intermediate rocker arm, variable valve lift system and assembly method

Abstract

This invention relates to an intermediate rocker arm for a valve mechanism, a variable valve lift system, and an assembly method. The intermediate rocker arm includes a rocker arm housing having a pivot hole extending laterally. The pivot hole is used to support the intermediate rocker arm on a cylindrical support structure, allowing the intermediate rocker arm to rotate around the support structure within a predetermined angle range. The pivot hole is an open hole with a circumferential notch, allowing the support structure to be installed into the pivot hole along a longitudinal plane perpendicular to the lateral direction from the notch portion of the pivot hole. The intermediate rocker arm, variable valve lift system, and assembly method of this invention are easy to assemble.

Description

Technical Field

[0001] This invention relates to the field of engine technology. Specifically, this invention relates to an intermediate rocker arm for a valve mechanism, a variable valve lift system including such an intermediate rocker arm, and an assembly method for such a variable valve lift system. Background Technology

[0002] In existing vehicle internal combustion engines, a valve system is generally provided, and therefore a rocker arm device is provided to convert the rotational motion of the cam into the linear motion of the valve pushrod. In order to obtain a continuously variable valve lift (VVL), a common rocker arm device usually includes a valve rocker arm for driving the valve pushrod and an intermediate rocker arm for pushing the valve rocker arm.

[0003] For example, CN 104712395 A discloses a typical variable valve lift device, which includes a valve pushrod, a valve rocker arm, an intermediate rocker arm, and a cam mechanism. The cam mechanism rotates to drive the intermediate rocker arm to swing, which in turn pushes the valve rocker arm to control valve opening and closing. In this conventional design, the intermediate rocker arm housing is rotatably supported in the engine by a mounting pin. The mounting pin is generally cylindrical and is mounted on other support structures in the engine. One end of the rocker arm housing has a transversely through mounting hole through which the mounting pin passes, allowing the rocker arm housing to swing around the mounting pin.

[0004] However, this type of intermediate rocker arm requires high precision in the fit between the mounting holes and the support structure, and the mounting pins need to pass through the mounting holes on the two side plates of the rocker arm housing sequentially. This installation process is quite complex, requiring a separate workstation for assembly, after which the assembled support structure and intermediate rocker arm are installed above the valve rocker arm in the engine. This installation method increases both the scrap rate and the difficulty of the assembly process. Therefore, the traditional production process of intermediate rocker arms is cumbersome and costly. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to provide an easy-to-assemble intermediate rocker arm, a variable valve lift system, and an assembly method.

[0006] The aforementioned technical problem is solved by an intermediate rocker arm for a valve mechanism according to the present invention. The intermediate rocker arm includes a rocker arm housing having a pivot hole extending laterally, the pivot hole for support on a cylindrical support structure, allowing the intermediate rocker arm to rotate around the support structure within a predetermined angle range. The pivot hole is an open hole with a notch in the circumferential direction, allowing the support structure to be mounted into the pivot hole along a longitudinal plane perpendicular to the lateral direction from the notch portion of the pivot hole. Therefore, the process of mounting the intermediate rocker arm onto the support structure is simplified, and the intermediate rocker arm can be conveniently mounted after the support structure has been installed in the engine.

[0007] According to a preferred embodiment of the present invention, the intermediate rocker arm may have a first contact portion for abutting the drive mechanism and a second contact portion for abutting the valve rocker arm. Viewed in a longitudinal plane, the first contact portion, the second contact portion, and the pivot hole may be triangularly distributed. Therefore, the intermediate rocker arm can be positioned in the longitudinal plane by a three-point support, without requiring a fully circular pivot hole surrounding the support structure for positioning. Preferably, the intermediate rocker arm may include a roller for abutting the drive mechanism, the roller being rotatably mounted on the rocker arm housing. The first contact portion may be the area on the roller that abuts the drive mechanism in real time, while the rocker arm housing may have a drive contact surface for abutting the valve rocker arm, and the second contact portion may be the area on the drive contact surface that abuts the valve rocker arm in real time.

[0008] According to another preferred embodiment of the present invention, viewed in a longitudinal plane, within the rotation range of the intermediate rocker arm, the opening direction of the pivot hole can always be opposite to the line connecting the first contact portion and the second contact portion. Therefore, during the rotation of the intermediate rocker arm, the support structure, the drive mechanism, and the valve rocker arm can always stably clamp the intermediate rocker arm, thereby preventing the intermediate rocker arm from falling off. More preferably, viewed in a longitudinal plane, within the rotation range of the intermediate rocker arm, the angle between the notch chord of the pivot hole and the line connecting the first contact portion and the second contact portion can always be less than a predetermined threshold.

[0009] According to another preferred embodiment of the invention, when viewed in a longitudinal plane, the pivot hole can have an arcuate profile, and in particular, the arcuate profile of the pivot hole can match the profile of the support structure, thereby facilitating the rotation of the intermediate rocker arm around the support structure.

[0010] According to another preferred embodiment of the invention, the central angle corresponding to the circumferential extension of the pivot hole can be equal to or less than 180 degrees, so as to ensure that the intermediate rocker arm can be easily mounted on the support structure. More preferably, the central angle corresponding to the circumferential extension of the pivot hole can be in the range of 150 degrees to 180 degrees, thereby reducing the risk of the intermediate rocker arm falling off the support structure.

[0011] According to another preferred embodiment of the invention, the rocker arm housing may have two side plates spaced apart in the lateral direction and two pivot holes formed on the two side plates respectively, the two pivot holes being aligned in the lateral direction and having the same shape and opening direction.

[0012] The aforementioned technical problems are further solved by a variable valve lift system according to the present invention. This variable valve lift system includes a valve rocker arm, a drive mechanism, and a support structure. The system further includes an intermediate rocker arm having the aforementioned features.

[0013] The aforementioned technical problem is further solved by an assembly method for the aforementioned variable valve lift system according to the present invention. This assembly method includes: after installing the valve rocker arm and support structure in place, installing an intermediate rocker arm on the support structure, and simultaneously installing the drive mechanism, such that the intermediate rocker arm is supported between the valve rocker arm, the support structure, and the drive mechanism. Therefore, the assembly of the intermediate rocker arm, the support structure, and the drive mechanism can be performed simultaneously at one workstation, thereby simplifying the assembly process. Attached Figure Description

[0014] The invention is further described below with reference to the accompanying drawings. In the drawings, the same reference numerals represent elements with the same function. Wherein:

[0015] Figure 1 A schematic diagram showing the installation state of the intermediate rocker arm in a variable valve lift system according to an embodiment of the present invention; and

[0016] Figure 2 A perspective view of the intermediate rocker arm according to an embodiment of the present invention is shown. Detailed Implementation

[0017] The following describes specific embodiments of the intermediate rocker arm, variable valve lift system, and assembly method according to the present invention, with reference to the accompanying drawings. The detailed description and drawings below are provided to exemplify the principles of the invention; the invention is not limited to the described preferred embodiments, and the scope of protection of the invention is defined by the claims.

[0018] According to an embodiment of the present invention, an intermediate rocker arm for a valve mechanism is provided. This intermediate rocker arm is installed in a variable valve lift system to drive the valve rocker arm to rotate in order to control the valve lift.

[0019] Figures 1 to 2 A schematic embodiment of the intermediate rocker arm according to the present invention is shown. Figure 1 As shown, the intermediate rocker arm 30 is installed in the variable valve lift system. The variable valve lift system mainly includes the valve rocker arm 10, the drive mechanism 20, the intermediate rocker arm 30, and the support structure 40. Figure 1The plane shown is defined by two orthogonal dimensions of the valve rocker arm 10 and the intermediate rocker arm 30, which have larger dimensions. It is called the longitudinal plane, and the direction perpendicular to the longitudinal plane is called the lateral direction.

[0020] One end of the valve rocker arm 10 is supported on a hydraulic clearance adjuster (not shown), and the other end abuts against the valve push rod (not shown), and can be fulcrumd with the hydraulic clearance adjuster as a pivot point. Figure 1 Rotate in the longitudinal plane shown.

[0021] The support structure 40 is generally cylindrical, with its central axis extending approximately in the transverse direction. The support structure 40 can be fixed to a structure such as an engine cylinder head; it can be a pin mounted on another housing structure or an integral part of another housing structure. The intermediate rocker arm 30 is rotatably mounted on the support structure 40 and simultaneously abuts against the valve rocker arm 10 and the drive mechanism 20.

[0022] The drive mechanism 20 can be, for example, a cam drive mechanism consisting of a camshaft and rollers. The drive mechanism 20 can drive the intermediate rocker arm 30 to rotate in the direction of compressing the valve rocker arm 10 (in...). Figure 1 (The middle rocker arm 30 rotates downwards in a clockwise direction), which in turn drives the valve rocker arm 10 to rotate downwards around the top of the hydraulic clearance adjuster.

[0023] Furthermore, the variable valve lift system may also include a reset member 50. The reset member 50 may be, for example, a torsion spring. The reset member 50 abuts against the intermediate rocker arm 30 and is capable of providing a restoring force to the intermediate rocker arm 30 opposite to the driving force of the drive mechanism 20, so that when the drive mechanism 20 does not provide a driving force, the intermediate rocker arm 30 can automatically rotate in a direction away from the valve rocker arm 10 (in...). Figure 1 (The intermediate rocker arm 10 rotates counterclockwise upwards), thereby allowing the valve rocker arm 10 to lift. During operation of the variable valve lift system, the rotation of the valve rocker arm 10 and the intermediate rocker arm 30 in the longitudinal plane is limited to a predetermined angle range, which can be defined by the drive range of the drive mechanism 20.

[0024] Figure 2 It shows Figure 1 A three-dimensional view of the middle rocker arm 30. (See diagram below.) Figure 2 As shown, the intermediate rocker arm 30 includes a rocker arm housing 31, a roller 32, and a pivot pin 33. The roller 32 is rotatably mounted on the rocker arm housing 31 via the pivot pin 33. When the intermediate rocker arm 30 is mounted... Figure 1 In the variable valve lift system shown, the central axis of the pivot pin 33 is approximately parallel to the lateral direction, allowing the roller 32 to rotate around the pivot pin 33 in the longitudinal plane.

[0025] Specifically, the rocker arm housing 31 may have two parallel extending side plates 311. The extending direction of the side plates 311 is approximately perpendicular to the central axis of the pivot pin 33, so that when the intermediate rocker arm 30 is installed in a variable valve lift system, the extending direction of the side plates 311 is approximately parallel to the longitudinal plane. The two side plates 311 are spaced apart in the lateral direction, and rollers 32 may be installed between the two side plates 311.

[0026] like Figure 1 As shown, roller 32 is used to abut against drive mechanism 20. At any given time, the area on the outer peripheral surface of roller 32 that actually abuts against drive mechanism 20 can be called the first contact portion P1. The first contact portion P1 is a dynamic area on the surface of roller 32 that changes with the rotational position of intermediate rocker arm 30, and since roller 32 and drive mechanism 20 are usually in tangential contact, ideally, when viewed in the longitudinal plane, this area can be approximated as a dynamic point.

[0027] The two side plates 311 can be connected together at one end near the valve rocker arm 10 via a laterally extending end plate. The side of this end plate facing the valve rocker arm 10 forms a drive contact surface 312 for abutting against the valve rocker arm 10. The drive contact surface 312 has a second contact portion P2 that abuts against the valve rocker arm 10 in real time. Similar to the first contact portion P1, the second contact portion P2 is also a dynamic region on the drive contact surface 312 that changes with the rotational position of the intermediate rocker arm 30, and ideally, when viewed in the longitudinal plane, this region can also be approximated as a dynamic point.

[0028] Each side plate 311 has a pivot hole 313 formed at the end away from the valve rocker arm 10. The pivot hole 313 extends through the corresponding side plate 311 in the lateral direction. Preferably, the pivot holes 313 on the two side plates 311 have the same shape and size and are aligned in the lateral direction, so that the two pivot holes 313 can completely overlap when viewed in the lateral direction. The following description uses only one pivot hole 313 as an example to illustrate this embodiment.

[0029] Unlike existing technologies, in embodiments according to the present invention, the pivot hole 313, when viewed in the longitudinal plane, is not a closed, complete hole, but an open hole with a notch in the circumferential direction. The opening directions of the pivot holes 313 on the two side plates 311 are also preferably identical. The pivot hole 313 can be formed as a hole with an arcuate profile in the longitudinal plane, particularly as a portion of a circle. The cylindrical support structure 40 can be directly installed into the pivot hole 313 along the longitudinal plane from the notch portion. Therefore, the assembly process between the intermediate rocker arm 30 and the support structure 40 can be completed very easily without the need for additional installation tools.

[0030] Preferably, the central angle corresponding to the circumferential extension of the pivot hole 313 is equal to or less than 180 degrees; that is, the pivot hole 313 can be formed as a semicircle or smaller. This facilitates the unobstructed insertion of the support structure 40 into the pivot hole 313 along the longitudinal plane. However, to prevent the intermediate rocker arm 30 from detaching from the support mechanism 40, the notch portion of the pivot hole 313 cannot be too large. Preferably, the central angle corresponding to the circumferential extension of the pivot hole 313 can be in the range of 150 degrees to 180 degrees (inclusive).

[0031] To prevent the support structure 40 from sliding out of the pivot hole 313 during the rotation of the intermediate rocker arm 30, the valve rocker arm 10, the drive mechanism 20, and the support structure 40 can form a triangular support arrangement for the intermediate rocker arm 30 in the longitudinal plane. Specifically, as Figure 1 As shown, when viewed in the longitudinal plane, the pivot hole 313, the first contact part P1 and the second contact part P2 are arranged in a triangle, which makes the intermediate rocker arm 30 constrained between the valve rocker arm 10, the drive mechanism 20 and the support structure 40 and unable to move freely along the longitudinal plane.

[0032] In the above scenario, viewed in the longitudinal plane, throughout the entire rotation range of the intermediate rocker arm 30, the opening direction of the pivot hole 313 always faces away from the line connecting the first contact portion P1 and the second contact portion P2. Specifically, within the rotation range of the intermediate rocker arm 30, the angle between the notch chord of the pivot hole 313 (i.e., the line connecting the arcuate endpoints of the pivot hole 313) and the line connecting the first contact portion P1 and the second contact portion P2 is preferably always less than a predetermined threshold. This ensures that the resultant force of the supporting forces of the valve rocker arm 10 and the drive mechanism 20 on the intermediate rocker arm 30 is always approximately directed towards the notch direction of the pivot hole 313, thereby preventing the support structure 40 from slipping out of the notch portion.

[0033] Furthermore, viewed in the longitudinal plane, the pivot hole 313 preferably has an arcuate profile that matches the support structure 40. Since the pivot hole 313 is an open partial hole, it only needs to maintain a tangential contact with the support structure 40 during rotation. This means that the matching arcuate profile does not need to have the exact same radius as the support structure 40, but can have a larger radius. This reduces the precision requirements for the machining and assembly of the intermediate rocker arm 30, thereby reducing production costs.

[0034] According to another embodiment of the invention, a variable valve lift system for an engine of a motor vehicle is also provided, which includes an intermediate rocker arm 30 according to the foregoing embodiment, and thus has the corresponding features and advantages of the intermediate rocker arm. Furthermore, the variable valve lift system may also include a valve rocker arm 10, a drive mechanism 20, and a support structure 40 according to the foregoing embodiment, as well as other possible components.

[0035] According to another embodiment of the present invention, an assembly method for a variable valve lift system according to the foregoing embodiments is also provided. In this assembly method, the valve rocker arm 10 and the support structure 40 can be installed in one assembly station first. After the valve rocker arm 10 and the support structure 40 are installed, the intermediate rocker arm 30 can be installed on the support structure 40, and the drive mechanism 20 can be installed simultaneously, such that the intermediate rocker arm 30 is supported between the valve rocker arm 10, the drive mechanism 20, and the support structure 40. Since the support structure 40 can be directly inserted into the pivot hole 313 along the longitudinal plane through the notch portion of the pivot hole 313, a separate station is not required to complete the assembly between the intermediate rocker arm 30 and the support structure 40. In addition, the assembly of the drive mechanism 20 can be completed simultaneously. This assembly method significantly simplifies the installation process, thereby effectively reducing production costs.

[0036] While possible embodiments have been described exemplarily in the foregoing description, it should be understood that numerous variations of embodiments exist through combinations of all known and readily conceived technical features and implementation methods. Furthermore, it should be understood that the exemplary embodiments are merely examples and do not in any way limit the scope, application, or construction of the invention. The foregoing description is more intended to provide those skilled in the art with technical guidance for transforming at least one exemplary embodiment, wherein various changes, particularly regarding the function and structure of the components, can be made without departing from the scope of the claims.

[0037] Appendix Label Table

[0038] 10 Valve rocker arm

[0039] 20 Drive mechanism

[0040] 30 center rocker arm

[0041] 31 Rocker arm housing

[0042] 311 Side Panel

[0043] 312 Drive contact surface

[0044] 313 Pivot Hole

[0045] 32 Rollers

[0046] 33 Pivot pin

[0047] 40 Supporting Structure

[0048] 50 Reset components

[0049] P1 First Contact Section

[0050] P2 Second Contact Section

Claims

1. An intermediate rocker arm (30) for a valve mechanism, comprising a rocker arm housing (31) having a pivot hole (313) extending laterally, the pivot hole (313) for supporting on a cylindrical support structure (40), such that the intermediate rocker arm (30) can rotate around the support structure (40) within a predetermined angle range, the intermediate rocker arm (30) having a first contact portion (P1) for abutting a drive mechanism (20) and for abutting a valve. The second contact portion (P2) of the rocker arm (10) and the third contact portion (P3) for abutting the torsion spring support leg of the reset member (50), the reset member (50) providing a restoring force to the intermediate rocker arm (30) opposite to the driving force of the drive mechanism (20), the intermediate rocker arm (30) being supported between the valve rocker arm (10), the support structure (40), the torsion spring support leg of the reset member (50) and the drive mechanism (20) while rotating around the support structure (40). Its features are, The pivot hole (313) is an open hole with a notch in the circumferential direction, so that the support structure (40) can be installed into the pivot hole (313) from the notch portion of the pivot hole (313) along a longitudinal plane perpendicular to the transverse direction.

2. The intermediate rocker arm (30) according to claim 1, characterized in that When viewed in the longitudinal plane, the first contact portion (P1), the second contact portion (P2), and the pivot hole (313) are arranged in a triangular pattern.

3. The intermediate rocker arm (30) according to claim 2, characterized in that Viewed in the longitudinal plane, within the rotation range of the intermediate rocker arm (30), the opening direction of the pivot hole (313) is always opposite to the line connecting the first contact portion (P1) and the second contact portion (P2).

4. The intermediate rocker arm (30) according to claim 3, characterized in that, When viewed in the longitudinal plane, within the rotation range of the intermediate rocker arm (30), the angle of the notch chord of the pivot hole (313) relative to the line connecting the first contact portion (P1) and the second contact portion (P2) is always less than a predetermined threshold.

5. The intermediate rocker arm (30) according to claim 1, characterized in that, When viewed in the longitudinal plane, the pivot hole (313) has an arcuate profile.

6. The intermediate rocker arm (30) according to claim 5, characterized in that, The central angle corresponding to the circumferential extension range of the pivot hole (313) is equal to or less than 180 degrees.

7. The intermediate rocker arm (30) according to claim 6, characterized in that, The central angle corresponding to the circumferential extension range of the pivot hole (313) is in the range of 150 degrees to 180 degrees.

8. The intermediate rocker arm (30) according to any one of claims 1 to 7, characterized in that, The rocker arm housing (31) has two side plates (311) spaced apart along the lateral direction and two pivot holes (313) formed on the two side plates (311), the two pivot holes (313) being aligned along the lateral direction and having the same shape and opening direction.

9. A variable valve lift system, comprising a valve rocker arm (10), a drive mechanism (20), and a support structure (40), characterized in that, The variable valve lift system further includes an intermediate rocker arm (30) according to any one of claims 1 to 8.

10. A method for assembling a variable valve lift system according to claim 9, characterized in that, The assembly method includes: After the valve rocker arm (10) and the support structure (40) are installed in place, the intermediate rocker arm (30) is installed on the support structure (40), and the drive mechanism (20) is installed in place, so that the intermediate rocker arm (30) is supported between the valve rocker arm (10), the support structure (40) and the drive mechanism (20).

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