Engine rocker arm assembly

Abstract

This invention discloses an engine rocker arm assembly. The rocker arm seat is fixed to the engine cylinder head. The rocker arm seat has a rocker arm seat shaft hole, and rocker arms are respectively provided on both sides of the rocker arm seat. Each rocker arm has a rocker arm shaft hole. The rocker arm shaft is connected to the rocker arm seat and the rocker arm through the rocker arm seat shaft hole and the rocker arm shaft hole, respectively. The rocker arm shaft and the rocker arm seat shaft hole have a clearance fit, as do the rocker arm shaft and the rocker arm shaft hole. The rocker arm seat has a rocker arm seat oil passage hole, and the inner wall of the rocker arm shaft hole has an arm hole oil groove. The rocker arm shaft has multiple rocker arm shaft oil passages, which are respectively connected to the rocker arm seat oil passage hole and the arm hole oil groove. The engine rocker arm assembly adopts a bushingless floating shaft structure, which can improve the reliability of the rocker arm assembly connection, avoid component failure due to excessive initial wear, and avoid frequent bushing replacements, thus reducing maintenance and operating costs.

Description

Technical Field

[0001] This invention relates to the field of engine technology, and more specifically to an engine rocker arm assembly. Background Technology

[0002] The rocker arm assembly, used on the engine cylinder, is one of the important components of engine operation. The engine rocker arm assembly includes the rocker arm, rocker arm mount, and rocker arm shaft. The rocker arm and rocker arm shaft are supported on the cylinder head via the rocker arm mount. The rocker arm is mounted on the rocker arm mount via the rocker arm shaft. Typically, the rocker arm is a double-arm lever that reciprocates around the rocker arm shaft as a fulcrum. The opening and closing of the valves is accomplished by the action of the tappet and the rocker arm. One end of the rocker arm is driven by the camshaft via the tappet, while the other end rests against the valve stem and works with a spring to control the opening and closing of the valve.

[0003] like Figure 1 As shown, the traditional rocker arm assembly structure is as follows: a section of the rocker arm shaft 3' is fixedly connected to the rocker arm seat 1' by screws 4'. The rocker arm 2' has a rocker arm shaft hole 201', and the rocker arm 2' is fitted onto the rocker arm shaft 3' at the rocker arm shaft hole 201'. The rocker arm 2' can rotate relative to the rocker arm shaft 3'. During operation, the area where the rocker arm shaft 3' and the rocker arm 2' meet is subjected to long-term stress, leading to excessive local wear, affecting the establishment of the lubricating oil film, and causing premature failure of the rocker arm shaft 3'. To solve the problem of excessive initial wear between the rocker arm and the rocker arm shaft, traditional rocker arm assemblies usually install a bushing between the rocker arm shaft hole and the rocker arm shaft to prevent oil film damage and adhesion problems caused by foreign matter after local wear of the rocker arm shaft. However, after a period of use, the bushing will wear out and needs to be replaced, reducing the reliability of the valve train mechanism. At the same time, frequent bushing replacement increases maintenance and operating costs. In addition, in the existing technology, the rocker arm seat will creep relative to the cylinder head during operation, causing the installation mating surface between the rocker arm seat and the cylinder head to separate, which in turn causes the oil film at the mating surface to fail, resulting in failures such as initial wear, jamming and adhesion. Summary of the Invention

[0004] In view of the above-mentioned defects in the prior art, the technical problem to be solved by the present invention is to provide an engine rocker arm assembly with a bushingless floating shaft structure, which can improve the reliability of the rocker arm assembly connection, avoid component failure due to excessive initial wear, and reduce maintenance and use costs.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] An engine rocker arm assembly includes: a rocker arm seat, a rocker arm, and a rocker arm shaft. The rocker arm seat is fixed to the cylinder head of the engine. The rocker arm seat has a rocker arm seat shaft hole. Rocker arms are respectively provided on both sides of the rocker arm seat. Each rocker arm has a rocker arm shaft hole. The rocker arm shaft is connected to the rocker arm seat and the rocker arm through the rocker arm seat shaft hole and the rocker arm shaft hole, respectively. The key feature is that...

[0007] The rocker arm shaft is clearance-fitted with the rocker arm seat shaft hole. The rocker arm seat has a rocker arm seat oil passage hole. The inner wall of the rocker arm shaft hole has an arm hole oil groove. The rocker arm shaft has multiple rocker arm shaft oil passages. The multiple rocker arm shaft oil passages are respectively connected to the rocker arm seat oil passage hole and the arm hole oil groove.

[0008] Preferably, the cylinder head and the rocker arm seat have a surface pressure adjustment groove on their mounting surfaces to prevent the rocker arm seat from creeping.

[0009] Preferably, the cylinder head has an oil inlet hole, and the surface pressure adjusting groove is connected to the oil inlet hole and the rocker arm seat oil passage hole.

[0010] Preferably, the clearance between the rocker arm shaft and the rocker arm seat shaft hole is H1, where 0.05mm≤H1≤0.12mm.

[0011] Preferably, the clearance H2 between the rocker arm shaft and the rocker arm shaft hole is 0.03mm≤H2≤0.10mm.

[0012] Preferably, rocker arm retaining rings that limit the axial movement of the rocker arm shaft are respectively installed at both ends of the rocker arm shaft, and the gap between the end face of the rocker arm retaining ring and the end face of the rocker arm is H3, 0.3mm≤H3≤0.5mm.

[0013] Preferably, the arm hole oil groove is configured as an arc-shaped groove, with the center angle of the arc-shaped groove being θ, where 80°≤θ≤90°, and the arc-shaped groove is located on the upper part of the inner wall of the rocker arm shaft hole.

[0014] Preferably, the rocker arm is connected to a valve crossarm top and a push rod top at both ends, and a rocker arm oil passage hole is also provided on the rocker arm. The rocker arm oil passage hole is connected to the arm hole oil groove. One end of the rocker arm oil passage hole leads to the valve crossarm top and the other end leads to the push rod top.

[0015] Preferably, the plurality of rocker arm shaft oil passages on the rocker arm shaft include a first radial oil hole, a second radial oil hole, a third radial oil hole, an axial oil hole, a first annular oil groove, a second annular oil groove, and a third annular oil groove. The axial oil hole is arranged along the axial direction of the rocker arm shaft, and the first annular oil groove, the second annular oil groove, and the third annular oil groove are respectively arranged along the circumference of the rocker arm shaft.

[0016] The rocker arms located on both sides of the rocker arm seat include a first rocker arm and a second rocker arm. The first annular oil groove is provided corresponding to the arm hole oil groove of the first rocker arm, the second annular oil groove is provided corresponding to the arm hole oil groove of the second rocker arm, and the third annular oil groove is provided corresponding to the oil passage hole of the rocker arm seat.

[0017] The first radial oil hole is radially arranged at the first annular oil groove, the second radial oil hole is radially arranged at the second annular oil groove, and the third radial oil hole is radially arranged at the third annular oil groove. The first annular oil groove, the second annular oil groove, and the third annular oil groove are respectively connected to the axial oil hole through the first radial oil hole, the second radial oil hole, and the third radial oil hole.

[0018] Preferably: the axial oil hole is located at the center of the rocker arm shaft, and a plug is installed at the opening end of the axial oil hole. Let L1 be the distance between the end of the plug hole where the plug is installed and the oil groove of the first rocker arm, and L2 be the distance between the end of the axial oil hole and the oil groove of the second rocker arm. Let 5mm≤L1≤8mm, 2mm≤L2≤3mm, 2L3 be the axial length of the mating surface between the first rocker arm and the rocker arm shaft, and L4 be the width of the first annular oil groove. Let L3=(1.8~2)L4, 2L5 be the axial length of the mating surface between the rocker arm seat and the rocker arm shaft, and L6 be the width of the third annular oil groove. Let L5=(1.3~1.5)L6.

[0019] After adopting the above technical solution, the beneficial effects of the present invention are:

[0020] The engine rocker arm assembly of the present invention has a rocker arm seat fixed to the cylinder head of the engine. The rocker arm seat has a rocker arm seat shaft hole, and rocker arms are respectively provided on both sides of the rocker arm seat. The rocker arms have rocker arm shaft holes, and the rocker arm shaft is connected to the rocker arm seat and the rocker arm through the rocker arm seat shaft hole and the rocker arm shaft hole, respectively. The rocker arm shaft and the rocker arm seat shaft hole are clearance-fitted, and the rocker arm shaft and the rocker arm shaft hole are clearance-fitted. The rocker arm seat has a rocker arm seat oil passage hole, and the inner wall of the rocker arm shaft hole has an arm hole oil groove. The rocker arm shaft has multiple rocker arm shaft oil passages, which are respectively connected to the rocker arm seat oil passage hole and the arm hole oil groove. Because the rocker arm seat and the rocker arm are clearance-fitted, there is no bushing in between; the rocker arm and the rocker arm shaft are also clearance-fitted, and there is no bushing in between. During operation, the rocker arm swing drives the rocker arm shaft to rotate freely, avoiding prolonged local stress on the rocker arm shaft, thereby preventing the rocker arm shaft from failing due to excessive local wear. Because the rocker arm shaft can rotate freely, the relative oscillation linear velocity between the rocker arm and the rocker arm shaft is reduced. At the same time, there is no prolonged localized stress, resulting in less heat generation. The lubrication channels on the rocker arm shaft, rocker arm seat, and rocker arm ensure sufficient lubrication, improve the inclusiveness of lubrication and cooling of the rocker arm and rocker arm shaft, eliminate the need for additional bushings, significantly improve the reliability of the system, and reduce manufacturing costs.

[0021] The engine rocker arm assembly is well lubricated. Lubricating oil enters the rocker arm seat oil passage through the oil inlet hole in the cylinder head, then enters the rocker arm through the rocker arm shaft oil passage on the rocker arm shaft, and finally flows into the crossarm top and pushrod top through the rocker arm hole oil groove and rocker arm oil passage hole. This avoids excessive initial wear between the rocker arm and rocker arm shaft, and between the rocker arm seat and rocker arm shaft, thus extending the service life of each component. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of an engine rocker arm assembly in the prior art;

[0023] Figure 2 A schematic diagram of the structure of an engine rocker arm assembly provided in an embodiment of the present invention;

[0024] Figure 3 yes Figure 2 Schematic diagram of the cross section at point AA;

[0025] Figure 4 yes Figure 2 Enlarged schematic diagram of the rocker arm assembly;

[0026] Figure 5 This is a schematic diagram of the mating surface between the cylinder head and the rocker arm seat;

[0027] Figure 6 This is a top view of the engine rocker arm assembly mounted on the cylinder head.

[0028] Figure 1 In the middle: 1', rocker arm seat; 2', rocker arm; 201', rocker arm shaft hole; 3', rocker arm shaft; 4', screw;

[0029] Figures 2 to 6 In the middle: 1. Rocker arm seat; 101. Rocker arm seat oil passage hole; 2. Rocker arm; 200. Rocker arm shaft hole; 201. Arm hole oil groove; 201a. Arm hole oil groove of the first rocker arm; 201b. Arm hole oil groove of the second rocker arm; 202. Rocker arm oil passage hole; 203. Threaded mounting hole; 21. First rocker arm; 22. Second rocker arm; 3. Rocker arm shaft; 301. First radial oil hole; 3010. First annular oil groove; 302. The first... Two radial oil holes; 3020, second annular oil groove; 303, third radial oil hole; 3030, third annular oil groove; 304, axial oil hole; 4, cylinder head; 401, surface pressure adjusting groove; 402, oil inlet hole; 5, plug; 6, valve crossarm top; 601, first vertical oil passage hole; 7, push rod top; 701, second vertical oil passage hole; 8, rocker arm retaining ring; 9, bolt plug; C, rocker arm seat mounting surface. Detailed Implementation

[0030] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments to further understand the purpose, solution and effect of the present invention, but it is not intended to limit the scope of protection of the appended claims.

[0031] In the description of this invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0032] Furthermore, although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used in this document do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0033] like Figure 2 and Figure 3 The engine rocker arm assembly shown includes: a rocker arm seat 1, a rocker arm 2, and a rocker arm shaft 3. The rocker arm seat 1 is fixed on the cylinder head 4 of the engine. The rocker arm seat 1 has a rocker arm seat shaft hole. Rocker arms 2 are respectively provided on both sides of the rocker arm seat 1. The rocker arms 2 have rocker arm shaft holes 200. The rocker arm shaft 3 is connected to the rocker arm seat 1 and the rocker arm 2 through the rocker arm seat shaft hole and the rocker arm shaft hole 200, respectively. The rocker arm shaft 3 is clearance-fitted with the rocker arm seat shaft hole and the rocker arm shaft hole 200. The rocker arm seat 1 has a rocker arm seat oil passage hole 101. The inner wall of the rocker arm shaft hole 200 has an arm hole oil groove 201. The rocker arm shaft 3 has multiple rocker arm shaft oil passages, which are respectively connected to the rocker arm seat oil passage hole 101 and the arm hole oil groove 201.

[0034] The rocker arm seat 1 is fixed to the cylinder head by clamping bolts and nuts. Since the rocker arm seat 1 and rocker arm 2 have a clearance fit, there is no bushing in between; similarly, the rocker arm 2 and rocker arm shaft 3 also have a clearance fit, with no bushing in between. During operation, the rocker arm 2 swings, causing the rocker arm shaft 3 to rotate freely, preventing prolonged localized stress on the rocker arm shaft 3 and thus avoiding failure due to excessive localized wear. Because the rocker arm shaft 3 can rotate freely, the relative oscillation linear velocity between the rocker arm 2 and the rocker arm shaft 3 decreases. Simultaneously, the absence of prolonged localized stress reduces heat generation. The lubrication channels on the rocker arm shaft 3, rocker arm seat 1, and rocker arm 2 ensure sufficient lubrication, improving the comprehensiveness of lubrication and cooling for both the rocker arm 2 and rocker arm shaft 3. This eliminates the need for additional bushings, significantly improving system reliability and reducing manufacturing costs.

[0035] In some embodiments, such as Figure 2 As shown, the multiple rocker arm shaft oil passages on the rocker arm shaft 3 include a first radial oil hole 301, a second radial oil hole 302, a third radial oil hole 303, an axial oil hole 304, a first annular oil groove 3010, a second annular oil groove 3020, and a third annular oil groove 3030. The axial oil hole 304 is arranged along the axial direction of the rocker arm shaft 3, and the first annular oil groove 3010, the second annular oil groove 3020, and the third annular oil groove 3030 are respectively arranged along the circumference of the rocker arm shaft 3.

[0036] like Figure 2 and Figure 5 As shown, the rocker arms 2 located on both sides of the rocker arm base 1 include a first rocker arm 21 and a second rocker arm 22. The first annular oil groove 3010 is provided corresponding to the arm hole oil groove 201a of the first rocker arm, the second annular oil groove 3020 is provided corresponding to the arm hole oil groove 201b of the second rocker arm 22, and the third annular oil groove 3030 is provided corresponding to the oil passage hole 101 of the rocker arm base.

[0037] The first radial oil hole 301 is radially provided at the first annular oil groove 3010, that is, the first radial oil hole 301 passes through the rocker arm shaft 3 radially and its two ends are located in the first annular oil groove 3010.

[0038] The second radial oil hole 302 is radially provided at the second annular oil groove 3020, that is, the second radial oil hole 302 passes through the rocker arm shaft 3 radially and its two ends are located in the second annular oil groove 3020.

[0039] The third radial oil hole 303 is radially arranged at the third annular oil groove 3030, that is, the third radial oil hole 303 passes through the rocker arm shaft 3 radially and its two ends are located within the third annular oil groove 3030. In some embodiments, it is preferable that the first radial oil hole 301 and the second radial oil hole 302 are arranged parallel to each other along the rocker arm shaft 3, while the third radial oil hole 303 is arranged perpendicular to the first radial oil hole 301 and the second radial oil hole 302. This arrangement provides better structural strength of the rocker arm shaft 3 than when all three are arranged in parallel, and it is also easier to process. Of course, the third radial oil hole 303, the first radial oil hole 301, and the second radial oil hole 302 can also be arranged alternately in space, rather than being parallel or perpendicular. This can improve the structural strength of the rocker arm shaft 3, but it will increase the processing difficulty. The first annular oil groove 3010, the second annular oil groove 3020 and the third annular oil groove 3030 are respectively connected to the axial oil hole 304 through the first radial oil hole 301, the second radial oil hole 302 and the third radial oil hole 303.

[0040] The cylinder head 4 has an oil inlet hole 402, and the surface pressure adjustment groove 401 is connected to the oil inlet hole 402 and the rocker arm seat oil passage hole 101.

[0041] refer to Figure 3 The rocker arm 2 is connected to a valve crossarm top 6 and a pushrod top 7 at its two ends, respectively. The rocker arm 2 also has a rocker arm oil passage hole 202, which communicates with the arm bore oil groove 201. One end of the rocker arm oil passage hole 202 leads to the valve crossarm top 6, and the other end leads to the pushrod top 7. The valve crossarm top 6 has a first vertical oil passage hole 601, and the pushrod top 7 has a second vertical oil passage hole 701.

[0042] In some embodiments, such as Figure 4 As shown, the axial oil hole 304 is located at the center of the rocker arm shaft 3. A plug 5 is installed at the open end of the axial oil hole 304. Let L1 be the horizontal distance between the end of the plug hole where the plug 5 is installed and the oil groove 201a of the first rocker arm 21, and L2 be the horizontal distance between the end of the axial oil hole 304 and the oil groove 201b of the second rocker arm 22. In this embodiment, 5mm≤L1≤8mm and 2mm≤L2≤3mm. The above-mentioned range of values ​​for L1 and L2 is selected to facilitate the flow of lubricating oil at the open end of the axial oil hole 304 and prevent air from accumulating, thereby ensuring normal flow of lubricating oil and avoiding cavitation at the end of the rocker arm shaft 3.

[0043] Let the axial length of the mating surface between the first rocker arm 21 and the rocker arm shaft 3 be 2L3, and the width of the first annular oil groove 3010 be L4, where L3 = (1.8~2)L4. In this embodiment, the second rocker arm 22 has the same structure as the first rocker arm 21, and the second rocker arm 22 and the first rocker arm 21 are symmetrically arranged with respect to the rocker arm seat 1. Let the axial length of the mating surface between the rocker arm seat 1 and the rocker arm shaft 3 be 2L5, and the width of the third annular oil groove 3030 be L6.

[0044] L5 = (1.3~1.5)L6. The ratios of L3 / L4 and L5 / L6 should not be too large to ensure sufficient oil flow at the end of the axial oil hole 304 and to ensure effective oil film travel. The ratios should also not be too small, as a small ratio will increase the specific pressure between the mating surfaces of rocker arm 2 and rocker arm shaft 3, and will also increase the specific pressure between the mating surfaces of rocker arm seat 1 and rocker arm shaft 3. When the specific pressure of the mating surfaces is too large, it will aggravate the initial wear when rocker arm shaft 3 mates with rocker arm 2 and rocker arm seat 1 respectively.

[0045] like Figure 5 As shown, a surface pressure adjusting groove 401 is provided on the rocker arm seat mounting surface C corresponding to the cylinder head 4 and the rocker arm seat 1 to prevent the rocker arm seat 1 from creeping. The surface pressure adjusting groove 401 can increase the surface pressure of the mounting surfaces of the cylinder head 4 and the rocker arm seat 1, ensuring that the rocker arm seat 1 does not creep during operation, so that the mounting surfaces of the cylinder head 4 and the rocker arm seat 1 do not separate. This avoids the rocker arm seat 1 from vibrating more due to creep separation, and thus avoids the destruction of the original oil film between the rocker arm seat 1 and the cylinder head 4, preventing excessive initial wear, jamming, and adhesion at the moving parts. The depth of the surface pressure adjusting groove 401 is controlled between 5mm and 6mm, which is sufficient to draw oil without throttling. The depth should not be too large, otherwise it will weaken the strength of the cylinder head. Of course, the surface pressure adjusting groove 401 should be as large as possible without affecting the strength, to ensure that the mating surfaces of the rocker arm seat 1 and the cylinder head 4 do not separate during operation, or the local separation gap does not exceed 0.01mm.

[0046] To ensure proper rotation of the rocker arm shaft 3 and rocker arm 2, the rocker arm seat 1 will experience some deformation and become out of round after being pressed and installed onto the cylinder head 4. Therefore, the clearance between the rocker arm shaft 3 and the rocker arm seat shaft hole needs to be larger to compensate for the deformation caused by pressing. Consequently, in some embodiments, the clearance between the rocker arm shaft 3 and the rocker arm seat shaft hole is preferably set to H1, where 0.05mm ≤ H1 ≤ 0.12mm.

[0047] To ensure smooth rotation of the rocker arm 2 and the rocker arm shaft 3, in some embodiments, the clearance H2 between the rocker arm shaft 3 and the rocker arm shaft hole 200 is set to 0.03mm≤H2≤0.10mm.

[0048] like Figure 2As shown, rocker arm retaining rings 8 that limit the axial movement of rocker arm shaft 3 are respectively installed at both ends of rocker arm shaft 3. The gap between the end face of rocker arm retaining ring 8 and the end face of rocker arm 2 is H3, 0.3mm≤H3≤0.5mm.

[0049] like Figure 3 As shown, the arm hole oil groove 201 is set as an arc-shaped groove, with the central angle of the arc-shaped groove being θ, where 80°≤θ≤90°. The arc-shaped groove is located on the upper part of the inner wall of the rocker arm shaft hole 200. When the rocker arm 2 swings around the rocker arm shaft 3, the lower part of the inner wall of the rocker arm shaft hole 200 is the main stress area, i.e., the area that wears faster, while the upper part of the inner wall of the rocker arm shaft hole 200 is a weak or almost stress-free area. Therefore, the arm hole oil groove 201 is set on the upper part of the inner wall of the rocker arm shaft hole 200 to prevent the arm hole oil groove 201 from being crushed.

[0050] In some embodiments, to improve the initial break-in performance of the rocker arm 2, phosphating is performed at the rocker arm shaft hole 200 to improve lubrication and prevent adhesion problems caused by local high points during the initial break-in period.

[0051] like Figure 3 As shown, to facilitate the disassembly and replacement of the valve crossarm head 6, the valve crossarm head 6 is threadedly connected to one end of the rocker arm 2. One end of the rocker arm 2 has a threaded mounting hole 203, and the valve crossarm head 6 has a threaded section that screws into the bottom of the threaded mounting hole 203. The rocker arm oil passage hole 202 is connected to the threaded mounting hole 203, allowing lubricating oil to flow from the rocker arm oil passage hole 202 to the threaded mounting hole 203. To prevent lubricating oil in the threaded mounting hole from being thrown out during the rocker arm's movement, and to prevent dust and debris from entering the threaded mounting hole, a bolt plug 9 is installed at the top of the threaded mounting hole. The other end of the rocker arm 2 is threadedly fixedly connected to the push rod head 7.

[0052] The process by which lubricating oil entering from inside cylinder head 4 flows through the engine rocker arm assembly is as follows:

[0053] Cylinder head 4 oil inlet 402 — surface pressure adjustment groove 401 — rocker arm seat oil passage hole 101 — rocker arm shaft 3 third annular oil groove 3030 — third radial oil hole 303 — axial oil hole 304 — first radial oil hole 301 and second radial oil hole 302 — first annular oil groove 3010 and second annular oil groove 3020 — first rocker arm arm hole oil groove 201a and second rocker arm arm hole oil groove 201b — rocker arm oil passage hole 202 — valve cross arm top 6 and push rod top 7.

[0054] In summary, the lubricating oil of the rocker arm system enters the rocker arm seat oil passage hole 101 of the rocker arm seat 1 through the oil inlet hole 402 of the cylinder head 4, then enters the rocker arm 2 through the rocker arm shaft oil passage on the rocker arm shaft 3, and then flows into the valve cross arm top and push rod top 7 through the arm hole oil groove 201 and rocker arm oil passage hole 202 of the rocker arm 2.

[0055] The engine rocker arm assembly of the present invention employs a floating shaft structure for the rocker arm shaft 3, resulting in uniform wear between the rocker arm 2 and the rocker arm shaft 3. This avoids uneven wear between the rocker arm shaft 3 and the rocker arm 2, preventing excessive localized wear and failure. Furthermore, no bushings are required between the rocker arm shaft 3, the rocker arm 2, and the rocker arm seat 1, saving parts and avoiding frequent bushing replacements, thus reducing costs. Simultaneously, the mating surface between the rocker arm shaft 3 and the rocker arm shaft hole 200 is phosphated, significantly increasing the hardness of the mating surface and further preventing excessive initial wear.

[0056] This invention is not limited to the above embodiments. All improvements made based on the concept, principle, structure and method of this invention are within the protection scope of this invention.

Claims

1. An engine rocker arm assembly, comprising: A rocker arm seat (1), a rocker arm (2), and a rocker arm shaft (3) are provided. The rocker arm seat (1) is fixed on the cylinder head (4) of the engine. The rocker arm seat (1) has a rocker arm seat shaft hole. Rocker arms (2) are provided on both sides of the rocker arm seat (1). The rocker arms (2) have rocker arm shaft holes (200). The rocker arm shaft (3) is connected to the rocker arm seat (1) and the rocker arms (2) through the rocker arm seat shaft hole and the rocker arm shaft hole (200), respectively. The rocker arm shaft (3) is clearance-fitted with the rocker arm seat shaft hole, and the rocker arm shaft (3) is clearance-fitted with the rocker arm shaft hole (200) so that the rocker arm (2) can drive the rocker arm shaft (3) to rotate freely when it swings. The rocker arm seat (1) is provided with a rocker arm seat oil passage hole (101), the inner wall of the rocker arm shaft hole (200) is provided with an arm hole oil groove (201), and the rocker arm shaft (3) is provided with a plurality of rocker arm shaft oil passages, which are respectively connected to the rocker arm seat oil passage hole (101) and the arm hole oil groove (201); The rocker arm shaft (3) has multiple rocker arm shaft oil passages, including a first radial oil hole (301), a second radial oil hole (302), a third radial oil hole (303), an axial oil hole (304), a first annular oil groove (3010), a second annular oil groove (3020), and a third annular oil groove (3030). The axial oil hole (304) is arranged along the axial direction of the rocker arm shaft (3), and the first annular oil groove (3010), the second annular oil groove (3020), and the third annular oil groove (3030) are respectively arranged along the circumference of the rocker arm shaft (3). The rocker arms (2) located on both sides of the rocker arm base (1) include a first rocker arm (21) and a second rocker arm (22). The first annular oil groove (3010) is provided corresponding to the arm hole oil groove (201) of the first rocker arm (21), the second annular oil groove (3020) is provided corresponding to the arm hole oil groove (201) of the second rocker arm (22), and the third annular oil groove (3030) is provided corresponding to the oil passage hole (101) of the rocker arm base. The first radial oil hole (301) is radially disposed at the first annular oil groove (3010), the second radial oil hole (302) is radially disposed at the second annular oil groove (3020), and the third radial oil hole (303) is radially disposed at the third annular oil groove (3030). The first annular oil groove (3010), the second annular oil groove (3020), and the third annular oil groove (3030) are respectively connected to the axial oil hole (304) through the first radial oil hole (301), the second radial oil hole (302), and the third radial oil hole (303).

2. The engine rocker arm assembly as claimed in claim 1, characterized in that: The cylinder head (4) and the rocker arm seat (1) have a surface pressure adjustment groove (401) on their mounting surfaces to prevent the rocker arm seat (1) from creeping.

3. The engine rocker arm assembly as described in claim 2, characterized in that: The cylinder head (4) is provided with an oil inlet hole (402), and the surface pressure adjustment groove (401) is connected to the oil inlet hole (402) and the rocker arm seat oil passage hole (101).

4. The engine rocker arm assembly as claimed in claim 1, characterized in that: Let the clearance between the rocker arm shaft (3) and the rocker arm seat shaft hole be H1, where 0.05mm≤H1≤0.12mm.

5. The engine rocker arm assembly as claimed in claim 1, characterized in that: Let the clearance H2 between the rocker arm shaft (3) and the rocker arm shaft hole (200) be 0.03mm≤H2≤0.10mm.

6. The engine rocker arm assembly as claimed in claim 1, characterized in that: The rocker arm shaft (3) is equipped with rocker arm retaining rings (8) at both ends to limit the axial movement of the rocker arm shaft (3). The gap between the end face of the rocker arm retaining ring (8) and the end face of the rocker arm (2) is H3, 0.3mm ≤H3≤0.5mm.

7. The engine rocker arm assembly as claimed in claim 1, characterized in that: The arm hole oil groove (201) is set as an arc groove, and the center angle of the arc groove is θ, 80°≤θ≤90°. The arc groove is located on the upper part of the inner wall of the rocker arm shaft hole (200).

8. The engine rocker arm assembly as claimed in claim 1, characterized in that: The rocker arm (2) is connected to a valve cross arm top (6) and a push rod top (7) at both ends. The rocker arm (2) is also provided with a rocker arm oil passage hole (202). The rocker arm oil passage hole (202) is connected to the arm hole oil groove (201). One end of the rocker arm oil passage hole (202) leads to the valve cross arm top (6), and the other end leads to the push rod top (7).

9. The engine rocker arm assembly as claimed in claim 1, characterized in that: The axial oil hole (304) is located at the center of the rocker arm shaft (3). A plug (5) is installed at the opening end of the axial oil hole (304). Let L1 be the distance between the end of the plug hole where the plug (5) is installed and the oil groove (201a) of the first rocker arm. Let L2 be the distance between the end of the axial oil hole (304) and the oil groove (201b) of the second rocker arm. 5mm≤L1≤8mm, 2mm≤L2≤3mm. Let 2L3 be the axial length of the mating surface between the first rocker arm (21) and the rocker arm shaft (3). Let L4 be the width of the first annular oil groove (3010). L3=(1.8~2)L4. Let 2L5 be the axial length of the mating surface between the rocker arm seat (1) and the rocker arm shaft (3). Let L6 be the width of the third annular oil groove (3030). L5=(1.3~1.5)L6.

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