Variable load pavement roller

Abstract

The invention discloses a variable load pavement roller, which comprises a rack, and a walking mechanism and a load adjusting mechanism which are arranged at the lower part of the rack, and the walking mechanism comprises a front drive axle hinged to the bottom of the front side of the rack and a rear drive axle hinged to the bottom of the rear side of the rack; the load adjusting mechanism comprises a plurality of groups of loading wheels arranged between the front driving wheel and the rear driving wheel, the loading wheels are hinged to a supporting shaft, the end part of the supporting shaft is simultaneously hinged and fixed to a rocker and a crank, the other end of the crank is hinged to a crank shaft arranged on one side of the supporting shaft, and the crank shaft is hinged to the rocker. The crank shaft is hinged to a hinge seat installed on the machine frame, the other end of the rocker is hinged to the telescopic end of a loading oil cylinder arranged on the other side of the supporting shaft, the loading oil cylinder is installed on the machine frame in a hinged mode through the hinge seat, and the loading wheel exerts pressure on the road surface through the road surface rolling belt by controlling the action of the loading oil cylinder. Therefore, the road roller can quickly adjust the ground pressure.

Description

Technical Field

[0001] This invention belongs to the field of highway construction and maintenance technology, and specifically relates to a variable load road roller. Background Technology

[0002] With the continuous development of highway transportation, new materials and processes for highway construction and maintenance are constantly being updated, which also places new demands on supporting equipment. For example, pavements paved with MOH (Modular Hydrate) materials have advantages over hot-paved asphalt concrete pavements, such as low carbon emissions and environmental friendliness, a balance of rigidity and flexibility, strong water stability, and good temperature adaptability, leading to their increasingly widespread use. However, problems such as material displacement, drainage issues, and wheel sticking during the compaction process of MOH material pavements paved at room temperature cannot be effectively solved using conventional steel-drum or rubber-tired rollers. This invention designs a variable-load pavement roller that adapts to the rolling rise angle of the MOH material by changing the load during compaction, thereby improving compaction quality. This effectively solves the practical problems existing in the compaction process of asphalt pavements paved at room temperature, and can effectively promote the application of new materials and processes in highway construction and maintenance, meeting the needs of highway maintenance construction. For conventional hot asphalt concrete pavement compaction, there are already detailed process specifications. According to these specifications, achieving a good degree of compaction requires different compaction stages, including initial compaction, intermediate compaction, and final compaction. Different types and tonnages of compaction equipment must be selected and compacted at specific speeds. This makes the compaction process complex and cumbersome, resulting in high equipment and personnel costs, and increased management costs due to multiple machines operating simultaneously on-site. This invention not only meets the requirements for room-temperature paving and compaction of MOH materials but also replaces conventional road rollers for compaction operations at various stages of hot asphalt pavement, truly achieving multi-purpose functionality. Existing road compaction technologies, such as the patent document CN2016106579784, disclose a single-drum roller capable of varying compaction mass. This roller can optimally adjust its mass distribution under different working conditions. It includes an articulated front and rear frame, a steel drum mounted on the front frame for compaction, a tire mounted on the rear frame for drive, a counterweight that can be placed on either the front or rear frame, and a counterweight adjustment mechanism for changing its position. This single-drum roller uses a mechanical structure to adjust the counterweight, distributing the roller's mass, improving compaction quality and transfer efficiency. During road compaction, the counterweight is moved forward using a linkage mechanism formed by the main and auxiliary boom hydraulic cylinders, increasing the weight of the steel drum and significantly improving compaction. During transfer, the counterweight is moved backward using the same linkage mechanism, increasing the weight of the rear frame, improving traction, and enhancing driving force. However, this patent document does not describe any technology related to a press that enables rapid, stepless pressure adjustment. Summary of the Invention

[0003] The technical problem solved by this invention is to provide a variable load road roller that effectively solves the material shoving phenomenon of MOH materials during the compaction process, meeting the quality requirements of normal temperature paving and compaction. In the loose-lay state, the internal friction angle between aggregates in MOH materials is small, especially in the initial compaction state, where the material shoving phenomenon is more obvious as the roller moves. Therefore, this road roller can change the material's compaction rise angle during the initial compaction by varying the load. Simultaneously, belt compaction increases the friction between the compaction belt and the material, increasing the compaction work time for a single compaction cycle, significantly increasing the adhesion between the instantaneously compacted material and the already compacted material, thereby eliminating the material shoving phenomenon. Furthermore, this road roller can set corresponding compaction loads at different compaction stages according to process specifications. Only one variable load road roller is needed to achieve road compaction operations according to process specifications, not only reducing construction costs but also effectively reducing emissions pollution.

[0004] The key technical design features of this invention are: the designed road roller can achieve rapid and stepless adjustment of the pressure per unit area within a certain range by controlling and adjusting the area of ​​the equipment relative to the road surface; the designed road roller can effectively eliminate the shoving phenomenon on the road material caused by the excessive horizontal component of the compaction wheel of conventional road rollers at different compaction stages by adjusting the compaction climb angle; and through a closed-loop control system, this invention can achieve preset "constant load" compaction operation to address the imbalance of actual parameters during paving.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a variable load road roller, characterized in that it includes a frame and a traveling mechanism and a load adjustment mechanism disposed at the lower part of the frame, wherein the traveling mechanism includes a front drive axle hinged to the bottom front side of the frame and a rear drive axle hinged to the bottom rear side of the frame, a front drive wheel is provided on the front drive axle, a rear drive wheel is provided on the rear drive axle, and a road compaction belt is provided between the front drive wheel and the rear drive wheel to realize the connection and transmission between the front drive wheel and the rear drive wheel; the load adjustment mechanism includes a road compaction belt disposed between the front drive wheel and the rear drive wheel. The machine has multiple loading wheels, which are hinged to a support shaft. The end of the support shaft is hinged to both a rocker arm and a crank. The other end of the crank is hinged to a crankshaft located on one side of the support shaft. This crankshaft is hinged to a hinge seat mounted on the frame. The other end of the rocker arm is hinged to the telescopic end of a loading cylinder located on the other side of the support shaft. The loading cylinder is hinged to the frame via the hinge seat. The loading wheels apply pressure to the road surface through the road compaction belt, which can be achieved by controlling the movement of the loading cylinder, thereby enabling rapid adjustment of the ground pressure by the road roller.

[0006] Furthermore, the frame is equipped with an inclination sensor to detect the height difference between the front and rear drive wheels and the road surface in real time, and convert it into an electrical signal representing the inclination angle of the frame. The electrical signal is conditioned and converted by an A / D converter and then input to the intelligent controller installed on the frame. The intelligent controller compares the detected real-time inclination angle value with the preset calibrated inclination angle value, calculates the deviation, and runs a proportional-integral-derivative (PID) control algorithm or an adaptive control algorithm based on the deviation to generate control commands and output them to the electro-hydraulic proportional valves or servo valves of each loading cylinder to adjust the vertical position of the loading wheel, thereby changing the gravity distribution coefficient and effective contact area of ​​the front drive wheel, realizing constant pressure control of the front drive wheel on the ground, so that the road roller can operate according to the set constant pressure parameters at different compaction stages.

[0007] Furthermore, the frame is equipped with a center of gravity adjustment mechanism for adjusting the center of gravity position of the road roller. This center of gravity adjustment mechanism can be implemented by moving the position of the counterweight block to adjust the center of gravity position of the road roller, or it can be implemented by setting up a water tank and adjusting the center of gravity position of the road roller by loading water in the water tank at different positions.

[0008] Furthermore, the road surface compaction strip is a track or a belt.

[0009] Furthermore, the frame is equipped with multiple sets of tensioning rollers for tensioning the road surface compaction strip.

[0010] Furthermore, a power unit is provided on the upper part of the frame, which is connected to the front drive axle and / or the rear drive axle through a power transmission mechanism, the power transmission mechanism including a differential mechanism for controlling left and right steering.

[0011] Furthermore, 4 to 8 sets of loading wheels are provided between the front drive wheel and the rear drive wheel.

[0012] The present invention has the following advantages and beneficial effects:

[0013] 1. Compared to a single compaction roller, the rubber track increases the contact area with the road surface, allowing both the instantaneously compacted material and the already compacted material to simultaneously contact the compaction strip, increasing the adhesion and friction between the materials. Simultaneously, the compaction strip reduces the roller's roll angle, eliminating the displacement of loosely laid material caused by the horizontal component of the compaction roller's force at different compaction stages, thus meeting the engineering construction quality requirements.

[0014] 2. This invention changes the pressure of the roller on the road surface by controlling and adjusting the number of loading wheels and the force relative to the road surface. It can also adjust the center of gravity of the roller through the center of gravity adjustment mechanism to achieve variable load compaction and meet the various pressure requirements of different compaction stages.

[0015] 3. The variable load intelligent compaction system of this invention can monitor the compaction effect in real time and automatically adjust the working pressure parameters. By adjusting the pressure of each loading wheel on the road surface, various compaction states can be achieved to meet different compaction processes. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the present invention.

[0017] Figure 2 This is a schematic diagram illustrating the principle of the present invention.

[0018] Figure 3 This is a load distribution diagram for the present invention.

[0019] Figure 4 This is a load distribution diagram during the actual application of the present invention.

[0020] Figure 5 This is a control principle diagram of the present invention.

[0021] Figure 6 This is a schematic diagram of the road surface adjustment pressure for each wheelset in this invention.

[0022] In the diagram: 1-Front drive wheel, 2-Road compaction belt, 3-Loading wheel, 4-Loading cylinder, 5-Crankshaft, 6-Tensioning wheel, 7-Frame, 8-Front drive axle, 9-Rear drive axle, 10-Cab, 11-Power compartment, 12-Counterweight. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] See Figure 1-6 The technical solution of the present invention will be described in detail below.

[0025] like Figure 1As shown, a variable load road roller includes a frame 7 and a traveling mechanism and a load adjustment mechanism disposed at the lower part of the frame 7. The traveling mechanism includes a front drive axle 8 hinged to the bottom front side of the frame 7 and a rear drive axle 9 hinged to the bottom rear side of the frame 7. The front drive axle 8 is provided with a front drive wheel 1, and the rear drive axle 9 is provided with a rear drive wheel. A road compaction belt 2 is provided between the front drive wheel 1 and the rear drive wheel to realize the connection and transmission between the front drive wheel 1 and the rear drive wheel. The load adjustment mechanism includes multiple sets of loading wheels 3 disposed between the front drive wheel 1 and the rear drive wheel. The loading wheels 3 are hinged to a support shaft, and the end of the support shaft is simultaneously hinged to a rocker arm. The crank and the rocker arm are connected, with the other end of the crank arm hinged to the crankshaft 5 located on one side of the support shaft. The crankshaft 5 is hinged to the hinge seat mounted on the frame 7. The other end of the rocker arm is hinged to the telescopic end of the loading cylinder 4 located on the other side of the support shaft. The loading cylinder 4 is hinged to the frame 7 via the hinge seat. The loading wheel 3 applies pressure to the road surface through the road compaction belt 2, which can be achieved by controlling the action of the loading cylinder 4. The counterweight 12 is a component of the center of gravity adjustment mechanism in the entire road roller. By moving back and forth on the frame 7, the center of gravity of the entire road roller is adjusted, thereby achieving rapid adjustment of the ground pressure of the road roller.

[0026] In the specific use of this invention: the road compaction belt 2 is a track or belt; multiple sets of tensioning wheels 6 are installed on the frame 7 for tensioning the road compaction belt 2 from the outside; the upper part of the frame 7 is provided with a cab 10 and a power compartment 11, the power compartment 11 is provided with a power device for driving the front drive wheel 1 and / or the rear drive wheel to rotate, the power device is connected to the front drive axle and / or the rear drive axle through a power transmission mechanism, the power transmission mechanism includes a differential mechanism for controlling left and right steering; four sets of loading wheels 3 are provided between the front drive wheel 1 and the rear drive wheel.

[0027] Variable load rolling construction instructions: The drive wheel and the loading wheel apply pressure to the paved road surface through a belt / track. The pressure on the road surface is adjusted by increasing or decreasing the force applied to the ground by the loading wheel.

[0028] like Figure 2 As shown, the total pressure applied to the road surface by the road roller is:

[0029]

[0030] Wherein: F i A is the force distributed by the weight of the road roller to a single wheel. i The effective area of ​​a single wheel pressed onto the road surface by the belt.

[0031] The pressure distributed on each wheel (drive wheel and load wheel) is different, and although the effective area of ​​each wheel pressing onto the road surface through the belt is also different, the difference is not significant. For ease of explanation and calculation, all are denoted as A.

[0032] A≈A i (i = 1, 2, 3...)

[0033]

[0034] Where: G is the weight of the road roller; M is the total mass of the road roller.

[0035] The front and rear drive wheels are always in contact with the ground and exert force. When the load wheels are all lifted, the pressure on the road surface is the greatest.

[0036]

[0037] When all the loading wheels are in contact with the ground and exerting force, the pressure on the road surface is minimal.

[0038]

[0039] P max =3P min

[0040] Variable load construction allows for adjustable pressure on the road roller within a certain range, meaning the force applied to the ground by the loading wheels can be adjusted. When individual loading wheels bottom out, the pressure on the road surface can be adjusted between maximum and minimum. Furthermore, the actual bottom-out pressure of the loading wheels can also be adjusted, i.e., A... i It is not exactly equal to A, which theoretically explains the stepless adjustment.

[0041] By adjusting the road surface pressure (i.e., the pressure exerted by the roller on the road surface) on each wheel pair, various load combinations of the roller can be achieved. Some of these combinations include... Figure 6As shown in the diagram: A: Both the drive wheel and the loading wheel are on the ground, and the loading wheel is adjusted so that its pressure on the road surface is the same as that of the drive wheel. At this point, the roller's pressure on the ground is minimal. a: Both the drive wheel and the loading wheel are on the ground, and the loading wheel is adjusted so that its pressure on the road surface is greater than that of the drive wheel. B: The drive wheel and the two loading wheels at the front and rear are on the ground, while the two middle loading wheels are not. The loading wheels on the ground are adjusted so that their pressure on the road surface is the same as that of the drive wheel. b: Both the drive wheel and the loading wheel are on the ground, and the two middle loading wheels are adjusted so that their pressure on the road surface is less than that of the drive wheel and the other two loading wheels. C: The drive wheel and the two middle loading wheels are on the ground, while the two front and rear loading wheels are not. The loading wheels on the ground are adjusted so that their pressure on the road surface is the same as that of the drive wheel. c: Both the drive wheel and the loading wheel are on the ground, and the two front and rear loading wheels are adjusted so that their pressure on the road surface is less than that of the drive wheel and the other two loading wheels. D: The drive wheel is on the ground, but the loading wheel is not. At this point, the roller's pressure on the ground is maximum. d: Both the drive wheel and the loading wheel are on the ground, and the loading wheel is adjusted so that its pressure on the road surface is less than that of the drive wheel. The use of multiple load combinations can meet the equipment requirements of different compaction stages after the MOH material is laid.

[0042] Because of the combined effect of traction and the forward pressure of the paved material during compaction, traditional rollers cause a certain degree of "shoving" of the paved surface during compaction. Tracked rollers, on the other hand, exert more widespread pressure on the material due to the tracks, although it is not a uniformly distributed load (e.g., ...). Figure 3 (As shown), but the friction of the track and the adhesion between the materials can reduce and avoid the "pushing" phenomenon during rolling.

[0043] Hot-laid asphalt concrete (HMA) suspended dense structures (such as AC gradation) typically have a low internal friction angle (approximately 30°–35°) due to the high content of fine aggregates. Furthermore, the bonding strength of hot asphalt is significantly higher than that of emulsified asphalt, resulting in less noticeable shoving during compaction. In contrast, MOH materials are made by adding cement (1%–3% of aggregate mass) to cold recycled emulsified asphalt. The cement hydration products (such as CSH gel) form a rigid skeleton with the aggregates, significantly increasing the internal friction angle (approaching or exceeding 40°). The bonding strength primarily comes from the demulsification of the emulsified asphalt and the cement hydration bonding effect. However, these conditions are largely absent during the initial compaction stage after paving. Therefore, conventional paving during the initial compaction stage easily leads to shear slippage of the mixture under rolling loads. To reduce material slippage, it is necessary to reduce the horizontal component of the rolling load. Using low-pressure band compaction can reduce the depth of wheel compaction sinking into the loose material, and the roll rise angle can be reduced by more than 30%. By varying the load and gradually increasing it through multi-stage static compaction, excessive impact force can be avoided, which can lead to aggregate displacement.

[0044] pass Figure 3As can be seen, the compaction strip significantly increases the area and range of friction applied by the roller to the road surface, unlike traditional rollers where only the wheel flange contacts the road surface in a limited area. This allows both the instantaneously compacted material and the already compacted material to simultaneously contact the compaction strip, increasing the adhesion and friction between the materials. Simultaneously, the compaction strip reduces the pressure rise angle of the roller, thus eliminating or mitigating the shoving of the loosely laid material caused by the horizontal component of the compaction wheel's force during initial compaction.

[0045] This road roller can achieve preset "constant load" compaction operation of the front drive wheel through a closed-loop control system.

[0046]

[0047] F1==kG

[0048] Where: P 恒 The constant pressure preset in the early calibration; F1 is the gravity at the front drive wheel; A1 is the effective area of ​​the belt contacting the ground at the front drive wheel; G is the total gravity of the roller; k is the gravity distribution coefficient of the front drive wheel, with a value range of 1 / 6 to 1 / 2.

[0049] For a preset constant pressure P 恒 By adjusting the vertical position of the loading wheel, the gravity distribution coefficient k and the effective contact area A1 of the front drive wheel are dynamically changed, thereby achieving precise constant pressure control of the front drive wheel on the road surface. The position adjustment of the loading wheel is executed by the loading cylinder, and the cylinder action is controlled in real time by a tilt sensor mounted on the frame in a closed loop. The tilt sensor is used to detect the height difference between the front and rear drive wheels relative to the compacted road surface and convert it into an angle signal a (see...). Figure 4 The signal is first processed by a signal conditioning module for anti-aliasing low-pass filtering, temperature drift compensation, and amplification to suppress measurement errors caused by construction vibration, electromagnetic interference, and environmental temperature differences. Then, it is input to the on-board industrial controller. The controller compares the real-time measured value 'a' with the calibrated setpoint 'a0' to obtain the deviation Δa, and runs a proportional-integral-derivative (PID) adaptive control algorithm based on this deviation: the proportional element (P) generates a rapid adjustment based on the current deviation magnitude to achieve immediate response; the integral element (I) accumulates and corrects the deviation to eliminate steady-state error; and the derivative element (D) predicts the deviation change trend to suppress overshoot and oscillation caused by uneven material distribution or road surface fluctuations during construction.

[0050] In adaptive mode, the intelligent controller dynamically adjusts the PID parameter weights based on road material type, construction stage, and vehicle speed to improve system adaptability and control accuracy. Finally, the intelligent controller outputs the comprehensively calculated control signal to the electro-hydraulic proportional valve drive module, precisely adjusting the inlet and outlet oil flow of the loading cylinder, thereby achieving stepless adjustment of the loading wheel position and ground pressure. When the detected value 'a' is less than the preset value 'a0', the system automatically determines that the road surface has reached the preset compaction state and sends a prompt signal to the operator through the onboard human-machine interface (HMI) and audible and visual alarm devices, enabling the operator to monitor the road surface compaction degree in real time during construction. This electro-hydraulic closed-loop control strategy can compensate for the compaction difference between the entire machine passing and only the front wheels passing, ensuring that constant pressure operation achieves the expected results at different compaction stages, thereby significantly improving the compaction uniformity and construction quality of MOH materials and ambient temperature paved roads. For the specific control process, please refer to [link to specific details]. Figure 5 .

[0051] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A variable load road roller, characterized in that... The machine includes a frame and a traveling mechanism and a load adjustment mechanism located at the bottom of the frame. The traveling mechanism includes a front drive axle hinged to the bottom front side of the frame and a rear drive axle hinged to the bottom rear side of the frame. The front drive axle has a front drive wheel, and the rear drive axle has a rear drive wheel. A road compaction belt is provided between the front and rear drive wheels to enable transmission between them. The load adjustment mechanism includes multiple sets of loading wheels located between the front and rear drive wheels. The loading wheels are hinged to a support shaft. The end of the support shaft is hinged to both a rocker arm and a crank. The other end of the crank is hinged to a crankshaft located on one side of the support shaft. The crankshaft is hinged to a hinge seat mounted on the frame. The other end of the rocker arm is hinged to the telescopic end of a loading cylinder located on the other side of the support shaft. The loading cylinder is hinged to the frame via the hinge seat. The loading wheels apply pressure to the road surface through the road compaction belt, which can be achieved by controlling the movement of the loading cylinder, thereby enabling rapid adjustment of the ground pressure by the road roller.

2. The variable load road roller according to claim 1, characterized in that: The frame is equipped with tilt sensors to detect the height difference between the front and rear drive wheels and the road surface in real time, and convert it into an electrical signal representing the tilt angle of the frame. The electrical signal is conditioned and converted by an A / D converter and then input to an intelligent controller mounted on the frame. The intelligent controller compares the detected real-time tilt angle value with a preset calibrated tilt angle value, calculates the deviation, and runs a proportional-integral-derivative (PID) control algorithm or an adaptive control algorithm based on the deviation to generate control commands and output them to the electro-hydraulic proportional valves or servo valves of each loading cylinder to adjust the vertical position of the loading wheel, thereby changing the gravity distribution coefficient and effective contact area of ​​the front drive wheel, realizing constant pressure control of the front drive wheel on the ground, so that the road roller can operate according to the set constant pressure parameters at different compaction stages.

3. The variable load road roller according to claim 1, characterized in that: The frame is equipped with a center of gravity adjustment mechanism for adjusting the center of gravity position of the road roller. The center of gravity adjustment mechanism can be implemented by moving the counterweight block to adjust the center of gravity position of the road roller, or by setting up a water tank and adjusting the center of gravity position of the road roller by loading water in the water tank at different positions.

4. The variable load road roller according to claim 1, characterized in that: The road surface compaction strip is a track or belt.

5. The variable load road roller according to claim 1, characterized in that: The frame is equipped with multiple sets of tensioning rollers for tensioning the road surface compaction strip.

6. The variable load road roller according to claim 1, characterized in that: The upper part of the frame is equipped with a power unit, which is connected to the front drive axle and / or the rear drive axle through a power transmission mechanism. The power transmission mechanism includes a differential mechanism for controlling left and right steering.

7. The variable load road roller according to claim 1, characterized in that: There are 4 to 8 sets of loading wheels between the front drive wheel and the rear drive wheel.

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