A tension control method for the rubber track tensioning mechanism of an excavator

Abstract

This invention discloses a tensioning control method for a rubber track tensioning mechanism of an excavator, belonging to the field of excavator track control technology. The tensioning mechanism includes: a controller that controls a tensioning wheel to tension the rubber track via a drive motor; and a displacement sensor installed on the excavator body, vertically aligned with the slack section of the rubber track, used to detect the actual sagging of the rubber track. The control method includes: establishing a dynamic variation model of the theoretical tension force Ft based on the material characteristics of the rubber track, including a temperature compensation coefficient and an aging attenuation factor; the controller controlling the tensioning wheel to tension the rubber track according to the theoretical tension force Ft; and through dual-factor modeling of temperature and aging and multi-condition closed-loop control, systematically solving the static defects of traditional fixed tension, realizing dynamic optimization of track tension throughout its entire life cycle, and improving equipment safety, reliability, and maintenance efficiency.

Description

Technical Field

[0001] This invention relates to the field of excavator track control technology, and in particular to a tension control method for an excavator rubber track tensioning mechanism. Background Technology

[0002] Current excavator rubber track tension control technology generally adopts a fixed tension design, the core drawback of which is its inability to cope with the fluctuations in the elastic properties of the rubber material caused by temperature changes and aging. Specifically:

[0003] First, the impact of temperature on the elasticity of rubber tracks has not been effectively addressed. Rubber materials exhibit significant temperature sensitivity: in low-temperature environments (e.g., -20°C), the mobility of rubber molecular chains decreases, the elastic modulus increases significantly, and the track exhibits hardening characteristics. If the tension is kept constant at this temperature, the sag in the slack section of the track will exceed a safe range due to increased material rigidity, leading to slippage and derailment risks during operation. Conversely, in high-temperature environments (e.g., 60°C), the rubber molecular chains soften, the elastic modulus decreases, and a fixed tension may subject the track to excessive tensile stress, causing cord breakage or rubber layer tearing. However, existing tensioning mechanisms lack temperature sensing and compensation mechanisms, failing to dynamically adjust the tension according to ambient temperature, resulting in a significantly higher failure rate of tracks under extreme temperature conditions.

[0004] Secondly, the aging and degradation of rubber tracks has not been quantitatively controlled. With increasing cumulative usage time, the rubber molecular chains gradually break, causing irreversible permanent deformation and a continuous decline in elasticity. For example, after 1000 hours of use, a natural rubber track can experience a permanent tensile deformation of 3-5 mm. If the tension remains at its initial value, the actual track tension will be significantly reduced, affecting the equipment's traction and stability. Current technology relies on manual periodic checks of track sagging and manual adjustment of tension. However, manual inspection suffers from high subjectivity, long cycles, and low accuracy, making it difficult to track the rubber aging process in real time. This leads to delayed maintenance and further exacerbates abnormal track wear.

[0005] Furthermore, fixed tension cannot adapt to diverse working conditions. Excavators experience significantly different dynamic loads on their tracks during various operating scenarios, such as high-speed travel and bucket digging. For example, at high speeds, the instantaneous acceleration of the tracks increases, and the fixed tension may cause sagging fluctuations to exceed safe limits, leading to frequent malfunctions of the tensioning mechanism. Conversely, during low-speed, precision operations (such as leveling the ground), insufficient precision may result in unstable track tension, affecting work quality. Existing technologies lack the ability to dynamically respond to changes in working conditions, making it difficult to achieve a balance between stability and precision. Summary of the Invention

[0006] The purpose of this invention is to solve the above-mentioned problems by providing a tension control method for the tensioning mechanism of excavator rubber tracks.

[0007] The technical solution of this invention is implemented as follows:

[0008] This invention provides a tension control method for a rubber track tensioning mechanism of an excavator, the tensioning mechanism comprising:

[0009] The controller uses a drive motor to control the tensioning wheel to tension the rubber track.

[0010] The displacement sensor, mounted on the excavator's body and vertically aligned with the slack section of the rubber track, is used to detect the actual sagging of the rubber track. ;

[0011] The control method includes:

[0012] Based on the material properties of rubber tracks, a dynamic variation model of the theoretical tension force Ft, including temperature compensation coefficient and aging attenuation factor, is established. The controller controls the tensioning wheel to tension the rubber track according to the theoretical tension force Ft, and reads the actual sagging of the rubber track from the displacement sensor in real time. ; and with theoretical droop amount Compare the two and calculate the deviation rate;

[0013] If the deviation rate exceeds the threshold, the controller controls the tensioning wheel to perform secondary tensioning on the rubber track until the actual sagging amount is reached. Tendency towards theoretical droop Inside;

[0014] The model expression is: Where Ft is the theoretical tension force, F0 is the reference tension force; T is the real-time temperature, T0 is the reference temperature, k1 is the temperature influence coefficient; t is the cumulative usage time, k2 is the aging attenuation coefficient.

[0015] In one embodiment, the deviation rate is calculated as follows: ;

[0016] when If the controller determines that the sag is too large and the tension is insufficient, it will control the tension wheel to increase the tension.

[0017] when If the controller determines that the sag is too small and the tension is too large, it will control the tension wheel to reduce the tension.

[0018] The The positive threshold is +5% to +10%, and the negative threshold is -5% to -10%.

[0019] In one implementation, when the track speed v exceeds a speed threshold or the acceleration a exceeds an acceleration threshold, the The set threshold is temporarily adjusted to ±15%;

[0020] When the track speed v is lower than the speed threshold and the acceleration a is lower than the acceleration threshold, the set threshold of the deviation rate is restored to the default value, which is ±5% to ±10%.

[0021] In one embodiment, the temperature compensation coefficient k1 is obtained by fitting the elastic modulus test data of the rubber material at different temperatures;

[0022] The aging attenuation coefficient k2 is obtained by fitting historical statistical data of the cumulative service time of the track and the amount of permanent tensile deformation.

[0023] In one implementation, when t reaches a preset aging cycle, the controller automatically triggers a tension compensation program.

[0024] In one embodiment, the preset aging cycle is adjusted according to the material of the rubber track;

[0025] If the material of the rubber track is natural rubber, the initial value of the preset aging cycle is 800 to 1200 hours;

[0026] If the material of the rubber track is synthetic rubber, the initial value of the preset aging cycle is 500 to 800 hours.

[0027] In one embodiment, the excavator is also equipped with a timer for recording the duration of the rubber tracks, which includes the effective working time and the idling time, wherein the cumulative usage time t only includes the effective working time;

[0028] The condition for determining the effective working time is: the track speed v > 0.5 km / h and lasts for more than 5 minutes;

[0029] The idling time is determined by the following conditions: track speed v ≤ 0.5 km / h and duration not exceeding 5 minutes.

[0030] In one embodiment, when the idling time exceeds 30 minutes, a sleep mode is automatically triggered. In the sleep mode, the timer stops counting, and the tension wheel maintains the current tension.

[0031] The advantages or beneficial effects of the above technical solutions include at least the following:

[0032] 1. Temperature-sensitive dynamic compensation mechanism:

[0033] The invention establishes a linear correlation model between tension and ambient temperature by introducing a temperature compensation coefficient (k1). When the ambient temperature deviates from the baseline value (e.g., 25℃), the tension automatically adjusts: in low-temperature environments, the tension increases proportionally with decreasing temperature to compensate for the relaxation tendency caused by rubber hardening; in high-temperature environments, the tension decreases proportionally with increasing temperature to avoid the risk of overload caused by rubber softening. For example, in a -10℃ low-temperature condition, the tension can automatically increase by 10%-15%, ensuring that the track sag remains within the safe threshold. Compared with traditional fixed tension, the risk of low-temperature slippage is reduced by more than 60%.

[0034] 2. Quantitative tracking and compensation for aging degradation:

[0035] The invention achieves dynamic tension management throughout the entire lifecycle of tracks by using an aging attenuation coefficient (k2) and preset aging cycles (e.g., 800-1200 hours for natural rubber and 500-800 hours for synthetic rubber). The cumulative usage time serves as a quantitative indicator of aging. When the preset cycle is reached, the system automatically triggers a tension compensation program to counteract the effects of rubber elasticity decay. For example, after 1000 hours of use, the system can automatically increase the tension by 5%-8%, restoring the track sag to its initial accuracy range. Compared to manual maintenance, abnormal wear caused by aging is reduced by 40%, and track life is extended by 15%-20%.

[0036] 3. Droop closed-loop control and multi-condition adaptive control:

[0037] The invention uses a displacement sensor to collect the real-time sag (ΔL) of the track during the slack section and dynamically compares it with the theoretical sag (ΔLt). Based on the deviation rate formula (e), it achieves closed-loop adjustment of the tension. Under default operating conditions, the system uses ±5% to ±10% as a deviation threshold to ensure tension accuracy at the millimeter level. When the track speed or acceleration exceeds the threshold (e.g., v > 5 km / h or a > 0.5 m / s²), the tension is adjusted accordingly. 2 The threshold is automatically widened to ±15%, reducing the adjustment frequency under high-speed conditions and improving driving stability. Actual test data shows that this mechanism reduces the frequency of tension adjustment under complex conditions by 30% and saves approximately 10% on equipment energy consumption.

[0038] 4. Material differentiation adaptation and intelligent management:

[0039] This invention addresses the differences in properties between natural and synthetic rubber by providing material-specific parameter configurations: natural rubber tracks utilize a lower temperature compensation coefficient (k1) and a longer aging cycle, while synthetic rubber tracks employ a higher temperature sensitivity parameter and a shorter aging cycle, ensuring optimal tension control for tracks of different materials. Simultaneously, the system accurately calculates cumulative usage time by distinguishing between effective working time (v > 0.5 km / h for ≥ 5 minutes) and idling time. Furthermore, it triggers a sleep mode when idling exceeds 30 minutes, pausing the timer while maintaining tension.

[0040] 5. Improved maintenance efficiency and security:

[0041] The invention uses a controller to record data such as temperature, duration, and sagging in real time, establishing a track condition trend analysis model. This model can provide early warnings of potential risks such as accelerated aging and sensor malfunctions (e.g., an alarm is triggered when the measured value of k2 fluctuates by more than 20%), reducing the frequency of manual inspections by more than 30%. Simultaneously, the secondary tensioning mechanism effectively suppresses the risk of excessive sagging, reducing the incidence of safety accidents such as track detachment and breakage by 80%, significantly improving operational safety and reliability. Attached Figure Description

[0042] The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the principles of the invention. These drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification.

[0043] Figure 1 A schematic diagram of the installation position of the displacement sensor according to an embodiment of the present invention is shown;

[0044] Figure 2 A schematic diagram of the excavator structure according to an embodiment of the present invention is shown.

[0045] Reference numerals: 1. fuselage; 11. displacement sensor; 111. sensor; 2. rubber track. Detailed Implementation

[0046] Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While some embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the invention. It should be understood that the accompanying drawings and embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the invention.

[0047] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other. The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0048] A tension control method for a rubber track tensioning mechanism of an excavator, the tensioning mechanism comprising:

[0049] The controller, through the drive motor, controls the tensioning wheel to tension the rubber track 2;

[0050] Displacement sensor 11 is mounted on the excavator body 1, vertically aligned with the slack section of the rubber track 2, and is used to detect the actual sagging of the rubber track 2. Specifically, the displacement sensor 11 has several sensors 111 installed at the vertical height of the body 1, such as... Figure 1 As shown, when the rubber track 2 is in front of the sensor 111, the sensor 111 senses that there is a rubber track 2 in front of it. The amount of sagging of the rubber track 2 can be determined based on the position of the sensor 111 in the height direction of sensing the rubber track 2.

[0051] The control method includes:

[0052] Based on the material properties of the rubber track 2, a theoretical tension force dynamic change model including temperature compensation coefficient and aging attenuation factor is established; the controller controls the tensioning wheel to tension the rubber track 2 according to the theoretical tension force Ft, and reads the actual sagging of the rubber track 2 in real time from the displacement sensor 11. ; and with theoretical droop amount Compare the two and calculate the deviation rate.

[0053] If the deviation rate exceeds the threshold, the controller controls the tensioning wheel to perform secondary tensioning on the rubber track 2 until the actual sagging amount is reached. Tendency towards theoretical droop Inside;

[0054] The model expression is as follows: Where Ft is the theoretical tension force, F0 is the reference tension force; T is the real-time temperature, T0 is the reference temperature, k1 is the temperature influence coefficient; t is the cumulative usage time, k2 is the aging attenuation coefficient.

[0055] The temperature compensation coefficient k1 in the model expression is obtained by fitting the elastic modulus test data of rubber material at different temperatures, taking the material of rubber track 2 as natural rubber and the reference temperature as 25℃ as an example; as shown in Table 1:

[0056] Table 1

[0057]

[0058] Linear regression yielded k1 = -0.006 / ℃; (for every 1℃ increase in temperature, the tension decreases by 0.6%).

[0059] When the real-time temperature T = 40℃, Ft = F0 × [1 0.008×(40-25)]=F0×1.318, which means the tension is 13% higher than the reference value.

[0060] The aging attenuation coefficient k2 is obtained by fitting historical statistical data of the cumulative service time of the track and the amount of tensile permanent deformation: taking natural rubber track 2 as an example; as shown in Table 2:

[0061] Table 2

[0062]

[0063] Logarithmic regression yielded k2 = 0.0022; (tension decreases by 0.22% for every hour of cumulative use).

[0064] When t = 1200 hours, ;

[0065] Furthermore, the aforementioned theoretical droop amount ;in, This is the theoretical droop amount. T is the theoretical tension force, T is the real-time temperature, T0 is the reference temperature, k1 is the temperature influence coefficient, t is the cumulative usage time, k2 is the aging attenuation coefficient, L is the track span, E is the rubber elastic modulus, and I is the moment of inertia of the section. It should be noted that the track span, rubber elastic modulus, and moment of inertia of the section all need to be input into the controller in advance.

[0066] Obtaining the theoretical droop Next, it needs to be compared with the actual sag measured by displacement sensor 11. Compare the two and calculate the deviation rate:

[0067] The deviation rate is calculated as follows: ;

[0068] when If the controller determines that the sag is too large and the tension is insufficient, it will control the tension wheel to increase the tension.

[0069] when If the controller determines that the sag is too small and the tension is too large, it will control the tension wheel to reduce the tension.

[0070] The The positive threshold is +5% to +10%, and the negative threshold is -5% to -10%; (the example uses the median value ±8%).

[0071] In the following example, the reference tension F0 = 60kN, track span L = 4m, elastic modulus E = 7MPa, and moment of inertia I = 0.006m are set.4 .

[0072] Example calculation:

[0073] I. Theoretical tension in different scenarios:

[0074] 1. Baseline operating conditions (T=25℃, t<1000 hours):

[0075] Ft=F0=60;

[0076] 2. High-temperature scenario (T=40℃, t=0 hours):

[0077] Ft=60×[1-0.006×(40-25)]×[1-0.0022×ln(0+1)]=60×0.91×1=54.6kN;

[0078] Tension decreases by 9% at high temperatures (due to a decrease in the elastic modulus of the rubber).

[0079] 3. Aging scenario (T=25℃, t=1000 hours):

[0080] Ft=60×[1-0]×[1-0.0022×ln(1000+1)]≈60×0.93=55.8kN;

[0081] After 1000 hours of cumulative use, the tension decreased by 7% (due to rubber aging and deformation).

[0082] 4. Combined effects of high temperature and aging:

[0083] Conditions: Ambient temperature T=50℃, cumulative usage time t=800 hours;

[0084] Ft=60×[1-0.006×(50-25)]×[1-0.0022×ln(800+1)]≈48.1kN;

[0085] Under certain extreme working conditions, it also has a protective mechanism. For example, if the ambient temperature T=65℃, which is outside the normal operating range, and the track load exceeds 120% of the rated value, the tension force is forced to F0×0.8=48kN to reduce track tensile stress and limit track speed. .

[0086] II. Calculation of Deviation Rate e and Tension Adjustment:

[0087] Measured: Actual sagging amount =2.2mm, calculate ;

[0088] ;

[0089] Action: The controller increases the tension by driving the tension wheel via the drive motor;

[0090] Until: ;

[0091] Measured: Actual sagging amount =1.6mm, calculate ;

[0092] ;

[0093] Action: The controller drives the tensioning wheel via the drive motor to reduce the tension;

[0094] Until: And so on.

[0095] Based on the above, when the track speed v exceeds the speed threshold or the acceleration a exceeds the acceleration threshold, the set threshold is temporarily adjusted to ±15%;

[0096] When the track speed v is lower than the speed threshold and the acceleration a is lower than the acceleration threshold, the set threshold of the deviation rate is restored to the default value, which is ±5% to ±10%.

[0097] Based on the above further improvements, when t reaches the preset aging cycle, the controller automatically triggers the tension compensation program, wherein the preset aging cycle is adjusted according to the material of the rubber track 2;

[0098] If the material of the rubber track 2 is natural rubber, the initial value of the preset aging cycle is 800 to 1200 hours;

[0099] If the material of the rubber track 2 is synthetic rubber, the initial value of the preset aging cycle is 500 to 800 hours;

[0100] The excavator is also equipped with a timer to record the duration of the rubber track 2. This duration includes the effective working time and the idling time. The cumulative usage time t only includes the effective working time. The effective working time is determined by the following conditions: track speed v > 0.5 km / h and lasts for more than 5 minutes. The idling time is determined by the following conditions: track speed v ≤ 0.5 km / h and lasts for no more than 5 minutes.

[0101] When the idling time exceeds 30 minutes, the sleep mode is automatically triggered. In the sleep mode, the timer stops counting, and the tension wheel maintains the current tension.

[0102] After replacing the tracks with new natural rubber tracks, the controller executes the following: reset the cumulative duration t=0, restore the aging attenuation coefficient k2 to the initial value of 0.0022; require the operator to input the track material type, such as natural rubber, and automatically load the corresponding k1=-0.006 / ℃ and aging cycle of 1000 hours.

[0103] In the description of this invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0104] Those skilled in the art should understand that the above embodiments are merely for illustrating the present invention and are not intended to limit the scope of the invention. Those skilled in the art can make other changes or modifications based on the above disclosure, and these changes or modifications still fall within the scope of the present invention.

Claims

1. A tension control method for a rubber track tensioning mechanism of an excavator, characterized in that: The tensioning mechanism includes: The controller uses a drive motor to control the tensioning wheel to tension the rubber track. The displacement sensor, mounted on the excavator's body and vertically aligned with the slack section of the rubber track, is used to detect the actual sagging of the rubber track. ; The control method includes: Based on the material properties of rubber tracks, a dynamic variation model of the theoretical tension force Ft, including temperature compensation coefficient and aging attenuation factor, is established. The controller controls the tensioning wheel to tension the rubber track according to the theoretical tension force Ft, and reads the actual sagging of the rubber track from the displacement sensor in real time. ; and with theoretical droop amount Compare the two and calculate the deviation rate; If the deviation rate exceeds the threshold, the controller controls the tensioning wheel to perform secondary tensioning on the rubber track until the actual sagging amount is reached. Tendency towards theoretical droop Inside; The model expression is: Where Ft is the theoretical tension force, F0 is the reference tension force; T is the real-time temperature, T0 is the reference temperature, k1 is the temperature influence coefficient; t is the cumulative usage time, k2 is the aging attenuation coefficient.

2. The tension control method for the excavator rubber track tensioning mechanism according to claim 1, characterized in that: The deviation rate is calculated as follows: ; when If the controller determines that the sag is too large and the tension is insufficient, it will control the tension wheel to increase the tension. when If the controller determines that the sag is too small and the tension is too large, it will control the tension wheel to reduce the tension. The The positive threshold is +5% to +10%, and the negative threshold is -5% to -10%.

3. The tension control method for the excavator rubber track tensioning mechanism according to claim 2, characterized in that: When the track speed v exceeds the speed threshold or the acceleration a exceeds the acceleration threshold, the The set threshold is temporarily adjusted to ±15%; When the track speed v is lower than the speed threshold and the acceleration a is lower than the acceleration threshold, the set threshold of the deviation rate is restored to the default value, which is ±5% to ±10%.

4. The tension control method for the excavator rubber track tensioning mechanism according to claim 1, characterized in that: The temperature compensation coefficient k1 is obtained by fitting the elastic modulus test data of rubber material at different temperatures; The aging attenuation coefficient k2 is obtained by fitting historical statistical data of the cumulative service time of the track and the amount of permanent tensile deformation.

5. The tension control method for the excavator rubber track tensioning mechanism according to claim 1, characterized in that: When t reaches the preset aging cycle, the controller automatically triggers the tension compensation program.

6. The tension control method for the excavator rubber track tensioning mechanism according to claim 5, characterized in that: The preset aging cycle is adjusted according to the material of the rubber track; If the material of the rubber track is natural rubber, the initial value of the preset aging cycle is 800 to 1200 hours; If the material of the rubber track is synthetic rubber, the initial value of the preset aging cycle is 500 to 800 hours.

7. The tension control method for the excavator rubber track tensioning mechanism according to claim 6, characterized in that: The excavator is also equipped with a timer to record the duration of the rubber tracks, which includes the effective working time and the idling time. The cumulative usage time t only includes the effective working time. The condition for determining the effective working time is: the track speed v > 0.5 km / h and lasts for more than 5 minutes; The idling time is determined by the following conditions: track speed v ≤ 0.5 km / h and duration not exceeding 5 minutes.

8. The tension control method for the excavator rubber track tensioning mechanism according to claim 7, characterized in that: When the idling time exceeds 30 minutes, the sleep mode is automatically triggered. In the sleep mode, the timer stops counting, and the tension wheel maintains the current tension.

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