Fixing structure of two components and high-pressure fuel supply pump

Abstract

The present invention makes stress generated in a fixed part of two members equal to or less than a fatigue limit without increasing the size of parts or increasing the degree of difficulty in processing. In a two-member fixing structure according to the present invention, a second member 6 includes a curved surface part 6d having one end 6a1 in a direction along a center line 1A of an outer peripheral surface 6a as a starting point 6d1. The first member 1 includes: a pressed surface 1g formed by pressing a peripheral edge part 1c2 of an inner peripheral surface 1c1; and a plastic deformation part 1x1 plastically deformed inward in the radial direction relative to the outer peripheral surface 6a of the second member 6. When a circle C1 centered on a radial outer end point 1g1 of the pressed surface 1g is drawn with a length R1 of a line segment LS1 connecting the starting point 6d1 and the radial outer end point 1g1 of the pressed surface 1g as a radius, the circle C1 intersects the curved surface part 6d. An angle θ1 between a tangent line LS2 and a line LS3 orthogonal to the center line 1A is larger than 0°, the tangent line LS2 being in contact with the curved surface part 6d at an intersection point CP between the circle C1 and the curved surface part 6d.

Description

Technical Field

[0001] The present invention relates to a fixing structure for two members and a high-pressure fuel supply pump that uses this fixing structure to pressurize fuel and supply it to an engine.

Background Art

[0002] Patent Document 1 describes a high-pressure fuel supply pump including a pump body in which a pressure chamber is formed and a cylinder that is inserted into a hole formed in the pump body and is formed in a cylindrical shape. In this high-pressure fuel supply pump, at an end portion of the pump body on the side opposite to the pressure chamber, a protruding portion is formed from the outer peripheral side to the inner peripheral side with respect to an inner peripheral surface facing the outer peripheral surface of the cylinder and protrudes toward the cylinder side. The protruding portion is formed so as to protrude to the side opposite to the pressure chamber with respect to a flat portion at the end of the pump body, and the protruding portion supports the cylinder from the side opposite to the pressure chamber (see the abstract).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, the system fuel pressure has been on an increasing trend (for example, 50 MPa or the like), and the pressure inside the pressure chamber of the high-pressure fuel pump has also been on an increasing trend. The high-pressure fuel supply pump described in Patent Document 1 has a problem that a large stress is generated at the contact portion between the protruding portion and the cylinder due to the load generated by the pressure inside this pressure chamber. Against this stress, by enlarging the support portion (fixing portion) of the cylinder, fatigue failure of the fixing portion can be prevented. However, enlarging the fixing portion leads to an increase in the size of the component and an increase in the difficulty of processing the fixing portion.

[0005] The objective of this invention is to reduce the stress generated at the fixing point between two members to a value below the fatigue limit without increasing the size of the parts or the difficulty of processing. [Means for solving the problem]

[0006] To achieve the above objective, the fixing structure of the two members of the present invention is as follows: A fixing structure for two members, which fixes a first member having a cylindrical inner surface and a second member having a cylindrical outer surface, The second member is provided with a curved surface portion at one end in the direction along the center line of the outer circumferential surface, which is a curved surface that starts from this end and decreases in diameter as it moves away from the outer circumferential surface along the center line, becoming convex radially outward. The first member comprises a pressed surface formed by pressing the peripheral edge of the inner circumferential surface of the first member while the second member is fixed to the inner circumferential surface of the first member, and a plastically deformed portion that is plastically deformed radially inward from the outer circumferential surface of the second member. When a circle is drawn with the radial outer endpoint of the pressed surface as the radius, using the length of the line segment connecting the starting point of the curved surface and the radial outer endpoint of the pressed surface of the first member as the radius, the circle intersects the curved surface. The contact initiation point where the plastically deformed portion of the first member and the second member begin to come into contact is located radially outward from the radially inward end point of the curved surface portion. At the intersection of the circle and the curved surface, the tangent line that touches the curved surface has an angle greater than 0° between it and a line perpendicular to the center line.

[0007] Furthermore, in order to achieve the above objective, the present invention High-pressure fuel supply pump teeth, A high-pressure fuel supply pump comprising a pump body and a cylinder, The pump body is designated as the first component and the cylinder as the second component, and the pump body and the cylinder are fixed together by the fixing structure of the two components described above. [Effects of the Invention]

[0008] According to the present invention, the stress generated at the contact point between the plastically deformed portion of the first member and the curved portion of the second member, i.e., the fixing portion of the two members, can be reduced to below the fatigue limit.

[0009] Other issues, configurations, and effects not mentioned above will be clarified by the following description of the embodiments. [Brief explanation of the drawing]

[0010] [Figure 1] This is an overall configuration diagram of a fuel supply system using a high-pressure fuel supply pump according to one embodiment of the present invention. [Figure 2] This is a longitudinal cross-sectional view (part 1) of a high-pressure fuel supply pump according to one embodiment of the present invention. [Figure 3] This is a longitudinal cross-sectional view (part 2) of a high-pressure fuel supply pump according to one embodiment of the present invention. [Figure 4] This is a horizontal cross-sectional view from above of a high-pressure fuel supply pump according to one embodiment of the present invention. [Figure 5] This is a longitudinal cross-sectional view (part 3) of a high-pressure fuel supply pump according to one embodiment of the present invention. [Figure 6] This is an enlarged view of the cylinder portion of a high-pressure fuel supply pump according to one embodiment of the present invention, before plastic deformation. [Figure 7] This is an enlarged view of the cylinder portion of a high-pressure fuel supply pump according to one embodiment of the present invention after plastic deformation. [Figure 8] This is an enlarged view of a protruding portion of a high-pressure fuel supply pump according to one embodiment of the present invention after plastic deformation. [Figure 9] This is a magnified view of the vicinity of the plastically deformed area in Figure 8. [Figure 10] This diagram illustrates the relationship between a circle centered on the radially outer end point of the pressed surface and the intersection point of the curved surface, according to one embodiment of the present invention. [Figure 11] This is a conceptual diagram showing a fixing structure for two members according to one embodiment of the present invention. [Modes for carrying out the invention]

[0011] 1. Embodiment Hereinafter, a high-pressure fuel supply pump according to an embodiment of the present invention will be described. In each figure, common members are denoted by the same reference numerals. Hereinafter, the high-pressure fuel supply pump may be referred to as a fuel pump for explanation.

[0012] [Fuel supply system] Next, a fuel supply system using the high-pressure fuel supply pump according to the present embodiment will be described with reference to FIG. 1.

[0013] FIG. 1 is an overall configuration diagram of a fuel supply system using the high-pressure fuel supply pump according to the present embodiment. As shown in FIG. 1, the fuel supply system includes a high-pressure fuel supply pump 100, an ECU (Engine Control Unit) 101, a fuel tank 103, a common rail 106, and a plurality of injectors 107. The components of the high-pressure fuel supply pump 100 are integrally incorporated in the pump body 1.

[0014] The fuel in the fuel tank 103 is pumped up by a feed pump 102 driven based on a signal from the ECU 101. The pumped-up fuel is pressurized to an appropriate pressure by a pressure regulator (not shown) and sent to the low-pressure fuel inlet 51 of the high-pressure fuel supply pump 100 through the low-pressure pipe 104.

[0015] The high-pressure fuel supply pump 100 pressurizes the fuel supplied from the fuel tank 103 and pumps it to the common rail 106. A plurality of injectors 107 and a fuel pressure sensor 105 are attached to the common rail 106. The plurality of injectors 107 are attached according to the number of cylinders (combustion chambers) and inject fuel according to the drive current output from the ECU 101. The fuel supply system of the present embodiment is a so-called direct injection engine system in which the injector 107 injects fuel directly into the cylinder block of the engine.

[0016] The fuel pressure sensor 105 outputs the detected pressure data to the ECU 101. The ECU 101 calculates the appropriate fuel injection amount (target fuel injection length) and appropriate fuel pressure (target fuel pressure) based on engine state variables obtained from various sensors (e.g., crank rotation angle, throttle opening, engine speed, fuel pressure, etc.).

[0017] Furthermore, the ECU 101 controls the operation of the high-pressure fuel supply pump 100 and the multiple injectors 107 based on calculation results such as fuel pressure (target fuel pressure). In other words, the ECU 101 has a pump control unit that controls the high-pressure fuel supply pump 100 and an injector control unit that controls the injectors 107.

[0018] The high-pressure fuel supply pump 100 includes a pressure pulsation reduction mechanism 9, a variable-capacity electromagnetic intake valve 3, a relief valve 4 (see Figure 2), and a discharge valve 8. Fuel flowing in from the low-pressure fuel inlet 51 reaches the intake port 31b of the electromagnetic intake valve 3 via the pressure pulsation reduction mechanism 9 and the intake passage 10b.

[0019] Fuel flowing into the electromagnetic intake valve 3 passes through the valve section 32, flows through the intake passage 1d formed in the pump body 1, and then flows into the pressurizing chamber 11. A plunger 2 is inserted into the pressurizing chamber 11 so as to be able to reciprocate. The plunger 2 reciprocates when power is transmitted from the engine's cam 91 (see Figure 2).

[0020] In the pressurized chamber 11, fuel is drawn in from the electromagnetic intake valve 3 during the downward stroke of the plunger 2, and the fuel is pressurized during the upward stroke. When the fuel pressure in the pressurized chamber 11 exceeds a predetermined value, the discharge valve 8 opens, and high-pressure fuel is pumped to the common rail 106 via the discharge passage 12a. The discharge of fuel by the high-pressure fuel supply pump 100 is operated by opening and closing the electromagnetic intake valve 3. The opening and closing of the electromagnetic intake valve 3 is controlled by the ECU 101.

[0021] [High-pressure fuel supply pump] Next, the configuration of the high-pressure fuel supply pump 100 will be explained using Figures 2 to 5. Figure 2 is a longitudinal cross-sectional view (1) of the high-pressure fuel supply pump 100, viewed in a cross-section perpendicular to the horizontal direction. Figure 3 is a longitudinal cross-sectional view (2) of the high-pressure fuel supply pump 100, viewed in a cross-section perpendicular to the horizontal direction. Figure 4 is a horizontal cross-sectional view of the high-pressure fuel supply pump 100, viewed in a cross-section perpendicular to the vertical direction. Figure 5 is a longitudinal cross-sectional view (3) of the high-pressure fuel supply pump 100, viewed in a cross-section perpendicular to the horizontal direction.

[0022] As shown in Figures 2 to 5, the pump body 1 of the high-pressure fuel supply pump 100 is formed in a substantially cylindrical shape. As shown in Figures 2 and 3, the pump body 1 is provided with a first chamber 1a, a second chamber 1b, a third chamber 1c, and an intake passage 1d inside. The pump body 1 is in close contact with the fuel pump mounting portion 90 and is fixed with a number of bolts (screws) not shown.

[0023] The first chamber 1a is a cylindrical space provided in the pump body 1, and the centerline 1A of the first chamber 1a coincides with the centerline of the pump body 1. One end of the plunger 2 is inserted into this first chamber 1a, and the plunger 2 reciprocates within the first chamber 1a. The first chamber 1a and the one end of the plunger 2 form a pressurized chamber 11.

[0024] The second chamber 1b is a cylindrical space provided in the pump body 1, and the centerline of the second chamber 1b is perpendicular to the centerline of the pump body 1 (first chamber 1a). A relief valve 4 is located in this second chamber 1b. The diameter of the second chamber 1b is smaller than the diameter of the first chamber 1a.

[0025] Furthermore, the first chamber 1a and the second chamber 1b are connected by a circular connecting hole 1e. The diameter of the connecting hole 1e is the same as the diameter of the first chamber 1a, and the connecting hole 1e extends one end of the first chamber 1a. The diameter of the connecting hole 1e is larger than the outer diameter of the plunger 2. The centerline of the connecting hole 1e is perpendicular to the centerline of the second chamber 1b.

[0026] As shown in Figures 3 and 5, the diameter of the communication hole 1e is larger than the diameter of the second chamber 1b. This allows the fuel that has passed through the relief valve 4 located in the second chamber 1b to return smoothly to the pressurized chamber 11.

[0027] The third chamber 1c is a cylindrical space provided in the pump body 1 and is continuous with the other end of the first chamber 1a. The centerline of the third chamber 1c coincides with the centerline 1A of the first chamber 1a and the centerline of the pump body 1, and the diameter of the third chamber 1c is larger than the diameter of the first chamber 1a. A cylinder 6 that guides the reciprocating motion of the plunger 2 is located in this third chamber 1c.

[0028] This will be explained using Figures 6 and 7. Figure 6 is an enlarged view of the cylinder portion of a high-pressure fuel supply pump 100 according to one embodiment of the present invention before plastic deformation. Figure 7 is an enlarged view of the cylinder portion of a high-pressure fuel supply pump 100 according to one embodiment of the present invention after plastic deformation.

[0029] The cylinder 6 is formed in a cylindrical shape, and its inner circumferential surface 6e is cylindrical. A plunger 2 having a cylindrical outer circumferential surface 2c is inserted into this inner circumferential surface 6e. The cylinder 6 has a cylindrical outer circumferential surface 6a that serves as a press-fit portion, and a surface (radial surface) 6f that runs along the radial direction. The cylinder 6 has a smaller diameter portion 6g than the outer circumferential surface 6a, and the radial surface 6f is provided between the outer circumferential surface 6a and the smaller diameter portion 6g, connecting the outer circumferential surface 6a and the smaller diameter portion 6g.

[0030] The cylinder 6 is press-fitted into the third chamber 1c of the pump body 1 at its outer circumference via a press-fit portion 6a, and one end of the cylinder 6 abuts against the top surface of the third chamber 1c (the stepped portion between the first chamber 1a and the third chamber 1c) 1f. Only the press-fit portion 6a of the cylinder is press-fitted, and the diameter φ6c on the press-fit portion 6a side of the pressurizing chamber 11 is set to be smaller than the diameter φ6a of the press-fit portion 6a. Therefore, a clearance exists between the cylinder and the third chamber 1c. The plunger 2 is in slidable contact with the inner circumferential surface of the cylinder 6.

[0031] Figure 6 shows the state immediately after the cylinder 6 is press-fitted into the third chamber 1c. One end of the cylinder 6 is in contact with the top surface of the third chamber 1c. In this state, a load of several hundred kN is applied to the pressing part 1y, deforming the protruding part 1x. Figure 7 shows the shape of the protruding part 1x after deformation. The protruding part 1x deforms so as to overlap the cylinder corner 6b due to the load from the pressing part 1y. That is, a plastically deformed portion 1x1 is formed on the protruding part 1x, and the cylinder 6 is prevented from falling out of the third chamber 1c by the press-fit portion 6a and the plastically deformed portion 1x1 of the protruding part 1x.

[0032] Here, the cylinder corner 6b has an R shape. Alternatively, the cylinder corner 6b may be set to a shape that smoothly connects the press-fit portion (outer surface) 6a and the radial surface 6f, so that there are no discontinuities in the area that contacts the protruding portion 1x, rather than having an R shape. As will be described in detail later, this is to keep the stress generated in the protruding portion below the fatigue limit when the pressurizing chamber 11 becomes high pressure and a pull-out load is generated in the cylinder 6.

[0033] Let's return to Figures 2 to 5 for further explanation. Between the fuel pump mounting section 90 and the pump body 1, there is an O-ring 93, which is a specific example of a seat material. This O-ring 93 prevents engine oil from leaking outside the engine (internal combustion engine) through the space between the fuel pump mounting section 90 and the pump body 1.

[0034] At the lower end of the plunger 2 is a tappet 92 that converts the rotational motion of the cam 91 attached to the engine's camshaft into vertical motion and transmits it to the plunger 2. The plunger 2 is biased toward the cam 91 by a spring 16 via a retainer 15 and is pressed against the tappet 92. The tappet 92 reciprocates in accordance with the rotation of the cam 91. The plunger 2 reciprocates together with the tappet 92, changing the volume of the pressurizing chamber 11.

[0035] Furthermore, a seal holder 17 is positioned between the cylinder 6 and the retainer 15. The seal holder 17 is formed in a cylindrical shape into which the plunger 2 is inserted, and has a sub-chamber 17a at its upper end, which is on the cylinder 6 side. The seal holder 17 also holds a plunger seal 18 at its lower end, which is on the retainer 15 side.

[0036] The plunger seal 18 is in slidable contact with the outer circumference of the plunger 2. When the plunger 2 reciprocates, the plunger seal 18 seals the fuel in the sub-chamber 17a. This prevents the fuel in the sub-chamber 17a from flowing into the engine. The plunger seal 18 also prevents lubricating oil (including engine oil) that lubricates the sliding parts inside the engine from flowing into the pump body 1.

[0037] In Figure 2, the plunger 2 reciprocates in the vertical direction. When the plunger 2 descends, the volume of the pressurized chamber 11 expands, and when the plunger 2 rises, the volume of the pressurized chamber 11 decreases. In other words, the plunger 2 is arranged to reciprocate in a direction that expands and contracts the volume of the pressurized chamber 11.

[0038] The plunger 2 has a large diameter section 2a and a small diameter section 2b. When the plunger 2 reciprocates, the large diameter section 2a and the small diameter section 2b are located in the sub-chamber 17a. Therefore, the volume of the sub-chamber 17a increases or decreases with the reciprocating motion of the plunger 2.

[0039] The sub-chamber 17a is in communication with the low-pressure fuel chamber 10 via the fuel passage 10c (see Figure 5). When the plunger 2 descends, fuel flows from the sub-chamber 17a to the low-pressure fuel chamber 10, and when the plunger 2 rises, fuel flows from the low-pressure fuel chamber 10 to the sub-chamber 17a. This reduces the fuel flow rate into and out of the pump during the intake or return stroke of the high-pressure fuel supply pump 100. This reduces pressure pulsation generated inside the high-pressure fuel supply pump 100.

[0040] As shown in Figure 3, a low-pressure fuel chamber 10 is provided at the top of the pump body 1 of the high-pressure fuel supply pump 100, and an intake joint 5 is attached to the side of the pump body 1. The intake joint 5 is connected to a low-pressure pipe 104 through which fuel supplied from the fuel tank 103 (see Figure 1) passes. Fuel from the fuel tank 103 is supplied to the inside of the pump body 1 from the intake joint 5.

[0041] The intake joint 5 has a low-pressure fuel inlet 51 connected to the low-pressure piping 104 and an intake passage 52 communicating with the low-pressure fuel inlet 51. Fuel that has passed through the intake passage 52 is supplied to the low-pressure fuel chamber 10 after passing through an intake filter 53 provided inside the pump body 1. The intake filter 53 removes foreign matter present in the fuel and prevents foreign matter from entering the high-pressure fuel supply pump 100.

[0042] The low-pressure fuel chamber 10 is provided with a low-pressure fuel passage 10a and an intake passage 10b (see Figure 2). A pressure pulsation reduction mechanism 9 is provided in the low-pressure fuel passage 10a. When fuel that has flowed into the pressurized chamber 11 is returned to the intake passage 10b through the open electromagnetic intake valve 3, pressure pulsations occur in the low-pressure fuel chamber 10. The pressure pulsation reduction mechanism 9 reduces the propagation of pressure pulsations generated in the high-pressure fuel supply pump 100 to the low-pressure piping 104.

[0043] The pressure pulsation reduction mechanism 9 is formed from a metal diaphragm damper, which consists of two corrugated disc-shaped metal plates joined together at their outer circumferences, with an inert gas such as argon injected into its interior. The metal diaphragm damper of the pressure pulsation reduction mechanism 9 absorbs or reduces pressure pulsations by expanding and contracting.

[0044] The intake passage 10b is connected to the intake port 31b of the electromagnetic intake valve 3 (see Figure 2), and the fuel that has passed through the low-pressure fuel passage 10a reaches the intake port 31b of the electromagnetic intake valve 3 via the intake passage 10b.

[0045] As shown in Figures 2 and 4, the electromagnetic suction valve 3 is inserted into a lateral hole formed in the pump body 1. The electromagnetic suction valve 3 includes a suction valve seat 31 pressed into the lateral hole formed in the pump body 1, a valve portion 32, a rod 33, a rod biasing spring 34, an electromagnetic coil 35, and an anchor 36.

[0046] The intake valve seat 31 is formed in a cylindrical shape, and a seating portion 31a is provided on its inner circumference. The intake valve seat 31 also has an intake port 31b that extends from the outer circumference to the inner circumference. This intake port 31b communicates with the intake passage 10b in the low-pressure fuel chamber 10 described above.

[0047] A stopper 37 is positioned in a lateral hole formed in the pump body 1, facing the seating portion 31a of the suction valve seat 31, and a valve portion 32 is positioned between the stopper 37 and the seating portion 31a. A valve biasing spring 38 is interposed between the stopper 37 and the valve portion 32. The valve biasing spring 38 biases the valve portion 32 toward the seating portion 31a.

[0048] The valve portion 32, by contacting the seat portion 31a, closes the communication between the intake port 31b and the pressurizing chamber 11, causing the electromagnetic intake valve 3 to be in a closed state. On the other hand, the valve portion 32, by contacting the stopper 37, opens the communication between the intake port 31b and the pressurizing chamber 11, causing the electromagnetic intake valve 3 to be in an open state.

[0049] The rod 33 passes through the cylindrical hole of the intake valve seat 31, with one end in contact with the valve portion 32. The rod biasing spring 34 biases the valve portion 32 in the opening direction, towards the stopper 37, via the rod 33. One end of the rod biasing spring 34 engages with the other end of the rod 33, and the other end of the rod biasing spring 34 engages with a magnetic core 39 that is positioned to surround the rod biasing spring 34.

[0050] The anchor 36 faces the end face of the magnetic core 39. The anchor 36 is also engaged with a flange provided in the middle of the rod 33. The electromagnetic coil 35 is arranged to encircle the magnetic core 39. A terminal member 40 is electrically connected to the electromagnetic coil 35, and current flows through the terminal member 40.

[0051] In the unpowered state, when no current flows through the electromagnetic coil 35, the rod 33 is biased in the valve-opening direction by the biasing force of the rod biasing spring 34, pressing the valve portion 32 in the valve-opening direction. As a result, the valve portion 32 separates from the seat portion 31a and contacts the stopper 37, and the electromagnetic intake valve 3 is in the open state. In other words, the electromagnetic intake valve 3 is a normally open type that opens in the unpowered state.

[0052] When the electromagnetic intake valve 3 is open, fuel from the intake port 31b flows through the space between the valve portion 32 and the seat portion 31a, and into the pressurized chamber 11 through multiple fuel passage holes (not shown) in the stopper 37 and the intake passage 1d. When the electromagnetic intake valve 3 is open, the valve portion 32 is in contact with the stopper 37, thus restricting the position of the valve portion 32 in the opening direction. The gap between the valve portion 32 and the seat portion 31a when the electromagnetic intake valve 3 is open is the range of motion of the valve portion 32, and this is the opening stroke.

[0053] When current flows through the electromagnetic coil 35, the anchor 36 is attracted in the valve-closing direction by the magnetic attraction of the magnetic core 39. As a result, the anchor 36 moves against the biasing force of the rod biasing spring 34 and comes into contact with the magnetic core 39. When the anchor 36 moves in the valve-closing direction toward the magnetic core 39, the rod 33 with which the anchor 36 engages moves together with the anchor 36. As a result, the valve portion 32 is released from the biasing force toward the valve-opening direction and moves in the valve-closing direction due to the biasing force of the valve biasing spring 38. When the valve portion 32 comes into contact with the seating portion 31a of the suction valve seat 31, the electromagnetic suction valve 3 enters the closed state.

[0054] As shown in Figures 4 and 5, the discharge valve 8 is connected to the outlet side (downstream side) of the pressurizing chamber 11. The discharge valve 8 includes a discharge valve seat 81 that communicates with the pressurizing chamber 11, a valve portion 82 that moves toward and away from the discharge valve seat 81, a discharge valve spring 83 that biases the valve portion 82 toward the discharge valve seat 81, and a discharge valve stopper 84 that determines the stroke (travel distance) of the valve portion 82.

[0055] Furthermore, the discharge valve 8 has a plug 85 that blocks fuel leakage to the outside. The discharge valve stopper 84 is press-fitted into the plug 85. The plug 85 is joined to the pump body 1 by welding at a weld 86. The discharge valve 8 is in communication with a discharge valve chamber 87, which is opened and closed by a valve section 82. The discharge valve chamber 87 is formed in the pump body 1.

[0056] The pump body 1 is provided with a lateral hole that communicates with the second chamber 1b (see Figure 2), and a discharge joint 12 is inserted into this lateral hole. The discharge joint 12 has the aforementioned discharge passage 12a that communicates with the lateral hole of the pump body 1 and the discharge valve chamber 87, and a fuel outlet 12b which is one end of the discharge passage 12a. The fuel outlet 12b of the discharge joint 12 communicates with the common rail 106. The discharge joint 12 is fixed to the pump body 1 by welding at a welded joint 12c.

[0057] When there is no fuel pressure difference (fuel differential pressure) between the pressurizing chamber 11 and the discharge valve chamber 87, the valve portion 82 is pressed against the discharge valve seat 81 by the biasing force of the discharge valve spring 83, and the discharge valve 8 is in a closed state. When the fuel pressure in the pressurizing chamber 11 becomes greater than the fuel pressure in the discharge valve chamber 87, the valve portion 82 moves against the biasing force of the discharge valve spring 83, and the discharge valve 8 opens.

[0058] When the discharge valve 8 is closed, the (high-pressure) fuel in the pressurizing chamber 11 passes through the discharge valve 8 and reaches the discharge valve chamber 87. The fuel that reaches the discharge valve chamber 87 is then discharged to the common rail 106 (see Figure 1) via the fuel discharge port 12b of the discharge joint 12. With this configuration, the discharge valve 8 functions as a check valve that restricts the direction of fuel flow.

[0059] The relief valve 4 shown in Figure 2 is configured to operate when a problem occurs in the common rail 106 or the components beyond it, causing the common rail 106 to exceed a predetermined pressure and return the fuel in the discharge passage 12a to the pressurizing chamber 11. This relief valve 4 is positioned higher than the discharge valve 8 (see Figure 5) in the direction of the reciprocating motion of the plunger 2 (vertical direction).

[0060] The relief valve 4 comprises a relief spring 41, a relief valve holder 42, a valve section 43, and a seat member 44. This relief valve 4 is inserted from the discharge joint 12 and positioned in the second chamber 1b. One end of the relief spring 41 abuts against the pump body 1 (one end of the second chamber 1b), and the other end abuts against the relief valve holder 42. The relief valve holder 42 engages with the valve section 43, and the biasing force of the relief spring 41 acts on the valve section 43 via the relief valve holder 42.

[0061] The valve portion 43 is pressed by the biasing force of the relief spring 41, blocking the fuel passage of the seat member 44. The direction of movement of the valve portion 43 (relief valve holder 42) is perpendicular to the direction in which the plunger 2 reciprocates. Furthermore, the centerline of the relief valve 4 (centerline of the relief valve holder 42) is perpendicular to the centerline of the plunger 2.

[0062] The seat member 44 has a fuel passage facing the valve portion 43, and the side of the fuel passage opposite the valve portion 43 is in communication with the discharge passage 12a. The movement of fuel between the pressurizing chamber 11 (upstream side) and the seat member 44 (downstream side) is blocked when the valve portion 43 contacts (closely seals) the seat member 44 and blocks the fuel passage.

[0063] When the pressure in the common rail 106 or the components beyond it increases, the fuel on the seat member 44 side presses against the valve 43, causing it to move against the biasing force of the relief spring 41. As a result, the valve 43 opens, and the fuel in the discharge passage 12a returns to the pressurized chamber 11 through the fuel passage of the seat member 44. Therefore, the pressure required to open the valve 43 is determined by the biasing force of the relief spring 41.

[0064] The direction of movement of the valve portion 43 (relief valve holder 42) in the relief valve 4 is different from the direction of movement of the valve portion 82 in the discharge valve 8 described above. That is, the direction of movement of the valve portion 82 in the discharge valve 8 is the first radial direction of the pump body 1, while the direction of movement of the valve portion 43 in the relief valve 4 is the second radial direction, which is different from the first radial direction of the pump body 1. As a result, the discharge valve 8 and the relief valve 4 can be positioned so that they do not overlap each other in the vertical direction, and the space inside the pump body 1 can be effectively utilized to make the pump body 1 smaller.

[0065] [Operation of the high-pressure fuel supply pump] Next, the operation of the high-pressure fuel supply pump according to this embodiment will be explained using Figures 2 and 4. In Figure 2, when the plunger 2 descends and the electromagnetic intake valve 3 is open, fuel flows from the intake passage 1d into the pressurizing chamber 11. Hereinafter, the stroke in which the plunger 2 descends will be referred to as the intake stroke. On the other hand, when the plunger 2 rises and the electromagnetic intake valve 3 is closed, the fuel in the pressurizing chamber 11 is pressurized and pumped through the discharge valve 8 to the common rail 106 (see Figure 1). Hereinafter, the stroke in which the plunger 2 rises will be referred to as the rising stroke.

[0066] As described above, if the electromagnetic intake valve 3 is closed during the upward stroke, the fuel drawn into the pressurizing chamber 11 during the intake stroke is pressurized and discharged to the common rail 106 side. On the other hand, if the electromagnetic intake valve 3 is open during the upward stroke, the fuel in the pressurizing chamber 11 is pushed back to the intake passage 1d side and is not discharged to the common rail 106 side. Thus, the discharge of fuel by the high-pressure fuel supply pump 100 is operated by opening and closing the electromagnetic intake valve 3. The opening and closing of the electromagnetic intake valve 3 is controlled by the ECU 101.

[0067] During the intake stroke, the volume of the pressurized chamber 11 increases, and the fuel pressure inside the pressurized chamber 11 decreases. This reduces the fluid pressure difference between the intake port 31b and the pressurized chamber 11 (hereinafter referred to as the "fluid pressure difference before and after the valve portion 32"). When the biasing force of the rod biasing spring 34 becomes greater than the fluid pressure difference before and after the valve portion 32, the rod 33 moves in the valve opening direction, the valve portion 32 separates from the seat portion 31a of the intake valve seat 31, and the electromagnetic intake valve 3 opens.

[0068] When the electromagnetic intake valve 3 is open, fuel from the intake port 31b flows through the gap between the valve portion 32 and the seat portion 31a, and through multiple fuel passage holes (not shown) in the stopper 37 into the pressurized chamber 11. When the electromagnetic intake valve 3 is open, the valve portion 32 is in contact with the stopper 37, thus restricting the position of the valve portion 32 in the opening direction. The gap between the valve portion 32 and the seat portion 31a when the electromagnetic intake valve 3 is open is the range of motion of the valve portion 32, and this is the opening stroke.

[0069] After the intake stroke is completed, the system moves to the upward stroke. At this time, the electromagnetic coil 35 remains unenergized, and no magnetic attraction force acts between the anchor 36 and the magnetic core 39. The valve section 32 is subjected to a biasing force in the opening direction corresponding to the difference in biasing forces between the rod biasing spring 34 and the valve biasing spring 38, and a force pressing in the closing direction due to the fluid force generated when fuel flows back from the pressurized chamber 11 to the low-pressure fuel passage 10a.

[0070] In this state, in order for the electromagnetic intake valve 3 to maintain the open state, the difference in biasing force between the rod biasing spring 34 and the valve biasing spring 38 is set to be greater than the fluid force. The volume of the pressurizing chamber 11 decreases as the plunger 2 rises. Therefore, the fuel that was drawn into the pressurizing chamber 11 is returned to the intake port 31b by passing again between the valve section 32 and the seating section 31a. As a result, the pressure inside the pressurizing chamber 11 does not rise. This process is called the return process.

[0071] During the return process, when a control signal from the ECU 101 (see Figure 1) is applied to the electromagnetic intake valve 3, current flows through the electromagnetic coil 35 via the terminal member 40. When current flows through the electromagnetic coil 35, a magnetic attractive force acts between the magnetic core 39 and the anchor 36, causing the anchor 36 (rod 33) to be attracted to the magnetic core 39. As a result, the anchor 36 (rod 33) moves in the valve closing direction (away from the valve portion 32) against the biasing force of the rod biasing spring 34.

[0072] When the anchor 36 (rod 33) moves in the valve closing direction, the valve portion 32 is released from the biasing force in the valve opening direction and moves in the valve closing direction due to the biasing force of the valve biasing spring 38 and the fluid force caused by the fuel flowing into the intake passage 10b. When the valve portion 32 comes into contact with the seat portion 31a of the intake valve seat 31 (the valve portion 32 seats on the seat portion 31a), the electromagnetic intake valve 3 becomes closed.

[0073] After the electromagnetic intake valve 3 closes, the fuel in the pressurizing chamber 11 is pressurized as the plunger 2 rises, and when it reaches a predetermined pressure or higher, it is discharged through the discharge valve 8 to the common rail 106 (see Figure 1). This process is called the discharge process. In other words, the upward process from the lower starting point to the upper starting point of the plunger 2 consists of a return process and a discharge process. The amount of high-pressure fuel discharged can be controlled by controlling the timing of energization to the electromagnetic coil 35 of the electromagnetic intake valve 3.

[0074] If the timing of energizing the electromagnetic coil 35 is advanced, the proportion of the return stroke during the upward stroke decreases, and the proportion of the discharge stroke increases. As a result, less fuel is returned to the intake passage 10b, and more fuel is discharged at high pressure. On the other hand, if the timing of energizing the electromagnetic coil 35 is delayed, the proportion of the return stroke during the upward stroke increases, and the proportion of the discharge stroke decreases. As a result, more fuel is returned to the intake passage 10b, and less fuel is discharged at high pressure. In this way, by controlling the timing of energizing the electromagnetic coil 35, the amount of fuel discharged at high pressure can be controlled to the amount required by the engine (internal combustion engine).

[0075] 2. Summary As described above, the high-pressure fuel supply pump 100 according to the above embodiment comprises a pump body 1, a plunger 2, an electromagnetic intake valve 3, and a relief valve 4. The plunger 2 reciprocates within a cylindrical space in the pump body 1, which is a first chamber 1a. The electromagnetic intake valve 3 draws fuel into the pressurized chamber 11 formed by the first chamber 1a and the plunger 2. The relief valve 4 opens when the fuel pressure downstream of the pressurized chamber 11 exceeds a set value, returning fuel to the pressurized chamber 11. The pump body 1 has a second chamber 1b where the relief valve 4 is located, and a communication hole 1e connecting the first chamber 1a and the second chamber 1b. The diameter of the communication hole 1e is the same as the diameter of the first chamber 1a.

[0076] When machining holes such as the first chamber 1a, the second chamber 1b, and the communication hole 1e in the pump body 1, unnecessary protrusions (burrs) are generated on the machined surface. If these protrusions (burrs) are left as they are, errors will occur in the dimensions of the holes, making it impossible to install parts or causing injuries if touched. Therefore, it is necessary to remove the protrusions (burrs). In the embodiment described above, since the diameter of the communication hole 1e is the same as the diameter of the first chamber 1a, machining of the communication hole 1e becomes easy, and the removal of protrusions (burrs) can be easily performed. In addition, the shape of the pump body 1 can be kept from becoming complicated. Therefore, the productivity of the pump body 1 and the high-pressure fuel supply pump 100 can be improved, and costs can be reduced.

[0077] Furthermore, since the diameter of the communication hole 1e is the same as the diameter of the first chamber 1a, fuel flows more easily from the relief valve 4 to the pressurizing chamber 11, improving the relief performance. In addition, since the relief valve is directly incorporated into the second chamber 1b provided in the pump body 1, the housing (seat member) that houses the components of the relief valve can be omitted, reducing the number of parts and thus reducing costs.

[0078] Furthermore, in the high-pressure fuel supply pump 100 according to the above embodiment, the second chamber 1b (second chamber) is a cylindrical space, and the diameter of the second chamber 1b is smaller than the diameter of the communication hole 1e (communication hole). This makes it easier for the fuel flowing from the relief valve 4 to the pressurizing chamber 11 to pass through the communication hole 1e, thereby improving the relief performance.

[0079] Furthermore, in the high-pressure fuel supply pump 100 according to the above-described embodiment, the center line of the communication hole 1e (communication hole) is perpendicular to the center line of the second chamber 1b (second chamber). This allows fuel that has passed through the relief valve 4 located in the second chamber 1b to be efficiently passed through the communication hole 1e, without hindering the improvement of relief performance. In addition, the shape of the pump body 1 can be kept simple, thereby improving the productivity of the pump body 1 and the high-pressure fuel supply pump 100.

[0080] Furthermore, in the high-pressure fuel supply pump 100 according to the above embodiment, the diameter of the communication hole 1e (communication hole) is larger than the outer diameter of the plunger 2 (plunger). As a result, the plunger 2, which reciprocates in the pressurizing chamber 11, does not collide with the area around the communication hole 1e, thereby improving the durability of the plunger 2.

[0081] Furthermore, the high-pressure fuel supply pump 100 according to the above embodiment includes a discharge joint 12 attached to the pump body 1 downstream of the pressurizing chamber 11 (pressurizing chamber). The relief valve 4 is inserted into the second chamber 1b from the discharge joint 12. This allows the relief valve 4 to be easily placed in the second chamber 1b, improving the workability of the assembly of the high-pressure fuel supply pump 100. In addition, there is no need to newly provide a hole in the pump body 1 to make the relief valve 4 into the second chamber 1b, thus keeping the shape of the pump body 1 from becoming complicated.

[0082] Furthermore, in the high-pressure fuel supply pump 100 according to the above embodiment, the direction of movement of the valve portion 43 in the relief valve 4 is perpendicular to the direction in which the plunger 2 reciprocates. This prevents the second chamber 1b for arranging the relief valve 4 from extending in the direction in which the plunger 2 reciprocates. As a result, the length of the pump body 1 in the direction in which the plunger 2 reciprocates can be shortened, thereby making the pump body 1 more compact.

[0083] Furthermore, the high-pressure fuel supply pump 100 according to the above embodiment includes a discharge valve 8 located downstream of the pressurizing chamber 11. The direction of movement of the valve portion 82 in the discharge valve 8 is different from the direction of movement of the valve portion 43 in the relief valve 4. The relief valve 4 is positioned higher than the discharge valve 8 in the vertical direction, which is the direction in which the plunger 2 reciprocates. This prevents interference between the discharge valve 8 and the relief valve 4, even if parts of them overlap in a direction perpendicular to the vertical direction. This allows for effective use of the space inside the pump body 1, thereby enabling miniaturization of the pump body 1.

[0084] Furthermore, the pump body 1 of the high-pressure fuel supply pump 100 according to the above embodiment is formed in a substantially cylindrical shape, and the center of the first chamber 1a coincides with the center of the pump body 1. The direction of movement of the valve portion 82 in the discharge valve 8 is the first radial direction of the pump body 1. Also, the direction of movement of the valve portion 43 in the relief valve 4 is a second radial direction different from the first radial direction of the pump body 1. As a result, the discharge valve 8 and the relief valve 4 can be positioned so that they do not overlap with each other in the direction of movement of the plunger 2, and the internal space of the pump body 1 can be effectively utilized to reduce the size of the pump body 1.

[0085] The pump body 1 of the high-pressure fuel supply pump 100 according to the above-described embodiment has a third chamber 1c that communicates with the first chamber 1a and has a larger diameter than the first chamber 1a. A cylinder 6 is arranged in the third chamber 1c through which a plunger 2 slides. This allows the end face of the cylinder 6 to abut against the stepped portion between the first chamber 1a and the third chamber 1c, preventing the cylinder 6 from shifting towards the first chamber 1a. The fuel, which has become high-pressure in the pressurizing chamber 11, is prevented from leaking to the low-pressure side by the contact surface pressure between the press-fit portion (press-fit surface) 6a or the corner portion 6b of the cylinder 6 and the third chamber 1c.

[0086] When the high-pressure fuel supply pump 100 operates and the pressure inside the pressurizing chamber 11 becomes high, the same pressure as inside the pressurizing chamber 11 is also applied to the end face of the cylinder 6. This pressure generates a force on the cylinder 6 that pulls it out of the third chamber 1c. This pull-out force is absorbed by the press-fit portion 6a and the protruding portion 1x having a plastically deformable portion 1x1, preventing the cylinder 6 from falling out. However, if the fuel pressure is further increased, the stress generated in the protruding portion 1x becomes excessive, potentially causing fatigue failure of the protruding portion 1x.

[0087] Therefore, in this embodiment, as shown in Figure 7, the pump body 1 has a shape having a protrusion 1x and a plastically deformable portion 1x1 around the entire circumference of the center line (axis) of the cylinder 6. In this case, the protrusion 1x and the plastically deformable portion 1x1 are axially symmetric. Furthermore, the cylinder corner portion 6 bThe R-shape was set to be R0.3 to R0.5. However, this is not necessarily the only option, and other values ​​may be set depending on the situation. Also, the cylinder corner 6 b The radial surface 6f of the cylinder 6 may be smoothly connected to the radial surface 6f, which is aligned with the radial direction of the cylinder 6, and the press-fit portion 6a, so that there are no discontinuities in the region that contacts the protruding portion 1x. This makes it possible to suppress the concentration of stress at a single point in the protruding portion 1x which has a plastically deformed portion 1x1. Note that the radial surface 6f is not limited to being perpendicular to the center line 1A, but may have an inclination with respect to the direction perpendicular to the center line 1A.

[0088] The high-pressure fuel supply pump 100 of this embodiment has a two-member fixing structure that suppresses stress concentration. This two-member fixing structure will be explained with reference to Figure 8. Figure 8 is an enlarged view of the protrusion 1x of a high-pressure fuel supply pump 100 according to one embodiment of the present invention after plastic deformation. Figure 8 is a cross-section that includes the center line 1A and is parallel to the center line 1A.

[0089] In this embodiment, the shape of the cylinder corner portion 6, which smoothly connects the radial surface 6f of the cylinder 6 and the press-fit portion 6a, is described as a curved surface portion that includes an R shape and is convex radially outward.

[0090] The fixing structure applied to the high-pressure fuel supply pump 100 of this embodiment is a two-member fixing structure that fixes a first member (pump body) 1 having a cylindrical inner circumferential surface 1c1 and a second member (cylinder) 6 having a cylindrical outer circumferential surface 6a. The second member (cylinder) 6 has a curved surface portion 6d at one end 6a1 in the direction along the center line 1A of the outer circumferential surface 6a (axial direction), with this end as the starting point 6d1, and the diameter decreasing so as it moves away from the outer circumferential surface 6a along the center line 1A, becoming convex radially outward. The first member (pump body) 1 has a pressed surface 1g formed by pressing the peripheral edge 1c2 of the inner circumferential surface 1c1 of the first member (pump body) 1 while the second member (cylinder) 6 is fixed to the inner circumferential surface 1c1 of the first member (pump body) 1, and a plastically deformed portion 1x1 that is plastically deformed radially inward from the outer circumferential surface 6a of the second member (cylinder) 6.

[0091] Here, using Figure 9, we will explain the characteristics of the pressed surface 1g that is pressed by the punch. Figure 9 is an enlarged view of the vicinity of the plastically deformed portion 1x1 in Figure 8. Figure 9 is a cross-section that includes the center line 1A and is parallel to the center line 1A.

[0092] When a circle C1 is drawn with the radial outer endpoint 1g1 of the pressed surface 1g as the radius, using the length R1 of the line segment LS1 connecting the starting point 6d1 of the curved surface 6d and the radial outer endpoint 1g1 of the pressed surface 1g of the first member (pump body) 1, the circle C1 intersects with the curved surface 6d. Then, the tangent line LS2 that is tangent to the curved surface 6d at the intersection point CP of circle C1 and the curved surface 6d has an angle θ1 greater than 0° between it and the line (line segment) LS3 that is perpendicular to the center line 1A.

[0093] The radial outer endpoint of the curved surface 6d is 6d1, and the radial inner endpoint of the curved surface 6d is 6d2. That is, the curved surface 6d is formed between 6d1 and 6d2. The R-shaped section with radius R2 is formed within a range of a central angle of 90°, the line segment LS4 connecting the center Or of the R-shaped section and 6d1 is perpendicular to the center line 1A (see Figure 8), and the line segment LS5 connecting the center Or of the R-shaped section and 6d2 is parallel to the center line 1A.

[0094] Let 6d3 be the point where the protrusion 1x of the pump body 1 and the cylinder corner 6b begin to make contact. The contact point 6d3 is the innermost (innermost circumference) part in the radial direction within the region where the protrusion 1x and the cylinder corner 6b make contact. The curved surface (R part) 6d is in contact with the protrusion 1x in the entire region on the pressurizing chamber 11 side of the contact point 6d3, and there is no gap. Furthermore, let θ1 be the angle between the tangent line LS2 tangent to the intersection point CP and the line LS3 perpendicular to the axial direction of the plunger 2, then θ1 > 0°.

[0095] In other words, the fixing structure of the two members applied to the high-pressure fuel supply pump 100 in this embodiment is A fixing structure for two members, which fixes a first member (pump body) 1 having a cylindrical inner circumferential surface 1c1 and a second member (cylinder) 6 having a cylindrical outer circumferential surface 6a, The second member (cylinder) 6 has a curved surface portion 6d at one end 6a1 in the direction along the center line 1A (axial direction) of the outer peripheral surface 6a, which is formed by a curved surface that starts from this end 6a1 as a starting point 6d1 and decreases in diameter so as it moves away from the outer peripheral surface 6a along the center line 1A, becoming convex radially outward. The first member (pump body) 1 has a pressed surface 1g formed by pressing the peripheral edge 1c2 of the inner circumferential surface 1c1 of the first member (pump body) 1 while the second member (cylinder) 6 is fixed to the inner circumferential surface 1c1 of the first member (pump body) 1, and a plastically deformed portion 1x1 that is plastically deformed radially inward from the outer circumferential surface 6a of the second member (cylinder) 6. When a circle C1 is drawn with the radial outer endpoint 1g1 of the pressed surface 1g as the radius, using the length R1 of the line segment LS1 connecting the starting point 6d1 of the curved surface 6d and the radial outer endpoint 1g1 of the pressed surface 1g of the first member (pump body) 1, the circle C1 intersects with the curved surface 6d. At the intersection point CP of circle C1 and the curved surface 6d, the tangent line LS2 that is tangent to the curved surface 6d has an angle θ1 greater than 0° between it and the line LS3 that is perpendicular to the center line 1A.

[0096] In this case, the contact initiation point 6d3 is located radially outward (on the outer circumference side) than the radially inward endpoint 6d2 of the curved surface portion 6d. That is, in the two-member fixing structure of this embodiment, the contact initiation point 6d3 where the plastically deformed portion 1x1 of the first member (pump body) 1 and the second member (cylinder) 6 begin to come into contact is located radially outward than the radially inward endpoint 6d2 of the curved surface portion 6d.

[0097] When the contact initiation point 6d3 is positioned directly below the radially inner endpoint 6d2, i.e., at the position of the radially inner endpoint 6d2, θ1 becomes 0°, and a large bending moment is generated in the plastically deformed portion 1x1 of the protrusion 1x, making stress concentration likely.

[0098] In this embodiment, the contact initiation point 6d3 is located radially outward (towards the outer circumference) than the radially inward endpoint 6d2 of the curved surface portion 6d, thereby reducing the bending moment generated in the plastically deformed portion 1x1 of the protrusion 1x. That is, by setting θ > 0°, it becomes difficult for a large bending moment to be generated in the plastically deformed portion 1x1 of the protrusion 1x, thus avoiding stress concentration at a single point. As a result, in this embodiment, even when the system fuel pressure becomes high, for example, 50 MPa, the shape of the protrusion 1x can be made such that it does not undergo fatigue failure.

[0099] Let's return to Figure 7 for explanation. In order to achieve θ1 > 0°, it is preferable to set θ2 to a range of θ2 > 45°, where θ2 is the angle between the line segment LS1 and the pressed surface 1g. That is, the angle θ2 between the line segment LS1, which connects the starting point 6d1 and the radially outer endpoint 1g1 of the pressed surface 1g, and the pressed surface 1g is greater than 45°. In the crimping process, a load is applied to the pressed surface 1g to deform the protrusion 1x, but by setting θ2 > 45°, the deformation of the protrusion 1x is suppressed, and θ1 > 0° can be achieved.

[0100] The arrangement of the R portion will be explained using Figure 10. Figure 10 is an explanatory diagram relating to one embodiment of the present invention, showing the relationship between the intersection points of circles C1-1, C1-2, and C1-3, centered at the radially outer endpoint 1g1 of the pressed surface 1g, and the curved surface portion. (a-1), (a-2), (b), (c-1), and (c-2) each show different relative positional relationships between the curved portion (R portion) 6d and the radially outer endpoint 1g1 of the pressed surface 1g. In the figure, 6d is song In the diagram, 6d1 represents the radial outer endpoint (starting point) of the curved surface 6d, 6d2 represents the radial inner endpoint of the curved surface 6d, Or represents the center of the curved surface 6d, and CP represents the intersection point of circle C1 and the curved surface 6d. To avoid making the diagrams complicated, the signs are only shown in some of the diagrams, but they are common to (a-1), (a-2), (b), (c-1), and (c-2).

[0101] The multiple dashed lines are line segments connecting the center Or of the curved surface 6d and the radially outer endpoint 1g1 of the pressed surface 1g. θ3 is the angle between the dashed line and the pressed surface 1g. (b) shows the case where the center Or of the curved surface 6d lies on the dashed line where θ3 = 45°. (a-1) and (a-2) show the case where the center Or of the curved surface 6d lies on the dashed line where θ3 < 45°. (c-1) and (c-2) show the case where the center Or of the curved surface 6d lies on the dashed line where θ3 > 45°.

[0102] In (b), the circle C1 described above passes through the radially inner endpoint 6d2, and the relationship θ1 > 0° described above is not satisfied. In (a-1) and (a-2), the aforementioned circle C1(C1-1,C1-2) intersects with the curved surface 6d, and the relationship θ1>0° described above is satisfied. In (c-1) and (c-2), the circle C1(C1-1,C1-2) described above passes radially inside the radially inside endpoint 6d2, and the relationship θ1>0° described above is not satisfied.

[0103] Thus, in order to satisfy the above-mentioned relationship θ1 > 0°, the angle θ3 between the line segment LS6 (see Figure 8) connecting the center Or of the curved surface 6d and the radially outer endpoint 1g1 of the pressed surface 1g, and the pressed surface 1g, must be 45°. less than It is necessary to set (θ3 < 45°). In this case, it is also preferable to set θ2 to the range θ2 > 45°. Shii .

[0104] In other words, the fixing structure of the two members in this embodiment is A fixing structure for two members, which fixes a first member 1 having a cylindrical inner circumferential surface 1c1 and a second member 6 having a cylindrical outer circumferential surface 6a, The second member 6 has a curved surface portion 6d at one end 6a1 in the direction along the center line 1A of the outer peripheral surface 6a, which is formed by a curved surface that starts from this end 6a1 as a starting point 6d1 and decreases in diameter so as it moves away from the outer peripheral surface 6a along the center line 1A, becoming convex radially outward. The first member 1 includes a pressed surface 1g formed by pressing the peripheral edge of the inner circumferential surface 1c1 of the first member 1 while the second member 6 is fixed to the inner circumferential surface 1c1 of the first member 1, and a plastically deformed portion 1x1 that is plastically deformed radially inward from the outer circumferential surface 6a of the second member 6. The angle θ3 between the line segment LS6, which connects the center of the radius Or of the curved portion 6d and the radially outer endpoint 1g1 of the pressed surface 1g of the first member 1, and the line perpendicular to the center line 1A (in this embodiment, the pressed surface 1g), is: 45° It will be set to be smaller than that.

[0105] Figure 11 is a conceptual diagram showing a fixing structure for two members according to one embodiment of the present invention. The pump body 1 is made of a softer material than the cylinder 6 and the punch TL that presses the pressed part 1g. When the protrusion 1x of the pump body 1, shown by the dashed line, is pressed with the punch TL, the material in part b undergoes plastic flow as shown by the arrow in the figure. At this time, the material in part b flows radially in the direction where it has room to escape, and thus flows almost entirely to part a.

[0106] The material flowing from section b to section a loses its way at the press-fit section between the pump body 1 and the cylinder 6, and the flow is blocked. If pressing by the punch TL continues after the flow is blocked, the flowing material will exceed the curved section 6d and reach the radial surface 6f (see Figure 9). As a result, the above conditions, such as θ1 > 0°, are no longer met. In order to satisfy the above conditions, it is necessary to accurately determine and control the amount of material undergoing plastic flow. The amount of material to be plastically flowed can be determined experimentally. However, if the relative positional relationship between the pump body 1 and the cylinder 6 changes during manufacturing, it becomes impossible to accurately control the amount of material undergoing plastic flow.

[0107] In this embodiment, the pump body 1 and cylinder 6 are fixed by press-fitting before the protrusion 1x is pressed by the punch TL. That is, the outer circumferential surface 6a of the second member (cylinder) 6 is press-fitted into the inner circumferential surface 1c1 of the first member (pump body) 1 to fix the second member 6 and the first member 1. This suppresses changes in the relative positional relationship between the pump body 1 and the cylinder 6, and allows for precise control of the amount of material undergoing plastic flow. By satisfying the above conditions, a two-member fixing structure and a high-pressure fuel supply pump can be provided in which the protrusion 1x is less susceptible to fatigue failure.

[0108] The embodiments of the two-member fixing structure and high-pressure fuel supply pump according to the present invention, including their effects, have been described above. However, the two-member fixing structure and fuel pump according to the present invention are not limited to the embodiments described above, and various modifications are possible without departing from the gist of the invention as described in the claims. Furthermore, the embodiments described above have been explained in detail in order to explain the present invention in an easy-to-understand manner, and the two-member fixing structure and high-pressure fuel supply pump according to the present invention are not necessarily limited to those having all the configurations described. [Explanation of Symbols]

[0109] 100...High-pressure fuel supply pump, 1A...Centerline, 1...First member (pump body), 1c1...Inner circumferential surface of the first member (pump body) 1, 1c2...Peripheral edge of the inner circumferential surface 1c1 of the first member (pump body) 1, 1g...Pressed surface, 1g1...Radial outer end point of the pressed surface 1g, 1x1...Plastically deformed portion, 6...Second member (cylinder), 6a...Outer circumferential surface of the second member (cylinder) 6, 6a1...One end of the outer circumferential surface 6a of the second member (cylinder) 6, 6d...Curved surface portion, 6d1...Starting point of the curved surface portion 6d, 6d2...Radial inner end point of the curved surface portion 6d, 6d3...Contact between the plastically deformed portion 1x1 and the second member (cylinder) 6 C1...a circle centered at the radially outer endpoint 1g1, CP...the intersection of circle C1 and the curved surface 6d, LS1...a line segment connecting the starting point 6d1 of the curved surface 6d and the radially outer endpoint 1g1 of the pressed surface 1g, LS2...a tangent line tangent to the curved surface 6d at intersection CP, LS6...a line segment connecting the center Or of the curved surface 6d and the radially outer endpoint 1g1 of the pressed surface 1g of the first member 1, Or...the center of the radius of the curved surface 6d, θ1...the angle between the line perpendicular to the center line 1A and the tangent line LS2, θ2...the angle between line segment LS1 and the pressed surface 1g, θ3...the angle between line segment LS6 and the line perpendicular to the center line 1A.

Claims

1. A fixing structure for two members, which fixes a first member having a cylindrical inner surface and a second member having a cylindrical outer surface, The second member is provided with a curved surface portion at one end in the direction along the center line of the outer circumferential surface, which is a curved surface that starts from this end and becomes convex radially outward as it moves away from the outer circumferential surface along the center line, The first member comprises a pressed surface formed by pressing the peripheral edge of the inner circumferential surface of the first member while the second member is fixed to the inner circumferential surface of the first member, and a plastically deformed portion that is plastically deformed radially inward from the outer circumferential surface of the second member. When a circle is drawn with the radial outer end point of the pressed surface as the radius, using the length of the line segment connecting the starting point of the curved surface and the radial outer end point of the pressed surface of the first member as the radius, the circle intersects the curved surface. The contact initiation point where the plastically deformed portion of the first member and the second member begin to come into contact is located radially outward from the radially inner end point of the curved surface portion. A fixing structure of two members in which the tangent line that touches the curved surface at the intersection of the circle and the curved surface has an angle greater than 0° between it and a line perpendicular to the center line.

2. In the fixing structure of two members according to claim 1, A fixing structure for two members in which the angle between the line segment connecting the starting point and the radially outer end point of the pressed surface and the pressed surface is greater than 45°.

3. In the fixing structure of two members according to claim 1, A fixing structure for two members, wherein the outer surface of the second member is press-fitted into the inner surface of the first member to fix the second member and the first member together.

4. In the fixing structure of two members according to Claim 1, A fixing structure for two members, wherein the angle between the line segment connecting the center of the radius of the curved portion and the radially outer endpoint of the pressed surface of the first member and a line perpendicular to the center line is set to be less than 45°.

5. A high-pressure fuel supply pump comprising a pump body and a cylinder, A high-pressure fuel supply pump in which the pump body is the first member and the cylinder is the second member, and the pump body and the cylinder are fixed by the two-member fixing structure described in claim 1.

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