Engine floating tensioning timing system
The design of the floating tensioning timing system solves the problems of low universality and severe wear of the existing timing chain system, achieves cost reduction and performance improvement, and ensures the stable operation of the engine.
Patent Information
- Application Number
- CN202510700934.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-28
- Publication Date
- 2025-09-19
AI Technical Summary
The existing timing chain system has problems such as low component commonality, high manufacturing cost, severe wear, high NVH level and timing error caused by chain elongation, which affects engine performance and reliability.
A floating tension timing system is adopted, including a support plate, bearing seat, camshaft sprocket, fixed block, spring and chain. The vertical movement of the camshaft sprocket is achieved through the design of sliding bearings and guide grooves. Combined with oil pressure and spring buffering, the chain swing amplitude and dynamic tension are reduced.
It improves the commonality of parts, reduces manufacturing costs, extends the service life of the chain system, reduces noise and vibration, compensates for timing errors caused by chain elongation, and improves the overall performance and reliability of the engine.
Smart Images
Figure CN120667225A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of engine timing, and in particular to an engine floating tensioning timing system. Background Art
[0002] The timing chain system is a critical component of the engine. Its primary function is to transmit crankshaft power to the camshaft via the chain, thereby driving the valves to open and close on time, ensuring continuous and efficient engine operation. The performance of the timing system directly affects the engine's valve timing. A malfunction can cause valve-piston collisions, resulting in engine malfunction or even serious damage. Therefore, the reliability, stability, and service life of the timing chain system are crucial to overall engine performance.
[0003] Existing timing chain systems typically consist of a crankshaft sprocket, a moving guide rail, a fixed guide rail, a chain, a tensioner, and a camshaft sprocket. During engine operation, the speed of the crankshaft sprocket and the torque of the camshaft sprocket fluctuate significantly as the crankshaft angle changes. This fluctuation causes the chain to swing widely during movement, especially on the slack side of the chain, causing severe friction and collisions. These problems not only increase the system's noise level but also significantly reduce the service life of the chain system and increase maintenance costs. In addition, since the chain may stretch and elongate during long-term operation, this may lead to timing errors, which in turn affects the engine's combustion efficiency and may even cause valve-piston collisions, resulting in engine failure.
[0004] While existing timing chain systems can meet the operating requirements of engines to a certain extent, they have some significant shortcomings. For example, the commonality rate of components is low. Due to layout constraints, the movable and fixed guide rails often need to be redesigned and re-molded for each project, which is costly. In addition, due to the lack of an effective tensioning device, the tight-side chain is prone to swing during operation, exacerbating system wear and significantly reducing the service life of the chain system. At the same time, because the loose-side chain of the timing system has a large number of links, a tensioner is required to press the movable rail to prevent the loose-side chain from jumping teeth. This increases the dynamic tension of the system, increases the NVH level, and reduces the service life of the chain system. Moreover, the long-term tension on the chain causes the chain to elongate, which can lead to certain timing errors, affecting engine combustion efficiency. In severe cases, the valve may press against the piston, resulting in engine failure.
[0005] Therefore, developing a new timing chain system that can solve the above problems has important practical significance and broad application prospects. Summary of the Invention
[0006] The technical problem to be solved by the present invention is to provide an engine floating tensioning timing system, which reduces manufacturing costs and simplifies the system layout by improving the commonality of components, while effectively reducing the swing amplitude of the tight-side chain, thereby significantly improving the service life of the chain system; in addition, the dynamic tension of the timing system is reduced by optimizing the design, thereby reducing the NVH (noise, vibration and harshness) level of the system, and solving the timing error problem caused by the elongation of the chain, so as to improve the overall performance and reliability of the engine.
[0007] The technical problem to be solved by the present invention is achieved through the following technical solutions:
[0008] The axle up and down groove at two ends embeds respectively in two guide rails up and down of being made up of the groove on the attachment piece, and the tooth on the attachment piece is meshed with tooth on upper sprocket wheel, the lower sprocket is meshed with tooth on upper sprocket wheel, and the tooth on lower sprocket is meshed with tooth on
[0009] Preferably, the above technical solution also includes: an oil channel, which includes a horizontal oil channel and a vertical oil channel, the horizontal oil channel is arranged on the lower bearing seat fixing block, and the vertical oil channel is arranged on the support plate, and the oil inlet flows into the guide rail groove after flowing through the vertical oil channel and the horizontal oil channel.
[0010] Preferably, the above technical solution further comprises: a threaded plug, which is arranged on a side of the horizontal oil channel away from the guide rail groove, and is used to block leakage points caused by problems in the punching process.
[0011] Preferably, in the above technical solution, one end of the bearing seat is a semicircular fork head, which is used to cooperate with the annular groove on the camshaft sprocket to form a sliding bearing; the other end of the bearing seat is a rectangular block, which is used to be inserted into the guide rail groove to achieve up and down sliding.
[0012] Preferably, in the above technical solution, the small hole on the upper bearing seat fixing block is positioned opposite to the small hole on the upper bearing seat and is fixed by the pull pin; the small hole on the lower bearing seat fixing block is positioned opposite to the small hole on the lower bearing seat and is fixed by the pull pin.
[0013] Preferably, in the above technical solution, a universal joint interface is reserved at the rear end of the camshaft sprocket, which is used to normally transmit the torque to the camshaft through the universal joint when the camshaft sprocket moves vertically, thereby ensuring the stable operation of the camshaft.
[0014] Preferably, in the above technical solution, the chain is a sleeve chain with a pitch of 9.525, the camshaft sprocket is a 30-tooth sprocket with a pitch of 9.525, and the secondary sprocket is a 20-tooth sprocket with a pitch of 9.525.
[0015] Preferably, in the above technical solution, the fixing bolt is an M8 bolt with a length of 16 mm; and the support plate is a steel structural member with a base wall thickness of 4 mm.
[0016] An engine comprises the above-mentioned engine floating tensioning timing system.
[0017] The above technical solution of the present invention has the following beneficial effects:
[0018] (1) The floating tensioning timing system can eliminate the tensioner, fixed rail and movable rail components, and is composed of a more versatile bearing seat, bearing seat fixing block and spring.
[0019] (2) Since the floating tension timing system can move up and down in the vertical direction and has the function of variable center distance, it can transfer the drastically changing load force to the spring and internal oil pressure for buffering, greatly reducing the tight side swing caused by speed and load, and increasing the system life.
[0020] (3) Since the floating tension timing system has a strong buffering and regulating effect, its internal initial spring force and dynamic oil pressure are lower than those of the ordinary timing system. Therefore, the dynamic tension during the entire movement process is also much lower than that of the ordinary timing system, which can greatly improve the NVH effect.
[0021] (4) Since the camshaft sprocket can move up and down, it can compensate for the wear and elongation of the chain and keep the timing state basically consistent with the initial state. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
[0023] Figure 1This is a schematic diagram of the engine floating tensioner timing system of the present application.
[0024] Figure 2 This is a cross-sectional view of the engine floating tensioner timing system of the present application.
[0025] Figure 3 This is an exploded diagram of the engine floating tensioner timing system of this application.
[0026] Figure 4 Schematic diagram of the connection between the support plate, bearing fixing block and bearing seat.
[0027] Figure 5 It is a schematic diagram of the connection between the support plate, the lower bearing seat fixing block, and the threaded plug.
[0028] Figure 6 Schematic diagram of the connection between the bearing seat and the camshaft sprocket.
[0029] Figure 7 A cross-sectional view of the bearing seat.
[0030] Figure 8 The diagram shows the state of the bearing seat and the bearing fixing block at the "top dead center".
[0031] Figure 9 This is a state diagram of the bearing seat and the bearing fixing block being at the "bottom dead center".
[0032] Figure 10A This is a schematic diagram of the threaded plug, lower bearing seat fixing block, lower bearing seat spring, and bearing seat before assembly.
[0033] Figure 10B This is a schematic diagram of the threaded plug, lower bearing seat fixing block, lower bearing seat spring and bearing seat after assembly.
[0034] Figure 11A This is a schematic diagram of the pull pin, camshaft sprocket, lower bearing seat and support plate before assembly.
[0035] Figure 11B Schematic diagram of the pull pin, camshaft sprocket, lower bearing seat and support plate after assembly.
[0036] Figure 12 Schematic diagram of the connection between the pull pin, camshaft sprocket, bearing seat and support plate.
[0037] In the figure: 1-fixing bolt, 2-support plate, 3-upper bearing seat spring, 4-bearing seat, 5-thread plug, 6-lower bearing seat spring, 7-upper bearing seat fixing block, 8-lower bearing seat fixing block, 9-chain, 10-camshaft sprocket, 11-pull pin, 12-secondary sprocket, 13-horizontal oil channel, 14-vertical oil channel, 15-guide rail groove. DETAILED DESCRIPTION
[0038] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention.
[0039] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods. The materials and reagents used are all commercially available unless otherwise specified. The equipment used in the experiments are all well known to those skilled in the art unless otherwise specified.
[0040] The floating tension timing system assembly of the present application is composed of a fixing bolt 1, a support plate 2, an upper bearing seat spring 3, a bearing seat 4, a threaded plug 5, a lower bearing seat spring 6, an upper bearing seat fixing block 7, a lower bearing seat fixing block 8, a chain 9, a camshaft sprocket 10, a pull pin 11, a secondary sprocket 12 and other parts. The pull pin 11 is used as an assembly process and needs to be pulled out after the assembly is completed. The following is a detailed description:
[0041] The fixing bolt 1 is an M8 bolt with a length of 16 mm, and is used to fix the upper bearing seat fixing block 7 and the lower bearing seat fixing block 8 on the support plate 2.
[0042] Support plate 2, a steel structural member with a base wall thickness of 4mm, forms a guideway with upper and lower bearing seat fixing blocks 7 and 8, allowing bearing seat 4 to slide up and down. Support plate 2 also features a 6mm-diameter vertical oil passage 14, which directs engine oil from the cylinder head oil passage into a guideway 15 formed by lower bearing seat fixing block 8 and support plate 2.
[0043] The upper bearing seat spring 3 is a stainless steel coil spring with a wire diameter of 1.2 mm, a median diameter of 6.5 mm, and 6 turns. Its nominal pitch is 3 mm and its stiffness coefficient is approximately 11.2 N / mm. It is installed between the bearing seat 4 and the upper bearing seat fixing block 7.
[0044] The bearing seat 4 is a steel structural member. One end of the bearing seat is a semicircular fork with a thickness of 8(0, -0.1) mm, which is used to fit into the circular groove with a width of 8(+0.1, 0) in the camshaft sprocket 10. The diameter of the semicircular fork of the bearing seat 4 is 20(+0.021, 0) mm, which is used to match the outer diameter of the circular groove of 20(-0.04, -0.055) in the camshaft sprocket (10) to form a sliding bearing. There is also an oil hole with a diameter of 1.5±0.1 mm on it, which can introduce the oil in the guide groove into the clearance of the sliding bearing.
[0045] The other end is a rectangular block with a thickness of 8 (0, -0.1) mm and a width of 10.5 (0, -0.1) mm. It can be inserted into the guide groove 15 formed by the upper and lower bearing seat fixing blocks 7, 8 and support plate 2. The guide groove 15 has a thickness of 8 (+0.1, 0) mm and a width of 10.5 (+0.1, 0) mm, so the bearing seat 4 can slide up and down in the guide groove. Because the upper and lower bearing seat fixing blocks 7, 8 are stepped grooves, when the rectangular end face of the bearing seat 4 contacts the stepped surfaces of the upper and lower bearing seat fixing blocks 7, 8, the dead center position is reached.
[0046] When the camshaft sprocket 10 is at top dead center, the upper bearing seat spring 3 is in a highly compressed state, with a spring height of 10 mm, while the lower bearing seat spring 6 is in a less compressed state, with a spring height of 20 mm. When the camshaft sprocket 10 is at bottom dead center, the upper bearing seat spring 3 is in a less compressed state, with a spring height of 20 mm, while the lower bearing seat spring 6 is in a highly compressed state, with a spring height of 10 mm. Therefore, the total travel of the camshaft sprocket 10 and the male bearing seat 4 is 10 mm.
[0047] The system's nominal state is when the camshaft sprocket 10 is in the neutral position, where both the upper and lower bearing seat springs 3 and 6 are 15mm long. Due to the different materials and pitches of the upper and lower bearing seat springs 3 and 6, the camshaft sprocket 10 is subjected to an upward thrust of approximately 80N, placing the chain in a taut state. This state represents the system's pre-tensioned state. When the engine is started, oil flows into the guide rail groove through the oil passages on the support plate 2 and the lower bearing seat fixing block 8, creating a pressure differential of approximately 2-3 bar inside and outside the groove. This further propels the lower convex bearing seat 4 upward, providing additional tension for the tensioned chain.
[0048] The thread plug 5, which is an M5, 6mm long countersunk screw, is installed on the left side of the horizontal oil passage 13 of the lower bearing seat fixing block 8 to block the leakage point caused by the drilling process problem.
[0049] The lower bearing seat spring 6 is a carbon steel coil spring with a wire diameter of 1.2 mm, a median diameter of 6.5 mm, and 6 turns. Its nominal pitch is 4 mm and its stiffness coefficient is approximately 12.4 N / mm. It is installed between the bearing seat 4 and the lower bearing seat fixing block 8.
[0050] The upper bearing seat fixing block 7 is a structural member with a base wall thickness of 4 mm. It forms a guide groove with the support plate 2. The guide groove is 8 (+0.1, 0) mm thick and 10.5 (+0.1, 0) mm wide. It also has a small hole with a diameter of 2 (+0.1, 0) mm for inserting the pull pin 11 to fix the position of the bearing seat 4.
[0051] The structure and function of the lower bearing seat fixing block 8 are similar to those of the upper bearing seat fixing block 7 , except that it has an additional oil passage for introducing the engine oil into the guide rail groove 15 .
[0052] The chain 9 is a 68-link bushing chain with a pitch of 9.525.
[0053] The camshaft sprocket 10 is a 30-tooth sprocket with a pitch of 9.525. A universal joint interface is reserved at its rear end. When the camshaft sprocket 10 moves in the vertical direction, the torque can be normally transmitted to the camshaft through the universal joint.
[0054] Pull pin 11, a steel wire with a diameter of 2(0, -0.1) mm, can be inserted into the 2(+0.1, 0) mm holes in the upper and lower bearing seat fixing blocks 7, 8, and bearing seat 4. It is used to secure the upper and lower bearing seat fixing blocks 7, 8, and bearing seat 4 relative to each other, facilitating installation. After the entire system is installed, pull pin 11 must be removed, allowing the upper and lower bearing seat springs 3, 6 to deform freely, pushing the bearing seat 4 to move freely, and completing the system pretensioning.
[0055] The secondary sprocket 12 is a 20-tooth sprocket with a pitch of 9.525.
[0056] Assembly instructions for the components of the engine floating tensioner timing system for this application:
[0057] (1) Screw the threaded plug 5 into the lower bearing seat fixing block 8; then place the lower bearing seat spring 6 and the bearing seat 4 into the guide groove in the lower bearing seat fixing block 8, and then press the bearing seat 4 in the vertical direction until its end face fits the stepped surface of the lower bearing seat fixing block 8, at which point it reaches the stop position; finally, insert the pull pin 11. At this point, the relative positions between these parts are fixed, and they can be assembled as a whole or as a small component in the future.
[0058] (2) Assemble the upper bearing seat spring 3, the bearing seat 4, the upper bearing seat fixing block 7 and the pull pin 11 together in the manner described in step (1) to form a new small assembly.
[0059] (3) Pass the round head of the pull pin 11 in step (1) through any one of the four holes on the edge of the camshaft sprocket 10, then clamp the camshaft sprocket 10 into the bearing seat 4, and finally pass the fixing bolt 1 through the support plate 2 and tighten it.
[0060] (4) Assemble the small components assembled in step (2) onto the support plate (2) in the same manner as in step (3).
[0061] 5. After installing the camshaft sprocket 10 and secondary sprocket 12, install the chain 9 onto both sprockets. Since the pull pin 11 has not yet been removed and the camshaft sprocket 10 is at bottom dead center, the center distance is 5mm less than the nominal center distance, making the chain 9 easy to install. After the chain is assembled, remove the pull pin 11, and the chain system is now pre-tensioned.
[0062] Working principle:
[0063] After assembly, the tension of the entire chain system is provided by the deformation of the upper bearing seat spring 3 and the lower bearing seat spring 6. Due to the different materials and initial pitches of the two springs, the system has a tension of approximately 80N. When the engine is started, engine oil enters the guide rail groove through the support plate 2 and the lower bearing seat fixing block 8. At this time, a pressure difference of 2-3 bar is generated between the inside and outside of the guide rail groove. This further pushes the bearing seat 4 and camshaft sprocket 10 upward, increasing the system tension.
[0064] During chain system operation, if the crankshaft speed suddenly decreases, the tension on the tight side decreases, and the bearing seat 4 and camshaft sprocket 10 move upward under the action of oil pressure and springs. This can increase the center distance of the system, compensate for the system tension, prevent excessive chain swing, reduce NVH levels, reduce swing wear, and prevent tooth skipping. If the crankshaft speed suddenly increases, the tension on the tight side increases, and the bearing seat 4 and camshaft sprocket 10 move downward under the action of chain tension, reducing the center distance of the system. Energy is absorbed by the spring and oil pressure buffer, which can reduce dynamic tension during operation and reduce wear.
[0065] The key technical point of the present invention lies in the structure of the bearing + spring + oil pressure introduced into the guide groove that can move up and down, so that the timing system can achieve the function of variable center distance, which can compensate for timing errors, reduce dynamic loads, increase service life, and reduce noise.
[0066] Although the present invention has been disclosed above by way of embodiments, they are not intended to limit the present invention. Any person skilled in the art may make various choices and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention is defined by the claims and their equivalents.
Claims
1. An engine floating tension timing system, characterized in that: include: A support plate (2), a bearing seat (4), a camshaft sprocket (10), a fixing block, a spring, a chain, a pull pin (11) and a secondary sprocket (12), wherein the semicircular fork of the bearing seat (4) cooperates with the annular groove of the camshaft sprocket (10) to form a sliding bearing, so that the camshaft sprocket (10) can move in the vertical direction; the fixing block includes an upper bearing seat fixing block (7) and a lower bearing seat fixing block (8), both of which are fixed to the support plate (2) by fixing bolts (1), and form a guide groove (15) with the support plate (2) for the bearing seat (4) to slide up and down; the spring includes an upper bearing seat spring The spring (3) and the lower bearing seat spring (6) are respectively arranged between the upper bearing seat fixing block (7), the lower bearing seat fixing block (8) and the bearing seat (4); the chain (9) is engaged with the camshaft sprocket (10) and the secondary sprocket (12) to realize power transmission and tension adjustment; the pull pin (11) is plug-connected with the upper bearing seat fixing block (7), the lower bearing seat fixing block (8) and the small hole on the bearing seat (4) to fix the relative positions of the upper bearing seat fixing block (7) and the lower bearing seat fixing block (8) and the bearing seat (4) during the assembly process.
2. The engine floating tensioner timing system according to claim 1, characterized in that: Also includes: An oil passage comprises a horizontal oil passage (13) and a vertical oil passage (14), wherein the horizontal oil passage (13) is arranged on the lower bearing seat fixing block (8), and the vertical oil passage (14) is arranged on the support plate (2), and the oil inlet flows into the vertical oil passage (14) and the horizontal oil passage (13) and is then introduced into the guide rail groove (15).
3. The engine floating tensioner timing system according to claim 2, characterized in that: Also includes: A threaded plug (5) is provided on a side of the horizontal oil passage (13) away from the guide rail groove (15) and is used to block leakage points caused by problems in the punching process.
4. The engine floating tensioner timing system according to claim 1, characterized in that: One end of the bearing seat (4) is a semicircular fork head, which is used to cooperate with the annular groove on the camshaft sprocket (10) to form a sliding bearing; the other end of the bearing seat (4) is a rectangular block, which is used to be inserted into the guide rail groove (15) to achieve up and down sliding.
5. The engine floating tensioner timing system according to claim 1, characterized in that: The small hole on the upper bearing seat fixing block (7) is positioned opposite to the small hole on the upper bearing seat (4) and is fixed by the pull pin (11); the small hole on the lower bearing seat fixing block (8) is positioned opposite to the small hole on the lower bearing seat (4) and is fixed by the pull pin (11).
6. The engine floating tensioner timing system according to claim 1, characterized in that: A universal joint interface is reserved at the rear end of the camshaft sprocket (10), which is used to normally transmit torque to the camshaft through the universal joint when the camshaft sprocket (10) moves vertically, thereby ensuring stable operation of the camshaft.
7. The engine floating tensioner timing system according to claim 1, characterized in that: The chain (9) is a sleeve chain with a pitch of 9.525, the camshaft sprocket (10) is a 30-tooth sprocket with a pitch of 9.525, and the secondary sprocket (12) is a 20-tooth sprocket with a pitch of 9.
525.
8. The engine floating tensioner timing system according to claim 1, characterized in that: The fixing bolt (1) is an M8 bolt with a length of 16 mm; the support plate (2) is a steel structural member with a base wall thickness of 4 mm.
9. An engine, characterized in that: The engine floating tensioning timing system comprises the engine floating tensioning timing system according to any one of claims 1 to 8.