Valve timing mechanism of engine

Abstract

The utility model discloses an engine valve mechanism which comprises a valve bridge and a valve, a mounting groove is formed in the end portion of the valve bridge, the mounting groove is recessed inwards from the bottom face of the valve bridge, the right side of the mounting groove is open, and the valve comprises a valve rod and a valve head. A plurality of first convex parts are arranged on the front and rear outer side surfaces of the valve bridge end part; the buckle is of a hollow structure, the left side and the upper side of the buckle are open, a plurality of first through holes in interference fit with the first convex parts are formed in the front side and the rear side of the buckle, and a first hollow part and a second hollow part matched with the mounting groove are arranged at the bottom and the right side of the buckle respectively; the first hollowed-out part, the second hollowed-out part and the mounting groove form a first space for containing the upper end of the valve rod, first arcs are symmetrically arranged in the middles of the front side and the rear side of the first hollowed-out part, first grooves are formed in the positions, corresponding to the first arcs, of the upper end of the valve rod, and the diameter of the first grooves is smaller than that of the first arcs. The height of the first groove is larger than the thickness of the bottom of the buckle.

Description

Technical Field

[0001] This utility model relates to the field of engine technology, and in particular to an engine valve train mechanism. Background Technology

[0002] In the engine's valve train, the valve bridge is a crucial component connecting two valves of the same name on the same cylinder head. Its core function is to ensure that the two valves maintain synchronized movement during opening and closing, thereby achieving efficient intake and exhaust processes. As the engine's "breathing system," the valve train consists of components such as valves, valve seats, valve springs, camshaft, tappets, pushrods, rocker arms, and the valve bridge. Its operational precision directly affects the engine's power, fuel economy, and emissions performance. For engines employing a dual-valve (or multi-valve) design, the valve bridge contacts the valve stem tips through mounting slots at both ends, evenly distributing the motion load transmitted by the camshaft to the two valves. This avoids problems such as uneven valve wear, poor sealing, or misalignment caused by uneven force on individual valves. During engine operation, the camshaft drives the valve bridge in reciprocating motion via the cam profile. The valve bridge bears the periodic load of the cam contact area and transmits motion commands through rigid contact with the valve stem. Its stability and reliability directly determine the accuracy of the valve timing and the fit precision of the valve sealing surfaces. Especially under high-speed operating conditions, the valve bridge needs to complete high-frequency reciprocating motion in a very short time. The smoothness of its motion trajectory not only affects the cylinder scavenging efficiency, but is also closely related to the vibration and noise characteristics of the engine.

[0003] However, existing valve bridge designs face significant technical bottlenecks when dealing with high-speed engine operation. As the engine enters the high-speed range, the frequency and acceleration of the valve bridge's reciprocating motion increase dramatically, and the inertial force generated by its own mass becomes a key factor affecting motion stability. Traditional valve bridges typically employ a rigid connection structure, relying solely on the contact between the valve stem tip and the mounting groove to maintain motion constraint. During high-speed reciprocating motion, the valve bridge may momentarily detach from the valve stem due to inertial forces, resulting in a "flyaway" phenomenon. This abnormal movement not only disrupts the accuracy of valve timing, leading to insufficient intake or incomplete exhaust, but may also cause a risk of valve-piston collision, seriously threatening engine safety. To address this issue, existing technologies primarily employ two approaches: first, optimizing the cam profile design to reduce the peak acceleration of the valve bridge by slowing the rate of change of cam lift. However, this method sacrifices valve opening duration and lift, leading to decreased charging efficiency at mid-to-high speeds. Second, increasing the structural weight of the valve bridge to suppress vibration tendencies of moving parts by increasing inertial mass. However, the additional mass exacerbates the load on the cam contact area, increasing contact stress between the camshaft and valve bridge, increasing friction loss and wear risk. It also places higher demands on the load capacity of the valve springs, disrupting the original dynamic balance of the valve train. Both solutions require significant modifications to the core components of the valve train, increasing design complexity and manufacturing costs, and potentially introducing new reliability issues, making it difficult to achieve an ideal balance between motion stability and power performance. Therefore, how to improve the motion constraint capability of the valve bridge under high-speed conditions through structural innovation within the existing valve train architecture has become a pressing technical challenge.

[0004] The above background information is provided only to aid in understanding the concept and technical solution of this utility model. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above information was disclosed on the filing date of this patent application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Utility Model Content

[0005] The purpose of this invention is to propose an engine valve train mechanism to solve the technical problem in the prior art where the valve bridge may momentarily detach from the valve stem due to inertial force, resulting in a "flying off" phenomenon.

[0006] Therefore, this utility model proposes an engine valve train mechanism.

[0007] Preferably, the present invention may also have the following technical features:

[0008] An engine valve train includes a valve bridge and valves. The valve bridge has a mounting groove at its end, which is recessed inward from the bottom surface of the valve bridge and has an opening on the right side. The valve includes a valve stem and a valve head.

[0009] The valve bridge end has several first protrusions on its front and rear outer sides.

[0010] It also includes a buckle fitted onto the end of the valve bridge, which is a hollow structure with openings on the left and top sides. Several first through holes that are interference fit with the first protrusion are provided on the front and rear sides. A first hollow part and a second hollow part that match the mounting groove are respectively provided on the bottom and right side. The first hollow part, the second hollow part and the mounting groove form a first space to accommodate the upper end of the valve stem. A first arc is symmetrically provided in the middle of the front and rear sides of the first hollow part. A first groove is provided on the upper end of the valve stem corresponding to the position of the first arc. The diameter of the first groove is smaller than the diameter of the first arc. The height of the first groove is greater than the thickness of the bottom of the buckle.

[0011] Preferably, two first protrusions are provided at intervals on the front and rear outer sides of the valve bridge end, and the first protrusions on both sides are symmetrically arranged.

[0012] Preferably, the two first protrusions on the same side are arranged side by side laterally.

[0013] Preferably, the two first protrusions on the same side are longitudinally stacked.

[0014] Preferably, the first through hole is an oblong hole, and the corresponding first protrusion is an oblong protrusion.

[0015] Preferably, the width of the second hollow portion is the same as the width of the mounting groove.

[0016] Preferably, a gradually widening inclined surface is formed from the right end of the first arc to the edge of the second hollow portion.

[0017] The beneficial effects of this utility model compared with the prior art include:

[0018] 1. The valve train mechanism of this application, with its first groove on the valve stem and the first arc on the latch, defines a clear boundary for the left and right movement of the valve stem, forming a reliable lateral limiting mechanism; the fit between the first groove and the bottom of the latch sets a range for the up and down movement of the valve stem. This multi-dimensional limiting design effectively restricts the valve stem to move within the latch to a limited extent, fundamentally preventing the valve bridge from "flying off," greatly improving the stability of the valve train mechanism at high speeds, and ensuring the accuracy and reliability of the engine's valve timing; the interference fit between the latch and the valve bridge end through multiple first protrusions and first through holes increases the contact area and connection tightness between the two, enhancing the overall structural strength.

[0019] 2. The four first protrusions symmetrically distributed on the front and rear sides of this application are interference-fitted with the first through holes at corresponding positions on the buckle, forming a multi-point fastening connection. This effectively disperses the force between the buckle and the valve bridge, avoiding loosening or damage caused by excessive force at a single point, greatly improving the firmness of the connection between the buckle and the valve bridge, and ensuring stability under high-frequency vibration conditions of the engine. Attached Figure Description

[0020] Figure 1 This is a first schematic diagram of a specific embodiment of the present utility model.

[0021] Figure 2 This is a second schematic diagram of a specific embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram of a valve bridge according to a specific embodiment of the present invention.

[0023] Figure 4 This is a first schematic diagram of the buckle in a specific embodiment of this utility model.

[0024] Figure 5 This is a second schematic diagram of the buckle in a specific embodiment of this utility model.

[0025] Figure 6 This is a cross-sectional view of a specific embodiment of the present utility model.

[0026] Figure 7 This is a utility model Figure 6 Enlarged diagram of point A in the middle.

[0027] Explanation of reference numerals in the attached drawings: 01-Valve bridge; 11-Mounting groove; 12-First protrusion; 02-Valve; 21-Valve stem; 211-First groove; 22-Valve head; 03-Snap-on; 31-First through hole; 32-First hollow part; 33-Second hollow part; 34-First arc; 04-First space. Detailed Implementation

[0028] The present invention will now be described in further detail with reference to specific embodiments and the accompanying drawings. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope and application of the present invention.

[0029] Non-limiting and non-exclusive embodiments will be described with reference to the following figures, wherein the same reference numerals denote the same parts unless otherwise specifically stated.

[0030] An engine valve train, such as Figures 1-7 As shown, the device includes a valve bridge 01 and a valve 02. The valve bridge 01 has a mounting groove 11 at its end, which is recessed inwards from the bottom surface of the valve bridge 01 and opens on its right side. The valve 02 includes a valve stem 21 and a valve head 22. The valve bridge 01 has several first protrusions 12 on its front and rear outer sides. It also includes a buckle 03 fitted onto the end of the valve bridge 01. This buckle is hollow, with openings on the left and top sides, and several first through holes 31 on its front and rear sides that are interference-fitted with the first protrusions 12. The bottom and right sides also have... A first hollow portion 32 and a second hollow portion 33 are respectively provided to match the mounting groove 11. The first hollow portion 32 and the second hollow portion 33 form a first space 04 with the mounting groove 11 to accommodate the upper end of the valve stem 21. A first arc 34 is symmetrically provided in the middle of the front and rear sides of the first hollow portion 32. A first groove 211 is provided at the upper end of the valve stem 21 corresponding to the position of the first arc 34. The diameter of the first groove 211 is smaller than the diameter of the first arc 34, and the height of the first groove 211 is greater than the thickness of the bottom of the buckle 03.

[0031] Specifically, such as Figures 5-7 As shown, this is a schematic diagram of a section cut along the central axis of the valve stem 21. The distance between the two first arcs 34 (that is, the distance between the widest points of the two first arcs 34) is L3, the width of the first groove 211 is L1, and the width of the mounting groove 11 of the valve bridge 01 (almost equal to the diameter of the upper end of the valve stem 21) is L2, such that L1 < L3 < L2. The first groove 211 cooperates with the two first arcs 34, so that the valve stem 21 can move left and right within the range of the two first arcs 34 when it is working.

[0032] The design of the first groove 211 on the valve stem 21 and the first arc 34 on the latch 03 defines a clear boundary for the left and right movement of the valve stem 21, forming a reliable lateral limiting mechanism. The fit between the first groove 211 and the bottom of the latch 03 sets a range for the up and down movement of the valve stem 21. This multi-dimensional limiting design effectively restricts the valve stem 21 to a limited extent within the latch 03, fundamentally preventing the valve bridge 01 from "flying off," greatly improving the stability of the valve train at high speeds, and ensuring the accuracy and reliability of the engine's valve timing. The interference fit between the latch 03 and the valve bridge 01 end through multiple first protrusions 12 and first through holes 31 increases the contact area and connection tightness between the two, enhancing the overall structural strength.

[0033] In some examples of this embodiment, such as Figures 1-3 As shown, two first protrusions 12 are respectively spaced apart on the front and rear outer sides of the valve bridge 01. The first protrusions 12 on both sides are symmetrically arranged. The four first protrusions 12 symmetrically distributed on the front and rear sides are interference-fitted with the first through holes 31 at corresponding positions on the buckle 03, forming a multi-point fastening connection. This effectively disperses the force between the buckle 03 and the valve bridge 01, avoiding loosening or damage caused by excessive force at a single point, greatly improving the firmness of the connection between the buckle 03 and the valve bridge 01, and ensuring stability under high-frequency vibration conditions of the engine. The four first protrusions 12 form a clear positioning reference, providing guidance when pressing the buckle 03, reducing assembly difficulty. The spacing design is more tolerant of small dimensional tolerances of the valve bridge 01 or the buckle 03. Even if a single first protrusion 12 has a slight deviation, the remaining first protrusions 12 can still provide effective support, ensuring assembly reliability. In some examples, such as Figures 1-3 As shown, the two first protrusions 12 on the same side are arranged side by side in a transverse direction, which can significantly enhance the circumferential connection strength between the buckle 03 and the valve bridge 01 within the limited transverse space at the end of the valve bridge 01. The two points of transverse force can effectively resist the torsional force generated by the buckle 03 during engine operation, prevent the buckle from shifting or rotating in a circumferential direction, and ensure that it always maintains a precise fit with the valve bridge 01.

[0034] In other examples, the two first protrusions 12 on the same side are longitudinally stacked. When the two first protrusions 12 on the same side are longitudinally stacked, a double limiting structure can be formed in the axial direction, which greatly improves the axial connection stability between the latch 03 and the valve bridge 01. Under high engine speed conditions, this stacked layout can effectively limit the movement of the latch 03 along the axial direction of the valve stem 01, preventing the latch 03 from loosening or falling off due to inertial force, and further enhancing the suppression effect on the "flying off" phenomenon of the valve bridge 01. In some other examples, provided there is enough space, other numbers of first protrusions 12 can also be provided. The specific number and setting position are not limited, as long as the first protrusion 12 can be interference-fitted with the first through hole 31, so that the latch 03 is fixedly set on the valve bridge 01.

[0035] In other examples of this embodiment, such as Figure 1 , 3 As shown in Figure 4, the first through hole 31 is an oblong hole, and the corresponding first protrusion 12 is an oblong protrusion. The oblong structure provides a larger contact area along its long axis, which, compared to the traditional circular fit, allows the latch 03 and the valve bridge 01 to obtain more reliable constraints in both the lateral and longitudinal dimensions. When the engine generates complex vibrations during operation, this multi-directional constraint mechanism can effectively suppress the displacement tendency of the latch, ensuring that it always maintains a tight fit with the valve bridge 01, and significantly reducing the risk of loosening caused by vibration.

[0036] In other examples of this embodiment, such as Figures 1-5 As shown, the width of the second hollow portion 33 is the same as the width of the mounting groove 11. The second hollow portion 33 of the buckle 03 and the mounting groove 11 of the valve bridge 01 form a precise fit in structure, ensuring that a smooth transition lateral opening channel is formed after the two are connected. The width of this channel is adapted to the outer diameter of the valve stem 01, ensuring that the valve stem 01 can slide into the first space. Specifically, as shown... Figures 1-5 As shown, a gradually widening inclined surface is formed from the right end of the first arc 34 to the edge of the second hollow portion 33. During assembly, the valve stem 21 can smoothly slide into the first space 04 formed by the first hollow portion 32, the second hollow portion 33, and the mounting groove 11 along this inclined surface. The guiding effect of the inclined surface effectively reduces the assembly difficulty and avoids jamming between the valve stem 01 and the edge of the clip 03 due to slight positional deviations, significantly improving assembly efficiency and success rate.

[0037] Those skilled in the art will recognize that numerous variations are possible with respect to the above description, and the embodiments and figures are merely for describing one or more specific implementations.

[0038] Although exemplary embodiments of the present invention have been described and illustrated, those skilled in the art will understand that various changes and substitutions can be made thereto without departing from the spirit of the present invention. Furthermore, many modifications can be made to adapt specific situations to the doctrine of the present invention without departing from the central concept of the present invention described herein. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but may include all embodiments and equivalents that fall within the scope of the present invention.

Claims

1. An engine valve train, comprising a valve bridge and a valve, the valve bridge is provided with a mounting slot at the end thereof, the mounting slot is recessed inwardly from the bottom surface of the valve bridge, the mounting slot is open at the right side, the valve comprises a valve stem and a valve head; characterized in that: a plurality of first protrusions are arranged on the front and rear outer sides of the end of the valve bridge; a buckle is further arranged on the end of the valve bridge, the buckle is a hollow structure, open at the left side and the upper side, provided with a plurality of first through holes on the front and rear sides in interference fit with the first protrusions, provided with a first hollow part and a second hollow part on the bottom and the right side respectively in match with the mounting slot, the first hollow part, the second hollow part and the mounting slot form a first space for accommodating the upper end of the valve stem, the first hollow part is symmetrically provided with a first circular arc in the middle of the front and rear sides, the upper end of the valve stem is provided with a first groove at the position corresponding to the first circular arc, the diameter of the first groove is smaller than the diameter of the first circular arc, and the height of the first groove is greater than the thickness of the bottom of the buckle.

2. An engine valve train according to claim 1, characterised in that: The first protrusions are arranged in pairs on the front and rear outer sides of the end of the valve bridge respectively, and the first protrusions on the two sides are symmetrically arranged.

3. An engine valve train according to claim 2, characterised in that: The two first protrusions on the same side are arranged transversely side by side.

4. The engine valve train of claim 2 wherein: The two first protrusions on the same side are arranged longitudinally in layers.

5. The engine valve train of claim 1 wherein: The first through hole is a waist-shaped hole, and the corresponding first protrusion is a waist-shaped protrusion.

6. The engine valve train of claim 1 wherein: The width of the second hollow part is consistent with the width of the mounting slot.

7. An engine valve train according to claim 6, characterised in that: From the right end of the first circular arc to the edge of the second hollow part, an inclined surface gradually widening is formed.

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