JP3664100B2 - Aluminum pulley - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an aluminum material plating method for performing surface treatment of an aluminum material by plating and an aluminum pulley surface-treated by the same method.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, aluminum parts that are relatively easy to form have been used in various industrial machines, and it has been desired to reduce the weight of various devices. By the way, although the equipment made from aluminum is preferable in order to improve the weight reduction and heat dissipation, compared with a ferrous metal product, the wear resistance in the sliding contact surface with the counter part connected with this is low, Improvements in maintaining durability have been made.
[0003]
For example, a pulley that transmits the rotational force of a motor of a vehicle and a pulley on the driven side connected via a belt wound around the pulley each have a belt groove. When these pulleys are made of aluminum and used without wear-resistant treatment, the belt grooves are worn due to sludge or the like being caught on the sliding surface of the pulley and belt, and wear when the market life reaches 500,000 to 1,500,000 km. The amount is large and the amount of slippage is large, so that power cannot be transmitted to various auxiliary devices such as a compressor, a fan, and an alternator receiving rotational force via pulleys and belts.
[0004]
For this reason, the aluminum pulley improves the amount of slippage by giving the belt groove wear resistance, and in the case of the aluminum pulley, the heat dissipation is improved and the iron (FC) pulley is improved. It is also possible to extend the belt durability as compared with.
Here, as the abrasion resistance treatment of the belt groove, the aluminum surface is plated, the plating film is given abrasion resistance, or the aluminum surface layer of the belt groove is metallurgically treated with an abrasion resistant material. Although it can be considered, various belt groove plating processes advantageous in terms of workability and cost have been proposed.
[0005]
For example, Japanese Patent Laid-Open No. 10-78114 discloses an aluminum pulley in which a belt groove is subjected to wear-resistant plating. Here, the thickness according to the life of the pulley itself is about 100 to 500 μm. A manufacturing method for forming a plating film is disclosed. Further, Japanese Utility Model Laid-Open No. 64-25563 discloses a pulley in which the belt-wound portion of an aluminum pulley is Ni-P plated to suppress wear due to sludge on the sliding surface of the belt-wound portion. The
[0006]
The Ni-P plating on the aluminum material may be an electroless plating in which Ni-P (metal) ions in the plating solution are deposited on the aluminum material without flowing current by the action of a reducing agent. A current is passed between the anode and the cathode-side aluminum material arranged opposite to the anode in the plating solution in which -P (metal) is dissolved to reduce metal ions in the solution, and Ni-P (metal) is formed on the aluminum material. Electroplating to be deposited is appropriately employed.
[0007]
[Problems to be solved by the invention]
However, Japanese Patent Laid-Open No. 10-78114 discloses the point that the abrasion-resistant plating is applied to a predetermined thickness by electroplating, but does not disclose the type of plating. On the other hand, in Japanese Utility Model Publication No. 64-25563, an aluminum pulley subjected to Ni-P plating (electroless plating) is disclosed. An aluminum material subjected to Ni-P plating similar to that obtained here is disclosed. The aluminum ground is exposed relatively early, and this point is clearer than the results of the comparative test for wear resistance described later, and the wear resistance is not sufficient.
The present invention is based on the above problems and provides an aluminum material plating method capable of sufficiently ensuring the wear resistance of a plating film used for the surface treatment of an aluminum material and an aluminum pulley surface-treated by the same method. Objective.
[0008]
[Means for Solving the Problems]
According to a first aspect of the present invention, in the aluminum pulley provided with a belt groove , the belt groove is formed by electroplating using a composite plating solution in which SiC particles having a particle diameter of 10 to 50 μm are added to an abrasion-resistant plating solution. It is characterized in that a plating film is formed on.
By electroplating the belt groove of the aluminum pulley using a composite plating solution, the surface treatment of the belt groove can be performed relatively easily. Particularly, the eutectoid in which the plating film of the belt groove contains SiC particles having a particle diameter of 10 to 50 μm. Since it becomes a mixture, sufficient wear resistance can be maintained, and the surface of the belt groove can maintain wear resistance for a relatively long period of time due to the heat dissipation of the aluminum material.
[0009]
Preferably, the plating solution is a Ni-P based plating solution. In this case, since the Ni-P-based plating solution is used as the wear-resistant plating solution, it is relatively easy to reduce the cost, and it is possible to relatively easily form a plating film in a state where SiC particles are mixed.
Preferably, the composite plating solution is obtained by adding and dispersing SiC particles in a volume ratio of 4% to 6%. In this case, the wear resistance of the plating film that becomes a eutectoid mixture containing SiC particles formed by electroplating is further improved.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 show an aluminum pulley as an embodiment of the present invention. This aluminum pulley is a crank pulley (hereinafter simply referred to as a pulley) 1 of an engine (not shown) that is a motor for a vehicle, and a belt 2 wound around the pulley is a driven pulley such as a compressor, a fan, and an alternator (not shown). It is wound around (not shown).
The pulley 1 is formed by re-gravity casting, gravity casting, or die casting, which includes a cylindrical portion 3 and a mounting wall portion 4 continuously formed at one end in the direction X of the rotation center line L, and is then machined and shown in FIG. Made in shape.
[0012]
A plurality of V-shaped belt grooves 5 are formed on the outer peripheral surface of the cylindrical portion 3 of the pulley 1, and V belts 2 arranged in parallel in the rotation center line direction X are respectively wound around the belt portion 5. The mounting wall 4 is formed with a central hole 6 concentrically with the rotation center line L, and a plurality of bolt holes 7 (one shown in FIG. 1) are formed in the vicinity of the outer peripheral edge along the circumferential direction. The mounting wall 4 of the pulley 1 is disposed concentrically with a crankshaft 8 of an engine (not shown), and the two are fastened by bolts inserted into the bolt holes 7.
The belt groove 5 of the pulley 1 is composed of left and right inclined walls 501 and 502 and a low wall 503 connecting the deepest portions thereof, and the entire belt groove is covered with a plating film f having a thickness of about 30 μm.
[0013]
As shown in FIG. 3, the plating film f is a composite plating film made of a eutectoid mixture containing SiC particles 9 in the Ni—P-based plating film.
Here, the plating method of the pulley 1 of the present invention will be described along the pulley manufacturing process.
As the material of the pulley 1, ADC12 or ADC14 which is an Al-Si-Cu-based aluminum alloy for die casting is selected and die-cast.
[0014]
Next, the surface portion of the pulley 1 is cut by a cutting machine so as to maintain a predetermined dimension, and the shape shown in FIG. 1 is manufactured.
Next, the entire surface of the belt groove 5 including the left and right inclined walls 501 and 502 and the low wall 503 connecting the deepest portions thereof is subjected to surface treatment by electroplating.
In electroplating, pretreatment I, electroplating step II, and posttreatment III are performed.
In the pretreatment I, a degreasing process, a pickling process, a masking process other than the belt groove 5 of the pulley 1 and a washing process are performed.
[0015]
In electroplating process II, a Ni-P plating solution as an anti-abrasion plating solution, that is, a conductive salt, a buffering agent, and an additive are added to the Ni-P salt to be plated. SiC particles 9 having a volume ratio of 5% with respect to the plating solution were mixed and dispersed to obtain a composite plating solution.
Here, the SiC particle 9 takes into consideration the particle size of the sand dust caught in the belt 2, the thickness of the plating film f, the belt material (here, rubber belt), etc., and here, the particle size is 20 μm (the particle size of the sand dust, for example, 10 to 50 μm) was used.
The electroplating of the pulley 1 is performed in such a plating tank in which the composite plating solution is accommodated. Here, a plating time corresponding to the thickness of the plating film f reaching 30 μm, here 0.5 to 1.0. It was plated over time.
As a result, a composite plating film of a eutectoid mixture containing SiC particles 9 in the Ni-P-based plating film f was formed in the belt groove 5 with a thickness of 30 μm.
Thereafter, in post-treatment III by electroplating, washing treatment and corrosion resistance enhancement (chromate treatment) are performed, and the electroplating treatment is completed.
[0016]
Since the belt groove 5 of the pulley 1 is thus surface-treated with the plating film f, the plating film f has a hardness of Ni-P based plating film itself of 600 Hv and SiC particles 9 itself of 2000 Hv. It is considered that these can act in combination. That is, the hardness of the SiC particle 9 portion can act on sand dust having a relatively large particle size, and the hardness of the Ni-P-based plating film f portion is mainly used on sand dust having a relatively small particle size. The hardness was apparently increased sufficiently.
For this reason, wear resistance can be maintained for a relatively long period of time, and the film thickness and film density of the plating film f can be easily adjusted for electroplating. It is easy to produce a thickness, and it can be produced at a relatively high density.
[0017]
Next, the wear resistance of the pulley 1 having the belt groove 5 covered with the plating film f generated by electroplating of the composite plating solution according to the present invention will be described using a test specimen described below.
Here, the present invention in which the plated coating f according to the present invention is generated on an aluminum disk-shaped test body (made of ADC 12 which is the same material as the pulley 1) 22 using the abrasion resistance tester 21 of FIG. The aluminum test body A, a comparative aluminum test body (not shown) obtained by performing other surface treatment on the disk-shaped aluminum test body 22 of the same shape and the same material, and a reference test body (not shown) made of the same shape iron The results of each wear resistance test are described below.
[0018]
The wear resistance testing machine 21 of FIG. 4 includes a test specimen rotating mechanism 23 and a grindstone pressing mechanism 24 disposed on the upper part of the test specimen rotating mechanism 23, and these are supported by a machine frame (not shown).
The specimen rotating mechanism 23 functions to attach the aluminum specimen 22 so as to be rotatable around the vertical line H and rotate it at a constant speed. Here, the rotation speed of the aluminum test body 22 was set to 500 rpm.
[0019]
The grindstone pressing mechanism 24 can selectively support the grindstone 25 with the shaft, move the grindstone 25 with the shaft to the retreat position p1 and the press-contact position p2, and the front grindstone surface with respect to the specimen surface (plating film f, etc.). It functions so as to be pressed and supported with a predetermined pressing force. In the grindstone 25 with a shaft, since the cause of the abrasion of the belt groove 5 is due to sand dust caught by the belt 2, a grindstone having a grain size approximately the same as that of sand dust, for example, 1 to 50 μm is selected. The pressing force was performed by adding a constant value, for example, 5 kg.
[0020]
The aluminum test body A of the present invention is produced by electroplating the disc surface with a composite plating solution, the thickness of the plating film f is 30 μm, and the hardness is 600 Hv for the Ni-P based plating film itself, SiC particles 9 It is 2000 Hv itself, and these act in combination as described above.
In the first comparative aluminum test body B, the disk surface was hard anodized to produce an anodized film, the film thickness of the surface treatment layer was 20 μm, and the hardness was 270 to 400 (Hv). It was.
[0021]
In the second comparative aluminum test body C, the aluminum test body 22 was subjected to a hard chrome plating treatment, in which a chrome plating film was formed to 5 μm, and the hardness was 800 (Hv).
[0022]
In the third comparative aluminum test specimen D, the disk surface is chemically plated with a Ni-P-based electroless plating solution, and the thickness of the electroless Ni-P plating film of the surface treatment layer is 20 μm, and the hardness Was 600 (Hv).
The fourth reference specimen E was formed as an iron disk with the same shape as the other comparative aluminum specimens, the disk surface was untreated, and the hardness was 250 (Hv).
[0023]
The results of the comparison of the wear resistance of the above-described four comparative specimens B to E and the aluminum specimen A of the present invention covered with the plating film f according to the present invention by the abrasion resistance tester 21 of FIG. Met.
First, here, a wear resistance test for 2 hours was performed by the fourth reference specimen E, and the change with time of the wear depth (μm) was as shown by ● in FIG. This abrasion resistance characteristic was adopted as the reference characteristic here.
On the other hand, the comparative aluminum specimen B treated with hard alumite progressed excessively within a few minutes as indicated by the black square, the aluminum ground was exposed, and it was NG.
[0024]
The second comparative aluminum specimen C subjected to the hard chrome plating was excessively worn after several tens of minutes as indicated by the □ marks, and the aluminum ground was exposed and was NG. Here, the thickness of the plating film was 5 μm, but it is estimated that the wear resistance can be improved by producing up to about 20 μm. Without being in a favorable environment, the above values are listed here as reference data.
The third comparative aluminum test specimen D subjected to the electroless plating treatment of Ni-P system showed that the wear progressed excessively after 30 minutes as indicated by a circle, the aluminum ground was exposed, and NG. It was.
[0025]
On the other hand, the aluminum test specimen A of the present invention, as indicated by the asterisk (*), stopped at 20 μm in the 2-hour wear resistance test, and during that time, the wear depth of the fourth reference specimen D (●) It was always kept smaller than the mark), and sufficient wear resistance was maintained. This is a eutectoid mixture in which the composite plating film f contains SiC particles, where the Ni-P-based plating film having a hardness of 600 Hv and the SiC particles having a hardness of 2000 Hv act in combination as described above, It seems that the relatively high coating density due to electroplating increased the hardness and ensured sufficient wear resistance.
[0026]
In the above description, the pulley 1 was a crank pulley, but the present invention is similarly applied to other pulleys of compressors, fans, alternators, and other industrial equipment to improve wear resistance. It can also be made.
[0027]
【The invention's effect】
As described above, according to the present invention, the belt groove of the aluminum pulley is electroplated using the composite plating solution, so that the surface treatment of the belt groove can be performed relatively easily. Since it becomes a eutectoid mixture containing SiC particles of -50 μm, it can maintain sufficient wear resistance and maintain the wear resistance of the belt groove surface for a relatively long period of time due to the heat dissipation of the aluminum material. Can do.
[Brief description of the drawings]
FIG. 1 is a cutaway cross-sectional view of a main part of an aluminum pulley as one embodiment of the present invention.
2 is an enlarged cross-sectional view of a belt groove of the aluminum pulley of FIG. 1. FIG.
3 is a schematic cross-sectional configuration diagram of a plating film on the belt groove of FIG. 2;
4 is a schematic cutaway perspective view of an abrasion resistance tester used for the abrasion resistance test of the aluminum pulley of FIG. 1. FIG.
5 is a wear resistance characteristic diagram of the aluminum test specimen of the present invention corresponding to the aluminum pulley of FIG. 1 and other comparative test specimens.
[Explanation of symbols]
1 Pulley (aluminum material)
2 Belt 5 Belt groove 9 SiC particle f Plating film

Claims (1)

In an aluminum aluminum pulley provided with a belt groove, a plating film is formed on the belt groove by electroplating using a composite plating solution obtained by adding SiC particles having a particle size of 10 to 50 μm to an abrasion-resistant plating solution. Aluminum pulley characterized by

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