A variable timing cam follower, a valve group and an engine equipped with the same

Abstract

The present invention relates to a variable timing cam follower and a valve group and an engine provided with the same, and belongs to the technical field of variable valve timing. The cam follower includes a follower body, the follower body is arranged between a tappet and a camshaft, the follower body moves between the tappet and the camshaft, a side of the follower body close to the camshaft slides on the cam surface of the camshaft, a curved track is arranged on a side of the follower close to the tappet, the tappet slides on the curved track, and the position between the tappet and the camshaft axis remains unchanged. The valve group includes the above-mentioned variable timing cam follower, and also includes a tappet and a rocker arm valve group. The engine also includes a camshaft, and a side of the follower body close to the camshaft slides on the cam surface of the camshaft. The present invention can adjust the valve timing of the engine, and the valve clearance remains unchanged during the valve timing adjustment process, thereby ensuring the reliability and stability of the engine during operation.

Description

Technical Field

[0001] The invention belongs to the technical field of variable valve timing, and relates to a variable timing cam follower and a valve group and an engine provided with the same. Background Art

[0002] The application market has higher and higher requirements for performance under different working conditions, while emission regulations have increasingly stricter requirements for engine emissions. In order to adapt the engine to market demand and meet regulatory requirements, mainstream engine design and manufacturing companies have successively launched high-power engines including variable valve technology.

[0003] like Figure 1 As shown, currently, the engine valve timing is usually adjusted by using the engine cam follower. When the engine is running normally, the camshaft 1 rotates, and the camshaft 1 drives the tappet 5 to move in the lift direction through the follower body 2. The tappet 5 realizes the opening and closing of the valve 11 through the push rod 7, the rocker arm 8, the valve bridge 9 and the spring 10. When adjusting the valve timing, as shown in FIG. Figure 2 As shown, the eccentric shaft group 6 takes point O as the rotation center, driving the follower to move from a0 to a1. When the roller 3 is driven by the follower to move from b0 to b1, the contact point of the push rod 7 also moves from c0 to c1. After the valve timing is adjusted, the valve opening angle changes from angle α to angle β, and the valve timing changes by β-α. The position of the cam follower in the lift direction of the push rod changes by Δ, causing the contact point height of the push rod 7 to change by Δ2. This will cause the valve clearance to change by Δ1. The change in valve clearance affects the reliability and stability of the engine during operation. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a variable timing cam follower and a valve group and an engine equipped with the same, which can adjust the valve timing of the engine. The valve clearance remains unchanged during the valve timing adjustment process, thereby ensuring the reliability and stability of the engine during operation.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A variable timing cam follower comprises a follower body, wherein the follower body is arranged between a tappet and a camshaft, the follower body moves between the tappet and the camshaft, a side of the follower body close to the camshaft slides on the cam surface of the camshaft, a curved track is arranged on a side of the follower close to the tappet, the tappet slides on the curved track, and the position between the tappet and the camshaft axis remains unchanged.

[0007] Optionally, the curved track is arranged along the movement direction of the follower body.

[0008] Optionally, a roller is provided on the side of the follower body that cooperates with the camshaft, and the follower body slides on the cam surface of the camshaft through the roller.

[0009] Optionally, the curved track is arranged on one end of the follower body, and an eccentric rotating shaft is arranged on the other end of the follower body. The eccentric rotating shaft is rotatably connected to the eccentric end of the eccentric shaft group, and the eccentric shaft group drives the follower body to move between the tappet and the camshaft.

[0010] A valve group provided with a variable timing cam follower includes the above-mentioned variable timing cam follower, and also includes a tappet and a rocker arm valve group, one end of the tappet is connected to the rocker arm valve group, and the other end of the tappet slides on the curved track of the variable timing cam follower.

[0011] Optionally, a roller is provided on one end of the tappet close to the curved track, and the tappet slides on the curved track via the roller.

[0012] An engine provided with a variable timing cam follower includes the above-mentioned variable timing cam follower, and also includes a tappet and a camshaft. The variable timing cam follower is arranged between the tappet and the camshaft, and the end of the tappet close to the camshaft slides on a curved track, and the side of the follower body close to the camshaft slides on the cam surface of the camshaft.

[0013] The beneficial effects of the present invention are as follows: (1) A curved track is provided on the side of the follower close to the tappet. When the valve timing is adjusted, the follower body slides relative to the tappet, and the tappet slides on the curved track. The curved track absorbs the displacement of the follower body in the lift direction of the tappet, so that the position between the tappet and the camshaft axis remains unchanged, thereby keeping the valve clearance of the engine unchanged during the valve timing adjustment process. (2) A roller is provided on the side of the follower body that cooperates with the camshaft, and a roller is provided on the end of the tappet that cooperates with the follower body. The roller and the roller can reduce the friction of the follower body when it moves between the camshaft and the tappet, reduce the wear between the camshaft, the follower body and the tappet, and make the valve timing adjustment more sensitive.

[0014] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0016] Figure 1 is a schematic diagram of the structure of a traditional cam follower;

[0017] Figure 2 A schematic diagram of the process of adjusting valve timing for a conventional cam follower;

[0018] Figure 3 Schematic diagram of the structure of the cam follower in this embodiment;

[0019] Figure 4 It is a schematic diagram of the process of the cam follower adjusting the valve timing in this embodiment.

[0020] Figure numerals: camshaft 1, follower body 2, roller 3, roller 4, tappet 5, eccentric rotating shaft 6, push rod 7, rocker arm 8, valve bridge 9, spring 10, valve 11, eccentric shaft group 12, curved track 21. DETAILED DESCRIPTION

[0021] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0022] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0023] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0024] See also Figure 3 , is a valve group provided with a variable timing cam follower, including a variable timing cam follower, a tappet 5 and a rocker valve group. The variable timing cam follower includes a follower body 2, the follower body 2 is arranged between the tappet 5 and the camshaft 1, and a curved track 21 is arranged on the side of the follower close to the tappet 5. One end of the tappet 5 is connected to the rocker valve group, and the other end of the tappet 5 acts on the curved track 21 of the follower body 2. The follower body 2 moves between the tappet 5 and the camshaft 1, and the curved track 21 is arranged along the movement direction of the follower body 2. The side of the follower body 2 close to the camshaft 1 slides on the cam surface of the camshaft 1, and the tappet 5 slides on the curved track 21, and the curved track 21 keeps the position between the tappet 5 and the axis of the camshaft 1 unchanged.

[0025] In this embodiment, a roller 4 is provided on one end of the tappet 5 close to the curved track 21, and a roller 3 is provided on the side of the follower body 2 that cooperates with the camshaft 1, and the follower body 2 slides on the cam surface of the camshaft 1 through the roller 3. The tappet 5 slides on the curved track 21 through the roller 4. In this embodiment, an eccentric shaft 6 is provided on one end of the follower body 2 away from the curved track 21, and the follower body 2 is rotatably connected to the eccentric end of the eccentric shaft group 12 through the eccentric shaft 6. When the valve timing is adjusted, the eccentric shaft group 12 drives the follower body 2 to move between the tappet 5 and the camshaft 1. A roller 3 is provided on one side of the follower body 2 which cooperates with the camshaft 1, and a roller 4 is provided on one end of the tappet 5 which cooperates with the follower body 2. The roller 4 and the roller 3 can reduce the friction of the follower body 2 when it moves between the camshaft 1 and the tappet 5, reduce the wear between the camshaft 1, the follower body 2 and the tappet 5, and make the valve timing adjustment more sensitive.

[0026] The curved track 21 is a fitting curved surface, and the trajectory of the fitting curved surface is the motion trajectory of the tappet 5 relative to the axis of the roller 4 when the eccentric shaft group 12 rotates. During the fitting process of the curved track 21, the positions of the axis O1 of the eccentric shaft group 12, the axis O2 of the camshaft 1, and the tappet 5 remain unchanged. When the eccentric shaft group 12 rotates a certain angle, the eccentric shaft group 12 drives the roller 4 of the follower body 2 to slide on the cam surface of the camshaft 1. Since the profile of the cam surface is known, and the relative position between the eccentric rotating shaft 6 and the axis of the roller 4 is known, the position of the axis of the roller 4 when the eccentric shaft group 12 rotates a certain angle can be obtained, and since the position of the tappet 5 remains unchanged, the position of the tappet 5 relative to the axis of the roller 4 can be obtained. The eccentric shaft group 12 rotates several angles in sequence to obtain the motion trajectory of the tappet 5 relative to the axis of the roller 4, which is the trajectory of the curved track 21.

[0027] See also Figure 4When the valve timing is actually adjusted, the eccentric shaft group 12 rotates by an angle γ. During the rotation of the eccentric shaft group 12, the axis positions of the eccentric shaft 6 are A0, A1, and A2 in sequence. The eccentric shaft group 12 drives the follower body 2 to move between the tappet 5 and the camshaft 1, and the roller 3 rolls against the cam surface of the camshaft 1, so that the phase angle of the valve timing is adjusted by θ. During the rolling of the roller 3, the axis of the roller 3 is F0, F1, and F2 in sequence, and the displacement of the axis of the roller 3 in the lift direction of the tappet 5 is Δ. The roller 4 on the tappet 5 slides on the curved track 21, and the contact points between the roller 4 and the curved track 21 are G0, G1, and G2 in sequence. Since the curved track 21 is a fitting curved surface, the curved track 21 absorbs the displacement of the follower body 2 in the lift direction, so that the relative position between the tappet 5 and the axis of the camshaft 1 remains unchanged, and the distance between the axis of the roller 4 and the axis of the camshaft 1 in the lift direction of the tappet 5 is always H, thereby ensuring that the valve clearance Δ1 of the engine remains unchanged during the valve timing adjustment process.

[0028] At the same time, the tappet 5 is slidably connected to the curved track 21. When the valve timing is adjusted, the tappet 5 will not move with the follower body 2, which reduces the swing range of the tappet 5 and the push rod 7, and further reduces the size of the push rod sealing sleeve, which is beneficial to the simplification of the engine structure and size.

[0029] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A variable timing cam follower, comprising a follower body, wherein the follower body is arranged between a tappet and a camshaft, and wherein: The follower body moves between the tappet and the camshaft, and the side of the follower body close to the camshaft slides on the cam surface of the camshaft. A curved track is provided on the side of the follower body close to the tappet. One end of the tappet is connected to the rocker arm valve group, and the other end of the tappet slides on the curved track of the variable timing cam follower. The curved track is a fitting curved surface. During the valve timing adjustment process, the curved track absorbs the displacement of the follower body in the lift direction, the position between the tappet and the camshaft axis remains unchanged, and the engine valve clearance remains unchanged.

2. A variable timing cam follower according to claim 1, characterized in that: The curved track is arranged along the moving direction of the follower body.

3. The variable timing cam follower according to claim 1, characterized in that: A roller is arranged on one side of the follower body that cooperates with the camshaft, and the follower body slides on the cam surface of the camshaft through the roller.

4. The variable timing cam follower according to claim 1, characterized in that: The curved track is arranged on one end of the follower body, and an eccentric rotating shaft is arranged on the other end of the follower body. The eccentric rotating shaft is rotatably connected to the eccentric end of the eccentric shaft group, and the eccentric shaft group drives the follower body to move between the tappet and the camshaft.

5. A valve train with a variable timing cam follower, characterized in that: It comprises a variable timing cam follower as described in any one of claims 1 to 4, and also comprises a tappet and a rocker arm valve group, one end of the tappet is connected to the rocker arm valve group, and the other end of the tappet slides on the curved track of the variable timing cam follower.

6. A valve train with a variable timing cam follower according to claim 5, characterized in that: A roller is arranged on one end of the tappet close to the curved track, and the tappet slides on the curved track via the roller.

7. An engine provided with a variable timing cam follower, characterized in that: It includes a variable timing cam follower as described in any one of claims 1 to 4, and also includes a tappet and a camshaft, the variable timing cam follower is arranged between the tappet and the camshaft, the end of the tappet close to the camshaft slides on a curved track, and the side of the follower body close to the camshaft slides on the cam surface of the camshaft.

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