Valve plate for internal gear pump

Abstract

The invention relates to a valve plate for an internal gear pump, which comprises a base material layer and a contact layer sintered on the base material layer. The contact layer is formed by sintering and rolling alloy powder of copper, tin, nickel, phosphorus and bismuth, and the porosity of the contact layer is 0.1%-0.3%. The percentage content of the nickel is 0.9%-9.0%, the percentage content of the tin is 1.5%-11%, the percentage content of the phosphorus is 0.01%-0.05%, the percentage content of the bismuth is 0.005%-0.08%, and the balance is the copper. According to the valve plate for the internal gear pump, the contact layer is arranged, so that the service life of the valve plate is prolonged, and the corrosion resistance, the wear resistance and the strength of the valve plate are improved. Meanwhile, after sintering and rolling, the porosity is controlled to be 0.1%-0.3%, so that the lubricating property can be ensured while various properties such as strength, toughness, hardness, wear resistance and heat conductivity of the valve plate are ensured.

Description

Technical Field

[0001] The invention relates to the technical field of valve plate manufacturing, in particular to a valve plate for an internal gear pump. Background Art

[0002] Existing internal gear pumps can be primarily categorized as internal involute gear pumps and internal cycloid gear pumps. Both types of internal gear pumps comprise a pump housing assembly and an internal gear assembly. The pump housing assembly houses a working chamber for the internal gear assembly, as well as a liquid inlet and liquid outlet passages, each communicating with the chamber. The internal gear assembly, mounted within the chamber, comprises a rotating shaft, an inner rotor, an outer rotor, and a valve plate. The inner rotor is mounted on the rotating shaft and meshes with the outer rotor to form an internal gear pair. The inner rotor is an internal gear, the outer profile of which forms the inner rotor tooth profile. The outer rotor is typically an integral ring gear, the inner profile of which forms the outer rotor tooth profile. The inner rotor tooth profile meshes with the outer rotor tooth profile. When the internal gear pair is in operation, a low-pressure suction zone, corresponding to the liquid inlet passage, and a high-pressure discharge zone, corresponding to the liquid outlet passage, are formed between the inner and outer rotors. The function of the port plate is to control the flow direction and volume of the fluid by rotating and deflecting according to actual needs. During use, the port plate typically rotates or deflects driven by the inner or outer rotor, so its friction and wear resistance must be guaranteed. Furthermore, the port plate's lifespan must be guaranteed. Therefore, it is usually located inside the gear pump, making it somewhat inconvenient to maintain. Summary of the Invention

[0003] In view of this, the present invention provides a valve plate for an internal gear pump to solve the above problems.

[0004] A valve plate for an internal gear pump includes a base layer and a contact layer sintered onto the base layer. The contact layer is formed by sintering and rolling an alloy powder of copper, tin, nickel, phosphorus, and bismuth. The porosity of the contact layer is 0.1% to 0.3%. The nickel content is 0.9% to 9.0%, the tin content is 1.5% to 11%, the phosphorus content is 0.01% to 0.05%, the bismuth content is 0.005% to 0.08%, and the remainder is copper.

[0005] Furthermore, the substrate layer 10 can be made of steel, copper, and copper alloy.

[0006] Furthermore, in the material of the contact layer, the percentage content of nickel is 1.5% to 2.5%, the percentage content of tin is 1.5% to 2.0%, the percentage content of phosphorus is 0.02% to 0.04%, the percentage content of bismuth is 0.01% to 0.06%, and the rest is copper.

[0007] Furthermore, in the material of the contact layer, the percentage content of nickel is 0.9% to 1.2%, the percentage content of tin is 7% to 9.0%, the percentage content of phosphorus is 0.01% to 0.03%, the percentage content of bismuth is 0.03% to 0.08%, and the rest is copper.

[0008] Furthermore, in the material of the contact layer, the percentage content of nickel is 0.1% to 0.3%, the percentage content of tin is 6% to 7%, the percentage content of phosphorus is 0.11% to 0.17%, the percentage content of bismuth is 0.04% to 0.07%, and the rest is copper.

[0009] Furthermore, in the material of the contact layer, the percentage content of nickel is 7.5% to 9.0%, the percentage content of tin is 6.0% to 7.5%, the percentage content of phosphorus is 0.25% to 0.43%, the percentage content of bismuth is 0.06% to 0.08%, and the rest is copper.

[0010] Furthermore, in the material of the contact layer, the percentage content of nickel is 0.05% to 0.2%, the percentage content of tin is 9% to 11%, the percentage content of phosphorus is 0.11% to 0.17%, the percentage content of bismuth is 0.04% to 0.07%, and the rest is copper.

[0011] Compared to the prior art, the valve plate for an internal gear pump provided by the present invention improves its lifespan, corrosion resistance, wear resistance, and strength by providing the contact layer. Specifically, the alloy powder of copper, tin, nickel, phosphorus, and bismuth is formed by sintering and rolling at a specific temperature. The nickel content is 0.9% to 9.0%, the tin content is 1.5% to 11%, the phosphorus content is 0.01% to 0.05%, the bismuth content is 0.005% to 0.08%, and the remainder is copper. The nickel improves the corrosion resistance of the contact layer, increases the material's hardness, and improves its heat resistance. The tin forms a solid solution in the copper matrix, thereby strengthening the contact layer's structural strength and also enhancing its wear resistance. The phosphorus improves the contact layer's strength, hardness, thermal conductivity, and wear resistance. The bismuth enhances the alloy's strength and hardness, maintaining good dimensional stability in high-temperature environments. At the same time, after sintering and rolling, the porosity is controlled at 0.1% to 0.3%, thereby ensuring various properties of the distribution plate such as strength and toughness, hardness and wear resistance, and thermal conductivity, while also ensuring excellent lubrication performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a structural schematic diagram of a valve plate for an internal gear pump provided by the present invention. DETAILED DESCRIPTION

[0013] The following is a further detailed description of specific embodiments of the present invention. It should be understood that the description of the embodiments of the present invention herein is not intended to limit the scope of protection of the present invention.

[0014] like Figure 1 As shown in FIG. 1 , the present invention provides a valve plate for an internal gear pump, which comprises a base layer 10 and a contact layer 20. The base layer 10 can be made of steel, copper, or a copper alloy. The contact layer 20 is formed by sintering and rolling an alloy powder of copper, tin, nickel, phosphorus, and bismuth at a certain temperature.

[0015] The contact layer 20, formed by sintering, is rolled to a porosity of 0.1% to 0.3%. Because the valve plate is located inside the internal gear pump and frequently rotates and deflects, the porosity should be as low as possible. Lower porosity improves tensile strength and impact toughness, ensuring longevity. A porosity greater than 0.3% can have the following disadvantages: First, strength and toughness are reduced. Porosity, as internal defects within the material, interrupts the continuity of the matrix, leading to stress concentrations and significantly reducing the tensile strength and impact toughness of the material. Second, hardness and wear resistance are reduced: increased porosity reduces the effective load-bearing area and lowers surface hardness. For every 5% increase in porosity, surface hardness can decrease by 10% to 15%. Third, fatigue life is shortened: pores can easily become crack initiation sites under cyclic loading, accelerating fatigue failure. Fourth, thermal conductivity is reduced: pores block the heat flow path. For every 1% increase in porosity, the thermal conductivity of copper-based alloys decreases by approximately 4%. If the porosity is less than 0.1%, the lubricant cannot be stored in the pores due to the surface tension of the lubricant. Therefore, under high temperature conditions, the oil film will rupture, leading to direct metal contact, increased wear, and shortened service life. In addition, when the porosity is limited to 0.1% to 0.3%, the capillary force of the pores can also draw the lubricant to the surface, replenishing the oil film consumed by friction and avoiding dry friction. At the same time, when the porosity is limited to 0.1% to 0.3%, the lubricant in the pores slowly seeps out under high temperature or high pressure to maintain continuous oil film coverage and prevent direct metal contact. This cannot be achieved when the porosity is less than 0.1%.

[0016] In the materials used to make the contact layer, nickel improves the corrosion resistance of the contact layer, increases the material's hardness, and improves its heat resistance. Tin forms a solid solution in the copper matrix, thereby strengthening the structural strength of the contact layer. The presence of tin also improves the wear resistance of the contact layer. Phosphorus improves the strength, hardness, thermal conductivity, and wear resistance of the contact layer. Bismuth increases the strength and hardness of the alloy, allowing it to maintain good dimensional stability in high-temperature environments.

[0017] In the material for preparing the contact layer, the percentage content of nickel is 0.9% to 9.0%, the percentage content of tin is 1.5% to 11%, the percentage content of phosphorus is 0.01% to 0.05%, the percentage content of bismuth is 0.005% to 0.08%, and the rest is copper.

[0018] Because the valve plate acts like a bearing, supporting the cylinder block, it must possess sufficient strength and rigidity to prevent excessive deformation under high pressure and high temperature. Therefore, the addition of bismuth forms hard points on the soft copper matrix. These hard points provide support, and even when the soft matrix is worn and concave, they can still provide support, thereby ensuring the strength of the entire valve plate. The bismuth content should be maintained between 0.005% and 0.08%. A content greater than 0.08% results in too many hard points, preventing the formation of an effective oil film. A content less than 0.005% results in too few hard points, preventing the strength of the contact layer 20. Tin forms a solid solution in the copper matrix, thereby increasing its strength and preventing it from becoming too soft. The tin content should be controlled between 1.5% and 11%. Therefore, the copper matrix must have a certain degree of softness to allow it to wear down during operation, allowing it to store lubricant and form a continuous oil film. If the tin content exceeds 11%, the solid solution formed with the copper matrix is too high, resulting in excessive strength, making it difficult to wear down and form a continuous oil film, thereby reducing the lubrication performance of the port plate. If the tin content is less than 1.5%, the solid solution formed is too low, making the copper matrix too weak and prone to rapid wear, thus reducing the service life of the port plate. The main function of nickel is to improve the corrosion resistance of the contact layer. Its content should be controlled between 0.9% and 9.0%. A content greater than 9.0% is unnecessary, as its corrosion resistance is sufficient at less than 9.0%. A content greater than 9.0% not only fails to improve corrosion resistance, but also affects the copper matrix content, thereby affecting the performance of the entire port plate. A content less than 0.9% results in insufficient corrosion resistance, further reducing the service life of the port plate.

[0019] The primary function of phosphorus is to improve the thermal conductivity of the distributor plate. This is because phosphorus increases the thermal conductivity of the contact layer, making it easier for the heater to transfer heat to the heating medium, thereby improving heating efficiency. The phosphorus content should be controlled between 0.01% and 0.05%. Because phosphorus is somewhat corrosive, excessively high phosphorus content may accelerate the corrosion rate of the equipment. Therefore, the phosphorus content should not exceed 0.05%. If the content is less than 0.01%, the increase in thermal conductivity achieved by phosphorus is insufficient, and the thermal conductivity of the contact layer 20 is not significantly improved.

[0020] Example 1

[0021] In the material of the contact layer, the percentage content of nickel is 1.5% to 2.5%, the percentage content of tin is 1.5% to 2.0%, the percentage content of phosphorus is 0.02% to 0.04%, the percentage content of bismuth is 0.01% to 0.06%, and the rest is copper.

[0022] Example 2

[0023] In the material of the contact layer, the percentage content of nickel is 0.9% to 1.2%, the percentage content of tin is 7% to 9.0%, the percentage content of phosphorus is 0.01% to 0.03%, the percentage content of bismuth is 0.03% to 0.08%, and the rest is copper.

[0024] Example 3

[0025] In the material of the contact layer, the percentage content of nickel is 0.1% to 0.3%, the percentage content of tin is 6% to 7%, the percentage content of phosphorus is 0.11% to 0.17%, the percentage content of bismuth is 0.04% to 0.07%, and the rest is copper.

[0026] For the above-mentioned embodiment, friction performance, tensile strength, fatigue strength, and compression deformation, i.e., structural strength, were tested using a testing machine, and the test results are as follows.

[0027] Table 1 Friction performance test results

[0028]

[0029] Table 2 Tensile strength test results

[0030]

[0031] Table 3 Fatigue strength test results

[0032]

[0033]

[0034] Table 4 Compression deformation test results

[0035]

[0036] Through the above tests, it can be concluded that the functions of the material of the present application, such as friction performance, tensile strength, fatigue strength, compression deformation, and structural strength, all meet the requirements.

[0037] Compared to the prior art, the valve plate for an internal gear pump provided by the present invention improves its lifespan, corrosion resistance, wear resistance, and strength by providing the contact layer. Specifically, the alloy powder of copper, tin, nickel, phosphorus, and bismuth is formed by sintering and rolling at a specific temperature. The nickel content is 0.9% to 9.0%, the tin content is 1.5% to 11%, the phosphorus content is 0.01% to 0.05%, the bismuth content is 0.005% to 0.08%, and the remainder is copper. The nickel improves the corrosion resistance of the contact layer, increases the material's hardness, and improves its heat resistance. The tin forms a solid solution in the copper matrix, thereby strengthening the contact layer's structural strength and also enhancing its wear resistance. The phosphorus improves the contact layer's strength, hardness, thermal conductivity, and wear resistance. The bismuth enhances the alloy's strength and hardness, maintaining good dimensional stability in high-temperature environments. At the same time, during sintering, the porosity is limited to 0.1% to 0.3%, thereby ensuring the various properties of the distribution plate, such as strength and toughness, hardness and wear resistance, and thermal conductivity, while also ensuring the lubrication performance of the distribution plate.

[0038] The above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements or improvements within the spirit of the present invention are included in the scope of the claims of the present invention.

Claims

1. A valve plate for an internal gear pump, characterized in that: The distribution disc for the internal gear pump includes a substrate layer and a contact layer sintered on the substrate layer. The contact layer is sintered and rolled from alloy powder of copper, tin, nickel, phosphorus, and bismuth. The porosity of the contact layer is 0.1% to 0.3%, the percentage content of nickel is 0.9% to 9.0%, the percentage content of tin is 1.5% to 11%, the percentage content of phosphorus is 0.01% to 0.05%, the percentage content of bismuth is 0.005% to 0.08%, and the remainder is copper.

2. The valve plate for an internal gear pump according to claim 1, wherein: The substrate layer 10 can be made of steel, copper, or a copper alloy.

3. The valve plate for an internal gear pump according to claim 1, wherein: In the material of the contact layer, the percentage content of nickel is 1.5% to 2.5%, the percentage content of tin is 1.5% to 2.0%, the percentage content of phosphorus is 0.02% to 0.04%, the percentage content of bismuth is 0.01% to 0.06%, and the rest is copper.

4. The valve plate for an internal gear pump according to claim 1, wherein: In the material of the contact layer, the percentage content of nickel is 0.9% to 1.2%, the percentage content of tin is 7% to 9.0%, the percentage content of phosphorus is 0.01% to 0.03%, the percentage content of bismuth is 0.03% to 0.08%, and the rest is copper.

5. The valve plate for an internal gear pump according to claim 1, wherein: In the material of the contact layer, the percentage content of nickel is 0.1% to 0.3%, the percentage content of tin is 6% to 7%, the percentage content of phosphorus is 0.11% to 0.17%, the percentage content of bismuth is 0.04% to 0.07%, and the rest is copper.

6. The valve plate for an internal gear pump according to claim 1, wherein: In the material of the contact layer, the percentage content of nickel is 7.5% to 9.0%, the percentage content of tin is 6.0% to 7.5%, the percentage content of phosphorus is 0.25% to 0.43%, the percentage content of bismuth is 0.06% to 0.08%, and the rest is copper.

7. The valve plate for an internal gear pump according to claim 1, wherein: In the material of the contact layer, the percentage content of nickel is 0.05% to 0.2%, the percentage content of tin is 9% to 11%, the percentage content of phosphorus is 0.11% to 0.17%, the percentage content of bismuth is 0.04% to 0.07%, and the rest is copper.

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