Piston internal lubrication structure

Abstract

The utility model relates to a piston internal lubricating structure, at least one flow guide channel is formed between the piston internal near piston inner check pin seat and piston head inner cooling oil channel, one end of flow guide channel communicates with inner cooling oil channel, and another end communicates with piston pin hole inner chamber, the utility model solves the lubricating problem between connecting rod small head and piston pin, through setting up the cooling machine oil flow guide channel in the piston internal, directly lubricating piston pin, lubricating oil will along the surface of piston pin extend respectively to piston pin hole and connecting rod small head, and then lubricates the internal surface of piston pin hole and connecting rod small head hole, can form a whole process lubricating effect.

Description

Technical Field

[0001] This utility model relates to the field of piston lubrication technology, specifically to an internal lubrication structure for a piston. Background Technology

[0002] Steel pistons offer significant advantages in reliability and heat resistance, and have a long service life. However, with increased burst pressure, the pressure on the steel piston pin bore is much greater than that on the original aluminum piston, currently reaching up to 150 MPa. Such high pressure may not pose a challenge to the fatigue strength of the steel piston pin bore, but it can easily damage the lubricating oil film between the piston pin and the piston pin bore. During the entire engine operation, the piston pin bore and piston pin are in a state of insufficient lubrication due to a lack of lubricating oil, and the lubricating oil cannot directly enter the piston pin and piston pin bore to provide direct and effective lubrication. This exacerbates the wear between the piston pin and piston pin bore, easily leading to piston pin engagement failure and causing overall engine malfunction.

[0003] To prevent seizing and wear in the pin hole due to insufficient lubrication, some lubrication measures have been adopted in past applications. Common lubrication methods for pin holes and piston pins include lubrication groove lubrication, piston internal cavity drain hole lubrication, and piston internal cavity drain hole plus connecting rod small end lubrication hole lubrication.

[0004] Among them, the lubrication groove method involves setting a lubrication groove at the pin hole, which has a certain storage function for lubricating oil and provides a certain lubrication effect for the piston pin hole, thus improving the wear of the pin hole to a certain extent. However, the drawback of this structural scheme is that the lubricating oil does not have a fixed source, and it is difficult to reach the lubrication groove at the pin hole through splashing. Initially, the oil coating on the piston pin will have a certain effect, but as the engine runs for a long time, the supply of lubricating oil will be insufficient, reducing the lubrication effect.

[0005] The piston internal cavity oil drain hole method refers to a method where the piston internal cavity has an oil drain hole connected to the internal cooling oil passage. The connecting rod small end does not have a corresponding lubrication through-hole. This method relies on the oil drained from the piston internal cavity falling onto the connecting rod small end and splashing through the gap between the connecting rod small end and the piston inner end for lubrication. This method provides poor lubrication for the piston pin bore and connecting rod small end bore because lubricating oil has difficulty entering these areas. Practical experience has shown that even with this type of internal oil drain hole, piston pin bore wear still frequently occurs during engine bench tests, and it does not solve the problems encountered in practical applications.

[0006] The method of adding an oil drain hole in the piston cavity and a lubrication hole on the connecting rod small end involves machining an oil drain hole in the piston cavity that connects to the internal cooling oil passage, and machining a lubrication through-hole on the connecting rod small end at a certain angle to the oil drain hole in the piston's internal cooling oil passage. During piston operation, at a certain moment, the cooling oil from the oil drain hole in the internal cooling oil passage can enter the through-hole in the connecting rod small end, thus directly lubricating the piston pin and the connecting rod small end. This forms a lubricating oil film between the piston pin and the connecting rod small end, preventing wear and tear between the connecting rod small end and the piston pin. However, the lubricating oil can only lubricate the connecting rod small end hole at a certain moment and cannot provide lubrication throughout the entire process. Although this technical solution has a relatively obvious lubrication effect on the connecting rod small end and piston pin, the oil from the oil drain hole in the internal cooling oil passage is difficult to reach the pin hole area. Therefore, this solution does not have a significant lubrication effect on the piston pin hole. Practice has proven that it cannot solve the problem of pin hole wear in practical applications.

[0007] The above lubrication methods can provide some lubrication, but the lubrication effect is not good. After the piston has been working for a long time, the piston pin hole is prone to wear, which leads to piston pin engagement failure and causes the whole machine to malfunction. With the increasing level of engine enhancement, the lubrication effect of these lubrication methods can no longer meet the requirements in engine bench testing and the aftermarket. Utility Model Content

[0008] To address the shortcomings of existing technologies, this utility model provides a piston lubrication device and manufacturing method. By strengthening the lubrication angle between the piston pin hole and the piston pin, and between the piston connecting rod small end and the piston pin, it can effectively solve the problem of pin hole engagement failure caused by insufficient lubrication.

[0009] This utility model is achieved through the following technical solution: A piston internal lubrication structure is provided, wherein at least one guide channel is formed inside the piston between the internal cooling oil passage near the piston inner retaining pin seat and the piston head, one end of the guide channel is connected to the internal cooling oil passage, and the other end is connected to the piston pin hole cavity.

[0010] This solution utilizes a guide channel to connect the internal cooling oil passage and the inner wall of the piston pin hole, thereby guiding the cooling oil in the internal cooling oil passage. Under the guidance of the guide channel, the cooling oil lubricates the piston pin hole, piston pin, and piston connecting rod small end.

[0011] Furthermore, there are two flow channels, located at the piston pin seat on one side of the piston or at the two piston pin seats on both sides of the piston.

[0012] There are two flow channels, which can be set at the piston pin seat on one side or at the two piston pin seats on both sides, depending on the actual situation.

[0013] Preferably, each guide channel has an internal thread at one end near the internal cooling oil passage, and the guide channel is connected to a hollow bolt with open ends by a thread. The hollow inner cavity of the hollow bolt near the piston pin hole has an N-sided cross section, and N≥3.

[0014] By connecting a hollow bolt with an internal thread in the flow channel, the cavity of the hollow bolt is used for flow guidance, so that the oil in the internal cooling oil passage can be introduced into the pin hole for lubrication. The hollow inner cavity at the end of the hollow bolt is set as a polygon, which can be easily rotated with a polygonal wrench for easy disassembly and assembly.

[0015] Furthermore, the hollow bolt includes a threaded section and a smooth section. The threaded section is provided with an external thread that is threaded to the internal thread of the guide channel, and the diameter of the smooth section is smaller than the inner diameter of the guide channel.

[0016] The threaded section of the hollow bolt is used to connect and fix it to the internal thread of the guide channel. The diameter of its smooth section is smaller than the inner diameter of the guide channel, which makes it convenient to disassemble and replace it from inside the guide channel.

[0017] Preferably, the end of the smooth section of the hollow bolt is located inside the guide channel.

[0018] The smooth section of the hollow bolt is set inside the flow channel, and its end does not extend outside the flow channel, which can avoid interference between its end and the piston pin and ensure the stability of piston operation.

[0019] Preferably, the hollow bolt is either a hollow steel bolt or a hollow copper bolt.

[0020] Hollow bolts made of steel and copper are high in strength and not easily worn or rusted, ensuring long-term flow guidance and reducing maintenance costs.

[0021] Furthermore, the inner circumferential wall of the piston pin hole of the piston forms an annular oil reservoir that is connected to the outlet of the guide channel.

[0022] By adding an annular oil reservoir, under pressure, the cooling oil in the internal cooling oil passage enters the annular oil reservoir through the guide hole. Under pressure, the cooling oil will fill the entire annular oil reservoir. Because there is a gap between the piston pin hole and the piston pin, the cooling oil will spread to both sides after it is filled, flowing evenly and continuously into the surface of the piston pin hole and the piston pin, thus achieving lubrication throughout the process.

[0023] The beneficial effects of this utility model are: This invention's lubrication structure eliminates the need for a separate lubrication hole at the connecting rod small end. By adding a guide channel within the piston cavity and using a hollow bolt to guide the cooling oil, the piston pin is directly lubricated. Under the pressure of the cooling oil, the lubricating oil extends along the surface of the piston pin towards the piston pin bore and the connecting rod small end, thus lubricating the internal surfaces of both. Throughout the piston's operation, a continuous lubrication process is achieved, ensuring an uninterrupted lubricating oil film on the piston pin bore surface throughout the engine's entire service life, preventing pin wear, seizing, and locking.

[0024] The hollow bolt is embedded in the piston pin seat, with its end positioned within the guide channel to avoid interference with the small end of the connecting rod. Furthermore, analytical tests have verified that it does not affect the strength of the piston pin bore. The addition of an annular oil reservoir allows the cooling oil to fill the entire reservoir under pressure. Because there is a gap between the piston pin bore and the piston pin, the cooling oil, once filled, spreads to both sides, flowing evenly and continuously into the surfaces of the piston pin bore and piston pin, achieving lubrication throughout the entire process.

[0025] The lubrication structure of this invention provides significant lubrication for the piston pin bore and piston pin surface. This lubrication structure can be applied to steel pistons, aluminum piston pin bores, and aluminum piston pin bores with copper bushings. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of this utility model.

[0027] Figure 2 This is a structural schematic diagram of Embodiment 2 of the present invention.

[0028] Figure 3 for Figure 2 A cross-sectional view of a hollow bolt.

[0029] Figure 4 for Figure 2 A schematic diagram of the structure of the central guide channel.

[0030] Figure 5 This is a schematic diagram showing the location of the guide channel in Embodiment 2 of this utility model.

[0031] Figure 6 This is a structural schematic diagram of Embodiment 3 of the present invention.

[0032] Figure 7 for Figure 6 Side view.

[0033] As shown in the figure: 1. Guide channel, 2. Internal cooling oil passage, 3. Piston pin hole, 4. Hollow bolt, 41. Threaded section, 42. Smooth section, 5. Annular oil reservoir, 6. Oil inlet. Detailed Implementation

[0034] To clearly illustrate the technical features of this solution, the following detailed implementation method will be used to explain the solution.

[0035] Example 1: like Figure 1 As shown, a piston internal lubrication structure is provided, wherein at least one guide channel 1 is formed inside the piston between the internal cooling oil passage 2 near the piston inner retaining pin seat and the piston head. One end of the guide channel 1 is connected to the internal cooling oil passage 2, and the other end is connected to the piston pin hole cavity.

[0036] In this embodiment, there are two flow channels 1, which are located at the piston pin seat on one side of the piston and are symmetrically arranged about the piston's central axis.

[0037] like Figure 1 As shown, the guide channel 1 guides the cooling oil in the internal cooling oil passage 2. Under the guidance of the two guide channels 1, the cooling oil lubricates the piston pin hole, piston pin, and piston connecting rod small end.

[0038] Example 2: Based on Example 1, each guide channel 1 is provided with an internal thread at one end near the internal cooling oil passage 2, and hollow bolts 4 with open ends are connected to the guide channel 1 by threads. The hollow bolts 4 are either hollow steel bolts or hollow copper bolts, and steel hollow bolts can be selected.

[0039] The hollow inner cavity of the hollow bolt 4 near the piston pin hole has an N-sided cross-section, where N ≥ 3. In this embodiment, the cross-section of the hollow inner cavity is a regular hexagon.

[0040] The hollow bolt 4 includes a threaded section 41 and a smooth section 42. The threaded section 41 has an external thread that connects to the internal thread of the guide channel 1. The diameter of the smooth section 42 is smaller than the inner diameter of the guide channel 1. Generally, the diameter difference between the two should be greater than 1 mm to facilitate installation and removal. The end of the smooth section 42 of the hollow bolt 4 is located inside the guide channel 1. After installation, the end of the hollow bolt 4 near the pin hole should maintain a certain distance C from the outer diameter of the piston pin hole. Figure 2 As shown, it should generally be greater than 2mm to prevent interference with the piston pin.

[0041] like Figure 4As shown, to mate with the hollow bolt 4, the guide channel is divided into two sections: a channel with a diameter of ΦA and a hole with a diameter of ΦB, where ΦA is larger than ΦB. The channel with a diameter of ΦB has internal threads that mate with the threaded section 41 of the hollow bolt 4. The channel with a diameter of ΦA mates with the smooth section of the hollow bolt 4. To ensure the length of the threaded hole, the internal thread can be machined from a solid material, such as a regular cylindrical shape. High-temperature resistant sealant is applied to the hollow bolt 4 before installation to prevent loosening.

[0042] When the engine is running, the cooling oil first reaches the piston's internal cooling oil passage 2 through the cooling nozzles that supply cooling oil to the piston. Under pressure, the cooling oil flows within the internal cooling oil passage 2, then flows through the two hollow bolts 4 to the piston pin surface. Under pressure, the cooling oil spreads to the piston pin bore surface and the connecting rod small end bore surface, forming a lubricating film on the piston pin surface, thus providing lubrication. The main function of the hollow bolts 4 is to guide the cooling oil from the internal cooling oil passage 2, allowing the hollow bolts 4 to be as close as possible to the piston pin surface without interfering with it. Under pressure, the oil directly reaches the piston pin surface. As long as the engine is running, the cooling oil will continuously reach the piston pin surface, providing lubrication throughout the entire process. This device lubricates not only the piston pin bore surface but also the connecting rod small end bore surface. Hollow bolt 4 not only serves to guide the flow of cooling oil, but also acts as a return hole for the internal cooling oil passage. Arranging three identical hollow bolts in the piston cavity can ensure sufficient lubrication and increase the return oil effect, eliminating the need to machine the return hole for the internal cooling oil passage on the piston.

[0043] like Figure 5 As shown, considering the cooling effect of the piston head, the guide channel 1 and the hollow bolt 4 are installed on the side away from the oil inlet.

[0044] Example 3: like Figure 6 and Figure 7 As shown, the inner circumferential wall of the piston pin hole of the piston forms an annular oil reservoir 5 that is connected to the outlet of the guide channel 1.

[0045] Cooling oil enters the internal cooling oil passage 2 through the cooling nozzle. Under pressure, it flows within the internal cooling oil passage 2 and enters the annular oil outlet groove 5 in the piston pin hole through the guide channel 1. Under pressure, the cooling oil fills the entire annular oil reservoir 5. Because there is a gap between the piston pin hole and the piston pin, the cooling oil spreads to both sides after filling, flowing evenly and continuously into the surfaces of the piston pin hole and piston pin, achieving lubrication throughout the entire process. This lubrication structure provides significant lubrication to the piston pin hole and piston pin surface. This lubrication structure can be applied to steel pistons, aluminum piston pin holes, and aluminum piston pin holes with copper bushings.

[0046] Of course, the above description is not limited to the examples above. Technical features not described in this utility model can be implemented by or using existing technology, and will not be repeated here. The above embodiments and drawings are only used to illustrate the technical solution of this utility model and are not intended to limit this utility model. This utility model has been described in detail with reference to preferred embodiments. Those skilled in the art should understand that any changes, modifications, additions or substitutions made by those skilled in the art within the scope of this utility model do not depart from the spirit of this utility model and should also fall within the protection scope of the claims of this utility model.

Claims

1. A piston internal lubrication structure, characterized in that: Inside the piston, at least one flow channel is formed between the internal cooling oil passage near the piston inner retaining pin seat and the piston head. One end of the flow channel is connected to the internal cooling oil passage, and the other end is connected to the inner cavity of the piston pin hole.

2. The piston internal lubrication structure according to claim 1, characterized in that: There are two flow channels, located at the piston pin seat on one side of the piston or at the two piston pin seats on both sides of the piston.

3. The piston internal lubrication structure according to claim 2, characterized in that: Each guide channel has an internal thread at one end near the internal cooling oil passage, and hollow bolts with open ends are connected to the guide channel through the thread. The cross-section of the hollow inner cavity of the hollow bolt near the piston pin hole is N-sided, and N≥3.

4. The piston internal lubrication structure according to claim 3, characterized in that: The hollow bolt consists of a threaded section and a smooth section. The threaded section has an external thread that connects to the internal thread of the guide channel, while the diameter of the smooth section is smaller than the inner diameter of the guide channel.

5. The piston internal lubrication structure according to claim 4, characterized in that: The end of the smooth section of the hollow bolt is located inside the flow channel.

6. The piston internal lubrication structure according to claim 3, 4, or 5, characterized in that: Hollow bolts are a type of hollow steel bolt or hollow copper bolt.

7. The piston internal lubrication structure according to claim 1, characterized in that: The inner circumferential wall of the piston pin hole of the piston forms an annular oil reservoir that is connected to the outlet of the guide channel.

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