A wheel pressure testing fixture

Abstract

This utility model discloses a wheel pressure testing fixture, relating to the field of tire testing technology. It includes a frame, a three-dimensional force sensor, a fixed base plate, a roller, a tire, an axle, and a pre-tightening assembly. The frame is a rectangular frame structure, with its bottom fixedly connected to the upper surface of the three-dimensional force sensor via the pre-tightening assembly. The lower surface of the three-dimensional force sensor is bolted to the fixed base plate. The roller is horizontally mounted between two upright plates on either side of the frame via the axle, and its outer circumferential surface rolls in contact with the outer circumferential surface of the tire. The pre-tightening assembly includes bolts, spring washers, and double nuts. The spring washers are fitted onto the bolt shanks and clamped between the bottom of the frame and the nuts. The double nuts are tightened sequentially along the bolt axial direction to lock the relative position of the frame and the three-dimensional force sensor. This utility model aims to solve the problem in the prior art of lacking dynamic wheel pressure testing fixtures applicable to different wheel diameters and rotational speeds, which cannot accurately simulate the actual pressure of the wheel on the ground and monitor wheel slippage and uneven loading during rotation.

Description

Technical Field

[0001] This utility model relates to the field of tire testing technology, specifically to a tire pressure testing fixture. Background Technology

[0002] With the rapid development of artificial intelligence, the AGV (Automated Guided Vehicle) industry, as an indispensable part of AI, has achieved significant progress. However, in the practical application of AGVs, various dynamic working conditions are encountered. To better control the movement state of AGVs, it is necessary to test the wheel pressure. Currently, there is a lack of dynamic wheel pressure testing fixtures applicable to different wheel diameters and rotational speeds, which cannot accurately simulate the real pressure of the wheels on the ground or monitor wheel slippage and uneven loading during rotation. Therefore, a new type of wheel pressure testing fixture is urgently needed to solve these problems. Utility Model Content

[0003] Technical problem to be solved by the utility model

[0004] The present invention aims to solve the problem that the existing technology lacks dynamic wheel pressure testing fixtures applicable to different wheel diameters and rotation speeds, which cannot accurately simulate the real pressure of the wheel on the ground and monitor wheel slippage and off-center loading under rotation.

[0005] Technical solution

[0006] To solve the above problems, the technical solution provided by this utility model is as follows:

[0007] A wheel pressure testing fixture includes a frame, a three-dimensional force sensor, a fixed base plate, a roller, a tire, a shaft, and a pre-tightening assembly. The frame is a rectangular frame structure, with its bottom fixedly connected to the upper end face of the three-dimensional force sensor via the pre-tightening assembly, and the lower end face of the three-dimensional force sensor bolted to the fixed base plate. The roller is horizontally mounted between the two upright plates of the frame via the shaft, and the outer circumferential surface of the roller makes rolling contact with the outer circumferential surface of the tire. The pre-tightening assembly includes a bolt, a spring washer, and two nuts. The spring washer is sleeved on the bolt shank and clamped between the bottom of the frame and the nuts. The two nuts are tightened sequentially along the bolt axial direction to lock the relative position of the frame and the three-dimensional force sensor.

[0008] The wheel pressure testing fixture, through the cooperation of a frame, a three-dimensional force sensor, a fixed base plate, rollers, and polyurethane tires, enables wheel pressure testing of polyurethane wheels under dynamic working conditions. The three-dimensional force sensor detects force values ​​related to wheel pressure, and the rolling contact between the rollers and the polyurethane tires simulates the actual interaction between the wheel and the ground. The overall structure is adaptable to different testing needs, providing a basis for monitoring phenomena such as slippage and uneven loading during wheel rotation, thereby assisting in controlling the motion status of AGVs and other equipment.

[0009] Optionally, at least three sets of mounting holes are symmetrically provided on the two side uprights of the frame along the height direction. Each set of mounting holes includes two coaxially arranged through holes, with the two ends of the shaft passing through the corresponding through holes on the two side uprights respectively. The hole spacing between two adjacent sets of mounting holes is 50-150mm, and the hole spacing can be adjusted in steps according to the difference in tire diameter.

[0010] By setting at least three sets of symmetrical mounting holes along the height direction on the upright plates on both sides of the frame, and the hole spacing between adjacent sets of mounting holes is 50-150mm and can be adjusted in steps according to the difference in the diameter of the polyurethane tire, it can adapt to polyurethane tires of different diameters, ensuring that tires of different sizes maintain a suitable contact state with the roller, thereby accurately simulating the real pressure of different diameter wheels on the ground and meeting diverse dynamic wheel pressure testing needs.

[0011] Optionally, a copper sleeve is embedded in the inner wall of the mounting hole. The inner diameter of the copper sleeve is in clearance fit with the outer diameter of the shaft, with a clearance of 0.02-0.05mm. Both ends of the copper sleeve protrude 1-2mm from the surface of the frame upright plate.

[0012] By embedding a copper sleeve in the inner wall of the mounting hole, and utilizing the precise clearance of 0.02-0.05mm between the copper sleeve and the shaft, it is possible to ensure that the shaft can rotate freely in the mounting hole to simulate real rolling conditions, while also limiting the radial wobble of the shaft and avoiding test errors caused by excessive clearance between the mounting hole and the shaft. At the same time, the two ends of the copper sleeve protrude 1-2mm from the surface of the frame upright plate, which can reduce the direct friction between the shaft and the frame upright plate, reduce the wear rate, extend the service life of the tooling, and ensure the stability of long-term testing.

[0013] Optionally, the three-dimensional force sensor is a ring structure with its central through hole coaxially arranged with the bolt hole at the bottom of the frame, and a copper foil gasket with a thickness of 0.1-0.2 mm is provided between the sensing surface of the three-dimensional force sensor and the contact surface at the bottom of the frame to eliminate the influence of assembly gap on force value monitoring.

[0014] By designing the three-dimensional force sensor as a ring structure and setting copper foil gaskets, the assembly gap between the frame and the sensor can be eliminated, ensuring that the wheel pressure force is fully transmitted to the sensor sensing surface and avoiding force value monitoring distortion caused by gaps; the coaxial design of the central through hole and the bolt hole ensures that the bolt connection will not interfere with the force value sensing accuracy of the sensor.

[0015] Optionally, the outer circumferential surface of the roller is covered with a rubber layer with a thickness of 5-10 mm, the rubber layer has a Shore hardness of 60-70 HA, and the surface of the rubber layer is provided with circumferentially distributed anti-slip textures with a texture depth of 0.5-1 mm.

[0016] By setting a rubber layer with specific parameters and anti-slip texture on the outer circumference of the roller, the friction characteristics of different ground surfaces can be simulated, making the contact state between the tire and the roller closer to the real working conditions. The hardness and thickness design of the rubber layer can buffer the impact force during the test process, reduce the damage to the tire and sensor caused by rigid contact, and at the same time, the anti-slip texture can prevent the tire from slipping, ensuring the authenticity of the test data.

[0017] Optionally, the fixed base plate is made of steel plate, with four evenly distributed leveling bolts at its bottom. The lower end of the leveling bolts is provided with rubber pads, and the fixed base plate has a waist-shaped mounting groove for fixing to the ground.

[0018] The leveling bolts and waist-shaped mounting grooves on the fixed base plate enable the overall leveling of the fixture to be adjusted, ensuring the accuracy of the test benchmark. They also adapt to the fixing hole positions on different ground surfaces, enhancing the flexibility and stability of the fixture installation. The rubber pads can absorb vibrations during the test and reduce the impact of external interference on the sensor.

[0019] Optionally, the top of the frame is provided with a level mounting base, in which a bubble level is embedded for monitoring the levelness of the frame. The level has an accuracy of 0.1 mm / m.

[0020] By installing a high-precision bubble level on the top of the frame, the horizontal status of the frame can be monitored in real time. This facilitates timely detection and correction of the frame's tilt during installation and testing, avoids deviation in the force direction of the force sensor due to frame tilt, and ensures the accuracy of wheel pressure test data.

[0021] Optionally, the signal output terminal of the three-dimensional force sensor is connected to the data acquisition module via a shielded cable. The shielded cable is covered with a metal corrugated tube, and both ends of the corrugated tube are sealed to the sensor housing and the data acquisition module housing, respectively.

[0022] By combining shielded cables and metal corrugated tubes, the design can reduce the impact of external electromagnetic interference on sensor signals and ensure the stability of data transmission. The corrugated tubes also provide mechanical protection for the cables, preventing damage caused by pulling and abrasion during the testing process. Meanwhile, the sealed connection can prevent dust and water damage and adapt to complex testing environments.

[0023] Beneficial effects

[0024] Compared with the prior art, the technical solution provided by this utility model has the following advantages:

[0025] The stepped adjustment design of the mounting holes can precisely adapt to polyurethane wheels of various sizes, solving the problem of poor compatibility of traditional tooling.

[0026] The copper foil gasket and shielded cable design between the three-dimensional force sensor and the frame improves the force value monitoring accuracy to ±0.5%FS, ensuring the accuracy of slippage and off-center load data;

[0027] Details such as double nuts and spring washers for pre-tightening ensured that the tooling remained stable and showed no loosening or significant wear after 1000 hours of continuous testing, significantly improving its stability. Attached Figure Description

[0028] Figure 1 A schematic diagram of the structure of a wheel pressure testing fixture proposed in an embodiment of this utility model;

[0029] Figure 2 A side view of a wheel pressure testing fixture proposed in an embodiment of this utility model;

[0030] Figure 3 A cross-sectional view of a wheel pressure testing fixture proposed for an embodiment of this utility model;

[0031] Figure 4 A partial cross-sectional view of a wheel pressure testing fixture proposed for an embodiment of this utility model;

[0032] 1. Roller; 2. Three-dimensional force sensor; 3. Fixed base plate; 4. Frame; 5. Polyurethane tire; 6. Spring pad; 7. Double nut; 8. Shaft; 9. Large wheel mounting hole; 10. Middle wheel mounting hole; 11. Small wheel mounting hole; 12. Bolt. Detailed Implementation

[0033] To further understand the content of this utility model, a detailed description of this utility model will be provided in conjunction with the accompanying drawings and embodiments.

[0034] Example 1

[0035] Combined with appendix Figure 1-4 A wheel pressure testing fixture includes a frame 4, a three-dimensional force sensor 2, a fixed base plate 3, a roller 1, a tire, a shaft 8, and a pre-tightening assembly. The frame 4 is a rectangular frame structure, and its bottom is fixedly connected to the upper end face of the three-dimensional force sensor 2 through the pre-tightening assembly. The lower end face of the three-dimensional force sensor 2 is connected to the fixed base plate 3 by bolts 12. The roller 1 is horizontally mounted between the two upright plates of the frame 4 through the shaft 8, and the outer peripheral surface of the roller 1 is in rolling contact with the outer peripheral surface of the tire. The pre-tightening assembly includes bolts 12, spring washers 6, and double nuts 7. The spring washers 6 are sleeved on the shank of the bolts 12 and clamped between the bottom of the frame 4 and the nuts. The double nuts 7 are tightened sequentially along the bolts 12 to lock the relative position of the frame 4 and the three-dimensional force sensor 2.

[0036] Frame 4 serves as the main support for the overall structure; the three-dimensional force sensor 2 is located between the bottom of frame 4 and the fixed base plate 3, playing a core role in force value monitoring; the fixed base plate 3 is at the bottom, providing a stable installation foundation for the entire tooling; the roller 1 is horizontally mounted between the two side uprights of frame 4 via shaft 8, located in the middle area of ​​frame 4; the polyurethane tire 5 rolls in contact with the outer circumference of roller 1, located on the outer side of roller 1; the bolt 12 in the pre-tightening assembly passes through the bottom of frame 4, the three-dimensional force sensor 2 and the fixed base plate 3, the spring washer 6 is sandwiched between the bottom of frame 4 and the nut, and the double nuts 7 are arranged sequentially along the bolt 12 to achieve locking.

[0037] Installation process: First, place the three-dimensional force sensor 2 on the fixed base plate 3 and initially connect the fixed base plate 3 and the three-dimensional force sensor 2 with bolts 12; next, align the bottom of the frame 4 with the upper end face of the three-dimensional force sensor 2, pass the bolts 12 through the bottom of the frame 4 and the spring washer 6, and then connect them to the three-dimensional force sensor 2 and the fixed base plate 3. First install the spring washer 6, and then tighten the double nuts 7 in sequence to complete the fixation of the frame 4, the three-dimensional force sensor 2 and the fixed base plate 3; finally, pass the shaft 8 through the two side uprights of the frame 4, install the roller 1 on the shaft 8, and ensure that the roller 1 rolls in contact with the outer circumference of the polyurethane tire 5 to complete the installation of the overall tooling.

[0038] Combined with appendix Figure 2 At least three sets of mounting holes are symmetrically provided along the height direction on the two side uprights of the frame 4, including large wheel mounting hole 9, medium wheel mounting hole 10 and small wheel mounting hole 11. The three sets of mounting holes are arranged in a figure-eight pattern to accommodate rollers 1 of different diameters. Each set of mounting holes includes two coaxial through holes, and the two ends of the shaft 8 are respectively inserted into the corresponding through holes on the two side uprights. The hole spacing between two adjacent sets of mounting holes is 50-150mm, and the hole spacing can be adjusted in steps according to the difference in tire diameter.

[0039] The uprights on both sides of frame 4 serve as the load-bearing structure for mounting holes. The uprights are perpendicular to the bottom of frame 4 and symmetrically distributed on both sides of frame 4. The mounting holes are through holes that penetrate the uprights. Two mounting holes in each group are coaxially arranged in the horizontal direction, and the corresponding mounting holes on both sides of the uprights maintain the same axis. At least three groups of mounting holes are evenly distributed along the height direction of the uprights, forming a combination of holes arranged vertically. The hole spacing is set to a stepped interval of 50-150mm according to the wheel diameter adjustment requirements.

[0040] Installation process: During installation, select a set of mounting holes with matching heights on both sides of the frame 4 according to the wheel diameter of the polyurethane tire 5 to be tested; pass both ends of the shaft 8 through the corresponding through holes on both sides of the upright plate to ensure that the horizontal error of the shaft 8 does not exceed 0.02mm / m; if the wheel diameter is changed, the shaft 8 needs to be disassembled and a new set of mounting holes with the corresponding height needs to be selected. By adjusting the position of the mounting holes of the shaft 8 at different heights, the contact state between the roller 1 and the polyurethane tire 5 can be adapted, and the wheel diameter adaptation adjustment can be completed.

[0041] The inner wall of the mounting hole is fitted with a copper sleeve. The inner diameter of the copper sleeve is in clearance fit with the outer diameter of the shaft 8. The clearance is 0.02-0.05mm, and both ends of the copper sleeve protrude 1-2mm from the surface of the upright plate of the frame 4.

[0042] The copper sleeve is embedded in the inner wall of the mounting holes on both sides of the frame 4, and is interference-fitted with the mounting holes to ensure reliable fixation; the axis of the copper sleeve coincides with the axis of the mounting hole, and its inner diameter is slightly larger than the outer diameter of the shaft 8 to form a precision clearance fit; the length of the copper sleeve is consistent with the depth of the mounting hole, and both ends protrude 1-2mm to the inner and outer sides of the vertical plate, respectively, and the protruding part covers the contact area between the shaft 8 and the vertical plate.

[0043] Installation process: Before installation, the mounting holes of the frame 4 upright plate are precisely cleaned to remove burrs and impurities; the copper sleeve is embedded into the mounting hole by cold pressing or heating the frame 4 to ensure that the copper sleeve fits tightly with the inner wall of the mounting hole without loosening; after embedding, check the protrusion of both ends of the copper sleeve to ensure that both sides protrude 1-2mm from the surface of the upright plate; finally, the shaft 8 is inserted into the copper sleeve of one upright plate, passes through the roller 1, and exits from the copper sleeve of the other upright plate to complete the installation of the shaft 8 with the mounting hole.

[0044] The three-dimensional force sensor 2 has a ring-shaped structure, with its central through hole coaxially aligned with the bolt hole at the bottom of the frame 4. A 0.1-0.2mm thick copper foil gasket is placed between the sensing surface of the three-dimensional force sensor 2 and the contact surface at the bottom of the frame 4 to eliminate the influence of assembly gaps on force value monitoring. The three-dimensional force sensor 2 is externally protected by a cuboid shell for protection and fixation.

[0045] The three-dimensional force sensor 2 is ring-shaped and horizontally positioned between the bottom of the frame 4 and the fixed base plate 3. Its central through hole is coaxially aligned with the bolt holes at the bottom of the frame 4 and the bolt holes at the fixed base plate 3. A copper foil gasket is sandwiched between the sensing surface (upper end surface) of the sensor and the contact surface at the bottom of the frame 4, with a thickness of 0.1-0.2mm, covering the effective sensing area of ​​the sensor.

[0046] Installation process: First, place the three-dimensional force sensor 2 on the fixed base plate 3, aligning the sensor bolt holes with the holes of the fixed base plate 3; after evenly applying Vaseline to the sensor sensing surface, lay the copper foil gasket, ensuring that the gasket is completely in contact with the sensing surface; align the bottom of the frame 4 with the sensor, insert the bolts 12, and complete the fixation according to the pre-tightening component requirements, filling the assembly gap through the plastic deformation of the copper foil.

[0047] The outer circumferential surface of roller 1 is covered with a rubber layer with a thickness of 5-10mm. The Shore hardness of the rubber layer is 60-70HA, and the surface of the rubber layer is provided with circumferentially distributed anti-slip textures with a texture depth of 0.5-1mm.

[0048] The rubber layer tightly wraps around the outer circumference of the roller 1, with a uniform thickness of 5-10 mm and a Shore hardness of 60-70 HA. The circumferentially distributed anti-slip patterns are opened on the surface of the rubber layer, with a pattern depth of 0.5-1 mm, arranged in an evenly spaced ring, covering the entire area of ​​the roller 1 in contact with the tire.

[0049] Installation process: After the roller 1 is processed, the rubber layer is bonded and fixed to the outer circumference of the roller 1 by vulcanization process to ensure no bubbles and peeling; anti-slip texture is formed on the surface of the rubber layer by laser engraving or mold pressing, and the depth and uniformity of the texture are checked; finally, the roller 1 is installed on the shaft 8 by bearing to ensure that the coaxiality error of the outer circle of the rubber layer does not exceed 0.1mm.

[0050] Combined with appendix Figure 3 , 4 The fixed base plate 3 is made of steel plate, and there are 4 evenly distributed leveling bolts 12 at the bottom. The lower end of the leveling bolts 12 is provided with rubber pads, and the fixed base plate 3 is provided with a waist-shaped mounting groove for fixing to the ground.

[0051] The fixed base plate 3 is made of steel plate and is horizontally set at the bottom of the fixture; four leveling bolts 12 are evenly distributed at the four corners of the fixed base plate 3 and are vertically screwed into the threaded holes of the base plate, with rubber pads attached to the lower end face; waist-shaped mounting grooves are opened on the edge of the base plate, with no less than four in number, and are evenly distributed along the circumference of the base plate.

[0052] Installation process: Place the fixed base plate 3 on the installation ground and adjust the leveling bolts 12 at the four corners to make the base plate roughly level; use a level to monitor and finely adjust the leveling bolts 12 until the levelness error of the base plate is ≤0.1mm / m; use expansion bolts 12 to fix the base plate to the ground through the waist-shaped mounting groove, and the rubber pads are in close contact with the ground to achieve vibration reduction.

[0053] The top of frame 4 is equipped with a level mounting base, which contains a bubble level for monitoring the levelness of frame 4. The level has an accuracy of 0.1 mm / m.

[0054] The level mounting base is fixed at the center of the top crossbeam of frame 4 and is in the shape of a groove; the bubble level is embedded in the mounting base, and its measuring surface is parallel to the horizontal reference plane of frame 4 with an accuracy of 0.1mm / m. It can simultaneously monitor the levelness of frame 4 in two vertical directions.

[0055] Installation process: After the frame 4 is welded, process the level mounting base on the top crossbeam to ensure that the flatness error of the bottom surface of the mounting base is ≤0.02mm; embed the bubble level into the mounting base and fix it by adhesive or pressing, so that the scale face of the level is facing upward; after installation, adjust the frame 4 by adjusting the leveling bolts 12 to make the bubble of the level in the center position.

[0056] The signal output terminal of the three-dimensional force sensor 2 is connected to the data acquisition module through a shielded cable. The shielded cable is covered with a metal corrugated tube, and the two ends of the corrugated tube are respectively sealed to the sensor housing and the data acquisition module housing.

[0057] One end of the shielded cable is connected to the signal output terminal of the three-dimensional force sensor 2, and the other end is connected to the data acquisition module. A metal corrugated tube is sleeved on the outside of the shielded cable, and both ends are sealed to the sensor housing and the data acquisition module housing through connectors to form a fully enclosed protective structure.

[0058] Installation process: First, connect one end of the shielded cable to the signal output end of the three-dimensional force sensor 2 and lock it in place, and connect the other end to the input end of the data acquisition module; put the metal corrugated tube over the cable and adjust the length of the corrugated tube so that both ends are aligned with the housing interfaces of the sensor and the acquisition module respectively; use threaded connectors to seal the two ends of the corrugated tube to the housing, ensuring that there is no looseness or gaps at the joints.

[0059] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A wheel pressure testing fixture, characterized in that, The system includes a frame, a three-dimensional force sensor, a fixed base plate, a roller, a tire, a shaft, and a pre-tightening assembly. The frame is a rectangular frame structure, with its bottom fixedly connected to the upper surface of the three-dimensional force sensor via the pre-tightening assembly. The lower surface of the three-dimensional force sensor is bolted to the fixed base plate. The roller is horizontally mounted between the two upright plates of the frame via the shaft, and the outer circumference of the roller makes rolling contact with the outer circumference of the tire. The pre-tightening assembly includes bolts, spring washers, and double nuts. The spring washers are fitted onto the bolt shanks and clamped between the bottom of the frame and the nuts. The double nuts are tightened sequentially along the bolt axis to lock the relative position of the frame and the three-dimensional force sensor.

2. The wheel pressure testing fixture according to claim 1, characterized in that, At least three sets of mounting holes are symmetrically provided on the two side uprights of the frame along the height direction. Each set of mounting holes includes two coaxial through holes, with the two ends of the shaft passing through the corresponding through holes on the two side uprights respectively. The hole spacing between two adjacent sets of mounting holes is 50-150mm, and the hole spacing can be adjusted in steps according to the difference in tire diameter.

3. The wheel pressure testing fixture according to claim 2, characterized in that, The inner wall of the mounting hole is fitted with a copper sleeve. The inner diameter of the copper sleeve is in clearance fit with the outer diameter of the shaft. The clearance is 0.02-0.05mm, and both ends of the copper sleeve protrude 1-2mm from the surface of the frame upright plate.

4. The wheel pressure testing fixture according to claim 1, characterized in that, The three-dimensional force sensor has a ring structure with its central through hole coaxially arranged with the bolt hole at the bottom of the frame. A copper foil gasket with a thickness of 0.1-0.2 mm is provided between the sensing surface of the three-dimensional force sensor and the contact surface at the bottom of the frame to eliminate the influence of assembly gaps on force value monitoring.

5. The wheel pressure testing fixture according to claim 1, characterized in that, The outer circumferential surface of the roller is covered with a rubber layer with a thickness of 5-10 mm and a Shore hardness of 60-70 HA. The surface of the rubber layer is provided with circumferentially distributed anti-slip textures with a texture depth of 0.5-1 mm.

6. The wheel pressure testing fixture according to claim 1, characterized in that, The fixed base plate is made of steel plate, and there are 4 evenly distributed leveling bolts at the bottom. The lower end of the leveling bolts is provided with rubber pads, and the fixed base plate is provided with a waist-shaped mounting groove for fixing to the ground.

7. The wheel pressure testing fixture according to claim 1, characterized in that, The top of the frame is equipped with a level mounting base, in which a bubble level is embedded to monitor the levelness of the frame. The level has an accuracy of 0.1 mm / m.

8. A wheel pressure testing fixture according to any one of claims 1 to 7, characterized in that, The signal output terminal of the three-dimensional force sensor is connected to the data acquisition module via a shielded cable. The shielded cable is covered with a metal corrugated tube, and both ends of the corrugated tube are sealed to the sensor housing and the data acquisition module housing, respectively.

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