Structure for connecting connectors

Abstract

According to the present invention, wear of a portion where a connector is connected to a fuel injection valve is reduced. The present invention has an impact reduction structure in which, in a state in which an insertion part (53) of a connector (50) is inserted into an insertion hole (48) of a fuel injection valve (30), a first space (81) formed by a first groove part (46a, 46b) of the fuel injection valve (30) and a second space (83) formed by a second groove part (52) of the connector (50) are in communication with each other, and a clip (60, 65) engages the first space (81) and second space (83), which are in communication with each other, to connect the connector (50) to the fuel injection valve (30), thereby reducing an impact generated by relative movement of a connection part (45) and the connector (50) in mutually opposite directions along the insertion direction of the connector (50).

Description

[0001]

Document Name

[0002]

Title of the Invention

[0003]

Technical Field

[0004]

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[0005]

Background Art

[0006]

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[0007]

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[0008]

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[0009]

Prior Art Documents

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Patent Documents

[0011]

〇 0 0 5

[0012] [Patent Document 1] Japanese Unexamined Patent Publication No. 2011-122462

[0013] [Summary of the Invention]

[0014] [Problems the invention aims to solve]

[0015] [〇 0 0 6] Here, during the operation of the internal combustion engine, vibrations of the engine generate stress on the return piping and connector. In addition, the high-pressure fuel discharged from the pressure control chamber generates stress that pushes the return piping and connector away from the fuel injector. As a result, the connection surfaces of the connector, clip and fuel injector may collide and wear down. If this wear progresses and the total amount of wear on each part increases, the position of the O ring may move out of the proper position, which may lead to fuel leakage.

[0016] [〇 0 0 7] The present invention has been made in view of the above problems, and provides a connector connection structure that can reduce wear at the location where the connector is connected to the fuel injection valve.

[0017] [Means for solving the problem]

[0018] [〇 0 0 8] In order to solve the above problem, according to one aspect of the present invention, a connection structure in which a connector is connected to a fuel injector, wherein the fuel injector comprises a cylindrical connecting portion having an insertion hole into which the connector is inserted, and a first groove provided on the outer circumference of the connecting portion, the bottom of which penetrates the insertion hole, and the connector comprises a cylindrical insertion portion that is inserted into the insertion hole, and a second groove provided on the outer circumference of the insertion portion, wherein with the insertion portion of the connector inserted into the insertion hole of the fuel injector, the first space formed by the first groove and the second space formed by the second groove are connected to each other, and a clip is locked in the connected first space and second space to connect the connector to the fuel injector, A connector connection structure is provided which has an impact mitigation structure that reduces the impact caused by the relative movement of the connecting portion and the connector in opposite directions along the insertion direction of the connector.

[0019] [Effects of the Invention]

[0020] [0 0 0 9] As described above, according to the present invention, wear at the location where the connector is connected to the fuel injection valve can be reduced.

[0021] [Brief explanation of the drawing]

[0022] [0 0 1 0]

[0023] [Figure 1] This is a configuration diagram showing an example of a fuel injection system for an internal combustion engine to which the connector connection structure according to the embodiment of this disclosure is applied.

[0024] [Figure 2] This is a schematic diagram showing an example of the basic configuration of a fuel injection valve to which the connector connection structure according to the present embodiment is applied.

[0025] [Figure 3] This is an exploded perspective view of the connector connection structure according to the first embodiment.

[0026] [Figure 4] This is a side view of the connector connection structure according to the same embodiment.

[0027] [Figure 5] This is a cross-sectional view of the I-I section in Figure 4, taken in the direction of the arrow.

[0028] [Figure 6] This is a cross-sectional view of section II-II in Figure 4, taken in the direction of the arrow.

[0029] [Figure 7] This is a side view of the connection structure of a conventional connector.

[0030] [Figure 8] This is a partial cross-sectional view of the III-III section of Figure 7, taken in the direction of the arrow.

[0031] [Figure 9] This is a side view of the connector connection structure according to the second embodiment.

[0032] [Figure 10 is a partial cross-sectional view of the V section as seen in the direction of the arrow.]

[0033] [Implement the invention]

[0034] [ 0 0 1 1 Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. In this specification and drawings, components having substantially the same functional configuration are denoted by the same reference numeral, and redundant explanations will be omitted. In the following description, the directions of up, down, left, and right refer to the directions of up, down, left, and right as shown in the figures.

[0035] [0 0 1 2]

[0036] <Fuel Injection System> First, an example of a fuel injection system for an internal combustion engine to which the connector connection structure according to each embodiment of the present disclosure can be applied will be described.

[0037]

[0013] Figure 1 shows an example of the configuration of a fuel injection system for a diesel engine having a connector connection structure according to this embodiment. The fuel injection system 1 is constructed as a common rail system equipped with an accumulator (common rail) 19. In this embodiment, the internal combustion engine is a diesel engine, but the type of internal combustion engine is not particularly limited.

[0038] [0 0 1 4] The fuel injection system 1 comprises a fuel tank 3, a feed pump (low-pressure pump) 5 that discharges fuel from the fuel tank 3, a fuel supply pump (high-pressure pump) 11 that pressurizes and pumps fuel, a common rail 19 that stores the fuel pumped from the fuel supply pump 11, and a fuel injector 30 that injects the fuel distributed by the common rail 19 into the cylinders of the internal combustion engine.

[0039] [0 0 1 5] The feed pump 5 discharges fuel (diesel) from the fuel tank 3 and supplies the fuel to the fuel supply pump 1 1 via the low-pressure passage 7. The feed pump 5 may be an electric pump or a gear pump that is rotationally driven by the power of the internal combustion engine. A filter 9 is provided in the middle of the low-pressure passage 7.

[0040] [0 0 1 6] The fuel supplied from the feed pump 5 is supplied to the pressurized chamber of the fuel supply pump 11, with its flow rate controlled by the proportional control valve 13. Excess fuel is discharged to the return pipe 25 via an overflow valve (not shown) installed in parallel with the proportional control valve 13 and returned to the fuel tank 3. The fuel supply pump 11 is rotationally driven by the power of the internal combustion engine and pressurizes the fuel supplied to the pressurized chamber, pumping it towards the common rail 19 via the high-pressure fuel passage 15.

[0041] [0 0 1 7] The common rail 19 stores the fuel pumped from the fuel supply pump 11 and distributes it to each fuel injector 30 at a uniform pressure. The common rail 19 is equipped with a pressure sensor 21 that detects the pressure within the common rail 19 (also called "rail pressure") and a pressure regulating valve that adjusts the rail pressure.

[0042] 2 and 3 are provided. The control device 17 controls the drive of the proportional control valve 13 to control the flow rate of the high-pressure fuel supplied to the common rail 19, and controls the drive of the pressure regulating valve 23 so that the rail pressure detected by the pressure sensor 21 becomes a desired pressure. The fuel discharged through the pressure regulating valve 23 is refluxed to the fuel tank 3 through the return pipe 29.

[0043]

[0018] The high-pressure fuel distributed from the common rail 19 to each fuel injection valve 30 flows into a pressure control chamber (not shown) of the fuel injection valve 30. The high-pressure fuel flowing into the pressure control chamber biases the valve body in a direction to close the injection holes. By discharging a part of the high-pressure fuel in the pressure control chamber, the biasing force of the valve body is weakened, and fuel is injected from the injection holes into the cylinder of the internal combustion engine. The control device 17 controls the drive of the fuel injection valve 30 based on the rail pressure and the target injection amount. At this time, the fuel discharged from the pressure control chamber is refluxed to the fuel tank 3 through the return pipe 27 connected to the fuel injection valve 30 using the connector 50.

[0044]

[0019]

[0045] <Fuel injection valve> Next, referring to FIG. 2, an example of the basic configuration of the fuel injection valve will be briefly described.

[0046]

[0020] FIG. 2 shows a cross-sectional view of the fuel injection valve 30. The fuel injection valve 30 includes a housing 31, a nozzle body 33, a nozzle nut 34, a needle valve 39, a piston 43, and a backflow tube 45. The nozzle body 33 is attached to the tip side of the housing 31 using the nozzle nut 34. The backflow tube 45 is attached to the rear end side of the housing 31 by press-fitting or screwing.

[0047]

[0021] The housing 31 has an axially extending hole, and a piston 43 is slidably disposed within the hole. The nozzle body 33 has an axially extending hole, and a needle valve

[0048] 39 is slidably disposed within the hole. An injection hole 32 is formed at the tip (lower end) of the hole. The holes of the housing 31 and the nozzle body 33 are provided coaxially. The piston

[0049] 43 and the needle valve 39 are each contacted by an intermediate member 41 disposed therebetween. The intermediate member 41 is constantly urged toward the needle valve 39 side by the biasing force of a spring 42, and biases the needle valve 39 toward the injection hole 32 side (valve closing direction).

[0050]

[0022] The fuel injection valve 30 includes a first fuel passage 35 and a second fuel passage 36 through which high-pressure fuel distributed from a common rail 19 passes via an inlet body (not shown). The high-pressure fuel flowing through the first fuel passage 35 is introduced into a gallery provided midway in the hole of the nozzle body 33. The pressure of the high-pressure fuel introduced into the gallery biases the needle valve 39 toward the rear end side (valve opening direction). The high-pressure fuel flowing through the second fuel passage 36 is introduced into a pressure control chamber 37 formed on the rear end side of the piston 43. The pressure of the high-pressure fuel introduced into the pressure control chamber 37 biases the piston 43 toward the tip side (valve closing direction).

[0051] [0 0 2 3] The fuel injector 30 is equipped with an on / off control valve 38 that discharges high-pressure fuel from the pressure control chamber 3. When the sum of the pressure in the pressure control chamber 37 and the biasing force of the spring 42 exceeds the pressure in the gallery, the injection port 32 is closed by the needle valve 39. On the other hand, when high-pressure fuel is discharged from the pressure control chamber 37 and the pressure in the pressure control chamber 37 decreases, and the sum of the pressure in the pressure control chamber 37 and the biasing force of the spring 42 falls below the pressure in the gallery, the needle valve 39 retracts and the injection port 32 opens, and fuel injection is performed.

[0052] [0 0 2 4] Fuel discharged from the pressure control chamber 3 7 by the on / off control valve 3 8 flows into the fuel passage 5 7 in the connector 5 0 via the fuel discharge passage 4 4, and then flows through the return pipe 2 7 to return to the fuel tank 3. The connector 5 0 is connected to a cylindrical backflow tube 4 5, which is mounted at the end opposite to the injection hole 3 2. The backflow tube 4 5 corresponds to the cylindrical connector in this disclosure.

[0053] [0 0 2 5] The connector 50 is a component obtained, for example, by molding metal or resin. The connector 50 comprises an insertion portion 53 that is inserted into an insertion hole 48 provided in the backflow tube 45 of the fuel injector 30, a head 51 that is connected above the insertion portion 53, two connection portions 55a and 55b to which the return pipe 27 is connected, and a fuel passage 57 that leads from the insertion portion 53 to the two connection portions 55a and 55b. The insertion portion 53 is a stepped cylindrical portion that extends in a predetermined axial direction, and a seal ring 71 is fitted around the outer circumference of the lower region. The sealing ring 7 1 prevents fuel from leaking to the outside by sealing the space between the inner surface of the insertion hole 4 8 of the backflow tube 4 5 and the insertion portion 5 3 of the connector 5 0.

[0054] [0 0 2 6] The two connecting parts 5 5a and 5 5b are cylindrical portions that extend in opposite directions from each other, for example, from the head 5 1 in a direction perpendicular to the insertion direction of the insertion part 5 3. The fuel passage 5 7 is a communication hole provided inside the connector 5 〇, opening at the ends of the insertion part 5 3 and the two connecting parts 5 5a and 5 5b, respectively.

[0055] [0 0 2 7] Connector 5 0 is connected to the backflow tube 4 5 of the fuel injector 3 using a clip 6 0. The fuel passage 5 7 of connector 5 0 communicates with the insertion hole 4 8 of the backflow tube 4 5, which leads to the fuel discharge passage 4 4 ​​of the fuel injector 3, and guides the fuel discharged from the pressure control chamber 3 7 to the return pipe 2 7.

[0056] [ 0 0 2 8 ]

[0057] <Connector Connection Structure> Next, an embodiment of the connector connection structure will be described in detail.

[0058] [ 0 0 2 9 ]

[0059] [First Embodiment] The connector connection structure of the present disclosure has an impact mitigation structure that mitigates the impact caused by the relative movement of the backflow tube 4 5 and the connector 50 in opposite directions along the insertion direction of the connector 50. In the connector connection structure according to the first embodiment, the impact mitigation structure includes an elastically deformable portion provided on the clip 60 that elastically deforms along the insertion direction of the connector 50.

[0060] [0 0 3 0] Figures 3 to 6 are explanatory diagrams showing the connection structure of a connector according to the first embodiment of the present disclosure. Figure 3 is an exploded perspective view showing the connector 50 connected to the backflow tube 4 5. Figure 4 is a side view of the state in which the connector 50 is connected to the backflow tube 4 5, viewed from the direction of arrow X shown in Figure 3. Figure 5 is a cross-sectional view of the I-I section of Figure 4, viewed in the direction of the arrow. Figure 6 is a cross-sectional view of the II-II section of Figure 4, viewed in the direction of the arrow.

[0061] [0 0 3 1] The backflow tube 4 5 attached to the fuel injector 3〇 has an insertion hole 4 8 into which the connector 5〇 is inserted. The backflow tube 4 5 also has two first grooves 4 6 a and 4 6 b provided on its outer circumference. The two first grooves 4 6 a and 4 6 b are provided on both sides of the insertion hole 4 8. At the bottom of each of the first grooves 4 6 a and 4 6 b is an opening 4 7 a,

[0062] A 47b is provided, and the bottoms of the first grooves 46a and 46b penetrate through the insertion hole 48. The first grooves 46a and 46b form the first spaces 81a and 81b, respectively.

[0063]

[0032] The connector 50 has a cylindrical insertion portion 53 that is inserted into the insertion hole 48 of the backflow tube 45, and a second groove portion 52 provided around the entire circumference of the outer circumference of the insertion portion 53. The second groove portion 52 forms a second space 83. With the insertion portion 53 of the connector 50 inserted into the insertion hole 48 of the backflow tube 45, the first spaces 81a, 8lb formed by the first groove portions 46a, 46b and the second space 83 formed by the second groove portion 52 are connected to each other. The second groove portion 52 is provided on the head 5I side of the position where the seal ring 71 attached to the insertion portion 53 is located. In other words, the second groove 52 is provided on the outer side of the fuel sealing point by the seal ring 71.

[0064] [00 3 3] With the insertion portion 5 3 of the connector 50 inserted into the insertion hole 48 of the backflow tube 4 5, the clip 6 0 is attached from the side of the backflow tube 4 5. As a result, the first spaces 8 1 a, 8 1 b formed by the first grooves 4 6 a, 4 6 b and the second space 8 3 formed by the second groove 5 2, which are connected to each other, are locked by the clip 6 0, and the connector 50 is connected to the backflow tube 4 5.

[0065]

[0034] The clip 6 is made of metal, for example, and is a U-shaped member including two legs 60a and 60b. The clip 60 is attached to the backflow tube 45 from the open part of the U shape. The two legs 60a and 60b of the clip 60 constitute an impact-absorbing structure having an elastically deformable portion that can be elastically deformed along the insertion direction of the connector 50 (up and down direction in Figures 3 to 5).

[0066]

[0035] The elastically deformable portions of the two legs 60a and 60b of the clip 60 have a first curved portion 61 that is convex in a first direction along the insertion direction of the connector 50 (up and down direction in Figures 3 to 5) and abuts against one of the first grooves 46a, 46b or the second groove 52, and a second curved portion 63 that is convex in a second direction opposite to the first direction and abuts against the other of the first grooves 46a, 46b or the second groove 52.

[0067]

[0036] In the example shown in Figures 3 to 6, the two legs 60a and 60b of the clip 60 have a first curved portion 61 that is convex downward along the insertion direction of the connector 5〇 (up and down direction in Figures 3 to 5), and a second curved portion 63 that is convex upward. The first curved portion 61 abuts against the lower surface of the second groove 52 of the connector 50. The second curved portion 63 abuts against the upper surface of the first grooves 46a and 46b of the backflow tube 45. On each leg 60a and 60b, the second curved portion 63 is provided in two places, flanking the first curved portion 61. The two legs 60a and 60b have a first curved portion 61 and a second curved portion 63, respectively, which allows them to be elastically deformed in the insertion direction of the connector 50.

[0068]

[0037] As shown in Figure 6, the first curved portion 61 has a shape that extends inward from the U-shape. The clip 60 has a predetermined rigidity and expands the U-shape to attach it to the backflow tube 45. As a result, the elastic force acting in the direction of returning to the original U-shape causes the two second curved portions 63 on both sides of the first curved portion 61 to engage with both ends of the first grooves 46a and 46b of the backflow tube 45, and the first curved portion 61 engages with the second groove of the connector 50.

[0069] Entering the second space 8 3 via 5 2, clip 6 ○ is fixed in place.

[0070]

[0038] Here, with reference to Figures 7 and 8, an example of a conventional configuration in which the two legs of the clip do not elastically deform in the insertion direction of the connector is described. Figure 7 is a side view corresponding to Figure 4 above, and Figure 8 is a partial cross-sectional view corresponding to Figure 5 above. The left side of Figure 8 shows the connector 50 properly positioned in the insertion hole 48 of the backflow tube 45, and the right side of Figure 8 shows the connector 50 moved relative to the backflow tube 45 in the opposite direction to the insertion direction.

[0071] [0 0 3 9] In the examples shown in Figures 7 and 8, the two legs 90a and 90b of the clip 90 are not curved in the insertion direction of the connector 5〇, and therefore are not configured to elastically deform in the insertion direction of the connector 50. Also, considering tolerances during design and workability when attaching the clip, the thickness of the clip 9〇 is made smaller than the width of the first groove 46a, 46b and the second groove 52, so that the clip 90 can swing within the first groove 46a, 46b and the second groove 52.

[0072] [0 0 4 0] As shown in Figure 8, during operation of the internal combustion engine, vibrations of the engine cause vertical vibrations 9 1 in the return pipe 2 7. In addition, the peak pressure 9 3 of the high-pressure fuel discharged from the pressure control chamber of the fuel injector generates an upward force on the connector 5 0. As a result, the connector 5 0 collides with the clip 9 0, and the clip 9 0 collides with the backflow tube 4 5, causing wear on the contact surfaces of the connector 5 0, clip 9 0, and backflow tube 4 5. If this wear progresses and the total amount of wear increases, the position of the seal ring 7 1 may shift significantly upward, potentially leading to fuel leakage (dotted arrow in Figure 8).

[0073] [0 0 4 1] In contrast, in the connector connection structure according to the first embodiment shown in Figures 3 to 6, the first curved portion 61 of the clip 6〇 abuts against the lower surface of the second groove portion 52 of the connector 5〇, and the second curved portion 63 abuts against the upper surface of the first groove portions 46a and 46b of the backflow tube 45. This suppresses rattling between the connector 50, the clip 60, and the backflow tube 45. Furthermore, the configuration in which the first curved portion 61 of the clip 60 presses the connector 50 towards the backflow tube 45 can suppress the lifting of the connector 5〇 due to vibrations that occur when the internal combustion engine is running or when a vehicle equipped with an internal combustion engine is moving.

[0074] [0 0 4 2] Furthermore, the two legs 60a and 60b of the clip 60 have a first curved portion 6I and a second curved portion 63, allowing them to be elastically deformable when the connector 50 and the backflow tube 45 move relative to each other in opposite directions. Therefore, the impact caused by the relative movement of the connector 50 and the backflow tube 45 in opposite directions during the operation of the internal combustion engine or when moving a vehicle equipped with an internal combustion engine can be mitigated.

[0075] [0 0 4 3] Furthermore, in the connector connection structure according to this embodiment, the shock-absorbing function can be maintained as long as the degree of wear of the connector 5 0, clip 6 0 and backflow tube 4 5 is small.

[0076] [0 0 4 4] In this way, according to the connector connection structure of the first embodiment, wear on the contact surfaces of the connector 5 0, clip 6 0, and backflow tube 4 5 is suppressed, and fuel leakage due to misalignment of the seal ring 7 1 can be prevented. Furthermore, according to the connector connection structure of this embodiment, the conventionally used clip can be made corrugated, and can be improved inexpensively, for example by press working.

[0077] [0 0 4 5] In the above embodiment, the first curved portion 61 of the clip 60 abutted against the lower surface of the second groove portion 52 of the connector 50, and the second curved portion 63 abutted against the upper surface of the first groove portions 46a and 46b of the backflow tube 45. However, the following modifications are also possible. That is, with the clip 60 attached to the backflow tube 45, a gap may be provided between the first curved portion 61 of the clip 60 and the lower surface of the second groove portion 52 of the connector 50, and between the second curved portion 63 and the upper surface of the first groove portions 46a and 46b of the backflow tube 45. Even with such a gap, when the connector 50 is pushed up from the backflow tube 45 due to vibrations of the internal combustion engine, the impact can be mitigated by the elastic deformation of the two legs (elastically deformable parts) 60a and 60b of the clip 60.

[0078] [0 0 4 6] In this embodiment, the second groove 52 provided in the connector 5〇 does not have to be provided around the entire circumference of the insertion portion 53. However, by providing the second groove 52 around the entire circumference of the insertion portion 53, the phase around the axis when connecting the connector 50 to the backflow tube 45 is not restricted, and the degree of freedom of the return piping 27 can be increased.

[0079] [ 0 0 4 7 ]

[0080] [Second Embodiment] In the connector connection structure according to the second embodiment, the shock mitigation structure includes a biasing means that biases the connector in the direction opposite to the fuel injection valve along the insertion direction of the connector.

[0081] [0 0 4 8] Figures 9 and 10 are explanatory diagrams showing the connection structure of a connector according to a second embodiment of the present disclosure. Figure 9 is a side view showing the connector 50 connected to the backflow tube 45. Figure 10 is a partial cross-sectional view of the IV-IV section of Figure 9, viewed in the direction of the arrow. Figure 9 is a side view corresponding to Figure 4 above, and Figure 10 is a partial cross-sectional view corresponding to Figure 5 above.

[0082] [0 0 4 9] In this embodiment, the two legs 65a and 65b of the clip 65 are not curved in the insertion direction of the connector 50, and therefore are not configured to elastically deform in the insertion direction of the connector 50. Although not shown, the planar shape of the clip 65 when viewed from the insertion direction of the connector 50 is the same U-shaped planar shape as the clip 60 shown in Figure 6.

[0083] [0 0 5 0] The connector connection structure according to this embodiment includes a coil spring 75 in the insertion hole 48 of the backflow tube 45. The coil spring 75 is held in a compressed state between the shoulder portion 49, which is the part of the insertion hole 48 where the diameter changes, and the lower end of the connector 5〇. The coil spring 75 corresponds to the biasing means in this disclosure and constitutes an impact mitigation structure.

[0084] [0 0 5 1] The coil spring 7 5 biases the connector 5 0 upward. Since a portion of the clip 6 5 is located in the second space 8 3 formed by the second groove 5 2 of the connector 5 0, the lower surface of the second groove 5 2 pushes the clip 6 5 upward. Also, since a portion of the clip 6 5 is located in the first spaces 8 1 a, 8 1 b formed by the first grooves 4 6 a, 4 6 b of the backflow tube 4 5, the clip 6 5, which has been pushed up together with the connector 5 0, comes into contact with the upper surfaces of the first grooves 4 6 a, 4 6 b, and its upward movement is restricted.

[0085] [0 0 5 2] As described above, the connector connection structure according to the second embodiment can hold the clip 6 5 and the connector 50 in a state where they are constantly pressed upward by the coil spring 7 5. Therefore, repeated collisions between the connector 50, the clip 6 5 and the backflow tube 4 5 can be prevented. As a result, wear on the contact surfaces of the connector 50, the clip 6 5 and the backflow tube 4 5 is suppressed, and fuel leakage due to displacement of the seal ring 7 1 can be prevented.

[0086] [0 0 5 3] Furthermore, according to the connector connection structure of this embodiment, the coil spring 7 5 holds the clip 6 5 and connector 5〇 in a state where they are constantly pressed upward. As a result, a biasing force is generated in the same direction as the pressure of the high-pressure fuel discharged from the pressure control chamber 3 7, which pushes the connector 5 0. Therefore, the clip 6 5 and connector 5〇 can be held in a state where they are constantly pressed upward without being affected by pressure fluctuations of the high-pressure fuel.

[0087] [0 0 5 4] Furthermore, according to the connector connection structure of this embodiment, the coil spring 7 5 holds the clip 6 5 and the connector 50 in a state where they are constantly pressed upward. This allows for greater flexibility in managing the design tolerances between the width of the first grooves 46a, 46b of the backflow tube 4 5 and the second groove 52 of the connector 50, and the thickness of the clip 6 5, thereby increasing the yield during manufacturing.

[0088] [0 0 5 5] Furthermore, in the connector connection structure according to this embodiment, the shock-absorbing function can be maintained as long as the degree of wear of the connector 5 0, clip 6 5 and backflow tube 4 5 is small.

[0089] [0 0 5 6] The biasing means for biasing the connector 5 0 upward is not limited to the coil spring 7 5, but may be any means capable of generating a biasing force. For example, the biasing means may be a leaf spring or elastic rubber.

[0090] [0 0 5 7] Although preferred embodiments of the present invention have been described in detail above with reference to the attached drawings, the present invention is not limited to such examples. It is clear to any person with ordinary skill in the art to which the present invention belongs that various modifications or alterations can be conceived within the scope of the technical idea described in the claims, and these are also understood to be within the technical scope of the present invention.

[0091] [Explanation of symbols]

[0092] [ 0 0 5 8 ]

[0093] 1: Fuel injection system

[0094] 2 7: Return piping

[0095] 3 ○: Fuel injector

[0096] 4 4 :Fuel discharge passage

[0097] 4 5: Backflow tube

[0098] 4 6 a: First groove

[0099] 4 6 b: First groove

[0100] 4 8: Insertion hole

[0101] 5 ○: Connector

[0102] 5 2: Second groove

[0103] 5 3: Insertion part

[0104] 6 0 - 6 5: Clip

[0105] 6 0 a - 6 0 b - 6 5 a - 6 5 b: Legs

[0106] 6 1: First curved section

[0107] 6 3: Second curved section

[0108] 7 1: Seal ring

[0109] 7 5: Coil spring

[0110] 8 1 a • 8 1 b: 1st space

[0111] 8 3 : 2nd space

[0112] 9 1: Vibration

[0113] 9 3: Peak pressure

Claims

[Document Name] Scope of Claim

1. A connection structure in which a connector (50) is connected to a fuel injector (30), wherein the fuel injector (30) comprises a cylindrical connecting portion (45) having an insertion hole (48) into which the connector (50) is inserted, and a first groove portion (46a, 46b) provided on the outer circumference of the connecting portion (45), the bottom of which the first groove portion (46a, 46b) penetrates the insertion hole (48), and the connector (50) comprises a cylindrical insertion portion (53) inserted into the insertion hole (48), and a second groove portion (52) provided on the outer circumference of the insertion portion (53), and the insertion portion (5 3) With the connector (50) inserted into the insertion hole (48) of the fuel injector (30), the first space (81) formed by the first groove (46a, 46b) and the second space (83) formed by the second groove (52) are connected to each other, and clips (60, 65) are locked to the connected first space (81) and second space (83) to connect the connector (50) to the fuel injector (30), and the connector has a shock-absorbing structure that mitigates the shock caused by the relative movement of the connecting part (45) and the connector (50) in opposite directions along the insertion direction of the connector (50).

2. The connector connection structure according to Claim 1, wherein the shock-absorbing structure includes elastically deformable portions (60a, 60b) provided on the clip (60) that elastically deform along the insertion direction.

3. The elastic deformation portion (60a, 60b) is such that a part of the clip (60) is convex in a first direction along the insertion direction and has a first curved portion (61) that abuts against either the first groove (46a, 46b) or the second groove (52). ) and a second curved portion of the clip (60) that is convex in a second direction opposite to the first direction and abuts against the other of either the first groove (46a, 46b) or the second groove (52). (6 3) and the connector connection structure according to claim 2.

4. The connector connection structure according to claim 1, wherein the shock mitigation structure includes a biasing means (7 5) that biases the connector (50) in the opposite direction to the fuel injector (3 0) along the insertion direction.

5. The connector (50) is a connector (50) for connecting a return pipe (27) for returning fuel discharged from the fuel injector (30) back to the fuel tank (3) to the fuel injector (30), the connector (50) according to claim 1. 9

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