Camshaft, valve timing mechanism and engine

Abstract

The utility model relates to the technical field of engines, and provides a cam shaft. The cam shaft comprises a rotating shaft, two limiting pieces, a piston, an elastic piece and a cam. The rotating shaft is provided with an oil duct and a piston slideway communicated with the oil duct; the two limiting pieces are symmetrically arranged outside the rotating shaft in a sleeving mode and are in interference fit with the rotating shaft. The piston is movably arranged in the piston slide way and penetrates through the two limiting pieces; the two limiting pieces are sleeved with the cam, and the cam is in clearance fit with the limiting pieces. The elastic piece is arranged between the piston and the cam, and the elastic piece is in a compressed state in the initial state. The floating cam overcomes the defects that in the prior art, a cam on a cam shaft can be abraded in the long-term use process, and then normal work of an engine is affected, the floating cam is achieved, the cam has a certain floating gap, and on the basis that normal work of the cam is guaranteed, abrasion of the cam can be avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of engines, in particular to a camshaft, a valve train and an engine. Background Art

[0002] The camshaft is a key component in the valve train, which is responsible for driving the valves to open and close on time. The camshaft contacts the valve tappet during rotation through the cams thereon, thereby pushing the valves to open. When the cam rotates to the base circle part, the valves close under the action of the valve elastic member 400.

[0003] The valve train is an important part of the engine. Its main function is to open and close the intake and exhaust valves of each cylinder according to the requirements of the working cycle and firing order carried out in each cylinder of the engine, so that the fresh charge can enter the cylinder in time and the exhaust gas can be discharged from the cylinder in time.

[0004] During long-term use, the cams on the existing camshaft will rub against other parts, resulting in wear, which will affect the intake and exhaust of the engine and thus affect the normal operation of the engine. Summary of the Utility Model

[0005] The utility model provides a camshaft, a valve train and an engine to solve the defect that the cams on the existing camshaft will wear during long-term use, which will affect the normal operation of the engine, and to realize a floating cam, so that the cam has a certain floating clearance, which can avoid the wear of the cam while ensuring the normal operation of the cam.

[0006] The utility model provides a camshaft including a rotating shaft, two limiting members, a piston, an elastic member and a cam. The rotating shaft is provided with an oil passage and a piston slideway communicating with the oil passage; the two limiting members are symmetrically sleeved outside the rotating shaft, and the limiting members are in interference fit with the rotating shaft; the piston is movably arranged in the piston slideway and penetrates through the two limiting members; the cam is sleeved outside the two limiting members, and the cam is in clearance fit with the limiting members; the elastic member is arranged between the piston and the cam, and the elastic member is in a compressed state in the initial state.

[0007] According to the camshaft provided by the utility model, the oil passage is arranged along the length direction of the rotating shaft and penetrates through the rotating shaft.

[0008] According to the camshaft provided by the utility model, a rotating shaft hole is arranged inside the limiting member, and the rotating shaft penetrates through the rotating shaft hole.

[0009] According to the camshaft provided by the utility model, one end of the limiting member is provided with a limiting portion, and the other end is provided with a notch, the shape of the notch is adapted to the piston, and the piston penetrates through the notch.

[0010] According to a camshaft provided by the utility model, the piston is provided with a limiting groove, the first end of the elastic member is in contact with the limiting groove, and the second end of the elastic member is in contact with the inner wall of the cam.

[0011] According to a camshaft provided by the utility model, the elastic member is a spring.

[0012] According to a camshaft provided by the utility model, a through groove is provided inside the cam, and the limiting member is limited in the through groove.

[0013] According to a camshaft provided by the utility model, the inner wall of the through slot is provided with a groove, and the second end of the elastic member is limitedly located inside the groove.

[0014] The utility model also provides a valve train, comprising a camshaft as described in any one of the above embodiments.

[0015] The utility model also provides an engine, comprising a valve train according to any one of the above embodiments.

[0016] The utility model provides a camshaft, in which, under normal working conditions, low-pressure oil is contained in the oil passage, and the piston is always attached to the bottom of the piston slideway under the action of the elastic member. At this time, due to the existence of the upper floating space, the cam will float in the limiter as the force point changes. When the valve is in the opening stage, the top circle of the cam contacts the external parts, the upper floating space is compressed, and the elastic member is in a partially released state; when the valve is in the closing stage, the base circle of the cam contacts the external parts and the elastic member is partially compressed according to the actual situation. Due to the elastic force of the elastic member, the base circle of the cam is always in contact with the external parts, which can automatically compensate for the gap between the valve train. This automatic compensation mechanism helps to reduce the wear of the cam and improve the stability and reliability of the engine operation.

[0017] Furthermore, when the utility model enters the braking state, the oil passage is filled with high-pressure oil, and the piston compresses the elastic member outward under the action of the pressure oil. The upper floating space in the cam is replaced by the high-pressure area of ​​the piston, and the elastic member cannot adjust the cam. At this time, when the top circle of the cam contacts the external parts, the valve is in a normal open state, and when the base circle of the cam contacts the external parts, due to the existence of an extra stroke of the cam, the stroke will force the valve to open a section near the compression top dead center during the movement (under normal working conditions, the base circle at this time will not open the valve), and the compressed air will be quickly discharged from the engine cylinder through this gap, thereby reducing the power output of the engine, enhancing the braking effect, and improving the safety of the vehicle.

[0018] The present utility model further provides a gas distribution mechanism, which has the beneficial effects of the above-mentioned camshaft due to including the above-mentioned camshaft.

[0019] The present utility model further provides an engine, which also has the beneficial effects of the above-mentioned cam due to including the above-mentioned gas distribution mechanism. Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions in the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0021] Figure 1 It is one of the exploded views of the camshaft provided by the present utility model.

[0022] Figure 2 It is the second exploded view of the camshaft provided by the present utility model.

[0023] Figure 3 It is the assembly drawing of the camshaft provided by the present utility model.

[0024] Figure 4 It is the sectional view of the camshaft provided by the present utility model in the first direction under the normal working state.

[0025] Figure 5 It is the sectional view of the camshaft provided by the present utility model in the second direction under the normal working state.

[0026] Figure 6 It is the sectional view of the camshaft provided by the present utility model in the second direction under the braking working state.

[0027] Figure 7 It is the comparison diagram of the cam profiles of the camshaft provided by the present utility model under the normal working state and the braking working state.

[0028] Reference numerals: 100: rotating shaft; 200: limiting member; 300: piston; 400: elastic member; 500: cam; 600: upper floating space; 700: piston high-pressure area; 800: first base circle area; 900: second base circle area; 110: oil passage; 120: piston slideway; 210: rotating shaft hole; 220: limiting portion; 230: notch; 310: limiting groove; 510: through groove; 520: groove. Detailed Embodiments

[0029] The following further describes in detail the embodiments of the present utility model in conjunction with the accompanying drawings and embodiments. The following embodiments are used to illustrate the present utility model, but cannot be used to limit the scope of the present utility model.

[0030] In the description of the embodiments of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the embodiments of the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present utility model. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0031] In the description of the embodiments of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present utility model can be understood according to specific situations.

[0032] In the embodiments of the present utility model, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0033] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of the present utility model. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0034] In a traditional valve train, the function of the cam on the camshaft is to push the valve to open and close. Since the cams on the existing camshaft are fixedly arranged, over time, they will wear with other components, and then gaps will be generated in the valve train. These gaps will cause inaccurate opening and closing of the valve. To solve the above technical problems, the present utility model is provided. The following combines Figures 1-7 to describe the camshaft of the present utility model.

[0035] Figure 1 Figure 1 shows one of the exploded views of the camshaft provided by the embodiment of the present utility model. Figure 2 Figure 2 shows another exploded view of the camshaft provided by the embodiment of the present utility model. Figure 3 Figure 3 shows the assembly drawing of the camshaft provided by the embodiment of the present utility model. Figure 4 Figure 4 shows the sectional view of the camshaft provided by the embodiment of the present utility model in the first direction under normal working conditions.

[0036] Referring to Figures 1-4 , a camshaft provided by an embodiment of the present utility model includes a rotating shaft 100, two limiting members 200, a piston 300, an elastic member 400, and a cam 500. The rotating shaft 100 is provided with an oil passage 110 and a piston slideway 120 communicating with the oil passage 110; the two limiting members 200 are symmetrically sleeved outside the rotating shaft 100, and the limiting member 200 is in interference fit with the rotating shaft 100; the piston 300 is movably arranged in the piston slideway 120 and penetrates through the two limiting members 200; the cam 500 is sleeved outside the two limiting members 200, and the cam 500 is in clearance fit with the limiting member 200; the elastic member 400 is arranged between the piston 300 and the cam 500, and the elastic member 400 is in a compressed state in the initial state.

[0037] Figure 5 Figure 5 shows the sectional view of the camshaft 500 provided by the embodiment of the present utility model in the second direction under normal working conditions. Referring to Figure 5, in the normal working state, the oil passage 110 is filled with low-pressure oil, and the piston 300 is always in contact with the bottom of the piston slideway 120 under the action of the elastic member 400. At this time, due to the existence of the upper floating space 600, the cam 500 will float in the limiting member 200 as the force application point changes. When the valve is in the open stage, the top circle of the cam 500 contacts the external parts, and the upper floating space 600 is compressed, and the elastic member 400 is in a partially released state; when the valve is in the closed stage, the base circle of the cam 500 contacts the external parts and the elastic member 400 is partially compressed according to the actual situation. Due to the elastic force of the elastic member 400, the base circle of the cam 500 always contacts the external parts, which can automatically compensate for the clearance between the valve train. This automatic compensation mechanism helps to reduce the wear of the cam 500 and improve the smoothness and reliability of the engine operation.

[0038] Figure 6 Illustrates a second-direction sectional view of the camshaft provided by an embodiment of the present invention in the braking working state. Refer to Figure 6 , when entering the braking state, the inside of the oil passage 110 is filled with high-pressure oil, and the piston 300 compresses the elastic member 400 outward under the action of the pressure oil. The upper floating space 600 in the cam 500 is replaced by the high-pressure area 700 of the piston, and the elastic member 400 cannot adjust the cam 500. At this time, when the top circle of the cam 500 contacts the external parts, the valve is in the normal open state, and when the base circle part of the cam 500 contacts the external parts, due to the fact that the cam 500 has an additional stroke (such as Figure 7 the second base circle area 900 shown in Figure 7 illustrates a comparison diagram of the cam profiles of the camshaft provided by an embodiment of the present invention in the normal working state and the braking working state)), this stroke will force the valve to be pushed open by a certain amount near the compression top dead center during the movement process (in the normal working state, the base circle at this time will not open the valve), and the compressed air will quickly discharge from the engine cylinder through this gap, thereby reducing the power output of the engine, enhancing the braking effect, and improving the safety of the vehicle. It should be noted that Figure 7 the first base circle area 800 in Figure 7 is the location where the contour of the base circle is located in the normal working state, and

[0039] Specifically, the rotating shaft 100 has a cylindrical structure. The oil passage 110 is arranged at the center of the rotating shaft 100 along its length direction, and the oil passage 110 penetrates through the rotating shaft 100. The shape of the piston slideway 120 should be adapted to the shape of the piston 300, and the two are in clearance fit. In some possible embodiments, the piston 300 has a cuboid structure, and the corresponding piston slideway 120 is also a hole in the shape of a cuboid. The piston slideway 120 extends from one side surface of the rotating shaft 100 into its interior and is always communicated with the oil passage 110 inside the rotating shaft 100. In some possible embodiments, the bottom surface of the piston slideway 120 is flush with the center line of the oil passage 110. The diameter of the oil passage 110 is smaller than the bottom width of the piston slideway 120. Such a setting enables the bottom of the piston slideway 120 to have partial support, playing a certain limiting role on the piston 300 to prevent the piston 300 from sinking too deep and blocking the oil passage 110. To facilitate the movement of the piston 300 inside the piston slideway 120, the four edges of the piston 300 can be provided with arc chamfers. Correspondingly, the four corners of the inner wall of the piston slideway 120 are also provided with corresponding arc chamfers. The setting of the arc chamfers helps to reduce the friction between the piston 300 and the piston slideway 120, making the floating of the piston 300 smoother and more stable.

[0040] Referring to Figure 1 , in some embodiments of the present invention, a rotating shaft hole 210 is provided inside the limiting member 200, and the rotating shaft 100 penetrates through the rotating shaft hole 210. One end of the limiting member 200 is provided with a limiting portion 220, and the other end is provided with a notch 230. The shape of the notch 230 is adapted to the piston 300, and the piston 300 penetrates through the notch 230.

[0041] Specifically, the limiting member 200 can have a cuboid structure. The cross-section of the rotating shaft hole 210 is circular and is adapted to the cylindrical oil passage 110. When the cross-section of the rotating shaft hole 210 is not limited to a circle, it can also be other shapes such as a square. It only needs to be adapted to the external shape of the rotating shaft 100. During specific installation, the rotating shaft 100 can be first assembled inside the rotating shaft hole 210 of one of the limiting members 200 and penetrate through the rotating shaft hole 210. Then it should be noted that the limiting portion 220 is stuck outside the cam 500. Then, from the other side of the cam 500, another limiting member 200 needs to be assembled so that the two limiting members 200 are symmetrically arranged, and at the same time, the limiting portion 220 of the other limiting member 200 is also stuck outside the other side of the cam 500 (as Figure 2 shown). The notch 230 extends from one end of the limiting member 200 to the other end direction, thus forming a notch on the top surface of the limiting member 200, and the notch 230 is communicated with the rotating shaft hole 210.

[0042] In the above structure, the shaft hole 210 provided inside the stopper 200 ensures that the shaft 100 can be accurately and stably passed through it, reducing the mechanical wear and performance degradation caused by the shaking or deviation of the shaft 100. The interference fit between the stopper 200 and the shaft 100 further enhances the stability of the connection and prevents the shaft 100 from loosening or falling off under high-speed rotation or high-load conditions. The shape of the notch 230 at one end of the stopper 200 is adapted to the piston 300, so that the piston 300 can smoothly pass through the notch 230 and move freely in the slideway of the piston 300. This design reduces the resistance and friction when the piston 300 moves, and improves the response speed and efficiency of the system. The utility model cleverly combines the components such as the shaft 100, the stopper 200 and the piston 300 together, so that the entire camshaft system has a compact structure and a high degree of integration. This not only reduces the volume and weight of the system, but also helps to improve the overall layout rationality and space utilization of the engine.

[0043] In some possible embodiments, the shape of the notch 230 is finely designed according to the specific shape and size of the piston 300. For example, a circular arc transition or chamfering process can be used to reduce the friction and wear between the piston 300 and the edge of the notch 230. At the same time, the size range of the notch 230 is reasonably determined to ensure that the piston 300 can pass smoothly without shaking due to an excessively large gap.

[0044] Reference Figure 1 In some embodiments of the present invention, the piston 300 is provided with a limiting groove 310, the first end of the elastic member 400 is in contact with the limiting groove 310, and the second end of the elastic member 400 is in contact with the inner wall of the cam 500. Specifically, the elastic member 400 may be a spring.

[0045] In the above structure. The spring, as an elastic member 400, plays a good buffering role between the piston 300 and the cam 500. When the piston 300 reciprocates in the cylinder, due to the change of gas pressure in the cylinder and the inertia of mechanical parts, a large impact force and vibration will be generated. The spring can absorb these impact energies, reduce vibration transmission, protect mechanical parts from damage, and extend service life. Secondly, the elastic force of the spring enables the piston 300 and the cam 500 to maintain stable contact, and even in the case of high-speed operation or load changes, it can ensure effective contact between the two, avoid problems such as air leakage and oil leakage caused by excessive gaps, and improve mechanical efficiency. In this embodiment, due to the elasticity of the spring, it can automatically adjust according to the actual gap between the piston 300 and the cam 500 to ensure that the best matching state can be maintained under different working conditions. This adaptive ability helps to reduce mechanical failures caused by gap changes and improve the reliability and stability of the system.

[0046] Reference Figure 1, in some embodiments of the present utility model, a through groove 510 is provided inside the cam 500, and the limiting member 200 is limited in the through groove 510. A groove 520 is provided on the inner wall of the through groove 510, and the second end of the elastic member 400 is limited inside the groove 520. Specifically, the cross-section of the through groove 510 is rectangular and is adapted to the outer contour of the limiting member 200.

[0047] In the above structure, the design of the groove 520 provides an accurate positioning and fixing point for the second end of the elastic member 400. This design ensures that the elastic member 400 will not move or fall off randomly when subjected to pressure or vibration, thus maintaining a stable connection relationship between the piston and the cam 500. The tight fit between the groove 520 and the elastic member 400 not only improves the stability of the connection, but also enhances the overall strength of the cam 500 structure. This design helps to resist external impacts and vibrations and reduces failures caused by structural loosening or damage.

[0048] The present utility model also provides a valve train, including a camshaft as in any one of the above embodiments.

[0049] The present utility model also provides an engine, including the valve train as in any one of the above embodiments.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present utility model and are not intended to limit them; although the present utility model has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present utility model.

Claims

1. A camshaft, characterized in that: include: A rotating shaft (100) is provided with an oil passage (110) and a piston slideway (120) connected to the oil passage (110); Two limiting members (200) are symmetrically sleeved on the outside of the rotating shaft (100), and the limiting members (200) and the rotating shaft (100) are interference fit; A piston (300) movably disposed in the piston slideway (120) and passing through the two stoppers (200); A cam (500) is sleeved on the outside of the two limiting members (200), and the cam (500) and the limiting members (200) are clearance-matched; An elastic member (400) is provided between the piston (300) and the cam (500); the elastic member (400) is in a compressed state in an initial state.

2. The camshaft according to claim 1, characterized in that The oil channel (110) is arranged along the length direction of the rotating shaft (100) and passes through the rotating shaft (100).

3. The camshaft according to claim 1, characterized in that: A rotating shaft hole (210) is provided inside the limiting member (200), and the rotating shaft (100) passes through the rotating shaft hole (210).

4. The camshaft according to claim 3, characterized in that: A limiting portion (220) is provided at one end of the limiting member (200), and a notch (230) is provided at the other end; the shape of the notch (230) is adapted to the piston (300), and the piston (300) passes through the notch (230).

5. The camshaft according to claim 1, characterized in that: The piston (300) is provided with a limiting groove (310), the first end of the elastic member (400) is in contact with the limiting groove (310), and the second end of the elastic member (400) is in contact with the inner wall of the cam (500).

6. The camshaft according to claim 5, characterized in that The elastic member (400) is a spring.

7. The camshaft according to claim 5, characterized in that A through slot (510) is provided inside the cam (500), and the limiting member (200) is limited in the through slot (510).

8. The camshaft according to claim 7, characterized in that The inner wall of the through slot (510) is provided with a groove (520), and the second end of the elastic member (400) is located inside the groove (520).

9. A valve train, characterized in that: Comprising a camshaft as claimed in any one of claims 1 to 8.

10. An engine, characterized in that: Comprising the valve train as claimed in claim 9.

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