A new type of friction pair plunger pump

Abstract

This utility model relates to the field of hydraulic technology and discloses a novel friction pair piston pump, including a friction pair disposed in the piston pump. The friction pair includes a first friction element and a second friction element, which are made of the same material. A wear-resistant coating is provided on the surface of the first friction element and / or the surface of the second friction element. The wear-resistant coating is used to reduce adhesive wear between the first and second friction elements, and the friction coefficient of the wear-resistant coating is lower than that of the first friction element. In this design, the two structural expansion coefficients of the friction pair are consistent, which can avoid the decrease in the fitting accuracy of the friction pair due to temperature, making it suitable for extreme high and low temperature environments. The wear-resistant coating prevents direct contact between the two structural surfaces of the friction pair, avoiding the adhesive wear problem caused by the use of the same material in traditional friction pair structures. It can be used in hydraulic systems with extreme operating temperatures, such as deep-sea hydraulic systems and field hydraulic systems, thus having a wider range of applications.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic technology, specifically to a novel friction pair piston pump. Background Technology

[0002] There are multiple friction pairs in the components of a piston pump, among which the friction pair between the cylinder block and the piston is a critical one, which is crucial to the performance and lifespan of the piston pump. Currently, the friction pair materials of the cylinder block and piston mainly adopt the following methods:

[0003] 1. The cylinder block is made of pure copper alloy, and the plunger is made of alloy steel. Copper alloy has a low coefficient of friction, resulting in good friction performance of the friction pair, making it suitable for low-speed and high-speed environments. It also has high strength and good toughness, making it suitable for medium- and high-pressure environments. However, the two friction pair materials have different coefficients of thermal expansion, which limits its use under extreme temperatures while ensuring pump volumetric efficiency.

[0004] 2. The cylinder block is made of alloy steel with a copper sleeve inlaid in the plunger bore. The plunger is also made of alloy steel. Copper alloy has a low coefficient of friction, resulting in good friction performance of the friction pair, suitable for low-speed and high-speed environments; it also has high strength and good toughness, suitable for medium- and high-pressure environments; the copper sleeve can be replaced individually after wear, eliminating the need to replace the entire cylinder block, thus reducing maintenance costs. However, the manufacturing process is complex and costly; the copper alloy layer is prone to deformation and damage under high-pressure impact; the thermal expansion coefficients of copper alloy and alloy steel are different, which may generate thermal stress under high-temperature conditions, affecting the fitting accuracy and thus affecting pump performance.

[0005] 3. The cylinder block is made of alloy steel with a copper layer cast into the plunger bore. The plunger is also made of alloy steel. Copper alloy has a low coefficient of friction, resulting in good friction performance of the friction pair, making it suitable for low-speed and high-speed environments. It also has high strength and good toughness, making it suitable for medium- and high-pressure environments. However, the manufacturing process is complex and costly. The copper alloy layer is prone to deformation and damage under high-pressure impact. The thermal expansion coefficients of copper alloy and alloy steel are different, which may generate thermal stress under high-temperature conditions, affecting the fitting accuracy and thus the pump performance.

[0006] 4. The cylinder block is made of ductile iron, and the plunger is made of alloy steel. Ductile iron has good wear resistance, especially under high load and impact conditions. However, ductile iron has high strength and is used in medium and high pressure environments, but its friction pair performance is slightly lower than that of copper alloys; it is only suitable for low-speed environments.

[0007] In summary, to ensure good friction performance, the cylinder block and plunger friction pair are currently made of different materials. However, due to the different materials used, the cylinder block and plunger friction pair will experience restricted expansion and uneven contraction under extreme conditions, generating thermal stress, affecting the fitting accuracy of the cylinder block and plunger friction pair, and ultimately affecting the pump performance. Utility Model Content

[0008] The present invention aims to provide a novel friction pair piston pump to solve the problem that the friction pair of the cylinder block and piston cannot adapt to extreme high and low temperature environments.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: a novel friction pair plunger pump, comprising a friction pair disposed in the plunger pump, the friction pair comprising a first friction element and a second friction element, the first friction element and the second friction element being made of the same material, the surface of the first friction element and / or the surface of the second friction element being provided with a wear-resistant coating, the wear-resistant coating being used to reduce adhesive wear between the first friction element and the second friction element, the friction coefficient of the wear-resistant coating being less than the friction coefficient of the first friction element.

[0010] The principle of this solution is as follows: After the plunger pump starts, the two friction components in the friction pair move relative to each other. The wear-resistant coatings of the friction components rub against each other or the surfaces of the friction components rub against the wear-resistant coatings, thus avoiding direct contact between the surfaces of the two friction components and maintaining good lubricity and wear resistance of the friction pair.

[0011] Advantages of this solution: The two structures of the friction pair have the same coefficient of thermal expansion, which can avoid the temperature-induced changes in the fitting accuracy of the friction pair, making it suitable for extreme high and low temperature environments; the wear-resistant coating prevents direct contact between the two structural surfaces of the friction pair, avoiding the adhesive wear problem caused by the use of the same material in traditional friction pair structures; it can be used in hydraulic systems with extreme operating temperatures, such as deep-sea hydraulic systems and field hydraulic systems, making it more adaptable.

[0012] Preferably, both the first and second friction components are made of stainless steel, and the wear-resistant coating is a DLC coating. This design, through its stainless steel + DLC coating structure, maintains good lubrication and wear resistance within a temperature range of -60 to 200 degrees Celsius. In hydraulic systems using traditional plunger pumps, the performance of the plunger pump significantly decreases after water ingress, and components may even rust and become completely unusable. However, this design, with its stainless steel and DLC coating, allows for near-normal operation even when water enters the hydraulic system. Even when the system medium is entirely replaced with water, it can still maintain 70% of the system pressure. Furthermore, this design ensures a certain level of performance for the plunger pump when using low-viscosity media.

[0013] Preferably, the wear-resistant coating is located on the friction contact surface of the first friction element and / or the friction contact surface of the second friction element. This saves costs and simplifies the manufacturing process.

[0014] Preferably, the friction pairs include: a cylinder block and plunger friction pair, a cylinder block and distributor plate friction pair, a slipper and swashplate friction pair, and a slipper and return plate friction pair.

[0015] Preferably, the wear-resistant coating is applied to the surface of the plunger, the distribution plate, the swashplate, and the return plate.

[0016] Preferably, the wear-resistant coating thickness of the friction contact surface of the friction element in the friction pair is greater than the wear-resistant coating thickness of the corresponding non-friction contact surface of the friction element in the friction pair. Friction contact surfaces are more prone to wear, and increasing the thickness improves the wear resistance and service life of the structure.

[0017] Preferably, the shape of the wear-resistant coating matches the shape of the friction contact surface of the first friction element, and the shape of the wear-resistant coating matches the shape of the friction contact surface of the second friction element.

[0018] Preferably, the surface of the wear-resistant coating is a smooth plane, which reduces the motion resistance of the two friction components, slows down the wear rate of the components, and extends the service life of the structure. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the cylinder and plunger in an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of the plunger structure in an embodiment of the present invention. Detailed Implementation

[0021] The following detailed description illustrates the specific implementation method:

[0022] The reference numerals in the accompanying drawings include: cylinder 1, plunger 2, and wear-resistant coating 3.

[0023] Example

[0024] A novel friction pair plunger pump includes a friction pair disposed in the plunger pump. The friction pair includes a first friction element and a second friction element, which are made of the same material. The surface of the first friction element and / or the surface of the second friction element are provided with a wear-resistant coating 3. The wear-resistant coating 3 is used to reduce adhesive wear between the first friction element and the second friction element. The wear-resistant coating 3 avoids direct contact between the two structural surfaces of the friction pair, thus avoiding the adhesive wear problem caused by the use of the same material in traditional friction pair structures.

[0025] In this scheme, the friction coefficient of the wear-resistant coating 3 is less than that of the first friction component. That is, when the friction pair mechanism moves, the wear-resistant coating 3 will be damaged first, thus extending the service life of the friction component as much as possible.

[0026] The shape of the wear-resistant coating 3 matches the shape of the friction contact surface of the first friction component, and the shape of the wear-resistant coating 3 matches the shape of the friction contact surface of the second friction component.

[0027] In this embodiment, the thickness of the wear-resistant coating 3 on the friction contact surface of the friction element in the friction pair is greater than the thickness of the wear-resistant coating 3 on the corresponding non-friction contact surface of the friction element in the friction pair. The friction contact surface is more prone to wear, and increasing the thickness improves the wear resistance and service life of the structure.

[0028] In this design, both the first and second friction components are made of stainless steel, specifically high-strength stainless steel, which has high strength, good toughness, and good corrosion resistance, resulting in a longer service life and lower maintenance costs in hydraulic systems.

[0029] Among them, wear-resistant coating 3 is a DLC coating. DLC coating (Diamond-Like Carbon) is an amorphous thin film material composed of carbon atoms, which combines the hardness of diamond and the lubricity of graphite to achieve the functions of reducing the coefficient of friction and wear resistance. Since the parts of traditional plunger pumps are made of carbon steel and copper alloy as friction pairs, when the medium is hydraulic oil, an oil film can be successfully established and the coefficient of friction is relatively low. However, when water enters the system and water is used as the medium, the carbon steel and copper alloy cannot establish a water film of normal thickness, which will accelerate the wear of parts and even cause material transfer between friction pairs, damaging the friction pair parts and reducing the pump life. Moreover, carbon steel and copper alloy will rust if they are soaked in water for a long time, which will also reduce the pump life. Therefore, in hydraulic systems using traditional piston pumps, the performance of the pumps drops significantly after water enters the system, and components may even rust and become completely unusable. This solution, using stainless steel and DLC coating, allows the pump to function almost normally even when water enters the hydraulic system. Even when the system medium is completely replaced with water, it can still maintain 70% of the system pressure. This solution also ensures a certain level of performance when using low-viscosity media. The stainless steel + DLC coating structure in this solution maintains good lubrication and wear resistance within a temperature range of -60 to 200 degrees Celsius.

[0030] This solution specifically utilizes the WYKJ-08 high and low temperature test chamber to conduct durability tests on the pump. Under extreme ambient temperatures of -60℃ and 200℃, the plunger pump of this application was run under load for several hundred hours. During the process, the motor current remained stable. After the test, disassembly and inspection revealed normal wear on each friction pair. No peeling of the DLC coating was observed, and the surfaces of the mating friction pair parts were smooth without material transfer or severe wear marks. This demonstrates that the stainless steel + DLC coating structure can maintain good lubrication and wear resistance for a long time in high and low temperature environments.

[0031] The friction pairs in the plunger pump include the friction pair between cylinder block 1 and plunger 2, the friction pair between cylinder block 1 and distributor plate, the friction pair between slipper and swashplate, and the friction pair between slipper and return plate. All of these structures utilize the aforementioned high-strength stainless steel and DLC coating. The two structures of the friction pair are made of the same material, with identical coefficients of thermal expansion, which avoids temperature-induced changes in the fit precision of the friction pair and makes it suitable for extreme high and low temperature environments. The wear-resistant coating 3 ensures good lubrication and wear resistance for the friction pair. The specific details of the friction pair between cylinder block 1 and plunger 2 are as follows... Figure 1 As shown.

[0032] The wear-resistant coating 3 is located on the friction contact surface of the first friction component and / or the friction contact surface of the second friction component. This saves costs and simplifies the manufacturing process. In this solution, a DLC coating is applied to the surface of one of the friction components, specifically on the surfaces of the plunger 2, the distribution plate, the swash plate, and the return plate in the plunger pump friction pair. This solution specifically employs methods such as physical vapor deposition (PVD), chemical vapor deposition (CVD), or ion plating to apply the DLC coating to the friction component surfaces.

[0033] like Figure 1 and Figure 2 As shown, in this embodiment, a DLC coating is provided on the outer surface of the plunger 2. When the plunger pump starts, the plunger 2 reciprocates in the plunger cavity of the cylinder 1. The DLC coating on the surface of the plunger 2 rubs against the inner wall of the plunger cavity, avoiding the adhesive wear problem caused by direct contact friction between the plunger 2 and the cylinder 1, while maintaining good lubrication and wear resistance of the friction pair. In this solution, the cylinder 1 and the plunger pump are manufactured using an integrated process, resulting in better sealing performance.

[0034] Among them, the surface of the wear-resistant coating 3 is a smooth plane, which reduces the motion resistance of the two friction parts, slows down the wear rate of the components, and extends the service life of the structure.

[0035] The above descriptions are merely embodiments of this utility model, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solution of this utility model. In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances. The scope of protection claimed in this application shall be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A novel friction pair plunger pump, comprising a friction pair disposed in the plunger pump, the friction pair comprising a first friction element and a second friction element, characterized in that: The first friction element and the second friction element are made of the same material. The surface of the first friction element and / or the surface of the second friction element are provided with a wear-resistant coating. The wear-resistant coating is used to reduce adhesive wear between the first friction element and the second friction element. The coefficient of friction of the wear-resistant coating is less than the coefficient of friction of the first friction element.

2. The novel friction pair plunger pump according to claim 1, characterized in that: Both the first and second friction components are made of stainless steel, and the wear-resistant coating is a DLC coating.

3. The novel friction pair plunger pump according to claim 1, characterized in that: The wear-resistant coating is located on the friction contact surface of the first friction element and / or the friction contact surface of the second friction element.

4. A novel friction pair plunger pump according to claim 1, characterized in that: The friction pairs include: cylinder block and plunger friction pair, cylinder block and distributor plate friction pair, slipper and swashplate friction pair, and slipper and return plate friction pair.

5. A novel friction pair plunger pump according to claim 4, characterized in that: The wear-resistant coating is applied to the surfaces of the plunger, distribution plate, swash plate, and return plate.

6. A novel friction pair plunger pump according to claim 1, characterized in that: The wear-resistant coating thickness of the friction contact surface of the friction element in the friction pair is greater than the wear-resistant coating thickness of the non-friction contact surface of the corresponding friction element in the friction pair.

7. A novel friction pair plunger pump according to claim 1, characterized in that: The shape of the wear-resistant coating matches the shape of the friction contact surface of the first friction element, and the shape of the wear-resistant coating matches the shape of the friction contact surface of the second friction element.

8. A novel friction pair plunger pump according to claim 1, characterized in that: The surface of the wear-resistant coating is a smooth plane.

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