JP2011001892A - Injector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce fuel leak during valve closing over a long period of time without rising cost in an injector for supplying fuel to an engine.SOLUTION: The injector includes a seat member 11A having a seat section 110A, a valve member 12 having a valve element section 12a, and a valve driving means for reciprocating the valve member 12, in which the valve element section 12a is fitted to or separated from the seat section 110A by reciprocating the valve member 12 by the valve driving means to thereby open and close a valve, and fuel introduced to the inside thereby is injected and supplied to the engine. The seat section 110A has, on the surface side, a film 112 made of a metal lower in hardness than the metal constituting the surface of the valve element section 12a, and the film 112 is deformed according to the surface shape of the valve element section 12a by pressing of the valve element section 12a associated with valve closing operation. Therefore, the surface of the seat section 110A is closely fitted to the surface of the valve element section 12a when the valve is closed to exhibit a predetermined level or more of sealing performance.

Description

  The present invention relates to an injector that injects and supplies fuel to an engine, and more particularly to an injector that suppresses fuel leakage when a valve is closed to a predetermined level or less.

  An injector (fuel injection valve) for supplying fuel to an engine includes a seat member whose opening / closing valve has a conical seat portion, and a ball-shaped or conical valve body portion (valve) disposed oppositely. The valve member is generally configured to open and close the valve by closely contacting and separating the valve body surface from the seat surface (sheet surface).

  FIG. 4 shows the configuration of the on-off valve 10B in such a conventional injector, and the engine is adjusted while adjusting the flow rate by intermittently lifting the valve body portion 12a on the front end side of the valve member 12 from the surface of the seat portion 110B. To supply fuel. Further, when the engine is stopped, the surface of the valve body 12a is brought into close contact with the surface of the seat 110B, thereby exhibiting a sealing function and shutting off the fuel.

  However, in such a sheet member 11B, the sheet portion 110B that forms the sheet surface is formed on the bare metal surface 111 by processing by cutting or the like, so that the surface state depends on the level of processing accuracy. As shown in the circle, when the processing accuracy of the metal surface 111 is rough and the unevenness is relatively large, a gap is formed in the close contact portion between the surface of the valve body portion 12a and the surface of the seat portion 110B, and the fuel is transmitted through this portion. Is known to leak.

  Therefore, when processing the surface of the sheet portion 110B, the finishing accuracy is increased to improve the surface roughness to a predetermined level or more, or a seal made of an elastic material is used for the seat portion as described in JP-A-7-229578. It is common to secure a sealing performance at a predetermined level or more by providing a member or the like.

  However, when the finishing accuracy of the surface of the sheet part 110B is increased, a relatively high level of processing technology / manufacturing equipment is required, resulting in high costs. In addition, when the sealing member is provided on the seat portion 110B, there is a problem that the number of parts is increased and the cost is increased, and the sealing member is easily deteriorated, so that the sealing performance is lowered due to aging. .

Japanese Unexamined Patent Publication No. 7-229578

  The present invention is intended to solve the above-described problems, and an injector for supplying fuel to an engine can reduce fuel leakage at the time of valve closing over a long period of time without causing an increase in cost. The task is to do.

  Therefore, the present invention includes a seat member having a seat portion, a valve member having a valve body portion, and valve drive means for reciprocating the valve member, and the valve member is reciprocated by the valve drive means. In an injector for supplying a fuel by injecting fuel into the engine by opening and closing the valve by causing the valve body portion of the valve member to closely contact and separate from the seat portion of the seat member that is disposed by operating the valve member The seat portion has a coating made of a metal having a hardness lower than that of the metal constituting the surface of the valve body portion on the front surface side, and the coating is applied by pressing the valve body portion during a valve closing operation. The valve body is deformed according to the surface shape of the valve body, and when the valve is closed, the surface of the seat and the surface of the valve body are brought into close contact with each other to exhibit a sealing performance of a predetermined level or more.

  In this way, a coating is provided on the surface of the seat portion with a metal having a lower hardness than the surface of the valve body portion, and the coating is deformed by the pressure of the valve body portion accompanying the valve closing operation, whereby the valve body surface and the seat portion are closed. Desirable sealing performance over a long period of time without requiring processing of a high-precision sheet surface or adding a sealing member made of an elastic material, so that the surface is in close contact with high precision It will be easier to secure than the level.

  Further, in this case, if the coating is made of a copper alloy, it is easy to process and low cost, and easily exhibits a good sealing performance when the valve is closed. If it is characterized by containing germanium in an amount of 10 to 99% by weight, it is easy to adjust the hardness and is resistant to corrosion and excellent in durability.

  Furthermore, in the above-described injector, if a layer formed by a chromium thin film treatment is provided between the coating on the surface side of the seat portion and the surface of the bare metal, the sealing performance when the valve is closed can be obtained. It is easier to increase and more durable.

  In addition, in the above-described injector, if the surface of the base metal of the sheet portion is finished to have a surface roughness of 0.8S to 6.3S, a relatively soft coating is deformed by use. However, even if it is worn down, the metal constituting the coating slips on the surface of the bare metal that has been finished relatively rough and most of the metal remains, so that the sealing performance at the time of closing the valve can be further ensured over a long period of time.

  According to the present invention in which a coating of a metal having a lower hardness than the metal on the surface of the valve body is provided on the surface of the seat portion, fuel leakage at the time of closing the valve can be reduced over a long period of time without causing an increase in cost. Is.

It is a fragmentary longitudinal cross-sectional view which shows the structure of the on-off valve of the injector which is embodiment in this invention, and is a partial enlarged view which shows the structure of the part which the sheet | seat part and valve body part closely_contact | adhere in a circle. It is the elements on larger scale which show the state of the use initial stage of the part which the sheet | seat part and valve body part of the injector of FIG. 1 contact | adhere. It is the elements on larger scale which show the state of the use process of the part which the sheet | seat part and valve body part of the injector of FIG. 1 contact | adhere. It is a partial longitudinal cross-sectional view which shows the structure of the on-off valve of the injector in a prior art example, and is a partial enlarged view which shows the state of the part which the sheet | seat part and valve body part closely_contact | adhere in a circle.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 shows a configuration of an on-off valve 10A for an injector according to an embodiment of the present invention. The injector according to the present embodiment includes valve drive means including an electromagnetic coil, a fixed iron core, a movable iron core, etc. (not shown). The valve member 12 reciprocally slides along the central axis together with the movable iron core of the valve drive means. The distal end side constitutes a valve body portion 12a made of a steel ball or the like, and the sheet member 11A disposed on the downstream side thereof is brought into close contact with and separated from the surface (sheet surface) of the seat portion 110A having a conical shape. As a result, the valve is closed and opened.

  The above configuration is similar to that of the conventional injector shown in FIG. 4 and is already well known. However, in the present embodiment, of the on-off valve, the seat portion 110A that forms the seat surface in the seat member 11A. The configuration is different. That is, the seat member 11A is formed with a seat surface on which the valve body portion 12a is seated by being cut out in a conical shape from the surface facing the valve member 12, and the seat portion 110A that forms the seat surface is It has a coating 112 made of a metal having a lower hardness than that of the metal constituting the surface of the valve body 12a and the metal constituting the seat member 11A on the surface side, and the valve body 12a associated with the valve opening operation By pressing, the coating 112 is slightly deformed according to the surface shape (spherical surface) of the valve body 12a, so that the surface of the seat portion 110A and the surface of the valve body 12a are easily in close contact with each other.

  For example, when the sheet member 11A and the valve member 12 are made of steel (including stainless steel), the metal forming the coating 112 is easy to work in addition to having a lower hardness and causing appropriate deformation. A low-cost copper alloy (copper-based metal) is suitable. Particularly, a copper alloy containing germanium in the range of 10 to 99% by weight is easy to adjust the hardness to an appropriate level and corrodes. Strongly recommended because it is easy to ensure durability over a long period of time.

  In addition to providing the coating 112 directly on the bare metal surface 111 constituting the base of the sheet portion 110A as a thin film treatment, as shown in FIG. 1 circle, a thin chrome film is provided between the bare metal surface 111 and the coating 112. By providing the plating layer 113, the sealing performance and durability when the valve is closed can be further ensured.

  Then, the metal surface 111 of the sheet part 110A is finished to a relatively rough state with a surface roughness in the range of 0.8S to 6.3S, so that the coating 112 is caused by friction with the valve body part 12a with use. Even when it is worn out while being deformed, the metal constituting the coating 112 slips into the concave and convex portions formed on the surface 111 of the bare metal, and most of the metal remains, so that the seal when the valve is closed for a longer period of time. Performance can be secured.

  The operation of the characteristic portion of the injector in the present embodiment will be described in detail with reference to FIGS. 2 and 3. FIG. 2 shows an initial state of the seat portion 110A in use of the injector according to the present embodiment, and its valve body portion 12a. And the seat part 110A are in close contact with each other. As described above, the coating 112 of the uppermost layer of the seat portion 110A has a lower hardness and is softer than the surface of the valve body portion 12a. The degree of adhesion increases. Therefore, the sealing performance is higher than that of the conventional example shown in FIG.

  FIG. 3 shows the state of the use process in the seat part 110A after a certain period of use from the state of FIG. 2, but the valve body part 12a and the seat part 110A overlap each other in the use process of the injector. Due to the collision action, the relatively soft coating 112 is worn while being deformed. However, since the finishing accuracy of the bare metal surface 111 is rough, most of the metal that has formed the coating 112 slips into the concave and convex recesses, so that most of it remains and maintains its high adhesion for a long time. A high sealing performance is ensured.

  As described above, the injector of the present embodiment has a very simple configuration of the seat surface 110A of the seat member 11A that constitutes the on-off valve 10A, and does not require advanced technology or equipment to form this. In addition, it is possible to ensure the sealing performance at the time of valve closing over a long period of time without using a sheet member made of an elastic material that easily deteriorates.

  As described above, with respect to the injector that supplies fuel to the engine, the present invention has made it possible to avoid fuel leakage at the time of closing the valve for a long period of time without causing an increase in cost.

10A on-off valve, 11A sheet member, 12 valve member, 12a valve body part, 110A sheet part, 111 bare metal surface, 112 coating, 113 chrome plating layer

Claims (5)

  A seat member having a seat portion, a valve member having a valve body portion, and valve drive means for reciprocating the valve member, and by reciprocating the valve member by the valve drive means, In the injector that supplies the fuel introduced into the engine by opening and closing the valve by closely contacting and separating from the seat portion of the seat member that is disposed to face the valve body portion, the seat portion is: It has a coating made of a metal having a hardness lower than that of the metal constituting the surface of the valve body portion on the surface side, and the surface shape of the valve body portion is formed by pressing the valve body portion during valve closing operation. The injector is deformed according to the above, and the surface of the seat part and the surface of the valve body part are brought into close contact with each other when the valve is closed to exhibit a sealing performance of a predetermined level or more.   The injector according to claim 1, wherein the coating is made of a copper alloy.   The injector according to claim 2, wherein the copper alloy contains 10 to 99% by weight of germanium.   4. The injector according to claim 1, wherein a chromium thin film treatment layer is provided between the coating on the surface side of the sheet portion and the surface of the bare metal. The injector according to claim 1, 2, 3, or 4, wherein the surface of the sheet metal has a surface roughness of 0.8S to 6.3S.

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