Valve rocker arm assembly and internal combustion engine comprising a valve rocker arm assembly

Abstract

The present application relates to a valve rocker arm assembly and an internal combustion engine comprising the valve rocker arm assembly. The valve rocker arm assembly comprises a switchable rocker arm and a lock mechanism, the switchable rocker arm comprises a first sub-arm and a second sub-arm mounted on a rocker shaft and capable of pivoting relative to each other about the rocker shaft, the lock mechanism comprises a locking sleeve slidably arranged between the rocker shaft and the switchable rocker arm and an actuator capable of moving the locking sleeve along the axial direction of the rocker shaft; the first sub-arm and the second sub-arm are respectively provided with a first accommodating cavity and a second accommodating cavity for accommodating the locking sleeve, the first accommodating cavity and the second accommodating cavity are respectively provided with a first locking groove and a second locking groove extending in the axial direction on the inner circumferential surface thereof, the outer circumferential surface of the locking sleeve is provided with locking teeth matched with the shapes of the first locking groove and the second locking groove, when the locking sleeve slides in the axial direction, the locking teeth cooperate with the first locking groove and / or the second locking groove, thereby locking or unlocking the first sub-arm and the second sub-arm from each other.

Description

Technical Field

[0001] This invention relates to the technical field of internal combustion engines, and more specifically, to valve rocker arm assemblies and internal combustion engines including valve rocker arm assemblies. Background Technology

[0002] To improve internal combustion engine performance, enhance fuel economy, and reduce emissions, variable valve timing mechanisms are commonly used. One known feasible solution is a switchable rocker arm, which comprises multiple arms, such as two arms pivotable relative to each other. The switchable rocker arm can be switched between locked and unlocked states by means of a locking mechanism to control valve actuation. In one possible embodiment, the locking mechanism has a locking pin; when the locking pin is in the engaged position, the switchable rocker arm is locked, causing the two arms to move in a single unit; when the locking pin is in the disengaged position, the switchable rocker arm is unlocked, allowing the two arms to move independently. In another possible embodiment, the switchable rocker arm, in different states, engages different cam lobe angles via different arms, such as low-lift, high-lift, and no-lift cam lobe angles, thereby transmitting different lifts to the valve stems of the associated intake or exhaust valves. The valve mechanism system switches rocker arm modes in a manner suitable for the operation of the internal combustion engine.

[0003] However, in the technical solution where the two arms of the switchable rocker arm are locked by a locking pin, since there is only one locking point between the two arms, if the shear stress of the locking pin is too high in some cases, this will result in the stiffness of the switchable rocker arm being too low, thereby limiting its service life and working mode. Summary of the Invention

[0004] The object of this invention is to provide a valve rocker arm assembly that achieves multi-point contact between the two arms of a switchable rocker arm to improve the overall rigidity of the assembly. Another object of this invention is to provide an internal combustion engine including such a valve rocker arm assembly.

[0005] To achieve the above objectives, the present invention provides a valve rocker arm assembly, including a switchable rocker arm and a locking mechanism. The switchable rocker arm includes a first and a second split arm mounted on a rocker arm shaft and pivotable relative to each other about the rocker arm shaft. The locking mechanism includes a locking sleeve and an actuator. The locking sleeve is slidably disposed between the rocker arm shaft and the first and second split arms of the switchable rocker arm and enables the first and second split arms to lock and unlock each other. The actuator actuates the locking sleeve, causing it to move between a locked position and a unlocked position of the first and second split arms. The first and second split arms each have a first receiving cavity and a second receiving cavity for accommodating the locking sleeve. The first and second receiving cavities are axially aligned along the rocker arm shaft and each has an axially extending first locking groove and a second locking groove on its inner circumferential surface. The outer circumferential surface of the locking sleeve is provided with locking teeth that match the shape of the first locking groove and the second locking groove. The locking sleeve can slide axially in the first receiving cavity and / or the second receiving cavity, so that the locking teeth cooperate with the first locking groove and / or the second locking groove, thereby locking or unlocking the first branch arm and the second branch arm.

[0006] In this invention, the valve rocker arm assembly includes a switchable rocker arm and a locking mechanism. The switchable rocker arm includes two branch arms that are pivotable relative to each other, one branch arm being connected to the camshaft and the other branch arm being connected to the valve connecting rod. The locking mechanism includes a locking sleeve and an actuator capable of actuating the locking sleeve. The locking mechanism can fix the two branch arms together by moving the locking sleeve of the locking mechanism, so that the two branch arms move as a single unit.

[0007] Therefore, depending on the position of the locking sleeve, the switchable rocker arm has two states: a locked state when the locking sleeve is in the connected position and an unlocked state when the locking sleeve is in the disengaged position. In the locked state, the locking sleeve is in the connected position, and the two arms cannot rotate relative to each other, for example, through a form-fitting mechanism. In the unlocked state, the locking sleeve is in a disengaged position, different from the connected position, and the two arms can move relative to each other, for example, by releasing the form-fitting connection. This invention does not limit the connection relationship between the two arms of the switchable rocker arm or the manner of relative movement. Because the switchable rocker arm, especially the two arms, has different motion characteristics in the two states, the switchable rocker arm, as a follower of the cam, responds differently to the cam driven by the camshaft, resulting in different valve lifts, thus realizing the "switchable" function of the rocker arm.

[0008] The locking sleeve is generally cylindrical, but can also be other shapes. The locking sleeve is slidably disposed between the rocker arm shaft and the two arms of the switchable rocker arm, and locking teeth are formed on the outer circumferential surface of the locking sleeve to engage with the shapes of the two arms, preventing relative movement between them. The locking sleeve is slidably fitted onto the rocker arm shaft and can be longitudinally disposed in either of the two arms; that is, the locking sleeve can be primarily accommodated by one of the two arms along its axial or long-side direction, with the locking teeth on the locking sleeve engaging with the other arm only when the locking sleeve is in the connected position. For this purpose, two receiving cavities are provided in each of the two arms to accommodate the locking sleeve, each cavity extending axially through the two arms, and each cavity has a locking groove extending axially on its inner circumferential surface that engages with the locking teeth on the locking sleeve. When the locking sleeve is in the disengaged position, it is primarily contained within one of the two receiving cavities, and its locking teeth do not engage with the locking groove of the other cavity. Therefore, both arms of the switchable rocker arm are in the unlocked state. However, when the locking sleeve is moved to the engaged position, its locking teeth engage with the locking grooves in both receiving cavities, thus locking both arms of the switchable rocker arm.

[0009] When the locking sleeve is in the connected position (i.e., when the two arms of the switchable rocker arm are locked), the locking teeth on the locking sleeve make surface-to-surface contact with the locking grooves in the two receiving cavities, thus achieving multi-point contact between the two arms of the switchable rocker arm, thereby improving the rigidity and service life of the entire assembly.

[0010] According to the present invention, an axially extending guide groove is formed on the inner peripheral surface of one of the first receiving cavity and the second receiving cavity, and an axially extending guide tooth is provided on the outer peripheral surface of the locking sleeve, which can be inserted into the guide groove. When the locking sleeve is in the connected position and the separated position, the guide tooth is accommodated in the guide groove.

[0011] Therefore, although the locking sleeve is mainly contained in one of the two receiving cavities when it is in the separated position, the guide teeth of the locking sleeve are always contained in the guide groove of the other of the two receiving cavities during the entire process of the locking sleeve sliding axially. This achieves circumferential positioning between the locking teeth on the locking sleeve and the locking groove in the receiving cavity.

[0012] In a preferred embodiment, the axial extension length of the guide tooth is greater than the axial extension length of the locking tooth. With this configuration, even if the locking tooth on the locking sleeve disengages from the locking groove of one of the two receiving cavities—in other words, even if the locking sleeve is in the separated position—it is still accommodated in the guide groove of that one of the two receiving cavities due to the longer length of the guide tooth. This provides more precise circumferential positioning when the locking tooth on the locking sleeve re-engages with the locking groove of that one of the two receiving cavities.

[0013] In a preferred embodiment, the circumferential dimension of the guide groove is greater than the circumferential dimension of the first locking groove or the second locking groove. For example, the circumferential dimension of the guide groove is equal to the sum of the circumferential dimensions of the three first locking grooves, or the circumferential dimension of the guide groove is equal to the sum of the circumferential dimensions of the three second locking grooves. Preferably, the circumferential dimension of the guide groove is greater than the maximum pivoting range of the first split arm driving the guide tooth about the rocker arm axis. When the locking sleeve is in the disengaged position, one split arm mounted on the camshaft will pivot relative to the other split arm about the rocker arm axis in response to the profile of the cam on the camshaft. Setting the circumferential dimension of the guide groove to be greater than the maximum pivoting range of the first split arm driving the guide tooth about the rocker arm axis at this time ensures that the other split arm connected to the valve linkage does not rotate when the two split arms are in the unlocked state.

[0014] According to the invention, the switchable rocker arm further includes a connector that connects the first split arm to the second split arm and enables the first split arm to pivot relative to the second split arm about the rocker arm axis. The connector may be a torsion spring. One end of the torsion spring is connected to one of the two split arms, and the other end is connected to the other of the two split arms. Thus, even when both split arms are in the unlocked state, the connector can prevent the two split arms from uncontrolled disengagement, thereby controlling to some extent the rotational impact between the two split arms and the locking sleeve, as well as the contact impact between the rocker arm and the camshaft.

[0015] According to the present invention, the valve rocker arm assembly further includes a stop formed on the side of the switchable rocker arm away from the actuator. The stop can be mounted in a groove formed on the rocker arm shaft and is positioned on the side of the switchable rocker arm away from the actuator. Thus, the stop and the actuator together clamp the switchable rocker arm therebetween, thereby achieving relative axial positioning of the two rocker arms. Furthermore, the stop prevents the locking sleeve from moving beyond its limit position, thereby limiting the amount of axial displacement of the locking sleeve.

[0016] In a preferred embodiment, the actuator is an electromagnet connected to one side of the locking sleeve via a power transmission member. The other side of the locking sleeve is provided with an elastic element capable of tensioning the locking sleeve in the direction of its movement. For example, if a stop is provided, an elastic element tensioning along the axial direction of the locking sleeve is provided between the stop and the locking sleeve. The elastic element is, for example, a coil spring. During the axial movement of the locking sleeve, when the two arms need to be locked together, the electromagnet overcomes the elastic restoring force of the elastic element, causing the locking teeth on the locking sleeve to engage with the locking grooves in the receiving cavity. When the two arms need to be unlocked, the electromagnet removes the external force, and the locking sleeve moves in the opposite direction under the elastic restoring force of the elastic element, causing the locking teeth on the locking sleeve to separate from the locking grooves in the receiving cavity, thereby ensuring the reliable operation of the locking mechanism.

[0017] In a preferred embodiment, the actuator is an electric motor connected to the locking sleeve via a power transmission mechanism, which is a rack and pinion structure. Advantageously, the operation of the electric motor is controlled by an electronic control unit, thereby enabling flexible adjustment of the valve lift of the corresponding valves according to the internal combustion engine configuration and the actual operating conditions of the transportation vehicle equipped with the internal combustion engine.

[0018] In a preferred embodiment, at least one corner of the locking tooth is chamfered or rounded. This makes it easier to match the locking tooth with the locking groove and reduces stress concentration on the locking tooth.

[0019] To achieve the above objectives, the present invention also proposes an internal combustion engine comprising the aforementioned valve rocker arm assembly. The locking mechanism in the internal combustion engine designed according to the present invention enables multi-point contact between the two split arms of the switchable rocker arm, thereby improving the rigidity of the entire valve rocker arm assembly and the service life of the entire internal combustion engine. Furthermore, the valve rocker arm assembly according to the present invention has a simple structure and is easy to install. Attached Figure Description

[0020] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings, wherein the same or similar reference numerals denote the same or similar features.

[0021] Figure 1 This is an exploded perspective view of the valve rocker arm assembly according to a first embodiment of the present invention.

[0022] Figure 2 This is a partial cross-sectional schematic diagram of a valve rocker arm assembly according to a first embodiment of the present invention.

[0023] Figure 3 This is a perspective view of a locking sleeve according to a first embodiment of the present invention.

[0024] Figure 4 This is a partial cross-sectional schematic diagram of the second receiving cavity according to the first embodiment of the present invention.

[0025] Figure 5 This is an exploded perspective view of the valve rocker arm assembly according to a second embodiment of the present invention.

[0026] Figure 6 This is a partial perspective view of a valve rocker arm assembly according to a second embodiment of the present invention.

[0027] Figure 7 This is a front view schematic diagram of a valve rocker arm assembly according to a second embodiment of the present invention.

[0028] Figure 8 This is a partial cross-sectional schematic diagram of a valve rocker arm assembly according to a second embodiment of the present invention.

[0029] Figure 9 This is a perspective view of a locking sleeve according to a second embodiment of the present invention.

[0030] Figure 10 This is an exploded perspective view of the valve rocker arm assembly according to a third embodiment of the present invention.

[0031] Figure 11 This is a front view schematic diagram of a valve rocker arm assembly according to a third embodiment of the present invention. Detailed Implementation

[0032] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of this application by way of example, but should not be used to limit the scope of this application, that is, this application is not limited to the described embodiments.

[0033] In the description of this application, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "inner," "outer," etc., indicating orientation or positional relationship are only for the convenience of describing this application 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, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0034] The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of this application. It should also be noted in the description of this application that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0035] The following is for reference. Figures 1 to 4 To describe the valve rocker arm assembly 100 according to a first embodiment of the present invention. Figures 1 to 4 As shown, the valve rocker arm assembly 100 includes a switchable rocker arm 110 and a locking mechanism 120. The locking mechanism 120 enables the switchable rocker arm 110 to switch between a locked state and an unlocked state.

[0036] The switchable rocker arm 110 has a split structure and includes a first split arm 111 connected to a camshaft (not shown) and a second split arm 112 connected to a valve link. The first split arm 111 and the second split arm 112 are mounted side-by-side on the rocker arm shaft 10 and are pivotable relative to each other about the rocker arm shaft 10. When the switchable rocker arm 110 is locked, the first split arm 111 and the second split arm 112 are fixedly connected to each other and cannot pivot relative to each other, thus the first split arm 111 and the second split arm 112 pivot about the rocker arm shaft 10 as a single unit. When the switchable rocker arm 110 is unlocked, the first split arm 111 and the second split arm 112 can pivot relative to each other; for example, the first split arm 111 connected to the camshaft will pivot about the rocker arm shaft 10 in response to the profile of the cam driven by the camshaft, while the second split arm 112 connected to the valve link will remain stationary.

[0037] The switchable rocker arm 110 also includes a connector 113 that connects the first split arm 111 to the second split arm 112 and enables the first split arm 111 to pivot relative to the second split arm 112 about the rocker arm axis 10. The connector 113 may be a torsion spring. One end of the torsion spring is connected to the first split arm 111, and the other end is connected to the second split arm 112. When the switchable rocker arm 110 is in the unlocked state, the first split arm 111, connected to the camshaft, will pivot relative to the second split arm 112, connected to the valve, about the rocker arm axis 10 in response to the profile of the cam on the camshaft and against the biasing force of the torsion spring 113. Therefore, on the one hand, it can ensure that the second split arm 112 will not pivot around the rocker arm shaft 10 when the switchable rocker arm 110 is in the unlocked state, thereby keeping the valve connected to the second split arm 112 unchanged and ensuring the normal operation of the entire assembly; on the other hand, the torsion spring 113 still connects the first split arm 111 and the second split arm 112 to each other when the switchable rocker arm 110 is in the unlocked state, thereby avoiding uncontrolled disengagement between the first split arm 111 and the second split arm 112, thereby controlling the rotational impact between the two split arms 111, 112 and the locking mechanism 120 and the contact impact between the first split arm 111 and the camshaft to a certain extent.

[0038] The locking mechanism 120 includes a locking sleeve 121, an actuator 122 capable of driving the locking sleeve 121, a power transmission member 123 that transmits the actuating force of the actuator 122 to the locking sleeve 121, and a stop member 124 disposed on the side of the locking sleeve 121 away from the actuator.

[0039] A locking sleeve 121 is slidably disposed between the rocker arm shaft 10 and the first branch arm 111 and the second branch arm 112 of the switchable rocker arm 110. The locking sleeve is generally cylindrical and slidably sleeved on the rocker arm shaft 10. The locking sleeve 121 has two positions: a connected position and a disengaged position. When the locking sleeve 121 is in the connected position, the first branch arm 111 and the second branch arm 112 are locked together, thus switching the rocker arm 110 to a locked state. When the locking sleeve 121 is in the disengaged position, the first branch arm 111 and the second branch arm 112 are unlocked and can pivot relative to each other, thus switching the rocker arm 110 to an unlocked state. The locking and unlocking of the first branch arm 111 and the second branch arm 112 of the switchable rocker arm 110 by the locking sleeve 121 will be described in detail below.

[0040] like Figures 1 to 4As shown, the first arm 111 and the second arm 112 each have a first receiving cavity 111a and a second receiving cavity 112a for accommodating the locking sleeve 121. The first receiving cavity 111a and the second receiving cavity 112a are aligned axially along the rocker arm shaft 10 and respectively extend axially through the first arm 111 and the second arm 112. When the locking sleeve 121 is in the separated position, the locking sleeve 121 is mainly accommodated by one of the first receiving cavity 111a and the second receiving cavity 112a. In the first embodiment, when the locking sleeve 121 is in the separated position, the locking sleeve 121 is mainly accommodated by the first receiving cavity 111a of the first arm 111.

[0041] The first receiving cavity 111a and the second receiving cavity 112a are respectively provided with a first locking groove 111b and a second locking groove 112b extending axially on their inner peripheral surfaces. The first locking groove 111b and the second locking groove 112b are respectively recessed radially outward from their respective inner peripheral surfaces. Correspondingly, the outer peripheral surface of the locking sleeve 121 is provided with locking teeth 121a that match the shape of the first locking groove 111b and the second locking groove 112b. The locking teeth 121a extend axially along the locking sleeve 121 and protrude radially outward from the outer peripheral surface of the locking sleeve 121. The axial extension length of the locking teeth 121a is less than the axial length of the locking sleeve 121. Figure 3 As shown, the locking tooth 121a can be located at approximately the center of the locking sleeve 121. At least one corner of the locking tooth 121a can be chamfered or rounded. In this way, on the one hand, the locking tooth 121a can be more easily inserted into the first locking groove 111b and the second locking groove 112b, and on the other hand, stress concentration on the locking tooth 121a can be reduced.

[0042] When the locking sleeve 121 is in the connected position, the locking tooth 121a engages with both the first locking groove 111b and the second locking groove 112b, meaning the locking tooth 121a is simultaneously inserted into both the first locking groove 111b and the second locking groove 112b, thereby locking the first split arm 111 and the second split arm 112 together. When the locking sleeve 121 is in the disengaged position, the locking tooth 121a engages with only one of the first locking groove 111b and the second locking groove 112b, thereby unlocking the first split arm 111 and the second split arm 112 together. In the first embodiment, when the locking sleeve 121 is in the disengaged position, the locking tooth 121a is only inserted into the first locking groove 112a and not into the second locking groove 112b. At this time, the locking sleeve 121 is mainly accommodated by the first receiving cavity 112a of the first split arm 112.

[0043] The actuator 122 can transmit its actuating force to the locking sleeve 121 via the power transmission member 123, causing the locking sleeve 121 to move between a connected position and a disengaged position. According to a first embodiment of the invention, the actuator is an electromagnet 122, and the power transmission member 123 is a push rod. The push rod 123 is generally L-shaped and is disposed between the locking sleeve 121 and the electromagnet 122.

[0044] The stop 124 can be installed in a groove formed on the rocker arm shaft 10. Thus, the stop 124 and the actuator 122 together clamp the switchable rocker arm 110 therebetween, thereby achieving relative axial positioning of the first split arm 111 and the second split arm 112. Furthermore, the stop 124 prevents the locking sleeve 124 from moving beyond its limit position, thereby limiting the amount of axial displacement of the locking sleeve 124.

[0045] The locking mechanism 120 also includes an elastic element 125 disposed on the side of the locking sleeve 121 away from the electromagnet to tension and bias the locking sleeve 121 toward its direction of movement. The elastic element 125 is, for example, a coil spring. The elastic element 125 is sandwiched between the locking sleeve 121 and the stop member 124. Thus, one end of the locking sleeve 121 is connected to the electromagnet 122 via the push rod 123, while the other end of the locking sleeve 121 is connected to the elastic element 125.

[0046] Therefore, when the electromagnet 122 is energized, it overcomes the elastic force of the elastic element 125 to push the push rod 123, causing the locking sleeve 121 to move axially to the left, disengaging the locking tooth 121a from the first locking groove 111b, thereby unlocking the first arm 111 and the second arm 112. When the electromagnet 122 is de-energized, the locking sleeve 121 moves to the right under the elastic restoring force of the elastic element 125, engaging the locking tooth 121a with both the first locking groove 111b and the second locking groove 112b, thereby locking the first arm 111 and the second arm 112 together, allowing them to pivot as a single unit around the rocker arm axis 10.

[0047] Therefore, when the locking sleeve 121 is in the connected position, that is, when the first branch arm 111 and the second branch arm 112 of the switchable rocker arm 110 are in the locked state, the locking teeth 121a on the locking sleeve 121 engage with the first locking groove 111b of the first branch arm 111 and the second locking groove 112b of the second branch arm 112. This achieves surface-to-surface contact between the locking teeth 121a and the two locking grooves 111b and 112b, thus achieving multi-point contact between the two branches 111 and 112 of the switchable rocker arm 110, thereby improving the rigidity and service life of the entire assembly.

[0048] In a preferred embodiment, there can be multiple first locking grooves 111b, which can be evenly distributed on the inner circumferential surface of the first receiving cavity 111a. Similarly, there can be multiple second locking grooves 112b, which can be evenly distributed on the inner circumferential surface of the second receiving cavity 112a. Correspondingly, there can also be multiple locking teeth 121a, which are evenly distributed on the outer circumferential surface of the locking sleeve 121. The multiple locking teeth 121a respectively engage with the multiple first locking grooves 111b and the multiple second locking grooves 112b, thereby further improving the rigidity and service life of the entire assembly.

[0049] A guide groove 114 extending axially is formed on the inner peripheral surface of one of the first receiving cavity 111a and the second receiving cavity 112a, and a guide tooth 121b extending axially and capable of being inserted into the guide groove 114 is provided on the outer peripheral surface of the locking sleeve 121. When the locking sleeve 121 is in the connected position and the disengaged position, the guide tooth 121b is accommodated in the guide groove 114. According to the first embodiment of the present invention, the guide groove 114 is formed on the inner peripheral surface of the second receiving cavity 112a.

[0050] The axial extension length of the guide tooth 121b is greater than the axial extension length of the locking tooth 121a. Therefore, even when the locking sleeve 121 is in the disengaged position, i.e., when the locking tooth 121a only engages with one of the first locking groove 111b and the second locking groove 112b, the guide tooth 121b is still accommodated in the guide groove 114. This provides more accurate circumferential positioning when the locking tooth 121a re-engages with both the first locking groove 111b and the second locking groove 112b. Preferably, for ease of installation, the axial extension length of the guide tooth 121b is less than the axial length of the locking sleeve 121.

[0051] Preferably, the circumferential dimension of the guide groove 114 is larger than the circumferential dimension of the first locking groove 111b or the second locking groove 112b. For example, as Figure 4As shown, the circumferential dimension of the guide groove 114 is equal to the sum of the circumferential dimensions of the three first locking grooves 111b, or the circumferential dimension of the guide groove 114 is equal to the sum of the circumferential dimensions of the three second locking grooves 112b. More preferably, the circumferential dimension of the guide groove 114 is greater than the maximum pivot range of the guide tooth 121b driven by the first split arm 111 around the rocker arm axis 10. Therefore, when the locking sleeve 121 is in the disengaged position, the first split arm 111 connected to the camshaft will pivot around the rocker arm shaft 10 in response to the profile of the cam driven by the camshaft. At this time, the guide tooth 121b housed in the first split arm 111 will rotate in the guide groove 114 as the first split arm 111 pivots. However, since the circumferential dimension of the guide groove 114 is greater than the maximum pivot range of the guide tooth 121b driven by the first split arm 111 around the rocker arm shaft 10, the guide tooth 121b will not drive the second split arm 112 to rotate, so the second split arm 112 will remain stationary, thereby maintaining the valve state when the locking sleeve 121 is in the disengaged position.

[0052] The following is for reference. Figures 5 to 9 The valve rocker arm assembly 200 according to a second embodiment of the present invention will be described. The valve rocker arm assembly 200 according to the second embodiment of the present invention is generally the same as the valve rocker arm assembly 100 according to the first embodiment of the present invention. Specifically, the first branch arm 211, the second branch arm 212, and the connector 213 in the switchable rocker arm 210 of the second embodiment are the same as the first branch arm 111, the second branch arm 112, and the connector 113 in the switchable rocker arm 110 of the first embodiment. The first branch arm 211 and the second branch arm 212 respectively have a first receiving cavity and a second receiving cavity for receiving a locking sleeve 221. The first receiving cavity and the second receiving cavity respectively have a first locking groove and a second locking groove extending axially on their inner circumferential surfaces. The valve rocker arm assembly 200 according to the second embodiment of the present invention differs from the valve rocker arm assembly 100 according to the first embodiment of the present invention only in terms of the locking mechanism 220, which will be described in detail below.

[0053] According to a second embodiment of the present invention, the locking sleeve 221 is mainly accommodated by the second receiving cavity of the second branch arm 212, and the guide groove is formed on the inner circumferential surface of the first receiving cavity of the first branch arm 211.

[0054] According to the second embodiment of the present invention, the actuator 222 is a single motor, and the power transmission component 223 is a gear and rack structure. The gear and rack structure includes a rack 2231 connected to the locking sleeve 221 and a gear 2232 connected to the motor 222. The motor 222 drives the locking sleeve 221 to move axially between the connected position and the disconnected position via the meshing between the gear 2232 and the rack 2231.

[0055] When the motor 222 rotates in the forward direction, the rack 2231 pushes the locking sleeve 221 to move axially, for example, to the left, engaging the locking tooth 221a with both the first locking groove and the second locking groove, thereby locking the first arm 211 and the second arm 212 together so that they can pivot as a single unit about the rocker arm shaft 10. When the motor 222 rotates in the reverse direction, the rack 2231 pulls the locking sleeve 221 to move axially, for example, to the right, disengaging the locking tooth 221a from the first locking groove on the first arm 211, thereby unlocking the first arm 211 and the second arm 212. At this time, the guide tooth 221b of the locking sleeve 221 is still accommodated in the guide groove of the first receiving cavity, so that the locking tooth 221a can simultaneously engage with the first locking groove of the first arm 211 and the second locking groove of the second arm 212 to provide more precise circumferential positioning.

[0056] Compared with the valve rocker arm assembly 100 according to the first embodiment of the present invention, the valve rocker arm assembly 200 according to the second embodiment of the present invention does not require the provision of an elastic element, and the valve lift of the corresponding valve can be flexibly adjusted according to the internal combustion engine configuration and the actual working conditions of the transportation vehicle equipped with the internal combustion engine by controlling the single unit 222.

[0057] The following is for reference. Figures 10 to 11 The valve rocker arm assembly 300 according to a third embodiment of the present invention will be described below. The valve rocker arm assembly 300 according to the third embodiment of the present invention includes two switchable rocker arms 310A and 310B, and two motors 322A and 322B respectively controlling the locking / unlocking of the switchable rocker arms 310A and 310B. The control of the switchable rocker arm 310A by motor 322A through locking sleeve 321A and the control of the switchable rocker arm 310B by motor 322B through locking sleeve 321B are the same as the control of the switchable rocker arm 210 by motor 222 in the second embodiment, and will not be repeated here.

[0058] Since the valve rocker arm assembly according to the third embodiment of the present invention uses two motors, independent control of the two valve rocker arm assemblies can be achieved, thereby increasing the control window of the valve rocker arm assembly and improving the more efficient operation of the internal combustion engine.

[0059] Furthermore, according to the present invention, an internal combustion engine is also provided, which can be equipped with any of the above-described valve rocker arm assemblies 100, 200, and 300. Since the locking mechanism in the valve rocker arm assemblies 100, 200, and 300 can achieve multi-point contact between the two split arms of the switchable rocker arm, the system rigidity and service life of the entire internal combustion engine can be improved, and the structure of the entire internal combustion engine can be simplified.

[0060] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A valve rocker arm assembly, comprising a switchable rocker arm and a locking mechanism, said switchable rocker arm including a first and a second split arm mounted on a rocker arm shaft and pivotable relative to each other about said rocker arm shaft, characterized in that, The locking mechanism includes a locking sleeve and an actuator. The locking sleeve is slidably disposed between the rocker arm shaft and the first and second branch arms of the switchable rocker arm and is capable of locking and unlocking the first and second branch arms. The actuator is capable of actuating the locking sleeve, causing the locking sleeve to move between a connected position where the first and second branch arms are locked together and a separated position where the first and second branch arms are unlocked. The first arm and the second arm each have a first receiving cavity and a second receiving cavity for accommodating the locking sleeve. The first receiving cavity and the second receiving cavity are aligned along the axial direction of the rocker arm shaft and each has a first locking groove and a second locking groove extending along the axial direction on its inner circumferential surface. The outer circumferential surface of the locking sleeve is provided with locking teeth that match the shape of the first locking groove and the second locking groove. The locking sleeve can slide along the axial direction in the first receiving cavity and / or the second receiving cavity, so that the locking teeth cooperate with the first locking groove and / or the second locking groove to lock or unlock the first branch arm and the second branch arm to each other.

2. The valve rocker arm assembly according to claim 1, characterized in that, The inner circumferential surface of one of the first receiving cavity and the second receiving cavity is further provided with a guide groove extending along the axial direction, and the outer circumferential surface of the locking sleeve is further provided with a guide tooth extending along the axial direction and capable of being inserted into the guide groove, wherein the guide tooth is accommodated in the guide groove when the locking sleeve is in the connected position and the separated position.

3. The valve rocker arm assembly according to claim 2, characterized in that, The guide tooth extends along the axial direction for a longer length than the locking tooth extends along the axial direction, and the circumferential dimension of the guide groove is greater than the circumferential dimension of the first locking groove or the second locking groove.

4. The valve rocker arm assembly according to claim 2, characterized in that, The circumferential dimension of the guide groove is greater than the maximum pivot range of the guide teeth around the rocker arm shaft driven by the first split arm.

5. The valve rocker arm assembly according to claim 1, characterized in that, The switchable rocker arm further includes a connector that connects the first split arm to the second split arm and enables the first split arm to pivot relative to the second split arm about the rocker arm axis.

6. The valve rocker arm assembly according to claim 1, characterized in that, At least one corner of the locking tooth is chamfered or rounded.

7. The valve rocker arm assembly according to claim 1, characterized in that, The valve rocker arm assembly also includes a stop formed on the side of the switchable rocker arm away from the actuator.

8. The valve rocker arm assembly according to any one of claims 1 to 7, characterized in that, The actuator is an electromagnet, which is connected to one side of the locking sleeve via a power transmission component. The other side of the locking sleeve is provided with an elastic element that can tension the locking sleeve in the direction of movement of the locking sleeve.

9. The valve rocker arm assembly according to any one of claims 1 to 7, characterized in that, The actuator is an electric motor, which is connected to the locking sleeve via a power transmission component, which is a gear and rack structure.

10. An internal combustion engine, characterized in that, The internal combustion engine includes a valve rocker arm assembly according to any one of claims 1 to 9.

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