Industrial robot small space synchronous wheel tensioning device

Abstract

The application relates to a small-space synchronous wheel tensioning device of an industrial robot, which comprises a base, a fastening pipe, an adjusting bolt, a pressing plate, a spring, two connecting rods, two sliding blocks and two top blocks. The tensioning device has a small structure width, can apply a load in the vertical direction, tension the synchronous wheel in the horizontal direction, and is suitable for a small-space structure of a small industrial robot, in which the two ends of the synchronous wheel are not provided with the installation positions of the tensioning wheels due to the small center distance of the synchronous belt, and the tensioning wheels cannot be installed on the side edges.

Description

Technical Field

[0001] This invention relates to the field of industrial robot technology, and specifically to a small-space synchronous wheel tensioning device for industrial robots. Background Technology

[0002] Industrial robots often use synchronous pulleys as transmission components. However, due to the complexity of robot transmission, after prolonged operation, synchronous pulleys may experience poor meshing. Therefore, synchronous pulley belts need to be readjusted after a period of use. Common tensioning devices for synchronous pulley transmission systems include periodic tensioning devices, automatic tensioning devices, and tensioning pulleys. Regardless of the method used, additional accessories are required. However, due to the limited space and inconvenient installation of robots, especially small industrial robots, common tensioning devices occupy a large space and are difficult to assemble and adjust. Therefore, there is an urgent need for a compact synchronous pulley tensioning device for industrial robots. Summary of the Invention

[0003] The purpose of this invention is to provide a tensioning device for synchronous pulleys in small spaces for industrial robots, which solves the problem that tensioning pulleys cannot be installed on the sides of small industrial robots due to the small center distance of the synchronous belt and the lack of mounting positions at both ends of the synchronous pulleys.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A tensioning device for a small space synchronous wheel of an industrial robot includes a base, a fixing tube, an adjusting bolt, a pressure plate, a spring, two connecting rods, two sliders and two top blocks;

[0006] The setter tube is mounted on the base. The setter tube has elongated holes on both sides that communicate with the inside of the setter tube. The pressure plate passes through the setter tube, and both ends of the pressure plate extend out of the setter tube from the two elongated holes. The spring is set inside the setter tube, and the upper end of the spring abuts against the pressure plate. The adjusting bolt is rotatably screwed into the setter tube, and the lower end of the adjusting bolt presses against the upper end of the pressure plate.

[0007] The base is also provided with two sliding grooves, which are located on both sides of the fixing tube respectively; two connecting rods are respectively engaged with the two ends of the pressure plate, one end of the connecting rod is hinged to the pressure plate, and the other end is engaged in the sliding groove; two sliders are respectively set in the two sliding grooves, the sliders are engaged with the connecting rods, and the sliders slide in the sliding grooves under the action of the connecting rods;

[0008] Two top blocks are respectively set on the side of the two slides away from the fixing tube. One end of the top block is hinged to the base, and the other end cooperates with the slider. Under the action of the slider, the top block swings with the hinged end as the fulcrum.

[0009] The two side walls of the slide are provided with openings, and the end of the connecting rod is provided with a pin, with both ends of the pin passing through the opening.

[0010] The lower end of the set tube is fixed to the base by a fixing bolt.

[0011] The connecting rod is connected to the pressure plate by rivets.

[0012] The top block is mounted on the base by screws.

[0013] After adopting the above solution, the tensioning device of the present invention has a small structural width, which can achieve the application of load in the vertical direction and tension the synchronous wheel in the horizontal direction. It is suitable for small space structures in small industrial robots where the center distance of the synchronous belt is small and there are no installation positions for the synchronous wheel at both ends, and the tensioning wheel cannot be installed on the side. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the tensioning device structure of the present invention;

[0015] Figure 2 This is a top view of the tensioning device of the present invention;

[0016] Figure 3 This is a simplified diagram of the forces acting on the slider of the present invention;

[0017] Figure 4 This is a simplified diagram of the slider motion of the present invention;

[0018] Figure 5 This is a schematic diagram of the top block parameters;

[0019] Figure 6 This is a schematic diagram of a four-axis structure for a small robot.

[0020] Figure 7 for Figure 6 Top view;

[0021] Figure 8 for Figure 6 A sectional view.

[0022] Label Explanation:

[0023] 1. Adjusting bolt; 2. Set tube; 3. Rivet; 4. Fixing bolt; 5. Top block; 6. Base; 61. Slide groove; 62. Opening; 7. Slider; 8. Spring; 9. Connecting rod; 10. Pressure plate; 11. Hole pin; 12. Body; 13. Driven wheel; 14. Tensioning device; 15. Motor flange; 16. Servo motor; 17. Locking bolt; 18. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0025] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0026] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0027] Reference Figure 1-2 As shown, the present invention discloses a small space synchronous wheel tensioning device for industrial robots, which includes a base 6, a fixing tube 2, an adjusting bolt 1, a pressure plate 11, a spring 8, two connecting rods 10, two sliders 7 and two top blocks 5.

[0028] The aforementioned setter tube 2 is mounted on the base 6, and elongated holes communicating with the interior of the setter tube 2 are provided on both sides of the setter tube 2. A pressure plate 11 passes through the setter tube 2, with both ends of the pressure plate 11 extending out of the setter tube 2 from the two elongated holes. A spring 8 is disposed inside the setter tube 2, with its upper end abutting against the pressure plate 11. An adjusting bolt 1 is rotatably screwed into the setter tube 2, with its lower end pressing against the upper end of the pressure plate 11. The base 6 also has two sliding grooves 61, located on both sides of the setter tube 2. Two connecting rods 10 are respectively fitted at both ends of the pressure plate 11, with one end of the connecting rod 10 hinged to the pressure plate 11 and the other end fitted into the sliding groove 61. Two sliders 7 are respectively disposed in the two sliding grooves 61, with the sliders 7 cooperating with the connecting rods 10, and sliding within the sliding grooves 61 under the action of the connecting rods 10. Two top blocks 5 are respectively set on the side of the two sliding grooves 61 away from the fixing tube 2. One end of the top block 5 is hinged to the base 6, and the other end cooperates with the slider 7. Under the action of the slider 7, the top block 5 swings with the hinge end as the fulcrum.

[0029] When adjusting bolt 1 is tightened, adjusting bolt 1 moves downward, causing pressure plate 11 to be subjected to downward pressure, thereby overcoming the elastic force of spring 8 and moving downward along the set tube 2. This pushes connecting rod 10 and top block 5 to move slider 7 to both sides. After being subjected to force, top block 5 rotates outward around plug screw 9 by an angle, pushing motor flange 16 outward, thereby tensioning the synchronous belt.

[0030] In order to ensure that the end of the connecting rod 10 can be stably located in the slide groove 61, the slide groove 61 of the present invention is provided with openings 62 on both sides, and the end of the connecting rod 10 is provided with a pin 12, the two ends of which are inserted into the openings 62.

[0031] In this embodiment, the lower end of the setter tube 2 is fixed to the base 6 by a fixing bolt 4. The connecting rod 10 is connected to the pressure plate 11 by a rivet 3. The top block 5 is mounted on the base 6 by a plug screw 9.

[0032] The above-mentioned stress analysis method for the tensioning device requires determining the structural parameters of the tensioning device. In the tensioning device, the length of connecting rod 10, the length of the groove in slider 7, the distance between the center of slider 7 and the axis at the right limit position of the groove in slider 7, and the length of top block 5 are fixed values. For example... Figure 3-5 As shown, the specific force analysis method is as follows:

[0033] 1) Determine the parameters of link 10; assume the length of link 10 is AB = L1.

[0034] 2) Determine the parameters of the slider 7 groove; to ensure that the pin 12 and slider 7 rotate and slide smoothly in the groove 61, the width of the groove 61 is equal to the radius of the pin 12, the top block 5, the diameter and the side length of the slider 7, and is set as a; the distance between the center of the slider 7 and the axis of the right limit position of the groove is set as b, and the length of the groove is set as c; the distance from the rotation center of the top of the connecting rod 10 to the right center of the groove 61 is d; assume that the horizontal displacement of the slider 7 is s.

[0035] 3) Determine the parameters of top block 5; set the length of top block 5 as L3; define the distance L2 from the rotation center of top block 5 to the right center of the slide 61.

[0036] 4) Determine the force conditions of the tensioning device; assuming that the adjusting bolt 1 applies a force of magnitude F1 to the pressure plate 11, then the forces on the slider and the top block 5 are as follows: Figure 3 and Figure 4 As shown, Figure 3 and Figure 4 In the diagram, AB is the center of rotation of the link, and CD is the position of the center of rotation after the link has been displaced a certain distance. AB and CD are actually both centers of rotation of the link, but they represent the positions at different angles.

[0037] The force acting on the slider is:

[0038] σ1=arc sin((d+s) / L1)

[0039] β1=90°-α1

[0040] F3 = 0.5F1·COSα1·COSβ1

[0041] The forces acting on top block 5 are:

[0042] α3=arc sin(2a / (L2-bs))

[0043] β3=90-α3

[0044] F5 = F3·COSa3·COSβ3

[0045] 5) Determine the ejection distance of top block 5;

[0046] Assume that when the top block 5 rotates out, the minimum angle of ∠GFE is β3, and the angle after the slider displacement s is β4; Figure 5 In the diagram, points F and G are the rotation center of the top block and the center of the slider, respectively. E is the intersection of the slider center, the top block, the slider center, and the center line of the top block. During the contact operation between the slider and the top block, the line connecting their intersection and the slider center is always perpendicular to the center line EF of the top block, with an angle GEF = 90°.

[0047] The ejection distance of top block 5 is:

[0048] β3=arc sin(2a / (L2-b))

[0049] β4=arc sin(2a / (L2-bs))

[0050] h = L3·(sinβ4-sinβ3)

[0051] To illustrate the content of this invention in detail, the following example demonstrates the application of the tensioning device 15 in a general-purpose small robot four-axis structure, verifying the structural parameters of the tensioning device 15 and its tensioning effect on the synchronous belt. This four-axis structure has a small body space; there are no mounting positions for the synchronous pulleys at either end, and tensioning pulleys cannot be installed on the sides. The tensioning device 15, however, has a minimum width of only 10mm, allowing for installation and use in a small space. The robot four-axis structure includes a body 13, a driven pulley 14, the aforementioned tensioning device 15, a motor flange 16, a servo motor 17, and locking bolts 18. The servo motor 17 is mounted inside the body 13 via the motor flange 16. The output shaft of the servo motor 17 is connected to the drive pulley, which is connected to the driven pulley 14 via a belt or chain. The tensioning device 15 is located beside the servo motor 17, and its top block 5 abuts against the motor flange 16.

[0052] Determine the parameters of tensioning device 15:

[0053] 1) Determine the parameters of connecting rod 10; take the length of connecting rod 10 as AB = L1 = 15mm;

[0054] 2) Determine the parameters of the slider groove; the width of the groove 61 is equal to that of the flat-head pin 12 with holes, the radius of the top block 5, the diameter of the top block 5 slider 7, and the side length, a = 3mm; the distance between the center of the slider and the axis of the right limit position of the slider groove is b = 3.5mm, and the length of the slider groove is c = 10mm; the distance from the rotation center of the top of the connecting rod 10 to the right center of the groove 61 is d = 7mm; assume that the horizontal displacement of the slider is s = 4mm;

[0055] 3) Determine the parameters of top block 5; the length of top block 5 L3 = 10mm; the distance from the rotation center of top block 5 to the center of the right side of slide groove 61 L2 = 15mm;

[0056] 4) Determine the stress condition of the tensioning device 15;

[0057] Assuming that adjusting bolt 1 applies a force of F1 = 60N to pressure plate 11, the forces acting on slider and top block 5 are shown in the figure.

[0058] The force acting on the slider is:

[0059] α1=arc sin((7+4) / 15)=47.17°

[0060] β1 = 90° - 47.17° = 42.83°

[0061] F3=0.5·60·COS47.17°·COS42.83°=14.96N

[0062] The forces acting on top block 5 are:

[0063] α3=arc cos(2·3 / (15-3.5-4))=36.87°

[0064] β3 = 90° - 53.13° = 53.13°

[0065] F5=14.96·COS53.13°·COS36.87°=7.18N

[0066] 5) Determine the ejection distance of top block 5; assume that the minimum angle of ∠GFE when top block 5 rotates out is β3 and the maximum angle is β4;

[0067] The ejection distance of top block 5 is:

[0068] β4=arc sin(2·3 / (15-3.5-4))=53.13°

[0069] β3=aFc sin(2·3 / (15-3.5))=31.45°

[0070] h=10·(sin53.13°-sin31.45°)=2.78mm

[0071] Verification was conducted when the slider displacement distances were 1mm, 2mm, and 3mm, and the force on the top block 5 and the ejection distance of the top block 5 were measured:

[0072] The displacement distances of the slider were verified to be 1mm, 2mm, and 3mm, and the force and ejection distance of the top block 5 were as follows:

[0073]

[0074] The synchronous belt used in this structure has the following specifications: 3M-width 06-59 teeth, belt length 177, and effective belt tension of 13N. As can be seen from the above calculation, applying a force of F1 = 60N to the pressure plate 11 by adjusting bolt 1 can ensure that the pushing distance of top block 5 can apply sufficient tension to the synchronous belt within the range of 0.50-2.78mm.

[0075] The specific operating method of this device is as follows:

[0076] Install the tensioning device 15 into the position shown on the main body 13, and fix it with the locking bolt 18 (but do not tighten it). Tighten the adjusting bolt 1, and the top block 5 pushes the motor flange 16 to increase the center distance between the driven wheel 14 and the servo motor 17, thereby tensioning the synchronous belt connecting the driven wheel 14 and the servo motor 17. Tighten the locking bolt 18, and use a tension meter to measure whether the belt tension is within the theoretical effective tension.

[0077] In summary, the tensioning device of the present invention has a small structural width, which enables the application of load in the vertical direction and tensioning of the synchronous pulley in the horizontal direction. It is suitable for small industrial robots with small space structures where the center distance of the synchronous belt is small and there are no mounting positions for the synchronous pulleys at both ends, and the tensioning pulley cannot be installed on the side.

[0078] In the description of the embodiments of this application, it should be understood that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product of this application is usually placed in when in use, or the orientation or positional relationship that is commonly understood by those skilled in the art. It is only for the convenience of describing this application and simplifying the description, and is not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this application.

[0079] Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0080] In the description of the embodiments of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for mutual communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0081] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms should not be construed as necessarily referring to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

Claims

1. A tensioning device for synchronous wheels in a small space for industrial robots, characterized in that: It includes a base, a setter tube, an adjusting bolt, a pressure plate, a spring, two connecting rods, two sliders, and two top blocks; The setter tube is mounted on the base. The setter tube has elongated holes on both sides that communicate with the inside of the setter tube. The pressure plate passes through the setter tube, and both ends of the pressure plate extend out of the setter tube from the two elongated holes. The spring is set inside the setter tube, and the upper end of the spring abuts against the pressure plate. The adjusting bolt is rotatably screwed into the setter tube, and the lower end of the adjusting bolt presses against the upper end of the pressure plate. The base is also provided with two sliding grooves, which are located on both sides of the fixing tube respectively; two connecting rods are respectively engaged with the two ends of the pressure plate, one end of the connecting rod is hinged to the pressure plate, and the other end is engaged in the sliding groove; two sliders are respectively set in the two sliding grooves, the sliders are engaged with the connecting rods, and the sliders slide in the sliding grooves under the action of the connecting rods; Two top blocks are respectively set on the side of the two slides away from the fixing tube. One end of the top block is hinged to the base, and the other end is engaged with the slider. Under the action of the slider, the top block swings with the hinged end as the fulcrum. The slide has openings on both sides, and the end of the connecting rod is provided with a pin, with both ends of the pin inserted into the opening; the lower end of the set tube is fixed to the base by a fixing bolt; the connecting rod is connected to the pressure plate by a rivet; the top block is installed on the base by a plug screw.

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