A chain tensioning device

Abstract

A chain tensioning device belongs to the field of chain transmission technology, comprising a base, a mounting groove provided on one side of the upper surface of the base, a driving mechanism provided in the mounting groove, a locking mechanism for limiting the rotation angle of the driving mechanism, and a guide rail hinged to the top of the base via a connecting rod assembly. The driving mechanism is used in conjunction with the guide rail, and the top of the guide rail is an arc-shaped surface. The shape and size of the arc-shaped surface satisfy the following requirements: the loose side of the tensioned chain can be offset as a whole toward the tight side in the form of an arc curve, and the chain tension formed by the offset can ensure smooth engagement between the chain and the sprocket while compensating for the chain elongation. The present invention changes the traditional chain system's method of rotational tensioning around a fulcrum, realizes overall translational tensioning of the guide rail, avoids the risk of sudden changes in the running trajectory, and improves the operational stability of the chain system.

Description

Technical Field

[0001] The invention belongs to the technical field of chain transmission, and particularly relates to a chain tensioning device. Background Art

[0002] The chain's trajectory is constantly changing during operation. This is due to the impact vibrations caused by the chain's polygonal effect, load changes, and speed fluctuations. Furthermore, the chain experiences wear and elongation during service, particularly on the loose side of the chain. Excessive fluctuations in the chain's trajectory or insufficient chain tension can lead to risks such as abnormal chain vibration and tooth skipping. Therefore, maintaining a taut chain is a prerequisite for ensuring normal and stable operation.

[0003] Tensioners are generally divided into hydraulic tensioners and mechanical tensioners. Traditional chain systems rely on the tensioner to push the guide rail around the fulcrum, causing it to concave inward toward the chain system, changing the chain's trajectory and achieving tension. When the chain experiences significant elongation or fluctuation due to wear, this chain tensioning method can cause the initial trajectory to concave significantly on one side of the tensioner. This can cause a sudden change in the chain's trajectory, resulting in uneven engagement between the chain and sprocket, leading to abnormal operation of the entire chain system. Furthermore, when the distance between the tight and loose sides of the chain is small, the tensioning stroke of rotary tensioning is more limited, failing to fully compensate for the chain's elongation and impacting the chain's service life. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, the present invention discloses a chain tensioning device that transforms the traditional tensioner's guide rail's rotational tensioning method around a fulcrum into an overall inward translational tensioning method. This optimizes the chain system's trajectory and enhances overall system stability. Furthermore, a ratchet mechanism is employed to lock the tensioning device, reducing fluctuations in the chain system's reciprocating tension and extending its service life.

[0005] To achieve the above object, the technical solution of the present invention is:

[0006] A chain tensioning device includes a base, a mounting groove provided on one side of the upper surface of the base, a driving mechanism arranged in the mounting groove, a locking mechanism for limiting the rotation angle of the driving mechanism, and a guide rail hinged to the top end of the base through a connecting rod assembly. The driving mechanism and the guide rail are used in conjunction with each other, and the top end of the guide rail is an arc-shaped surface. The shape and size of the arc-shaped surface meet the requirements of: being able to cause the loose side of the tensioned chain to be offset as a whole toward the tight side in the form of an arc curve, and the chain tension formed by the offset can ensure smooth engagement between the chain and the sprocket while compensating for the chain elongation.

[0007] Preferably, the length of the arcuate surface is at least 1 / 2 of the length of the loose side of the chain.

[0008] Preferably, the guide rail is connected to the base through two sets of connecting rod assemblies, and the two sets of connecting rod assemblies each include two connecting rods symmetrically arranged at the front and rear ends of the guide rail. The top and bottom ends of the two symmetrical connecting rods are respectively hinged to the guide rail or the base through a common hinge shaft, and the two sets of connecting rod assemblies are always parallel to each other during rotation. The outer surface of the base where the right side of the connecting rod is located is also provided with a limiting boss for limiting the maximum rotation angle of the connecting rod.

[0009] Preferably, the driving mechanism includes a cam, one end of the cam is provided with a slot for placing a torsion spring, the bottom of the slot is coaxially provided with an axial hole that passes through the end face of the other side of the cam, one torsion arm of the torsion spring is confined in a torsion arm slot extending outward from the outer wall of the slot, and the other torsion arm extends outward and abuts against the bottom of the mounting slot. Under the elastic force of the torsion spring, the arc-shaped upper surface of the cam away from the axial hole can lift the guide rail to the maximum displacement.

[0010] Preferably, the lower surface of the guide rail facing the driving mechanism is provided with an inclined groove for use with the cam.

[0011] Preferably, the locking mechanism includes a ratchet, a pawl, a pawl shaft and a pawl spring, the wheel hole of the ratchet is coaxial with the shaft hole, a positioning hole is provided on the cam located on the outer side of the shaft hole, and the ratchet is also provided with a pin hole, the ratchet is fixedly connected to the cam by a pin passing through the pin hole and inserted into the positioning hole, and the cam and ratchet are rotatably connected to the front and rear groove walls of the mounting groove by an axis passing through the shaft hole and the wheel hole; the pawl is rotatably connected to the groove wall of the mounting groove by a pawl shaft arranged on the side away from the ratchet wheel, and one end of the pawl facing the ratchet wheel is meshed with the ratchet teeth on the outer periphery of the ratchet wheel, and a pawl spring is provided at the lower part of the end of the pawl away from the ratchet wheel, the bottom end of the pawl spring is fixedly connected to the bottom of the mounting groove, and the lower end of the pawl contacts the top end of the pawl spring. When the pawl spring is in the natural state, the pawl is locked with the ratchet teeth, and one end of the pawl shaft passes through the outside of the base and constitutes a handle for controlling the pawl.

[0012] Preferably, the width of the inclined groove is 1-3 mm larger than the thickness of the cam, the thickness of the guide rail is larger than the outer width of the outer section of the chain, and a weight-reducing groove is provided.

[0013] Preferably, when the guide rail moves to its maximum stroke, the angle formed by the plane where the axis of the hinge shaft and the axis of the shaft hole on the lower side of each group of connecting rod assemblies are located and the connecting rod assembly is less than 60°.

[0014] Preferably, the guide rail is made of PA6, PA46 or PA66, the ratchet teeth are trapezoidal teeth or triangular teeth, the pawl is straight-headed, and the ratchet and pawl are made of 45# or 40#Cr.

[0015] Preferably, a mounting hole is provided on the base.

[0016] The beneficial effects of a chain tensioning device of the present invention are as follows: the present invention changes the traditional chain system's tensioning method of rotating around a fulcrum, realizes the overall translational tensioning of the guide rail, avoids the risk of sudden changes in the running trajectory, and improves the running stability of the chain system; the cam profile is used to control the stroke of the guide plate, so that the tensioning amplitude of the chain system at a certain moment can be reasonably optimized and designed, and the chain fluctuation under specific working conditions of the chain can be more effectively reduced; the locking mechanism realizes the locking function of the tensioning device, and prevents the tensioning device from repeatedly extending and retracting when the chain tension is abnormal; the present invention has a compact structure, and under the same trajectory tensioning requirement, the required layout space is smaller. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 , a schematic structural diagram of the present invention;

[0018] Figure 2 , a schematic structural diagram of the driving mechanism of the present invention;

[0019] Figure 3 , a schematic structural diagram of the guide rail of the present invention;

[0020] Figure 4 , a schematic structural diagram of the locking mechanism of the present invention;

[0021] Figure 5 , the guide rail of the present invention is located at the chain running track corresponding to the initial position;

[0022] Figure 6 , the guide rail of the present invention is located at the chain running track corresponding to the working position;

[0023] 1: Base, 1-1: Mounting slot, 1-2: Limiting boss, 2: Driving mechanism, 2-1: Cam, 2-2: Torsion spring, 2-2-1: Torsion arm, 3: Guide rail, 3-1: Bevel slot, 3-2: Weight reduction slot, 4: Locking mechanism, 4-1: Ratchet, 4-1-1: Pin hole, 4-1-2: Ratchet, 4-2: Pawl, 4-3: Pawl shaft, 4-4: Pawl spring, 5: Step bolt, 6: Connecting rod. DETAILED DESCRIPTION

[0024] The following description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0025] In one embodiment, the present invention provides a chain tensioning device, such as Figure 1-4As shown, it includes a base 1, a mounting groove 1-1 opened on one side of the upper surface of the base 1, a driving mechanism 2 arranged in the mounting groove, a locking mechanism 4 for limiting the rotation angle of the driving mechanism 2, and a guide rail 3 hinged to the top of the base through a connecting rod assembly. The driving mechanism 2 is used in conjunction with the guide rail 3. The top of the guide rail 3 is an arc-shaped surface. The shape and size of the arc-shaped surface meet the requirements of: being able to make the loose side of the tensioned chain offset toward the tight side in the form of an arc curve, and the chain tension formed by the offset can ensure smooth engagement between the chain and the sprocket while compensating for the chain elongation.

[0026] In a further embodiment, Figure 5 、 6 As shown, the length of the arcuate surface is at least 1 / 2 of the length of the loose side of the chain.

[0027] In a further embodiment, Figure 1-4 As shown, the guide rail 3 is connected to the base 1 through two groups of connecting rod assemblies, and the two groups of connecting rod assemblies include two connecting rods 6 symmetrically arranged at the front and rear ends of the guide rail. The top and bottom ends of the two symmetrical connecting rods 6 are respectively hinged to the guide rail 3 or the base 1 through a common hinge axis, and the two groups of connecting rod assemblies 6 are always parallel to each other during the rotation process. The outer surface of the base 1 where the right side of the connecting rod 6 is located is also provided with a limiting boss 1-2 for limiting the maximum rotation angle of the connecting rod 6.

[0028] In a further embodiment, Figure 1-4 As shown, the drive mechanism 2 includes a cam 2-1. A slot is provided at one end of the cam 2-1, housing a torsion spring 2-2. A coaxial axial hole extends through the other end of the cam, coaxially disposed at the bottom of the slot. One torsion arm of the torsion spring 2-2 is confined within an outwardly extending torsion arm slot on the outer wall of the slot, while the other torsion arm extends outward and abuts against the bottom of the mounting slot. Under the elastic force of the torsion spring, the curved upper surface of the cam, facing away from the axial hole, is capable of lifting the guide rail 3 to its maximum displacement. In this embodiment, the profile of the cam 2-1 is set based on the desired tensioning stroke of the chain system.

[0029] In a further embodiment, Figure 1 、 3 As shown, the lower surface of the guide rail 3 facing the driving mechanism 2 is provided with an inclined groove 3-1 for use with a cam.

[0030] In a further embodiment, Figure 1 、 4As shown, the locking mechanism 4 includes a ratchet 4-1, a pawl 4-2, a pawl shaft 4-3 and a pawl spring 4-4. The wheel hole of the ratchet 4-1 is coaxial with the shaft hole, and a positioning hole is provided on the cam located outside the shaft hole. The ratchet 4-1 is also provided with a pin hole 4-1-1. The ratchet is fixedly connected to the cam by a pin passing through the pin hole 4-1-1 and inserted into the positioning hole. The cam and the ratchet are rotatably connected to the front and rear groove walls of the mounting groove through an axis passing through the shaft hole and the wheel hole; the pawl 4-2 is connected by a pin located away from the ratchet. A pawl shaft 4-3 on the side is rotatably connected to the wall of the mounting slot. The end of the pawl 4-2 facing the ratchet wheel meshes with the ratchet teeth 4-1-2 on the outer periphery of the ratchet wheel 4-1. A pawl spring 4-4 is provided below the end of the pawl 4-2 facing away from the ratchet wheel. The bottom end of the pawl spring 4-4 is fixedly connected to the bottom of the mounting slot. The bottom end of the pawl 4-2 contacts the top end of the pawl spring 4-4. When the pawl spring is in its natural state, the pawl and the ratchet teeth are locked. One end of the pawl shaft 4-3 extends through the outside of the base and forms a handle for operating the pawl. In this embodiment, the base is fixed to a device equipped with a chain system through the mounting hole. The pawl and the ratchet teeth are disengaged by rotating the handle. After the guide rail is brought into contact with the loose edge of the chain and compressed to an appropriate tension, the handle can be released to mesh the ratchet teeth with the pawl, thereby locking the rotation angle of the cam. The elastic force of the pawl spring is sufficient to overcome the elastic force of the torsion spring, thereby enabling the pawl to limit the position of the cam.

[0031] In a further embodiment, Figure 1 、 4 As shown, the width of the inclined groove 3-1 is 1-3 mm larger than the thickness of the cam, the thickness of the guide rail 3 is larger than the outer width of the outer section of the chain, and a weight-reducing groove 3-2 is provided.

[0032] In a further embodiment, Figure 6 As shown, when the guide rail 3 moves to the maximum stroke, the angle between the plane where the axis of the hinge shaft on the lower side of each group of connecting rod assemblies 6 and the axis of the shaft hole are located and the connecting rod assembly 6 is less than 60°, thereby being able to control the arc limit after the loose side of the chain is tensioned, so that the gear and chain can engage smoothly.

[0033] In a further embodiment, Figure 1 、 4 As shown, the guide rail 3 is made of PA6, PA46 or PA66, the ratchet teeth 4-1-2 are trapezoidal teeth or triangular teeth, the pawl 4-2 is straight-headed, and the ratchet wheel 4-1 and the pawl 4-2 are made of 45# or 40#Cr.

[0034] In a further embodiment, Figure 1 、 5 As shown in 6, the base is provided with mounting holes to facilitate the fixation of the equipment installed with the chain system.

Claims

1. A chain tensioning device, characterized in that it comprises a base, a mounting groove provided on one side of an upper surface of the base, a driving mechanism provided in the mounting groove, a locking mechanism for limiting the rotation angle of the driving mechanism, and a guide rail hinged to the top end of the base through a connecting rod assembly, wherein the driving mechanism and the guide rail are used in conjunction with each other, the top end of the guide rail being an arc-shaped surface, the shape and size of the arc-shaped surface being satisfied with: being able to make the loose side of the tensioned chain deviate as a whole toward the tight side in the form of an arc curve, and the chain tensioning amount formed by the deviation can ensure smooth engagement of the chain with the sprocket while compensating for the chain elongation; the driving mechanism comprises a cam, one end of the cam is provided with a slot for placing a torsion spring, the bottom of the slot is coaxially provided with an axial hole passing through the end face of the other side of the cam, one torsion arm of the torsion spring is limited in a torsion arm slot extending outwardly from the outer wall of the slot, and the other torsion arm extends outwardly and abuts against the bottom of the mounting groove, under the elastic force of the torsion spring, the cam moves away from the arc on one side of the shaft hole The shaped upper surface can lift the guide rail to the maximum displacement; the contour curve of the cam is set according to the required tensioning stroke of the chain system; the locking mechanism includes a ratchet, a pawl, a pawl shaft and a pawl spring, the wheel hole of the ratchet is coaxial with the shaft hole, and a positioning hole is provided on the cam located outside the shaft hole. The ratchet is also provided with a pin hole, and the ratchet is fixedly connected to the cam by a pin passing through the pin hole and inserted into the positioning hole. The cam and the ratchet are rotatably connected to the front and rear groove walls of the mounting groove through an axis passing through the shaft hole and the wheel hole; the pawl is rotatably connected to the groove wall of the mounting groove through a pawl shaft provided on the side away from the ratchet, and the end of the pawl facing the ratchet is engaged with the ratchet teeth on the outer periphery of the ratchet. A pawl spring is provided at the lower part of the end of the pawl away from the ratchet, and the bottom end of the pawl spring is fixedly connected to the bottom of the mounting groove, and the lower end of the pawl contacts the top of the pawl spring. When the pawl spring is in the natural state, the pawl is locked with the ratchet teeth. One end of the pawl shaft passes through the outside of the base and constitutes a handle for controlling the pawl.

2. A chain tensioner according to claim 1, characterized in that: The length of the arcuate surface is at least 1 / 2 of the length of the loose side of the chain.

3. A chain tensioner according to claim 2, characterized in that: The guide rail is connected to the base through two sets of connecting rod assemblies. The two sets of connecting rod assemblies include two connecting rods symmetrically arranged at the front and rear ends of the guide rail. The top and bottom ends of the two symmetrical connecting rods are respectively hinged to the guide rail or the base through a common hinge shaft, and the two sets of connecting rod assemblies are always parallel to each other during rotation. The outer surface of the base where the right side of the connecting rod is located is also provided with a limiting boss for limiting the maximum rotation angle of the connecting rod.

4. A chain tensioner according to claim 3, characterized in that: The lower surface of the guide rail facing the driving mechanism is provided with an inclined groove used in conjunction with the cam.

5. A chain tensioning device according to claim 4, characterized in that: The width of the inclined groove is 1-3 mm larger than the thickness of the cam, the thickness of the guide rail is larger than the outer width of the outer section of the chain, and a weight-reducing groove is provided.

6. A chain tensioner according to claim 5, characterized in that: When the guide rail moves to its maximum stroke, the angle formed by the plane where the axis of the hinge shaft and the axis of the shaft hole on the lower side of each group of connecting rod assemblies are located and the connecting rod assembly is less than 60°.

7. A chain tensioner according to claim 6, characterized in that: The guide rail is made of PA6, PA46 or PA66, the ratchet teeth are trapezoidal teeth or triangular teeth, the pawl is straight-headed, and the ratchet wheel and pawl are made of 45# or 40#Cr.

8. A chain tensioner according to claim 7, characterized in that: The base is provided with a mounting hole.

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