shown in the drawing, a resin flow path RPB communicating with the resin flow path RPA is formed in the second mold DB.

  When the second mold DB is combined with the first mold DA, a cavity CB surrounded by the recesses DAR1, DAR2, DBR1, DBR2 is formed. The first recess DAR1 and the first recess DBR1 form a cavity for forming the first portion 5a, the second portion 5b, and the third portion 5c of the annular cap 5 (FIG. 1). The second recess DAR2 and the second recess DBR2 form a cavity for forming the connector 5d (corresponding to “connector cavity” in the claims). The pipe upper portion 4j is disposed inside the cavity CB.

  The ring-shaped corner DBP1C (FIG. 11) of the protrusion DBP1 of the second mold DB is in contact with the flange 4a (FIG. 2) over the entire circumference. The pipe 4 is pushed downward DD by the protrusion DBP1. Accordingly, the three protrusions P1, P2, and P3 are pressed toward the three recesses R1, R2, and R3, respectively. As a result, the displacement of the pipe 4 in the cavity CB can be suppressed. Note that the second mold DB is not limited to the pipe 4 (flange 4a), but comes into contact with other members (for example, the noise shielding plate 4c) fixed to the pipe 4 to thereby form the projections P1 of the three pipes 4, P2 and P3 may be pressed toward the three recesses R1, R2, and R3, respectively. Further, only a part of the plurality of protrusions of the pipe 4 may be pressed toward the recess.

  In addition, only the part which should be covered with resin among the pipe 4 and the noise shielding board 4c has appeared in the cavity CB. Other parts are hidden by the mold.

  The next step S130 in FIG. 6 is forming the annular cap 5. FIG. 13 is a cross-sectional view showing molding of the annular cap 5. FIG. 13 shows a part of a sectional view similar to FIG. In this step S130, the molten resin is supplied to the resin flow path RPB. The molten resin flows into the cavity CB through the resin flow path RPA. The cavity CB is filled with molten resin. In FIG. 13, the filled molten resin is indicated by hatching. By this filling, an annular cap 5 fixed to the pipe 4 is formed as shown in FIGS. Thus, the annular cap 5 is fixed to the pipe 4 by insert molding. Note that the filling temperature and the filling pressure may be experimentally determined in advance.

FIG. 14 is an explanatory view showing a comparative example of filling a molten resin. In this comparative example, a pipe 4X is used. The only difference from the pipe 4 of the first embodiment is that the protrusions P1, P2, and P3 are omitted. Since the pipe 4X has no projection, the position of the pipe 4X is easily shifted. In FIG. 14, the position of the pipe 4X in the cavity CB is shifted in the backward direction BD. In this case, a gap G1 is generated between the protrusion DBP1 and the pipe upper portion 4j. As a result, the molten resin can flow into the pipe upper portion 4j through the gap G1. However, in this embodiment, as described above, the displacement of the pipe 4 in the cavity CB is suppressed by the protrusions P1, P2, and P3 and the recesses R1, R2, and R3. Therefore, it is possible to suppress the occurrence of an unintended gap between the mold and the pipe 4. As a result, it is possible to suppress the molten resin from flowing into an unintended region.

  Further, if the position of the pipe 4 is deviated in the cavity CB, the molten resin may flow in an unintended direction in the cavity CB. Such unintended flow may reduce the accuracy of molding. However, in this embodiment, since the displacement of the pipe 4 is suppressed, it is possible to improve the accuracy of forming the annular cap 5 (FIG. 2), and consequently improve the accuracy of forming the connector 5d. it can. In the present embodiment, the terminal fitting 10 is fixed to the connector 5d by insert molding. In this case, the positional deviation between the connector 5d and the terminal fitting 10 can be suppressed by improving the molding accuracy of the connector 5d. As a result, it is possible to prevent the connector 14 (FIG. 3) from being attached to the connector 5d due to such positional deviation.

  After the filled resin is hardened, the combined mold is disassembled, and the joined body of the pipe 4 and the annular cap 5 is removed from the mold. As described above, in this embodiment, since the molten resin is suppressed from flowing in an unintended region, it is possible to suppress the formation of excessive burrs.

  The next step S140 in FIG. 6 is fixing the sensor unit 2 (FIG. 1). In the present embodiment, the sensor unit 2 is fixed to the end portion of the pipe 4 in the lower direction DD by welding. Next, the other end of the output line 3 having one end connected to the pressure detection member 2d is connected to the terminal fitting 10. Next, the output line cover 11 is fixed to the pipe 4. And the pressure sensor 1 is completed.

  As described above, in this embodiment, the projections P1, P2, and P3 provided on the pipe 4 are used for positioning the pipe 4 with respect to the first molding die DA, so that the annular cap 5 can be provided with high accuracy. .

  As shown in FIG. 1, the protrusion (for example, the first protrusion P1) is disposed at a position closer to the annular cap 5 than the pressure detection member 2d. As a result, since the shift of the relative position between the part near the annular cap 5 in the pipe 4 and the first molding die DA (FIG. 12) can be appropriately suppressed, the annular cap 5 can be provided with high accuracy. it can. Note that the shortest distance may be used for the distance comparison. For example, the shortest distance D1 (FIG. 1) between the first protrusion P1 and the annular cap 5 is preferably shorter than the shortest distance D2 between the first protrusion P1 and the pressure detection member 2d. The same applies to the other protrusions P2 and P3. Note that at least a part of the protrusions may be disposed at a position closer to the pressure detection member 2 d than the annular cap 5.

B. Second embodiment:
FIG. 15 is an explanatory view showing a pressure sensor 1A of the second embodiment. The only difference from the pressure sensor 1 shown in FIG. 8 is that the position of the second protrusion P2 is different. Other configurations and manufacturing methods are the same as those in the first embodiment.

  Also in the second embodiment, the second protrusion P2 is provided on the restricting portion 4b. However, the second protrusion P2 is arranged at a position closer to the first protrusion P1 than the third protrusion P3. That is, the first angle T1 is smaller than the second angle T2. Although not shown, as the first mold, the shape and arrangement of the three recesses R1, R2, and R3 in the first mold DA shown in FIG. 9 are the three protrusions P1 of the pressure sensor 1A. , P2 and P3 are used to obtain a mold obtained by modification. As a result, it is possible to prevent the pipe 4 from being attached to the first molding die in a state where the direction of the pipe 4 around the central axis CA is wrong. For example, even if an attempt is made to fit the first projection P1 into a recess for projections other than the first projection P1, other projections do not fit into the recess, so that the pipe 4 can be attached to the first mold. Can not.

  Also in this embodiment, when viewed along the central axis CA, each of the three protrusions P1, P2, and P3 does not overlap a line segment (area SA) connecting the terminal fitting 10 and the central axis CA. Placed in position.

C. Third embodiment:
FIG. 16 is an explanatory view showing a pressure sensor 1B of the third embodiment. The only difference from the pressure sensor 1 shown in FIG. 4 is that the first portion 5aB of the annular cap 5BB has a portion (concave portion) that closely contacts and covers the protrusions P1, P2, and P3 of the pipe 4. FIG. 16 shows a first recess 5R1 that covers the first projection P1 and a third recess 5R3 that covers the third projection P3 (the second recess covering the second projection P2 is the second recess 5b). Hiding behind). Each concave portion covers a part of the upward direction UD of the protrusion. Other configurations and manufacturing methods are the same as those in the first embodiment.

  FIG. 17 is a cross-sectional view showing a first mold DAB used for manufacturing the pressure sensor 1B. A difference from the first mold DA shown in FIG. 13 is that a part of each of the three protrusions P1, P2, and P3 appears in the cavity CBB (the two protrusions P2 and P3 are not shown). . In this embodiment, a part of the upward direction UD of the protrusion appears in the cavity CBB. By using such a first molding die DAB, the annular cap 5BB (first portion 5aB) is formed with a recess that covers a part of the protrusions P1, P2, P3 in the upward direction UD. As a result, positional deviation of the annular cap 5BB fixed to the pipe 4 can be suppressed. An annular cap that covers a part of the protrusion can also be applied to the pressure sensor 1A shown in FIG.

D. Variation:
In addition, elements other than the elements claimed in the independent claims among the constituent elements in each of the above embodiments are additional elements and can be omitted as appropriate. The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

Modification 1:
In each of the above-described embodiments, a protrusion protruding toward the outside of the pipe 4 (for example, the first protrusion P1 in FIG. 7) is employed as the stepped portion provided in the pipe 4. As a result, since the stepped portion does not protrude inside the pipe 4, the operability inside the pipe can be improved. For example, the spark plug 15 can be easily accommodated in the pipe 4. Further, when the spark plug 15 is tightened with a plug wrench, the stepped portion does not obstruct the rotation of the plug wrench.

  Note that the stepped portion provided in the pipe 4 is not limited to the protrusion, and may be a recessed portion that is recessed toward the inside of the pipe 4. Also in this case, since the recess can be used for positioning the pipe, the resin member can be provided with high accuracy. As the step receiving portion provided in the mold, a protrusion that fits into the concave portion of the pipe may be employed. Further, the step portion may include both the protrusion and the recess. In general, the step portion may include at least one of a protrusion and a recess. Various shapes can be adopted as the shape of the stepped portion. For example, a protrusion protruding in a direction perpendicular to the central axis CA may be adopted as the stepped portion. In any case, the shape of the step receiving portion may be any shape that allows the step portion to be fitted. An arbitrary direction can be adopted as the direction in which the step portion is fitted into the step receiving portion. Note that the direction in which the stepped portion fits into the step receiving portion means the relative moving direction of the stepped portion when the stepped portion is fitted into the step receiving portion by moving the stepped portion relative to the step receiving portion. is doing. For example, in the embodiment shown in FIG. 9, this direction is a downward direction DD parallel to the central axis CA of the pipe 4. That is, each of the three concave portions R1, R2, and R3 faces the upward direction UD so as to receive the protrusions P1, P2, and P3 moving in the downward direction DD.

  Also, in the case of adopting a recess as the step provided in the pipe, the resin member may cover and closely cover a part of the recess (step) in the pipe as in the embodiments shown in FIGS. preferable. In this case, the resin member has a protrusion that enters the recess of the pipe. Also in this case, the positional deviation of the resin member fixed to the pipe can be suppressed.

Modification 2:
In each of the above-described embodiments, the total number of stepped portions provided on the pipe is not limited to 3, and any number can be adopted. For example, 1 or 2 can be adopted. However, the total number of stepped portions is preferably 3 or more. If three or more step portions are used, three degrees of freedom regarding the arrangement of the pipes are eliminated. That is, the relative position between the mold and the pipe is determined by three or more step portions. As a result, it is easy to improve the positioning accuracy of the pipe.

Modification 3:
In each of the above-described embodiments, the position of the pipe extending direction (in each of the above-described embodiments, the direction parallel to the central axis CA) may be different from at least a part of the plurality of step portions. For example, in the pipe 4 shown in FIG. 7, the first protrusion P1 may be formed at the center portion of the pipe lower part 4k. However, as in the above-described embodiments, it is preferable that the positions in the direction in which the pipe extends are the same for all the stepped portions. If it carries out like this, the position shift of the pipe in the vicinity of a level difference part can be controlled effectively.

Modification 4:
In the above-described embodiments, various shapes extending in a predetermined direction can be adopted as the shape of the pipe. For example, the cross-sectional shape of the pipe may be a polygon. Further, the cross-sectional shape of the pipe may change according to the position in the direction in which the pipe extends. Moreover, you may employ | adopt the straight pipe whose cross-sectional shape does not change.

  In any case, as the pipe, a pipe including a rotationally symmetric portion around the central axis can be employed. Here, as the rotationally symmetric portion, for example, a cylinder, a triangular prism, a quadrangular prism, or the like can be adopted. Further, the cross-sectional shape of the pipe may change according to the position along the central axis. Further, “the central axis of the pipe member” means the central axis of a pipe (particularly a rotationally symmetric part) included in the pipe member.

  Further, it is preferable to arrange N (N is an integer of 3 or more) stepped portions with such a central axis as a reference. For example, it is preferable to arrange N step portions as in the embodiment shown in FIG. That is, the N step portions are arranged side by side on the side surface of the pipe so as not to overlap each other when viewed along the central axis. And when it sees along a central axis, the angle which makes the center axis | shaft which two adjacent level | step-difference parts and a central axis make a vertex is set equally about each of N level | step-difference parts.

  Moreover, it is also preferable to arrange N stepped portions as in the embodiment shown in FIG. That is, the N stepped portions include the first stepped portion, the second stepped portion, and the third stepped portion that are sequentially arranged on the side surface of the pipe so as not to overlap each other when viewed along the central axis. And when it sees along a central axis, the 1st angle which makes the central axis which a 1st level difference part, a 2nd level difference part, and a central axis make apex are the 2nd level difference part, the 3rd level difference part, and a central axis This is different from the second angle with the central axis formed by.

  In any case, the N step portions may be provided in a rotationally symmetric portion of the pipe. Further, some or all of the stepped portions may be provided in a portion different from the rotationally symmetric portion.

Modification 5:
In each of the embodiments described above, the resin member is not limited to the annular cap that covers the entire circumference of one end of the pipe, and various members can be employed. For example, the resin member may be a connector formed in the middle of a pipe. Further, the resin member may be a member that does not have a connector. Further, the position where the resin member is formed is not limited to the end of the pipe, but may be another position.

Modification 6:
In each of the above-described embodiments, the pressure sensor manufacturing procedure is not limited to the procedure shown in FIG. 6, and other various procedures can be adopted. For example, the annular cap 5 may be formed after the sensor unit 2 is fixed to the pipe 4.

Modification 7:
In each of the above-described embodiments, the configuration of the pressure sensor is not limited to the configurations illustrated in FIGS. 1 to 5, 7 to 8, 15, and 16, and various configurations can be employed. For example, the noise shielding plate 4c (FIG. 2) may be omitted. In addition, a double-structured pipe having an inner wall and an outer wall may be used, and a connection line that connects the terminal fitting 10 and the pressure detection member 2d may be disposed between the inner wall and the outer wall. Further, the shape of the pressure detection member 2d (FIG. 3) is not limited to an annular shape, and any shape sandwiched between the plug seat 7a and the spark plug 15 can be employed.

It is a longitudinal section showing pressure sensor 1 for engines as one example of the present invention. 4 is an enlarged cross-sectional view of the sensor unit 2 and the annular cap 5. FIG. It is the schematic which shows the pressure sensor 1 with which the engine was mounted | worn. It is a perspective view of the upper part of the pressure sensor 1 which shows the state which divided | segmented the annular cap 5 in the center. It is XX sectional drawing in FIG. 4 is a flowchart showing a procedure of a manufacturing method of the pressure sensor 1. It is a perspective view which shows the processed pipe 4. FIG. It is the perspective view which looked at the pressure sensor 1 along the downward direction DD (center axis CA). It is the schematic which shows a mode that the pipe 4 is mounted | worn with 1st shaping | molding die DA. It is sectional drawing which shows the 1st shaping | molding die DA, the connector type DC, and the pipe 4 which were combined. It is a perspective view which shows 2nd shaping | molding die DB. It is sectional drawing which shows 1st shaping | molding die DA, the connector type | mold DC, the pipe 4, and 2nd shaping | molding die DB which were combined. FIG. 5 is a cross-sectional view showing molding of an annular cap 5. It is explanatory drawing which shows the comparative example of filling of molten resin. It is explanatory drawing which shows the pressure sensor 1A of 2nd Example. It is explanatory drawing which shows the pressure sensor 1B of 3rd Example. It is sectional drawing which shows the 1st shaping | molding die DAB utilized for manufacture of the pressure sensor 1B.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1A, 1B ... Pressure sensor 2 ... Sensor part 2a ... Through-hole 2b ... Inner cup 2c ... Outer cup 2d ... Pressure detection member 3 ... Output line 3a ... Core wire 4 ... Pipe 4a ... Flange 4b ... Restriction part 4c ... Noise shielding Plate 4d ... part 4g ... outer peripheral surface 4h ... curved part 4i ... hole 4j ... pipe upper part 4k ... pipe lower part 5 ... annular cap 5a ... first part 5b ... second part 5c ... third part 5d ... connector 5e ... projection 5R1 ... 1st recessed part 5BB ... annular cap 5R3 ... 3rd recessed part 5aB ... 1st part 6 ... cylinder head 6a ... screw hole 7 ... plug hole 7a ... plug seat 8 ... filler 9 ... combustion chamber 10 ... terminal metal fitting 10a ... pin 11 ... Output line cover 11a ... Main body 11b ... Mounting plate 11c ... Concave surface 11d ... Filling port 12 ... Rubber 13 ... Seal ring 14 ... Connector 14a ... Engagement part 15 ... Spark plug DESCRIPTION OF SYMBOLS 15a ... Installation screw part 15b ... Seal part 15c ... Terminal 16 ... Ignition coil 16a ... Plug cap S ... Space DAR1 ... 1st recessed part DAR2 ... 2nd recessed part DBR1 ... 1st recessed part DBR2 ... 2nd recessed part DBP1 ... Projection part DBP1C ... Corner P1, P2, P3 ... 1st protrusion R1, R2, R3 ... Recess G1 ... Clearance CA ... Center axis SA ... Area DA ... 1st shaping | molding die DB ... 2nd shaping | molding die CB ... Cavity DC ... Connector type DAB ... 1st shaping | molding Type CBB ... Cavity DCC ... Protrusion DAH ... Through hole RPA ... Resin channel RPB ... Resin channel

Claims (19)

A pressure sensor for an engine,
A pipe member having a side surface having a stepped portion and storing a spark plug when mounted on the engine;
A pressure detector provided at one end of the pipe member and sandwiched between the spark plug mounting seat and the spark plug in the engine when mounted on the engine;
A resin member fixed to the pipe member;
A pressure sensor. The pressure sensor according to claim 1,
The resin member is fixed to the pipe member by insert molding.
Pressure sensor. The pressure sensor according to claim 1 or 2,
The pipe member has N steps (N is an integer of 3 or more),
Pressure sensor. The pressure sensor according to claim 3,
The N stepped portions are arranged side by side on the side surface of the pipe member so as not to overlap each other when viewed along the central axis of the pipe member.
When viewed along the central axis, an angle with the central axis formed by two adjacent stepped portions and the central axis is set to be the same for each of the N stepped portions.
Pressure sensor. The pressure sensor according to claim 3,
The N stepped portions are arranged in order on the side surface of the pipe member so as not to overlap each other when viewed along the central axis of the pipe member. Including a stepped portion,
When viewed along the central axis, the first angle with the central axis formed by the first stepped portion, the second stepped portion, and the central axis is the second stepped portion and the third stepped portion. Different from the second angle with the central axis formed by the step portion and the central axis,
Pressure sensor. The pressure sensor according to any one of claims 1 to 5,
The step portion is a protrusion protruding toward the outside of the pipe member.
Pressure sensor. The pressure sensor according to any one of claims 1 to 6,
The resin member includes a connector,
The pressure sensor further includes:
A terminal fixed to the connector;
A connection line connecting the terminal and the pressure detector;
Including
When the pipe member is viewed along the central axis of the pipe member, the stepped portion is disposed at a position that does not overlap a line segment connecting the terminal and the central axis.
Pressure sensor. The pressure sensor according to any one of claims 1 to 7,
At least a part of the stepped portion is covered with the resin member;
Pressure sensor. The pressure sensor according to any one of claims 1 to 8,
The step portion is disposed at a position closer to the resin member than the pressure detection portion,
Pressure sensor. A pressure sensor unit for an engine,
Spark plugs,
A pipe member having a side surface having a stepped portion, and housing the spark plug when mounted on the engine;
A pressure detector provided at one end of the pipe member and sandwiched between the spark plug mounting seat and the spark plug in the engine when mounted on the engine;
A resin member fixed to the pipe member;
A pressure sensor unit. A method of manufacturing a pressure sensor for an engine,
Forming a step on the side surface of the pipe member that houses the spark plug when mounted on the engine;
A step of fitting the stepped portion into a step receiving portion provided in the first mold;
Forming a cavity having a predetermined shape into which a part of the pipe member is inserted by combining a plurality of molds including the first mold;
Molding the resin member fixed to the pipe member by filling the cavity with molten resin;
Fixing one end of the pipe member to a pressure detection unit sandwiched between the seat for mounting the spark plug in the engine and the spark plug when mounted on the engine;
A manufacturing method comprising: It is a manufacturing method of Claim 11, Comprising:
The plurality of molds further include a second mold that contacts the pipe member in a state where the cavity is formed,
The step of forming the cavity includes a step of pressing the step portion of the pipe member against the step receiving portion by bringing the second mold into contact with the pipe member.
Production method. The manufacturing method according to claim 11 or 12,
The step of forming the step portion includes a step of forming N (N is an integer of 3 or more) step portions,
The first mold has N step receiving portions,
The step of fitting the step portion includes a step of fitting the N step portions to the N step receiving portions, respectively.
Production method. It is a manufacturing method of Claim 13, Comprising:
The N stepped portions are arranged side by side on the side surface of the pipe member so as not to overlap each other when viewed along the central axis of the pipe member,
When viewed along the central axis, an angle with the central axis formed by two adjacent stepped portions and the central axis is set to be the same for each of the N stepped portions.
Production method. It is a manufacturing method of Claim 13, Comprising:
The N stepped portions are arranged in order on the side surface of the pipe member so as not to overlap each other when viewed along the central axis of the pipe member. Including a stepped portion,
When viewed along the central axis, the first angle with the central axis formed by the first stepped portion, the second stepped portion, and the central axis is the second stepped portion and the third stepped portion. Different from the second angle with the central axis formed by the step portion and the central axis,
Production method. A manufacturing method according to any one of claims 11 to 15,
The step portion is a protrusion protruding toward the outside of the pipe member,
The step receiving portion is a recess into which the protrusion fits.
Production method. A manufacturing method according to any one of claims 11 to 16, comprising:
The cavity includes a connector cavity for molding a connector;
The step of forming the stepped portion is a position that does not overlap with a line segment connecting the position of the terminal in the connector and the central axis when the pipe member is viewed along the central axis of the pipe member. Including the step of forming the stepped portion.
Production method. A manufacturing method according to any one of claims 11 to 17,
The step of molding the resin member includes a step of covering at least a part of the stepped portion with the resin member.
Production method. The manufacturing method according to any one of claims 11 to 18,
The step of forming the stepped portion includes a step of forming the stepped portion at a position closer to a position where the resin member is to be disposed than a position where the pressure detecting portion is to be disposed.
Production method.

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