JP5794017B2 - Thermal spray coating forming method and thermal spray coating forming apparatus - Google Patents

Description

  The present invention relates to a thermal spray coating forming method and a thermal spray coating forming apparatus for forming a thermal spray coating by supplying molten metal obtained by melting a thermal spray material to a sprayed material.

  Conventionally, a coating is formed by spraying a metal or ceramic material on the inner surface of a cylinder bore of a cylinder block for an internal combustion engine such as an automobile, and then honing is applied to the sprayed coating so that the surface roughness is appropriate. A thermal spray coating forming method for forming a moving surface is known. As a thermal spray coating forming method, there is a wire plasma method using a wire material as a material and plasma as a heat source (see, for example, Patent Document 1 below).

  In the wire plasma method, a pilot arc is generated by applying a high frequency and a high voltage between a nozzle for discharging plasma gas and a cathode disposed in the nozzle, with the nozzle side serving as an anode. The generated pilot arc rides on a plasma gas flow flowing in the nozzle and moves to a wire that is an anode similar to the nozzle to form a plasma arc. The wire is melted by the heat of the plasma arc, and the molten metal of the melted wire is sprayed onto the object to be sprayed by the plasma gas flow.

US Pat. No. 5,938,944

  By the way, in the above-described wire plasma method, it is difficult to stabilize the molten state of the sequentially fed wires, and in some cases, coarse droplets (particles) are rarely generated in the molten metal and sprayed onto the object to be sprayed. In this case, coarse particles may be included in the sprayed coating, and may appear as protrusions on the surface of the sprayed coating.

  And if honing is carried out with this protruding part appearing, the honing grindstone will collide with the protruding part from the side, so that the protruding part is not ground and falls off with the surrounding sprayed coating, resulting in a defective product. It may become.

  Therefore, an object of the present invention is to suppress the dropout of the protrusions formed on the surface of the sprayed coating in the honing process after the spraying process.

The present invention provides a fusion formed between the thermal spraying process of forming a thermal spray coating on the sprayed material and the honing process of performing honing on the surface of the thermal spray coating so as to protrude from the surface of the thermal spray coating in the thermal spraying process. A protrusion removing step is provided for removing the metal-containing protrusion without causing the surrounding thermal spray coating to drop off. In the protrusion removing step, a flexible protrusion removing tool is slid against the protrusion. It is characterized by removing .

  According to the present invention, since the protrusion formed on the surface of the sprayed coating is removed in the protrusion removing step after the spraying process, the protrusion formed on the surface of the sprayed coating in the subsequent honing process. Dropping can be suppressed.

It is operation | movement explanatory drawing which shows the state which has removed the projection part which generate | occur | produced in the thermal spray coating of the to-be-sprayed object with the projection part removal tool concerning the 1st Embodiment of this invention. It is an operation | work process figure which shows the thermal spray coating formation method of this invention. It is effect | action explanatory drawing which shows the state which has removed the projection part which generate | occur | produced in the thermal spray coating of the to-be-sprayed object with the projection part removal tool concerning the 2nd Embodiment of this invention. It is effect | action explanatory drawing which shows the state which has removed the projection part which generate | occur | produced in the thermal spray coating of the to-be-sprayed object with the projection part removal tool concerning the 3rd Embodiment of this invention. It is effect | action explanatory drawing which shows the state which has removed the projection part which generate | occur | produced in the thermal spray coating of the to-be-sprayed object with the projection part removal tool concerning the 4th Embodiment of this invention. It is action | operation description which shows the state which has removed the projection part which generate | occur | produced in the thermal spray coating of the to-be-sprayed object with the projection part removal tool concerning the 5th Embodiment of this invention. (A) is a perspective view which shows the operation | movement which inserts the spray gun of the plasma spraying apparatus which forms the sprayed coating of a to-be-sprayed object in a cylinder bore, (b) is generated at the nozzle tip of the spray gun of (a). It is sectional drawing which shows the state which melt | dissolved a wire with the plasma arc and formed the thermal spray coating. (A) is sectional drawing which shows the state in which the coarse particle which generate | occur | produced in the droplet was sprayed on the cylinder bore inner surface, (b) is a projection part on the surface of the sprayed coating of the coarse particle of (a). Sectional drawing which shows the state which appeared, (c) is sectional drawing which shows the state which is performing the honing process in the state where the projection part of (b) appeared, (d) is protrusion by the honing process of (c) It is sectional drawing which shows the state from which the part fell off with the surrounding thermal spray coating. (A) is a perspective view showing an operation of inserting a honing head for honing the surface of the thermal spray coating into the cylinder bore, and (b) is honing the surface of the thermal spray coating by the honing head of (a). It is sectional drawing which shows a state.

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

  FIG. 1 shows a state in which the protruding portion 7 generated on the sprayed coating 5 on the surface of the sprayed object 3 is removed by the protruding portion removing tool 1 as the protruding portion removing means according to the first embodiment of the present invention. Show. Here, the sprayed object 3 is a cylinder block for an internal combustion engine such as an automobile, and the above-mentioned sprayed coating 5 is formed on the sprayed surface 3a of the inner surface of the cylinder bore. For the formation of the sprayed coating 5, a plasma spraying apparatus shown in FIG. 7 is used.

  The plasma spraying apparatus sprays a molten metal droplet 11 obtained by melting a wire 9 from the tip of a spray gun 8 as a spraying means that can rotate and move in the axial direction of a cylinder bore, and sprays the sprayed surface 3a. The spray gun 7 has a nozzle 13 at the tip, generates a plasma arc between an electrode (cathode) 15 and a wire (anode) 9 in the nozzle 13, and the wire 9 that is sequentially sent by the thermal energy of the plasma arc. Melt the tip.

  At that time, in the nozzle 13, the plasma gas is discharged from the plasma gas discharge passage 17 at the center, and at the same time, the atomizing air is discharged from the surrounding atomizing air discharge passage 19. The droplet 11 described above is caused to flow by the plasma gas flow and the atomizing air flow, and is sprayed onto the sprayed surface 3a to form the sprayed coating 5.

  When the sprayed coating 5 is formed in this way, as described above, when the molten state of the wire 9 becomes unstable, as shown in FIG. The particles 21 that are lumps are sprayed on the sprayed surface 3a. In this case, the above-described coarse particles 21 are included in the thermal spray coating 5 and appear on the surface of the thermal spray coating 5 as protrusions 7 made of molten metal as shown in FIG. 8B. become.

  The protrusions 7 are formed on the surface of the sprayed surface 5a during the formation of the sprayed coating 5, or foreign matter mixed in the coating during the spraying process (chips brought in from the previous process, Also includes protrusions generated in the coating layer with spatter as the core.

  Then, when the honing process is performed using the honing tool 23 as the honing means as shown in FIG. 8C with the protrusion 7 appearing, the grindstone 25 attached to the outer peripheral portion of the rotating honing head 24 protrudes. Colliding from the side of the part 7. When the grindstone 25 collides from the side of the projecting portion 7, the projecting portion 7 falls off together with the surrounding sprayed coating 5 without being ground as shown in FIG. 8D, and a recess 28 is formed on the inner surface of the bore. . The recess 28 causes problems such as oil entering during operation of the internal combustion engine and increasing oil consumption.

  Therefore, in the present embodiment, such a protruding portion 7 is removed in advance using the protruding portion removing tool 1 shown in FIG. 1 before performing the honing process.

  That is, in the thermal spray coating forming method using the thermal spray coating forming apparatus according to the present embodiment, as shown in FIG. 2, after the thermal spraying step 27, a projection removing step 29 using the projection removing tool 1 is set, and the projection The honing process 31 is set after the part removal process 29. In the protrusion removal step 29, the protrusion 7 containing the molten metal is removed without accompanying the drop of the sprayed coating around the protrusion 7. In the honing step 31, as shown in FIG. 9, the honing head 24 having the grindstone 25 on the outer peripheral portion is moved in the axial direction while rotating, and the surface of the sprayed coating 5 formed on the sprayed surface 3a is ground. Finish processing.

  The protrusion removing tool 1 shown in FIG. 1 has a plurality of rectangular flaps 39 as flexible sheet-like members attached around the entire outer periphery of a rotating shaft 37 that is rotated by a drive mechanism 35. A large number of abrasive grains 41 serving as a grinding portion are attached to the front surface.

  The abrasive grains 41 are made of, for example, alumina, silicon, zirconia (granularity # 40 to # 600), and are attached to one surface of the flap 39 mainly on the front end side. The flaps 39 may be, for example, reinforced paper used for a portion that becomes a base paper of a paper file, and are attached at almost equal intervals along the circumferential direction of the rotation shaft 37.

  When such a protrusion removing tool 1 is inserted into the cylinder bore after the thermal spray coating is formed and the rotary shaft 37 is rotated by driving the drive mechanism 35, the plurality of flaps 39 are also rotated simultaneously. The flap 39 at the time of this rotation makes the side on which the abrasive grains 41 are attached the front side in the rotation direction.

  Since the flap 39 is flexible and flexible, it is deformed so that the front side in the rotational direction becomes a convex curved surface during rotation. By making a part of the front end side of the deformed state of the flap 39 in contact with at least the projecting portion 7 of the thermal spray coating 5, the abrasive grains 41 slide with respect to the projecting portion 7, whereby the projecting portion 7 can be gradually ground and removed from the tip side. In this case, since the protrusion 7 is gradually ground by the abrasive grains 41, it is possible to suppress the dropout accompanying the thermal spray coating 5 around the protrusion 7.

  In the actual protrusion removal operation, the protrusion removal tool 1 is inserted into the cylinder bore while the center of the rotation shaft 37 is aligned with the center axis of the cylinder bore, and is gradually moved in the axial direction while rotating. At that time, the rotational speed of the rotary shaft 37 is set to 500 to 10000 rpm, and the machining allowance H (cutting amount) is set to 0.2 mm to 2.0 mm as shown in FIG. For example, when the diameter of the coarse particles 21 forming the protrusion 7 is 1.0 mm, the protrusion amount of the protrusion 7 is about 0.5 mm, which is half the diameter (the other half is in the thermal spray coating 5. By setting the removal allowance H to 0.5 mm, almost the entire protrusion 7 can be removed. In this case, since the projection 7 is formed by almost half of the coarse particles 21, the remaining half remains buried in the sprayed coating 5 after the projection removal operation.

  By removing the protrusion 7 in this manner and then performing honing, falling off with the sprayed coating 5 around the protrusion 7 can be suppressed, and finishing of the surface of the sprayed coating 5 is performed with high accuracy. Generation of defective products can be suppressed.

  Further, in this embodiment, since the flexible flap 39 is used, even if the cylinder bore inner diameter is shifted by about ± 0.1 mm due to a manufacturing error, for example, by setting the machining allowance H to about 1.0 mm, There is no problem in removing the protrusion 7. That is, the length from the center of the rotating shaft 37 to the tip of the flap 39 can be reliably removed without matching the cylinder bore inner diameter with high accuracy.

  Further, the processing speed is faster than that using a brush described later, and the workability is excellent.

  FIG. 3 shows a state in which the protruding portion 7 generated on the sprayed coating 5 of the sprayed object 3 is removed by the protruding portion removing tool 1A according to the second embodiment of the present invention. In this embodiment, a brush 43 is used instead of the flap 39 provided with the abrasive grains 41 used in the first embodiment of FIG.

  The brush 43 is formed by attaching a large number of flexible wires 45 made of a ferrous metal around the rotary shaft 37. The wire 45 has a hardness of, for example, HRC 40 or more and a wire diameter (diameter) of 0.150 mm to 0.500 mm.

  Alternatively, the wire 45 may be made by attaching alumina abrasive grains (grain size # 40 to # 600) to the surface of a flexible and flexible resin wire.

  The protrusion removal tool 1A using the brush 43 is also inserted into the cylinder bore with the center of the rotation shaft 37 aligned with the center axis of the cylinder bore, as with the protrusion removal tool 1 using the flap 39 described above. Gradually moving in the axial direction. At that time, the rotational speed of the rotating shaft 37 is set to 500 to 10000 rpm, and the machining allowance H (cutting amount) is set to 0.2 mm to 2.0 mm, similarly to the protrusion removal tool 1.

  By rotating the brush 43, the tip of the wire 45 comes into contact with and slides on the protruding portion 7, and the protruding portion 7 is removed.

  Also in the above-described second embodiment, honing is performed after removing the protrusion 7, so that falling off with the sprayed coating 5 around the protrusion 7 can be suppressed, and the surface of the sprayed coating 5 is finished. Processing can be performed with high accuracy, and the occurrence of defective products can be suppressed.

  Similarly to the first embodiment, for example, when the machining allowance H is set to about 1.0 mm, even if the cylinder bore inner diameter is shifted by about ± 0.1 mm due to a manufacturing error, there is a problem in removing the protruding portion 7. Absent. That is, the length from the center of the rotating shaft 37 to the tip of the wire 45 can be reliably removed without matching the cylinder bore inner diameter with high accuracy. Furthermore, in the second embodiment, the tool life can be extended as compared with the first embodiment using the flap 39.

  In the first and second embodiments described above, the protrusion removal tool 1 or 1A is rotated with respect to the sprayed object 3 in the fixed state, but the protrusion removal tool 1 or 1A in the fixed state is rotated. The sprayed object 3 may be rotated.

  FIG. 4 shows a state in which the protruding portion 7 generated on the sprayed coating 5 on the surface of the sprayed object 3 is removed by the protruding portion removing tool 1B according to the third embodiment of the present invention. In this embodiment, a cylindrical grindstone (which may be a rubber grindstone) 47 is attached around the tip of the rotating shaft 37, and the protrusion 7 is ground by contouring.

  That is, the outer diameter of the grindstone 47 is set to be smaller than the inner diameter of the cylinder bore after the thermal spray coating 5 is formed. The part 7 is ground and removed.

  Therefore, also in the present embodiment, by performing the honing process after removing the protrusion 7 by the contouring process, it is possible to suppress the dropout accompanying the sprayed coating 5 around the protrusion 7, and the surface of the sprayed coating 5 can be suppressed. It is possible to suppress the occurrence of defective products by finishing with high accuracy.

  Further, in the present embodiment, the machining accuracy can be increased by performing the contouring process using the grindstone 47 as compared with the above-described embodiments.

  In addition, the rotation speed of the grindstone 47 in this embodiment is 2000 rpm to 10000 rpm, and the machining allowance is 0.1 mm to 0.5 mm.

  FIG. 5 shows a state in which the protrusion 7 generated on the thermal spray coating 5 of the sprayed object 3 is removed by the protrusion removal tool 1C according to the fourth embodiment of the present invention. In this embodiment, a laser beam supply unit is configured as the protrusion removal tool 1C. The laser beam supply means irradiates a laser beam 49 having thermal energy supplied from a laser oscillator (not shown) from the laser irradiation head 51 toward the projection 7, and melts and removes the projection 7.

  FIG. 6 shows a state where the protrusion 7 generated on the thermal spray coating 5 of the sprayed object 3 is removed by the protrusion removal tool 1D according to the fifth embodiment of the present invention. In this embodiment, a plasma generating means for generating the plasma arc 53 shown in FIG. 7 is configured as the protrusion removal tool 1D. The plasma generating means removes the projection 7 by applying thermal energy to the projection 7 by a plasma arc formed between the electrode provided on the nozzle 55 and the sprayed material 3.

  Therefore, also in each of the fourth and fifth embodiments, by performing the honing process after removing the protruding portion 7 by melting, it is possible to suppress the dropout with the sprayed coating 5 around the protruding portion 7, and the thermal spraying. The finishing of the surface of the film 5 can be performed with high accuracy to suppress the occurrence of defective products.

  Although the laser beam is used in the fourth embodiment and the plasma arc is used in the fifth embodiment, the thermal energy that can melt the projection 7 is limited to these. Absent.

1,1A, 1B, 1C, 1D Protrusion removal tool (protrusion removal means)
3 Sprayed object 3a Sprayed surface of sprayed object 5 Sprayed coating 7 Projection 8 Spraying gun (spraying means)
9 Wire (material for thermal spraying)
11 Liquid droplets (molten metal)
21 Coarse particles of droplet 23 Honing tool (honing means)
27 Thermal spraying process 29 Projection removal process 31 Honing process 39 Flap (flexible sheet-like member)
41 Abrasive grains 43 Brush 45 Wire 47 Grinding stone 49 Laser beam 53 Plasma arc

Claims (9)

A thermal spraying process for forming a thermal spray coating by supplying a molten metal obtained by melting a thermal spray material to a sprayed material, and forming the thermal spray coating in this thermal spraying process so as to protrude from the surface of the thermal spray coating. And a protrusion removing step for removing the protrusion including the molten metal without dropping off the surrounding sprayed coating, and with the protrusion removed in the protrusion removing step, the surface of the sprayed coating is removed. and honing step of performing the honing process, the possess Te,
The method for forming a sprayed coating is characterized in that the protrusion removal step includes removing a flexible protrusion removal tool by sliding the protrusion against the protrusion . The thermal spraying according to claim 1 , wherein the protrusion removing tool is provided with abrasive grains on a flexible sheet-like member, and the abrasive grains are slid against the protrusions to be ground and removed. Film formation method. The thermal spray coating formation according to claim 1, wherein the protrusion removal tool is a brush having a plurality of flexible wires, and the tip of the brush is slid with respect to the protrusion. Way . The thermal spray coating forming method according to claim 2 , wherein the protrusion removal tool is slid relative to the protrusion by rotating relative to the sprayed object. A thermal spraying process for forming a thermal spray coating by supplying a molten metal obtained by melting a thermal spray material to a sprayed material, and forming the thermal spray coating in this thermal spraying process so as to protrude from the surface of the thermal spray coating. And a protrusion removing step for removing the protrusion including the molten metal without dropping off the surrounding sprayed coating, and with the protrusion removed in the protrusion removing step, the surface of the sprayed coating is removed. A honing process for performing honing processing,
In the protrusion removing step, the protrusion removing tool provided with the grindstone is moved relative to the surface of the thermal spray coating while rotating, so that the grindstone is slid with respect to the protrusion to be ground and removed. A method for forming a sprayed coating, comprising: A thermal spraying process for forming a thermal spray coating by supplying a molten metal obtained by melting a thermal spray material to a sprayed material, and forming the thermal spray coating in this thermal spraying process so as to protrude from the surface of the thermal spray coating. And a protrusion removing step for removing the protrusion including the molten metal without dropping off the surrounding sprayed coating, and with the protrusion removed in the protrusion removing step, the surface of the sprayed coating is removed. A honing process for performing honing processing,
The method for forming a sprayed coating is characterized in that, in the protrusion removal step, the protrusion is removed by applying thermal energy to the protrusion to melt the protrusion. A thermal spraying means for forming a thermal spray coating by supplying a molten metal obtained by melting a thermal spraying material to an object to be sprayed and formed so as to protrude from the surface of the thermal spray coating when the thermal spray coating is formed by the thermal spraying means. And a protrusion removing means for removing the protrusion including the molten metal without dropping off the surrounding sprayed coating, and the protrusion removed by the protrusion removing means with respect to the surface of the sprayed coating. and honing means for performing the honing process, the possess Te,
The said protrusion part removal means slides a flexible protrusion part removal tool with respect to the said protrusion part, and removes it, The thermal spray coating formation apparatus characterized by the above-mentioned .   A thermal spraying means for forming a thermal spray coating by supplying a molten metal obtained by melting a thermal spraying material to an object to be sprayed and formed so as to protrude from the surface of the thermal spray coating when the thermal spray coating is formed by the thermal spraying means. And a protrusion removing means for removing the protrusion including the molten metal without dropping off the surrounding sprayed coating, and the protrusion removed by the protrusion removing means with respect to the surface of the sprayed coating. Honing means for performing honing processing,
  The protrusion removing means slides the grindstone against the protrusion to grind and remove it by rotating a protrusion removing tool provided with a grindstone along the surface of the thermal spray coating while rotating. An apparatus for forming a sprayed coating, characterized in that:   A thermal spraying means for forming a thermal spray coating by supplying a molten metal obtained by melting a thermal spraying material to an object to be sprayed and formed so as to protrude from the surface of the thermal spray coating when the thermal spray coating is formed by the thermal spraying means. And a protrusion removing means for removing the protrusion including the molten metal without dropping off the surrounding sprayed coating, and the protrusion removed by the protrusion removing means with respect to the surface of the sprayed coating. Honing means for performing honing processing,
  The said protrusion part removal means removes the said protrusion part by giving a thermal energy to the said protrusion part and making it melt | dissolve, The thermal spray coating formation apparatus characterized by the above-mentioned.

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