An eccentric adjustment assembly for a tensioner wheel support

Abstract

The utility model provides a kind of eccentricity adjusting assembly of tensioner support, belong to transmission auxiliary device technical field, the eccentricity adjusting assembly of tensioner support includes support seat, eccentric shaft sleeve, tensioner axle and tensioner body, support seat is used to be fixed on engine body, eccentric shaft sleeve is movably installed on support seat, one end of tensioner axle is fixed on eccentric shaft sleeve, and tensioner body is rotatably installed on tensioner axle by rolling bearing;Support seat is provided with a cylindrical mounting hole along its axial direction, eccentric shaft sleeve is arranged in mounting hole, eccentric shaft sleeve rotates around its own axis, and then drive tensioner axle rotates around the axis of eccentric shaft sleeve;The utility model can solve the problem that existing tensioner is easy to loosen after adjusting, leading to the tension of belt drive system difficult to accurately and stably control, influence engine transmission efficiency and component life.

Description

Technical Field

[0001] This utility model belongs to the technical field of transmission auxiliary devices, and specifically relates to an eccentric adjustment component supported by a tensioner wheel. Background Technology

[0002] In modern internal combustion engines and various mechanical transmission systems, belt drives are widely used due to their advantages such as simple structure, smooth transmission, and low noise. Especially in automotive engine accessory drive systems (such as generators, air conditioning compressors, and water pumps), synchronous belts or multi-ribbed belts are the primary transmission medium. However, belts elongate during long-term operation, and due to manufacturing tolerances or installation errors, precise adjustment and maintenance of belt tension are necessary to ensure transmission efficiency and belt lifespan. Existing belt tension adjustment structures mainly include two methods: bolt sliding adjustment and eccentric pulley adjustment. Bolt sliding adjustment is typically achieved through a long groove and one or more locking bolts. Operation requires loosening the locking bolts, moving the tensioning pulley to a new position, and then retightening. This method has low adjustment accuracy, is cumbersome, and is prone to loosening due to insufficient locking force in vibrating environments. Another common eccentric pulley adjustment structure usually involves complex worm gear mechanisms or multiple linked components to achieve eccentric rotation. While it can achieve relatively precise adjustment, its structure is complex, manufacturing costs are high, and the excessive number of components may lead to decreased reliability. In particular, many existing eccentric adjustment components, after tension adjustment, suffer from positioning and locking mechanisms that cannot guarantee absolute stability under long-term engine vibration and high-load operation. This can easily lead to slight drift in the position of the tensioner pulley, affecting the accuracy of belt tension and potentially causing serious problems such as belt slippage, excessive wear, or tooth skipping. Therefore, there is an urgent need for a tensioner pulley support eccentric adjustment component that is simple in structure, precise in adjustment, easy to operate, and has reliable locking. Utility Model Content

[0003] In view of this, the present invention provides an eccentric adjustment component for tensioner support, which can solve the problem that existing tensioners are prone to loosening after adjustment, making it difficult to accurately and stably control the tension of the belt drive system, thus affecting the transmission efficiency of the engine and the life of the components.

[0004] This utility model is implemented as follows:

[0005] This utility model provides an eccentric adjustment assembly for a tensioner support, used to be installed on an engine body and to tension a drive belt. It includes a support base, an eccentric bushing, a tensioner shaft, and a tensioner body for rotating the tensioner. The support base is fixed to the engine body, the eccentric bushing is movably mounted on the support base, one end of the tensioner shaft is fixed to the eccentric bushing, and the tensioner body is rotatably mounted on the tensioner shaft via a rolling bearing. The support base has a cylindrical mounting hole along its axial direction, and the eccentric bushing passes through the mounting hole. The eccentric bushing rotates around its own axis, thereby driving the tensioner shaft to rotate around the axis of the eccentric bushing. The support base, eccentric bushing, and tensioner shaft are connected and fixed by bolts or screws, and are used to adjust the center position of the tensioner body relative to the support base. The outer circumferential surface of the eccentric bushing is in close contact with the inner circumferential surface of the mounting hole of the support base.

[0006] The technical advantages of the eccentric adjustment assembly for a tensioner support provided by this utility model are as follows: By constructing an eccentric adjustment assembly for a tensioner support through a support base, an eccentric sleeve, a tensioner shaft, and a tensioner body, precise and convenient adjustment of the transmission belt tension is achieved. The support base provides a stable foundation for firmly mounting the entire assembly to the engine block. The eccentric sleeve, with its unique eccentric structure design, effectively changes the center position of the tensioner shaft when rotating within the mounting hole of the support base, thereby changing the contact position between the tensioner body and the belt, and thus adjusting the belt tension. The eccentric sleeve ensures stability and positioning accuracy during rotation through a tight fit between its outer circumferential surface and the inner circumferential surface of the mounting hole. Furthermore, the bolt or screw connection facilitates locking after installation and adjustment, effectively preventing positional drift or loosening of the tensioner during engine operation, ensuring the reliability and long-term stability of the belt drive, greatly simplifying engine maintenance and tension adjustment operations after belt replacement, and improving operational efficiency.

[0007] Based on the above technical solution, the eccentric adjustment component of the tension wheel support of this utility model can be further improved as follows:

[0008] The eccentric bushing has a length along its axis, and the tensioner shaft has an axial protrusion length on the eccentric bushing, which is greater than the length of the eccentric bushing along its axis.

[0009] The beneficial effects of the above-mentioned improvement scheme are as follows: By designing the axial protrusion length of the tensioner shaft to be greater than the length of the eccentric bushing along its axial direction, it effectively ensures that the tensioner shaft has sufficient protrusion for mounting the tensioner body and necessary bearings. It also ensures that a certain axial clearance is maintained between the tensioner body and the eccentric bushing and support seat, avoiding interference or friction between the tensioner body and the support seat or eccentric bushing during rotation, thus improving the smoothness and reliability of rotation. This dimensional design allows the tensioner body to be stably installed and operated, while providing good axial support for the assembly, enhancing the overall structural stability, ensuring continuous and stable operation of the tensioner under high-speed or high-load conditions, and extending the service life of the assembly.

[0010] Furthermore, the length of the mounting hole of the support base along its axial direction is less than the length of the eccentric bushing along its axial direction. The eccentric bushing has an end face at each end, and the two end faces extend out of the two sides of the mounting hole respectively.

[0011] The beneficial effects of the above-mentioned improved design are as follows: By setting the length of the mounting hole of the support base along its axial direction to be less than the length of the eccentric bushing along its axial direction, the two end faces of the eccentric bushing can extend out from both sides of the mounting hole. This structural design provides two advantages. First, the extended end faces facilitate the operator's use of a wrench to clamp and rotate the eccentric bushing, thereby achieving eccentric adjustment of the tensioner position and improving the convenience of the adjustment operation. Second, the extended end faces provide a potential contact surface for the sealing and dust prevention of the component, helping to prevent external contaminants from entering the mating clearance between the mounting hole and the eccentric bushing, protecting the internal fitting accuracy and lubrication condition, and enhancing the durability and reliability of the component in harsh environments.

[0012] Furthermore, the end face of the eccentric bushing is set with a hexagonal outer contour shape, and the hexagonal shape is used to be clamped by a wrench or other tools to drive the eccentric bushing to rotate.

[0013] The beneficial effects of adopting the above-mentioned improved scheme are as follows: By setting the end face of the eccentric bushing to a hexagonal outer contour shape, a standard and efficient tool interface is provided for the tension adjustment of the tension wheel. The hexagonal shape is a well-known, easy-to-manufacture, and high-strength tool fit. Operators can use a standard hex wrench or other matching tools to apply reliable torque to the eccentric bushing, thereby driving it to rotate within the mounting hole of the support, achieving precise adjustment of the tension wheel position. This design is more universal and convenient than the cylindrical end face method, which requires special tools for clamping, greatly simplifying the maintenance and adjustment process, improving the efficiency of on-site operations, and avoiding potential damage to components due to tool slippage, ensuring the accuracy and reliability of the adjustment process.

[0014] Furthermore, one end of the support has a flange extending circumferentially around the mounting hole, the thickness of which is less than the thickness of the rest of the support.

[0015] The beneficial effects of the above-mentioned improvement scheme are as follows: By providing a flange extending circumferentially around the mounting hole at one end of the support base, and with the flange thickness being less than the thickness of other parts of the support base, the eccentric bushing can be axially positioned and limited. The flange can constrain the movement of the eccentric bushing along the axial direction from one side, ensuring the correct axial position of the eccentric bushing within the mounting hole and preventing movement due to vibration or axial force during operation. Simultaneously, the smaller thickness design helps reduce the overall weight of the component and, without sacrificing necessary structural strength, provides space for the installation or clearance of other adjacent components, achieving an optimized balance between structural compactness and functionality, and contributing to the lightweight and integrated design of the component.

[0016] Furthermore, the eccentric bushing has an outer circumferential surface, on which one or more circular grooves are provided along the circumferential direction, and the cross-sectional shape of the circular grooves is semi-circular.

[0017] The beneficial effects of the above-mentioned improvement scheme are as follows: By providing one or more circular grooves along the circumferential direction on the outer circumferential surface of the eccentric bushing, with the cross-sectional shape of the circular grooves being semi-circular, additional functions are provided for the lubrication and dust prevention of the component. The circular grooves can serve as oil reservoirs or channels for containing grease. When the eccentric bushing rotates in conjunction with the mounting hole of the support, it helps to evenly distribute and retain the lubricating medium, reducing friction between the mating surfaces, lowering wear, and thus improving the smoothness of the component's rotation and its service life. Furthermore, these grooves can also be used to install O-rings or lip seals to enhance the component's dust and water resistance, effectively preventing external contaminants from entering the mating gap. This is particularly suitable for applications exposed to dusty or humid environments, greatly improving the reliability and durability of the component.

[0018] Furthermore, the support base and the eccentric bushing are connected by a fastener for locking and positioning. The fastener passes through the wall of the support base and the wall of the eccentric bushing to fix the rotational position of the eccentric bushing relative to the support base.

[0019] The beneficial effects of the above-mentioned improved scheme are as follows: By setting a fastener for locking and positioning between the support base and the eccentric bushing, and ensuring that the fastener passes through the support base wall and the eccentric bushing wall, reliable locking of the tensioner adjustment position is achieved. After the eccentric adjustment of the tensioner is completed and the required belt tension is achieved, the operator tightens the fastener so that one end or the main body of the fastener passes through or presses against the eccentric bushing, thereby preventing the eccentric bushing from rotating around its own axis. This locking mechanism can resist the vibration and torque generated during engine operation, ensuring that the position of the tensioner remains unchanged during long-term use, avoiding belt tension slack or over-tension, ensuring the reliable operation of the engine transmission system, and simplifying subsequent maintenance work.

[0020] Furthermore, the end of the tensioner shaft extending from the eccentric bushing has a circular step for mounting the tensioner body, and the diameter of the circular step is larger than the diameter of other parts of the tensioner shaft.

[0021] The beneficial effects of the above-mentioned improvement scheme are as follows: By setting one end of the tensioner shaft extending from the eccentric bushing as a circular step for mounting the tensioner body, and with the diameter of the circular step being larger than the diameter of other parts of the tensioner shaft, a clear and stable reference is provided for the axial positioning and installation of the tensioner body. The circular step can form a reliable contact surface with the end face of the outer or inner ring of the rolling bearing inside the tensioner body, thereby providing axial support and positioning for the tensioner body, ensuring that the tensioner maintains the correct axial position during operation and avoiding axial movement. This design simplifies the installation process of the tensioner body, while improving its operational stability, ensuring correct alignment between the belt and the tensioner, reducing belt misalignment and wear, and extending the service life of the belt and the tensioner.

[0022] Furthermore, the support base is made of cast aluminum alloy, while the eccentric bushing and tensioner shaft are made of carbon steel.

[0023] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: By selecting cast aluminum alloy as the material for the support base and carbon steel as the material for the eccentric bushing and tensioner shaft, an optimized combination of lightweight, strength, and cost-effectiveness is achieved for the component. Cast aluminum alloy has the characteristics of low density and light weight, and its use in manufacturing the support base can effectively reduce the weight of the entire component, which is beneficial to the lightweight design of the engine and the improvement of fuel economy. At the same time, aluminum alloy also has good corrosion resistance. Carbon steel has high strength, hardness, and wear resistance, making it very suitable for manufacturing components that bear high stress and require high fitting precision, such as eccentric bushings and tensioner shafts. This ensures the structural integrity and dimensional stability of these key components under long-term high-load operation, guaranteeing the long-term reliable operation of the component.

[0024] Furthermore, the tensioner body is made of polyamide plastic or glass fiber reinforced polyamide plastic.

[0025] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: By selecting polyamide plastic or glass fiber reinforced polyamide plastic as the material for the tensioner body, the performance and cost of the tensioner body are optimized. Polyamide plastic has the characteristics of self-lubrication, wear resistance, and fatigue resistance, which can effectively reduce friction and noise between the tensioner and the belt, while also having good heat resistance, making it suitable for the high-temperature environment of the engine compartment. Using glass fiber reinforced polyamide plastic can further improve the mechanical strength, rigidity, and heat deformation resistance of the tensioner body, making it less prone to deformation under high load and high-speed operating conditions, thus ensuring the stability and reliability of the transmission system. In addition, the plastic tensioner body has lower manufacturing costs and more flexible molding capabilities, which is conducive to mass production and improves the market competitiveness of the product.

[0026] Compared with existing technologies, the eccentric adjustment assembly for a tensioner support provided by this utility model offers the following advantages: It provides a compact, precise, and reliable belt tension adjustment structure through a support base, eccentric sleeve, tensioner shaft, and tensioner body. The support base serves as a fixed base, and the eccentric sleeve, through its eccentric design, can precisely change the center position of the tensioner shaft during rotation, thereby achieving stepless adjustment of the belt tension. The mounting holes of the eccentric sleeve and the support base utilize a tight-fitting cylindrical surface contact, ensuring the smoothness of the adjustment process and the stability of the adjusted position. The hexagonal end face of the eccentric sleeve facilitates adjustment using standard tools, improving operational convenience. Fasteners are provided between the support base and the eccentric sleeve for locking and positioning, ensuring reliable locking of the adjusted tension position. This effectively resists engine vibration and operating loads, avoiding the loosening problems that may occur with threaded locking in traditional adjustment structures, and greatly enhancing the reliability and long-term stability of the transmission system. By designing the support base as a cast aluminum alloy, the component achieves lightweight construction, while the eccentric bushing and tensioner shaft are made of carbon steel, ensuring the strength and wear resistance of key load-bearing components. The tensioner body is made of polyamide plastic or glass fiber reinforced polyamide plastic, reducing manufacturing costs and providing good wear resistance and noise reduction performance. This design optimizes the material selection, shape, and dimensional matching of the components, resulting in a highly integrated, highly precise, highly reliable locking, and durable assembly. It effectively solves the core technical problems of complex adjustment structures, low positioning accuracy, and easy loosening in existing technologies, improving the efficiency and service life of the engine accessory transmission system. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A schematic diagram of the structure of an eccentric adjustment component supported by a tensioner wheel;

[0029] Figure 2 A top view of an eccentric adjustment assembly supported by a tensioner pulley;

[0030] Figure 3 A front view of an eccentric adjustment assembly supported by a tensioner wheel;

[0031] The attached diagram lists the components represented by each number as follows:

[0032] 10. Support base; 11. Eccentric bushing; 12. Tensioner shaft; 13. Tensioner body; 14. End face; 15. Flange; 16. Fastener; 17. Circular step. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings.

[0034] like Figures 1-3 The diagram illustrates an embodiment of an eccentric adjustment assembly for a tensioner support provided by this utility model. In this embodiment, it is used to install on the engine body and tension the drive belt. The assembly includes a support base 10, an eccentric bushing 11, a tensioner shaft 12, and a tensioner body 13 for rotating the tensioner. The support base is fixed to the engine body, the eccentric bushing is movably mounted on the support base, one end of the tensioner shaft is fixed to the eccentric bushing, and the tensioner body is rotatably mounted on the tensioner shaft via a rolling bearing. The support base has a cylindrical mounting hole along its axial direction, and the eccentric bushing passes through the mounting hole. The eccentric bushing rotates around its own axis, thereby driving the tensioner shaft to rotate around the axis of the eccentric bushing. The support base, eccentric bushing, and tensioner shaft are connected and fixed by bolts or screws, and are used to adjust the center position of the tensioner body relative to the support base. The eccentric bushing's outer circumferential surface is in close contact with the inner circumferential surface of the mounting hole of the support base.

[0035] In the above technical solution, the eccentric bushing has a length along its axial direction, and the tensioner shaft has an axial protrusion length on the eccentric bushing, which is greater than the length of the eccentric bushing along its axial direction.

[0036] Furthermore, in the above technical solution, the length of the mounting hole of the support base along its axial direction is less than the length of the eccentric bushing along its axial direction. Each end of the eccentric bushing has an end face 14, and the two end faces extend out of both sides of the mounting hole.

[0037] Furthermore, in the above technical solution, the end face of the eccentric bushing is set as a hexagonal outer contour shape, and the hexagonal shape is used to be clamped by a wrench or other tools to drive the eccentric bushing to rotate.

[0038] Furthermore, in the above technical solution, one end of the support has a flange 15 extending circumferentially around the mounting hole, and the thickness of the flange is less than the thickness of other parts of the support.

[0039] Furthermore, in the above technical solution, the eccentric bushing has an outer circumferential surface, and one or more circular grooves are provided on the outer circumferential surface along the circumferential direction. The cross-sectional shape of the circular grooves is semi-circular.

[0040] Furthermore, in the above technical solution, the support base and the eccentric bushing are connected by a fastener 16 for locking and positioning. The fastener passes through the support base wall and the eccentric bushing wall to fix the rotational position of the eccentric bushing relative to the support base.

[0041] Furthermore, in the above technical solution, the end of the tension wheel shaft extending from the eccentric bushing has a circular step 17 for mounting the tension wheel body, and the diameter of the circular step is larger than the diameter of other parts of the tension wheel shaft.

[0042] Furthermore, in the above technical solution, the material of the support base is cast aluminum alloy, and the materials of the eccentric bushing and the tension wheel shaft are carbon steel.

[0043] Furthermore, in the above technical solution, the material of the tensioner body is polyamide plastic or glass fiber reinforced polyamide plastic.

[0044] The method of using this utility model is as follows: It mainly includes the steps of fixing the support base, installing the eccentric bushing and the tensioner body, adjusting the tension, and finally locking. First, the support base is firmly fixed to the predetermined position on the engine body through the bolt holes of its mounting structure, ensuring the accuracy of its position and the stability of the installation. Second, the eccentric bushing is inserted into the cylindrical mounting hole of the support base from one end until both end faces of the eccentric bushing protrude from both sides of the mounting hole, with the eccentric bushing tightly fitting the inner circumferential surface of the mounting hole. Then, the roller bearing is press-fitted into the center hole of the tensioner body, and the tensioner body and its bearing are then fitted onto the end of the tensioner shaft that protrudes from the eccentric bushing. An axial fastener (such as a nut and washer) is used to fix it to the circular step of the tensioner shaft, ensuring that the tensioner body can rotate freely around the tensioner shaft while having reliable axial positioning. Next, adjust the belt tension. First, place the drive belt onto all the drive pulleys and the tensioner body. Then, using a wrench or other suitable tool, the operator holds the eccentric bushing protruding from the hexagonal end face of the support and slowly rotates it. As the eccentric bushing rotates, the center position of the tensioner shaft will shift eccentrically, thus pushing the tensioner body to apply tension to the belt. The operator should use a professional tension measuring tool to monitor the belt tension in real time until it reaches the value specified by the engine manufacturer. Finally, after the tension adjustment is complete, the operator should immediately use a fastener (such as a screw or threaded pin) to pass through the pre-drilled hole in the support wall and screw it into or press it against the outer wall of the eccentric bushing to securely lock it in its current angular position, preventing any rotation during engine operation. After locking, check again to ensure the belt tension still meets the requirements and confirm that all fasteners are tightened to the specified torque. The entire process utilizes the rotation of the eccentric bushing to achieve stepless adjustment, which has high adjustment accuracy, is simple to operate, and the final fastener locking mechanism ensures the long-term stability of the tension position.

[0045] The following is a specific embodiment 1 of this utility model: The eccentric adjustment assembly of the tensioner support in this embodiment includes a support base, an eccentric bushing, a tensioner shaft, and a tensioner body. The support base is made of cast aluminum alloy (such as an Al-Si alloy) and has a cylindrical mounting hole extending along its axial direction, with a length of approximately 25 mm. A thin flange, approximately 5 mm thick, is provided on the side of the support base near the engine body for axial positioning of the eccentric bushing. The eccentric bushing is made of known carbon steel (such as 45# steel) and has a length of approximately 30 mm along its axial direction, greater than the length of the mounting hole in the support base. The outer circumference diameter of the eccentric bushing and the inner circumference diameter of the mounting hole are designed for a tight fit of H7 / h6, with an eccentricity of 10 mm. Both ends of the eccentric bushing extend out of the mounting holes in the support base, with one end face machined into a standard hexagon with opposite sides of 22 mm for wrench clamping. The tensioner shaft is also made of carbon steel and is press-fitted and welded to the eccentric bushing. The axial protrusion length of the tensioner shaft is 40mm, which is longer than the length of the eccentric bushing. The protruding end of the tensioner shaft has a 15mm diameter circular step for mounting the tensioner body. The tensioner body is injection-molded from polyamide 66 plastic with 30% glass fiber content and contains an embedded rolling bearing. The tensioner body is rotatably mounted on the tensioner shaft via the bearing and secured to the circular step by an M10 nut and washer. A threaded hole is provided on the side wall of the support for mounting an M8 fastening screw. This screw passes through the support wall and presses against the outer circumferential surface of the eccentric bushing, thereby locking the rotational position of the eccentric bushing. This embodiment allows for stepless adjustment of the center position of the tensioner body within a maximum eccentricity range of 10mm by rotating the eccentric bushing, thereby achieving precise control of the transmission belt tension. The hexagonal end face facilitates tool operation, and the fastening screw ensures reliable locking of the adjusted position. It is suitable for tension adjustment of timing belts or accessory drive belts in automobile engines.

[0046] The following is another specific embodiment 2 of this utility model: This embodiment is based on embodiment 1, with upgrades to the surface shape of the eccentric bushing and the structure of the support seat. In embodiment 1, the eccentric bushing has a smooth outer circumferential surface. In this embodiment, four circular grooves are evenly arranged circumferentially on the outer circumferential surface of the eccentric bushing. The cross-section of the circular grooves is a semicircle with a radius of 1mm. These grooves are used to store grease to improve the smoothness of the eccentric bushing during rotation adjustment in the mounting hole of the support seat and reduce the wear of the mating surfaces. The material of the support seat is still cast aluminum alloy, but the wall thickness of the position on the support seat used to install the locking screw is increased to 10mm, and the locking screw is changed from the M8 ordinary screw in embodiment 1 to an M8 fastening bolt with a positioning tapered end. After the tapered bolt is screwed into the support seat, its tapered end can more accurately push or press the eccentric bushing, providing a more uniform locking force, further enhancing the vibration resistance and loosening resistance of the adjustment position. Furthermore, the connection between the tensioner shaft and the eccentric bushing has been changed from welding to a high-strength interference fit press fitting. This improvement reduces thermal stress during manufacturing and enhances the connection strength and concentricity between the tensioner shaft and the eccentric bushing. This embodiment improves the smoothness and wear resistance of adjustment through lubrication grooves and enhances the reliability and stability of positioning through tapered end locking bolts.

[0047] The following is another specific embodiment 3 of this utility model: This embodiment is based on Embodiment 1, with improvements made to the materials and surface treatment of the components. The material of the support base is still cast aluminum alloy, but it has undergone anodizing treatment, forming a hard and corrosion-resistant oxide film on the surface, enhancing its durability in humid and corrosive environments. The materials of the eccentric bushing and the tensioner shaft have been upgraded from carbon steel to known alloy steel (such as 40Cr), and the surface has been integrally nickel-plated. The nickel plating layer has excellent wear resistance and corrosion resistance, especially improving the wear resistance of the mating surface between the eccentric bushing and the support base mounting hole, further extending the service life of the adjustment mechanism. The material of the tensioner body is still glass fiber reinforced polyamide plastic, but a metal bushing has been added to its bearing seat hole. The metal bushing mates with the circular step of the tensioner shaft, replacing the direct use of plastic bearing seat holes. This design significantly improves the bearing installation rigidity and load-bearing capacity of the tensioner body under high-speed rotation and high load, reducing the risk of wear and thermal deformation. Meanwhile, the fastener locking screw in this embodiment is an M8 screw with anti-loosening threads (such as nylon locking threads), which further improves the reliability of locking and prevents the screw itself from loosening during severe vibration.

[0048] The following is another specific application scenario of this utility model, embodiment 4. This embodiment is applied to the belt drive system of agricultural machinery such as tractor engines, including a cast iron support base, a stainless steel eccentric bushing, an alloy steel tensioner shaft, and a wear-resistant rubber-coated tensioner body, as detailed below: Since the working environment of agricultural machinery is usually harsh, including high dust, high humidity, and significant vibration, the components in this embodiment emphasize durability and reliability in material selection and structural design. The support base is made of known ductile iron, which has excellent vibration absorption and high strength, better adapting to the operating environment of tractor engines. Its mounting hole length is 40mm. The eccentric bushing and tensioner shaft are made of known stainless steel (such as 304 stainless steel) to ensure excellent corrosion resistance in humid and outdoor environments. The eccentricity of the eccentric bushing is set to 15mm to accommodate the large tension adjustment requirements of agricultural machinery drive belts. The two end faces of the eccentric bushing are also hexagonal, but the size is increased to 30mm to facilitate adjustment by the operator wearing gloves. The tensioner body is made of oil-resistant and wear-resistant synthetic rubber coated on a metal wheel core. The rubber coating provides greater friction and better cushioning to adapt to belt operation in muddy, dusty, and other environments. The tensioner body is mounted on the tensioner shaft via a high-load rolling bearing. The diameter of the circular step on the tensioner shaft is 25mm. In this embodiment, a locking pin with a protective cover is installed on the support base. The locking pin passes through pre-set mating holes on the support base wall and the eccentric bushing wall. There are six mating holes arranged circumferentially, one every 60°, providing six preset tension positions for segmented and precise adjustment. The protective cover prevents dust and moisture from entering the locking mechanism. During operation, the operator first determines the required tension range, then rotates the eccentric bushing to the nearest preset hole, inserts the locking pin, and closes the protective cover, thus achieving quick and reliable positioning and locking. This design, while ensuring adjustment accuracy, greatly enhances the durability and dust and water resistance of the components under harsh working conditions.

[0049] Specifically, the principle of this utility model is as follows: The eccentric adjustment component of the tensioner support of this utility model mainly utilizes the geometric principle that when the eccentric bushing rotates relative to the support base, the center position of the tensioner shaft it is mounted on will shift along a circular trajectory. Specifically, the support base is fixed to the engine body, serving as the reference for the entire component. The geometric center of the eccentric bushing has a certain eccentricity with the center of the mounting hole of the support base, while the center of the tensioner shaft is coaxial with the geometric center of the eccentric bushing. When the operator uses a tool to drive the eccentric bushing to rotate within the mounting hole of the support base through the hexagonal interface at the end of the eccentric bushing, due to the eccentricity, the center of the tensioner shaft, that is, the mounting center of the tensioner body, will rotate around the center of the mounting hole of the support base, thereby changing the contact position between the tensioner body and the transmission belt, achieving stepless adjustment of the transmission belt tension. This mechanism of achieving eccentric adjustment through the rotation of the eccentric bushing greatly simplifies the structure and improves the accuracy and convenience of adjustment. After adjustment, the support base and the eccentric bushing are locked together by fasteners. The fasteners pass through the support base wall and press or lock the eccentric bushing. Friction or direct limiting is used to prevent the eccentric bushing from continuing to rotate, thereby accurately fixing the position of the tension wheel. It can remain stable even under severe vibration conditions, ensuring the long-term reliability of the tension force.

Claims

1. An eccentric adjustment assembly for a tensioner pulley support, used for mounting on an engine body and tensioning a drive belt, characterized in that, The device includes a support base, an eccentric bushing, a tensioner shaft, and a tensioner body for rotating the tensioner. The support base is fixed to the engine body, the eccentric bushing is movably mounted on the support base, one end of the tensioner shaft is fixed to the eccentric bushing, and the tensioner body is rotatably mounted on the tensioner shaft via rolling bearings. The support base has a cylindrical mounting hole along its axial direction, the eccentric bushing passes through the mounting hole, and the eccentric bushing rotates around its own axis, thereby driving the tensioner shaft to rotate around the axis of the eccentric bushing. The support base, eccentric bushing, and tensioner shaft are connected and fixed by bolts or screws, which are used to adjust the center position of the tensioner body relative to the support base. The eccentric bushing's outer circumferential surface is in close contact with the inner circumferential surface of the mounting hole of the support base.

2. The eccentric adjustment assembly for a tensioner pulley support according to claim 1, characterized in that, The eccentric bushing has a length along its axis, and the tensioner shaft has an axially protruding length on the eccentric bushing, which is greater than the length of the eccentric bushing along its axis.

3. The eccentric adjustment assembly for a tensioner pulley support according to claim 2, characterized in that, The length of the mounting hole of the support base along its axis is less than the length of the eccentric bushing along its axis. The eccentric bushing has an end face at each end, and the two end faces extend out of the two sides of the mounting hole.

4. The eccentric adjustment assembly for a tensioner pulley support according to claim 3, characterized in that, The end face of the eccentric bushing is set with a hexagonal outer contour shape. The hexagonal shape is used to be clamped by a wrench or other tools to drive the eccentric bushing to rotate.

5. The eccentric adjustment assembly for a tensioner pulley support according to claim 4, characterized in that, One end of the support has a flange that extends circumferentially around the mounting hole, and the thickness of the flange is less than the thickness of the rest of the support.

6. The eccentric adjustment assembly for a tensioner pulley support according to claim 5, characterized in that, The eccentric bushing has an outer circumferential surface, and one or more circular grooves are provided on the outer circumferential surface along the circumferential direction. The cross-sectional shape of the circular grooves is semi-circular.

7. The eccentric adjustment assembly for a tensioner pulley support according to claim 6, characterized in that, The support base and the eccentric bushing are connected by a fastener for locking and positioning. The fastener passes through the wall of the support base and the wall of the eccentric bushing to fix the rotational position of the eccentric bushing relative to the support base.

8. The eccentric adjustment assembly for a tensioner pulley support according to claim 7, characterized in that, The end of the tensioner shaft extending from the eccentric bushing has a circular step for mounting the tensioner body, and the diameter of the circular step is larger than the diameter of other parts of the tensioner shaft.

9. The eccentric adjustment assembly for a tensioner pulley support according to claim 8, characterized in that, The support base is made of cast aluminum alloy, while the eccentric bushing and tension wheel shaft are made of carbon steel.

10. The eccentric adjustment assembly for a tensioner pulley support according to claim 9, characterized in that, The tensioner body is made of polyamide plastic or glass fiber reinforced polyamide plastic.

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