Roller of fuel pump of internal combustion engine

Abstract

The invention aims to provide the roller of the fuel pump of the internal combustion engine, so that the abrasion probability of a transmission part is reduced under the conventional working condition, and the quality risk is reduced. And the product reliability is improved to the greatest extent. According to the idler wheel of the fuel pump of the internal combustion engine, the outer contour line of the working face of the idler wheel in the axis direction comprises a first chamfer section, a first arc section, an outer protruding section, a second arc section and a second chamfer section which are sequentially connected; the outer convex section protrudes outwards relative to the first arc section and the second arc section; the first chamfer section is connected with a first radial surface of the roller, and the second chamfer section is connected with a second radial surface of the roller.

Description

Technical Field

[0001] The invention belongs to the field of internal combustion engine fuel pump transmission, and in particular relates to a roller of an internal combustion engine fuel pump. Background Art

[0002] The roller is an important transmission component in the fuel pump and an important structure of the mechanical transmission between the fuel pump and the cam box. Its working condition has a direct impact on the performance of the fuel injection pump. In order to meet the power, economy and emission requirements of modern new diesel engines, more and more models require higher fuel injection pressure, which increases the load between the fuel pump and the cam box, which in turn increases the mechanical wear between the roller and the cam. The wear caused by uneven force will cause the roller assembly to fail to transmit normally, resulting in seizure, and even failure of the entire fuel pump system.

[0003] At present, the conventional outer circle design of rollers is divided into two types: straight line and arc (drum) shape. When the straight line roller is subjected to the lifting force of the cam, it will produce plastic deformation to form a concave surface. All stresses are concentrated on both sides near the chamfer, which can easily lead to abnormal wear of the stress concentration point. However, due to processing problems, the arc (drum) roller cannot stably ensure that the symmetry of the arc is less than 0.001, resulting in uneven force on both sides. It is also easy to cause local wear under heavy loads, affecting the service life of the roller. Summary of the invention

[0004] The present invention is intended to provide a roller for an internal combustion engine fuel pump, which can reduce the wear probability of transmission components under normal working conditions, reduce quality risks, and maximize the reliability of the product.

[0005] To achieve the above object, the basic scheme of the present invention is as follows: The present application provides a roller for an internal combustion engine fuel pump, wherein the outer contour line of the working surface of the roller along the axis direction comprises: a first chamfered section, a first arc section, an outer convex section, a second arc section and a first chamfered section connected in sequence; The convex section bulges outward relative to the first arc section and the second arc section; The first chamfered section is connected to a first radial surface of the roller, and the second chamfered section is connected to a second radial surface of the roller.

[0006] Preferably, the first arc segment is tangent to the convex segment, and the second arc segment is tangent to the convex segment.

[0007] Preferably, the first arc segment is tangent to the first chamfer, and the second arc segment is tangent to the second chamfer.

[0008] Preferably, the length of the outer convex section along the axial direction is 40%-70% of the length of the contour line of the working surface of the roller along the axial direction.

[0009] Preferably, the radii of the first arc segment and the second arc segment are between 800 mm and 2000 mm.

[0010] Beneficial effects of this program: (1) The roller profile structure of the present invention is composed of three parts, namely, an outer convex cylinder, a chamfer and a large arc tangent thereto. The structure is simple, and the three-level structure balances the force, thereby maximizing the reliability of the product.

[0011] (2) When the transmission roller is lifted by the cam, the first convex cylinder in contact will first produce plastic deformation. The plastic deformation will spread to the large arc as the stress increases. When the large arc is subjected to external force, it will also deform, and the stress will gradually spread to the outer large arc. This design makes the stress on the entire roller outer surface evenly diffused. It reduces the quality risk caused by excessive stress concentration and increases the service life of the product.

[0012] (3) Due to the existence of the convex cylinder, the stress at the extreme positions of the two ends of the large arc is greatly neutralized, so that even if the overall outer line is offset to the left or right, the force is evenly extended from the central convex cylinder to the large arc. Therefore, it is not necessary to have a high degree of symmetry for the large arc to ensure the stable operation of the transmission parts. And because the large arc and the convex cylinder are tangent to each other, conventional rotary methods (such as lathe processing) can be used for processing, which is simple and has higher structural strength of the parts.

[0013] (4) According to the daily use of the product, stress concentration mainly occurs near the two end faces. The structure is designed with chamfers on both sides of the large arc, so that even if stress concentration occurs, the plastic deformation caused will not cause the parts to bite, reducing quality risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the outer contour line of the roller of the internal combustion engine fuel pump in the axial direction in the embodiment of the present application; Figure 2 It is a schematic diagram of the finite element analysis of the outer circle of the roller in the embodiment of the present application; Figure 3 It is a stress analysis line graph of the outer circle of the roller in the embodiment of the present application. DETAILED DESCRIPTION

[0015] Reference Figure 1 , the embodiment of the present application provides a roller of an internal combustion engine fuel pump, wherein the contour line of the working surface of the roller along the axial direction comprises: a first chamfered section, a first arc section, an outer convex section, a second arc section and a first chamfered section connected in sequence; The convex section bulges outward relative to the first arc section and the second arc section; The first chamfered section is connected to a first radial surface of the roller, and the second chamfered section is connected to a second radial surface of the roller.

[0016] When the fuel engine is running, the crankshaft drives the cam to rotate, and the cam acts on the roller in a lifting manner. The outer contour line of the roller of the internal combustion engine fuel pump of the present invention in the axial direction is as follows: Figure 1 As shown, the outer contour line of the roller of the internal combustion engine fuel pump in the axial direction includes: a first chamfered section, a first arc section, a convex section, a second arc section and a first chamfered section connected in sequence. The convex section refers to the convex cylinder 11 on the roller, the first arc section and the second arc section refer to the large arcs set on both sides of the convex cylinder 11, and the first chamfered section and the second chamfered section refer to the chamfers 13 set outside the two large arcs.

[0017] When the transmission roller is squeezed by the cam, the outer convex cylinder 11 on the roller that first contacts the cam will first undergo plastic deformation. As the stress increases, the plastic deformation will spread to the large arcs 12 connected on both sides of the outer convex cylinder 11. When the large arc 12 is subjected to external force, it will also deform, and the stress will gradually spread to the chamfers 13 on the outer layer. Figure 2 and Figure 3 Stress analysis diagram is shown in Fig.

[0018] This design makes the stress on the outer surface of the entire internal combustion engine fuel pump roller evenly dispersed, and the stress difference on the entire outer circle of the roller does not exceed 120MPa, which is a completely acceptable range for transmission components (the conventional stress difference is generally around 250MPa). In other words, due to the existence of the convex cylinder 11, the stress on the extreme positions at both ends of the large arc 12 is greatly neutralized, effectively solving the problem of stress concentration at both ends caused by plastic deformation.

[0019] The present invention can also solve the problems of conventional outer profile lines in processing. Conventional large arc designs of roller outer circles usually adopt a grinding method. Due to design problems, the closer to the left and right ends, the greater the wear, resulting in uneven wear of the grinding wheel as a whole. Most of the time is spent on grinding the grinding wheel, and it is difficult to effectively ensure the quality. However, this design adopts the form of large arc 12 + convex cylinder 11 + large arc 12 tangent transition (that is, the first arc segment is tangent to the convex segment, and the second arc segment is also tangent to the convex segment). Figure 2 Finite element analysis shows that the structure of the convex cylinder 11 neutralizes most of the stress at the extreme positions of both ends. It is not necessary to have high symmetry requirements for the large arc 12 to ensure uniform stress on the entire outer surface. And because the large arc 12 and the convex cylinder 11 are tangent, conventional rotation methods (such as lathing) can be used for processing, which is simple and has higher structural strength of the parts.

[0020] The invention can also be designed according to transmission parts of different sizes. According to the results of long-term tests, as long as the proportion of the convex cylinder 11 on the entire outer circle meets 40%-70% (that is, the length of the convex section along the axial direction is 40%-70% of the length of the contour line of the working surface of the roller along the axial direction), under this proportion of the convex cylinder, the force of the large arc 12 can be more effectively balanced, the quality risk of excessive stress concentration can be reduced, and the service life of the product can be increased.

[0021] From the cross-section, the radius of the first arc segment and the second arc segment is between 800mm and 2000mm. Due to the existence of the convex cylinder 11, the stress at the extreme positions of the two ends of the large arc 12 is greatly neutralized, so that even if the outer contour of the roller is offset to the left or right as a whole, the force is evenly extended from the central convex cylinder 11 to the arc.

[0022] There are chamfers 13 tangent to the large arc 12 at both ends. When the stress is concentrated near the end face, the plastic deformation caused will not cause the parts to bite.

[0023] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0024] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A roller for an internal combustion engine fuel pump, characterized in that: The outer contour line of the working surface of the roller along the axis direction includes: a first chamfered section, a first arc section, an outer convex section, a second arc section and a first chamfered section connected in sequence; The convex section bulges outward relative to the first arc section and the second arc section; The first chamfered section is connected to a first radial surface of the roller, and the second chamfered section is connected to a second radial surface of the roller.

2. The roller of the internal combustion engine fuel pump according to claim 1, characterized in that: The first arc segment is tangent to the convex segment, and the second arc segment is tangent to the convex segment.

3. The roller of the internal combustion engine fuel pump according to claim 1, characterized in that: The first arc segment is tangent to the first chamfer, and the second arc segment is tangent to the second chamfer.

4. The roller of the internal combustion engine fuel pump according to claim 1, characterized in that: The length of the outer convex section along the axial direction is 40%-70% of the length of the contour line of the working surface of the roller along the axial direction.

5. The roller of the internal combustion engine fuel pump according to claim 1, characterized in that: The radii of the first arc segment and the second arc segment are between 800 mm and 2000 mm.

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