JP2008001964A - Method for producing valve plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a valve plate where, even if the valve plate has a complicated shape, its shape can be obtained by hot die forging, its quality such as strength, wear resistance, seizure resistance or the like can be improved, further, not only a hole with a complicated shape can be molded, but also, the molding can be performed to a state close to the almost final shape in a short time, the reduction of cost can be realized by the remarkable reduction of the number of stages, further, since only a copper alloy is used, its recycling is more easier than the case of a bimetal as a composite material. <P>SOLUTION: A copper alloy having a composition comprising, by mass, 20 to 45% Zn, and further comprising one or more elements selected from 0.5 to 6% Mn, 0.5 to 4% Si, 0.01 to 2% Sn, 0.01 to 5% Pb, 0.01 to 4% Bi, 0.01 to 3% Fe, 0.01 to 5% Ni, 0.01 to 3% Co, 0.01 to 3% Ti, 0.01 to 2% Mo, 0.01 to 1% Cr, 0.01 to 2% Zr, 0.01 to 1% Nb and 0.01 to 1% V, and the balance Cu with inevitable impurities is used as the stock, and is subjected to hot forging, and, by the hot forging, its shape is finished. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a valve plate that is disposed in a housing of a hydraulic drive device such as a hydraulic pump or a hydraulic continuously variable transmission and constitutes a part of a fluid passage.

  The valve plate is an indispensable mechanical component in hydraulic drive devices such as excavator loaders and yumbo construction machines and agricultural tractors, and it has strength, wear resistance, and seizure resistance for smooth suction and discharge of oil. Sex is required. Further, in order to ensure various functions, for example, a noise reduction function, a complicated shape is added to a through hole or the like provided in the end face of the valve plate.

  Conventionally, a valve plate obtained by subjecting a copper alloy casting to full-surface machining or a bimetal subjected to press working has been widely used. Among them, in the case of casting, in order to obtain a complicated shape, a copper alloy ingot was used as a raw material, an original product was made by casting, and the final finish was machined by cutting to form details.

  However, cast products have a non-uniform metal structure and lack of stickiness, and as a result of lack of tensile strength and sliding properties, there are situations in which they cannot be used, and in particular, the operating conditions of hydraulic drive units become increasingly severe. On the other hand, valve plates manufactured from conventional casting materials such as continuous casting often have troubles such as breakage and cracks due to metal fatigue due to insufficient strength and sliding characteristics. In addition, when using a casting material such as continuous casting, especially through holes with complicated shapes provided on the end face of the valve plate must be machined entirely, and the strength under conditions of use under high loads There are many cases where there is a concern about the shortage, and since it is a whole surface machining, there is a disadvantage that the cutting cost is high and the machining time is long, so that the cost is high and the delivery time is long.

  Cold press products made of bimetal are less expensive than all-processed products that require such cutting, but have problems of insufficient wear resistance and seizure during initial operation. In addition, bimetal products are a composite material of iron and copper, and are extremely difficult to recycle. Therefore, the burden on the global environment at the time of disposal is large. In addition, since bimetal products are cold-pressed, the material tends to remain distorted and easily deforms due to sliding heat during use, and the deformed sliding surface comes into contact with the mating material. There was a risk of problems such as wear.

  So, even if the valve plate has a complicated shape, this shape can be obtained by hot die forging, improving the quality of strength, wear resistance, seizure resistance, etc. Of course, it can be molded in a short time to a state close to the final shape, cost can be reduced by drastically reducing man-hours, and since only copper alloy is used, it is more than bimetal, which is a composite material. It was an object to provide a method for manufacturing a valve plate that can be easily recycled.

  In order to solve the above-mentioned problems, the invention of claim 1 includes, in mass%, Zn: 20 to 45%, Mn: 0.5 to 6%, Si: 0.5 to 4%, Sn: 0.01-2%, Pb: 0.01-5%, Bi: 0.01-4%, Fe: 0.01-3%, Ni: 0.01-5%, Co: 0.01 -3%, Ti: 0.01-3%, Mo: 0.01-2%, Cr: 0.01-1%, Zr: 0.01-2%, Nb: 0.01-1%, V : Hot forging with a copper alloy having at least one element from 0.01 to 1%, the balance being Cu and inevitable impurities, and finishing the shape by hot forging A method for manufacturing a valve plate is provided.

  Further, the invention of claim 2 contains, by mass%, Zn: 20 to 45%, Al: 0.5 to 6%, Mn: 0.5 to 6%, Si: 0.5 to 4 %, Sn: 0.01 to 2%, Pb: 0.01 to 5%, Bi: 0.01 to 4%, Fe: 0.01 to 3%, Ni: 0.01 to 5%, Co: 0 0.01 to 3%, Ti: 0.01 to 3%, Mo: 0.01 to 2%, Cr: 0.01 to 1%, Zr: 0.01 to 2%, Nb: 0.01 to 1% , V: hot forging with one or more elements from 0.01 to 1%, the remainder being Cu and inevitable impurities as a material, and finishing the shape by hot forging A valve plate manufacturing method is provided.

  According to said structure, the shape could be finished to the detail of the valve plate by hot forging. This is considered to be because the copper alloy having the above composition generates excellent deformability based on stickiness and slidability in hot forging. In addition, the hot forged product showed improvement in strength, particularly tensile strength, wear resistance, and seizure resistance.

  The reason for adding each of the main elements will be described. Mn removes (deoxidizes) oxygen in the molten metal, improves the flow of the molten metal and the quality of the molten metal, and improves the ductility. Mn in the alloy crystallizes uniformly in the matrix and improves the wear resistance of the alloy. Furthermore, the elements consisting of Ni, Si, Al, Sb group, and Fe, Co, Ti, Mo, Cr, Zr, Nb, V group are combined in whole or in part to form an intermetallic compound, wear resistance Greatly improved. When the amount of each element added is less than a predetermined amount, the strength of the alloy is reduced. When the amount is more than the predetermined amount, a hard spot is generated and the machinability is impaired.

  Addition of Ni, Si, and Al groups strengthens the matrix and combines with Mn or Fe, Co, Ti, Mo, Cr, Zr, Nb, and V groups to produce hard intermetallic compounds and wear resistance. Improve seizure resistance. When the added amount is larger than the predetermined amount, a hard spot is generated, and the machinability and wear resistance are impaired. When the amount is less than the predetermined amount, the strength of the alloy is lowered and the sliding characteristics are impaired.

  Regarding the addition of Fe, Co, Ti, Mo, Cr, Zr, Nb, and V groups, the crystal grains are refined, the elongation is improved, and the hard intermetallic compound is combined with Mn or Ni, Si, and Al groups. Produces and improves wear resistance. When the added amount is larger than the predetermined amount, a hard spot is generated, and the machinability and wear resistance are impaired. When the amount is less than the predetermined amount, wear resistance is impaired due to coarsening of crystal grains and reduction of intermetallic compounds.

  In the invention of claim 2, the addition of Al serves to deoxidize the molten metal, thereby preventing the occurrence of casting defects and at the same time improving the strength of the material. The effect is suitably achieved at 0.5 to 6%. In addition, it combines with Mn, Si, Fe, Ni, Co, Ti, Mo, Cr, Zr, Nb, V and the like to produce a hard intermetallic compound and improve wear resistance. When the amount of Al added is larger than a predetermined amount, a fragile γ phase is precipitated. When the amount is less than the predetermined amount, the strength of the alloy decreases.

  As described above, the present invention improves the tensile strength, wear resistance, and seizure resistance by hot forging a copper alloy, and has a final shape as well as a complicated hole. It can be molded to a close state in a short period of time, and cost reduction can be realized by drastically reducing man-hours. Also, because only copper alloy is used, it is easier to recycle than bimetal as a composite material. There is an effect.

  Next, an embodiment of the present invention will be described.

  FIG. 1 is a front view of a valve plate P mounted on a hydraulic unit. The valve plate P is currently in a normal shape as shown in the figure, and a complicated shape such as an outer cutout portion 1, a notch portion 2, a eyelet hole portion 3, an inner diameter cutout portion 4 is applied to the annular plate. ing. Conventionally, since these complicated shapes are formed by cutting after casting, the processing time is long and the cost is high.

  In the present invention, a complicated shape such as the outer diameter notch portion 1, the notch portion 2, the eyelet hole portion 3, and the inner diameter notch portion 4 is formed by die forging, so that it is formed in a short time to a state close to the final shape. It became possible. Therefore, a significant man-hour reduction and cost reduction can be realized. Table 1 shows the chemical components of the copper alloy material of the six types (1 to 6) of the valve plate P used for hot forging in the present invention, and the five types (A to E) used in conventional continuous casting. It shows at the same time compared with the chemical composition of the copper alloy material of the valve plate.

Test pieces were collected for each valve plate from the valve plate bodies of 1 to 6 examples manufactured in the above embodiment and the valve plate bodies of examples A to E manufactured by the conventional casting method. A tensile test (Table 2), a seizure resistance test and an abrasion resistance test (Table 3) were conducted. In addition, about the tensile test, the test piece was set as the JIS 14A No. test piece by the JIS Z2241 metal material tensile test method.

  It can be seen from Table 2 that the valve plate of the present invention is superior in tensile strength (stickiness) to the comparative product. Can be caught.

  As the wear test piece, a ring-on-disk type thrust friction wear tester is used. The test conditions are a seizure resistance evaluation test and an abrasion resistance evaluation test. Lubricating oil is ATF oil with low viscosity and the oil temperature is measured at room temperature. In the seizure resistance evaluation test, an increasing load is applied to a round plate test piece until the counter ring rotating at 6,000 rpm is seized, and the seizure resistance is evaluated based on the seizure load. The higher the value, the better the seizure resistance. In the wear resistance evaluation test, a constant load of 1,000 N is continuously applied for 1 hour at a rotational speed of 6,000 rpm, and the wear mark depth value after the test is evaluated. The smaller the value, the better the wear resistance. Thus, it can be seen from Table 3 that the sliding characteristics of the products of the present invention have better seizure resistance and wear resistance than the comparative material.

  And it is thought that the complicated shape from the stickiness, slidability, etc. of the copper alloy material provided in the present invention to the details of the valve plate could be formed at once by hot forging.

As described above, the alloy of the present invention is used as a sliding part that requires the strength of a valve plate, particularly tensile strength, wear resistance, and seizure resistance, which is indispensable for a hydraulic drive device used in hydraulic equipment and construction. Therefore, it is possible to form in a short time to a state close to the final shape, so that significant man-hour reduction and cost reduction can be realized. If this is schematically shown in Table 4, the cost and man-hour can be reduced to about a half. In the same table, the product of the present invention indicates 1 to 6 in the above table, and the all processed product indicates A to E.

It is a front view of the valve plate shape | molded by hot forging as embodiment of this invention.

Claims (2)

  In mass%, Zn: 20 to 45%, Mn: 0.5 to 6%, Si: 0.5 to 4%, Sn: 0.01 to 2%, Pb: 0.01 to 5 %, Bi: 0.01 to 4%, Fe: 0.01 to 3%, Ni: 0.01 to 5%, Co: 0.01 to 3%, Ti: 0.01 to 3%, Mo: 0 One or more elements selected from 0.01 to 2%, Cr: 0.01 to 1%, Zr: 0.01 to 2%, Nb: 0.01 to 1%, V: 0.01 to 1% A valve plate manufacturing method comprising: hot forging using a copper alloy having Cu and inevitable impurities as a raw material, and finishing the shape by hot forging. In mass%, Zn: 20-45%, Al: 0.5-6%, Mn: 0.5-6%, Si: 0.5-4%, Sn: 0.01-2 %, Pb: 0.01 to 5%, Bi: 0.01 to 4%, Fe: 0.01 to 3%, Ni: 0.01 to 5%, Co: 0.01 to 3%, Ti: 0 0.01 to 3%, Mo: 0.01 to 2%, Cr: 0.01 to 1%, Zr: 0.01 to 2%, Nb: 0.01 to 1%, V: 0.01 to 1% A valve plate manufacturing method characterized by hot forging using a copper alloy having one or more elements of the above, the remainder being Cu and inevitable impurities, and finishing the shape by the hot forging.