Hydraulic piston pump bimetal rotor integral casting process

Abstract

The application discloses a hydraulic plunger pump bimetal rotor integral casting process, comprising the following steps: A, preparing a rotor steel base; B, preparing a bottom mold; C, smelting a copper alloy; D, installing and combining the rotor steel base with the bottom mold; E, pouring and cooling; e1) quickly pouring the smelted copper alloy liquid from the center hole of the rotor steel base; e2) when the copper alloy liquid rises to the end face of the rotor steel base, immediately cooling the bottom mold with flowing water, meanwhile, removing the press iron, and covering the preheated asbestos plate on the end face of the rotor steel base; e3) when the end face of the rotor steel base is dark red, closing the cooling water and naturally cooling to room temperature, thereby obtaining a rotor blank; F, taking out the rotor blank from the bottom mold. The application can effectively improve the production efficiency and is simple to operate.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of bimetal rotor casting processes, especially a kind of hydraulic plunger pump bimetal rotor integral casting process. BACKGROUND

[0002] Plunger hydraulic pump is reciprocated in the plunger hole of the rotor body by the plunger group, and high-pressure fluid is output. When the hydraulic pump works, relative sliding friction occurs between the plunger and the plunger hole, and between the rotor end face and the oil distribution cover. With the development of plunger hydraulic pump towards high speed, high pressure and long service life, higher requirements are put forward for the rotor as the core component. The rotor with single material structure cannot meet the requirements of high strength, high fatigue resistance and excellent friction pair matching characteristics. Copper / steel bimetal has the dual characteristics of copper and steel, taking into account the strength of steel and the friction reduction and wear resistance of copper, which ensures the fatigue resistance and wear resistance of the part. Bimetal casting can better realize the combination of copper / steel bimetal, with less equipment investment. However, the traditional bimetal casting process requires welding a bottom plate to the bottom of the steel base to form a casting system after the steel base is processed, then casting, and then removing the bottom plate by turning after casting. The disadvantages of this method are that the welding of the bottom plate requires high requirements, and in production, the phenomenon of water leakage due to poor welding of the bottom plate or cracking of the weld at high temperature often occurs, and the molten slag in the plunger hole is not easy to remove, so the copper alloy needs to be melted again to help remove the slag after casting, which reduces the production efficiency and prolongs the production cycle. Therefore, the existing technology has the problems of low production efficiency and high operation difficulty. SUMMARY

[0003] The purpose of the present application is to provide a hydraulic plunger pump bimetal rotor integral casting process. The present application not only can effectively improve the production efficiency, but also is simple to operate.

[0004] The technical solution of the present application is a hydraulic plunger pump bimetal rotor integral casting process, comprising the following steps:

[0005] A, preparing the rotor steel base:

[0006] B, preparing the bottom mold:

[0007] C, smelting copper alloy;

[0008] D, assembling the rotor steel base and the bottom mold:

[0009] E, pouring and cooling:

[0010] e1) quickly pouring the smelted copper alloy liquid from the center hole of the rotor steel base;

[0011] e2) when the copper alloy liquid is close to the end face of the rotor steel base, immediately chill the bottom mold with flowing water, remove the pressing iron at the same time, and cover the preheated asbestos board on the end face of the rotor steel base;

[0012] e3) when the end face of the rotor steel base is dark red, close the cooling water and naturally cool it to room temperature, and obtain the rotor blank;

[0013] F, the rotor blank is taken out of the bottom mold.

[0014] In the foregoing hydraulic piston pump bimetal rotor integral casting process, the specific process of step A is:

[0015] a1) sand blasting: sand blasting the rotor steel base to be poured surface to remove surface oil and oxides;

[0016] a2) cleaning: clean the steel base with industrial alcohol;

[0017] a3) plug the positioning hole with refractory insulation fiber and scrape the end face flat;

[0018] a4) preheating: place the rotor steel base in a graphite crucible, and fill the graphite crucible with a protective agent composed of borax and copper solder powder. After the borax and copper solder powder are melted, the rotor steel base should be completely immersed in the molten protective agent, and the temperature should be kept for 1 hour.

[0019] In the foregoing hydraulic piston pump bimetal rotor integral casting process, the specific process of step B is:

[0020] b1) sand blasting: sand blasting to remove oil and oxides in the cavity of the bottom mold;

[0021] b2) spraying: spray graphite paint on the inner cavity of the bottom mold and the end face in contact with the steel base;

[0022] b3) preheating: preheat the mold to 500-600°C before pouring.

[0023] In the foregoing hydraulic piston pump bimetal rotor integral casting process, the specific process of step D is:

[0024] d1) take the mold out of the heating furnace and place it on a flat water tank cover plate;

[0025] d2) take the rotor steel base out of the molten protective agent, drain the surface flowing protective agent, and quickly place it on the bottom mold;

[0026] d3) pre-position a certain weight of pressing iron on the end face of the rotor steel base.

[0027] In the foregoing hydraulic piston pump bimetal rotor integral casting process, the bottom mold comprises a bottom mold body, an inner hole matched with the rotor steel base is arranged on the upper end of the bottom mold body, and a pouring system is arranged below the inner hole.

[0028] In the aforementioned integral casting process of a bimetallic rotor for a hydraulic plunger pump, the single-sided fitting clearance between the inner hole and the rotor steel base is 0.5mm-1.0mm, and the fitting height is 5mm-10mm.

[0029] In the aforementioned integral casting process of a bimetallic rotor for a hydraulic piston pump, the slope of the gating system side is 60° and the height is 10mm-18mm.

[0030] Compared with existing technologies, this invention first immerses the rotor steel substrate completely in a mixture of molten copper solder powder and borax for about one hour, then removes it, drains the surface molten material, and places it on a preheated bottom mold. A pressure iron is added to the top of the rotor, and then the molten copper alloy is quickly poured into the rotor through the central hole. When the copper alloy rises to the top of the rotor, the pressure iron is removed, and an asbestos board is placed on top of the rotor. Simultaneously, the bottom mold is cooled with flowing water, and the rotor blank solidifies sequentially from bottom to top, which is beneficial for venting and slag removal. At the same time, the copper alloy filling of this invention is stable and less prone to air entrapment, which can better remove residual molten borax from the plunger hole. Furthermore, the bottom mold can be reused, reducing the process of welding the bottom plate before casting and removing the bottom plate after casting in traditional methods. It has the advantages of short process flow, simple operation, low cost, and stable quality, and can achieve mass production. Attached Figure Description

[0031] Figure 1 This is a structural view of the rotor steel matrix;

[0032] Figure 2 This is a structural view of the bottom mold;

[0033] Figure 3 This is an assembly view of the rotor steel base and the bottom mold.

[0034] The markings in the attached diagram are as follows: 1-Bottom mold body, 2-Inner hole, 3-Gating system. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0036] Example. A process for integral casting of a bimetallic rotor for a hydraulic piston pump includes the following steps:

[0037] 1. Preparation of rotor steel base:

[0038] Sandblasting: Sandblasting is performed on the surface of the rotor steel substrate to be poured to remove surface oil and oxides;

[0039] Cleaning: Clean the steel substrate with industrial alcohol;

[0040] Block the positioning holes with fire-resistant and heat-insulating fibers and smooth the end face;

[0041] Preheating: Place the rotor steel substrate in a graphite crucible and fill the crucible with a mixture of borax and copper solder powder. After the borax and copper solder powder melt (about 870°C), ensure that the steel substrate is completely immersed in it and keep it at this temperature for about 1 hour.

[0042] 2. Preparation of the bottom mold:

[0043] Sandblasting: Sandblasting removes oil and oxides from the inner cavity of the bottom mold;

[0044] Graphite coating: After the bottom mold is preheated to 200℃~300℃, graphite coating is sprayed on the inner cavity and the end face in contact with the rotor steel substrate.

[0045] Preheating: Before pouring, preheat the bottom mold to 500℃-600℃;

[0046] 3) Copper alloy smelting: Proceed according to the general instructions;

[0047] 4) Assembly of rotor steel base and bottom mold:

[0048] Remove the bottom mold from the heating furnace and place it on a flat water tank cover plate;

[0049] Remove the rotor steel substrate from the molten protective agent, drain off any remaining protective flux, and quickly place it on the bottom mold. Figure 3 As shown.

[0050] To prevent the molten copper alloy from overflowing from the bottom mold during casting, a certain weight of pressure iron is placed on the end face of the rotor steel base beforehand.

[0051] 5) Pouring and cooling:

[0052] The molten copper alloy (pouring temperature 1140℃~1180℃) is rapidly poured into the rotor through the central hole of the steel substrate;

[0053] When the copper alloy liquid rises to near the end face of the rotor steel base, immediately cool the bottom mold with flowing water, remove the pressure iron, and cover the end face of the rotor steel base with a preheated asbestos board.

[0054] The cooling water should be turned off and allowed to cool naturally only when the end face of the rotor steel base turns dark red.

[0055] 6) Remove the rotor:

[0056] Once the rotor has cooled to room temperature, the rotor blank can be removed from the bottom mold.

[0057] Rotor steel matrix structure such as Figure 1As shown. During casting, the rotor distribution surface (large flat surface) faces upward, and the nine plunger holes are connected to the rotor distribution surface. The center hole serves as a sprue. Holes of different diameters within each plunger hole are connected by a 120° chamfer. After the copper alloy liquid is poured in through the center hole, it rises from the bottom of the rotor along the nine plunger holes to the rotor end face, which is beneficial for venting and slag removal from the plunger holes and distribution surface, as well as for feeding the nine plunger holes. The machining allowance for the outer diameter is 5mm-10mm on each side; the machining allowance for the bottom is 3mm-5mm; the riser height is 15mm-20mm; the center hole diameter is Φ15mm-Φ25mm; and the Φ5mm small hole serves as a positioning hole for machining.

[0058] The bottom mold structure for casting is as follows Figure 2 As shown. It includes a bottom mold body 1, with an inner hole 2 at the upper end of the bottom mold body 1 that mates with the rotor steel base. A gating system 3 is located below the inner hole 2. The inner hole mates with the rotor steel base, with a single-sided clearance of 0.5mm-1.0mm and a mating height of 5mm-10mm. If the clearance is too small, it will be difficult to assemble the steel base with the bottom mold after heating, and the rotor will be difficult to remove from the bottom mold after the copper alloy is poured. If the clearance is too large, it will affect the assembly and positioning of the steel base with the bottom mold after heating, and water leakage is likely during pouring on the side with the larger clearance. The bottom section with a 60° slope serves as the gating system, acting as a buffer and slag collector, with a height of 10mm-18mm. The total thickness of the bottom mold is approximately 60mm.

Claims

1. A bimetallic rotor monobloc casting process for a hydraulic piston pump, characterized in that, The method comprises the following steps: A. Preparing a rotor steel base body; B. Preparing a bottom mold; C. Melting a copper alloy; D. Assembling the rotor steel base body and the bottom mold; E. Pouring and cooling; e1) Pouring the melted copper alloy liquid from the center hole of the rotor steel base body quickly; e2) When the copper alloy liquid rises to the end face of the rotor steel base body, immediately chill the bottom mold with flowing water, remove the pressing iron, and cover the preheated asbestos board on the end face of the rotor steel base body; e3) When the end face of the rotor steel base body is dark red, turn off the cooling water and naturally cool it to room temperature to obtain a rotor blank; Taking the rotor blank out of the bottom mold; The specific process of step A is as follows: a1) Sandblasting: sandblasting the rotor steel base body to be poured to remove surface oil and oxides; a2) Cleaning: cleaning the steel base body with industrial alcohol; a3) Blocking the positioning hole with refractory insulation fiber and scraping the end face; a4) Preheating: placing the rotor steel base body in a graphite crucible and filling the graphite crucible with a protective agent composed of borax and copper solder powder. After the borax and copper solder powder are melted, the rotor steel base body should be completely immersed in the protective agent, and the temperature should be kept for 1 hour; The specific process of step B is as follows: b1) Sandblasting: sandblasting to remove oil and oxides in the inner cavity of the bottom mold; b2) Spraying: spraying graphite paint on the inner cavity of the bottom mold and the end face contacting the steel base body; b3) Preheating: preheating the bottom mold to 500-600°C before pouring; The specific process of step D is as follows: d1) Taking the bottom mold out of the heating furnace and placing it on a flat water tank cover plate; d2) Taking the rotor steel base body out of the molten protective agent, draining the surface flowing protective agent, and quickly placing it on the bottom mold; d3) Preparing a certain weight of pressing iron on the end face of the rotor steel base body; The bottom mold comprises a bottom mold body (1), an inner hole (2) on the upper end of the bottom mold body (1) matched with the rotor steel base body, and a pouring system (3) below the inner hole (2); The single-sided fitting gap between the inner hole (2) and the rotor steel base body is 0.5-1.0 mm, and the fitting height is 5-10 mm; The slope of the side of the pouring system (3) is 60°, and the height is 10-18 mm.

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