WO2018039853A1

WO2018039853A1 - Hydraulic pilot valve body casting and mould therefor

Info

Publication number: WO2018039853A1
Application number: PCT/CN2016/097128
Authority: WO
Inventors: 丁先华
Original assignee: 丁先华
Priority date: 2016-08-29
Filing date: 2016-08-29
Publication date: 2018-03-08

Abstract

Disclosed are a hydraulic pilot valve body casting and a mould therefor. The valve body casting comprises a valve main body (1) and a valve body seat (2). The valve main body (1) is cylindrical in shape; and the valve body seat (2) is square in shape. Seven vertical flow channels (3) are provided inside the valve main body (1). Seven flow channel ports (4), corresponding to the seven vertical flow channels (3), are provided on the top of the valve main body (1). A sand core of the mould is assembled from a main sand core and a plurality of small sand cores. The main sand core comprises a left sand core and a right sand core. An inner part, formed by bonding the left sand core and the right sand core, forms a hollow part for collecting gases. Perpendicular exhaust holes are provided on the top of the small sand cores. An upper end of a mould shell of the mould is provided with a pouring basin and a riser, the bottom of the riser being connected to an upper end of a mould cavity, and a sprue port being connected to a lower end of the mould cavity via a sprue channel, for injecting a casting liquid from the bottom of the mould cavity. The surface of the hydraulic pilot valve body casting has fewer gas holes and the possibility of core crack during casting is lower.

Description

Hydraulic pilot valve body casting and mould thereof

Technical field

The invention relates to the field of valve body castings and moulds thereof, in particular to a hydraulic pilot valve body casting and a mould thereof.

Background technique

The hydraulic pilot valve body casting is mainly used for the hydraulic control system of large loader. As a key component of the hydraulic system of engineering machinery, it has the advantages of high integration, high reliability and long service life, and has a good market prospect. However, China's industry is not strong, and the current situation of overcapacity of medium and low-end products and the high-end hydraulic components are almost completely dependent on imports are urgently needed.

The existing hydraulic pilot valve body castings have the following disadvantages: 1. The casting has more air holes, and the scrap rate caused by the plane air holes reaches 70 or more. The main reason is that the thickness of the sand core in the casting mold is large, and the gas generation amount is large, and the core is connected. The diameter of the sand core is only 5 mm. It is difficult to discharge the gas from the middle sand core to the outside of the mold quickly. A large part of the gas will invade into the mold to produce the pores of the casting. Second, the casting flow path is very complicated and the center The sand core of the part is large, the thickness reaches about 20 mm, and the sand core connecting the sand of the center is very small, and the diameter is only about 5 mm. When the pouring is performed, the sand core is not exhausted and the fine sand core is in the molten iron and the high temperature. The ratio of the lower core is extremely high.

Therefore, it is particularly important to develop a hydraulic pilot valve body casting with a small number of pores and a low core fracture ratio and a mold for producing the casting.

Summary of the invention

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the deficiencies of the prior art and to provide a hydraulic pilot valve body casting and a mold thereof having fewer air holes and a lower core split ratio.

In order to solve the above technical problem, the present invention provides a hydraulic pilot valve body casting, comprising a valve body and a valve body base, the valve body is cylindrical, the valve body base is square, and the valve body is The interior is provided with seven vertical flow passages, and the top of the valve body is provided with seven flow passages corresponding to the seven vertical flow passages.

Preferably, a center of the top of the valve body is provided with a flow passage opening I, and six flow passage openings II are evenly distributed around the flow passage opening I, and six of the flow passage openings II are arranged in a hexagonal shape.

Preferably, the diameter of the flow channel opening I is larger than the diameter of the flow channel opening II.

Further, the valve body and the valve body base are integrally formed by an underfill casting process.

The present invention also provides a hydraulic pilot casting mold comprising a shell type and a sand core, the shell type comprising a left shell type and a right shell type, the sand core being disposed between the left shell type and the right shell type, The left shell type, the right shell type and the sand core are clamped to form a cavity, and the sand core is assembled by a main sand core and a plurality of small sand cores, the main sand core including a left sand core and a right sand core. The inner portion of the left sand core and the right sand core is formed into a hollow portion for collecting gas, and the top of the small sand core is provided with a vertical vent hole; the upper end of the shell type is provided with a sprue cup and A riser, the bottom of the riser being coupled to the upper end of the cavity, the gate being coupled to the lower end of the cavity by a runner for injecting a potting solution from the bottom of the cavity.

Preferably, the riser is a heat riser having a diameter of 80 mm.

Preferably, the sand core is a coated sand core.

The hydraulic pilot valve body casting and the mold thereof of the invention have the following beneficial effects:

1. The hydraulic pilot valve body casting of the invention has a tensile strength of not less than 240 MPa and a hardness of 190 HB-220 HB, and the casting has high integration strength, reliability and long service life.

2. The left sand core and the right sand core of the main sand core of the hydraulic pilot valve body casting mold of the present invention, wherein the left sand core and the right sand core are formed into a hollow portion for collecting gas, and The top of the small sand core is provided with a vertical venting hole. During the casting process, the venting speed of the venting hole is discharged to the outside of the hollow portion, thereby greatly reducing the pores of the casting; in addition, the inner hollow main core reduces the coating. Sand usage and gas production.

3. The gate of the hydraulic pilot valve body casting mold of the present invention is connected to the lower end of the cavity through a runner for injecting the pouring liquid from the bottom of the cavity, so that the molten iron flow is stable and the molten iron is reduced. The sand core breakage caused by the flow is beneficial to the exhaust, ensuring that the suspended cores on both sides are not easily deformed or broken.

4. The riser of the upper end of the shell type of the hydraulic pilot valve body casting mold of the present invention is a heat riser with a diameter of 80 mm, which enhances the feeding effect of the riser, and the cold iron water and the molten iron containing gas and slag overflow into the riser. Reduces slag and porosity defects in the casting.

DRAWINGS

In order to more clearly illustrate the technical solution of the present invention, the following will be described in the embodiment or the prior art. BRIEF DESCRIPTION OF THE DRAWINGS The drawings used in the following description are briefly introduced. It is obvious that the drawings in the following description are only some embodiments of the present invention, and those skilled in the art can also These figures are taken in other figures.

Figure 1 is a plan view of a hydraulic pilot valve body casting of the present invention;

Figure 2 is a cross-sectional view taken along line A-A of Figure 1;

Figure 3 is a cross-sectional view taken along line B-B of Figure 1;

Figure 4 is a cross-sectional view taken along line C-C of Figure 1;

Figure 5 is a side elevational view of the hydraulic pilot valve body casting of the present invention.

Wherein, the reference numerals in the figure correspond to: 1-valve body, 2-valve body base, 3-vertical flow channel, 4-flow channel port, 41-channel port I, 42-channel port II.

detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

1-5, the present invention discloses a hydraulic pilot valve body casting, comprising a valve body 1 and a valve body base 2, wherein the valve body 1 and the valve body base 2 are integrally formed by an underfill casting process. The valve body 1 has a cylindrical shape, the valve body base 2 has a square shape, and the inside of the valve body 1 is provided with seven vertical flow passages 3, and the top of the valve body 1 is provided with The seven flow passages 3 corresponding to the seven vertical flow passages 3; the distribution of the seven flow passage openings is as follows: the center of the top of the valve body 1 is provided with a flow passage opening I41 around the flow passage opening I41 There are six flow passages II42 uniformly distributed, and the six flow passages II42 are arranged in a hexagonal shape, and the diameter of the flow passage opening I41 is larger than the diameter of the flow passage opening II42.

The main technical parameters of the hydraulic pilot valve body casting of the present invention are as follows:

(1) Material: HT300

(2) Body tensile strength: ≥240Mpa

(3) Hardness: HB190-220

(4) Casting defects such as slag inclusion, pores, shrinkage holes, shrinkage, etc.

(5) Single weight: 5.2kg.

The invention also discloses a hydraulic pilot valve body casting mold, comprising a shell type and a sand core, the shell type comprising a left shell type and a right shell type, the sand core being disposed in the middle of the left shell type and the right shell type The left shell type, the right shell type and the sand core are clamped to form a cavity, and the sand core is a coated sand core, which is assembled by a main sand core and a plurality of small sand cores, the main sand core The left sand core and the right sand core are formed, and the inner portion of the left sand core and the right sand core are formed into a hollow portion for collecting gas, and the top of the small sand core is provided with a vertical vent hole, the sand The gas emitted by the core in the heated state gathers in the hollow portion, and the vent hole on the small sand core rapidly discharges the gas emitted from the sand core to the outside of the mold, thereby greatly reducing the pores of the casting.

The upper end of the shell is provided with a gate cup, and the gate is connected to the lower end of the cavity through a runner for injecting the pouring liquid from the bottom of the cavity, that is, by the existing top injection process It is changed to the bottom injection process to make the flow of molten iron smooth, reduce the breakage of the core caused by the turbulent flow of molten iron, and facilitate the exhaust, ensuring that the suspended cores on both sides are not easily deformed or broken.

The bottom casting process casting riser becomes a cold riser, which is not conducive to the feeding. Therefore, a riser is provided at the upper end of the shell type, and the bottom of the riser is connected with the upper end of the cavity, and the riser has a diameter of 80 mm. The hot riser strengthens the feeding effect of the riser, while the cold iron water and the molten iron containing gas and slag overflow into the riser, reducing the slag and porosity defects of the casting.

What has been disclosed above is only the preferred embodiment of the present invention, and of course, the invention may not be limited thereto. The scope of the claims, therefore, equivalent changes made in the claims of the invention are still within the scope of the invention.

Claims

A hydraulic pilot valve body casting characterized by comprising a valve body (1) and a valve body base (2), the valve body (1) is cylindrical, and the valve body base (2) is square The inside of the valve body (1) is provided with seven vertical flow passages (3), and the top of the valve body (1) is provided with corresponding to the seven vertical flow passages (3) Seven runners (4).
The hydraulic pilot valve body casting according to claim 1, wherein a center of the top of the valve body (1) is provided with a flow passage opening I (41), and the circumference of the flow passage opening I (41) is evenly distributed. There are six runners II (42), and six of the runners II (42) are arranged in a hexagon.
The hydraulic pilot valve body casting according to claim 2, wherein the diameter of the flow passage opening I (41) is larger than the diameter of the flow passage opening II (42).
The hydraulic pilot valve body casting according to any one of claims 1 to 3, characterized in that the valve body (1) and the valve body base (2) are integrally formed by an underfill casting process.
A hydraulic pilot valve body casting mold comprising a shell type and a sand core, the shell type comprising a left shell type and a right shell type, the sand core being disposed between the left shell type and the right shell type, the left shell a shape, a right shell type, and a cavity formed by clamping the sand core, wherein

The sand core is assembled by a main sand core including a left sand core and a right sand core, and the left sand core and the right sand core are formed by bonding to form an atmosphere for collecting gas. a hollow portion, the top of the small sand core is provided with a vertical venting hole;

The upper end of the shell is provided with a gate cup and a riser, the bottom of the riser is connected to the upper end of the cavity, and the gate is connected to the lower end of the cavity through a runner for pouring Liquid is injected from the bottom of the cavity.
The hydraulic pilot valve body casting mold according to claim 5, wherein the riser is a heat riser having a diameter of 80 mm.
The hydraulic pilot valve body casting mold according to claim 5 or 6, wherein the sand core is a coated sand core.