Automatic tensioner with adjustable output torque

Abstract

The present invention provides an automatic tensioner with adjustable output torque, comprising a base, a first torque spring, a first spring adjustment assembly, a second torque spring, a second spring adjustment assembly, a pivot, a tensioning arm assembly, and a tensioning wheel assembly. The tensioning wheel assembly is mounted at one end of the tensioning arm assembly, and the base is mounted at the other end of the tensioning arm assembly. The first torque spring and the second torque spring are respectively arranged at upper and lower sides within the base. The first spring adjustment assembly is connected within the first sleeve of the tensioning arm assembly, and its lower end extends into the base and is capable of contacting the upper end of the first torque spring. The second spring adjustment assembly is connected within the second sleeve, and its upper end extends into the base and is capable of contacting the lower end of the second torque spring. The present invention has a simple and compact structure. By combining and separating multiple torque springs to switch the spring stiffness of the tensioner, the output torque can be freely adjusted, thereby expanding the application range of the tensioner and extending the service life of the tensioner.

Description

Technical Field

[0001] The present invention relates to the technical field of tensioners, and in particular to an automatic tensioner with adjustable output torque. Background Art

[0002] Tensioners are primarily used in automotive belt drive systems to maintain belt tension and prevent belt slippage, ensuring smooth transmission of engine power to accessories. Automatic tensioners primarily consist of an energy storage element, which continuously maintains belt tension, and a damping element, which attenuates belt vibration and improves accessory system stability. The energy storage element is typically a spring, either a coil spring or a leaf spring. A friction-type automatic tensioner generates damping through the interaction between components, such as frictional damping generated by sliding between components.

[0003] Traditional tensioners use a fixed spring stiffness, resulting in a fixed range of variation in their output torque, limiting the tensioner's application and service life. For example, patent application number CN106838165 discloses an automatic tensioner equipped with a symmetrically arranged damping device. The automatic tensioner primarily consists of a base, a tensioning arm, a tensioning pulley, a coil spring, and a damping element. This invention uses a coil spring to control the output torque. However, the torque output range is limited by the coil spring's own performance parameters, and can only meet a certain torque range, limiting its applicability. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: in order to overcome the shortcomings of the prior art tensioner in that the output torque range is limited, which leads to limited application range and service life, the present invention provides an automatic tensioner with adjustable output torque.

[0005] The technical solution adopted by the present invention to solve its technical problem is: an automatic tensioner with adjustable output torque, including a base, a first torque spring, a first spring adjustment assembly, a second torque spring, a second spring adjustment assembly, a pivot, a tensioning arm assembly and a tensioning wheel assembly, wherein:

[0006] The tensioning arm assembly comprises a tensioning wheel assembly mounting portion and a C-shaped support portion, and the tensioning wheel assembly mounting portion and the C-shaped support portion are respectively arranged at both ends of the tensioning arm assembly, the tensioning wheel assembly is mounted on the tensioning wheel assembly mounting portion, the upper end of the C-shaped support portion is provided with a first sleeve, and the lower end is provided with a second sleeve, the base is connected between the first sleeve and the second sleeve, the pivot is axially rotatably connected in the base, and the upper and lower ends extend out of the base and are respectively fixedly connected to the first sleeve and the second sleeve;

[0007] The base is a double-layer coaxial cylindrical structure, including a coaxially arranged inner ring and outer ring, and the inner ring and the outer ring are separated into an upper spring chamber and a lower spring chamber by a transverse partition. The first torsion spring is arranged in the upper spring chamber, and the second torsion spring is arranged in the lower spring chamber. The ends of the first torsion spring and the second torsion spring close to the partition abut against a spring stopper on the base. The upper end of the first torsion spring is sealed in the upper spring chamber by a first sleeve, and the lower end of the second torsion spring is sealed in the lower spring chamber by a second sleeve.

[0008] The first spring adjustment assembly is connected in the first sleeve, and the lower end of the first spring adjustment assembly extends into the upper spring cavity of the base and can contact the upper end portion of the first torque spring; the second spring adjustment assembly is connected in the second sleeve, and the upper end of the second spring adjustment assembly extends into the lower spring cavity of the base and can contact the lower end portion of the second torque spring.

[0009] Furthermore, the tensioning arm assembly includes a first tensioning arm, a second tensioning arm and a tensioning arm screw for connecting the first tensioning arm and the second tensioning arm, wherein the first tensioning arm includes a Z-shaped bracket, the first sleeve is arranged at one end of the Z-shaped bracket, the tensioning wheel assembly mounting portion is arranged at the other end of the Z-shaped bracket, and a downwardly extending connecting portion is provided in the middle portion of the Z-shaped bracket; the second tensioning arm includes an L-shaped bracket, one end of the L-shaped bracket is fixedly connected to the connecting portion by a tensioning arm screw, and the other end of the L-shaped bracket is provided with the second sleeve; the portion from the first sleeve along the Z-shaped bracket, the L-shaped bracket to the second sleeve together constitutes a C-shaped support portion.

[0010] Furthermore, in order to facilitate the installation of the tensioning wheel assembly, the tensioning wheel assembly mounting portion includes a first stepped shaft, and the first stepped shaft is provided with a first internal threaded hole along the axial direction.

[0011] Specifically, the tensioning wheel assembly includes a tensioning wheel, a bearing and a tensioning wheel screw. The tensioning wheel is rotatably connected to the tensioning arm assembly through the bearing, and the bearing is restricted on the first stepped shaft by the tensioning wheel screw threaded in the first internal threaded hole.

[0012] Furthermore, in order to adjust the working state of the first torque spring, the first spring adjustment assembly includes a first pushing bolt, a first pushing piece and a first telescopic spring, the inner wall of the first sleeve is processed with a stepped hole, which are respectively a first hole portion, a second hole portion and a third hole portion from top to bottom, and the hole diameter gradually decreases, wherein the first hole portion is processed with an internal thread, and a first double keyway, that is, two keyways, is axially provided on the side wall of the second hole portion, and a first arc-shaped through hole is provided on the bottom surface of the first sleeve outside the third hole portion, and the first pushing piece includes a first supporting ring and a first arc-shaped pushing block connected as a whole, the first arc-shaped pushing block is arranged below the first supporting ring, and the outer surface of the first supporting ring Two first protrusions are provided on the edge of the first push member that match the first double keyway. During assembly, the first telescopic spring and the first push member are sequentially placed in the first sleeve. The first pushing bolt is inserted into the first sleeve and threadedly connected to the first hole portion to block the first push member. The first arc-shaped push block of the first push member is inserted into the first arc-shaped through hole. At this time, the first telescopic spring is supported between the first support ring of the first push member and the bottom surface of the first sleeve. The upper end of the pivot passes through the third hole portion, the first telescopic spring, and the first support ring in sequence. Adjusting the first pushing bolt can change the length of the first arc-shaped push block inserted into the first arc-shaped through hole, thereby changing the working state of the first torque spring. The insertion end of the first arc-shaped push block is provided with a first curved surface on the side facing the end of the first torque spring. To ensure smooth adjustment, the end of the first torque spring is provided with a first rotating block. The upper end of the first rotating block is provided with a second curved surface that matches the first curved surface. In the non-operating state, the first curved surface and the second curved surface are offset and overlapped, and at least part of the first curved surface and the second curved surface are in a vertically opposed state.

[0013] Furthermore, in order to adjust the working state of the second torque spring, the second spring adjustment assembly includes a second pushing bolt, a second pushing block and a second telescopic spring. The inner wall of the second sleeve is processed with a stepped hole, which are respectively a fourth hole portion, a fifth hole portion and a sixth hole portion from bottom to top, and the hole diameter gradually decreases. The fourth hole portion is processed with an internal thread, and a second double keyway, that is, two keyways, is axially provided on the side wall of the fifth hole portion. A second arc-shaped through hole is provided on the top surface of the second sleeve outside the sixth hole portion. The second push piece includes an integrally connected second support ring and a second arc-shaped push block. The second arc-shaped push block is arranged above the second support ring, and the outer surface of the second support ring The edge of the second pusher is provided with two second protrusions that match the second double keyway. During assembly, the second telescopic spring and the second pusher are sequentially placed in the second sleeve. The second pushing bolt is inserted into the second sleeve and threadedly connected to the fourth hole portion to block the second pusher. The second arc-shaped push block of the second pusher is inserted into the second arc-shaped through hole. At this time, the second telescopic spring is supported between the second support ring of the second pusher and the top surface of the second sleeve. The lower end of the pivot passes through the fourth hole portion, the second telescopic spring, and the second support ring in sequence. Adjusting the second pushing bolt can change the length of the second arc-shaped push block inserted into the second arc-shaped through hole, thereby changing the working state of the second torque spring. The insertion end of the second arc-shaped push block is provided with a third arc surface on the side facing the end of the second torque spring. To ensure smooth adjustment, the end of the second torque spring is provided with a second rotating block. The lower end of the second rotating block is provided with a fourth arc surface that matches the third arc surface. In the non-operating state, the third and fourth arc surfaces are offset and overlapped, and at least part of the third and fourth arc surfaces are in a vertically opposed state.

[0014] Furthermore, it also includes a first damping assembly arranged in the upper spring cavity, the first damping assembly includes a first metal damping ring and a first plastic damping ring, the first metal damping ring and the first plastic damping ring are arranged in the upper spring cavity from the inside to the outside, and the inner wall of the first metal damping ring is in contact with the first torque spring, and the outer wall of the first plastic damping ring is connected to the inner wall of the outer ring.

[0015] Furthermore, it also includes a second damping assembly arranged in the lower spring cavity, the second damping assembly includes a second metal damping ring and a second plastic damping ring, the second metal damping ring and the second plastic damping ring are arranged in the lower spring cavity from the inside to the outside, and the inner wall of the second metal damping ring is in contact with the second torsion spring, and the outer wall of the second plastic damping ring is connected to the inner wall of the outer ring.

[0016] Furthermore, a bushing is further included, which is sleeved on the pivot and located between the inner ring and the pivot. The bushing can avoid direct friction with the inner ring when the pivot rotates, thereby protecting the inner ring of the base.

[0017] Furthermore, long arc-shaped grooves are provided on the inner ring and outer ring at the upper and lower ends of the base. The first rotating block and the second rotating block have the same structure, and cylindrical shafts are provided on the front and rear sides. The cylindrical shafts on both sides are respectively embedded in the arc-shaped grooves of the inner ring and the outer ring, and can slide along the arc-shaped grooves. A spring positioning hole is also provided on the side where the first rotating block and the second rotating block are connected to the spring.

[0018] During assembly of the first tensioning arm, first pusher, first telescopic spring, first pressure bolt, and pivot: The center through-hole of the first tensioning arm is interference-fitted onto the pivot to securely connect the first tensioning arm and the pivot; the first telescopic spring is placed over one end of the pivot; the first arc-shaped pusher block of the first pusher passes through the arc-shaped through-hole of the first tensioning arm, and the two protrusions of the first pusher engage with the double keyway of the first tensioning arm. This double keyway engagement transmits torque between the first pusher and the first tensioning arm. During installation, ensure that the first pusher can freely move axially along the sleeve of the first tensioning arm; screw the first pressure bolt into the internally threaded hole of the first sleeve of the first tensioning arm. At this point, under the upward pressure of the first telescopic spring, the upper portion of the first pusher contacts the lower portion of the first pressure bolt. The assembly process for the second tensioning arm, second pusher, second telescopic spring, second pressure bolt, and pivot is the same as described above and will not be repeated here.

[0019] Working principle:

[0020] In the non-working state, under the action of the first telescopic spring, the first arc-shaped push block at the bottom of the first push member moves away from the first rotating block, and the two do not contact each other; similarly, under the action of the second telescopic spring, the second arc-shaped push block at the top of the second push member moves away from the second rotating block, and the two do not contact each other.

[0021] When a torque spring is needed, rotate its corresponding push bolt to make the push bolt move axially toward the base. At the same time, the bottom surface of the push bolt pushes the push piece to move toward the base. The arc surface of the arc-shaped push block at the bottom of the push piece begins to contact the arc surface of the corresponding rotating block. As the push bolt continues to rotate, the arc surface of the arc-shaped push block squeezes the arc surface of the rotating block. The cylindrical shafts at both ends of the rotating block slide in the arc groove of the base. The rotating block squeezes the end face of the torque spring, and the end face of the torque spring makes a circular motion, providing preload force for the torque spring ( Any torque spring in an automatic tensioner requires a certain amount of preload during installation and before operation. Continue rotating the push bolt until the pusher reaches the limit of axial movement (at this point, the stepped surface on the outer diameter of the push bolt contacts the stepped surface on the inner diameter of the tensioning arm). At this point, the curved surface of the pusher's push block disengages from the curved surface of the rotating block. Instead, the flat surface on the side of the curved push block contacts the flat surface at the bottom of the rotating block. As the tensioning arm rotates, this contact surface transmits the torque of the torque spring to the tensioning arm. When a torque spring is no longer needed, simply rotate the push bolt in the opposite direction, freeing it from the base. Under the force of the expansion spring, the pusher also moves axially away from the base. The rotating block now disengages from the curved push block, preventing the torque spring from transmitting to the rotating block, and thus eliminating the need for that torque spring. This method allows the user to determine whether the tensioner uses a specific torque spring, thereby adjusting the tensioner's output torque.

[0022] The beneficial effects of the present invention are as follows: the present invention provides an automatic tensioner with adjustable output torque, which has a simple and compact structure. By combining and separating multiple torque springs to switch the spring stiffness of the tensioner, the output torque can be freely adjusted, thereby expanding the application range of the tensioner; when one of the torque springs is damaged when working alone, the other torque spring can be used to continue working, thereby extending the service life of the entire tensioner; in addition, the two torque springs can also be made to work alternately to reduce link fatigue, thereby further extending the service life of the tensioner. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below with reference to the accompanying drawings and examples.

[0024] Figure 1 It is a schematic diagram of the three-dimensional structure of the automatic tensioner with adjustable output torque of the present invention.

[0025] Figure 2 It is a schematic diagram of the cross-sectional structure of an automatic tensioner with adjustable output torque.

[0026] Figure 3 It is a schematic diagram of the cross-sectional structure of an automatic tensioner with adjustable output torque.

[0027] Figure 4 It is a schematic diagram of the exploded structure of an automatic tensioner with adjustable output torque.

[0028] Figure 5 It is a schematic diagram of the side structure of an automatic tensioner with adjustable output torque.

[0029] Figure 6 yes Figure 5 Schematic diagram of the cross-sectional structure of GG.

[0030] Figure 7 It is a structural diagram of the base.

[0031] Figure 8 It is a schematic diagram of the cross-sectional structure of the base.

[0032] Figure 9 yes Figure 8 Schematic diagram of the cross-sectional structure of AA.

[0033] Figure 10 It is a schematic diagram of the three-dimensional structure of the first tensioning arm.

[0034] Figure 11 Schematic diagram of the top view of the first tensioning arm.

[0035] Figure 12 yes Figure 11 Schematic diagram of the cross-sectional structure of the BB.

[0036] Figure 13 It is a schematic diagram of the three-dimensional structure of the second tensioning arm.

[0037] Figure 14 Schematic diagram of the top view of the second tensioning arm.

[0038] Figure 15 yes Figure 14 Schematic diagram of the cross-sectional structure of CC.

[0039] Figure 16 It is a structural diagram of the first push member / the second push member.

[0040] Figure 17 It is a structural diagram of the first rotating block / second rotating block.

[0041] In the figure: 1-base, 1.1-inner ring, 1.2-outer ring, 1.3-interlayer, 1.4-upper spring chamber, 1.5-lower spring chamber, 1.6-arc groove, 1.7-spring stopper, 1.8-screw fixing part, 1.9-through hole; 2-first torque spring; 3-first rotating block, 3.1-second arc surface, 3.2-cylindrical shaft, 3.3-spring positioning hole; 4-first tensioning arm, 4.1-first sleeve, 4.11-first Hole portion, 4.12-second hole portion, 4.13-third hole portion, 4.14-first double keyway, 4.15-first arc-shaped through hole, 4.2-Z-shaped bracket, 4.3-first stepped shaft, 4.4-first internally threaded hole, 4.5-connecting portion, 5-first push member, 5.1-first support ring, 5.2-first protrusion, 5.3-first arc-shaped push block, 5.4-first arc surface; 6-first pushing bolt; 7-pivot; 8-bushing; 9-first telescopic spring; 10-first metal damping ring; 11-first plastic damping ring; 12-second torque spring; 13-second tensioning arm, 13.1-second sleeve, 13.11-fourth hole portion, 13.12-fifth hole portion, 13.13-sixth hole portion, 13.14-second double keyway, 13.15-second arc-shaped through hole, 13.2-L-shaped bracket; 14-second push bolt; 15-second push member, 15 .1-Second support ring, 15.2-Second protrusion, 15.3-Second arc-shaped push block, 15.4-Third arc surface; 16-Second rotating block, 16.1-Fourth arc surface, 16.2-Cylindrical shaft, 16.3-Spring positioning hole; 17-Second metal damping ring; 18-Second plastic damping ring; 19-Second telescopic spring; 20-Bearing; 21-Tensioning pulley; 22-Tensioning pulley screw; 23-Elastic retaining ring; 24-Tensioning arm screw. DETAILED DESCRIPTION

[0042] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams that illustrate the basic structure of the present invention only in a schematic manner. Therefore, they only show components relevant to the present invention, and directions and references (e.g., up, down, left, right, etc.) may be used solely to facilitate the description of features in the drawings. The following detailed description is therefore not to be taken in a limiting sense, and the scope of the claimed subject matter is defined solely by the appended claims and their equivalents.

[0043] like Figures 1-6As shown, an automatic tensioner with adjustable output torque of the present invention includes a base 1, a first torque spring 2, a first spring adjustment assembly, a second torque spring 12, a second spring adjustment assembly, a pivot 7, a tensioning arm assembly and a tensioning wheel assembly, wherein the tensioning arm assembly has a tensioning wheel assembly mounting portion and a C-shaped support portion, and the tensioning wheel assembly mounting portion and the C-shaped support portion are respectively arranged at both ends of the tensioning arm assembly, and the tensioning wheel assembly is mounted on the tensioning wheel assembly mounting portion, the upper end of the C-shaped support portion is provided with a first sleeve 4.1, and the lower end is provided with a second sleeve 13.1, the base 1 is connected between the first sleeve 4.1 and the second sleeve 13.1, the pivot 7 is axially rotatably connected in the base 1, and the upper and lower ends extend out of the base 1 and are respectively fixed to the first sleeve 4.1 and the second sleeve 13.1, and the pivot 7 relies on its own positioning boss structure and the elastic retaining ring 23 to achieve axial positioning on the base 1. The pivot 7 is also provided with a bushing 8, which is a plastic part and is located between the inner ring 1.1 and the pivot 7. The bushing 8 is used to prevent wear between the base 1 and the pivot 7 during rotation and provide friction torque for the tensioner.

[0044] like Figure 7-10 As shown, the base 1 is a double-layer coaxial cylindrical structure, including a coaxially arranged inner ring 1.1 and an outer ring 1.2, and the inner ring 1.1 and the outer ring 1.2 are separated into an upper spring cavity 1.4 and a lower spring cavity 1.5 by a transverse partition 1.3. The upper and lower sides of the partition 1.3 are both processed with spring stops 1.7 for fixing the spring ends. The inner ring 1.1 and the outer ring 1.2 at the upper and lower ends of the base 1 are both provided with long arc-shaped grooves 1.6. The outer wall of the base 1 is processed with three screw fixing parts 1.8 for screw fixing, and the screw fixing part 1.8 is provided with a through hole 1.9.

[0045] like Figure 2 As shown, to provide friction torque to the tensioner system, a first damping assembly is installed within the upper spring chamber 1.4, and a second damping assembly is installed within the lower spring chamber 1.5. The first and second damping assemblies have essentially the same structure, both being open circular rings, though their sizes may vary depending on the size of the installed torque spring. Specifically, the first damping assembly comprises a first metal damping ring 10 and a first plastic damping ring 11. These are sequentially installed within the upper spring chamber 1.4 from the inside out, with the inner wall of the first metal damping ring 10 contacting the first torque spring 2, and the outer wall of the first plastic damping ring 11 connected to the inner wall of the outer ring 1.2. The second damping assembly includes a second metal damping ring 17 and a second plastic damping ring 18. The second metal damping ring 17 and the second plastic damping ring 18 are arranged in the lower spring cavity 1.5 from the inside to the outside, and the inner wall of the second metal damping ring 17 contacts the second torsion spring 12, and the outer wall of the second plastic damping ring 18 is connected to the inner wall of the outer ring 1.2.

[0046] like Figure 2 、 Figure 3 and Figure 5 As shown, the first torsion spring 2 is a conventional cylindrical coil spring, disposed within the upper spring cavity 1.4. The inner side of the first torsion spring 2 is sheathed over the inner ring 1.1 of the base 1, and the outer side abuts against the first metal damping ring 10. After installation, the first torsion spring 2 rests on a spring stopper 1.7 in the upper spring cavity 1.4 of the base 1. Its upper end is sealed within the upper spring cavity 1.4 by a first sleeve 4.1. A first rotating block 3 is mounted on the end of the first torsion spring 2, which is restrained by cylindrical shafts 3.2 on either side of the first rotating block 3 within the arcuate grooves 1.6 of the inner ring 1.1 and outer ring 1.2 of the upper spring cavity 1.4. A second torsion spring 12 is disposed within the lower spring cavity 1.5. Its structure is similar to that of the first torsion spring 2, but differs in its diameter, number of effective turns, and pitch diameter, thereby providing two different torsional stiffnesses. The upper end of second torque spring 12 rests against spring stop 1.7 on base 1, while its lower end is sealed within lower spring chamber 1.5 via second sleeve 13.1. A second rotating block 16 is mounted on its end. Cylindrical shafts 16.2 on either side of second rotating block 16 constrain the spring within arcuate grooves 1.6 in inner and outer rings 1.1 and 1.2 of lower spring chamber 1.5. Using torque springs with different torsional stiffnesses at the same torsional angle will result in different tensioner output torques.

[0047] The first spring adjustment assembly is connected to the first sleeve 4.1, and the lower end of the first spring adjustment assembly extends into the upper spring cavity 1.4 of the base 1 and is capable of contacting the upper end portion of the first torque spring 2; the second spring adjustment assembly is connected to the second sleeve 13.1, and the upper end of the second spring adjustment assembly extends into the lower spring cavity 1.5 of the base 1 and is capable of contacting the lower end portion of the second torque spring 12.

[0048] In order to facilitate disassembly, the tensioning arm assembly adopts a split structure, and the tensioning arm assembly includes a first tensioning arm, a second tensioning arm 13, and a tensioning arm screw 24 for connecting the first tensioning arm and the second tensioning arm 13. Figure 10-12As shown, the first tensioning arm includes a Z-shaped bracket 4.2, the first sleeve 4.1 is arranged at one end of the Z-shaped bracket 4.2, and the tensioning wheel assembly mounting portion is arranged at the other end of the Z-shaped bracket 4.2. In order to facilitate the installation of the tensioning wheel assembly, the tensioning wheel assembly mounting portion includes a first stepped shaft 4.3, and the first stepped shaft 4.3 is axially provided with a first internal threaded hole 4.4. The middle part of the Z-shaped bracket 4.2 is provided with a connecting portion 4.5 extending downward, and the connecting portion 4.5 is provided with multiple through holes for connecting the tensioning arm screw 24; the inner wall of the first sleeve 4.1 is processed with stepped holes, which are respectively the first hole portion 4.11, the second hole portion 4.12, and the third hole portion 4.13 from top to bottom, and the hole diameter gradually decreases, wherein the first hole portion 4.11 is processed with an internal thread, and the side wall of the second hole portion 4.12 is axially provided with a first double keyway 4.14, i.e., two keyways, and the bottom surface of the first sleeve 4.1 outside the third hole portion 4.13 is provided with a first arc-shaped through hole 4.15, and the third hole portion 4.13 is an ordinary round hole with a chamfered bottom. Figure 13-15 As shown, the second tensioning arm 13 includes an L-shaped bracket 13.2, one end of the L-shaped bracket 13.2 is fixedly connected to the connecting part 4.5 by a tensioning arm screw 24, and the other end of the L-shaped bracket 13.2 is provided with a second sleeve 13.1; the inner wall of the second sleeve 13.1 is processed with a stepped hole, and its structure is consistent with the structure of the first sleeve 4.1, from bottom to top respectively are the fourth hole portion 13.11, the fifth hole portion 13.12, and the sixth hole portion 13.13, and the hole diameter gradually decreases, wherein the fourth hole portion 13.11 is processed with an internal thread, and the side wall of the fifth hole portion 13.12 is axially provided with a second double keyway 13.14, that is, two keyways, and a second arc-shaped through hole 13.15 is provided on the top surface of the second sleeve 13.1 outside the sixth hole portion 13.13; the part from the first sleeve 4.1 along the Z-shaped bracket 4.2, the L-shaped bracket 13.2 to the second sleeve 13.1 together constitutes a C-shaped support portion.

[0049] The tensioning wheel assembly includes a tensioning wheel 21, a bearing 20 and a tensioning wheel screw 22. The tensioning wheel 21 is rotatably connected to the tensioning arm assembly through the bearing 20, and the bearing 20 is restricted on the first stepped shaft 4.3 by the tensioning wheel screw 22 threadedly connected to the first internal threaded hole 4.4.

[0050] In order to adjust the working state of the first torque spring 2, the first spring adjustment assembly includes a first push bolt 6, a first push piece 5 and a first telescopic spring 9. The upper hexagonal shape of the first push bolt 6 is convenient for manual rotation, and a blind hole is opened in the middle. The outer wall is a stepped shaft that matches the internal stepped hole of the first sleeve 4.1, and the first stepped shaft portion corresponding to the first hole portion 4.11 is processed with threads. The radius of the second stepped shaft portion is smaller than that of the first stepped shaft portion, and is a circular optical axis. Figure 16As shown, the first push piece 5 includes a first supporting ring 5.1 and a first arc-shaped pushing block 5.3 connected in one piece. The first arc-shaped pushing block 5.3 is arranged below the first supporting ring 5.1, and two first protrusions 5.2 matching the first double key groove 4.14 are provided on the outer edge of the first supporting ring 5.1. The first protrusion 5.2 is a rectangular structure. With reference to the structure of an ordinary flat key, the first supporting ring 5.1 is a circular plate structure with a circular through hole in the center to facilitate the extension of the pivot 7; the cross-section of the first arc-shaped pushing block 5.3 is an arc-shaped, and the bottom edge is processed with an arc surface for guidance; when assembled, the first telescopic spring 9 and the first push piece 5 are placed in the first sleeve 4.1 in sequence. Inside, the first pushing bolt 6 is inserted into the first sleeve 4.1 and is threadedly connected to the first hole portion 4.11 to block the first pushing member 5, and the first arc-shaped pushing block 5.3 of the first pushing member 5 is inserted from the first arc-shaped through hole 4.15; at this time, the first telescopic spring 9 is supported under pressure between the first support ring 5.1 of the first pushing member 5 and the bottom surface of the first sleeve 4.1, and the upper end of the pivot 7 passes through the third hole portion 4.13, the first telescopic spring 9 and the first support ring 5.1 in sequence. Adjusting the first pushing bolt 6 can change the length of the first arc-shaped pushing block 5.3 inserted into the first arc-shaped through hole 4.15, thereby changing the working state of the first torque spring 2. A first curved surface 5.4 is provided on the side of the insertion end of the first curved push block 5.3 facing the end of the first torque spring 2. In order to ensure smoothness during adjustment, a first rotating block 3 is provided at the end of the first torque spring 2. A second curved surface 3.1 matching the first curved surface 5.4 is provided at the upper end of the first rotating block 3. In the non-working state, the first curved surface 5.4 and the second curved surface 3.1 are offset and overlapped up and down, and at least parts of the first curved surface 5.4 and the second curved surface 3.1 are in a vertically relative state.

[0051] In order to adjust the working state of the second torque spring 12, the second spring adjustment assembly includes a second pushing bolt 14, a second pushing block and a second telescopic spring 19. The structure of the second pushing bolt 14 is basically the same as that of the first pushing bolt 6 and will not be repeated here. The structure of the second push piece 15 is similar to that of the first push piece 5, including an integrally connected second support ring 15.1 and a second arc-shaped push block 15.3. The second arc-shaped push block 15.3 is arranged above the second support ring 15.1, and the outer edge of the second support ring 15.1 is provided with two second protrusions 15.2 that match the second double key groove 13.14; when assembled, the second telescopic spring 19 and the second push piece 15 are placed in the second sleeve 13.1 in sequence, the second pushing bolt 14 is inserted into the second sleeve 13.1 and is threadedly connected to the fourth hole portion 13.11, and the second push piece 15 is screwed to the second sleeve 13.1. The second push piece 15 is blocked, and the second arc-shaped push block 15.3 of the second push piece 15 is inserted into the second arc-shaped through hole 13.15; at this time, the second telescopic spring 19 is supported under pressure between the second support ring 15.1 of the second push piece 15 and the top surface of the second sleeve 13.1, and the lower end of the pivot 7 passes through the fourth hole portion 13.11, the second telescopic spring 19 and the second support ring 15.1 in sequence. Adjusting the second pushing bolt 14 can change the length of the second arc-shaped push block 15.3 inserted into the second arc-shaped through hole 13.15, thereby changing the working state of the second torque spring 12. A third arc surface 15.4 is provided on the side of the insertion end of the second arc-shaped push block 15.3 facing the end of the second torsion spring 12. In order to ensure smoothness during adjustment, a second rotating block 16 is provided at the end of the second torsion spring 12. The lower end of the second rotating block 16 is provided with a fourth arc surface 16.1 matching the third arc surface 15.4. In the non-working state, the third arc surface 15.4 and the fourth arc surface 16.1 are offset and overlapped at the top and bottom, and at least part of the third arc surface 15.4 and the fourth arc surface 16.1 are in a relative state up and down.

[0052] In this embodiment, the first rotating block 3 and the second rotating block 16 have basically the same structure. Figure 17 As shown, cylindrical shafts 3.2 and 16.2 are provided on the front and rear sides, and the cylindrical shafts 3.2 and 16.2 on both sides are respectively embedded in the arc grooves 1.6 of the inner ring 1.1 and the outer ring 1.2, and can slide along the arc grooves 1.6. The side where the first rotating block 3 and the second rotating block 16 are connected to the spring is also provided with a spring positioning hole 3.3 and a spring positioning hole 16.3.

[0053] Working principle:

[0054] In the non-working state, under the action of the first telescopic spring 9, the first arc-shaped push block 5.3 at the bottom of the first push member 5 is away from the first rotating block 3, and the two do not contact each other; similarly, under the action of the second telescopic spring 19, the second arc-shaped push block 15.3 at the top of the second push member 15 is away from the second rotating block 16, and the two do not contact each other.

[0055] When the first torque spring 2 is used, the first pushing bolt 6 is rotated to make the first pushing bolt 6 move axially toward the base 1. At the same time, the bottom surface of the first pushing bolt 6 pushes the first pushing member 5 to move toward the base 1. The arc surface of the first arc-shaped pushing block 5.3 at the bottom end of the first pushing member 5 begins to contact the arc surface of the first rotating block 3. As the first pushing bolt 6 continues to rotate, the arc surface of the first arc-shaped pushing block 5.3 squeezes the arc surface of the first rotating block 3. The cylindrical shafts 3.2 at both ends of the first rotating block 3 slide in the arc groove 1.6 of the base 1. The first rotating block 3 squeezes the end surface of the first torque spring 2. The end face of the torque spring 2 performs a circular motion, providing a preload force for the first torque spring 2. The first push bolt 6 continues to rotate until the first push member 5 reaches the limit of axial motion (at this position, the stepped surface of the push bolt's outer diameter contacts the stepped surface of the tensioning arm's inner diameter). At this point, the curved surface of the first arcuate push block 5.3 of the first push member 5 disengages from the curved surface of the first rotating block 3. Instead, the flat surface of the side of the first arcuate push block 5.3 contacts the flat surface at the lower end of the first rotating block 3. When the tensioning arm assembly rotates, the torque of the first torque spring 2 is transmitted to the tensioning arm via this contact surface. When the first torque spring 2 is no longer needed, the first push bolt 6 is simply rotated in the opposite direction to disengage it from the base 1. Under the elastic force of the first telescopic spring 9, the first push member 5 also moves axially away from the base 1. At this point, the first rotating block 3 disengages from the first arcuate push block 5.3 of the first push member 5, preventing the first torque spring 2 from transmitting torque to the first rotating block 3, thereby eliminating the need for the first torque spring 2.

[0056] When the second torsion spring 12 is used, its working principle is the same as that of the first torsion spring 2. Since the installation relationship is mirror-symmetrical with the first torsion spring 2, the operation and movement directions of the relevant components are opposite to those of the relevant components of the first torsion spring 2. Therefore, they will not be repeated.

[0057] In this embodiment, the first torsion spring 2 and the second torsion spring 12 have different spring stiffnesses. Assuming that the spring stiffness of the first torsion spring 2 is K1 and the spring stiffness of the second torsion spring 12 is K2, when the first tensioning arm and the second tensioning arm 13 rotate θ degrees around the pivot 7 during operation, three output torques are obtained by selecting different torque spring combinations, as follows:

[0058] (1) If only the first torque spring 2 is used, the output torque of the tensioner is M = M1 ± M f =K1θ±M f , where M1=K1θ provides the spring torque for the first torque spring 2, M f The friction torque provided by the bushing 8, the first metal damping, the first plastic damping, the second metal damping, and the second plastic damping in this process.

[0059] (2) If only the second torque spring 12 is used, the output torque of the tensioner is M = M2 ± M f =K2θ±M f , where M2=K2θ provides spring torque for the second torque spring 12;

[0060] (3) When the first torque spring 2 and the second torque spring 12 are called at the same time, the output torque of the tensioner is M=M1+M2±M f =(K1+K2)θ±M f .

[0061] That is, by selecting a different torque spring, the spring stiffness of the tensioner can be changed, thereby changing the spring torque of the tensioner and further changing the total output torque of the tensioner.

[0062] With the above-described preferred embodiments of the present invention as inspiration, and with reference to the above description, relevant personnel may make various changes and modifications without departing from the scope of the present invention. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. An automatic tensioner with adjustable output torque, characterized by: It includes a base, a first torque spring, a first spring adjustment assembly, a second torque spring, a second spring adjustment assembly, a pivot, a tensioning arm assembly and a tensioning wheel assembly, wherein: The tensioning arm assembly comprises a tensioning wheel assembly mounting portion and a C-shaped support portion, and the tensioning wheel assembly mounting portion and the C-shaped support portion are respectively arranged at both ends of the tensioning arm assembly, the tensioning wheel assembly is mounted on the tensioning wheel assembly mounting portion, the upper end of the C-shaped support portion is provided with a first sleeve, and the lower end is provided with a second sleeve, the base is connected between the first sleeve and the second sleeve, the pivot is axially rotatably connected in the base, and the upper and lower ends extend out of the base and are respectively fixedly connected to the first sleeve and the second sleeve; The base is a double-layer coaxial cylindrical structure, including a coaxially arranged inner ring and outer ring, and the inner ring and the outer ring are separated into an upper spring chamber and a lower spring chamber by a transverse partition. The first torsion spring is arranged in the upper spring chamber, and the second torsion spring is arranged in the lower spring chamber. The ends of the first torsion spring and the second torsion spring close to the partition abut against a spring stopper on the base. The upper end of the first torsion spring is sealed in the upper spring chamber by a first sleeve, and the lower end of the second torsion spring is sealed in the lower spring chamber by a second sleeve. The first spring adjustment assembly is connected to the first sleeve, and the lower end of the first spring adjustment assembly extends into the upper spring cavity of the base and is capable of contacting the upper end of the first torsion spring; the second spring adjustment assembly is connected to the second sleeve, and the upper end of the second spring adjustment assembly extends into the lower spring cavity of the base and is capable of contacting the lower end of the second torsion spring; The tensioning arm assembly includes a first tensioning arm, a second tensioning arm and a tensioning arm screw for connecting the first tensioning arm and the second tensioning arm, wherein the first tensioning arm includes a Z-shaped bracket, the first sleeve is arranged at one end of the Z-shaped bracket, the tensioning wheel assembly mounting portion is arranged at the other end of the Z-shaped bracket, and a downwardly extending connecting portion is provided in the middle portion of the Z-shaped bracket; the second tensioning arm includes an L-shaped bracket, one end of the L-shaped bracket is fixedly connected to the connecting portion by a tensioning arm screw, and the other end of the L-shaped bracket is provided with the second sleeve; the portion from the first sleeve along the Z-shaped bracket, the L-shaped bracket to the second sleeve together constitutes a C-shaped support portion.

2. The automatic tensioner with adjustable output torque according to claim 1, characterized in that: The mounting portion of the tensioning wheel assembly includes a first stepped shaft, and the first stepped shaft is provided with a first internal threaded hole along the axial direction.

3. The automatic tensioner with adjustable output torque according to claim 2, characterized in that: The tensioning wheel assembly includes a tensioning wheel, a bearing and a tensioning wheel screw. The tensioning wheel is rotatably connected to the tensioning arm assembly through the bearing, and the bearing is restricted on the first stepped shaft by the tensioning wheel screw threaded in the first internal threaded hole.

4. The automatic tensioner with adjustable output torque according to claim 1, characterized in that: The first spring adjustment assembly includes a first pushing bolt, a first pushing member and a first telescopic spring, the inner wall of the first sleeve is processed with a stepped hole, which includes a first hole portion, a second hole portion and a third hole portion from top to bottom, and the hole diameter gradually decreases, wherein the first hole portion is processed with an internal thread, a first double key groove is axially provided on the side wall of the second hole portion, a first arc-shaped through hole is provided on the bottom surface of the first sleeve outside the third hole portion, the first pushing member includes a first supporting ring and a first arc-shaped pushing block connected as a whole, the first arc-shaped pushing block is arranged below the first supporting ring, and two first protrusions matching the first double key groove are provided on the outer edge of the first supporting ring; The first telescopic spring and the first pushing member are sequentially placed in the first sleeve, the first pushing bolt is inserted into the first sleeve and threadedly connected to the first hole portion to block the first pushing member, and the first arc-shaped pushing block of the first pushing member is inserted into the first arc-shaped through hole; A first arc surface is provided on the side of the insertion end of the first arc-shaped push block facing the end of the first torque spring, a first rotating block is provided at the end of the first torque spring, and a second arc surface matching the first arc surface is provided at the upper end of the first rotating block. In the non-working state, the first arc surface and the second arc surface are offset and overlapped up and down, and at least parts of the first arc surface and the second arc surface are in a vertically relative state.

5. The automatic tensioner with adjustable output torque according to claim 1, characterized in that: The second spring adjustment assembly includes a second pushing bolt, a second pushing member and a second telescopic spring. The inner wall of the second sleeve is processed with a stepped hole, which includes a fourth hole portion, a fifth hole portion and a sixth hole portion from bottom to top, and the hole diameter gradually decreases. The fourth hole portion is processed with an internal thread, and a second double key groove is axially provided on the side wall of the fifth hole portion. A second arc-shaped through hole is provided on the top surface of the second sleeve outside the sixth hole portion. The second pushing member includes an integrally connected second support ring and a second arc-shaped pushing block. The second arc-shaped pushing block is arranged above the second support ring, and two second protrusions matching the second double key groove are provided on the outer edge of the second support ring; The second telescopic spring and the second pushing member are sequentially placed in the second sleeve, the second pushing bolt is inserted into the second sleeve and threadedly connected to the fourth hole portion to block the second pushing member, and the second arc-shaped pushing block of the second pushing member is inserted into the second arc-shaped through hole; A third arc surface is provided on the side of the insertion end of the second arc-shaped push block facing the end of the second torque spring, a second rotating block is provided at the end of the second torque spring, and a fourth arc surface is provided at the lower end of the second rotating block to match the third arc surface. In the non-working state, the third arc surface and the fourth arc surface are offset and overlapped up and down, and at least part of the third arc surface and the fourth arc surface are in a vertically relative state.

6. The automatic tensioner with adjustable output torque according to claim 1, characterized in that: It also includes a first damping assembly arranged in the upper spring cavity, the first damping assembly including a first metal damping ring and a first plastic damping ring, the first metal damping ring and the first plastic damping ring are arranged in the upper spring cavity from the inside to the outside, and the inner wall of the first metal damping ring is in contact with the first torque spring, and the outer wall of the first plastic damping ring is connected to the inner wall of the outer ring.

7. The automatic tensioner with adjustable output torque according to claim 1, characterized in that: It also includes a second damping assembly arranged in the lower spring cavity, the second damping assembly includes a second metal damping ring and a second plastic damping ring, the second metal damping ring and the second plastic damping ring are arranged in the lower spring cavity from the inside to the outside, and the inner wall of the second metal damping ring is in contact with the second torsion spring, and the outer wall of the second plastic damping ring is connected to the inner wall of the outer ring.

8. The automatic tensioner with adjustable output torque according to claim 1, characterized in that: The utility model further comprises a bushing which is sleeved on the pivot and located between the inner ring and the pivot.

9. The automatic tensioner with adjustable output torque according to claim 1, characterized in that: The inner ring and outer ring at the upper and lower ends of the base are provided with long arc-shaped grooves. The first rotating block and the second rotating block have the same structure. Cylindrical shafts are provided on the front and back sides. The cylindrical shafts on both sides are respectively embedded in the arc-shaped grooves of the inner ring and the outer ring and can slide along the arc-shaped grooves. A spring positioning hole is also provided on the side where the first rotating block and the second rotating block are connected to the spring.

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