JP5092539B2 - Anodizing equipment - Google Patents

Description

    The present invention relates to an anodizing apparatus for metal parts.

    In general, anodic oxidation is performed by using an acidic electrolytic solution containing sulfuric acid, chromic acid or the like to bring the object to be treated to the positive electrode side and energizing, for example, to oxidize the surface of the aluminum-based metal object to be treated. It is the processing method which forms thickness. However, when the alumite film thickness increases, electricity becomes difficult to flow due to its film characteristics (insulating properties), and the oxidation effect decreases. Therefore, it takes a long time to achieve the required film thickness, and the production efficiency is poor.

Therefore, by improving the current density and anodizing with a large current, the processing time can be shortened and an alumite film having a predetermined thickness can be obtained efficiently.
JP 2006-336050 A JP 2007-002316 A

The description in Patent Document 1 discloses a processing apparatus capable of forming a metal oxide film uniformly and at high speed on a metal product. The second electrode part is formed by processing a discharge hole (hole) in a ring-shaped metal material. Since the second electrode and the discharge hole are integrated, the size can be reduced. However, when the current density is increased and processed, the metal ions Cu ^{2+ and the} like are deposited quickly, and the discharge holes are likely to be clogged.

  The description of Patent Document 2 discloses an anodizing apparatus that has an injection type nozzle and efficiently forms a metal oxide film partially on the surface of a metal part. The nozzle portion is made of a non-conductive material to prevent an electrical short circuit, but is separate from the second electrode. Therefore, it cannot be downsized.

  An object of the present invention is to reduce clogging of discharge holes and to shorten the formation time of a metal oxide film.

In the first aspect of the present invention, a first electrode portion for passing a current to a metal workpiece,
A second electrode portion having a discharge hole portion having a discharge hole opposed to the object to be processed; an electrolyte supply means for supplying an electrolytic solution from the discharge hole portion toward the object to be processed; and the first electrode And an energizing means for applying a voltage to the second electrode part, wherein the body of the second electrode part is formed of a metal member, the discharge hole part is formed of a synthetic resin, and the discharge The hole is embedded in the metal member.

  In a second aspect of the present invention, the discharge hole portion is prevented from being detached from the second electrode portion.

  In a third aspect of the present invention, the discharge hole has a passage through which the electrolyte flows from the electrolyte supply means to the discharge hole, and the discharge hole on the side where the electrolyte flows into the discharge hole The outer peripheral length of the part is larger than the outer peripheral length on the opposite side.

  In a fourth aspect of the present invention, the discharge hole portion is disposed so as not to rotate with respect to the second electrode portion.

  In a fifth aspect of the present invention, at least a part of the side peripheral surface of the discharge hole portion is chamfered.

  In a sixth aspect of the present invention, the discharge section is made of an acid resistant resin.

  According to the first aspect of the present invention, in the anodizing treatment, the clogging of the discharge holes due to metal deposition can be reduced, and the treatment time of the anodizing treatment can be shortened.

  According to the second aspect of the present invention, it is possible to prevent the discharge hole portion from coming off from the second electrode portion.

  According to the third aspect of the present invention, it is possible to prevent the discharge hole portion from coming off from the second electrode portion when the electrolytic solution is fed.

  According to invention of Claim 4, rotation with respect to the 2nd electrode part of a discharge hole part can be prevented.

  According to the invention described in claim 5, it is possible to prevent the discharge hole portion from rotating with respect to the second electrode portion with a simple configuration.

  Furthermore, according to the invention described in claim 6, since the resin is excellent in acid resistance, it is hardly affected by the electrolytic solution and is not easily deteriorated.

  The anodizing apparatus of the present invention includes a first electrode part, a second electrode part, an electrolytic solution supply means, and an energization means.

  A 1st electrode part is comprised with the conductor which contacts a to-be-processed object. Since the conductive material requires electrical conductivity, a metal material with good electrical conductivity is preferable.

  Examples of the object to be processed include metal parts. You may have a recessed part in a side peripheral surface. Specifically, an aluminum base metal piston can be exemplified, but the present invention is not limited thereto. It is preferable to use a cylindrical or rod-like ring groove having a ring groove that goes around the outer circumference on its outer surface. Here, the aluminum-based metal includes an aluminum metal and an alloy obtained by mixing other elements such as copper, zinc, and silicon with aluminum.

  Further, the first electrode part can be incorporated in a holding means for holding the object to be processed. The holding means can have a rotation driving unit as a rotating means for rotating the workpiece to be held. The rotation driving unit may be configured such that the object to be processed rotates around the axis of the object to be processed. Further, the holding means may have a moving means for moving the object to be processed to, for example, an attachment / detachment position and an electrolytic treatment position.

The second electrode portion includes an electrolyte passage, has an inner peripheral surface surrounding a side peripheral surface of the object to be processed, and communicates with the electrolyte passage on the inner peripheral surface and discharge holes facing the concave portion of the object to be processed. It is an electrode which has inside. The main body of the second electrode portion is formed of a conductive metal member, the discharge hole portion is formed of synthetic resin, and the discharge hole portion is embedded in the second electrode. Specifically, the main body is SUS304, SUS316, SUS316L, Ti, TiO, TiO ₂ , Pt, etc., and the discharge holes are high-density polyethylene, polypropylene, polyphenylene sulfide, fluororesin, phenol resin, epoxy resin with excellent acid resistance. It can be illustrated. In order to suppress the molding shrinkage, a filler may be contained.

  The shape of the inner peripheral surface and the shape of the discharge hole can have different shapes according to the surface to be processed of the object to be processed. The shape of the discharge hole matched to the surface to be processed having a recess is generally circular, but in some cases, an elliptical shape or a rectangular shape is also preferable. Further, the discharge holes may be arranged inside the second electrode portion so as to be separated from each other in the extending direction of one or a plurality of rings. The number of discharge holes of the second electrode part, the size of the discharge holes, and the like can be freely set according to the object to be processed.

  When an aluminum alloy piston is used as the workpiece, the discharge hole diameter is preferably 0.5 to 2.0 mm and the number of discharge holes is preferably 4 to 32.

  The electrolytic solution supply means includes a storage tank that stores the electrolytic solution, an inflow path that connects the storage tank and the electrolytic solution passage, and a pump that is disposed in the inflow path and sends the electrolytic solution from the storage tank to the electrolytic solution passage. Can be configured.

  The electrolyte supply means may be provided with a cooling means for cooling the electrolyte, a temperature control means for controlling the temperature of the electrolyte, and a flow rate control means for controlling the flow rate of the electrolyte.

  Moreover, it is preferable that the 2nd electrode part is comprised combining the storage tank which collects electrolyte solution. The storage tank collects the electrolytic solution after being supplied to the object to be processed, and sends it to the supply means. The storage tank main body may be a container with an open top or a sealed container depending on the object to be processed. One or a plurality of storage tanks can be installed in communication. Since the electrolytic solution often uses a strong acid, the material of the storage tank body is preferably made of SUS316 or vinyl chloride. The storage tank may be formed integrally with the second electrode portion or may be detachable.

  The energization means is means for applying a voltage between the first electrode portion and the second electrode portion. This energization means preferably has current control means so that the current density can be adjusted. The current control means includes an ammeter, a voltmeter, a rectifier and the like, and a conventionally known one can be used.

(Example)
Hereinafter, based on an Example, the anodizing apparatus of this invention is demonstrated in detail. A functional explanatory diagram of the anodizing apparatus of this embodiment is shown in FIG. This anodizing apparatus is for anodizing a piston ring groove W1 of a piston W made of aluminum alloy. More precisely, of the three piston ring grooves W1, W2 and W3 formed from the top to the skirt on the outer peripheral surface of the top of the piston W, the top outer peripheral surface including the piston ring groove W1 on the top side is mainly used as the anode. It is an oxidation treatment.

  This anodizing apparatus has a holding means 1 for holding a piston W, an electrolytic cell 3 having an electrode portion 2 constituting a ring-shaped electrode, an electrolyte supply means 4, and an energizing means 5.

  The holding means 1 includes a reduction motor 11 fixed to an elevating part of an elevating device (not shown) fixed to an upper end of a frame (not shown), and a holding shaft 12 fixed to an output shaft of the reduction motor 11. Become. A detachable locking claw (not shown) is provided on the inner peripheral surface of the piston W at the lower end of the holding shaft 12. The locking claw is inserted in the axial direction so as to cover the inner cavity of the piston W from the lower end side, and the holding shaft 12 and the piston W are coaxial. In addition, a current collecting ring 51 constituting the energizing means 5 described later is fixed in the middle of the holding shaft 12 in the axial direction, and the current collecting ring 51 and an engaging claw (not shown) are electrically connected. And it is electrically connected to the piston W through the locking claw. The current collecting ring 51 and the holding shaft 12 constitute the first electrode portion of the present invention.

  A cylindrical rubber masking W5 is mounted and fixed on the outer peripheral surface of the ridge forming the boundary between the piston ring groove W2 and the piston ring groove W3 excluding the top of the piston W, and the lower part excluding the top of the piston W is Covered so that the electrolyte does not touch. The current collecting ring 51, the holding shaft 12, and the piston W constitute an anode.

  The second electrode portion 2 is a ring-shaped electrode formed of a rectangular substrate 21, a disk-shaped intermediate plate 22 and a metal member, as shown in FIGS. It is comprised from the main body 23, the conductor part 24, and the discharge hole part 25 which consists of synthetic resins. Since the discharge hole portion 25 is made of an acid-resistant synthetic resin, it is possible to reduce clogging of the discharge hole due to metal deposition and to shorten the processing time of the anodizing process. Moreover, there is no need for maintenance due to clogging. Furthermore, the resin is excellent in acid resistance, so it is not easily affected by the electrolyte and is not easily deteriorated. The discharge hole 25 is embedded in the electrode body 23.

  The electrode body 23 is made of SUS316, and has a stepped cylindrical shape with two outer peripheral portions as shown in FIGS. The electrode body 23 is open to the ring-shaped lower surface 231 of the body 32 and communicates with the eight inflow holes 233 extending in the axial direction (up and down direction in FIG. 4) of the electrode body 23 and the inflow holes 233. A discharge hole portion 25 having eight discharge holes 234 extending in the radial direction of the electrode main body 23 (left and right direction in FIG. 4) and opening in the inner peripheral surface 232 of the main body 32 is provided. The inflow holes 233 are located at the same positions as the eight through holes 226 (in FIG. 10) provided in the intermediate plate 22 so that the through holes 226 of the intermediate plate 22 and the inflow holes 233 of the electrode body 23 communicate with each other. It becomes an electrolyte passage. Note that the hole 234 on the inner peripheral surface 232 side of the inflow hole 233 serves as a discharge hole for the electrolyte solution, and both of them open toward the axis of the electrode body 23. For this reason, electrolyte solution is discharged toward an axial center in a horizontal direction. Further, since the conductor 24 is provided on the intermediate plate 22, the electrode main body 23 is electrically connected to the energizing means 5 through the conductor 24 when being fitted to the intermediate plate 22.

  The shape of the discharge hole 25 is a cylindrical shape as shown in FIGS. 6 and 7, and communicates with the electrolyte solution passage hole 226, and the outer periphery of the discharge hole portion 25 on the side into which the electrolyte solution flows (lower side in FIG. 6) The length 26 is set to be larger than the outer peripheral length 27 on the opposite side (upper side in FIG. 6). The second electrode body 23 is provided with a space along the shape of the discharge hole 25, and the discharge hole portion 25 is embedded in the space to prevent the discharge hole portion 25 from coming off from the second electrode portion 2. it can. Although the two-stage-shaped discharge hole portion 25 is shown in FIG. 6, a shape that becomes narrower toward the discharge hole 234 may be used (not shown). Even if the second electrode main body 23 is not provided with a space that follows the shape of the discharge hole 25, the second electrode portion is formed by the discharge hole 25 on the side into which the electrolyte flows (lower side in FIG. 6). Any structure can be used as long as it can be prevented from coming off from 2. For example, the space of the second electrode body 23 is made straight, and only the portion having the outer peripheral length 27 of the discharge hole 25 is embedded in this space, and the inflow side portion of the electrolyte solution having the outer peripheral length 26 is outside the space. You may comprise so that it may be located and may contact | abut to the lower surface 231 of the electrode main body 23. FIG. According to this configuration, the portion having the outer peripheral length 26 of the discharge hole portion 25 abuts and engages with the lower surface 231 of the electrode body 23, thereby preventing the discharge hole portion 25 from coming off from the second electrode portion 2. Alternatively, the discharge hole portion 25 may be pressed with a pin for preventing disconnection.

  Further, as shown in FIG. 7, at least a part of the side peripheral surface of the discharge hole portion 25 is chamfered. Thereby, the discharge hole part 25 does not rotate with respect to the 2nd electrode 2 at the time of liquid feeding of electrolyte solution. The passage (discharge hole 234) is formed by drilling after incorporating the discharge hole portion 25 into the electrode body 23.

  As shown in FIG. 1, the electrolytic cell 3 having the second electrode portion 2 is made of vinyl chloride or SUS316, is a container having an opening at the upper end, and further supplies the electrolytic solution collected at the bottom of the electrolytic cell 3. 4 is provided with a collection port 31 for collection.

  The electrolytic solution supply means 4 is a cooling tank 41 that cools the electrolytic solution collected from the electrolytic tank 3, a pump 43 that is a driving means that sends out the electrolytic solution, and a flow rate that is a flow rate control means that controls the flow rate of the electrolytic solution. It is composed of a total 44 and a pipe 45 for feeding an electrolyte solution pumped from the pump 43. Further, the cooling tank 41 is provided with a sub-tank 411 for storing the electrolyte, a refrigerator 412 that is a means for cooling the recovered electrolyte, and a temperature sensor 413 that constitutes a control means for controlling the temperature of the electrolyte. It has been.

  The energizing means 5 is means for applying a voltage between the electrode body 23 and the piston W held by the holding means 1 and is composed of an ammeter, a voltmeter, a rectifier (not shown), and the like.

  Further, in this embodiment, when the electrolyte is supplied from the discharge hole 234 of the second electrode body 23, the shape and size of the discharge hole 234 affects the effect of the anodizing treatment, so that it is formed in a circular shape. When the anodizing treatment is actually performed, the discharge hole 234 can be formed into an elliptical shape or a rectangular shape depending on circumstances. Further, as long as the uniformity of the discharge holes 234 of the second electrode body 23 is ensured, the discharge holes 234 can be arranged in a plurality of sets on the inner peripheral surface of the second electrode body 23.

  In the embodiment, when the electrolytic solution is supplied from the discharge hole 234 to the surface of the top outer peripheral surface including the piston ring groove W1 on the top side of the piston W that is the object to be processed, the inner peripheral surface 232 of the electrode body 23 and The distance from the piston ring groove W1 constituting the surface to be processed affects the effect of the anodizing process. If the surface to be processed is too close to the inner peripheral surface 232 of the electrode main body 23 to be the cathode, there is a possibility that a short will occur. On the other hand, if the distance between the surface to be processed and the inner peripheral surface 232 of the electrode body 23 is too large, the electrolytic solution does not effectively reach the surface to be processed, and the anodizing treatment becomes insufficient. Therefore, the distance between the surface of the top outer peripheral surface including the two piston ring grooves W1 on the top side of the piston W connected to the anode and the discharge hole 234 of the electrode body 23 is 2.0 to 15.0 mm. preferable.

  Further, when the electrolytic solution is supplied, the rotating means for rotating the holding means 1 for holding the piston W is provided for the problem that the portion facing the discharge hole 234 is strongly jetted and the formed alumite film is not uniform. Since the speed reduction motor 11 is provided, the alumite film can be uniformly formed by supplying the electrolyte while rotating the piston W.

  The substrate 21 is made of SUS316, and as shown in FIG. 8 and FIG. 9 in the longitudinal sectional view and the plan view, respectively, it is a rectangular plate shape with rounded four corners. A tunnel-like passage 212 having one end opened at the center and the other end opened on the side surface is provided.

  The middle plate 22 is made of vinyl chloride, and its longitudinal sectional view and plan view are shown in FIGS. 10 and 11, respectively. As shown in FIGS. And a stepped ridge 225 which forms a deep circular groove 223 and a shallow circular groove 224 coaxial with the deep circular groove 223 in the central portion on the upper surface side. Further, through holes 226 having both ends opened are formed in the circular recess 221 on the lower surface side and the shallow circular groove 224 on the upper surface side. Eight of the through holes 226 are provided in a ring shape with equal intervals. Further, the intermediate plate 22 incorporates a conductor 24 that is exposed from the outer peripheral surface thereof to the deep circular groove 223.

  Next, the route of the electrolytic solution when anodizing the aluminum-based metal part will be described. The flow rate of the electrolytic solution cooled in the cooling tank 41 incorporated in the supply unit 4 is controlled by the flow rate control unit 44 and sent to the electrolytic cell 3 by the circulation pump 43. The electrolyte rises from the tunnel-shaped passage 212 of the substrate 21 in the electrolytic cell 3 to the chamber formed between the upper surface side recess 211 of the substrate 21 and the lower surface side recess 221 of the intermediate plate 22, and the through hole 226 of the intermediate plate 22 and the electrode body 23 passes through the electrolyte passage composed of the 23 through holes 233 and is supplied from the discharge hole 234 to the outer peripheral surface of the top portion including the piston ring groove W1. Furthermore, after the electrolytic solution is supplied from the discharge hole 234 and anodized, it accumulates in a liquid container of a small container composed of the electrode main body 23 and the middle plate 22 and overblows upward. The overflowing electrolyte solution passes through the outside of the electrode unit 2 and is collected by the supply means 4 through the collection hole 31 at the bottom of the electrolytic cell 3. It is cooled by the cooling means 412 held by the supply means 4 and sent to the electrolytic cell 3 again.

  As described above, according to the anodizing apparatus of the present embodiment, the anodizing apparatus can be downsized by embedding the resin discharge hole 25 in the electrode body 2 of the second electrode part 2. In addition, the clogging of the discharge holes 234 can be reduced and the processing time of the anodizing process can be shortened.

  Furthermore, since the discharge hole portion 25 is formed of an acid-resistant resin, the discharge hole portion 25 is hardly affected by the electrolytic solution and is not easily deteriorated.

  Furthermore, since the discharge hole 25 is prevented from coming off from the second electrode part 2 particularly when the electrolytic solution is supplied, a stable electrolyte solution can be obtained from the discharge hole 234 with respect to the piston W as the object to be processed. Supply can be made.

  Furthermore, it is possible to prevent the discharge hole portion 25 from coming off from the second electrode portion 2 by forming the discharge hole portion 25 so that the outer peripheral length on the lower side is larger than the outer peripheral length on the upper side. It is said. Therefore, it is possible to prevent the discharge hole portion 25 from coming off from the second electrode portion 2 with a simple configuration, and it is possible to reduce the cost.

  Furthermore, since the discharge hole portion 25 is disposed so as not to rotate with respect to the second electrode portion 2, it is possible to stably supply the electrolyte from the discharge hole 234 to the piston W that is the object to be processed. it can.

  Further, by chamfering the discharge hole portion 25, the rotation of the discharge hole portion 25 with respect to the second electrode portion 2 can be prevented. Therefore, the rotation of the discharge hole portion 25 relative to the second electrode portion 2 can be performed with a simple configuration, and the cost can be reduced.

  In the embodiment, the piston is exemplified as the object to be processed, but the present invention is not limited to this. The object to be processed may be a metal part.

  As mentioned above, although this invention was demonstrated according to the said embodiment, this invention is not limited only to the said aspect, The various aspect according to the principle of this invention is included.

Functional explanatory diagram of the anodizing apparatus of the present invention Electrode longitudinal section Electrode plan view Electrode body longitudinal section Electrode body plan view External view of discharge hole Bottom view of discharge hole Board longitudinal section Board plan Middle plate longitudinal section Middle plate plan view

Explanation of symbols

1: holding means, 11: reduction motor, 12: holding shaft,
W: workpiece (piston), W1: first groove, W2: second groove, W3: third groove, W5 masking,
2: second electrode part, 21: substrate, 22: middle plate, 23: electrode body, 24: conductor, 25: discharge hole part,
233: inflow hole, 234: discharge hole, 226: through hole,
3: Electrolysis tank, 4: Supply means, 41: Cooling tank, 412: Cooling means,
413: Temperature control means, 43: Pump, 44: Flow rate control means, 45: Pipe

Claims (6)

A first electrode portion for passing a current through a metal workpiece;
A second electrode portion having a discharge hole portion having a discharge hole facing the object to be processed;
An electrolyte supply means for supplying an electrolyte from the discharge hole toward the object to be processed;
Energization means for applying a voltage to the first electrode portion and the second electrode portion;
In an anodizing apparatus having
The main body of the second electrode part is formed of a metal member, the discharge hole part is formed of a synthetic resin, and the discharge hole part is embedded in the metal member. The anodizing apparatus according to claim 1,
The discharge hole portion is prevented from being detached from the second electrode portion. In the anodizing apparatus according to claim 1 or 2,
The discharge hole has a passage through which the electrolyte flows from the electrolyte supply means to the discharge hole,
The outer peripheral length of the discharge hole on the side where the electrolyte flows into the discharge hole is larger than the outer peripheral length on the opposite side. In the anodizing apparatus according to claim 1 to 3,
The discharge hole portion is disposed so as not to rotate with respect to the second electrode portion.   5. The anodizing apparatus according to claim 1, wherein at least a part of a side peripheral surface of the discharge hole portion is chamfered. The anodizing apparatus according to any one of claims 1 to 5,
The discharge hole is made of an acid resistant resin.

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