CN101814099A

CN101814099A - Analysis and calculation method of internal resistance and power consumption of crawler attachment

Info

Publication number: CN101814099A
Application number: CN200910021225A
Authority: CN
Inventors: 朱爱斌; 王步康; 杨涛仁; 宿月文; 张莉娟
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-02-23
Filing date: 2009-02-23
Publication date: 2010-08-25

Abstract

The invention relates to an analysis and calculation method of internal resistance and power consumption of a crawler attachment. The specific analysis content comprises: (1) external characteristic theory analysis comprising the analysis of unit pressure of ground, sinking depth, ground traction and driving resistance; (2) internal frictional resistance theoretical derivation analysis comprising the analysis of frictional resistance generated by the relative rotation of a track pin and a pin bush, frictional resistance between a truck frame and a caterpillar band, frictional resistance at the position of a driving wheel bearing, frictional resistance at the position of a guide pulley wheel bearing and meshing frictional resistance of a driving bearing and a track shoe; and (3) the determination of driving torque and power comprising the determination of mechanical equilibrium theory and driving torque, and the determination of power balance theory and driving power. On the basis of solid theoretical research, the invention analyzes and calculates the internal resistance and power consumption of the crawler attachment and provides favourable reference for crawler attachment design; and the software of the invention has convenient and quick pretreatment and posttreatment.

Description

Method for analyzing and calculating internal resistance and power consumption of crawler travelling mechanism

Technical Field

The invention relates to analysis and calculation of internal resistance and power consumption, in particular to analysis and calculation of internal resistance and power consumption of a crawler walking mechanism.

Background

The tracked vehicle is a self-paving road vehicle, and plays an important role in the fields of modern military, agriculture, energy, buildings and the like due to the strong traction and adhesion capability, adaptability to severe ground environments and good passing performance. Crawler track is an important component of a tracked vehicle. The walking device is stronger in road surface adaptability than a wheel type walking mechanism. The crawler traveling mechanism can travel on the road surface in which the wheel type device cannot travel, such as environments of deep snow, marsh, soft mud, sand and stone, and the like, the ground pressure of the crawler traveling mechanism is far less than that of the wheel type device, and the borne load impact is also greater than that of the wheel type device. Therefore, the crawler-type travelling mechanism can exert greater advantages for heavy engineering machinery such as coal mining machines, excavators and the like which often work in sand and soft mud on mines and are simultaneously impacted by large loads in the working process.

However, crawler tracks have been very deficient to date. When the vehicle runs on a road, the mechanical efficiency of the vehicle is far lower than that of a wheel type running device; crawler tracks are far less reliable than wheel-type units and add significant complexity and cost to the vehicle system. The lubrication conditions are poor because they typically operate in harsh ground environments. The phenomenon of friction and abrasion is very common and is a main reason for the failure and the influence on the service life of the engineering machinery. Therefore, the method has great economic significance for deeply researching various friction laws in the engineering machinery crawler travel mechanism, analyzing the generation mechanism of the various friction laws, seeking a reasonable solution, realizing energy conservation and consumption reduction, improving reliability and prolonging service life.

In addition, the crawler belt walking mechanism is a very complex mechanical system, and people have difficulty in deeply and comprehensively knowing the maneuvering performance of the crawler belt walking mechanism. For a long time, the research on the tracked vehicle is always on the basis of experience and test, a large number of experience formulas are required to be established, a large number of experimental data are counted, the research period is long, quantitative identification and drawing are difficult to achieve on a plurality of factors influencing the performance of the tracked vehicle, and the design-trial production-test-improvement is always the traditional mode of the research on the tracked vehicle. The disadvantages of this mode are evident. The design depending on experience needs a large amount of manpower and material resources, and the design itself is inaccurate, which causes waste of design resources to a certain extent, and needs guidance of scientific theory and quantitative analysis and calculation. Therefore, the system analyzes and calculates the internal resistance and the power consumption of the crawler travel mechanism, and has guiding significance for deeply researching various friction rules in the crawler travel mechanism; the development of analysis and calculation software for the internal resistance and the power consumption of the crawler system is of great significance for shortening the calculation time and improving the efficiency.

Disclosure of Invention

The invention aims to provide a theoretical analysis and calculation method for the internal resistance and the power consumption of a crawler travel mechanism, which is convenient and quick due to the fact that calculation software is provided, is greatly convenient for a user to analyze and calculate the internal resistance and the power consumption of the crawler travel mechanism, avoids the requirement that the designer needs to have professional knowledge to analyze, and can analyze and calculate directly through simple interface operation.

The main research method comprises the following steps:

the system analyzes the theory of the external characteristics, the internal friction resistance, the driving torque and the power of the crawler traveling mechanism, considers the influence factors of the crawler machine and soil, and comprehensively provides the mechanical analysis and calculation of the crawler system from the aspects of the ground pressure ratio, the sinking depth, the ground traction force, the running resistance, the friction resistance generated by the relative rotation of the crawler pin and the pin bush, the friction resistance between the crawler frame and the crawler, the friction resistance at the driving wheel bearing, the friction resistance at the guide wheel bearing, the meshing friction resistance between the driving gear teeth and the crawler plate, and the like.

1. Theoretical derivation analysis of external characteristics

(1) Ground pressure analysis

The ground contact pressure of the track is an important parameter of the track-type machine, which directly determines the running characteristics of the machine and is closely related to the position of the center of gravity of the vehicle (i.e., the eccentricity of the center of gravity with respect to the geometric center of the ground contact area of the track). According to the ground mechanics theory, the longitudinal eccentricity e is considered. When the longitudinal eccentricity is within e ∈ (0, L/6), the grounding pressure is distributed in a trapezoidal mode; when e epsilon (L/6, L/2), the grounding pressure diagram is distributed in a right triangle with a reduced base, as shown in FIG. 1. When e belongs to (L/6, L/2), the calculation formula of the specific grounding pressure is as follows:

P_min＝0

P_{\max} = \frac{2 G}{3 b (L - 2 e)}

P_{x} = \frac{G}{9 b {(L / 2 - e)}^{2}} (L - 3 e + x)

wherein, P_minIs the minimum ground specific pressure, P_maxIs the maximum ground specific pressure, P_xIs the ground pressure at any position of the ground section.

(2) Analysis of depth of subsidence

The ground pressure of the crawler belt causes the soil to sink downwards, and the calculation formula is as follows:

wherein P is the ground pressure, kpa; k_CIs the deformation modulus, kN/m, determined by the viscous constituents of the soilⁿ⁺¹；

Is the deformation modulus determined by the soil friction component, kN/mⁿ⁺²(ii) a b is the track width, m; n is a soil deformation index; z is the depth of subsidence, m.

(3) Ground tractive effort analysis

The ground traction distribution is shown in fig. 2.

When the eccentricity is located at (0, L/6):

the grounding pressure equation is:

then

The shear strength of the soil is as follows:

the shear stress strain equation is:

the ground traction equation is:

② when the eccentricity is located at (L/6, L/2):

the ground pressure distribution equation is as follows:

and formula of shear stress

Obtaining the ground traction force equation of F_H＝∫_Aτ dA, that is,

analysis of running resistance

The running resistance of a crawler-type construction machine is also referred to as external resistance. The invention only considers the condition of uniform walking of the horizontal straight line and has low vehicle speed, thus not considering wind resistance, gradient resistance and acceleration resistance. The external resistance is only the deformation resistance caused by the ground soil being squeezed by the crawler. The driving resistance diagram is shown in fig. 3.

When e belongs to [0, L/6], the running resistance calculation formula is as follows:

when e is equal to (L/6, L/2), the calculation formula of the running resistance is

2. Theoretical derivation analysis of internal friction resistance

The internal resistance of the crawler is mainly composed of the friction force of a driving wheel and a guide wheel bearing, the contact friction force of a crawler frame and a crawler track chain, the friction force of a pin and a pin sleeve when the crawler is wound, and the engagement friction force of driving gear teeth and the crawler. According to the mechanical balance condition of the whole vehicle, the tension of the track is the thrust of the ground to the vehicle, and the thrust is equal to the running resistance.

(1) Analysis of frictional resistance generated by relative rotation of track pin and pin sleeve

As shown in FIG. 4, each shoe must be rotated by an angle α under the action of the wrap as it passes point A, B, C, D, and

z is the number of drive wheel teeth. Assuming that M is the friction torque, the friction work of rotating by an angle alpha is

The friction work of the driving wheel rotating for one circle is

Suppose that the traction force required to overcome this friction is F_r1And is and

wherein P is track tension; d is the pin diameter; μ is the coefficient of friction; z is the number of drive gear teeth; t is the track shoe pitch;

when the vehicle moves forward, the point A is the tension of the tight side and is set as P₁B, C, D three points are the tension of the loose edge, set as P₂. Therefore, the frictional resistance during the forward movement is

(2) Analysis of frictional resistance between track frame and track

As shown in fig. 5, the track frame is embedded in the track of the track to form sliding friction, and the friction between the track frame and the track is obtained by a sliding friction calculation formula as follows: f_r2＝μG

(3) Analysis of frictional resistance at drive wheel bearing

Because the bearings adopted by the crawler travel mechanism are rolling bearings, a formula is calculated according to the friction torque of the rolling bearings:

wherein, M: frictional torque

μ: coefficient of friction

P: bearing load

d': nominal bore of bearing

The bearing load calculation formula is P ═ f_p×F_rIn which F is_rIs the radial load, f_pIs the load factor (for medium impact, typically 1.2-1.8). The radial load of the bearing is the horizontal radial support reaction force F of the bearing_HRadial support reaction force F with vertical plane_VThe vector sum of (1). Track tight side tension F_K. When advancing, as shown in FIG. 6, the radial load

Because G' and F₀，F_KIs relatively small and can be ignored, so

The upper limit of the load factor is 1.8, and P is 1.8F_r。

When advancing, approximately consider

Then

(4) Analysis of frictional resistance at guide wheel bearing

When the crawler belt walking mechanism advances, the stress is as shown in figure 7, and the radial load isBut instead of the other end of the tube

Approximately consider that

The upper limit of the load coefficient is 1.8, and then P is 1.8F_r. Then:

when moving forward, the friction torque is

(5) Analysis of meshing frictional resistance between drive gear teeth and track shoe

As can be seen in FIG. 8, the contact normal force is

Contact friction force F_R＝μ*F_NThe component of the contact friction force in the traction direction is F_RE＝F_Rsinα_ωCombining the above three formulas to obtain the engagement frictional resistance of the driving wheel and the track pin, F_RE＝μgtanα_ωF_T(ii) a And assuming that only the last 1/4 entered friction as the track pin moved in the bottom slot, therefore

Wherein,

an inter-tooth division angle; z_TNumber of drive gear teeth; the frictional resistance of engagement of the drive wheel and the track pin can thus again be written:

thus, the frictional resistance of engagement between the drive wheel and the track pin is calculated, which can be further summarized as calculation F_T。F_TIt can be seen as the sum of the track pretension and the additional tension caused by the drive wheel, i.e. F_T＝2*F₀+F_K。

Then:

3. determination of drive torque and power

(1) Determination of the mechanical equilibrium theory and the drive torque

As can be seen from fig. 9, when the entire vehicle is considered as a study subject based on the force balance relationship, Σ F — F is obtained_KWhere, Σ F is the sum of the external resistances; f_KIs a tangential traction. If the track system is considered separately, then:

\frac{M_{K} - M_{r}}{r_{K}} = F_{K}

wherein M is_rThe equivalent internal friction resistance torque is caused by friction generated by relative rotation of the track pin and the pin bushing, friction between the track frame and the track, friction at a bearing of the driving wheel, friction at a bearing of the guide wheel and meshing friction of the driving gear teeth and the track shoe. The above formula can be changed into

\frac{M_{K}}{r_{K}} - \frac{M_{r}}{r_{K}} = F_{K}

Let F_rFor equivalent resistance, then the above equation can be changed to

\frac{M_{K}}{r_{K}} = F_{r} = F_{K}

From the analytical calculation, F is known_rIs composed of five items, i.e.

From the above formula, one can obtain:

F_{K} = \frac{M_{K}}{r_{K}} - F_{r} = \frac{M_{K}}{r_{K}} - (F_{r 1} + F_{r 2} + F_{r 3} + F_{r 4} + F_{r 5})

according to the force balance relationship, the external running resistance is equal to the ground traction, so that in the case of a horizontal constant speed and a low speed, the external resistance of a single track is expressed as:

thus, the equation is obtained:

the drive torque M of the drive wheel is obtained_K。

Setting a gear ratio from the motor to the drive wheels to be i_mTransmission efficiency is eta_mThen the motor torque is equal to

(2) Determination of power balance theory and driving power

The traction power balance indicates the distribution, consumption and utilization of the tangential traction force and the effective power of the motor when the machine works. Power P of motor_eFirstly, the loss P of the transmission mechanism is overcome_cInternal loss

And external resistance loss P_rThe rest of which is the effective output work P_kp. Therefore, the power of the motor must satisfy the condition

<math><mrow><msub><mi>P</mi><mi>kp</mi></msub><mo>=</mo><msub><mi>P</mi><mi>e</mi></msub><mo>-</mo><msub><mi>P</mi><mi>c</mi></msub><mo>-</mo><munderover><mi>Σ</mi><mrow><mi>i</mi><mo>=</mo><mn>1</mn></mrow><mn>5</mn></munderover><msub><mi>P</mi><mi>i</mi></msub><mo>-</mo><msub><mi>P</mi><mi>r</mi></msub><mo>&GreaterEqual;</mo><mn>0</mn></mrow></math>

Assuming that the design vehicle speed (actual vehicle speed) is V and the slip ratio is i, the linear speed of the sprocket (theoretical vehicle speed) is

According to the analysis, the information is obtained,

is composed of five parts, and is calculated as follows:

friction power loss of pin and pin bush: f_r1V_TAmong them is the linear velocity of the chain wheel

The friction power consumption between the crawler frame and the crawler is as follows: f_r2V_TIn which V is_TIs the linear velocity of the chain wheel

Driving wheel bearing's friction consumption:

friction power consumption of the guide wheel bearing:

driving gear tooth engagement friction power consumption:

once engaged, the friction work is Q ═ F_r5s, s are the rubbing distances. The driving wheel rotates one circle and is meshed for 10 times, and the total work is 10Q. The time taken for one rotation of the driving wheel is T, because

V_T＝r_Kω, then the engagement power consumption can be expressed as

External power loss: power loss due to running resistance

Drawings

FIG. 1 ground pressure distribution

FIG. 2 floor adhesion distribution

FIG. 3 schematic diagram of the running resistance

FIG. 4 pin and pin sleeve force diagram

FIG. 5 track frame and track contact position

Figure 6 drive wheel bearing diagram during forward travel

Figure 7 guide wheel bearing diagram during forward travel

FIG. 8 engagement diagram of drive gear teeth and track plate holes

FIG. 9(a) complete machine force diagram (b) track tension distribution

Detailed Description

A preferred set of data for the present invention is as follows:

the extrinsic characteristic calculation parameters are: g is 480kN, b is 0.6m, L is 2m, and the longitudinal eccentricity e is 0.6 m;

the internal frictional resistance calculation parameters are as follows: t is 0.15m, z is 10, d is 0.025 m;

the power calculation is carried out on the premise that the eccentricity is 0.6m and the linear speed of the chain wheel is 15 m/min.

Substituting the parameters into the corresponding calculation formula can obtain the following results:

output variable	Outputting the data	Unit of
output variable	Outputting the data	Unit of	Maximum ground specific pressure	666.6667	kPa
Depth of subsidence	0.0651	m	Maximum ground specific pressure	666.6667	kPa

Output variable	Outputting the data	Unit of
Output variable	Outputting the data	Unit of	Running resistance	43.3863	kN
Maximum adhesion to the ground	253.5623	kN	Running resistance	43.3863	kN
Maximum adhesion to the ground	253.5623	kN	Driving force during straight advance	102.7412	kN
Frictional resistance between pin and pin bush during straight advance	3.1218	kN	Driving force during straight advance	102.7412	kN
	3.1218	kN	Frictional resistance between track frame and track when advancing straight	72.0000	kN
Frictional resistance torque at the bearing of the driving wheel during linear advance	0.0636	kN.m		72.0000	kN
	0.0636	kN.m	Frictional resistance torque at guide wheel bearing during straight advance	0.0143	kN.m
Frictional resistance of engaging track shoe with driving gear teeth during straight advance	7.1625	kN		0.0143	kN.m
	7.1625	kN	Friction power consumption of pin and pin sleeve during straight advance	0.7763	kW
Friction power consumption of crawler frame and crawler track during straight advance	18.0000	kW		0.7763	kW
	18.0000	kW	Friction power consumption of driving wheel bearing when straight going forward	0.0662	kW
Friction power consumption of guide wheel bearing during straight advance	0.0149	kW		0.0662	kW
	0.0149	kW	Engaged friction power consumption of track shoe and driving gear teeth during straight advance	0.8668	kW
Motor drive torque	161.1626	N.m		0.8668	kW
Motor drive torque	161.1626	N.m	Power consumption by external driving resistance	4.6098	kW
Minimum power of motor	28.6284	kW	Power consumption by external driving resistance	4.6098	kW

Claims

1. The method for analyzing and calculating the internal resistance and the power consumption of the crawler traveling mechanism is characterized by comprising the following specific analysis contents:

(1) theoretical derivation analysis of external characteristics:

analyzing the grounding specific pressure: according to the ground mechanics theory, the longitudinal eccentricity e is considered, and when the longitudinal eccentricity is e ∈ (0, L/6), the grounding pressure is distributed in a trapezoidal mode; when e epsilon (L/6, L/2), the grounding pressure diagram is in a right-angled triangle with a reduced base.

When e belongs to (L/6, L/2), the calculation formula of the track grounding pressure is as follows:

P_min＝0

P_{\max} = \frac{2 G}{3 b (L - 2 e)}

P_{x} = \frac{G}{9 b {(L / 2 - e)}^{2}} (L - 3 e + x)

analyzing the depth of subsidence: the ground pressure of the crawler belt causes the soil to sink downwards, and the calculation formula is as follows:

analyzing ground traction force:

when the eccentricity is at (0, L/6), the ground traction equation is:

when the eccentricity is at (L/6, L/2), the ground tractive effort equation is:

analysis of running resistance:

when the longitudinal eccentricity is located in e epsilon [0, L/6], the running resistance calculation formula is as follows:

when the longitudinal eccentricity is located at e (L/6, L/2), the running resistance is calculated by the formula:

(2) theoretical derivation and analysis of internal friction resistance:

analyzing the friction resistance generated by the relative rotation of the track pin and the pin sleeve:

the traction required to overcome this friction is:

analyzing the friction resistance between the crawler frame and the crawler:

the friction between the track frame and the track is as follows: f_r2＝μG

Analysis of frictional resistance at the bearing of the driving wheel:

the friction torque at the driving torque bearing is:

fourthly, analyzing the frictional resistance of the guide wheel bearing:

the friction torque at the guide wheel bearing is: m_r4＝d′μf_rF₀

Analyzing the engagement friction resistance of the driving gear teeth and the track shoe:

the meshing friction resistance of the driving wheel and the track pin is as follows:

(3) determination of drive torque and power:

determination of mechanical balance theory and driving torque:

determination formula of driving torque of driving wheel:

determining a power balance theory and driving power:

theory of power balance:

the internal power loss consists of five parts: a) frictional power loss F of pin and pin bush_r1V_T(ii) a b) Friction power consumption between the track frame and the track: f_r2V_T(ii) a c) Friction power consumption of the drive wheel bearing:d) friction power consumption of the guide wheel bearing:

e) drive gear tooth engagement friction power consumption:

external power loss:

2. the method for analyzing and calculating the internal resistance and the power consumption of the crawler unit according to claim 1, wherein the specific calculation program of the functional module of the internal resistance and power consumption analysis software is as follows:

(1) a data module:

including soil parameter data and coefficient of friction data. The soil parameter data mainly stores the deformation modulus K determined by soil characteristic parameters commonly used in a crawler system, such as the deformation index n of soil and the soil viscosity component_CDeformation modulus determined by soil friction component

Etc. records of the same; the coefficient of friction provides a range of values for the coefficient of friction of different materials,

(2) a calculation module:

external characteristic calculations and internal frictional resistance and power consumption calculations. The external characteristic calculation mainly comprises four external characteristics of ground pressure, sinking depth, ground traction and straight-line running resistance of the crawler belt walking system; the internal friction resistance and power consumption calculation part mainly comprises five parts, namely friction resistance and power consumption generated by relative rotation of the track pin and the pin bush, friction resistance and power consumption between the track frame and the track, friction resistance and power consumption at the bearing of the driving wheel, friction resistance and power consumption at the bearing of the guide wheel, and friction resistance and power consumption generated by kneading the driving gear teeth and the track plate, and can calculate the values of the friction resistance and the power consumption of five parts mainly generating the friction power consumption in the track system; the calculation is divided into two cases of single calculation and multiple calculations. A single calculation is to find the specific value of the target variable in that case for a set of design data. The multiple calculations can be carried out by selecting the parameter variables, setting the maximum and minimum values of the parameter variables and the change step length to obtain a group of values of the target variable in the process of changing along with the parameter variables,

(3) a statistical report module:

and returning the statistical distribution graph of the power consumption of each part in the form of a pie chart and a histogram.