JP2003136256A - Rotary tool for friction stir and processing method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary tool for friction stir which not only secures a desirable processing depth but also performs friction stir in a relatively narrow area and to provide a friction stir processing method using the rotary tool. SOLUTION: This rotary tool for friction stir is provided with a tool body 21 which is nearly pillar-shaped, a tool tip 22 having a conically tapered part 24 which is coaxially disposed on the tip side of the tool body and is tapered, and a groove 25 which is spirally formed on the surface of the conically tapered part of the tool tip and set in such a manner that a peripheral shape in a longitudinal section containing an axial line Lb of the tool body becomes nearly a V-shape. Therein, the groove is set in such a manner that the area of an opposite-inserting side slant face is made to be the area of inserting side slant face or larger, and the rotary tool is used by rotating the tool tip inversely to the screwing direction of the nearly V-shaped groove which is spirally formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called friction stir rotating tool used for so-called friction stir processing, and a processing method for performing friction stir processing on a member made of a light metal such as an aluminum alloy using the tool. .

[0002]

2. Description of the Related Art As is well known, a cylinder head of an engine for a vehicle such as an automobile is generally made of a cast product using a light alloy material such as aluminum (Al) or its alloy. Then, the cylinder head is assembled to the cylinder block for use.

In such a cylinder head, the so-called
Referred to as "valve bridge part" or "intervalve part",
In the region between the port holes of the intake and exhaust ports, the volume expansion due to the combustion in the cylinder when the engine is driven and the volume contraction due to the cooling when the engine is stopped are repeated, and therefore cracks due to thermal fatigue are generally likely to occur. In order to solve this problem, conventionally, it is known as a general method to perform so-called remelting treatment on the intervalve portion to improve the thermal fatigue strength.

However, this remelting process is intended to melt (remelt) and solidify the base material in a limited area as a processing target, and to stabilize the required processing depth and the refinement effect of the metal structure. It is actually difficult to obtain, and the problem of high temperature oxidation accompanying the remelting process is unavoidable, and further, there are problems that unfilled defects such as pinholes and defects such as cracks easily occur, and these are avoided. In order to do so, application of a shield gas, preheating and / or post heat treatment, etc. are required, resulting in high cost, and in fact, various problems are involved in terms of ensuring quality and productivity.

Therefore, in recent years, aluminum (Al) has been used.
It is considered to apply a so-called friction stir treatment to the surface modification treatment of a light metal member such as magnesium, magnesium (Mg), or an alloy thereof. For example, the applicant of the present application proposed in Japanese Patent Application No. 2000-393328 to apply such a friction stir processing method to a surface modification treatment of an intervalve portion of an Al alloy cylinder head of a four-cylinder diesel engine. Further, although the intervalve surface is not modified, for example, in JP-A-2000-15426, for surface treatment of a seal surface (a mating surface) of a cylinder block of an Al alloy cylinder head of an engine, It is disclosed that such a friction stir processing method is applied.

In this friction stir processing method, a rotating tool rotating at a high speed is brought into contact with and pressed against the surface of the member, and the frictional heat generated at that time and the stirring action of the rotating body cause the rotating tool contact portion on the surface of the member. And the region in the vicinity thereof are softened to cause plastic flow. Then, the material portion in the plastic state (plastic fluidized bed) is agitated in a non-molten state, and thereafter the plastic fluidized portion is solidified, so that the surface of the member and a region in the vicinity thereof are modified.

On the surface of a cast member made of a light metal such as Al alloy,
By performing the surface modification treatment by this friction stir processing, the metal structure of the surface portion of the cast member is made more dense as compared with the case of the so-called remelt treatment or the like in which the surface portion is melted and modified, and It is possible to significantly reduce internal unfilled defects due to porosity, and improve mechanical properties such as elongation and toughness and fatigue strength (thermal fatigue strength). In this case, there is no possibility that blowholes or pinholes will be formed by gas or the like inside the cast member, as in the case of reforming by melting the surface portion by remelting treatment or the like.

The friction stir method is not only used for surface modification of light metal members, but also when, for example, relatively thin light metal plate members are abutted to each other and the two plate members are joined at the abutting portion (for example, patent In the case of joining light metal members to each other (see Japanese Patent No. 2712838), it is also useful as a joining method capable of joining light metal members without melting the base metal of the joining portion, instead of the conventional welding method.

By the way, the rotary tool used in the friction stir method is integrally fixed to a tool main body 61 made of a cylindrical body having a predetermined diameter and a central portion of its tip as shown in FIGS. 20 and 21, for example. Conventionally, a probe portion 62 formed of a cylindrical body having a predetermined length and a relatively small diameter (compared to the tool body portion 61) is conventionally used.

In this conventional rotary tool 60, the area of the end surface of the tool body 61 excluding the probe portion 62 is
The so-called shoulder portion 63 is configured, and during the friction stir processing, the shoulder portion 63 presses the friction stir portion of the processing target member 51 from the surface side, and the plastic fluidized layer of the portion rises to the surface side. By restricting the deformation, it is possible to suppress the deformation of the processing target member 51 on the surface 51f side.

The tool body 61 is supported by a holder (not shown) so as to be rotatable about its axis. By rotating this holder (not shown) by tool driving means 65, the rotary tool 60 is rotated. Can be rotated around. Although not specifically shown, the tool driving means 65 includes a rotary tool 60 via a holder (not shown).
Is provided with a drive motor for rotating the rotary tool 60 at a high speed, and the rotary tool 60 is mounted on the surface 51f of the processing target member 51.
And a driving mechanism for driving the member surface 51f substantially vertically (that is, in the vertical direction in FIGS. 20 and 21). Then, by driving the driving means 65, the probe portion 62 and the shoulder portion 63 of the rotary tool 60 in the high-speed rotation state with respect to the processing target member 51 in a direction substantially perpendicular to the surface 51f thereof (that is, the member 51). It can be made to enter (in the depth direction) and can be moved substantially along the member surface 51f.

[0012]

However, in the conventional rotary tool 60 described above, the base end side of the probe portion 62 constitutes the shoulder portion 63, and the probe portion 62 is used during the friction stir processing.
Not only this, but also the shoulder portion 63 is rotated in a state of abutting and being pressed against the surface portion 51f of the processing target member 51, so that the shoulder portion 63 is incidental (that is, unnecessary) by the friction stirring action of the shoulder portion 63. ) There is a problem that the plastic fluidized bed 53 is generated and the processing width becomes wider than necessary.

Therefore, for example, in the case where the surface modification treatment is applied to a portion having a limited treatment width such as the above-mentioned cylinder head valve portion (see FIG. 21), the conventional rotary tool 60 is used. Then, due to the additional (unnecessary) plastic fluidized layer 53 caused by the frictional rotation action of the shoulder portion 63, the treated portion is deformed due to shoulder sag, and in some cases, an unfilled defect is caused. There is a fear that such problems will occur.

Further, when the finishing processing by machining is performed after the surface modification treatment because the processing width becomes too wide, the machining allowance ΔMw in this finishing processing (see FIG. 21).
However, there is also a problem that the production efficiency becomes low and the production efficiency decreases. In FIG. 21, the solid line display of the processing target member 51 indicates the state of the base material during the friction stir processing, and the two-dot chain line display indicates
The finished state by machining after processing is shown. Furthermore,
Even when the light metal members are joined together by the friction stir method, the conventional rotary tool 60 has a drawback that the joining width becomes wider than necessary.

In Japanese Patent Laid-Open No. 11-128083, a screw is formed on the outer peripheral surface of the probe portion to rotate the tool body in a direction opposite to the spiral direction of the screw in order to improve the friction stirring effect. Although a friction stir tool of the type described above is disclosed, even in this case, the same as that shown in FIGS. 20 and 21 is provided on the base end side of the probe portion (the tip end side of the tool main body portion). A shoulder portion is provided, and the friction stirring portion of the processing target member is pressed from the surface side by the shoulder portion, and the plastic fluidized bed of the portion is prevented from rising to the surface side.

The present invention has been made in view of the above problems, and provides a rotary tool for friction stirrer capable of frictionally stirring a relatively narrow range while ensuring a required processing depth, and It is a basic object to provide a friction stir processing method using such a rotary tool.

[0017]

In order to achieve the above object, the inventor of the present application has made various researches and developments to form a screw on the outer peripheral surface of the probe portion so that the tool is opposite to the spiral direction of the screw. In a friction stir tool of the type designed to be driven to rotate in the same direction, the cross-sectional shape of the screw is variously examined, and it is more preferable that the area of the anti-insertion side slope is equal to or greater than the insertion side slope. When the area of the insertion side slope is set to be larger than the area of the insertion side slope, when the tool is rotated to perform friction stirring, the friction stirring portion of the processing target member is not pressed by the shoulder portion, It was found that the rise of the plastic fluidized bed on the surface side is effectively suppressed.

This is because the plastic fluidized bed formed in and near the thread groove by friction stirring is rotated by the tool in the direction opposite to the spiral direction of the screw (that is, the screwing direction), and The anti-insertion side slope may suppress the flow of the tool to the anti-insertion side (that is, the surface side of the processing target member). However, the area of the anti-insertion side slope of this screw groove should be at least the area of the insertion side slope. It is considered that this is because the effect of suppressing the flow of the plastic fluidized layer to the non-insertion side is further increased by setting it to be larger than the area of the insertion-side inclined surface.

In particular, by providing the tapered conical taper portion on the probe portion and providing the screw (spiral V-shaped groove) having the above-described shape on the outer peripheral surface thereof, the processing width can be made narrower.
Moreover, they have found that the treatment depth can be made deeper, and moreover, the swelling of the plastic fluidized bed on the surface side can be suppressed more effectively.

Therefore, the rotary tool for friction stirrer according to the first aspect of the present invention has a tool tip having a substantially columnar tool body and a tapered conical taper portion provided coaxially on the tip side of the tool body. Part and a groove part which is provided spirally on the surface of the conical taper part of the tool tip part and whose peripheral shape in a vertical cross section including the axis of the tool body part is set to a substantially V shape, the groove part being on the opposite side to the insertion side. The inclined surface area is set to be equal to or larger than the insertion side inclined surface area, and the tool tip portion is used by rotating it in the direction opposite to the screw-in direction of the substantially V-shaped groove portion provided in the spiral shape. It is characterized by. In this case, it is more preferable that the groove is set such that the area of the non-insertion side slope is larger than the area of the insertion side slope.

The invention according to claim 2 of the present application is a tool body having a substantially columnar shape, a tool tip having a tapered conical taper provided coaxially on the tip side of the tool body, and the tool tip. Groove provided in a spiral shape on the surface of the conical taper portion and having a peripheral shape in a vertical cross section including the axis of the tool main body set to a substantially V shape, and a groove passing through the bottom of the groove in the vertical cross section. The angle formed by the center line of the bottom and the axis orthogonal to the axis of the tool body is set to be less than or equal to the inclination angle of the conical taper with respect to the axis of the tool body, and the tool tip is provided in the spiral shape. It is characterized in that it is used by rotating it in a direction opposite to the screw-in direction of the substantially V-shaped groove. In this case, it is more preferable that the angle formed by the groove bottom center line and the axis orthogonal line is set to be less than the inclination angle of the conical taper portion with respect to the tool body axis.

Furthermore, in the invention of claim 3 of the present application, in the invention of claim 2, in the longitudinal section including the axis of the tool body, the center line of the groove bottom passing through the bottom of the groove and the axis of the tool body are defined. It is characterized in that the angle formed by the orthogonal axes is set to substantially zero degree.

Further, the invention according to claim 4 of the present application provides the method of joining light metal members by a friction stir method.
It is characterized in that the rotary tool described in any one of 1 to 3 is used to perform friction stir processing on the joint portion between the light metal members.

Furthermore, the invention of claim 5 of the present application is the rotary tool according to any one of claims 1 to 3 when the surface modification treatment is applied to a predetermined surface portion of the light metal member by a friction stir method. Is used to perform friction stir processing on a predetermined surface portion of the light metal member.

Further, the invention of claim 6 is the invention of claim 5, wherein the light metal member is an engine cylinder head made of cast aluminum alloy, and the predetermined surface portion is a surface portion between intake and exhaust ports. It is characterized by being.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. 1 and 2 are a front view and a bottom view of a friction stirrer rotary tool according to the present embodiment. As shown in these drawings, the rotary tool 10 includes a tool main body 11 that is formed of a coaxial multi-stage cylinder and is substantially cylindrical as a whole, and a tool tip 12 that is provided on the tip side of the main body 11. And the central axis of the tool tip 12 is the central axis (axis) of the tool body 11.
It is configured to match Lb.

As shown in detail in FIG. 3, the tip end portion 13 of the tool tip portion 12 is formed of a part of a spherical surface having a predetermined radius of curvature Rs, and has a curved surface shape of a circle having a diameter Ds in bottom view. Has been formed. Further, the side surface portion of the tool tip portion 12 is configured by a so-called tapered conical taper portion 14 having a smaller diameter toward the tip.

A screw-shaped groove portion 15 is provided on the surface of the conical taper portion 14. This groove 15
Is the axis Lb of the tool body 11 as shown in detail in FIG.
The peripheral shape in the vertical section including is set to a substantially V shape,
The conical taper portion 14 is spirally provided on the surface at a predetermined pitch p.

The conical taper portion 14 provided with the screw-shaped groove portion 15 is provided over the length Hg from the tip of the tool tip portion 12, and the base end portion of the conical taper portion 14 and the end portion of the tool body portion 11 are provided. Are connected by a tapered surface having a larger inclination angle than the conical tapered portion 14. That is, in this rotary tool 10, a flat shoulder portion is not provided on the lower end side of the tool body as in the conventional case.

Further, in the present embodiment, in the longitudinal section including the axis L1 of the tool body 11, the groove bottom center line Lv passing through the bottom of the groove 15 and the axis Lb of the tool body 11 are passed.
The cross-sectional shape of the V-shaped groove portion 15 is set such that the angle α formed by the axis orthogonal line Ly that is orthogonal to the angle α is equal to or less than the inclination angle β of the conical taper portion 14 with respect to the tool body portion axis Lb.

That is, as indicated by the solid line in FIG. 4, the angle α1 formed by the groove bottom center line Lv and the axis orthogonal line Ly is equal to the inclination angle β1 of the conical taper portion 14 (α1).
= Β1), the groove bottom center line Lv is the conical taper portion 1
4 is perpendicular to the surface of the groove 4, and the area of the upper (anti-insertion side) slope 15a of the groove 15 is equal to the area of the lower (insertion side) slope 15b. However, when the angle α formed by the groove bottom center line Lv and the axis orthogonal line Ly is larger than the inclination angle β of the conical taper portion 14 (α> β), the upper (anti-insertion side) slope of the groove portion 15 is The area is smaller than the area of the lower (insertion side) slope.

On the other hand, as shown by the broken line in FIG. 4, the angle α2 formed by the groove bottom center line Lv and the axis orthogonal line Ly is less than the inclination angle β1 of the conical taper portion 14 (α2 <
In the case of β1), the groove bottom center line Lv is the conical taper portion 14
And the angle γ (groove angle) formed by the upper slope 15a and the lower slope 15b of the groove portion 15 is constant,
The area of the upper slope 15a is larger than the area of the lower slope 15b.

Therefore, in this case, the tool tip portion 12 is rotated in the direction opposite to the screw-in direction (that is, the spiral direction) of the substantially V-shaped groove portion 15 provided in the spiral shape to perform frictional stirring. Tool tip 1 in high speed rotation
When 2 is pressed into the surface of the member to be treated and made to enter, the side opposite to the plastic fluidized layer side (upper side in FIGS. 3 and 4) of the plastic fluidized layer generated in and near the groove 15 by friction stirring.
Therefore, it is possible to effectively suppress the rise of the plastic fluidized bed on the surface side without pressing the friction stir portion of the object to be treated with the shoulder portion unlike the conventional case.

That is, the above-mentioned problems that may occur when using a conventional rotary tool accompanied by unnecessary friction stirring by the shoulder portion provided on the lower end side of the tool body can be solved, and a required processing depth can be ensured. With this, frictional stirring can be performed in a relatively narrow range. Moreover, the tool tip 12
Has a tapered conical taper portion 14, and the substantially V-shaped groove portion 15 is provided spirally on the surface of the conical taper portion 14, so that the processing width during friction stirring is narrower and The depth can be made deeper and moreover, the swelling of the plastic fluidized bed on the surface side can be suppressed more effectively. still,
As the tool driving means for driving the rotary tool 10 according to this embodiment, for example, the same tool driving means 65 as shown in FIG. 20 can be used.

Next, a rotary tool for friction stirrer according to a second embodiment of the present invention will be described with reference to FIG. In the following description, the rotary tool 10 according to the above-described first embodiment (hereinafter, appropriately referred to as a “type I” rotary tool) has the same configuration and has the same operation. The same reference numerals are given to the components that form, and further description is omitted.

Rotary tool 20 according to the second embodiment
(Hereinafter, this is appropriately referred to as a “type II” rotary tool.) The shapes of the tool body portion 21 and the tool tip portion 22 (including the tip portion 23 and the side conical taper portion 24) are as follows. The same as in the first embodiment, but the angle formed by the groove center line Lv of the V-shaped groove 25 formed on the surface of the conical taper portion 24 and the axis orthogonal line Ly as described below. α has a different setting.

That is, as shown in FIG. 3, the groove bottom center line Lv of the substantially V-shaped groove portion 15 and the axis orthogonal line Ly.
Is set to be less than the inclination angle β of the conical tapered portion 14 (α <β), the area of the upper (anti-insertion side) slope 15a becomes larger than the area of the lower (insertion side) slope 15b. In such a setting, as in the rotary tool 20 shown in FIG. 5, the angle α formed by the groove bottom center line Lv and the axis orthogonal line Ly is set to substantially zero degree so that the screw is screwed in the same direction. With respect to the substantially V-shaped groove portion 25, the area of the non-insertion side inclined surface can be substantially maximized, and a higher effect can be achieved.

In order to confirm the effect of the present invention, the rotary tool of the example of the present invention and the rotary tool of the comparative example were respectively used,
A surface modification treatment was performed on the surface portion of the sample member to be treated by friction stirring, and a comparative test (test 1) was conducted to examine the aspect of the treated portion. FIG. 6 is a front explanatory view of the rotary tool 40 according to the comparative example used in the main test 1. In the rotary tool 40 of this comparative example, a cylindrical tool body 41 (diameter = 25 m
m) a cylindrical tool tip 42 (diameter =
7.0 mm; length = 6.0 mm), and a region of the end surface of the tool main body 41 excluding the tool tip 42 constitutes a shoulder 43.

On the side surface of the tool tip portion 42, a groove portion (groove angle = 60 degrees; pitch = 1 mm) having a substantially V-shaped cross section is provided in a screw shape (spiral shape). Then, the tool 40 is rotated in the direction opposite to the spiral direction to perform the friction stir processing.

On the other hand, as the rotary tool according to the embodiment of the present invention, the type (type I) according to the second embodiment is used.
(I: see FIG. 5) was used. Specific dimensional values and the like of each part shown in FIG. 5 are as follows. -Diameter of the tip 23 of the tool tip 22: Ds = 7 mm-Length of the conical taper 24: Hg = 5.8 mm-Radius of curvature of the tip 23: Rs = 6 mm-Pitch of the groove 25: p = 1 mm-Angle of groove bottom center line Lv with respect to axis orthogonal line Ly: α = 0
Degree / Inclination angle of conical taper portion 24: β = 15 degrees / Groove angle of groove portion 25: γ = 60 degrees

The rotary tools 20 and 40 are both
It is manufactured by using a so-called tool steel defined in JIS as a material and subjecting it to necessary machining and heat treatment. The member to be treated in this test is a cast member made of an aluminum alloy defined by JIS standard, and for example, an Al alloy AC4D often used for an engine cylinder head or the like.
Was used as the material. Friction stir processing was performed using each of the above two types of rotary tools 20, 40, and the processing results were compared. The friction stir processing conditions for each rotary tool are:
Each is as follows.

[0042] -Comparative example: tool rotation speed = 1200 rpm         : Tool moving speed = 32 mm / min. Inventive Example (Type II): Tool Rotational Speed = 1080 rpm                           : Tool moving speed = 75 mm / min.

For each test material after the friction stir processing was completed,
The depth and processing width of the friction stir processing part (modified layer) were examined and compared. That is, after the friction stir processing was completed, the treated portion of each test material was cut, the cut surface was polished, and then the depth and width of the modified layer were observed with a projector at a magnification of about 5 times. . The observation results are shown in FIG. 8 (Example of the present invention) and FIG. 9 (Comparative example).

As can be seen by comparing FIGS. 8 and 9, the width of the friction stir processing section Sf is extremely wide in the case of the comparative example with respect to substantially the same processing depth. In addition, in the case of the comparative example, although the tool moving speed is half or less of that of the embodiment of the present invention as described above, many missing portions B are generated on the surface of the processing portion Sf, and the surface side during friction stirring. It shows that there is a large amount of plastic flow that has flowed to the surface and was washed away as burr. In FIGS. 8 and 9 and FIGS. 10 to 18 described later, the above-mentioned missing portion B generated in the friction stir processing unit Sf is shown as a region displayed in black.

In other words, the rotary tool 20 according to the embodiment of the present invention.
By using (Type II), the processing width of the friction stir processing is narrower (with respect to the equivalent processing depth) and the processing depth is smaller than that when the rotary tool 40 of the comparative example is used. It was confirmed that the depth can be made deeper (for an equivalent treatment width), and moreover, swelling deformation due to flow to the surface side of the plastic fluidized bed and generation of a large amount of burrs can be suppressed more effectively.

Next, the rotary tool 10 (type I) according to the first embodiment and the rotary tool 20 (type II) according to the second embodiment are rubbed against the surface portion of the sample member to be treated. A surface modification treatment was performed by stirring, and a comparative test (Test 2) was conducted to examine the aspect of the treated portion. The rotary tools 10 and 20 described above differ only in the value of the angle α of the groove bottom center line Lv with respect to the axis orthogonal line Ly, and the other dimensional values are the same. The angle α is as follows.・ Type I: Angle α = 15 degrees ・ Type II: Angle α = 0 degrees

Further, the concrete dimensional values and the like of each part shown in FIGS. 4 and 5 are as follows. -Diameter of the tip portions 13 and 23 of the tool tip portions 12 and 22:
Ds = 7 mm-Conical taper parts 14 and 24 length: Hg = 5.8 mm-Curvical radius of the most distal end parts 13 and 23: Rs = 6 mm-Pitch of groove parts 15 and 25: p = 1 mm-Conical taper part 14, Inclination angle of 24: β = 15 degrees / Groove angle of groove portions 15 and 25: γ = 60 degrees

In this test 2, for both rotary tools 10 and 20, the conditions of the tool rotation speed and the amount of indentation with respect to the member to be processed were kept constant at the following values, and the moving speed of the tool was variously changed to perform friction stir processing. It was A light alloy member similar to that used in Test 1 was used as a member to be treated. -Tool rotation speed (constant): 1080 rpm-Pushing amount (constant): 5.5 mm-Tool movement speed (processing speed: constant): 22.5, 70, 150, 320, 470, 750 [mm / min. ]

For each test material after the completion of the friction stir processing,
In the same manner as in the case of Test 1, the depth and the treatment width of the friction stir processing portion (modified layer) were investigated and comparatively examined. The test results of this test 2 are shown in Table 1 and FIGS.

[0050]

[Table 1]

As shown in Table 1, in the comparative examination of the test results of this test 2, there was a large amount of missing portion B in the surface layer of the treated part due to the flow and outflow of the plastic fluidized bed Sf to the treated surface side. Those that could not be removed sufficiently by the finishing process of the process were rejected (marked with X), and the missing part B of the surface layer of the treated part was small and could be reliably removed by the finishing process of the subsequent process. Regarding, the result was marked (marked with ○). Table 1
As can be seen from FIGS. 10 to 12, the processing speed is 22.5 mm / m in the case of the type I rotary tool 10.
in. In the case of (see FIG. 10), it was acceptable, and at the processing speeds exceeding it (70, 150 mm / min .: see FIGS. 11 and 12), it was not acceptable. Incidentally, in the case of this type I rotary tool 10, 320 mm / min. The above processing speed was not intentionally tested because the results are clear.

On the other hand, the type II rotary tool 20
In the case of, the processing speed was 320 mm / min. The following cases (see FIGS. 13, 14, 15 and 16) were all acceptable, and processing speeds exceeding them (470 and 750 mm / m).
in. : See FIGS. 17 and 18).

Both of the rotary tools 10 and 20 described above are provided with conical taper portions 14 and 24 on the tool tip portions 12 and 22, respectively, and substantially V-shaped groove portions 15 and 25 are spirally formed on the outer peripheral portions thereof. The inclination angle β of the conical taper portions 14 and 24 with respect to the tool body portion axis Lb is 15 degrees. However, regarding the angle α formed by the groove bottom center line Lv and the axis orthogonal line Ly, in the case of the rotary tool 10 (type I), the conical taper portion 1
Equal to the tilt angle β of 4 (α = β = 15 degrees),
The area of the slope on the opposite side of the groove 15 and the area of the slope on the side of insertion are equal.

Therefore, in this type I rotary tool 10, when the tool tip portion 12 in the high-speed rotation state is pushed into the surface portion of the member to be treated and is made to enter, the friction stirrer causes the inside of the groove portion 15 and the vicinity thereof. It is difficult to sufficiently suppress the flow to the anti-insertion side (that is, the treated surface side) of the plastic fluidized layer that has occurred at the anti-insertion side slope of the groove portion 15, and since the shoulder portion is not originally provided, Processing speed is 70 mm / min. Above a certain level, it is difficult to sufficiently control the flow and outflow of the plastic fluidized bed to the treated surface side. The test results in Table 1 and FIGS. 10 to 12 demonstrate this fact.

Even when this type I rotary tool 10 is used, as can be seen by comparing FIG. 9 and FIG. 10, as compared with the case where the friction stir processing is performed using the rotary tool 40 of the comparative example. Then, the processing width of the friction stir processing can be made narrower (for the equivalent processing depth), and the processing depth can be made deeper (for the equivalent processing width). Further, it is possible to more effectively suppress the swelling deformation and the generation of a large amount of burrs due to the flow to the surface side of the plastic fluidized bed.

In the case of the rotary tool 20 (type II) with respect to the rotary tool 10 of type I, the angle α formed by the groove bottom center line Lv and the axis orthogonal line Ly is larger than the inclination angle β of the conical taper portion 24. Small (α <β), and this angle α = 0
Since the groove 25 is set at a degree, the area of the non-insertion side slope of the groove 25 is larger than the area of the insertion side slope and is maximized.

Therefore, in the case of this type II rotary tool 20, the tool tip portion 22 is rotated in a direction opposite to the screw-in direction (that is, the spiral direction) of the substantially V-shaped groove portion 25 provided in a spiral shape to cause friction. By stirring, the tool tip portion 22 in the high-speed rotation state is pressed against the surface portion of the processing target member to enter the surface portion of the processing target member. The effect of suppressing the flow to the insertion side (that is, the processing surface side) becomes greater, and the flow to the non-insertion side of the plastic fluidized bed does not have to be held down by the shoulder part of the friction stirrer part of the object to be processed unlike the conventional case. , The slope of the groove 25 on the side opposite to the insertion side can sufficiently suppress, and the processing speed is relatively high (320 mm / m 2).
in. Even in the case of (degree), the flow and outflow to the treated surface side of the plastic fluidized bed can be sufficiently regulated. The test results shown in Table 1 and FIGS. 13 to 18 show this fact.

Next, regarding a specific example of performing the friction stir processing by using the rotary tool 20 (type II) according to the embodiment of the present invention, for example, the modification processing of the surface portion of the intervalve portion in the cylinder head of the engine is performed. The case of performing will be described as an example. FIG. 19 is a plan view schematically showing a mating surface of the cylinder head casting material according to the first embodiment with a cylinder block (not shown). As shown in this figure, the cylinder head CH is for a direct injection diesel engine of the in-line four-cylinder type, and has a pair of intake ports K for each cylinder arranged in a line along the longitudinal direction.
c and a pair of exhaust ports Ec are provided. And the member area between the ports for each cylinder (that is, the valve area)
Form a cross shape.

The cylinder head CH is manufactured by a casting process using, for example, an aluminum (Al) alloy as a material, and the surface to be mated with the cylinder block (not shown), particularly the valve portion, is subjected to the surface treatment by the above-mentioned friction stir processing method. Is given. The light alloy material of the cylinder head CH is, for example, an Al alloy AC4D specified in JIS standard.
Was used. Alternatively, AC4B or AC2B, or AC8A or the like can be used.

When performing the above-mentioned surface treatment, the mating surface with the cylinder block is roughly machined by milling in the preceding step. FIG. 19 shows a rough processing state of this mating surface. Therefore, the intake ports Kc and the exhaust ports Ec shown by the solid lines in FIG. 19 all show the state of the cast holes, and actually, as shown by the broken lines in FIG. After the surface treatment of the part, it is finished by mechanical processing such as drilling, and has a predetermined shape
Intake and exhaust ports with dimensions and surface roughness are obtained.

After the surface treatment, the cylinder head CH is provided with a plurality of tension bolt holes Ht arranged along the longitudinal direction by drilling. These tension bolt holes Ht are for inserting the tension bolts for fastening and fixing when the cylinder head CH after finishing is assembled and fastened and fixed to the cylinder block, and four tension bolts are arranged in the longitudinal direction. It is provided along a pair of parallel straight lines so as to sandwich the cylinder portion. These tension bolt holes Ht are 5 in each row.
It is provided at a location and is set in the vicinity of both ends in the longitudinal direction and between each cylinder portion.

In FIG. 19, all the hole portions shown by the solid line curve are so-called casting holes formed by the casting process. On the other hand, the holes shown by the broken line curves in the figure are not all holes in the cast state, but after performing surface treatment on the intervalve part, etc., they have a predetermined shape and size by mechanical processing such as drilling. Further, it shows a hole formed as a surface roughness.

In the cylinder head CH according to the present embodiment, the inter-valve surface treatment path by the friction stir processing is provided for each cylinder and is relatively short and extends substantially in the width direction of the cylinder head CH. In addition, a long processing path L extending in the longitudinal direction of the cylinder head CH across all cylinders is provided, and is composed of a total of five processing paths. Then, for example, the processing route L, the processing routes R1, R
2, R3, R4 in that order, along these respective processing routes, 4
The surface modification treatment is performed on the intake / exhaust port valve portion of one cylinder in a series of steps.

First, when performing the friction stir processing along all the cylinders along the long processing path L extending in the longitudinal direction of the cylinder head CH, the rotary tool 20 is first positioned at the processing start portion Ls. With the start of the process, the process proceeds along the solid line, from the cylinder on one end side (left end side in FIG. 19) in the longitudinal direction of the cylinder head CH to the cylinder on the opposite end (right end side in FIG. 19). After finishing the surface treatment of the intervalve portion between the intake ports Kc and the intervalve portion of the exhaust port Ec in each cylinder, the rotary tool 20 reaches the end portion Le of the treatment in the pattern of the treatment path L as the end hole treatment. And the rotation of the tool 20 is stopped at this end portion Le and the tool 20 is pulled upward.

The end portion Le of this surface treatment is the tension bolt hole Ht positioned near the end cylinder portion.
It is set so as to coincide with the approximate center of the perforated portion. As described above, this portion is holed by machining after the intervalve surface treatment and removed, so that even if the end hole treatment of the friction stir processing is performed, the end hole does not remain in the final product. .

Further, when performing the friction stir processing of the intervalve portion for each cylinder along the processing paths R1 to R4, the rotary tool 20 is used.
Is first set at the processing start portion Rs in the processing pattern of the processing paths R1 to R4, proceeds along the solid line with the start of processing, and the intake port Kc and the exhaust port Ec in the cylinder are After finishing the surface treatment of the intervalve portion between the two, the rotary tool 20 is moved to the end portion Re of the processing in the pattern of the processing paths R1 to R4 as the end hole treatment, and the end hole Re is used for the end hole. Processing is performed. The end portion Re of this surface treatment is the tension bolt hole H positioned near the cylinder portion.
It is set so as to coincide with the approximate center of the perforated portion of t.

The rotary tool used was of the type II shown in FIG. 5 as described above, and the rotary tool 20 was rotated in the direction opposite to the spiral direction of the spiral groove 25 for processing.
Although not specifically shown, the tool driving means of the rotary tool 20 is more preferably connected to a control panel having a control section mainly composed of, for example, a microcomputer so that signals can be exchanged. Depending on the command signal from the control panel based on a predetermined control program, the processing depth for the surface of the workpiece (member to be processed) and the movement trajectory on the surface of the workpiece are automatically set. It has become so.

In the embodiment of the present invention, when the friction stir processing is performed using the rotary tool 20 (type II) on the cylinder valve interval portion of the cylinder head CH as described above, the valve interval width and the valve interval of the material are In order to perform friction stir processing without causing deformation in the intervalve part under the setting of the required processing width of the part,
Conical taper portion 2 at tool tip 22 of rotary tool 20
A test (test 3) was conducted to find out how to set the tilt angle β (with respect to the central axis Lb of the tool body 21) of No. 4 described above.

In this test 3, as shown in FIG. 7, the inter-valve width Wc of the material and the required processing width Wr of the inter-valve portion are set by changing to the following three cases (case 1 to case 3). Then, a suitable range of the tilt angle β was examined for each case. In FIG. 7, the solid line display between the valves to be processed shows the state of the base metal during the friction stir processing, and the two-dot chain line display shows the finished state by machining after processing (machining allowance ΔM
w) is shown.

In this case, as a related dimension of the rotary tool 20, the diameter dimension Ds of the tip end portion of the tool tip portion 22 is set equal to the required processing width Wr (Ds = Wr), and the tool tip portion 22 is pushed in. The amount was set to a constant value (6.0 mm). Then, the diameter Db of the tool body 21 (that is,
Diameter of upper end of tool tip 22) and conical taper 24
The rotary tools 20 having various inclination angles β with respect to the tool body central axis Lb were manufactured, and the surface modification treatment of the intervalve portion was performed by friction stirring using these rotary tools 20.

The inter-valve width Wc of the material and the required processing width Wr of the inter-valve portion in Cases 1, 2 and 3 are as follows.・ Case 1: Material valve width Wc = 15 mm; required processing width W
r = 7 mm ・ Case 2: Material valve width Wc = 20 mm; required processing width W
r = 7 mm ・ Case 3: Material valve width Wc = 25 mm; required processing width W
The test results for cases 1, 2 and 3 with r = 10 mm or more are shown in Table 2,
3 and 4 respectively.

[0072]

[Table 2]

[0073]

[Table 3]

[0074]

[Table 4]

In Tables 2, 3 and 4 above, in the column of "presence or absence of intervalve portion deformation", x mark is unacceptable, and significant deformation occurs in the intervalve portion due to friction stir processing, and machining (processing This shows a case where the deformation cannot be removed even in the finishing process by the machining allowance ΔMw). Further, the mark Δ indicates that the deformation between the valves is relatively large, and it is delicate whether or not the deformation can be removed in the finishing process by the machining in the subsequent process. Furthermore, the ○ mark is acceptable, and the deformation between the valves is slight,
It shows a case where the deformation can be removed without any trouble in the finishing process by the mechanical processing in the subsequent process.

As is clear from the test results of Tables 2, 3 and 4, in case 1, the inclination angle β of the conical taper portion 24 with respect to the tool body central axis Lb may be set to 15 degrees or less. In case 2, the inclination angle β may be set to 37 degrees or less. Further, in case 3, the tilt angle β may be set to 43 degrees or less.

In Test 3 above, the cylinder head using an Al alloy as a material is used. However, the present invention is effective even when another light metal such as magnesium or its alloy is used as a material. Can be applied to. Further, the cylinder head is not limited to one for a direct injection diesel engine, but may be one used for another type of engine, and is not limited to one for an in-line four-cylinder type or a multi-cylinder type. .

As described above, it is needless to say that the present invention is not limited to the above embodiments, and various improvements and design changes can be made without departing from the scope of the invention.

[0079]

According to the rotary tool for friction stirrer according to the invention of claim 1, the groove portion whose peripheral shape in the vertical cross section including the axis of the tool main body is set to be substantially V-shaped is provided at the tip of the tool. The tapered conical taper portion is provided spirally on the surface, and the groove is set so that the area of the anti-insertion side slope is equal to or larger than the area of the insertion side slope. When the part is pressed into the surface of the member to be processed and enters, the tool tip is rotated in the direction opposite to the screw-in direction of the groove formed in a spiral shape, so that the inside of the groove and the vicinity thereof are friction-stirred. The effect of suppressing the flow of the plastic fluidized bed to the anti-insertion side is further increased, and it is possible to effectively prevent the plastic fluidized bed from rising to the surface side without pressing the friction stir part of the processing target member with the shoulder part. it can. Therefore, it is possible to solve the above-mentioned inconvenience that may occur when using a conventional rotary tool with unnecessary friction stirring by the shoulder portion provided on the lower end side of the tool main body portion, and relatively secure the required processing depth. Friction stirring can be performed in a narrow range. In particular, the tool tip portion has a tapered conical taper portion, and the substantially V-shaped groove portion is spirally provided on the surface of the conical taper portion, so that the processing width at the time of friction stirring is narrower, and Deeper processing depth,
Moreover, it becomes possible to more effectively suppress the swelling of the plastic fluidized bed on the surface side.

Further, according to the friction stirrer rotating tool of the present invention, the groove portion of which the peripheral shape in the vertical cross section including the axis of the tool body is set to be substantially V-shaped is the tip of the tool. The angle between the groove bottom center line passing through the bottom of the groove and the axis orthogonal to the axis of the tool body in the vertical cross section is spirally provided on the surface of the tapered conical taper portion. By setting the angle of the groove portion to be less than the inclination angle with respect to the tool body axis, it is possible to set the area of the non-insertion side inclined surface of the groove portion to be equal to or more than the insertion side inclined surface area. As a result, at the time of friction stir, when the tool tip in the high-speed rotation state is pushed into the surface of the member to be processed and enters, the tool tip is moved in the direction opposite to the screwing direction of the spiral groove. By rotating, the flow suppressing effect on the anti-insertion side of the plastic fluidized layer generated in the groove portion and its vicinity by friction stirring becomes larger, and even if the friction stirring portion of the processing target member is not pressed by the shoulder portion, It is possible to effectively suppress the rise of the plastic fluidized bed on the surface side. Therefore, it is possible to solve the above-mentioned inconvenience that may occur when using a conventional rotary tool with unnecessary friction stirring by the shoulder portion provided on the lower end side of the tool main body portion, and relatively secure the required processing depth. Friction stirring can be performed in a narrow range. In particular, the tool tip portion has a tapered conical taper portion, and the substantially V-shaped groove portion is spirally provided on the surface of the conical taper portion, so that the processing width at the time of friction stirring is narrower, and The processing depth can be made deeper, and moreover, the swelling of the plastic fluidized bed on the surface side can be suppressed more effectively.

Further, according to the invention of claim 3 of the present application, basically, the same effect as that of the invention of claim 2 can be obtained. In particular, in a vertical cross section including the axis of the tool body, the angle formed by the groove bottom center line passing through the bottom of the groove and the axis orthogonal to the tool body axis is set to substantially zero degrees. By doing so, it is possible to substantially maximize the area of the non-insertion side inclined surface of the substantially V-shaped groove portion that is screwed in the same direction, and it is possible to achieve a higher effect.

Further, according to the treatment method of the invention of claim 4, when the light metal members are joined together by the friction stir method, the same effect as that of the invention of any one of claims 1 to 3 can be obtained. Can play.

Further, according to the treatment method of the invention of claim 5, when a predetermined surface portion of the light metal member is subjected to a surface modification treatment by a friction stir method, the treatment method according to any one of claims 1 to 3 is adopted. The same effect as that of the first invention can be obtained.

Furthermore, according to the invention of claim 6 of the present application,
Basically, the same effect as that of the invention of claim 5 can be obtained. In particular, the surface portion between the intake and exhaust ports of the engine cylinder head made of cast aluminum alloy (so-called the valve portion) can be efficiently subjected to a more effective surface modification treatment by the friction stir treatment method. become.

[Brief description of drawings]

FIG. 1 is a front explanatory view of a rotary tool for friction stir (type I) according to a first embodiment of the present invention.

FIG. 2 is a bottom view of the rotary tool.

FIG. 3 is an explanatory front view showing an enlarged tool tip portion of the rotary tool.

FIG. 4 is a cross-sectional explanatory view showing an enlarged part of a threaded groove portion of the tool tip portion.

FIG. 5 is an explanatory front view showing an enlarged tool tip of a rotary tool for friction stir (type II) according to a second embodiment of the invention.

FIG. 6 is a front explanatory view showing a lower end side of a main body portion and a tool tip end portion of a rotary tool according to a comparative example used in Test 1;

FIG. 7 is an explanatory view schematically showing how the rotary tool of type II is pushed into the surface portion of the cylinder head intervalve portion.

FIG. 8 is a cross-sectional explanatory view showing an enlarged cross-sectional state of a surface-treated portion that has been subjected to friction stir processing with a type II rotating tool in Test 1.

FIG. 9 is a cross-sectional explanatory view showing an enlarged cross-sectional state of a surface-treated portion that has been subjected to friction stir processing by a rotating tool of a comparative example in Test 1.

FIG. 10 is a cross-sectional explanatory view showing an enlarged cross-sectional state of a surface-treated portion which has been subjected to friction stir processing at a processing speed of 22.5 mm / min by a rotating tool of type I in Test 2.

FIG. 11 is a cross-sectional explanatory view showing an enlarged cross-sectional state of a surface-treated portion that has been subjected to friction stir processing at a processing speed of 70 mm / min by a type I rotary tool in Test 2;

FIG. 12 is a cross-sectional explanatory view showing an enlarged cross-sectional state of a surface-treated portion subjected to friction stir processing with a type I rotary tool at a processing speed of 150 mm / min in Test 2.

FIG. 13 is a cross-sectional explanatory view showing an enlarged cross-sectional state of a surface-treated portion subjected to friction stir processing at a processing speed of 22.5 mm / min by a type II rotary tool in Test 2;

FIG. 14 is a cross-sectional explanatory view showing an enlarged cross-sectional state of a surface-treated portion subjected to friction stir processing at a processing speed of 70 mm / min by a type II rotary tool in Test 2;

FIG. 15 is a cross-sectional explanatory view showing an enlarged cross-sectional state of a surface-treated portion which has been subjected to friction stir processing at a processing speed of 150 mm / min by a rotating tool of type II in Test 2.

FIG. 16 is an enlarged cross-sectional explanatory view showing a cross-sectional state of a surface-treated portion which has been subjected to friction stir processing at a processing speed of 320 mm / min by a type II rotating tool in Test 2;

FIG. 17 is a cross-sectional explanatory view showing an enlarged cross-sectional state of a surface-treated portion which has been subjected to friction stir processing at a processing speed of 470 mm / min by a type II rotary tool in Test 2;

FIG. 18 is a cross-sectional explanatory view showing an enlarged cross-sectional state of a surface-treated portion which has been subjected to friction stir processing at a processing speed of 750 mm / min by a type II rotating tool in Test 2;

FIG. 19 is an explanatory plan view schematically showing the mating surface of the casting material of the cylinder head according to the embodiment of the present invention with the cylinder block.

FIG. 20 is a perspective view for explaining a friction stir processing method using a rotary tool according to a conventional example.

FIG. 21 is an explanatory view schematically showing a state in which the rotary tool according to the conventional example is pushed into the surface portion of the cylinder head valve portion.

[Explanation of symbols]

10, 20 ... Rotating tools 11, 21 ... Tool main body 12, 22 ... Tool tip portion 14, 24 ... Conical taper portion 15, 25 ... Groove portion 15a ... Groove portion anti-insertion side slope 15b ... Groove portion insertion side slope CH ... Cylinder Head casting member Ec ... Exhaust port (cast hole) Kc ... Intake port (cast hole) Lb ... Tool body axis Lv ... Groove bottom center line Ly ... Axis orthogonal lines α, α1 ... Groove bottom center line axis orthogonal Angles to the line β, β1 ... Inclination angle of the conical taper part with respect to the tool body axis

Claims (6)

[Claims] 1. A tool body having a substantially columnar shape, a tool tip provided coaxially on the tip side of the tool body and having a tapered conical taper portion, and a spiral on the conical taper surface of the tool tip portion. Is provided in the shape of
The peripheral shape in the vertical cross section including the axis of the tool body is approximately V
A groove formed in a letter shape, the groove is set such that the area of the non-insertion side slope is equal to or larger than the area of the insertion side slope, and the tool tip is provided in the spiral shape. A rotary tool for friction stir, which is used by rotating in a direction opposite to the screwing direction of the substantially V-shaped groove. 2. A tool body having a substantially columnar shape, a tool tip provided coaxially on the tip side of the tool body and having a tapered conical taper portion, and a spiral on the conical taper surface of the tool tip portion. Is provided in the shape of
The peripheral shape in the vertical section including the axis of the tool body is approximately V
And a groove portion set in a letter shape, and in the vertical cross section, an angle formed by a groove bottom center line passing through a bottom portion of the groove portion and an axis orthogonal line orthogonal to a tool body portion axis line is the conical taper portion. The angle is set to be less than or equal to the inclination angle with respect to the axis of the tool body, and the tool tip is used by rotating it in the direction opposite to the screw-in direction of the substantially V-shaped groove provided in the spiral shape. Rotating tool for friction stirring. 3. An angle formed by a groove bottom center line passing through the bottom of the groove and an axis orthogonal to the tool body axis is substantially zero in a vertical section including the axis of the tool body. It is set, The rotary tool for friction stirs of Claim 2 characterized by the above-mentioned. 4. When the light metal members are joined together by a friction stir method, the rotating tool according to claim 1 is used to perform a friction stir treatment on the joint portion between the light metal members. Characterized processing method. 5. A predetermined surface portion of the light metal member is subjected to a surface modification treatment by a friction stir method by using the rotary tool according to any one of claims 1 to 3. A treatment method characterized in that the surface portion is subjected to friction stir treatment. 6. The processing method according to claim 5, wherein the light metal member is an engine cylinder head made of an aluminum alloy casting, and the predetermined surface portion is a surface portion between intake and exhaust ports.