Tensioning control method of excavator rubber track tensioning mechanism

Abstract

The invention discloses a tensioning control method of an excavator rubber belt track tensioning mechanism, and belongs to the technical field of excavator belt track control, the tensioning mechanism comprises a controller, a tensioning wheel, a tensioning wheel, a tensioning wheel, a tensioning wheel, a tensioning wheel and a tensioning wheel, the displacement sensor is mounted on a machine body of the excavator, is vertically aligned with the loose section of the rubber crawler belt and is used for detecting the actual sagging amount # imgabs0 # of the rubber crawler belt; the control method comprises the following steps: establishing a theoretical tension Ft dynamic change model containing a temperature compensation coefficient and an aging attenuation factor according to the material characteristics of the rubber track; the controller controls the tensioning wheel to tension the rubber track according to the theoretical tensioning force Ft; by means of temperature and aging two-factor modeling and multi-working-condition closed-loop control, the static defect of traditional fixed tension is systematically overcome, full-life-cycle dynamic optimization of crawler belt tension is achieved, and equipment safety, reliability and maintenance efficiency are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of excavator crawler control, and particularly to a tension control method for a tensioning mechanism of an excavator rubber crawler. Background Art

[0002] The existing tension control technology for excavator rubber crawlers generally adopts a fixed tension design, and its core defect is that it cannot cope with the elastic characteristic fluctuations caused by temperature changes and aging attenuation of rubber materials. Specifically: First, the influence of temperature on the elasticity of rubber crawlers has not been effectively solved. Rubber materials have significant temperature sensitivity: in a low-temperature environment (such as -20°C), the activity of rubber molecular chains decreases, the elastic modulus increases significantly, and the crawler shows a hardening characteristic. At this time, if the tension force remains fixed, the sag amount of the slack section of the crawler will exceed the safety range due to the increased rigidity of the material, resulting in risks of slipping and derailing during driving; while in a high-temperature environment (such as 60°C), the rubber molecular chains soften and the elastic modulus decreases. The fixed tension force may cause the crawler to bear excessive tensile stress, leading to cord breakage or rubber layer tearing. However, the existing tensioning mechanism lacks a temperature sensing and compensation mechanism and cannot dynamically adjust the tension force according to the ambient temperature, resulting in a significant increase in the failure rate of the crawler under extreme temperature conditions.

[0003] Second, the aging attenuation of rubber crawlers has not achieved quantitative control. As the cumulative usage time increases, the rubber molecular chains gradually break, the crawler will produce irreversible permanent deformation, and the elastic performance continues to decline. For example, after a natural rubber crawler is used for 1000 hours, the tensile permanent deformation amount can reach 3 - 5 mm. If the tension force still maintains the initial value, the actual tension degree of the crawler will be greatly reduced, affecting the traction force and stability of the equipment. The existing technology relies on manual regular inspection of the crawler sag amount and manual adjustment of the tension force, but manual detection has problems such as strong subjectivity, long cycle, and low accuracy, making it difficult to track the rubber aging process in real time, resulting in maintenance lag and further exacerbating the abnormal wear of the crawler.

[0004] In addition, the fixed tension degree cannot adapt to the requirements of multiple working conditions. When the excavator is in different working scenarios such as high-speed driving and bucket excavation, the dynamic loads borne by the crawler are significantly different. For example, when driving at high speed, the instantaneous acceleration of the crawler increases, and the fixed tension force may cause the sag amount fluctuation to exceed the safety range, triggering frequent malfunction of the tensioning mechanism; while in low-speed fine operations (such as leveling the ground), the fixed tension degree may cause the crawler tension force to be unstable due to insufficient accuracy, affecting the operation quality. The existing technology lacks the dynamic response ability to working condition changes and is difficult to achieve a balance between stability and accuracy. Summary of the Invention

[0005] The purpose of the present invention is to solve the above problems and provide a tension control method for a tensioning mechanism of an excavator rubber crawler.

[0006] The technical solution of the present invention is realized as follows: The present invention provides a tension control method for a tensioning mechanism of an excavator rubber track. The tensioning mechanism includes: A controller that controls a tensioning wheel to tension the rubber track through a driving motor; A displacement sensor installed on the body of the excavator, vertically aligned with the slack section of the rubber track, for detecting the actual sag of the rubber track ; The control method includes: According to the material characteristics of the rubber track, a dynamic change model of the theoretical tension force Ft including a temperature compensation coefficient and an 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 sag of the rubber track detected by the displacement sensor in real time ; and compares it with the theoretical sag to calculate the deviation rate between the two; If the deviation rate exceeds the threshold, the controller controls the tensioning wheel to perform secondary tensioning on the rubber track until the actual sag tends to the theoretical sag ; 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 duration, and k2 is the aging attenuation coefficient.

[0007] In one embodiment, the model expression of the theoretical sag is: ; where is the theoretical sag, 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 duration, 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 cross section.

[0008] In one embodiment, the calculation method of the deviation rate is: ; When , it is determined that the sag is too large and the tension force is insufficient, and the controller controls the tensioning wheel to work to increase the tension force; When , it is determined that the sag is too small and the tension force is too large, and the controller controls the tensioning wheel to work to reduce the tension force; The The positive threshold is +5% to +10%, and the negative threshold is -5% to -10%.

[0009] In one embodiment, when the crawler speed v exceeds the speed threshold or the acceleration a exceeds the acceleration threshold, the set threshold of is temporarily adjusted to ±15%; When the crawler 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, and the default value is ±5% to ±10%.

[0010] In one embodiment, the temperature compensation coefficient k1 is obtained by fitting the test data of the elastic modulus of the rubber material at different temperatures; The aging attenuation coefficient k2 is obtained by fitting the historical statistical data of the cumulative usage duration of the crawler and the tensile permanent deformation amount.

[0011] In one embodiment, when t reaches the preset aging period, the controller automatically triggers the tension compensation program.

[0012] In one embodiment, the preset aging period is adjusted according to the material of the rubber crawler; If the material of the rubber crawler is natural rubber, the initial value of the preset aging period is 800 to 1200 hours; If the material of the rubber crawler is synthetic rubber, the initial value of the preset aging period is 500 to 800 hours.

[0013] In one embodiment, the excavator is also equipped with a timer, which is used to record the duration of the rubber crawler. This duration includes the effective working duration and the idle duration. Among them, the cumulative usage duration t only includes the effective working duration; The determination condition for the effective working duration is: the crawler speed v > 0.5 km / h and lasts for more than 5 minutes; The determination condition for the idle duration is: the crawler speed v ≤ 0.5 km / h and the duration does not exceed 5 minutes.

[0014] In one embodiment, when the idle duration exceeds 30 minutes, the sleep mode is automatically triggered. In the sleep mode, the timer pauses counting, and the tensioning wheel maintains the current tension force unchanged.

[0015] The advantages or beneficial effects in the above technical solutions at least include: 1. Temperature-sensitive dynamic compensation mechanism: The invention establishes a linear correlation model between the tension force and the ambient temperature by introducing a temperature compensation coefficient (k1). When the ambient temperature deviates from the reference value (such as 25 °C), the tension force is automatically adjusted: in a low-temperature environment, the tension force increases proportionally with the decrease in temperature to compensate for the relaxation trend caused by rubber hardening; in a high-temperature environment, the tension force decreases proportionally with the increase in temperature to avoid the overload risk caused by rubber softening. For example, in a low-temperature condition of -10 °C, the tension force can be automatically increased by 10% - 15% to ensure that the track sag remains within the safe threshold. Compared with the traditional fixed tension degree, the risk of low-temperature slipping is reduced by more than 60%.

[0016] 2. Quantitative tracking and compensation of aging attenuation: The invention realizes the dynamic management of the tension force throughout the life cycle of the track through an aging attenuation coefficient (k2) and a preset aging period (such as 800 - 1200 hours for natural rubber and 500 - 800 hours for synthetic rubber). The cumulative usage duration is used as a quantitative indicator of the aging degree. When the preset period is reached, the system automatically triggers the tension force compensation program to offset the influence of rubber elastic attenuation. For example, after the natural rubber track has been used for 1000 hours, the system can automatically increase the tension force by 5% - 8% to restore the track sag to the initial accuracy range. Compared with manual maintenance, the abnormal wear caused by aging is reduced by 40%, and the track life is extended by 15% - 20%.

[0017] 3. Closed-loop control of sag and multi-condition adaptability: The invention uses a displacement sensor to continuously collect the track sag (ΔL) of the slack section in real time and dynamically compare it with the theoretical sag (ΔLt), and realizes the closed-loop adjustment of the tension force based on the deviation rate formula (e). Under the default working condition, the system uses ±5% - ±10% as the deviation threshold to ensure that the tension accuracy reaches the millimeter level; when it is detected that the track speed or acceleration exceeds the threshold (such as v > 5 km / h or a > 0.5 m / s²), the threshold is automatically relaxed to ±15% to reduce the adjustment frequency under high-speed working conditions and improve the driving stability. Measured data shows that this mechanism reduces the adjustment frequency of the tension force under complex working conditions by 30% and saves about 10% of the equipment energy consumption.

[0018] 4. Material-differentiated adaptation and intelligent management: The invention provides material-specific parameter configurations according to the characteristic differences between natural rubber and synthetic rubber: natural rubber tracks use a lower temperature compensation coefficient (k1) and a longer aging period, while synthetic rubber uses higher temperature sensitivity parameters and a shorter aging period to ensure that optimal tension control effects can be obtained for tracks of different materials. At the same time, the system differentiates between the effective working duration (v > 0.5 km / h for ≥5 minutes continuously) and the idle duration to accurately count the cumulative usage duration, and triggers the sleep mode when the idle time exceeds 30 minutes, pausing the timing and maintaining the tension force.

[0019] 5. Improvement in Maintenance Efficiency and Safety: The invention records data such as temperature, duration, and sag amount in real time through a controller, establishes a track status trend analysis model, and can early warn of potential risks such as accelerated aging and sensor abnormalities (such as alarming when the measured value of k2 fluctuates by more than 20%), reducing the frequency of manual inspections by more than 30%. At the same time, the secondary tensioning mechanism effectively suppresses the risk of excessive sag amount, reducing the incidence of safety accidents such as track detachment and fracture by 80%, significantly improving the operation safety and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings illustrate exemplary embodiments of the present invention and, together with the description thereof, are used to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention and are included in this specification and form a part of this specification.

[0021] Figure 1 The installation position schematic diagram of the displacement sensor according to the embodiment of the present invention is shown; Figure 2 The schematic diagram of the excavator structure according to the embodiment of the present invention is shown.

[0022] Reference numerals: 1, fuselage; 11, displacement sensor; 111, inductor; 2, rubber track. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The embodiments of the present invention will be described in more detail below with reference to the drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. On the contrary, these embodiments are provided to more thoroughly and completely understand the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not used to limit the protection scope of the present invention.

[0024] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0025] A tensioning control method for a tensioning mechanism of a rubber track 2 of an excavator, the tensioning mechanism comprising: A controller for controlling the tensioning of the rubber track 2 by a tensioning wheel through a driving motor; A displacement sensor 11 installed on the fuselage 1 of the excavator, vertically aligned with the slack section of the rubber track 2, for detecting the actual sag amount of the rubber track 2 Specifically, the displacement sensor 11 is provided with a plurality of inductors 111 at the vertical height of the fuselage 1, such as Figure 1As shown, when the rubber crawler 2 is in front of the sensor 111, the sensor 111 senses that there is a rubber crawler 2 in front, and the sag of the rubber crawler 2 can be judged according to the position of the sensor 111 that senses the rubber crawler 2 in the height direction.

[0026] The control method includes: According to the material characteristics of the rubber crawler 2, a theoretical tension dynamic change model including a temperature compensation coefficient and an aging attenuation factor is established; the controller controls the tensioning wheel to tension the rubber crawler 2 according to the theoretical tension Ft, and reads the actual sag of the rubber crawler 2 detected by the displacement sensor 11 in real time ; and compare it with the theoretical sag to calculate the deviation rate between the two; If the deviation rate exceeds the threshold, the controller controls the tensioning wheel to perform secondary tensioning on the rubber crawler 2 until the actual sag tends to the theoretical sag within; Among them, the model expression is: ; where Ft is the theoretical tension, F0 is the reference tension; T is the real-time temperature, T0 is the reference temperature, k1 is the temperature influence coefficient; t is the cumulative usage duration, and k2 is the aging attenuation coefficient.

[0027] The temperature compensation coefficient k1 in the model expression is obtained by fitting the elastic modulus test data of the rubber material at different temperatures. Taking the material of the rubber crawler 2 as natural rubber and the reference temperature as 25°C as an example; as shown in Table 1: Table 1

[0028] Through linear regression, K1=-0.006 / °C is obtained; (when the temperature rises by 1°C, the tension decays by 0.6%) When the real-time temperature T = 40°C, Ft = F0×[1 + 0.008×(40 - 25)] = F0×1.12, that is, the tension increases by 12% compared with the reference value.

[0029] The aging attenuation coefficient k2 is obtained by fitting the historical statistical data of the cumulative usage duration of the crawler and the tensile permanent deformation amount: taking the natural rubber crawler 2 as an example; as shown in Table 2: Table 2

[0030] Through logarithmic regression, K2 = 0.0022 is obtained; (for every 1 hour of cumulative use, the tension decays by 0.22%); When t = 1200 hours, ; Furthermore, the above-mentioned theoretical sag ; where, is the theoretical sag, is the theoretical tension, T is the real-time temperature, T0 is the reference temperature, k1 is the temperature influence coefficient, t is the cumulative usage duration, k2 is the aging attenuation coefficient, L is the crawler span, E is the rubber elastic modulus, I is the moment of inertia of the cross-section. It should be noted that the crawler span, rubber elastic modulus, and moment of inertia of the cross-section need to be input into the controller in advance; After obtaining the theoretical sag , it is necessary to compare it with the actual sag measured by the displacement sensor 11, and calculate the deviation rate between the two: The calculation method of the deviation rate is: ; When , it is judged that the sag is too large and the tension is insufficient, and the controller controls the tensioning wheel to work to increase the tension; When , it is judged that the sag is too small and the tension is too large, and the controller controls the tensioning wheel to work to reduce the tension.

[0031] The positive threshold is +5% to +10%, and the negative threshold is -5% to -10%; (the example takes the median value of ±8%) In the following examples, it is set that the reference tension F0 = 60 kN, the crawler span L = 4 m, the elastic modulus E = 7 MPa, and the moment of inertia of the cross-section I = 0.006 m 4 .

[0032] Example calculation: I. Theoretical tensions in different scenarios: 1. Reference condition (T = 25 °C, t < 1000 hours): Ft = F0 = 60; 2. High-temperature scenario (T = 40 °C, t = 0 hours): Ft = 60 × [1 - 0.006 × (40 - 25)] × [1 - 0.0022 × ln(0 + 1)] = 60 × 0.91 × 1 = 54.6 kN; The tension decays by 9% at high temperature (due to the decrease in rubber elastic modulus); 3. Aging scenario (T = 25 °C, t = 1000 hours): Ft = 60 × [1 + 0] × [1 - 0.0022 × ln(1000 + 1)] ≈ 60 × 0.93 = 55.8 kN; After 1000 hours of cumulative use, the tension decays by 7% (due to rubber aging and deformation) 4. Combined influence of high temperature + aging: Condition: Ambient temperature T = 50 °C, cumulative usage duration t = 800 hours; Ft = 60 × [1 - 0.006 × (50 - 25)] × [1 - 0.0022 × ln(800 + 1)] ≈ 48.1 kN; Under certain extreme working conditions, there is also a protection mechanism. For example, when the ambient temperature T = 65 °C, which exceeds the normal working range, and the crawler load exceeds 120% of the rated value, the tension force is forced to F0 × 0.8 = 48 kN to reduce the crawler tensile stress and limit the crawler speed .

[0033] II. Theoretical sag Calculation: 1. Benchmark working condition (Ft = F0 = 60) ; 2. After temperature compensation (Ft = 54.6 kN): ; 3. After aging compensation (Ft = 55.8 kN): ; 4. Combined influence of high temperature + aging (Ft = 48.1 kN): ; III. Calculation of deviation rate e and tension adjustment: Measured: Actual sag = 2.2 mm, calculate ; ; Action: The controller drives the tensioning wheel through the drive motor to increase the tension force; Until: ; Measured: Actual sag = 1.6 mm, calculate ; ; Action: The controller drives the tensioning wheel through the drive motor to reduce the tension force; Until: ; And so on.

[0034] Based on the above, when the crawler speed v exceeds the speed threshold or the acceleration a exceeds the acceleration threshold, the set threshold is temporarily adjusted to ±15%; When the crawler 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, and the default value is ±5% - ±10%.

[0035] Based on the above further improvement, when t reaches the preset aging cycle, the controller automatically triggers the tension compensation program, where the preset aging cycle is adjusted according to the material of the rubber track 2; When the material of the rubber track 2 is natural rubber, the initial value of the preset aging cycle is 800 - 1200 hours; When the material of the rubber track 2 is synthetic rubber, the initial value of the preset aging cycle is 500 - 800 hours; The excavator is also equipped with a timer for recording the duration of the rubber track 2, which includes the effective working duration and the idle duration. Among them, the cumulative usage duration t only includes the effective working duration; the determination condition for the effective working duration is: the track speed v > 0.5 km / h and lasts for more than 5 minutes; the determination condition for the idle duration is: the track speed v ≤ 0.5 km / h and the duration does not exceed 5 minutes.

[0036] When the idle duration exceeds 30 minutes, the sleep mode is automatically triggered. In the sleep mode, the timer pauses counting, and the tensioning wheel maintains the current tension force unchanged.

[0037] After replacing the new natural rubber track, the controller executes: reset the cumulative duration t = 0, and the aging attenuation coefficient k2 is restored 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 / °C and aging cycle of 1000 hours.

[0038] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0039] Those skilled in the art should understand that the above embodiments are only for clearly explaining the present invention and not for limiting the scope of the present invention. For those skilled in the art, other changes or modifications can be made based on the above disclosure, and these changes or modifications are still within the scope of the present invention.

Claims

1. A tension control method for a tensioning mechanism of an excavator rubber track, characterized in that: The tensioning mechanism includes: A controller that controls the tensioning of the rubber crawler by driving a motor to control the tensioning wheel; A displacement sensor, installed on the body of an excavator and vertically aligned with the slack section of the rubber track, is used to detect the actual sag of the rubber track ; The control method includes: According to the material characteristics of the rubber track, a dynamic change model of the theoretical tension force Ft including the temperature compensation coefficient and the aging attenuation factor is established; the controller controls the tension of the rubber track by the tension pulley according to the theoretical tension force Ft, and reads the actual sag of the rubber track detected by the displacement sensor in real time ; and compare it with the theoretical sag to calculate the deviation rate between the two; If the deviation rate exceeds the threshold, the controller controls the idler to perform secondary tensioning on the rubber crawler until the actual sag tends to the theoretical sag inside; The model expression is as follows: ; where Ft is the theoretical tension, F0 is the reference tension; T is the real-time temperature, T0 is the reference temperature, k1 is the temperature influence coefficient; t is the cumulative usage duration, and k2 is the aging attenuation coefficient.

2. The tensioning control method of the rubber crawler tensioning mechanism of an excavator according to claim 1, characterized in that: The theoretical sag The model expression is: ； wherein, is the theoretical sag, is the theoretical tension, T is the real-time temperature, T0 is the reference temperature, k1 is the temperature influence coefficient, t is the cumulative usage duration, k2 is the aging attenuation coefficient, L is the crawler span, E is the rubber elastic modulus, and I is the cross-sectional moment of inertia.

3. The tensioning control method of the rubber crawler tensioning mechanism of an excavator according to claim 2, characterized in that: The calculation method of the deviation rate is as follows: ; When it is determined that the sag is too large and the tension is insufficient, the controller controls the tensioning pulley to work and increases the tension; When it is determined that the sag is too small and the tension is too large, the controller controls the tensioning pulley to work and reduces the tension; The positive threshold is +5% to +10%, and the negative threshold is -5% to -10%.

4. The tensioning control method of the rubber crawler tensioning mechanism of an excavator according to claim 3, characterized in that: When the crawler speed v exceeds the speed threshold or the acceleration a exceeds the acceleration threshold, the set threshold is temporarily adjusted to ±15%; When the crawler speed v is lower than or exceeds 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, and the default value is ±5% to ±10%.

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

6. The tension control method of the tensioning mechanism of the rubber crawler of the excavator according to claim 1, characterized in that: When t reaches the preset aging period, the controller automatically triggers the tension force compensation program.

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

8. The tension control method of the tensioning mechanism of the rubber crawler of the excavator according to claim 7, characterized in that: The excavator is also equipped with a timer for recording the duration of the rubber crawler. This duration includes the effective working duration and the idle duration. Among them, the cumulative use duration t only includes the effective working duration; The determination condition for the effective working duration is: the crawler speed v > 0.5 km / h and lasts for more than 5 minutes; The determination condition for the idle duration is: the crawler speed v ≤ 0.5 km / h and the duration does not exceed 5 minutes.

9. The tension control method of the tensioning mechanism of the rubber crawler of the excavator according to claim 8, characterized in that: When the idle duration exceeds 30 minutes, the sleep mode is automatically triggered. In the sleep mode, the timer pauses counting, and the tensioning wheel maintains the current tension force unchanged.

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