Camshaft bushing for diesel engine

Abstract

The utility model relates to a camshaft bushing for a diesel engine, which comprises a bushing body and two bushing upper oil holes arranged on the bushing body, and is characterized in that the bushing body is provided with a special-shaped oil groove; the special-shaped oil groove comprises a longitudinal main oil duct and at least two transverse flow dividing oil ducts, and the two transverse flow dividing oil ducts are arranged on the two sides of the longitudinal main oil duct respectively and communicated with the longitudinal main oil duct. According to the utility model, by adding the special-shaped oil groove and angle control, under the condition that original functions are not changed, an oil film between the bushing and the cam shaft is fully established, early grinding of the bushing and the cam shaft is avoided, the lubricating effect of the cam shaft and the bushing is improved, and the product failure rate is reduced. In addition, a copper-based sleeve rolling process is adopted, so that the production process of the bushing is simple, and the development cost is relatively low.

Description

Technical Field

[0001] The utility model relates to a camshaft bushing, in particular to a camshaft bushing for a diesel engine. Background Art

[0002] At present, most camshaft bushings of diesel engines adopt aluminum-based rolled bushings. There are two oil supply holes at the gear end of some engines. Through the semi-circular groove of the camshaft, during the rotation of the camshaft, the oil channels in the semi-circular groove of the camshaft are communicated with the inlet and outlet holes on the bushing to continuously supply oil intermittently to the top rocker arm. In the process from the start to the initial running-in of the engine, except for the lubricating oil near the two oil holes on the bushing, the lubricating oil between the bushing and the camshaft is established relatively slowly at the positions far from the oil holes, and it is difficult to establish an oil film. Poor lubrication will lead to early dry grinding between the bushing and the camshaft. The clearance between the camshaft and the bushing is relatively small, and dry grinding causes thermal deformation of the hot bushing, which in turn causes the camshaft bushing and the camshaft to jam. The bushing and the body hole produce relative sliding, blocking the oil supply hole, resulting in the lubricating oil being unable to reach the rocker arm through the smooth oil channel, ultimately leading to dry grinding damage of the rocker arm without oil supply. At the same time, the clearance between the camshaft bushing and the camshaft hole of the body is large. Under the action of the front gear, the camshaft is stressed and fractured, ultimately resulting in damage to the normal mechanical function of the engine, seriously affecting the performance and reliability. Summary of the Utility Model

[0003] The utility model aims to provide a camshaft bushing for a diesel engine, which can solve the problem that during the first start-up, running-in and normal operation of the front camshaft bushing of the diesel engine, a uniform oil film cannot be generated on the surfaces of the bushing and the camshaft as soon as possible, resulting in wear of the bushing, thermal expansion of the bushing and seizure with the camshaft, and further leading to problems such as no oil supply to the rocker arm and broken camshaft.

[0004] To solve the above problems, the technical solution adopted by the utility model is as follows:

[0005] A camshaft bushing for a diesel engine includes a bushing body, and two oil supply holes are opened on the bushing body. The special feature is that:

[0006] The bushing body has a special-shaped oil groove;

[0007] The special-shaped oil groove includes a longitudinal main oil channel and at least two transverse diversion oil channels. The two transverse diversion oil channels are respectively arranged on both sides of the longitudinal main oil channel and are communicated with it.

[0008] Further, the two transverse diversion oil channels are respectively vertically or obliquely communicated with both sides of the longitudinal main oil channel.

[0009] Further, the number of the transverse diversion oil channels can be several.

[0010] Further, the circumferential extension line of the center line of the longitudinal main oil passage passes through the centers of the upper oil holes of the two bushings.

[0011] Further, the bushing body is manufactured by a rolling sleeve process.

[0012] Further, the bushing body is made of a copper-based material.

[0013] Further, the two ends of the bushing body for rolling butt joint are respectively provided with a bushing buckle boss and a bushing buckle pit.

[0014] Further, when the camshaft rotates to a predetermined position, one end of the semi-circular oil groove of the camshaft is communicated with the longitudinal main oil passage of the special-shaped oil groove, and the other end is communicated with the upper oil hole of the adjacent bushing, that is, the semi-circular oil groove of the camshaft simultaneously conducts the special-shaped oil groove and the upper oil hole of the bushing.

[0015] A camshaft bushing for a diesel engine according to the present utility model, by adding a special-shaped oil groove and controlling the angle, fully establishes an oil film between the bushing and the camshaft while ensuring the original functions remain unchanged, avoids premature wear between the bushing and the camshaft, improves the lubrication effect between the camshaft and the bushing, and reduces the product failure rate. In addition, the copper-based rolling sleeve process is adopted, making the production process of the bushing simple and the development cost relatively low. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 : The developed structure diagram of the camshaft bushing in Embodiment 1;

[0017] Figure 2 : Figure 1 The finished product structure diagram of the camshaft bushing after the camshaft bushing in [] is rolled;

[0018] Figure 3 : Figure 2 The A-A cross-sectional view in [];

[0019] Figure 4 : Figure 3 The B-B rotating cross-sectional view in [];

[0020] Figure 5 : The installation structure and oil circuit layout diagram of the bushing, the body and the camshaft;

[0021] Figure 6 : Figure 5 The C-C cross-sectional view in [];

[0022] Figure 7 : Figure 6 The first local enlarged state diagram at P in [];

[0023] Figure 8 : Figure 6 The second local enlarged state diagram at P in [];

[0024] In the figure, 1. bushing buckle boss, 2. first oil hole on the bushing, 3. second oil hole on the bushing, 4. special-shaped oil groove, 5. bushing buckle pit, 6. body, 7. camshaft, 8. camshaft bushing, 9. oil passage from the body to the first oil hole on the bushing, 10. oil passage from the bushing to the body to the rocker arm, 11. semi-circular groove with a long hole along the camshaft. Specific implementation mode

[0025] The following will make the following detailed description of the present invention with reference to the drawings.

[0026] Embodiment 1

[0027] A camshaft bushing for a diesel engine is made of a copper-based material by a rolling sleeve process, and includes a bushing body, a first oil hole 2 on the bushing body, a second oil hole 3 on the bushing body, and a special-shaped oil groove 4; its structure is as Figures 1-4 shown, where Figure 1 is the unfolded state diagram of the bushing, Figures 2-4 is the structure diagram of the finished bushing; the special-shaped oil groove is composed of a longer longitudinal main oil passage and two transverse shunt oil passages with different lengths. The width of the oil groove is 1 mm, the depth is 0.5 mm, and the burrs are removed by a 45° chamfer (the width and depth of the oil groove can be designed according to specific design requirements); according to the hole position size requirements of the actual installation, the position dimensions of the first oil hole 2 on the bushing, the second oil hole 3 on the bushing, and the special-shaped oil groove 4 are determined, and the product is produced according to the Figure 1 unfolded diagram (the reference angle on the unfolded diagram only illustrates a reference angle, which is not limited to this angle and is set according to specific dimension layout requirements). After the production is completed, the bushing is rolled by a mold, and the bushing buckle boss 1 and the bushing buckle pit 5 are closed, and finally the Figure 2 state, that is, the camshaft bushing 8 is formed. The buckle rolling scheme is adopted to reduce the complexity of the processing technology and the cost of the product.

[0028] Figures 5-6Shown is the installation structure of the bushing, the body and the camshaft and the oil circuit layout diagram, specifically including the body 6, the camshaft 7, the camshaft bushing 8, the oil passage 9 from the body to the oil hole on the bushing, the oil passage 10 from the bushing to the body to the rocker arm, and the semi-circular groove 11 of the oil hole on the camshaft. The installation hole between the camshaft bushing 8 and the body 6 is an interference fit and is pressed by a special pressure device, that is, the camshaft bushing 8 and the body 6 do not produce relative sliding. The camshaft 7 is assembled in the camshaft bushing 8, and the two are in a clearance fit. There is an oil film between the camshaft 7 and the camshaft bushing 8 for lubrication. The lubricating oil reaches the oil passage 9 from the body to the oil hole on the bushing along the direction of the arrow in the figure through the pressure of the bottom oil passage. During the rotation of the camshaft 7, the semi-circular groove 11 of the oil hole on the camshaft conducts the oil passage 9 from the body to the oil hole on the bushing to the oil passage 10 from the bushing to the body to the rocker arm and the special-shaped oil groove 4, realizing intermittent oil supply to the rocker arm on the cylinder head and filling the weak area of the oil film between the bushing and the camshaft at the initial stage of engine starting.

[0029] Figure 7 It is the process of filling the weak area of the oil film between the bushing and the camshaft at the initial stage of engine starting after adding a special-shaped oil groove to the bushing. During the rotation of the camshaft 7, the right end port of the semi-circular groove 11 of the oil hole on the camshaft just starts to conduct with the second oil hole on the bushing, and the left end port conducts with the longitudinal main oil passage in the special-shaped oil groove 4. At this time, the lubricating oil in the oil passage 9 from the body to the oil hole on the bushing is introduced into the special-shaped oil groove 4 of the bushing through the second oil hole on the bushing and the semi-circular groove 11 of the oil hole on the camshaft. Through the left and right transverse diversion oil passages of the special-shaped oil groove 4, during the oil filling process of the camshaft rotation, a sufficient oil film is quickly established in the original weak area of the cavity between the bushing and the camshaft bushing. The oil filling process continues until the left end port of the semi-circular groove 11 of the oil hole on the camshaft does not coincide with the special-shaped oil groove 4.

[0030] Figure 8 It is the conduction process of the left and right end ports of the semi-circular groove 11 of the oil hole on the camshaft with the second oil hole on the bushing and the second oil hole on the bushing. The lubricating oil reaches the cylinder head through the oil passage 9-3-11-2-10 established above and supplies oil to the rocker arm. During this process, the left and right end ports of the semi-circular groove of the oil hole on the camshaft no longer contact the special-shaped oil groove 4 of the bushing, that is, the original oil supply amount to the rocker arm will not be damaged.

[0031] A camshaft bushing for a diesel engine in this embodiment has the following technical advantages compared with the traditional camshaft bushing:

[0032] 1. The design of the bushing material is improved. To improve the wear resistance of the bushing, the bushing is changed from an aluminum-based material to a copper-based material. At the same time, to reduce the product cost, a rolled sleeve process is selected for the bushing.

[0033] 2. Design improvements are made structurally by adding special-shaped oil grooves to the bushing, a longitudinal main oil passage and two transverse shunt oil passages that communicate with it. As the camshaft rotates, the semi-circular oil groove of the camshaft conducts the oil inlet hole and the special-shaped oil groove. The lubricating oil passes through the established oil passages and finally evenly covers the area where the oil film on the bushing is established slowly. By using the rotation of the camshaft, a uniform oil film is established on the entire bushing during the engine startup to the running-in period, avoiding early dry friction and reducing the failure rate. In addition, the arrangement of the oil grooves does not overlap with the period when oil is supplied to the rocker arm, that is, the proposed arrangement does not affect the original oil supply to the rocker arm.

Claims

1. A camshaft bushing for a diesel engine, comprising a bushing body and two bushing oil holes provided on the bushing body, characterized in that: The bushing body has a special-shaped oil groove; The special-shaped oil groove comprises a longitudinal main oil passage and at least two transverse branch oil passages, wherein the two transverse branch oil passages are arranged on both sides of the longitudinal main oil passage and are connected with the longitudinal main oil passage.

2. A camshaft bushing for a diesel engine as claimed in claim 1, characterized in that: The two transverse branch oil passages are respectively vertically or obliquely connected to the two sides of the longitudinal main oil passage.

3. A camshaft bushing for a diesel engine as claimed in claim 2, characterized in that: The circumferential extension line of the center line of the longitudinal main oil channel passes through the centers of the oil holes on the two bushings.

4. A camshaft bushing for a diesel engine as claimed in claim 1, characterized in that: The bushing body is made by adopting a rolling sleeve process.

5. A camshaft bushing for a diesel engine as claimed in claim 1, characterized in that: The bushing body is made of copper-based material.

6. A camshaft bushing for a diesel engine as claimed in claim 1, characterized in that: The two ends of the bushing body for rolling and docking are respectively provided with bushing buckle bosses and bushing buckle pits.

7. A camshaft bushing for a diesel engine as claimed in claim 1, characterized in that: When the camshaft rotates to a predetermined position, one end of the semicircular oil groove of the camshaft is connected to the longitudinal main oil channel of the special-shaped oil groove, and the other end is connected to the oil hole on the adjacent bushing, that is, the semicircular oil groove of the camshaft simultaneously connects the special-shaped oil groove and the oil hole on the bushing.

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