WO2019151322A1

WO2019151322A1 - Valve seat and valve seat material

Info

Publication number: WO2019151322A1
Application number: PCT/JP2019/003158
Authority: WO
Inventors: 清諏訪; 祐二永岡
Original assignee: 日本ピストンリング株式会社
Priority date: 2018-01-31
Filing date: 2019-01-30
Publication date: 2019-08-08
Also published as: JP7022769B2; JPWO2019151322A1

Abstract

This valve seat is press-fit into a cylinder head for an internal combustion engine and comes into contact with a valve. The outer peripheral surface of the valve seat is provided with a rough surface region having a portion with recesses and protrusions. At least part of the rough surface region extends, starting from the end of the valve seat which is on the front side in the direction in which the valve seat is press-fit into the cylinder head (the end being hereinafter referred to as valve seat front-side end), in the press-fitting direction within a range having a length 4/5 the overall length of the valve seat in the press-fitting direction. As a result, even if a location where a structure which does not easily become dislodged from the cylinder head for the internal combustion engine is provided extends to the rear end side in the direction of press-fitting of the valve seat, the valve seat can be efficiently press-fit into the cylinder head.

Description

Valve seat and valve seat material

The present invention relates to a valve seat that is press-fitted into a cylinder head for an internal combustion engine, and a valve seat material that is a material before processing of the valve seat.

When a valve seat press-fitted into a cylinder head for an internal combustion engine (hereinafter simply referred to as a cylinder head) becomes hot due to engine operation or the like, the holding force of the valve seat by the cylinder head is insufficient, and the valve seat falls out of the cylinder head. There was a case. In order to solve the above problems, a valve seat drop-off preventing structure has been proposed (see, for example, Japanese Utility Model Laid-Open No. 01-83109). The valve seat drop-off preventing structure is expanded radially in an annular space formed by an annular groove formed on the inner peripheral surface of the cylinder head press-fitting hole and an annular groove formed on the outer peripheral surface of the valve seat. The expansion ring is inserted. When the valve seat is press-fitted into the cylinder head and mounted, the compressed expansion ring expands in the radial direction and is disposed across both annular grooves. Thereby, the movement of the valve seat in the axial direction is suppressed by the expansion ring, and the valve seat can be prevented from falling off from the cylinder head.

When the valve seat is press-fitted into the cylinder head, the valve seat drop-off prevention structure is configured so that the valve seat is pushed in the press-fitting direction while the valve seat moves in the press-fitting direction, and is inserted into the annular groove of the valve seat. An operation of pushing the expansion ring into the annular groove of the valve seat is required until the valve seat reaches a position where the pushed expansion ring contacts the wall surface of the cylinder head. After the valve seat reaches the above position, the expansion ring is pushed into the annular groove of the valve seat by the wall surface of the cylinder head, so that the pushing operation with respect to the expansion ring is not necessary. It is not preferable to press-fit the valve seat into the cylinder head while performing the two operations because it complicates the press-fitting operation. For this reason, the position where the annular groove is formed is preferably in the vicinity of the leading side in the press-fitting direction of the valve seat so that the expansion ring contacts the wall surface of the cylinder head immediately after the valve seat is press-fitted.

On the other hand, when the annular groove is provided in the cylinder head and the valve seat, it is necessary to perform groove processing with high processing accuracy. However, when the groove processing is performed on a thin valve seat having a small axial thickness, the component dimensions are small. Therefore, it is difficult to ensure the desired processing accuracy.

However, it is preferable that the cylinder head can be efficiently pressed into the cylinder head even if a structure for preventing the valve seat from dropping is provided not only in the vicinity of the head side in the press-fitting direction of the valve seat but also on the rear side in the press-fitting direction of the valve seat.

In view of such circumstances, the present invention provides a valve seat that can efficiently press into the cylinder head even when the position where the structure that does not easily fall off from the cylinder head extends to the rear side in the press-fitting direction of the valve seat, and An object of the present invention is to provide a valve seat material which is a material before processing the valve seat.

The present invention has been made to solve the above problems, and the valve seat of the present invention is a valve seat that is press-fitted into a cylinder head for an internal combustion engine and abuts against the valve, and the outer periphery of the valve seat A rough surface region having a concavo-convex portion on the surface, and at least a part of the rough surface region is an end of the valve seat on the near side in the press-fitting direction in which the valve seat is press-fitted into the cylinder head (hereinafter referred to as a valve seat It is provided in the range of 4/5 of the total length of the valve seat in the press-fitting direction along the press-fitting direction.

In the valve seat according to the present invention, at least a part of the rough surface region may be 2/3 of the total length of the valve seat in the press-fitting direction along the press-fitting direction starting from the front end of the valve seat. It is provided within the range of length.

Further, in the valve seat of the present invention, at least a part of the rough surface region is ½ of the total length of the valve seat in the press-fitting direction along the press-fitting direction starting from the front end of the valve seat. It is provided within the range of length.

In the valve seat of the present invention, the inner peripheral surface of the valve seat has an inclined surface region having at least one inclined surface inclined with respect to the press-fitting direction, and the rough surface region is formed of the valve seat. It has an overlapping region that overlaps the inclined surface region in the radial direction.

Further, in the valve seat of the present invention, the inclined surface region has a valve contact surface that contacts the valve, from the front end portion of the valve seat to the end portion on the far side in the press-fitting direction of the valve contact surface. The length in the press-fitting direction is approximately 1.4 mm or less.

Further, in the valve seat of the present invention, the inclined surface region has a valve contact surface that contacts the valve, from the front end portion of the valve seat to the end portion on the far side in the press-fitting direction of the valve contact surface. The length in the press-fitting direction is not more than ½ of the total length of the valve seat in the press-fitting direction.

Further, in the valve seat of the present invention, the total length of the valve seat in the press-fitting direction is approximately 4 mm or less.

The valve seat material of the present invention is a valve seat material that is a material before processing of a valve seat that is press-fitted into a cylinder head for an internal combustion engine and abuts on the valve, and is uneven on the outer peripheral surface of the valve seat material. And at least a part of the rough surface region is an end of the valve seat material (hereinafter referred to as a valve seat) corresponding to the near side in the press-fitting direction in which the valve seat is press-fitted into the cylinder head. It is provided within a range of 4/5 of the total length of the valve seat material in the press-fitting direction along the press-fitting direction.

Further, in the valve seat material according to the present invention, at least a part of the rough surface region is 2% of the total length of the valve seat material in the press-fitting direction along the press-fitting direction starting from the front end of the valve seat material. It is provided within the range of the length of / 3.

Further, in the valve seat material of the present invention, at least a part of the rough surface region is 1 of the total length of the valve seat material in the press-fitting direction along the press-fitting direction starting from the front end of the valve seat material. It is provided within the range of the length of / 2.

Further, in the valve seat material of the present invention, an inner peripheral surface of the valve seat material has an inclined surface region having at least one inclined surface inclined with respect to the press-fitting direction, and the rough surface region is the valve It has an overlapping region that overlaps the inclined surface region in the radial direction of the sheet material.

According to the valve seat and the valve seat material of the present invention, even if the position where the structure that does not easily fall off from the cylinder head reaches the rear side in the press-fitting direction of the valve seat, the press-fitting into the cylinder head can be performed efficiently. An excellent effect of being able to do so can be achieved.

It is sectional drawing of the periphery structure of a valve seat when the valve seat in embodiment of this invention is press-fitted in a cylinder head. (A) is a perspective view of the valve seat in an embodiment of the invention. (B) is a perspective view of a valve seat in another embodiment of the present invention. It is sectional drawing of a valve seat when the valve seat in embodiment of this invention is press-fitted in a cylinder head. (A) is the top view which expand | deployed the rough surface area | region of the valve seat in embodiment of this invention. (B) is sectional drawing of the rough surface area | region of the valve seat in embodiment of this invention. (C), (D) is sectional drawing of the rough surface area | region of the valve seat in another embodiment of this invention. (A) is a photograph of a secondary electron image (photographing magnification: 300 times) by a scanning electron microscope of a rough surface partial region P1, which is a partial region of the rough surface region of the valve seat shown in FIG. (B) is a photograph of a secondary electron image (photographing magnification: 300 times) of the rough surface partial region P2, which is a partial region of the rough surface region of the valve seat shown in FIG. 4, by a scanning electron microscope. (C) is a photograph of a secondary electron image (imaging magnification: 300 times) obtained by a scanning electron microscope of a rough surface partial region P3 which is a partial region of the rough surface region of the valve seat shown in FIG. It is a flowchart which shows the flow of manufacture of the valve seat in embodiment of this invention. (A) is the cross-sectional photograph which cut | disconnected the uneven | corrugated | grooved part of the valve seat in embodiment of this invention formed from the copper impregnation sintered compact in the valve seat radial direction along the valve seat axial direction. (B) is an enlarged view of the cross-sectional photograph shown in (A). (A) is a photograph showing the distribution of copper in the valve seat in the embodiment of the present invention formed from a copper-impregnated sintered body. (B) is a photograph showing the distribution of iron in the valve seat in the embodiment of the present invention formed from a copper-impregnated sintered body. It is explanatory drawing for demonstrating the cross-sectional shape of the valve seat raw material in embodiment of this invention, and the cross-sectional shape of the valve seat formed by processing the said valve seat raw material. (A) is the table | surface which put together the result and conditions at the time of measuring a detachment load with the high temperature holding force measuring apparatus with respect to the some valve seat in embodiment of this invention created on different conditions. (B) is explanatory drawing for demonstrating each condition of the some valve seat in embodiment of this invention produced on different conditions. It is sectional drawing which shows the outline of a high temperature holding force measuring apparatus typically.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The accompanying drawings are examples of embodiments for carrying out the present invention, and in the drawings, the same reference numerals denote the same components. Moreover, the shape and dimensional ratio of each part in each figure are not necessarily accurate.

<Peripheral structure of valve seat>
With reference to FIG. 1, the peripheral structure of the valve seat 1 when the valve seat 1 in the embodiment of the present invention is press-fitted into the cylinder head 2 will be described. The cylinder head 2 has a holding region 8 that extends toward the intake passage 3 starting from an opening 6 that communicates the intake passage 3 and the combustion chamber 5. The holding area 8 is an area where the valve seat 1 is held. The valve seat 1 is press-fitted into the holding region 8 from the combustion chamber 5 side. Thereby, the valve seat 1 is held in the holding region 8. In addition, although light metal alloys, such as an aluminum alloy, are mentioned as a material which comprises the cylinder head 2, for example, It is not limited to this, What is used as a material of a cylinder head may be used.

Here, the direction in which the valve seat 1 is press-fitted into the holding region 8 of the cylinder head 2 is defined as the press-fitting direction. Specifically, the press-fitting direction is a direction from the combustion chamber 5 side toward the intake passage 3 side. In the present embodiment, the press-fitting direction is parallel to the axial direction of the valve seat 1 (hereinafter referred to as the valve seat axial direction). Therefore, in this embodiment, the press-fitting direction may be appropriately read as the valve seat axial direction. In the present embodiment, the valve seat axial direction may be appropriately read as the press-fitting direction. The press-fitting direction and the valve seat axial direction are parallel to the Y-axis shown in FIG. The intake passage 3 may be read as an exhaust passage.

The valve 7 is reciprocated along the press-fitting direction by a reciprocating mechanism (not shown). The valve 7 has a valve face 7 </ b> A that contacts the valve seat 1. When the valve 7 moves in the press-fitting direction (Y-axis positive direction), the valve face 7A of the valve 7 contacts the valve seat 1. Thereby, the intake passage 3 and the combustion chamber 5 are spatially separated. Further, when the valve 7 moves in the direction opposite to the press-fitting direction (Y-axis negative direction), the valve face 7A is separated from the valve seat 1. As a result, the intake passage 3 and the combustion chamber 5 are in a spatially communicating state.

<Overall valve seat>
A valve seat 1 according to an embodiment of the present invention will be described with reference to FIGS. The valve seat 1 is an annular body formed by processing a material into an annular shape. A cross section of the annular body cut in the valve seat axial direction has a shape as shown in FIG. As shown in FIG. 2A, the valve seat 1 has a center shaft 10, a rear side opening 11, a front side opening 12, an inner peripheral surface 13, an outer peripheral surface 14, and a rough surface region 15. .

<Valve seat material>
As a material of the valve seat 1, for example, all materials used for manufacturing a valve seat such as a sintered body or a melted material are included in the present invention. In particular, as a material for the valve seat 1, it is preferable to use a sintered body made of an iron-based sintered alloy, a melted material, or the like. This is because the iron-based sintered alloy is excellent in workability and manufacturability, and it is easy to adjust characteristics to be provided as a valve seat.

Examples of the iron-based sintered alloy that is the material of the valve seat 1 include, for example, C: 0.4 to 1.5% by mass%, or Ni, Co, Cr, Mo, V, W, Si, It is preferable that one or two or more selected from S, Mn, and B are contained in a total of 40% or more, and the balance has a base part composition composed of Fe and inevitable impurities. The sintered body made of an iron-based sintered alloy further includes solid lubricant particles such as MnS, CaF ₂ , and BN in the matrix phase having the above composition, a hard Vickers hardness HV of 500 to 1200 HV0.1. It is preferable to disperse hard particles such as Mo—Si—Fe intermetallic compound particles, Mo—Si—Ni intermetallic compound particles, and Co-based intermetallic compound particles. Note that particles for the purpose of improving machinability may be dispersed.

<Central axis and opening of valve seat>
As shown in FIG. 2, the central axis 10 is a central axis of an annular body constituting the valve seat 1. As shown in FIGS. 1 and 2, the back side opening 11 is formed in the back in the press-fitting direction (Y-axis positive direction) when the valve seat 1 is press-fitted into the holding region 8 of the cylinder head 2 and held in the holding region 8. It is an opening of the valve seat 1 located on the side. The front side opening 12 is an opening of the valve seat 1 located on the near side in the press-fitting direction (Y-axis positive direction) when the valve seat 1 is press-fitted into the holding region 8 of the cylinder head 2 and held in the holding region 8. is there.

<Inner peripheral surface of valve seat>
The inner peripheral surface 13 of the valve seat 1 is an annular surface surrounding the central axis 10 as shown in FIG. Moreover, the inner peripheral surface 13 of the valve seat 1 has an axially extending surface region 130 and an inclined surface region 131, as shown in FIG. When the inner peripheral surface 13 is cut along a plane perpendicular to the valve seat axial direction and the inner peripheral surface 13 of the valve seat 1 is divided into two regions, the region on the back opening 11 side of the inner peripheral surface is the axial direction. It corresponds to the extended surface region 130, and the region on the front opening 12 side corresponds to the inclined surface region 131.

<Axial extending surface area>
As shown in FIG. 3A, the axially extending surface region 130 is configured by a surface that extends substantially parallel to the valve seat axial direction among the regions that constitute the inner peripheral surface 13 of the valve seat 1. It is an area. Specifically, the axially extending surface region 130 is configured by the axially extending surface 132. The axially extending surface 132 constitutes a part of the inner peripheral surface 13 and is an annular surface extending from the back side opening 11 toward the front side opening 12 substantially parallel to the valve seat axial direction. is there.

<Inclined surface area>
As shown in FIG. 3A, the inclined surface region 131 is a region of the axially extending surface region 130 on the front opening 12 side in the valve seat axial direction in the region constituting the inner peripheral surface 13 of the valve seat 1. Starting from the end portion 130A (hereinafter referred to as the axially extending surface region front side end portion), the end portion 1A of the valve seat 1 on the front side opening 12 side in the valve seat axial direction (hereinafter referred to as the valve seat front side end). It is an area constituted by a surface extending inclined to the valve seat axial direction. Specifically, the inclined surface region 131 starts from the axially extending surface region near side end portion 130 </ b> A from the back side opening 11 side to the near side opening 12 side along the valve seat axial direction (direction opposite to the press-fitting direction: Y). It is comprised by the at least 1 cyclic | annular inclined surface extended to the outer side of the radial direction (henceforth a valve seat radial direction) of the valve seat 1 as it progresses to an axial negative direction. As shown in FIG. 3A, the valve seat 1 in the present embodiment has, for example, a plurality of inclined surfaces having different inclination angles with respect to the central axis 10 (the valve seat axial direction), and the inclined surfaces are continuously connected. Extend to the front end 1A of the valve seat.

The valve seat radial direction is the radial direction of the annular body constituting the valve seat 1. In FIG. 3A, the valve seat radial direction corresponds to, for example, the X-axis direction.

In the present embodiment, as shown in FIG. 3A, the inclined surface region 131 includes an intermediate inclined surface 133, a valve contact surface 134, and an opening-side inclined surface 135. The above configuration of the inclined surface region 131 is an example, and may be configured by only the valve contact surface 134, or may be configured by the valve contact surface 134 and one inclined surface or three or more inclined surfaces. May be.

The intermediate inclined surface 133 is an inclined surface that is located closer to the rear opening 11 than the valve contact surface 134. Specifically, the intermediate inclined surface 133 continues to the axially extending surface 132 and extends to the valve contact surface 134. That is, the intermediate inclined surface 133 extends to the valve contact surface 134 starting from the end portion 132A of the axially extending surface 132 on the front opening 12 side in the valve seat axial direction. As shown in FIG. 3A, the intermediate inclined surface 133 forms an inclination angle θ ₁ (0 ° <θ ₁ <90 °) with respect to the central axis 10 (the valve seat axial direction).

The valve contact surface 134 is an inclined surface that contacts the valve face 7 </ b> A of the valve 7. The valve contact surface 134 continues to the intermediate inclined surface 133 and extends to the opening inclined surface 135. That is, the valve contact surface 134 extends to the opening-side inclined surface 135 starting from the end portion 133A of the intermediate-side inclined surface 133 on the front opening 12 side in the valve seat axial direction. As shown in FIG. 3A, the valve contact surface 134 forms an inclination angle θ ₂ (0 ° <θ ₂ <90 °) with respect to the central axis 10 (the valve seat axial direction).

The opening-side inclined surface 135 is an inclined surface located closer to the front opening 12 than the valve contact surface 134. Specifically, the opening-side inclined surface 135 continues to the valve contact surface 134 and extends to the near-side opening 12. That is, the opening-side inclined surface 135 extends to the front-side opening 12 from the end portion 134A of the valve contact surface 134 on the front-side opening 12 side in the valve seat axial direction. As shown in FIG. 3A, the opening-side inclined surface 135 forms an inclination angle θ ₃ (0 ° <θ ₃ <90 °) with respect to the central axis 10 (the valve seat axial direction).

The intermediate side inclined surface 133, the valve contact surface 134, and the opening side inclined surface 135 have different inclination angles with respect to the central axis 10 of the valve seat 1. The inclination angle of the valve seat 1 with respect to the central axis 10 increases in the order of the intermediate side inclined surface 133, the valve contact surface 134, and the opening side inclined surface 135. That is, the inclination angle θ _{1, the} inclination angle θ ₂ , and the inclination angle θ ₃ satisfy 0 ° <θ ₁ <θ ₂ <θ ₃ <90 °.

The total length H of the valve seat 1 in the valve seat axial direction is preferably about 4 (mm) or less. The length L in the valve seat axial direction from the valve seat front side end 1A to the end 134B of the valve contact surface 134 on the back opening 11 side in the valve seat axial direction is about 1.4 (mm) or less. Preferably there is. Moreover, it is preferable that the said length L is 1/2 or less of the said full length H whatever the said length L and the said full length H. In addition, the shape and dimension of each part in FIG. 3 (A) and (B) are examples. Therefore, the numerical values and ratios described above are not constrained by the shape and size of each part in FIGS. 3 (A) and 3 (B).

<Rough surface area>
The outer peripheral surface 14 of the valve seat 1 has a rough surface region 15 as shown in FIGS. The rough surface area 15 constitutes at least a part of the outer peripheral surface 14. The rough surface region 15 increases the bonding force between the valve seat 1 and the cylinder head 2, and can prevent the valve seat 1 from falling off the cylinder head 2.

In the present embodiment, the rough surface region 15 is formed in, for example, a triangular shape as seen from the direction perpendicular to the outer peripheral surface 14 as shown in FIG. Note that the triangular shape referred to here is not limited to a triangular shape in a strict sense. For example, a portion corresponding to the apex angle of the triangle may be rounded, and each side of the triangle may be rounded. A curve may be included. The rough surface area 15 is such that the apex 15D side of the triangle is the leading side (back side) of the valve seat 1 in the press-fitting direction, and the base 15F side of the triangle facing the apex 15D is the rear side (front side) of the press-fitting direction of the valve seat 1 Side). The rough surface region 15 may have any shape when viewed from the direction perpendicular to the outer peripheral surface 14, for example, a quadrangular shape (see FIG. 2B), a semicircular shape, a star shape, and the like. An example is a mold shape.

<Specific configuration of rough surface area>
Next, a specific configuration of the rough surface area 15 will be described. As shown in FIG. 3, the rough surface region 15 has an uneven portion 150. The uneven part 150 is an uneven part formed on the outer peripheral surface 14 of the valve seat 1. As shown in FIG. 4A, the concavo-convex portion 150 of the rough surface region 15 is constituted by a protrusion 151 and a recess 152 adjacent to the protrusion 151 in the valve seat axial direction (Y-axis direction). The protrusions 151 and the recesses 152 are alternately arranged along the valve seat axial direction.

5A to 5C show secondary electron images (imaging magnification: 300) of the rough surface partial areas P1 to P3, which are partial areas of the rough surface area 15 in FIG. 4A, by a scanning electron microscope. (Times). As is apparent from the photographs shown in FIGS. 4A and 5A to 5C, the protrusion 151 is outside in the radial direction of the valve seat (the side away from the paper surface in the direction perpendicular to the paper surface of FIG. 4). And is connected along the circumferential direction Q (hereinafter referred to as “valve seat circumferential direction”) Q of the outer peripheral surface 14 of the valve seat 1. On the other hand, the recessed portion 152 is a position adjacent to the protruding portion 151 in the valve seat axial direction (Y-axis direction), and is recessed inward in the valve seat radial direction (the side entering the paper surface in the direction perpendicular to the paper surface of FIG. 4). In addition, it is in a form that continues along the circumferential direction Q of the valve seat. The rough surface region 15 may include a portion without the uneven portion 150.

In the present embodiment, as shown in FIG. 4 (A), the protrusion 151 and the recess 152 are along the valve seat axial direction (Y-axis direction), and the rough surface region 15 on the back side opening 11 side in the valve seat axial direction. 15A (hereinafter referred to as the rough surface region rear side end) of the rough surface region 15 on the front opening 12 side in the valve seat axial direction (hereinafter referred to as the rough surface region front side end). )) Alternately. The rough surface area rear side end 15A corresponds to a vertex 15D of the triangle. Further, the rough surface area front side end portion 15B corresponds to the base 15F of the triangle facing the vertex 15D.

As shown in FIG. 4 (B), various protrusions 151 (depressions 152) in the concavo-convex part 150 have various heights (depths) in the valve seat radial direction. The protrusions 151 (recessed portions 152) having various heights in the valve seat radial direction are randomly arranged along the valve seat axial direction regardless of the height (depth) in the valve seat radial direction. Moreover, it is preferable that the protrusions 151 (recesses 152) having various heights (depths) in the valve seat radial direction are arranged at substantially equal intervals along the valve seat axial direction. Further, as shown in FIG. 4C, the protruding portion 151 (the recessed portion 152) in the concavo-convex portion 150 may be formed so that the height (depth) in the valve seat radial direction is the same as a whole. . Further, as shown in FIG. 4D, the protruding portion 151 (recessed portion 152) in the concavo-convex portion 150 is a valve as it progresses from the rough surface region rear side end portion 15A to the rough surface region front side end portion 15B. A mode (inclined shape) in which the height (depth) in the sheet radial direction increases may be used.

<Rough surface area formation range 1 in the valve seat axial direction>
Next, the formation range of the rough surface area 15 in the valve seat axial direction will be described with reference to FIG. The formation range of the rough surface region 15 in the valve seat axial direction will be described with reference to the position of the rough surface region rear end 15A and the position of the rough surface region front end 15B. As described above, the rough surface region 15 extends from the rough surface region rear end 15A to the rough surface region front end 15B in the valve seat axial direction.

As shown in FIGS. 3A and 3B, the rough surface area near side end 15B is located on the near side opening 12 side with respect to the position 1C. On the other hand, the rear end portion 15A of the rough surface area is 4/5 longer than the total length of the valve seat in the valve seat axial direction along the valve seat axial direction (Y-axis direction) starting from the valve seat front end 1A. It is preferably located on the back opening 11 side from the position 1E that is far away, and located on the back opening 11 side from the position 1C that is 2/3 of the total length of the valve seat in the valve seat axial direction. More preferably. In other words, the rough surface area rear side end portion 15A starts from the end portion 1B of the valve seat 1 on the back side opening 11 side in the valve seat axial direction (hereinafter referred to as the valve seat rear side end portion). It is preferably located on the back opening 11 side from the position 1E that is separated from the position 1E by a length of 1/5 of the total length of the valve seat in the valve seat axial direction along the axial direction. More preferably, it is located on the back opening 11 side rather than the position 1C that is 1/3 of the total length of the valve seat in the direction.

In the above case, the rough surface area 15 is provided so as to pass through the position 1C or the position 1E. That is, at least a part of the rough surface region 15 is provided between the position 1C and the valve seat front end 1A or between the position 1E and the valve seat front end 1A along the valve seat axial direction. It is done. If the length of the rough surface region 15 in the valve seat axial direction is the same, the rough surface region 15 provided so as to pass through the position 1C is more than the rough surface region 15 provided so as to pass through the position 1E. It can be located on the front opening 12 side.

Further, unlike the above, the rough surface area rear side end portion 15A and the rough surface area front side end portion 15B may be positioned closer to the front side opening 12 than the position 1C or the position 1E. That is, the entire rough surface region 15 may be positioned closer to the opening 12 on the near side than the position 1C or the position 1E. In this case, the entire rough surface region 15 is provided between the position 1C or the position 1E and the valve seat front end 1A along the valve seat axial direction. If the length of the rough surface region 15 in the valve seat axial direction is the same, the rough surface region 15 that is located closer to the front opening 12 than the position 1C or the position 1E passes through the position 1C or the position 1E. Can be positioned closer to the front opening 12 than the rough surface region 15 provided on the front surface.

As the valve seat 1 in the present embodiment, a thin valve seat having a small thickness in the axial direction of the valve seat is assumed. From the viewpoint of increasing the bonding force between the thin valve seat and the cylinder head 2 to prevent the thin valve seat from falling off, at least a part of the rough surface region 15 is open on the front side 12 of the outer peripheral surface 14 of the thin valve seat. It is preferable to be formed closer. For this reason, from the viewpoint of preventing the dropout, the formation range of the rough surface region 15 in the valve seat axial direction is preferably as described above.

<Rough surface area formation range 2 in the valve seat axial direction>
Further, as shown in FIGS. 3A and 3B, the rough surface area front side end portion 15B is located closer to the front side opening 12 than the position 1D. On the other hand, the rough surface area rear side end portion 15A is separated from the valve seat front side end portion 1A by the length of 1/2 of the total length of the valve seat in the valve seat axial direction along the valve seat axial direction. More preferably, it is located closer to the rear opening 11 than 1D. In other words, the rough surface area rear side end portion 15A is separated from the valve seat rear side end portion 1B by the length of ½ of the total length of the valve seat in the valve seat axial direction along the valve seat axial direction. More preferably, it is located closer to the back opening 11 than the position 1D.

In the above case, the rough surface region 15 is provided so as to pass through the position 1D. That is, at least a part of the rough surface region 15 is provided between the position 1D and the valve seat front end 1A along the valve seat axial direction. If the length of the rough surface region 15 in the valve seat axial direction is the same, the rough surface region 15 provided so as to pass through the position 1D is more than the rough surface region 15 provided so as to pass through the position 1C. It can be located on the front opening 12 side.

Further, unlike the above, the rough surface area rear side end portion 15A and the rough surface area front side end portion 15B may be positioned closer to the front side opening 12 than the position 1D. In other words, the entire rough surface region 15 may be located closer to the opening 12 on the near side than the position 1D. In this case, the entire rough surface region 15 is provided between the position 1D and the valve seat front side end portion 1A along the valve seat axial direction. If the length of the rough surface area 15 in the valve seat axial direction is the same, the rough surface area 15 that is located closer to the opening 12 side than the position 1D as a whole is provided so as to pass the position 1D. It can be positioned closer to the front opening 12 than the region 15.

<Rough surface area formation range 3 in the valve seat axial direction>
As described above, a thin valve seat having a small thickness in the axial direction of the valve seat is assumed as the valve seat 1 in the present embodiment. From the viewpoint of increasing the bonding force between the thin valve seat and the cylinder head 2, it is preferable that at least a part of the rough surface region 15 is formed near the front opening 12 of the outer peripheral surface 14 of the thin valve seat.

For this reason, as shown in FIG. 3A, the length of the axially extending surface region 130 in the valve seat axial direction is much shorter than the length of the inclined surface region 131 in the valve seat axial direction. In the case of the sheet 1, the rough surface region 15 is preferably configured to overlap only with the inclined surface region 131 in the radial direction (X-axis direction). As shown in FIG. 3B, the length of the axially extending surface region 130 in the valve seat axial direction is slightly shorter than the length of the inclined surface region 131 in the valve seat axial direction. In this case, the rough surface region 15 includes not only the inclined surface overlapping region 16A that overlaps with the inclined surface region 131 in the radial direction (X-axis direction) but also the extended surface overlapping region 16B that overlaps with the axially extending surface region 130. It may be configured to have. In any type of valve seat 1 shown in FIGS. 3A and 3B, the rough surface region 15 has a valve contact surface that overlaps the valve contact surface 134 in the radial direction (X-axis direction). It is further preferable to have the overlapping region 16C. This is because the valve contact surface 134 is a surface provided in the vicinity of the front opening 12.

<Valve seat manufacturing method>
Next, a method for manufacturing the valve seat 1 will be described with reference to FIG. First, a predetermined material is mixed (S101). Specifically, first, graphite powder and lubricant powder, alloy powder, or solid lubricant is used for iron-based powder so as to have the composition of the sintered body described in <Valve seat material>. A blend containing the agent powder and / or the hard particle powder is put into a mixing apparatus. And the said compound is mixed with a mixing apparatus and mixed powder is produced | generated.

Next, the mixed powder is put into a mold and pressure-molded to form a green compact having a predetermined shape (S102). Then, the green compact is sintered (S103). Thereby, a sintered compact is produced | generated. Sintering is preferably performed at 1100 to 1200 ° C. in a non-oxidizing atmosphere such as a reducing atmosphere or a vacuum atmosphere.

Next, the sintered body is processed to form the valve seat 1 as an annular body (S104). Examples of the processing performed here include cutting and grinding.

Then, at least a part of the outer peripheral surface 14 of the valve seat 1 processed as described above is roughened (S105). Thereby, the rough surface area | region 15 which has the uneven | corrugated | grooved part 150 in the outer peripheral surface 14 is formed. The rough surface region 15 is formed by, for example, surface processing for removing or deforming a part of the outer peripheral surface 14 of the valve seat 1.

Examples of the surface processing include, but are not limited to, processing by shot blasting, processing by laser irradiation, processing by thermal spraying, processing by sandpaper or air hammer, and the outer peripheral surface of the valve seat 1 is not limited thereto. Other surface processing capable of roughening at least a part of 14 may be used.

<Copper impregnated sintered body>
In the above, the valve seat 1 is made of a sintered body made of an iron-based sintered alloy having voids inside, but copper (Cu, the same shall apply hereinafter) is made on the sintered body made of an iron-based sintered alloy. You may comprise by the impregnated copper impregnation sintered compact. When a sintered body made of an iron-based sintered alloy is impregnated with copper, the copper enters the gap. When a sintered body made of an iron-based sintered alloy is impregnated with copper having high thermal conductivity, the copper-impregnated sintered body has high thermal conductivity, so that the thermal conductivity of the valve seat 1 can be increased. .

The inventor of the present application manufactured a copper-impregnated valve seat 1F by the above-described method for manufacturing a valve seat, using a copper-impregnated sintered body as a material. FIGS. 7A and 7B are photographs of a cross section obtained by cutting the uneven portion 150 of the rough surface region 15 of the copper-impregnated valve seat 1F in the valve seat radial direction along the valve seat axial direction.

FIG. 8 (A) is a photograph showing the distribution of copper in the copper-impregnated valve seat 1F. A white point in FIG. 8A represents copper. The white dots in FIG. 8A are distributed with a high density in the vicinity of the surface of the concavo-convex portion 150 of the rough surface region 15 of the copper-impregnated valve seat 1F and in the portion corresponding to the voids inside the copper-impregnated valve seat 1F. ing. FIG. 8B is a photograph showing the distribution of iron (Fe, hereinafter the same) in the copper-impregnated valve seat 1F. A white point in FIG. 8B represents iron. As shown in FIG. 8B, iron is distributed at a substantially uniform density throughout the copper-impregnated valve seat 1F. That is, as apparent from FIGS. 8A and 8B, it can be seen that a layer containing copper and iron is formed on at least a part of the surface of the rough surface region 15. Therefore, the rough surface region 15 can be formed also in the copper-impregnated valve seat 1F manufactured by the copper-impregnated sintered body. The description of the valve seat 1 can also be applied to the copper-impregnated valve seat 1F.

Note that the valve seat 1 may be constituted by a sintered body (hereinafter referred to as a material-impregnated sintered body) in which a sintered body made of an iron-based sintered alloy is impregnated with a material such as water glass or resin. Good. For example, when a sintered body made of an iron-based sintered alloy is impregnated with a material such as water glass or resin, the material such as water glass or resin enters a void inside the sintered body. Even when the valve seat 1 is manufactured by the above-described method for manufacturing a valve seat using the material-impregnated sintered body as a material, at least a part of the surface of the rough surface region 15 is made of a material such as water glass or resin and iron. A layer containing is formed. Similarly, when the valve seat 1 is manufactured with a material-impregnated sintered body obtained by impregnating a sintered body made of an iron-based sintered alloy with two or more kinds of materials such as copper, water glass, and resin, A layer containing two or more impregnated materials and iron is formed on at least a part of the surface of the rough surface region 15. The material impregnated in the sintered body made of iron-based sintered alloy is not limited to copper, water glass, and resin, but can be impregnated in the sintered body made of iron-based sintered alloy It may be.

<Valve seat material>
Next, with reference to FIG. 9, the valve seat material 9 (see the thick line portion in FIG. 9) that is a material before the valve seat 1 is processed will be described. In the present embodiment, the axially extending surface region of the valve seat material 9 is common to the axially extending surface region 130 of the valve seat 1. Further, in the present embodiment, the inclined surface region 131A of the valve seat material 9 is longer in the valve seat axial direction than the inclined surface region 131 of the valve seat 1, as shown in FIG. Therefore, as shown in FIG. 9, the valve seat material 9 is longer in the valve seat axial direction than the valve seat 1. Further, the inclined surface region 131A of the valve seat material 9 is composed of two inclined surfaces as shown in FIG.

The valve seat material 9 having the above configuration is subjected to material removal processing such as polishing and / or grinding after the cylinder head is press-fitted, whereby the valve seat 1 is formed.

It should be noted that all of the matters described using the valve seat 1 are also applicable to the rough surface region 15 formed in the valve seat material 9. That is, in the above description, the valve seat 1 may be appropriately replaced with the valve seat material 9.

Note that the valve seat and the valve seat material of the present invention are not limited to the above-described embodiments, and it is needless to say that various modifications can be made without departing from the scope of the present invention.

<Evaluation of high-temperature holding force of valve seat>
In order to evaluate the high temperature holding power of the valve seat of the present invention, the inventor of the present application created valve seats No. 1 to No. 17 having different conditions as shown in the table of FIG. A rough surface area is not provided in the valve seats Nos. 1 and 2. The valve seats Nos. 3 to 17 are provided with rough surface areas. The rough surface areas of the valve seats Nos. 3 to 17 are formed in a substantially triangular shape on the peripheral surface of the valve seat, as shown in FIG. The length of the bottom side of the roughly triangular rough surface region of the valve seats Nos. 3 to 16 is about 0.5 (mm), and the height (length in the valve seat axial direction) is about 0.75 (mm). (The length of the valve seat 1 is approximately ¼ of the length of the valve seat in the axial direction). For valve seat No. 17 only, the length of the base of the roughly triangular rough surface area is approximately 1.0 (mm) and the height is approximately 1.5 (mm) (the valve seat axis of the valve seat 1). The length is approximately half of the length in the direction). The rough surface areas of the valve seats Nos. 3 to 17 are formed at five equal intervals in the circumferential direction of the peripheral surface of the valve seat.

“Rough surface area near side edge position” in the table of FIG. 10A represents the edge position of the rough surface area on the near side in the press-fitting direction Y (valve seat axis direction). The thick lines 15G to 15P on the right side of the valve seat 1 in FIG. 10B represent the formation range of the rough surface regions of the valve seats Nos. 3 to 17. The thick lines 15G to 15M have a length substantially ¼ of the total length H of the valve seat 1 in the valve seat axial direction. The thick line 15N has a length shorter than the length of about ¼ of the total length H of the valve seat 1 in the valve seat axial direction. The thick line 15P has a length that is approximately ½ of the total length H of the valve seat 1 in the valve seat axial direction. The correspondence between the thick lines 15G to 15P and the valve seats Nos. 3 to 17 is described in “Valve seat No.” in the table of FIG. Specifically, the thick line 15G corresponds to the valve seat No4. The thick line 15H corresponds to valve seats Nos. 5-8. The thick line 15I corresponds to the valve seat No9. The thick line 15J corresponds to the valve seat No10. The thick line 15K corresponds to the valve seat No11. The thick line 15L corresponds to valve seats Nos. 12 to 15. The thick line 15M corresponds to the valve seat No16. The thick line 15N corresponds to the valve seat No3. The thick line 15P corresponds to the valve seat No17. Further, the thick lines 15K to 15M and the valve seats Nos. 11 to 16 correspond to the rough surface region passing through the position 1E of the <rough surface region formation range 1 in the valve seat axial direction>. Further, the thick lines 15G to 15J, 15P, and the valve corresponding to the rough surface region that is entirely located on the front opening 12 side from the position 1E of the <formation range 1 of the rough surface region in the valve seat axial direction> Sheets Nos. 4 to 10 and 17 are used. Also, the

thick lines

15J, 15K, and 15P and the valve seats Nos. 10, 11, and 17 correspond to the rough surface region that passes through the position 1C of the <rough surface region formation range 1 in the valve seat axial direction>. Further, the thick lines 15G to 15I and the valve seat No. 4 correspond to the rough surface region which is entirely located closer to the front opening 12 than the position 1C of the <formation range 1 of the rough surface region in the valve seat axial direction>. ~ 9. Further,

thick lines

15H, 15I, and 15P and valve seats Nos. 5 to 9 and 17 correspond to the rough surface region that passes through the position 1D of the <formation range 2 of the rough surface region in the valve seat axial direction>. Also, the thick line 15G and the valve seat No. 4 correspond to the rough surface region that is located entirely on the near side opening 12 side from the position 1D of the <formation range 2 of the rough surface region in the valve seat axial direction>. Note that in the valve seats (valve seats Nos. 12 to 16) whose “rough surface area near side edge position” in the table of FIG. 10A is 2/3 and 3/4, a part of the rough surface area is chamfered 14A. It takes. The radius of the chamfered portion 14A is approximately 0.5 (mm). Further, in the valve seat whose “rough surface area near side end position” in the table of FIG. 10A is 4/5, the length of the rough surface area is approximately 0.6 (mm).

10A represents the position of the end 131B of the inclined surface region 131 on the inner side in the press-fitting direction Y shown in FIG. 10B. “Valve contact surface back end position” in the table of FIG. 10A represents the position of the end portion 134B of the valve contact surface 134 on the back side in the press-fitting direction Y shown in FIG. 10B.

Note that the “rough surface region front side end position” refers to the pressure seating direction Y (valve seat axial direction) from the valve seat front side end 1A when the total length H of the valve seat 1 in the valve seat axial direction is used as a reference. The ratio of the length S1 (see FIG. 10B) in the axial direction of the valve seat up to the end position of the rough surface area on the near side (the end position 2/5 shown in FIG. 10B is an example) (S1 / H). Similarly, the “inclined surface region rear side end position” and “valve contact surface rear side end position” are also the valve seat front side end portion based on the total length H of the valve seat 1 in the valve seat axial direction. It is represented by a ratio (S2 / H, S3 / H) of lengths S2 and S3 (see FIG. 10B) in the valve seat axial direction from 1A to the corresponding positions.

“Full length” in the table of FIG. 10 (A) represents the full length H (mm) of the valve seat 1 in the valve seat axial direction shown in FIG. 10 (B). “Material dimension” in the table of FIG. 10A represents the total length J (mm) of the valve seat material 9 shown in FIG. 10B in the valve seat axial direction.

Then, the inventor sets valve seats No. 1 to 17 in the high-temperature holding force measuring apparatus 200 shown in FIG. 11, and sets the withdrawal load (high-temperature escape load) of the valve seats No. 1 to 17 at a predetermined temperature (approximately 200 ° C.). It was measured. As shown in FIG. 11, the high-temperature holding force measuring apparatus 200 includes a cylinder head equivalent member 210 corresponding to a cylinder head, a heating part 220, a pressing part 230, and a load meter 240. The valve seat 1 is press-fitted into the cylinder head equivalent member 210 as shown in FIG. The heating unit 220 heats the valve seat 1 press-fitted into the cylinder head equivalent member 210 to a predetermined temperature (approximately 200 ° C.). The pressing unit 230 presses the valve seat 1 and separates it from the cylinder head equivalent member 210. The load meter 240 measures the load T applied to the valve seat 1 by the pressing unit 230. The load when the valve seat 1 is detached from the cylinder head equivalent member 210 corresponds to the escape load.

The “load ratio” in the table of FIG. 10A corresponds to the slip-out loads T _n of the other valve seats Nos. 2 to 17 (n is the valve seat No.) with reference to the slip-out load T ₁ of the valve seat No. 1. (Number) ratio (T _n / T ₁ ).

Valve seats Nos. 1 to 3 are created as comparative examples. The valve seat No. 1 is not provided with a rough surface area, and the total length H is approximately 3 (mm). Moreover, valve seat No2 is a thing in which the rough surface area | region is not provided, and the full length H is about 4 (mm). The valve seat No. 3 is provided with a rough surface area, but the “rough surface area near side end position” is 4/5, and the length of the rough surface area is approximately 0.6 (mm).

Looking at the “load ratio” in the table of FIG. 10 (A), valve seats Nos. 4 to 11 having a “rough surface area front side end position” of 3/5 or less (see thick lines 15G to 15K in FIG. 10 (B)). Then, the load ratio exceeds 2, and it can be seen that, particularly when the valve seat is detached from the cylinder head, a large pull-out load is required. Therefore, it can be said that the valve seats Nos. 4 to 11 have particularly excellent high-temperature holding power.

Further, in the valve seats Nos. 12 to 16 (refer to the

thick lines

15L and 15M in FIG. 10B) in which the “rough surface region front side end position” is in the range of 2/3 to 3/4, the load ratio is 1.2. It can be seen that a large pull-out load is required when the valve seat is detached from the cylinder head. In the valve seats Nos. 12 to 15 (refer to the thick line 15L in FIG. 10B) having a “rough surface area near side end position” of 2/3, the load ratio exceeds 1.4, and the distance from the cylinder head It can be seen that, in the separation of the valve seat, a larger pull-out load is required than in the case of the valve seat No. 16 (see the thick line 15M in FIG. 10B). For this reason, it can be said that the valve seats Nos. 12 to 16 have excellent high-temperature holding power, and among them, the valve seats No. 12 to 15 can be said to have superior high-temperature holding power.

Further, in the valve seat No. 3 (refer to the thick line 15N in FIG. 10B) having a “rough surface region near side end portion position” of 4/5, the load ratio is 1.04 and the valve without the rough surface region is provided. It has slightly higher temperature holding power than sheet No1. Looking at the measurement results for valve seat No. 3 and valve seat Nos. 12 to 16, the load increases as the “rough surface area near side edge position” moves further toward the near side in the press-fitting direction Y (valve seat axial direction) than 4/5. The ratio is getting bigger. Therefore, if the “rough surface region near side end position” of the rough surface region is 4/5 or less, it can be said that a large pull-out load is required for detachment of the valve seat from the cylinder head.

Further, the valve seat No. 17 has a “rough surface area near side end position” of 1/4 (“rough surface area rear side edge position” is 3/4), and the valve seat axial direction of the rough surface area Is approximately 1.5 (mm) (approximately 1/2 the length of the valve seat 1 in the valve seat axial direction), and the length of the bottom of the rough surface region is approximately 1.0 (mm). (See the thick line 15P in FIG. 10B). In the valve seat No. 17, the load ratio exceeds 3, and an extremely large pull-out load is required when the valve seat is detached from the cylinder head. For this reason, valve seat No17 has the extremely excellent high temperature holding power.

Summarizing the above results, when the “rough surface area near side edge position” advances toward the near side in the press-fitting direction Y (valve seat axial direction), a larger pull-out load is required for detachment of the valve seat from the cylinder head. It can be said that This provides a valve seat that can efficiently press-fit into the cylinder head even when the position where the structure that does not easily fall off from the cylinder head for the internal combustion engine reaches the front side (rear side) of the press-fitting direction of the valve seat can do.

1 Valve Seat 1A Valve Seat Front End 1B Valve Seat Back End 1F Copper Impregnated Valve Seat 2 Cylinder Head 7 Valve 8 Holding Area 8A Contact Surface 9 Valve Seat Material 10 Center Axis 11 Back Opening 12 Front Opening 13 Inner peripheral surface 14 Outer peripheral surface 15 Rough surface region 15A Rough surface region rear end 15B Rough surface region near end 16A Inclined surface overlapping region 16B Extended surface overlapping region 16C Valve per surface overlapping region 130 Axial extending

surface region

131, 131A Inclined surface area 132 Axial extending surface 133 Intermediate inclined surface 134 Valve contact surface 135 Opening inclined surface 150 Concavity and convexity 151 Projection portion 152 Depression portion H Total length Q Valve seat circumferential direction Y Press-fit direction

Claims

A valve seat press-fitted into a cylinder head for an internal combustion engine and in contact with the valve;
A rough surface region having an uneven portion on the outer peripheral surface of the valve seat,
At least a part of the rough surface area starts from an end portion of the valve seat on the near side in the press-fitting direction in which the valve seat is press-fitted into the cylinder head (hereinafter referred to as a valve seat near-side end portion). Along the press-fitting direction, the valve seat is provided within a range of a length of 4/5 of the total length of the valve seat,
Valve seat.
At least a part of the rough surface area is provided within a range of 2/3 of the total length of the valve seat in the press-fitting direction along the press-fitting direction starting from the front end of the valve seat. Characterized by
The valve seat according to claim 1.
At least a part of the rough surface area is provided within a range of ½ of the total length of the valve seat in the press-fitting direction along the press-fitting direction starting from the front end of the valve seat. Characterized by
The valve seat according to claim 1.
The inner peripheral surface of the valve seat has an inclined surface region having at least one inclined surface inclined with respect to the press-fitting direction,
The rough surface region has an overlapping region that overlaps the inclined surface region in the radial direction of the valve seat,
The valve seat according to any one of claims 1 to 3.
The inclined surface area has a valve contact surface that contacts the valve;
The length in the press-fitting direction from the end on the valve seat front side to the end on the back side in the press-fitting direction on the valve contact surface is approximately 1.4 mm or less,
The valve seat according to claim 4.
The inclined surface area has a valve contact surface that contacts the valve;
The length in the press-fitting direction from the valve seat front side end to the end of the valve contact surface in the press-fitting direction is not more than ½ of the total length of the valve seat in the press-fitting direction. Features
The valve seat according to claim 4.
The total length of the valve seat in the press-fitting direction is approximately 4 mm or less,
The valve seat according to any one of claims 1 to 6.
A valve seat material that is a material before being processed into a valve seat that is press-fitted into a cylinder head for an internal combustion engine and contacts the valve,
A rough surface region having an uneven portion on the outer peripheral surface of the valve seat material,
At least a part of the rough surface region is an end portion of the valve seat material corresponding to the front side in the press-fitting direction in which the valve seat is press-fitted into the cylinder head (hereinafter referred to as a valve seat material front side end portion). As a starting point, and is provided within a range of 4/5 of the total length of the valve seat material in the press-fitting direction along the press-fitting direction.
Valve seat material.
At least a part of the rough surface area is provided within a range of 2/3 of the total length of the valve seat material in the press-fitting direction along the press-fitting direction starting from the front end portion of the valve seat material. It is characterized by being
The valve seat material according to claim 8.
At least a part of the rough surface area is provided within a range of half the total length of the valve seat material in the press-fitting direction along the press-fitting direction starting from the front end portion of the valve seat material. It is characterized by being
The valve seat material according to claim 8.
The inner peripheral surface of the valve seat material has an inclined surface region having at least one inclined surface inclined with respect to the press-fitting direction,
The rough surface region has an overlapping region that overlaps the inclined surface region in the radial direction of the valve seat material,
The valve seat material according to any one of claims 8 to 10.