Method of producing fuel distribution pipe |
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申请号 | EP13002143.9 | 申请日 | 2013-04-23 | 公开(公告)号 | EP2667011A2 | 公开(公告)日 | 2013-11-27 |
申请人 | Otics Corporation; | 发明人 | Isogai, Eiji; Ota, Takayoshi; | ||||
摘要 | The present invention provides a method of producing a fuel distribution pipe 10 to be attached to a cylinder head. The method includes providing a forged bar made of metal, forming a main bore 14 in the forged bar so as to extend along an axial direction of the forged bar, forming an injector bore 25 having an injector opening in the forged bar, forming a bolt through hole 22 having a bolt opening in the forged bar, obtaining a base pipe having the main bore 14, the injector bore 25, and the bolt through hole 22 from the forged bar, and bending the base pipe such that the injector opening of the injector bore 25 and the bolt opening of the bolt through hole 22 are provided along a line parallel to the axis of the main bore. The injector bore 25 directly communicates with the main bore 14 and the bolt through hole 22 does not communicates with the main bore 14. | ||||||
权利要求 | |||||||
说明书全文 | The present disclosure relates to a method of producing a fuel distribution pipe. For example, a known fuel distribution pipe used in an internal-combustion engine includes a pipe, a bolt attachment portion, and an injector attachment portion. The pipe includes a pipe bore through which fuel flows. The pipe is fixed to a cylinder head with a bolt that is passed through a bolt through hole of the bolt attachment portion. The injector attachment portion includes an injector bore that communicates with the pipe bore. An injector is attached to the injector attachment portion such that the fuel can be supplied from the pipe to the injector through the injector bore. Such a fuel distribution pipe is described in The present technology has been made in view of the aforementioned circumstances. An objective of the present technology is to provide a method of producing a fuel distribution pipe in which the injector bore and the pipe bore are directly connected to communicate with each other and the bolt through hole and the injector bore are provided such that an opening of the bolt through hole and an opening of the injector bore are arranged on a line parallel to the pipe. A technology described herein relates to a method of producing a fuel distribution pipe to be attached to a cylinder head. The method includes providing a forged bar made of metal, forming a main bore in the forged bar so as to extend along an axial direction of the forged bar, forming an injector bore having an injector opening in the forged bar, forming a bolt through hole having a bolt opening in the forged bar, obtaining a base pipe having the main bore, the injector bore, and the bolt through hole from the forged bar, and bending the base pipe such that the injector opening of the injector bore and the bolt opening of the bolt through hole are provided along a line parallel to the axis of the main bore. Fuel is allowed to flow through the main bore. The injector bore directly communicates with the main bore. The injector bore is configured to receive an injector therein through the injector opening. The bolt through hole does not communicate with the main bore. A bolt is passed through the bolt through hole to fix the pipe to the cylinder head. According to the above-described method, the injector opening of the injector bore and the bolt opening of the bolt through hole are provided along a line parallel to the axis of the main bore. Accordingly, even when a reaction force from the cylinder side is applied to uplift the pipe through the injector attachment portion at the time of injection of fuel, a force to rotate the pipe on the bolt attachment portion is hardly generated. Therefore, the uplift of the pipe is less likely to occur. Further, according to the above-described method, the injector bore and the pipe bore are connected to directly communicate with each other. This eliminates a step of forming a diagonal communication hole and improves the productivity and workability. In addition, even if a burr is generated at an intersection between the injector bore and the pipe bore, the burr is easily visible from an opening of the injector bore, because the intersection is located at the most remote end of the injector bore, not the diagonal communication hole. This facilitates the deburring. The bending step may include bending a portion of the base pipe in which the injector bore is formed such that the injector opening and the bolt opening are provided along the line parallel to the axis of the main bore. This requires only a small area around the injector bore to be bent. If the bending step include bending a portion of the base pipe in which the bolt through hole is formed, a larger area is required to be bent, because the area extending over the bolt through hole and the main bore is required to be bent. Accordingly, the configuration facilitates the bending step. The base pipe may be bent such that an axis of the injector bore and an axis of the bolt through hole intersect with the axis of the main bore of the base pipe. The base pipe may be bent such that an center of the injector opening and an center of the bolt opening are provided along the line parallel to the axis of the main bore. The forged bar may include an extended portion and a protruded portion. The extended portion may extend away from the main bore and the bolt through hole may be formed in the extended portion. The injector bore may be formed in the protruded portion. The method may further include inserting a diameter retaining member into the main bore of the base pipe before the bending step, and removing the diameter retaining member from the main bore after the bending step. The diameter retaining member maintains a diameter of the main bore during the bending step. Thus, the diameter of the main bore is hardly changed by the bending step. The diameter retaining member may have an outer diameter that is substantially equal to an inner diameter of the main bore. The diameter retaining member may include a plurality of metal balls connected with each other via a link. The forming step of forming the injector bore may include drilling the forged bar at a right angle with respect to the main bore. The axis of the injector bore and the axis of the bolt through hole may be parallel with each other. The bending step may include pressing the base pipe to be bent. The base bar can be easily bent by the press. The forming step of forming the bolt through hole may include forming a plurality of bolt through holes, and the forming step of forming the injector bore may include forming a plurality of injector bores. Each of the injector bores may be formed between adjacent two of the bolt through holes. An objective of the present technology may be embodied as a fuel distribution pipe produced according to the method described above. The technology of the present invention provides a method of producing a fuel distribution pipe in which a pipe bore and an injector bore are directly connected to communicate with each other, and a bolt through hole and the injector bore are provided such that an opening of the bolt through hole and an opening of the injector bore are arranged on a line parallel to the axis of the main bore.
In the above-described related art, the injector bore intersects with the pipe bore, but the bolt through hole does not intersect with the pipe bore and is located outwardly away from the pipe bore. In such a configuration, if a reaction force is applied to the pipe from the cylinder side at the time of injection, a force is generated to rotate the pipe on the bolt attachment portion. This may cause an uplift of the pipe. This problem may be solved by providing the bolt attachment portion and the injector attachment portion such that axes thereof intersect with a line that is parallel to a longitudinal direction of the pipe. Accordingly, a rotation force around the bolt bore is not generated and the uplift of the pipe is less likely to occur. To obtain the fuel distribution pipe having such an arrangement of the bolt attachment portion and the injector attachment portion, the injector bore may be provided to intersect with the longitudinal direction extending through the bolt bore. However, since the bolt bore does not intersect with the pipe bore, the injector bore does not intersect with the pipe bore. Thus, a communication hole is necessary to be formed to communicate the injector bore and the pipe bore. In the formation of the communication hole, a drilling from an inside of the bore of the injector attachment portion in a diagonal direction is required. This lowers productivity and workability. In addition, the formation of the communication hole may generate a burr at an intersection between the communication hole and the pipe bore. This burr may not be easily visible from an opening of the injector bore, because the intersection is located at the most remote end of the communication hole from the opening of the injector bore. Accordingly, the burr may be difficult to be removed. A method according to the present technology and a fuel distribution pipe produced by the method will be explained with reference to As illustrated in The pipe 20 has a pipe bore 23 extending along its axial direction. The pipe bore 23 includes a straight section and a curved section in which the pipe bore 23 extends straightly and curvedly, respectively. The pipe bore 23 and an injector bore 25, which will be described later, communicate with each other at the curved section. Herein, a direction extends parallel with an axis of a main bore 14 of a base pipe 11, which will be described later, is referred to as a longitudinal direction. The longitudinal direction corresponds to a right-left direction in The pipe 20 includes the injector attachment portions 24 and an injector is attached to each of the injector attachment portions 24. The number of the injector attachment portions 24 corresponds to that of the cylinders. Each of the injector attachment portions 24 is located between adjacent two of the bolt attachment portions 21 in the longitudinal direction. The adjacent two bolt attachment portions 21 are arranged such that at least one of them is located adjacent to the injector attachment portion 24 in the longitudinal direction. As illustrated in An injector is inserted into the injector bore 25 from the opening of the injector attachment portion 24. The injector is a fuel injection device that injects fuel into the cylinder of an engine. The fuel supplied to the pipe bore 23 is distributed to the injectors through the injector bores 25. Then, the injectors inject the fuel to the cylinders of the engine. The axis 23P of the pipe bore 23 intersects with the axis 25P of the injector bore 25 at a right angle, and thus the pipe bore 23 and the injector bore 25 are directly connected to communicate with each other. Accordingly, a communication hole that connects the pipe bore 23 and the injector bore 25 is not required. As illustrated in In this configuration, the opening of the bolt through hole 22 and the opening of the injector bore 25 are provided on the line parallel to the longitudinal direction of the pipe 20. Each of the axis 22P of the bolt through hole 22 and the axis 25P of the injector bore 25 intersects with the longitudinal direction and intersects with a line parallel to the longitudinal direction. The center of the bolt through hole 22 and the center of the injector bore 25 are provided on the line parallel to the longitudinal direction of the pipe 20. Accordingly, even if a reaction force from the cylinder side is applied to the pipe 20 through the injector attachment portion 24 at the time of injection of the fuel, a force to rotate the pipe 20 about the bolt through hole 22 is hardly generated. Therefore, the uplift of the pipe 20 is less likely to occur. As illustrated in The fuel delivery pipe 10 produced by the method according to the present technology has the above-described configuration. Next, the method of producing the fuel delivery pipe 10 is explained. Initially, a forged bar that is formed in substantially a tubular shape is provided as a base material for the pipe 20. The forged bar is made of an iron material such as carbon steel material. The forged bar includes the cylindrical extended portion 13 extending in a direction perpendicular to the longitudinal direction, i.e., in a lower direction in As illustrated in Then, as illustrated in As described above, according to the method, the bolt through hole 22 and the injector bore 25 are formed in the base pipe 11, and then the base pipe 11 is pressed at the protruded portion 12 including the injector bore 25. Thus, the base pipe 11 is bent such that each of the bolt through hole 22 and the injector bore 25 intersects with the line parallel to the axis of the main bore 14. Accordingly, the opening of the bolt through hole 22 and the opening of the injector bore are provided on the line parallel to the longitudinal direction of the pipe 20. Further, the center of the bolt through hole 22 and the center of the injector bore 25 are provided on the line parallel to the longitudinal direction of the pipe 20. With this configuration, the pipe 20 is hardly rotated upon the injection of fuel. In addition, the axis 25P of the injector bore 25 and the axis 23P (the center) of the pipe bore 23 intersect with each other at a right angle. In this configuration, the injector bore 25 and the pipe bore 23 are directly connected to communicate with each other. Thus, even if a burr is generated at the intersection between the injector bore 25 and the pipe bore 23, the burr can be easily removed. The present invention is not limited to the embodiment as described above with reference to the drawings. (1) The axis 23P (the center) of the pipe bore 23 and the axis 25P of the injector bore 25 may not intersect at a right angle, but may be arranged at any angle on the same plane. (2) The base pipe may not be bent at the injector attachment portion 24. The base pipe may be bent at the bolt through hole 22, or at both of the injector bore 25 and the bolt through hole 22. (3) The diameter retaining members is not limited to the metal balls. Any diameter retaining member that can retain diameter of the main bore may be used. (4) The metal balls of the diameter retaining member 30 may not be connected to each other. Metal balls that are not connected to each other may be used as the diameter retaining member. In such a case, both ends of the main bore 14 may be closed with covers during the bending step. (4) The forged bar may not be bent by a press. The forged bar may be bent by a forging. (5) One injector attachment portion 24 may not be located between two bolt attachment portions 21. Only one bolt attachment portion may be provided for one injector attachment portion. (6) The fuel delivery pipe may not be the fuel delivery pipe 10 for a gasoline engine. The fuel delivery pipe may be a common rail for a diesel engine. 10: fuel delivery pipe, 11: base pipe, 14: main bore, 14P: pipe axis, 20: pipe, 21: bolt attachment portion, 22: bolt through hole, 23: pipe bore, 24: injector attachment portion, 25: injector bore, 30: diameter retaining member |