Vehicle component and method of manufacturing a valve seat

Abstract

This invention provides a vehicle component capable of suppressing cladding defects in laser cladding processing and a method for manufacturing a valve seat using the vehicle component. The vehicle component according to this invention is a vehicle component that has undergone laser cladding processing by spraying metal powder onto a metal vehicle component and irradiating it with a laser, thereby melting the metal powder and cladding it onto the vehicle component. It comprises: a metal main body; and a weld overlay portion, which is formed by cladding the solidified molten metal powder onto the processing surface of the main body. The distance from the edge of the weld overlay portion to the edge of the processing surface on which the weld overlay portion is formed is 0 mm or more and 4 mm or less.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a vehicle component and a valve seat. Background Technology

[0002] Patent Document 1 discloses a laser cladding method that, when performing laser cladding on multiple valve seat portions in the cylinder head of an automotive engine, prevents poor cladding caused by cladding metal adhering to unprocessed valve seat portions. This laser cladding method includes the following steps: after processing the initial valve seat portions, a cleaning mechanism is used to remove the cladding metal adhering to the unprocessed valve seat portions.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2002-089358 Summary of the Invention

[0004] The inventors of this invention have discovered a problem where poor cladding occurs when unmelted cladding metal adheres to an area of ​​the valve seat where laser cladding processing is planned in the future. In the laser cladding method disclosed in Patent Document 1, it is impossible to prevent unmelted cladding metal from adhering to the area where laser cladding processing is planned. Therefore, poor cladding may occur due to cladding metal adhering during processing.

[0005] The present invention was made in view of the above-mentioned actual situation, and provides a vehicle part capable of suppressing poor cladding in laser cladding process and a method for manufacturing a valve seat using the vehicle part.

[0006] One aspect of the present invention relates to a vehicle component that has undergone laser cladding processing, in which metal powder is sprayed onto a metal vehicle component and irradiated with a laser, thereby melting the metal powder and cladding it onto the vehicle component.

[0007] It comprises: a metal main body; and

[0008] The weld overlay is formed by fusing the solidified molten metal powder onto the machined surface of the main body.

[0009] The distance from the edge of the weld overlay to the edge of the machined surface on which the weld overlay is formed is 0 mm or more and 4 mm or less.

[0010] One aspect of the present invention relates to a method for manufacturing a valve seat, which involves forming a weld overlay on the inner side of a groove in a cylinder head body by laser cladding to manufacture the valve seat. The method comprises:

[0011] The blowing step involves blowing metal powder onto the inner side of a groove where the distance from the edge of the weld overlay to the edge of the machined surface where the weld overlay is formed is 0 mm or more and 4 mm or less; and

[0012] The melting step involves melting the sprayed metal powder by irradiating it with a laser.

[0013] The laser cladding process is performed on the entire tank by starting from a portion of the tank and simultaneously performing the blowing and melting steps while continuously moving in a predetermined direction.

[0014] In the step of spraying the metal powder, by discharging a portion of the metal powder into a through hole formed inside the groove, the metal powder is prevented from adhering to an area further along the direction of movement than the area where the laser cladding process is performed.

[0015] Invention Effects

[0016] According to the present invention, a vehicle component capable of suppressing cladding defects in laser cladding processing and a method for manufacturing a valve seat using the vehicle component are provided. Attached Figure Description

[0017] Figure 1 (a) is a schematic perspective sectional view of a vehicle component before the formation of the weld overlay according to an embodiment of the present invention. Figure 1 (b) is a schematic perspective sectional view of the vehicle component according to an embodiment of the present invention after the weld overlay is formed. Figure 1 (c) is a schematic perspective sectional view of a vehicle component before the formation of the weld overlay according to an embodiment of the present invention. Figure 1 (d) is a cross-sectional view of a vehicle component according to an embodiment of the present invention.

[0018] Figure 2 This is a flowchart of a valve seat manufacturing method according to an embodiment of the present invention.

[0019] Figure 3 (a) is a schematic perspective cross-sectional view of a vehicle component undergoing laser cladding processing according to an embodiment of the present invention. Figure 3 (b) is an enlarged view of the laser cladding processing location in a vehicle component according to an embodiment of the present invention. Figure 3 (c) is a cross-sectional view of a vehicle component with unclad portions. Figure 3 (d) is an enlarged view of the laser cladding processing location in the vehicle component according to the embodiments of the present invention.

[0020] Figure 4 This is a graph showing the relationship between the horizontal distance d from the edge of the weld overlay to the front end of the protrusion in a vehicle component according to an embodiment of the present invention and the deposition rate.

[0021] Figure 5 (a) is a cross-sectional view of a vehicle component according to an embodiment of the present invention. Figure 5 (b) is a binarized image of a cross-sectional view of a vehicle component according to an embodiment of the present invention.

[0022] Figure 6 (a) is a cross-sectional view of a vehicle component according to an embodiment of the present invention, when the shape of the protrusion is changed. Figure 6 (b) is a cross-sectional view of a vehicle component according to an embodiment of the present invention, when the shape of the protrusion is changed. Detailed Implementation

[0023] Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to these embodiments. Furthermore, for clarity, the following description and drawings have been appropriately simplified.

[0024] <Structure of vehicle components>

[0025] Figure 1 (a) is a schematic perspective sectional view of a vehicle component before the formation of the weld overlay according to an embodiment of the present invention. Figure 1 (b) is a schematic three-dimensional sectional view after the weld overlay is formed. Additionally, Figure 1 The right-handed xyz orthogonal coordinate system shown in (a) and (b) is for convenience in representing the positional relationships of constituent elements. The positive z-axis is vertically upward, and the xy plane is horizontal, including those described later. Figure 1 (c)(d) Figure 3 and Figure 6 of Figures 1-6 The attached diagrams are common to each other.

[0026] Vehicle component 1 includes a main body 11, a groove 12, a protrusion 13, and a weld overlay 14.

[0027] Vehicle component 1 is, for example, a cylinder head serving as an engine component of a vehicle, having two, four, or other numbers of slots 12 provided relative to a main body 11. In the case of a cylinder head, the slots 12, protrusions 13, and the weld overlay 14 formed from solidified metal powder within the slots 12 constitute the valve seat portion of the cylinder head. Furthermore, this valve seat portion is formed by laser cladding: irradiating metal powder with a laser, thereby melting the metal powder and cladding it onto the vehicle component 1. The vehicle component 1 need only be a component requiring the process of forming the weld overlay 14 through laser cladding.

[0028] The main body 11 is the main body of the vehicle component 1 whose shape and size are determined according to the purpose of the vehicle component 1. The material of the main body 11 is, for example, ferrous metals such as iron or carbon steel, or alloy steel such as stainless steel.

[0029] The groove 12 is formed on the surface of the main body 11. Although in Figure 1(a) is omitted, but the groove 12 may have a bottom surface on the negative z-axis side, in which case the groove 12 becomes a recess. Furthermore, the groove 12 may not have a bottom surface on the negative z-axis side, in which case the groove 12 becomes a through hole formed from the first surface of the main body 11 to the second surface of the main body 11. For example, in the case where the vehicle component 1 is a cylinder head, since the fuel-air mixture passes through the groove 12, the groove 12 is preferably a through hole.

[0030] A protrusion 13 is formed on the inner surface of the groove 12. More specifically, the protrusion 13 is formed by protruding in the direction that narrows the inner diameter of the groove 12 along the circumferential direction of the inner surface of the groove 12. Here, the side surface of the protrusion 13 is... Figure 1 In (a), the positive z-axis side and the negative z-axis side of the protrusion 13 are machined surfaces. The material of the protrusion 13 is, for example, ferrous metals such as iron or carbon steel, or alloy steel such as stainless steel.

[0031] In addition, Figure 1 In (a), the protrusion 13 protrudes in the z-axis direction with a predetermined thickness, and thus, when viewed from the protrusion 13, the corner portion, which serves as the boundary between the inner surface of the groove 12 and the side surface of the protrusion 13, is formed on both the positive z-axis and negative z-axis sides. For example, as shown in... Figure 1 As shown in (c), the corner portion may not be formed on the negative z-axis side when viewed from the protrusion 13, but rather the protrusion 13 may be formed by narrowing the inner diameter of the groove 12 at a predetermined location. That is, the groove 12 and the protrusion 13, which are integrally formed, may also form a recess or through hole with a shape that narrows at a predetermined position. This shape is formed, for example, by forming a recess or through hole with a predetermined inner diameter as the groove 12 on the main body 11, and enlarging the diameter of the entrance portion of the formed groove 12 to be larger than the inner diameter of the groove 12. In addition, as Figure 1 As shown in (a), the corner can be an R-shape or a roughly vertically bent shape.

[0032] like Figure 1 As shown in (b), the weld overlay 14 is formed as a solidified form of molten metal powder at the boundary portions of the inner side of the groove 12 and the side of the protrusion 13. That is, the weld overlay 14 is formed on the machined surface. Here, for example, in the case where the vehicle component 1 is a cylinder head, the weld overlay 14 functions as a valve seat portion of the cylinder head by forming the boundary portion on the z-axis positive direction side of the boundary portions of the inner side of the groove 12 and the side of the protrusion 13. The material of the weld overlay 14 can be any material that is melted by a laser irradiated during laser cladding processing, such as an alloy containing metals such as aluminum, iron, nickel, cobalt, chromium, molybdenum, and tungsten. Furthermore, it can also be a material composed of metals such as cobalt or molybdenum with inorganic substances such as carbides or oxides.

[0033] Figure 1 (d) is a cross-sectional view of the vehicle component according to an embodiment of the present invention, cut along a plane parallel to the yz plane. Figure 1 As shown in (d), the weld overlay 14 is formed at the boundary of the inner side of the groove 12 and the side of the protrusion 13. Here, the horizontal distance from the inner side of the groove 12 to the front end of the protrusion 13 (i.e., the edge of the machined surface) is defined as D (mm), and the horizontal distance from the edge of the weld overlay 14 to the front end of the protrusion 13 (i.e., the edge of the machined surface) is defined as d (mm).

[0034] <Methods for Manufacturing Vehicle Components>

[0035] Next, refer to Figure 2 The manufacturing method of the valve seat according to the embodiments of the present invention will be described. Figure 2 This is a flowchart of a valve seat manufacturing method according to an embodiment of the present invention.

[0036] First, metal powder is sprayed onto the inner side of the groove 12 and the boundary portion of the side of the protrusion 13 of the vehicle component 1 (step S1). Step S1 is performed, for example, by ejecting metal powder and protective gas from a nozzle. In step S1, by ejecting metal powder and protective gas, the metal powder and the flow of protective gas are supplied to the laser cladding processing position. As a protective gas, air can be used, but inactive gases such as nitrogen and argon can also be used.

[0037] Next, the sprayed metal powder is irradiated with a laser to melt it (step S2). In step S2, the molten metal powder solidifies to form a weld overlay 14. Here, for example, if the vehicle component 1 is a cylinder head, by performing steps S1 and S2, a weld overlay 14 is formed on the inner side of the groove 12 by laser cladding, thereby manufacturing a valve seat portion. The type of laser used for irradiation is, for example, a CO2 laser or a semiconductor laser. Furthermore, the metal powder can also be dissolved by irradiating with an electron beam instead of a laser.

[0038] Alternatively, steps S1 and S2 can be performed simultaneously. In the laser cladding process used in embodiments of the present invention, for example... Figure 3 As shown in (a), a weld overlay 14 is formed by simultaneously spraying metal powder M and irradiating the boundary portions of the inner side surface of the groove 12 and the side surface of the protrusion 13 with laser L. At this time, the laser cladding process begins at a portion of the boundary portions of the inner side surface of the groove 12 and the side surface of the protrusion 13, and is performed by continuously moving the metal powder M spraying position and the laser L irradiation position in a predetermined moving direction. Here, the boundary portion is laser cladding processed entirely by performing laser cladding processing from a portion of the boundary portions of the inner side surface of the groove 12 and the side surface of the protrusion 13 across the entire circumference.

[0039] Furthermore, the movement of the laser cladding processing position A in laser cladding processing is relative. Therefore, the laser cladding processing position A can be moved by moving, tilting, or rotating the laser L, or by moving, tilting, or rotating the vehicle component 1. Moreover, the laser cladding processing position A can also be moved by moving, tilting, or rotating both the laser L and the vehicle component 1. To move, tilt, or rotate the laser L, the laser irradiation device (not shown) irradiating the laser L can be moved, tilted, or rotated itself, or a reflector or prism can be used to control the direction of travel of the laser L.

[0040] Figure 3 (b) is Figure 3 (a) is an enlarged view of the laser cladding location. During laser cladding, a portion of the metal powder M ejected from the nozzle disperses and adheres to the surface of vehicle part 1. Here, for example, in Figure 3 In (b), when the laser cladding processing position A moves to the right, metal powder M adheres to an area further to the right of the moving direction than the laser cladding processing position A. If laser cladding continues in this state, the amount of adhered metal powder M is excessive compared to the expected amount at laser cladding processing position A. Therefore, the irradiation intensity of laser L is insufficient, such as... Figure 3 As shown in (c), an unclad area B is generated on the side of the protrusion 13, which may cause poor cladding.

[0041] To solve this problem, in vehicle component 1, such as Figure 3 As shown in (d), the horizontal distance d from the edge of the weld overlay 14 to the front end of the protrusion 13 is shortened. In other words, in vehicle component 1, the groove 12 is enlarged in the direction of the hollow arrow by reducing the protrusion height of the protrusion 13. By enlarging the groove 12, the flow rate of the protective gas discharged from the nozzle flowing towards the inner side of the groove 12, i.e., the negative z-axis side, is increased. Due to the increased gas flow, a portion of the metal powder M adhering to the right side of the laser cladding processing position A is discharged to the inner side of the groove 12. Therefore, the metal powder M is prevented from adhering to the right side of the laser cladding processing position A.

[0042] Furthermore, increasing the flow rate of the protective gas ejected from the nozzle itself can increase the flow rate of the gas flowing into the interior of the groove 12. However, in this case, the amount of metal powder M scattered along with the increase in gas flow rate also increases. Therefore, the amount of metal powder M supplied to the laser cladding processing position A is unstable, and the welding quality decreases. The vehicle component 1 according to the embodiment of the present invention can increase the flow rate of the gas flowing into the interior of the groove 12 without changing the total amount of gas flow, thus achieving the effect of suppressing cladding defects in laser cladding processing.

[0043] Figure 4 This is a graph showing the relationship between the horizontal distance *d* from the edge of the weld overlay to the front end of the protrusion and the deposition rate. The graph is plotted by overlaying the values ​​of *d* corresponding to the values ​​of *D* on a graph where the horizontal distance *D* is taken on the horizontal axis from the inner side of the groove 12 to the front end of the protrusion 13, and the deposition rate is taken on the vertical axis. The deposition rate is measured by cutting the vehicle part 1 along the positive z-axis from the side of the protrusion 13 on a horizontal plane P at a height of 1.5 mm and observing the results. Figure 5 (a) The calculation is performed using a cross-sectional view of the weld overlay 14 shown. Here, the cross-sectional view of the weld overlay 14 is obtained by using a cross-sectional view of the weld overlay 14 shown in (a). Figure 5 (b) The defect G, which appears as black in the weld overlay 14, is observed in the binarized image of the cross-sectional view of the weld overlay 14. The deposition rate (%) is calculated by applying the following formula (1) to the binarized cross-sectional image of the weld overlay 14.

[0044] [Formula 1]

[0045]

[0046] like Figure 4 As shown by the hollow arrow, the horizontal distance d from the edge of the weld overlay 14 to the front end of the protrusion 13 is preferably 0 mm or more and 4 mm or less. By performing laser cladding to make the value of d 0 mm or more and 4 mm or less, the flow rate of gas flowing into the inner side of the groove 12 during laser cladding increases. Therefore, as... Figure 3 As shown in (d), it is possible to achieve the effect that the metal powder M adhering in the region further along the moving direction than the region where laser cladding is performed is discharged beyond the edge of the processed surface. With this effect, a high cladding rate of over 94% can be achieved.

[0047] In addition, such as Figure 6 As shown in (a), a portion of the side surface of the protrusion 13 may also have a shape that is inclined towards the negative z-axis direction. Furthermore, as... Figure 6As shown in (b), the inclined surface can also have a curved shape. By tilting a portion of the side surface of the protrusion 13 toward the negative z-axis direction, it is also possible to increase the flow rate of the protective gas flowing toward the negative z-axis direction in step S1. At this time, the horizontal distance d1 from the edge of the weld overlay portion 14 to the end of the surface of the side surface of the protrusion 13 that is approximately parallel to the xy plane is preferably 0 mm or more and 4 mm or less. By performing laser cladding to make the value of d1 0 mm or more and 4 mm or less, it is possible to obtain the effect that the metal powder M adhering in the region further toward the moving direction side than the region where the laser cladding is performed is discharged to the inside of the groove portion 12.

[0048] As explained above, the vehicle component according to the embodiments of the present invention reduces the protrusion height of the protrusion formed in the groove and expands the diameter of the groove. Therefore, it is possible to achieve the effect that metal powder adhering to a region further in the direction of movement than the processing position during laser cladding is discharged beyond the edge of the processing surface and into the inside of the groove. Thus, it is possible to provide a vehicle component capable of suppressing cladding defects during laser cladding and a method for manufacturing a valve seat using the vehicle component.

[0049] Symbol Explanation

[0050] 1-Vehicle component, 11-Main body, 12-Groove, 13-Protrusion, 14-Weld overlay, A-Laser cladding processing position, B-Unclad area, G-Defect, L-Laser, M-Metal powder, P-Horizontal plane.

Claims

1. A vehicle component, comprising a vehicle component subjected to laser cladding processing by spraying metal powder onto a metal vehicle component and irradiating it with a laser, thereby melting the metal powder and cladding it onto the vehicle component, characterized in that, have: The main body is made of metal; and The weld overlay is formed by fusing the solidified molten metal powder onto the machined surface of the main body. The distance from the edge of the weld overlay to the edge of the machined surface on which the weld overlay is formed is 0 mm or more and 4 mm or less.

2. The vehicle component according to claim 1, characterized in that, The vehicle component is a cylinder head with a valve seat portion, the valve seat portion comprising: a through hole formed from a first surface of the main body portion to a second surface of the main body portion; and a protrusion that protrudes circumferentially throughout the inner surface of the through hole in a direction that reduces the inner diameter of the through hole, wherein... The weld overlay is formed at the boundary portion of the inner side surface and the side surface of the protrusion. The edge of the machined surface is the front end of the protrusion.

3. The vehicle component according to claim 1 or 2, characterized in that, The laser cladding process begins on a portion of the processing surface and is performed while continuously moving in a predetermined direction.

4. The vehicle component according to claim 3, characterized in that, In the laser cladding process, when the metal powder is sprayed onto the processing surface, a portion of the metal powder is discharged beyond the edge of the processing surface on the moving direction side.

5. A method for manufacturing a valve seat, comprising forming a weld overlay on the inner side of a groove in a cylinder head body by laser cladding to manufacture the valve seat, the method being characterized by comprising: The blowing step involves blowing metal powder onto the inner side of a groove where the distance from the edge of the weld overlay to the edge of the machined surface where the weld overlay is formed is 0 mm or more and 4 mm or less; and The melting step involves melting the sprayed metal powder by irradiating it with a laser. The laser cladding process is performed on the entire tank by starting from a portion of the tank and simultaneously performing the blowing and melting steps while continuously moving in a predetermined direction. In the step of spraying the metal powder, by discharging a portion of the metal powder into a through hole formed inside the groove, the metal powder is prevented from adhering to an area further along the direction of movement than the area where the laser cladding process is performed.

Images