Chassis of pure-electric double-decker bus and stability calculation method therefor

Abstract

A chassis of a pure-electric double-decker bus and a stability calculation method therefor. The chassis of a pure-electric double-decker bus comprises an underframe (100), a front air suspension system (110), a middle air suspension system (120), a rear air suspension system (130), a front stabilization system (140), a middle stabilization system (150), and a rear stabilization system (160). By means of providing three stabilization systems, that is, the front stabilization system (140), the middle stabilization system (150) and the rear stabilization system (160), the stability of a bus during travelling is effectively improved; moreover, on the basis of a calculation formula for the roll angle of a bus body, it is derived that, when the roll stiffness C of the bus is greater, the roll angle φ of the bus body is smaller, that is, the travelling stability of the bus is better.

Description

A pure electric double-decker bus chassis and its stability calculation method Technical Field

[0001] The invention belongs to the technical field of buses and relates to a pure electric double-deck bus chassis and a stability calculation method thereof. Background Art

[0002] A bus refers to a means of transportation used to facilitate people's travel. It includes a chassis and a body arranged on the chassis. A pair of front wheels and a pair of rear wheels are arranged at the bottom of the chassis. When working, the bus travels on the ground via the front wheels and rear wheels. However, due to its large size, this type of bus will tip over or overturn when turning if its own chassis is not stable enough.

[0003] Summary of the Invention

[0004] The purpose of the present invention is to address the above-mentioned problems in the existing technology and to propose a pure electric double-decker bus chassis with high stability and a stability calculation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions: A pure electric double-decker bus chassis, comprising:

[0006] A chassis is provided with a front air suspension system, a center air suspension system and a rear air suspension system. The chassis is also provided with a front stabilization system corresponding to the front air suspension system, a center stabilization system corresponding to the center air suspension system and a rear stabilization system corresponding to the rear air suspension system.

[0007] In the above-mentioned pure electric double-decker bus chassis, the front air suspension system, the middle air suspension system and the rear air suspension system all include a frame connected to the chassis, and each of the frames is provided with at least two airbags.

[0008] In the above-mentioned pure electric double-decker bus chassis, the front stabilizing system, the middle stabilizing system and the rear stabilizing system all include stabilizing bars connected to the chassis, and each of the stabilizing bars is provided with two bushings.

[0009] A method for calculating the stability of a pure electric double-decker bus chassis, calculating the airbag roll stiffness C in the front air suspension system, the middle air suspension system, and the rear air suspension system a :

[0010] Where: C S —Airbag stiffness, N / mm;

[0011] L3—the distance between the left and right centers of the two airbags, mm;

[0012] In the above-mentioned method for calculating the stability of a pure electric double-decker bus chassis, the roll stiffness C of each stabilizer bar in the front stabilizer system, the middle stabilizer system and the rear stabilizer system is calculated. b :

[0013] Where: E—elastic modulus of the stabilizer bar material, E=2.1×10 5 MPa;

[0014] G—shear elastic modulus of the stabilizer bar material, G=8×10 4 MPa;

[0015] J—section moment of inertia of the stabilizer bar, J=πd 4 / 64, mm 4 ;

[0016] J p —Polar moment of inertia of the stabilizer bar, J p =πd 4 / 32, mm 4 ;

[0017] d—diameter of the stabilizer bar, in mm;

[0018] L c —The distance between the two end points of the stabilizer bar, in mm;

[0019] L0—the distance between the fixing points of the stabilizer bar, in mm;

[0020] L T —Stabilizer bar dimensions, in mm;

[0021] L1—Stabilizer bar size, in mm;

[0022] α—Rubber bushing stiffness loss percentage.

[0023] In the above-mentioned method for calculating the stability of a pure electric double-decker bus chassis, the above-mentioned L1 and L T : L1=LR L T =L C -2R

[0024] Where: L is the length of the stabilizer bar at both ends in the longitudinal direction, in mm;

[0025] R—bending radius of the stabilizer bar, in mm;

[0026] Lc—the distance between the two end points of the stabilizer bar, in mm;

[0027] In the above-mentioned method for calculating the stability of a pure electric double-decker bus chassis, the vehicle roll angle stiffness C is calculated as follows:

[0028] Where: C a1 —Airbag roll stiffness of the front air suspension system, N.mm / rad;

[0029] C b1 —Front lateral stabilizer bar roll stiffness, N.mm / rad;

[0030] C a2 —Roll angle stiffness of the airbag in the air suspension system, N.mm / rad;

[0031] C b2 —Roll angle stiffness of center stabilizer bar, N.mm / rad;

[0032] C a3 —Airbag roll stiffness of the rear air suspension system, N.mm / rad;

[0033] C b3 —Rear lateral stabilizer bar roll stiffness, N.mm / rad;

[0034] In the above-mentioned method for calculating the stability of a pure electric double-decker bus chassis, the roll angle φ of the vehicle body when turning is calculated based on the bus's sprung mass, bus center of mass height, vehicle roll stiffness, and lateral acceleration:

[0035] Where: m S —sprung mass of suspension, N;

[0036] a y —Rolling acceleration, m / s 2 ;

[0037] h s —Height of center of mass from the ground, mm;

[0038] In the above-mentioned method for calculating the stability of a pure electric double-decker bus chassis, the above-mentioned roll acceleration a is calculated. y :

[0039] Where: V—vehicle speed, m / s;

[0040] R v —Turn radius of the bus, mm.

[0041] In the above-mentioned method for calculating the stability of a pure electric double-decker bus chassis, the stability of the bus during driving is determined based on the roll angle of the bus.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] 1. In the present invention, by setting up three stabilization systems, namely the front stabilization system, the middle stabilization system and the rear stabilization system, the stability of the bus during driving is effectively improved.

[0044] 2. According to the calculation formula of the roll angle φ of the vehicle body roll, when the vehicle roll angle stiffness C is greater, the roll angle φ of the vehicle body roll is smaller, that is, it can be judged that the vehicle's driving stability is better.

[0045] 3. According to the stability calculation method of the pure electric double-decker bus chassis, appropriately increasing the distance between the two airbags in the same air suspension system and setting up the front stabilization system, the middle stabilization system and the rear stabilization system can effectively improve the stability of the bus during driving. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] FIG1 is a bottom view of the chassis of a pure electric double-decker bus.

[0047] FIG2 is a schematic structural diagram of a pure electric double-decker bus chassis in a preferred embodiment of the present invention.

[0048] FIG3 is a simplified structural diagram of a front air suspension system, a middle air suspension system, or a rear air suspension system.

[0049] FIG4 is a simplified structural diagram of a front stabilizing system, a middle stabilizing system, or a rear stabilizing system. DETAILED DESCRIPTION

[0050] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0051] As shown in Figures 1 to 4, a pure electric double-decker bus chassis of the present invention includes a chassis 100, a front air suspension system 110, a middle air suspension system 120, a rear air suspension system 130, a front stabilizing system 140, a middle stabilizing system 150 and a rear stabilizing system 160.

[0052] A front air suspension system 110, a center air suspension system 120 and a rear air suspension system 130 are provided on the chassis 100. The chassis 100 is also provided with a front stabilization system 140 corresponding to the front air suspension system 110, a center stabilization system 150 corresponding to the center air suspension system 120 and a rear stabilization system 160 corresponding to the rear air suspension system 130. Front wheels 170, center wheels 180 and rear wheels 190 are provided on the chassis 100, wherein the front air suspension system 110 and the front stabilization system 140 are arranged at the front wheels 170, the center air suspension system 120 and the center stabilization system 150 are arranged at the center wheels 180, and the rear air suspension system 130 and the rear stabilization system 160 are arranged at the center wheels 180. In the present invention, by providing three stabilization systems, namely the front stabilization system 140, the center stabilization system 150 and the rear stabilization system 160, the stability of the bus during driving is effectively improved.

[0053] The front air suspension system 110, the middle air suspension system 120 and the rear air suspension system 130 all include a frame 200 connected to the base frame 100, and each of the frames 200 is provided with at least two airbags 210. The front stabilization system 140, the middle stabilization system 150 and the rear stabilization system 160 all include a stabilizer bar 300 connected to the base frame 100, and each of the stabilizer bars 300 is provided with two bushings 310.

[0054] Based on the front air suspension system 110, the center air suspension system 120, the rear air suspension system 130, the front stabilization system 140, the center stabilization system 150, and the rear stabilization system 160 installed on the bus, the following formula is used to calculate the bus's roll angle φ to determine the bus's stability during driving:

[0055] The following is a method for calculating the stability of a pure electric double-decker bus chassis according to the present invention:

[0056] Step 1: Calculate the roll stiffness C of the airbag 210 in the front air suspension system 110, the middle air suspension system 120, and the rear air suspension system 130. a :

[0057] Where: C S —Airbag 210 stiffness, N / mm. This airbag is a standard part, so the stiffness of the airbag is known when purchasing it;

[0058] L3—center distance between two airbags 210, mm;

[0059] Furthermore, the roll stiffness C of the airbags 210 in the front air suspension system 110, the middle air suspension system 120, and the rear air suspension system 130 is a The calculation formula is the same.

[0060] According to the roll angle stiffness C of the airbag 210 a From the formula, we can know that under the condition that the width of the bus allows, the distance between the two airbags 210 can be appropriately increased to increase the roll angle stiffness C of the airbag 210. a .

[0061] Step 2: Calculate the roll stiffness C of each stabilizer bar 300 in the front stabilizer system 140 , the middle stabilizer system 150 , and the rear stabilizer system 160 . b : L1=LR L T =L C -2R

[0062] Wherein: L is the length of the two ends of the stabilizer bar 300 in the longitudinal direction, in mm;

[0063] R—bending radius of the stabilizer bar 300, in mm;

[0064] L c —The distance between the two end points of the stabilizer bar 300, in mm;

[0065] When L1 and L are calculated T Then, L1 and L T Substitute into the following stabilizer bar 300 roll angle stiffness C b in the calculation formula.

[0066] Where: E is the elastic modulus of the material of the stabilizer bar 300, E = 2.1 × 10 5 MPa;

[0067] G--Shear elastic modulus of the stabilizer bar 300 material, G=8×10 4 MPa;

[0068] J—sectional moment of inertia of the stabilizer bar 300, J=πd 4 / 64, mm 4 ;

[0069] J p —Polar moment of inertia of the stabilizer bar 300, J p =πd4 / 32, mm 4 ;

[0070] d—diameter of the stabilizer bar 300, in mm;

[0071] L c —The distance between the two end points of the stabilizer bar 300, in mm;

[0072] L0—the distance between the fixed points of the stabilizer bar 300, in mm;

[0073] L T —Dimensions of stabilizer bar 300, in mm;

[0074] L1—Stabilizer bar 300 size, in mm;

[0075] α—Rubber bushing 310 stiffness loss percentage;

[0076] Furthermore, the roll angle stiffness C of the stabilizer bar 300 in the front stabilizer system 140 , the middle stabilizer system 150 , and the rear stabilizer system 160 is b The calculation formulas are the same; the value of α is obtained by experimental measurement.

[0077] Step 3: Calculate the roll angle stiffness C of the airbag 210 of the front air suspension system 110 according to the formula in step 1. a1 , the roll stiffness C of the airbag 210 of the air suspension system 120 a2 and the roll stiffness C of the airbag 210 in the rear air suspension system 130 a3 , and then calculate the roll angle stiffness C of the stabilizer bar 300 of the front stabilizer system 140 using the formula in step 2 b1 , the roll stiffness C of the stabilizer bar 300 of the central stabilization system 150 b2 and the roll stiffness C of the stabilizer bar 300 in the rear stabilization system 160 b3 , calculate the vehicle roll stiffness C:

[0078] Where: C a1 —Roll angle stiffness of the airbag 210 of the front air suspension system 110, N.mm / rad;

[0079] C b1 —Roll angle stiffness of front stabilizer bar 300, N.mm / rad;

[0080] C a2 —Roll stiffness of the airbag 210 of the air suspension system 120, N.mm / rad;

[0081] C b2 —Roll angle stiffness of center stabilizer bar 300, N.mm / rad;

[0082] C a3 —Roll angle stiffness of the airbag 210 of the rear air suspension system 130, N.mm / rad;

[0083] C b3 —Roll angle stiffness of rear stabilizer bar 300, N.mm / rad;

[0084] Step 3: Calculate the roll angle φ of the vehicle when turning based on the sprung mass, center of mass height, roll stiffness, and lateral acceleration of the vehicle:

[0085] Changing the formula in step 3, we get:

[0086] Where: m S —sprung mass of suspension, N;

[0087] a y —Rolling acceleration, m / s 2 ;

[0088] h s —Height of center of mass from the ground, mm;

[0089] g—weight acceleration, m / s 2 ;

[0090] Furthermore, the suspension sprung mass m S It refers to the sprung mass of all airbags 210 in the bus, which can be obtained by accumulating the number of airbags actually installed in the bus; the height of the center of mass from the ground h s It refers to the height of the center of the bus from the ground. The center of the bus refers to the center of the combination of the bus body and the bus chassis 100, which can be obtained by measurement.

[0091] The above-mentioned roll acceleration a y The calculation formula is:

[0092] Where: V—vehicle speed, m / s, this data can be obtained from the speed sensor on the vehicle;

[0093] R v —The turning radius of the bus, mm, which can be obtained through measurement.

[0094] In summary, according to the calculation formula of the roll angle φ of the vehicle body roll, it can be concluded that when the vehicle roll angle stiffness C is greater, the roll angle φ of the vehicle body roll is smaller, that is, it can be judged that the driving stability of the vehicle is better.

[0095] Furthermore, by appropriately increasing the distance between the two airbags 210 and installing the front stabilization system 140 , the middle stabilization system 150 and the rear stabilization system 160 , the stability of the bus during driving can be effectively improved.

[0096] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0097] In addition, in the present invention, descriptions such as "first," "second," and "one" are for descriptive purposes only and should not be understood to indicate or imply their relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0098] In the present invention, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0099] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

Claims

1. A pure electric double - decker bus chassis, Characterized in that, Comprising: A chassis frame, on which a front air suspension system, a middle air suspension system and a rear air suspension system are provided. On the chassis frame, a front stability system corresponding to the front air suspension system, a middle stability system corresponding to the middle air suspension system and a rear stability system corresponding to the rear air suspension system are also provided.

2. A pure electric double - decker bus chassis according to claim 1, Characterized in that, The front air suspension system, the middle air suspension system and the rear air suspension system all include a frame body connected to the chassis frame, and at least two air bags are provided on each frame body.

3. A pure electric double - decker bus chassis according to claim 2, Characterized in that, The front stability system, the middle stability system and the rear stability system all include a stabilizer bar connected to the chassis frame, and two bushings are provided on each stabilizer bar.

4. A method for calculating the stability of a pure electric double - decker bus chassis according to any one of claims 1 to 3, Characterized in that, Calculate the airbag roll stiffness C in the front air suspension system, the middle air suspension system, and the rear air suspension system a : Where: C S — airbag stiffness, N / mm; L 3 — Center distance between the left and right airbags, mm; 5. A method for calculating the stability of a pure electric double - decker bus chassis according to claim 4, Characterized in that, Calculate the roll stiffness C of each stabilizer bar in the front-stabilized system, middle-stabilized system, and rear-stabilized system b : Where: E—the elastic modulus of the stabilizer bar material, E = 2.1×10 5 MPa; G—Shear elastic modulus of the stabilizer bar material, G = 8×10 4 MPa; J—Section moment of inertia of the stabilizer bar, J = πd 4 / 64, mm 4 ; J p — Polar moment of inertia of the stabilizer bar cross-section, J p = πd 4 / 32, mm 4 ; d—the diameter of the stabilizer bar, unit: mm; L c — The distance between the two end points of the stabilizer bar, in mm; L 0 — Distance between stabilizer bar fixing points, in mm; L T — The stabilizer bar dimension, in mm; L 1 — Dimension of the stabilizer bar, in mm; α—the percentage of stiffness loss of the rubber bushing.

6. A method for calculating the stability of a pure electric double - decker bus chassis according to claim 5, Characterized in that, Calculate the above-mentioned L 1 and L T : L 1 = L - RL T = L C - 2R Wherein: L—the length of both ends of the stabilizer bar in the longitudinal direction, unit: mm; R—the bending radius of the stabilizer bar, unit: mm; L c — The distance between the two end points of the stabilizer bar, in mm; 7. A method for calculating the stability of a pure electric double - decker bus chassis according to claim 5, Characterized in that, Calculate the vehicle roll stiffness C: Where: C a1 — The roll stiffness of the airbag of the front air suspension system, N·mm / rad; C b1 — Lateral inclination stiffness of the front anti-roll bar, N·mm / rad; C a2 — The roll stiffness of the airbag of the central air suspension system, N·mm / rad; C b2 — Lateral inclination stiffness of the anti-roll bar on the C side, N.mm / rad; C a3 — Airbag roll stiffness of the rear air suspension system, N.mm / rad; C b3 — Lateral roll stiffness of rear anti-roll bar, N.mm / rad; 8. A method for calculating the stability of a pure electric double - decker bus chassis according to claim 7, Characterized in that, According to the sprung mass of the passenger car, the height of the vehicle's center of mass, the roll stiffness of the vehicle, and the lateral acceleration, calculate the roll angle φ of the vehicle body roll when the vehicle is turning: where: m S — sprung mass of the suspension, N; a y — Lateral acceleration, m / s 2 ; h s — Height from the centroid to the ground, mm; 9. A method for calculating the stability of a pure electric double - decker bus chassis according to claim 8, Characterized in that, Calculate the roll acceleration a described above y : Wherein: V—the vehicle speed, m / s; R v — Turning radius of the passenger car, mm.

10. A method for calculating the stability of a pure electric double - decker bus chassis according to claim 8, Characterized in that, Judge the stability of the bus during driving according to the roll angle φ of the bus.

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