JP4617807B2 - Thermal spray pretreatment method - Google Patents

Description

The present invention relates to a thermal spraying preprocessing method for forming the substrate surface before the formation of the thermal spray coating to the roughened surface.

When forming a sprayed coating on the cylinder bore inner surface of a linerless aluminum cylinder block that is effective in reducing the weight of an automobile engine and dealing with exhaust treatment, the cylinder bore inner surface is used as a pre-process to improve the adhesion of the sprayed coating. It is necessary to form on a rough surface. For example, in Patent Document 1 below, blasting is performed as a method for forming a rough surface.
JP-A-11-320414

  However, when performing blasting, the blasting process is performed by moving the blast gun up and down and rotating, so that the blasting material collides with the cylinder head mating surface and the crankshaft bearing surface in the cylinder block. In order to prevent this, a masking material is required, which leads to an increase in size and complexity of the entire apparatus, and an unstable rough surface shape. In addition, the working environment is deteriorated due to dust scattering due to consumption of the blasting material and masking material.

  Therefore, the present invention aims to stabilize the rough surface shape while avoiding the enlargement and complication of the entire apparatus for performing the thermal spray pretreatment and avoiding the deterioration of the working environment.

The present invention is a thermal spraying pretreatment method for forming a base material surface before forming a thermal spray coating on a rough surface using a brush-like tool having a plurality of pin-like members in a main body portion, When the tip of the member is moved while being in contact with the substrate surface, the tool is rotated with respect to the cylindrical inner surface when the substrate surface is formed into a rough surface. The main feature is that the tool is moved in the axial direction and the tool is subjected to axial vibration .

According to the present invention, it is possible to prevent deterioration of the working environment due to dust scattering, such as when performing blasting, and since the masking material is unnecessary, the overall size and complexity of the apparatus can be prevented. The rough surface shape can be stabilized by moving the tip of the member in contact with the substrate surface.
Further, by further applying axial vibration while rotating the tool in the axial direction, the cylindrical inner surface can be made into a finer rough surface, and the adhesion of the sprayed coating to be formed thereafter is further increased. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing a thermal spraying pretreatment method according to a first reference example of the present invention. Here, for example, a cylinder bore inner surface 3 serving as a cylinder inner surface in the cylinder block 1 of the engine is used as the base material surface before forming the sprayed coating. The above-described cylinder block 1 is made of die casting made of an aluminum alloy (ADC12 material), and the cylinder bore inner surface 3 is processed with a certain accuracy. After this cylinder bore inner surface 3 is formed into a rough surface, a thermal spray material made of an iron-based material is sprayed onto the cylinder bore inner surface 3 to form a sprayed coating.

  The cylinder bore inner surface 3 is roughened by using a brush-like tool 5. FIG. 2 is a perspective view of the tool 5, and the tool 5 is provided with a plurality of metal pin-like members 9 harder than the material of the cylinder block 1 on the outer peripheral surface of the cylindrical main body 7. As shown in an enlarged view in FIG. 3, the pin-shaped member 9 has a tip portion having a diameter D of about 1 mm to 8 mm and a plurality of projections 11 provided on the tip portion. The projection 11 has a conical shape with a sharp tip. Is formed. Therefore, the pin-shaped member 9 here has an uneven portion at the tip.

  Note that the lengths of the plurality of protrusions 11 are adjusted so that the tips thereof are all in contact with the cylinder bore inner surface 3.

  Such a tool 5 is attached to a spindle 13 that can be rotationally driven and moved in the axial direction of a processing apparatus main body (not shown).

  Next, the operation will be described. The tool 5 is also rotated integrally with the rotation of the main shaft 13, and in this rotation state, the main shaft 13 is moved downward in FIG. 1 and the tool 5 is inserted into the cylinder bore as shown in FIG. The protrusion 11 at the tip of the member 9 moves while being in contact with the cylinder bore inner surface 3, whereby the cylinder bore inner surface 3 becomes a rough pre-spraying shape 3a as shown in FIG.

  After the tip (lower end) of the tool 5 inserted into the cylinder bore is moved to the lowermost end in FIG. 1 of the cylinder bore inner surface 3, the tool 5 is moved upward while continuing its rotation and pulled out from the cylinder bore. Even when this is pulled out, the cylinder bore inner surface 3 is roughened by the projection 11 at the tip of the pin-shaped member 9.

According to the reference example described above, the cylinder bore inner surface 3 is formed to have a rough surface by using the brush-like tool 5 provided with a plurality of pin-like members 9 in the main body portion 7. Thus, the working environment can be prevented from deteriorating due to dust scattering, and the masking material is unnecessary, so that the entire apparatus can be prevented from becoming large and complicated, thereby contributing to improvement in productivity. Further, by moving the projection 11 at the tip of the pin-shaped member 9 while making contact with the inner surface 3 of the cylinder bore, it is possible to stabilize the rough surface shape as compared with the case where blasting is performed, and then to form a thermal spray to be formed thereafter. The adhesion of the film can be increased.

  Moreover, the cylinder bore inner surface 3 can be roughened in a short time by rotating the tool 5 in the axial direction.

  Further, since the plurality of protrusions 11 are provided at the tip of the pin-shaped member 9, the cylinder bore inner surface 3 can be roughened more finely, and the adhesion of the sprayed coating formed thereafter is further increased.

FIG. 5 is a cross-sectional view corresponding to FIG. 1, showing a second reference example of the present invention. In this reference example , a brush-like tool 50 is divided into a tool base end portion 50a and a tool tip end portion 50b with an electrical insulator 15 interposed at an axially central portion. The tool base end portion 50a and the tool tip end portion 50b include a plurality of tapered pin-like members 21 and 23 around the cylindrical main body portions 17 and 19, respectively.

The tips of the pin-shaped members 21 and 23 are in a state of being separated from the cylinder bore inner surface 3 when the tool 50 is inserted into the cylinder bore with the center of the tool 50 aligned with the center of the cylinder bore.

  In addition, the proximal end voltage terminal 25 is connected to the end of the tool proximal end 50a on the main shaft 13 side, and the distal end side voltage terminal 27 is connected to the distal end of the tool distal end 50b.

  Then, as shown in FIG. 5, with the tool 50 inserted into the cylinder bore, a voltage is applied between the proximal side voltage terminal 25 and the cylinder block 1, and the distal side voltage terminal 27 and the cylinder block 1 In the meantime, a voltage is applied using a voltage applying means (not shown).

  As a result, discharging is performed from the tip of the pin-shaped member 21 at the tool base end portion 50a toward the cylinder bore inner surface 3, and discharge is performed from the tip of the pin-shaped member 23 at the tool distal end portion 50b toward the cylinder bore inner surface 3. By this discharge, the oxide film on the cylinder bore inner surface 3 can be removed and roughened, and the adhesion of the sprayed coating formed thereafter is increased.

Also in this reference example , the work environment can be prevented from deteriorating due to dust scattering, as in blasting, and the masking material is also unnecessary, so the overall size and complexity of the device can be prevented, improving productivity. Can contribute. Further, the rough surface shape is also stabilized as compared with the blast treatment, and the adhesion of the sprayed coating formed thereafter is increased.

In addition, the removal of the oxide film by the above-described discharge can be performed after the cylinder bore inner surface 3 is roughened by the tool 5 of the first reference example , thereby further enhancing the adhesion of the sprayed coating.

Further, in the second reference example described above, compared to the case where the pin-shaped member 9 is rubbed against the cylinder bore inner surface 3 as in the first reference example , there is almost no tool wear and the tool 50 has a longer life. Can do.

  Furthermore, since the above-described tool 50 applies voltage separately to the tool base end part 50a and the tool tip end part 50b on both sides of the electrical insulator 15, the applied voltage can be small. The voltage application means can be reduced in size, and the equipment cost can be kept low.

As the implementation of the invention, the first reference example and similar tools 5 shown in FIG. 1, as shown in FIG. 6, in a state of being inserted into the cylinder bore, it is vibrated in the axial direction indicated by arrow A May be. The vibration frequency at this time shall be 100 Hz-1000 Hz. By further applying axial vibration while rotating the tool 5 in the axial direction, the cylinder bore inner surface 3 can be made to be a finer rough surface, and the adhesion of the sprayed coating formed thereafter is further increased. .

The above-mentioned base material surface is not limited to the cylinder bore inner surface 3 in the engine cylinder block, and the present invention can be applied to other cylindrical inner surfaces .

  Moreover, about the rough surface shape of the cylinder bore inner surface 3 processed by thermal spraying pretreatment as described above, the shape is measured by a contact-type shape measuring machine such as a laser and the accuracy is guaranteed.

  FIG. 7 is an overall configuration diagram showing an outline of a thermal spraying apparatus for forming a thermal spray coating after roughening the cylinder bore inner surface 3. In this thermal spraying apparatus, a gas spray type spray gun 31 is inserted into the center of the cylinder bore, and an iron-based metal material melted as a thermal spraying material is sprayed from the thermal spray port 31a as a spray 33 to spray onto the inner surface 3 of the cylinder bore. A film 32 is formed.

  The thermal spray gun 31 is supplied with a molten metal 37 of an iron-based metal material as a thermal spray material from a thermal feeder 35, and also has a fuel gas cylinder 39 storing fuel such as acetylene, propane or ethylene, and an oxygen cylinder storing oxygen. The fuel gas and oxygen are supplied from the pipe 41 through the pipes 43 and 45, respectively.

  The above-mentioned molten wire 37 is fed to the thermal spray gun 31 downward from the upper end of the molten wire feed hole 47 penetrating vertically in the central portion. Further, the fuel and oxygen are supplied to the gas guide channel 51 formed in the cylindrical portion 49 outside the melt feed hole 47 so as to penetrate in the vertical direction. The supplied mixed gas of fuel and oxygen flows out from the lower end opening 51a in FIG. 7 of the gas guide channel 51 and is ignited to form a combustion flame 53.

  An atomizing air flow channel 55 is provided on the outer peripheral side of the cylindrical portion 49, and an accelerator air flow channel 61 formed between the cylindrical partition wall 57 and the outer wall 59 is provided on the outer peripheral side thereof. It is.

  The atomizing air flowing through the atomizing air flow channel 55 sends the heat of the combustion flame 53 forward (downward in FIG. 7) to cool the peripheral portion, and sends the molten wire 37 forward. On the other hand, the accelerator air flowing through the accelerator air flow path 61 sends the molten wire 37 fed forward and melted as the droplet 33 toward the cylinder bore inner surface 3 so as to intersect the feed direction, and sprayed onto the cylinder bore inner surface 3. A film 32 is formed.

  Atomized air is supplied to the atomized air flow channel 55 from an atomized air supply source 67 through an air supply pipe 71 provided with a pressure reducing valve 69. On the other hand, accelerator air is supplied from the accelerator air supply source 73 to the accelerator air flow channel 61 through an air supply pipe 79 provided with a pressure reducing valve 75 and a micro mist filter 77.

  The partition wall 57 between the atomizing air flow channel 55 and the accelerator air flow channel 61 is provided with a rotating cylinder portion 83 that can rotate with respect to the outer wall 59 via a bearing 81 at the lower end portion in FIG. Yes. A rotating blade 85 located in the accelerator air flow path 61 is provided on the outer periphery of the upper portion of the rotating cylinder portion 83. When the accelerator air flowing through the accelerator air flow path 61 acts on the rotary blade 85, the rotary cylinder portion 83 rotates.

  A tip member 87 that rotates integrally with the rotary cylinder 83 is fixed to the tip (lower end) surface 83 a of the rotary cylinder 83. A protrusion 91 having an ejection flow path 89 communicating with the accelerator air flow path 61 through the bearing 81 is provided at a part of the peripheral edge of the distal end member 87, and the droplet 33 is formed at the distal end of the ejection flow path 89. The above-described thermal spraying port 31a is provided for jetting.

  The tip member 87 including the spray port 31a rotates integrally with the rotary cylinder portion 83 while moving the spray gun 31 in the axial direction of the cylinder bore, so that the spray coating 32 is formed on almost the entire area of the cylinder bore inner surface 3.

It is sectional drawing which shows the thermal spraying pretreatment method concerning the 1st reference example of this invention. It is a perspective view of the tool in the 1st reference example . It is a perspective view which shows the front-end | tip shape of the tool shown in FIG. It is sectional drawing of the cylinder block which shows the state which roughened the cylinder bore inner surface by the 1st reference example . It is sectional drawing equivalent to the said FIG. 1 which shows the 2nd reference example of this invention. It shows the implementation form of the present invention, is a cross-sectional view corresponding to FIG 1. It is a whole block diagram which shows the outline of a thermal spraying apparatus.

Explanation of symbols

1 Cylinder block 3 Cylinder bore inner surface (base material surface, cylindrical inner surface)
5,50 Brush-shaped tool 7,17,19 Main body 9,21,23 Pin-shaped member 32 Thermal spray coating

Claims (4)

  A thermal spraying pretreatment method for forming a surface of a base material before forming a thermal spray coating on a rough surface using a brush-like tool having a plurality of pin-like members on a main body, wherein the tip of the pin-like member is When the substrate surface is formed into a rough surface by being moved while being in contact with the substrate surface, the substrate surface is defined as a cylindrical inner surface, and the tool is rotated in the axial direction with respect to the cylindrical inner surface. A thermal spraying pretreatment method characterized by moving the tool and applying an axial vibration to the tool.   The thermal spraying pretreatment method according to claim 1, wherein the pin-shaped member has an uneven portion at a tip.   The thermal spraying pretreatment method according to claim 1, wherein the main body of the tool has a cylindrical shape, and a plurality of the pin-like members are provided on an outer peripheral surface of the cylindrical portion.   The thermal spraying pretreatment method according to any one of claims 1 to 3, wherein discharge is performed from the tip of the pin-shaped member toward the surface of the base material.

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