CN102278225A - A low-friction axial unequal angle platform honing cylinder liner - Google Patents

Abstract

The invention provides a low-friction axial unequal-angle platform honing cylinder jacket, belonging to the design field of cylinder jackets. The low-friction axial unequal-angle platform honing cylinder jacket is characterized in that the central part of the inner wall of the cylinder jacket is provided with a slotted reticulate pattern with an included angle alpha, wherein alpha is a reticulate-pattern included angle of a honing reticulate pattern at the central part of the cylinder jacket in the direction of a central axial line of the cylinder jacket, and is larger than 160 degrees and smaller than 180 degrees; and two end parts of the inner wall of the cylinder jacket are provided with slotted reticulate patterns with an included angle beta, wherein beta is a reticulate-pattern included angle of the honing reticulate pattern at two end parts of the cylinder jacket in the direction of the central axial line of the cylinder jacket, and is larger than 0 degree and smaller than 20 degrees. The low-friction axial unequal-angle platform honing cylinder jacket disclosed by the invention can reduce the friction coefficient of the cylinder jacket.

Description

A low-friction axial unequal angle platform honing cylinder liner

Technical field:

The invention relates to a low-friction axial unequal-angle platform honing cylinder liner, which belongs to the field of cylinder liner design.

Background technique:

In the engine system, the friction loss consumed on the two friction pairs of piston/cylinder liner and piston ring/cylinder liner accounts for about 44% of the overall friction loss. Therefore, for a long time, people have never stopped researching on engine cylinder liners to reduce friction and increase lubrication. In addition, in order to reduce environmental pollution, the National Environmental Protection Agency enforced the China Light Vehicle III and IV emission standards on January 1, 2007, making it urgent to further improve the tribological properties of engine cylinder liners.

Platform honing anilox technology is a surface processing technology that has been used since the middle of last century. The platform honing anilox process has become an indispensable process technology for the machining of precision coupling parts such as engine cylinder liners, cylinder bores and important hydraulic cylinders in construction machinery. General attention. The platform texture is processed on the inner wall of the cylinder liner, which is beneficial to shorten the running-in period of the engine. During operation, a certain amount of lubricating oil can be stored in the texture groove to provide good lubrication conditions for its normal operation. So far, the included angle of the honing texture on the inner wall of the cylinder liner in the direction of the central axis of the cylinder liner is mostly an obtuse angle, and the common one is 135±15°. In order to increase the return flow rate of lubricating oil in the honing pattern, there are also patents designed to be 30~85°. In these designs, the texture is uniformly distributed across the inner wall of the cylinder liner. The processing method is that the honing machine drives the honing head to perform rotary motion and reciprocating motion in the inner hole of the cylinder liner at the same time, and the set value of the mesh angle in the direction of the central axis of the cylinder liner is realized by controlling the magnitude of the two speeds.

Invention content:

The object of the present invention is to provide a low-friction axial unequal angle platform honing cylinder liner, which can further reduce the friction coefficient of the cylinder liner.

During the working process of the engine, the piston and piston ring reciprocate along the central axis of the cylinder liner, and the speed experienced by the inner wall of the cylinder liner changes sinusoidally. That is, the end portions of the cylinder liner experience smaller velocities, while the middle portion of the cylinder liner experiences greater velocities. The groove-shaped stripes on the inner wall of the cylinder liner not only play the role of storing lubricating oil, but at the same time, when the speed is high, the existence of the grooves will generate fluid dynamic pressure, thereby reducing the friction between the cylinder liner and the piston or piston ring. direct contact, thereby reducing their friction. The angle between the groove and the direction of velocity has a direct impact on the ability of the oil film to generate hydrodynamic pressure. When the velocity is large, the grooves perpendicular to the velocity direction are more likely to make the oil film generate hydrodynamic pressure. When the speed is low, it mainly relies on the lubricating oil in the groove to compensate to the contact surface to reduce friction. At this time, the groove parallel to the speed direction can play a better role. The design of the texture for different positions in the direction of the central axis of the cylinder liner is helpful to further improve the tribological performance of the cylinder liner, but this design has not been reported yet.

The present invention is realized through the following technical solutions: by controlling the size of the rotating and reciprocating motion speed of the honing head in the inner hole of the cylinder liner, it is possible to process a direction nearly perpendicular to the central axis of the cylinder liner (160°< α<180°) groove-type texture, the groove-type texture close to the direction of the central axis of the cylinder liner (0°<β<20°) is processed on the two ends of the cylinder liner, and the groove-type texture The depth and width parameters of the texture are the same as those of the existing honing texture. One of the limit cases is that the middle part is a groove-shaped stripe perpendicular to the direction of the central axis of the cylinder liner, and the two ends are groove-shaped stripes parallel to the direction of the central axis of the cylinder liner.

Compared with the existing platform honing texture structure on the inner wall of the cylinder liner, the invention has a lower friction coefficient. When the piston and piston ring are in the middle of the cylinder liner, it can produce better oil film bearing capacity, and when the piston and piston ring are in the two ends of the cylinder liner, it can better obtain the supply of lubricating oil in the groove-shaped stripes. Thus, the lubricating performance of the cylinder liner is further improved, and its service life is increased.

Description of drawings:

Fig. 1 is a schematic diagram of the honing texture on the inner wall of the existing cylinder liner;

Fig. 2 is a distribution diagram of honing pattern with variable angles in the direction of the central axis of the inner wall of the cylinder liner of the present invention;

Fig. 3 is the limiting condition of honing stripes with variable angles along the central axis of the cylinder liner;

The names of the symbols in the figure: 1 is the inner wall of the cylinder liner, 2 is the honing texture, 3 is the groove type texture close to the direction parallel to the central axis of the cylinder liner, 4 is the groove type texture close to the direction perpendicular to the central axis of the cylinder liner , 5 is a groove-shaped stripe parallel to the direction of the central axis of the cylinder liner, and 6 is a groove-shaped stripe perpendicular to the direction of the central axis of the cylinder liner. the

Detailed ways:

Before implementation, a simulation experiment was carried out first. Groove stripes with a depth of 7 μm and a width of 100 μm were processed on the cylinder liner specimen, and the angles between the groove direction and the moving direction of the specimen were 0°, 45° and 90°, respectively. The test was carried out on a reciprocating testing machine. During the test, the crank speed of the testing machine is 50-500r/min, that is, the maximum linear velocity experienced by the specimen is 0.21-2.1m/s, and the test load is 0.5MPa. After the test, when the crank speed is 50r/min, the friction coefficient of the specimen with 0° groove stripes is 0.03402, the friction coefficient of the specimen with 45° groove stripes is 0.03725, and the friction coefficient of the specimen with 90° groove stripes is 0.04177. When the crank speed is 200r/min, the friction coefficients of the specimens with 0°, 45° and 90° groove stripes are 0.02995, 0.03177 and 0.03011, respectively. When the crank speed is 500r/min, the friction coefficients of the specimens with 0°, 45° and 90° groove stripes are 0.02761, 0.02526 and 0.02217, respectively. It can be seen from the test results that when the speed is low, the specimen with the groove angle of 0° has the lowest friction coefficient. As the speed increases, the specimen with the groove angle of 90° gradually exhibits the lowest friction coefficient. In actual engine work, the speed experienced by the middle part of the cylinder liner is often greater than 7m/s, while the speed experienced by the two ends is still 0m/s. Therefore, it is expected that the groove pattern of 160°<α<180° will be processed in the middle of the cylinder liner, and the groove pattern of 0°<β<20° at both ends of the cylinder liner will make the cylinder liner have a lower coefficient of friction.

The present invention proposes to carry out different honing texture designs in the direction of the central axis of the cylinder liner, and is implemented on the premise of the technical solution of the present invention. Specifically, by controlling the movement of the honing head, the honing pattern is processed in the middle of the cylinder liner close to the direction of the central axis of the cylinder liner. The proportion of the processed part is 1/2-2/3 of the length of the cylinder liner. Both ends of the cylinder liner are symmetrically machined with a honing texture close to the direction parallel to the central axis of the cylinder liner. During processing, during the upward movement of the honing head, the honing head is rotated at a low speed, fed rapidly to process the top of the cylinder liner, and then increases the speed of rotation, reduces the feed speed to process the middle part of the cylinder liner, and then reduces the rotation Movement speed, rapid feed to process the bottom of the cylinder liner. During the downward movement of the honing head, its speed change is the same as the above process. After processing, the top processing part of the cylinder liner and the bottom processing part are symmetrical to the midpoint of the central axis of the cylinder liner.

Claims (2)

1. A low-friction axial unequal angle platform honing cylinder liner, characterized in that: the middle part of the inner wall of the cylinder liner has a groove-type texture of 160°<α<180°, where α is the platform honing of the middle part of the cylinder liner The included angle of the reticulation in the direction of the central axis of the cylinder liner; the two ends of the inner wall of the cylinder liner have a groove type reticulation of 0°<β<20°, where β is the platform honing reticulation at both ends of the cylinder liner. The mesh angle in the direction of the central axis. 2. The low-friction axial unequal-angle platform honing cylinder liner according to claim 1, characterized in that: α=180°, β=0°.

Images