JP5636999B2 - Injector - Google Patents

Description

  The present invention relates to an injector that controls the opening / closing operation of a nozzle by controlling the pressure of a back pressure chamber.

  A conventional fuel injection device is configured to inject and supply high-pressure fuel stored in a common rail into a combustion chamber of each cylinder of an internal combustion engine via an injector. The injector includes a nozzle that opens and closes the nozzle hole with a needle and injects fuel when the valve is opened, and pressure control means that controls the opening and closing operation of the nozzle by controlling the pressure acting on the side opposite to the nozzle hole in the needle .

  In some injectors in which pressure control means is constituted by a piezoelectric actuator and a back pressure control mechanism, the piezoelectric actuator is assembled from the nozzle side of the injector body. Specifically, two lead wires for power feeding are previously welded to the terminal of the piezo actuator, the lead wire is first inserted into the storage hole of the injector body, and then the piezo actuator is inserted into the storage hole. The lead wire is pushed by the piezo actuator and advances through the injector body, and the tip of the lead wire is guided to the other end opening of the storage hole.

  However, since the lead wire is long and low in rigidity, the lead wire is easily bent in the storage hole when the lead wire and the actuator are assembled to the injector body, and therefore it is not easy to guide the lead wire to the other end of the storage hole. There was a problem that the workability of assembling the lead wire and the piezo actuator to the injector body was poor.

  Therefore, as shown in FIG. 8, the lead wire 22 is held by the holding member 8 having higher rigidity than the lead wire 22, thereby preventing the lead wire 22 from being bent when the lead wire 22 and the actuator 2 are assembled to the injector body. Therefore, the assembly workability is improved (for example, see Patent Document 1).

Japanese Patent No. 4549558

  However, in the conventional injector, when the lead wire 22 and the terminal 24 are welded, spatter S (metal melted) is generated, and a part of the spatter S is scattered around, and a part of the spatter S is not present in the welded portion. It may adhere stably (see FIG. 8A). Then, as shown in FIG. 8B, when the lead wire 22 is inserted into the insertion space 81 formed in the holding member 8, the spatter S adhering to the welded portion falls off, and the spatter S is 2 There was a risk of short circuiting due to contact with the two terminals 24.

  An object of the present invention is to prevent a short circuit between terminals due to sputtering generated when welding a lead wire and a terminal in an injector that holds the lead wire by a holding member.

In order to achieve the above object, according to the first aspect of the present invention, a nozzle (1) that opens or closes according to the pressure in the back pressure chamber and injects fuel when the valve is opened, and one end to the other end A cylindrical injector body (4) having a storage hole (41) penetrating up to and including a pressure control means (2, 3) stored in the storage hole (41) and controlling the pressure of the back pressure chamber according to an electrical signal And two lead wires (22) for feeding, one end of which is welded to the two terminals (24) of the pressure control means (2, 3), and a rigidity higher than that of the lead wire (22) and each lead A holding member (8) having two insertion spaces (81) into which the wire (22) is inserted and having a partition wall portion (82) separating the two insertion spaces (81) ; 22) with the lead wire (22) and the holding part inserted in the insertion space (81) In the injector configured to insert (8) into the storage hole (41) from one end side thereof and to take out the other end of the lead wire (22) from the other end side of the storage hole (41), two terminals (24 ) Is held by an insulating member (23) made of an insulating material, and is welded to the lead wire (22) at a protruding end (241) which is a portion protruding from the insulating member (23). ) Includes a partition part (233a) located between the two projecting end parts (241) and projecting toward the holding member (8), and the partition part (233a) includes an axis of the insulating member (23). A groove portion (234) extending in a direction perpendicular to the groove portion (234) is formed, the partition wall portion (82) of the holding member (8) enters the groove portion (234), and the partition portion (233a) is inserted into the insertion space (81). It is characterized by being

  According to this, when the lead wire (22) was inserted into the insertion space (81) of the holding member (8), even if the spatter adhered to the welded part dropped, the sputter contacted one terminal. However, since the contact with the other terminal is blocked by the partition portion (233a), it is possible to prevent a short circuit between the terminals (24) due to the dropped spatter.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

It is a fragmentary sectional view of the injector for fuel injection equipment concerning a 1st embodiment of the present invention. It is typical sectional drawing which shows the schematic internal structure of the injector of FIG. It is an expanded sectional view of the A section of FIG. It is sectional drawing which follows the BB line of FIG. It is sectional drawing which shows the modification of 1st Embodiment. It is sectional drawing which shows the principal part of the injector which concerns on 2nd Embodiment of this invention. It is sectional drawing of the insulation member and terminal along a CC line of FIG. It is sectional drawing of the principal part of the conventional injector.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
A first embodiment of the present invention will be described. FIG. 1 is a partial sectional view of an injector for a fuel injection device according to a first embodiment of the present invention, and FIG. 2 is a schematic sectional view showing a schematic internal configuration of the injector of FIG.

  First, the basic configuration and operation of the injector will be described with reference to FIGS. 1 and 2. The injector is for injecting high-pressure fuel stored in a common rail (not shown) into a cylinder of a diesel internal combustion engine (not shown). A piezoelectric actuator 2 that expands and contracts, and a back pressure control mechanism 3 that is driven by the piezoelectric actuator 2 to control the back pressure of the nozzle 1 are provided.

  The nozzle 1 includes a nozzle body 12 in which an injection hole 11 is formed, a needle 13 that opens and closes the injection hole 11 in contact with and away from the valve seat of the nozzle body 12, and a spring 14 that urges the needle 13 in a valve closing direction.

  The piezo actuator 2 includes a piezo stack 21 in which a large number of piezoelectric elements are stacked. The piezo stack 21 is connected to a power source (not shown) via two lead wires 22. The lead wire 22 is held by the holding member 8 having higher rigidity than the lead wire 22. Details of the holding member 8 will be described later.

  The valve body 31 of the back pressure control mechanism 3 is driven by a piston 32 that moves following the expansion and contraction of the piezoelectric actuator 2, a disc spring 33 that biases the piston 32 toward the piezoelectric actuator 2, and a piston 32. A spherical valve element 34 is accommodated. Incidentally, in FIG. 2, the valve body 31 is illustrated as one component, but is actually divided into a plurality of parts. The piezo actuator 2 and the back pressure control mechanism 3 constitute pressure control means of the present invention.

  The substantially cylindrical injector body 4 is formed with a storage hole 41 penetrating from one end side to the other end side in the injector axial direction. The piezoelectric actuator 2 and the back pressure control mechanism 3 are stored in the storage hole 41. Has been. Further, the nozzle 1 is held at the end of the injector body 4 by screwing the substantially cylindrical retainer 5 into the injector body 4.

  The nozzle body 12, the injector body 4 and the valve body 31 are formed with a high pressure passage 6 to which high pressure fuel is always supplied from the common rail, and the injector body 4 and the valve body 31 are connected to a fuel tank (not shown). 7 is formed.

  A high pressure chamber 15 is formed between the outer peripheral surface of the needle 13 on the nozzle hole 11 side and the inner peripheral surface of the nozzle body 12. The high pressure chamber 15 communicates with the nozzle hole 11 when the needle 13 is displaced in the valve opening direction. The high pressure chamber 15 is always supplied with high pressure fuel via the high pressure passage 6. A back pressure chamber 16 is formed on the side opposite to the injection hole of the needle 13. In the back pressure chamber 16, the above-described spring 14 is disposed.

  The valve body 31 is formed with a high-pressure seat surface 35 in a path communicating the high-pressure passage 6 in the valve body 31 and the back pressure chamber 16 of the nozzle 1, and the back of the low-pressure passage 7 in the valve body 31 and the nozzle 1. A low-pressure seat surface 36 is formed in a path communicating with the pressure chamber 16. The valve body 34 described above is disposed between the high pressure seat surface 35 and the low pressure seat surface 36.

  In the above configuration, when the piezo actuator 2 is contracted, the valve body 34 is in contact with the low pressure seat surface 36 and the back pressure chamber 16 is connected to the high pressure passage 6 as shown in FIG. Fuel pressure is introduced. The needle 13 is urged in the valve closing direction by the fuel pressure in the back pressure chamber 16 and the spring 14 to close the nozzle hole 11.

  On the other hand, when the electric charge of the piezo actuator 2 is discharged and the piezo actuator 2 is extended, the valve body 34 is in contact with the high pressure seat surface 35, the back pressure chamber 16 is connected to the low pressure passage 7, and the back pressure chamber 16 has a low pressure. become. The needle 13 is urged in the valve opening direction by the fuel pressure in the high-pressure chamber 15 to open the injection hole 11, and fuel is injected from the injection hole 11 into the cylinder of the internal combustion engine.

  Next, a specific configuration of the injector of this embodiment will be described. 3 is an enlarged cross-sectional view of a portion A in FIG. 1, and FIG. 4 is a cross-sectional view taken along line BB in FIG.

  As shown in FIGS. 1, 3, and 4, the storage hole 41 of the injector body 4 includes three cylindrical storage holes 41 a to 41 c. One end of the first storage hole 41 a opens at the nozzle side end face of the injector body 4, and extends from the nozzle side end face of the injector body 4 toward the opposite nozzle side of the injector body 4.

  The second storage hole 41b has a smaller diameter than the first storage hole 41a, and extends from the end on the non-nozzle side of the first storage hole 41a toward the anti-nozzle side of the injector body 4.

  The third storage hole 41c has a smaller diameter than the second storage hole 41b, one end opens on the end surface on the side opposite to the nozzle of the injector body 4, and the other end is connected to the second storage hole 41b. The first storage hole 41a, the second storage hole 41b, and the third storage hole 41c are arranged coaxially.

  The piezoelectric actuator 2 is stored in the first storage hole 41a and the second storage hole 41b, and the lead wire 22 and the holding member 8 are stored in the third storage hole 41c.

  An insulating member 23 made of an insulating material such as a resin is disposed at the opposite end of the piezoelectric actuator 2 on the nozzle side. The two terminals 24 connected to the piezo stack 21 are welded to the lead wires 22 at the protruding end portions 241 that are portions that protrude from the insulating member through holes 231 through the insulating member through holes 231 of the insulating member 23. Yes.

  Two cylindrical insulating cylinder portions 233 projecting from the main body portion 232 of the insulating member 23 toward the holding member 8 are formed at the opposite end portion of the insulating member 23 (that is, the holding member side end portion). Yes.

  A portion of the insulating cylinder portion 233 located between the protruding end portions 241 of the two terminals 24 corresponds to the partition portion 233a. Incidentally, the part which gave the twill pattern for convenience in FIG. 4 is the partition part 233a.

  The holding member 8 is made of a material having a hardness lower than that of a metal, for example, a resin such as nylon, in order to prevent the coating of the lead wire 22 from being worn. In addition, the holding member 8 has a shape, a thickness, and the like set so that the rigidity is higher than that of the lead wire 22.

  The holding member 8 has a cylindrical shape, and two holding member through holes 81 into which the lead wires 22 are inserted are formed continuously from one end to the other end of the holding member 8. In other words, the two holding member through holes 81 are separated by the partition wall portion 82. The holding member through hole 81 corresponds to the insertion space of the present invention.

  Next, assembly of the piezo actuator 2 to the injector body 4 will be described.

  First, the terminal 24 and the lead wire 22 of the piezo actuator 2 are welded. Subsequently, the lead wire 22 is inserted into the holding member through hole 81 of the holding member 8 until the end portion of the holding member 8 comes into contact with the end portion of the piezoelectric actuator 2. In this state, the insulating cylinder portion 233 also enters the holding member through hole 81.

  Here, when the spatter that is generated when welding the terminal 24 and the lead wire 22 and is unstablely adhered to the welded part falls off when the lead wire 22 and the holding member 8 are assembled, the spatter S (FIG. 3) falls around the insulating cylinder 233. Further, since the contact between the dropped spatter S and the terminal 24 is blocked by the insulating cylinder portion 233, a short circuit between the two terminals 24 due to the dropped sputter S is prevented.

  Subsequently, the integrated piezo actuator 2, lead wire 22, and holding member 8 are assembled to the injector body 4 as follows.

  First, the lead wire 22 and the tip of the holding member 8 are inserted from the nozzle side opening in the storage hole 41. Subsequently, the piezo actuator 2 is inserted so as to be pushed into the storage hole 41. Here, since the lead wire 22 is held by the holding member 8 having high rigidity except for the tip, the bending of the lead wire 22 is prevented in the process of pushing the piezoelectric actuator 2 into the storage hole 41. Therefore, as the piezo actuator 2 is pushed into the storage hole 41, the lead wire 22 and the holding member 8 can smoothly move through the storage hole 41.

  Then, when the piezo actuator 2 is pushed into the second storage hole 41 b, the leading end of the lead wire 22 protrudes from the non-nozzle side opening in the storage hole 41.

  Subsequently, the protruding tip of the lead wire 22 is joined to a terminal (not shown) at the non-nozzle side end of the injector body 4. Thereafter, as shown in FIG. 1, the connector housing 9 is molded.

  According to the present embodiment, the contact between the dropped spatter S and the terminal 24 is blocked by the partition portion 233a of the insulating cylinder portion 233, so that a short circuit between the two terminals 24 due to the dropped spatter S is prevented.

  In addition, in the said embodiment, although a part of insulation cylinder part 233 comprised the partition part 233a, like the modification shown in FIG. 5, the cylindrical insulation cylinder part 233 was abolished and plate shape The partition part 233a may be used. Incidentally, FIG. 5 corresponds to a sectional view taken along the line CC of FIG.

  Moreover, in the said embodiment and modification, although the two insulation cylinder parts 233 or the partition parts 233a were provided, they may be one. In this case, even if the sputter contacts one terminal, since the contact with the other terminal is blocked by the insulating cylinder portion 233 or the partition portion 233a, it is possible to prevent a short circuit between the terminals due to the dropped spatter.

(Second Embodiment)
A second embodiment of the present invention will be described. FIG. 6 is a cross-sectional view showing the main part of the injector according to the second embodiment, and FIG. 7 is a cross-sectional view of the insulating member and the terminal along the line CC in FIG.

  In the present embodiment, the specific configuration of the insulating cylinder portion 233 is changed, and the others are the same as those in the first embodiment, and therefore only different portions will be described.

  As shown in FIGS. 6 and 7, the insulating member 23 and the two terminals 24 are integrated by insert molding. A groove portion 234 extending in a direction orthogonal to the axis of the insulating member 23 is formed between the two insulating cylinder portions 233.

  Then, the partition wall portion 82 of the holding member 8 enters the groove portion 234, and the insulating member 23 extends to the holding member through-hole of the holding member 8 until the end of the partition wall portion 82 contacts the bottom portion of the groove portion 234. 81 is inserted.

  In addition, the site | part located between the protrusion edge parts 241 of the two terminals 24 among the insulation cylinder parts 233, in other words, the both-sides part of the groove part 234 is equivalent to the partition part 233a. Incidentally, the part which gave the twill pattern for convenience in FIG. 7 is the partition part 233a.

  According to the present embodiment, the sputter that has dropped and dropped into the groove portion 234 when the lead wire 22 is inserted into the holding member through hole 81 of the holding member 8 is brought into contact with the terminal 24 by the partition portion 233a of the insulating cylinder portion 233. Therefore, the short circuit between the two terminals 24 due to the spatter S falling off is prevented.

(Other embodiments)
In each of the above embodiments, the pressure control means for controlling the pressure in the back pressure chamber is configured by the piezo actuator 2 and the back pressure control mechanism 3, but the pressure control means may be an electromagnetic valve.

  Each of the above embodiments can be arbitrarily combined within a practicable range.

1 nozzle 2 piezo actuator 3 back pressure control mechanism (pressure control means)
4 Injector body 8 Holding member 22 Lead wire 23 Insulating member 24 Terminal 41 Storage hole 81 Insertion space 241 Projection end 233a Partition

Claims (3)

A nozzle (1) that opens or closes according to the pressure in the back pressure chamber and injects fuel when the valve is opened;
A cylindrical injector body (4) having a storage hole (41) penetrating from one end side to the other end side;
Pressure control means (2, 3) that is housed in the housing hole (41) and controls the pressure of the back pressure chamber in response to an electrical signal;
Two power supply lead wires (22) welded at one end to the two terminals (24) of the pressure control means (2, 3);
The lead wire has a higher rigidity than that (22) and each of said lead two insertion spaces (22) is inserted (81), the partition wall separating the two insertion spaces (81) (82) And a holding member (8) formed with
With the lead wire (22) inserted into the insertion space (81), the lead wire (22) and the holding member (8) are inserted into the storage hole (41) from one end side, and the lead wire In the injector configured to take out the other end of (22) from the other end side of the storage hole (41),
The two terminals (24) are held by an insulating member (23) made of an insulating material, and the lead wire (22) at a protruding end portion (241) which is a portion protruding from the insulating member (23). And welded with
The insulating member (23) includes a partition portion (233a) located between the two protruding end portions (241) and protruding toward the holding member (8) side,
A groove portion (234) extending in a direction orthogonal to the axis of the insulating member (23) is formed in the partition portion (233a), and the partition wall portion (82) of the holding member (8) is formed in the groove portion (234). ) Entered,
The said partition part (233a) is inserted in the said insertion space (81), The injector characterized by the above-mentioned.   The injector according to claim 1, wherein the partition part (233a) has a plate shape.   2. The injector according to claim 1, wherein the partition part (233 a) is a part of a cylindrical member through which the protruding end part (241) passes.

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