RU167299U1 - FRAME BODY BODY TYPE MONOK - Google Patents

Abstract

A monocoque type bus body frame comprising a front, left and right sidewalls, a base, a roof, a rear and transverse partitions of a passenger compartment, characterized in that all of the listed components are made in the form of reinforced panels and together form a closed structure of the body frame designed in such a way that when this structure is loaded with a torsional load, the individual rods of this structure experience a mainly tensile or compressive load, but not flexural, and the skin and panels experience a shear load in and x plane.

Description

The technical solution relates to the automotive industry, in particular, to the body structure of the bus.

From the existing level of technology, a closed-type bus body frame is described in the book by Y. Pavlovsky. Automobile bodies - Moscow: Mashinostroyenie, 1977, p. 341, including a base, a front, a back, a left and a right side wall and a roof, consisting of longitudinal, transverse or vertical beams (side members, cross members, uprights and arcs), rigidly interconnected and reinforced with thin-walled skins over the entire body area, except for openings of windows, doors and hatches (traditional scheme). The disadvantage of this design is the high loading of window and door racks by bending during operation of the bus, as well as the relatively low bending and torsional stiffness of the body as a whole.

The closest to the claimed technical solution is the bus body frame described in the patent for utility model No. 39562 "Bus body frame" published on 08/10/2004 (IPC B62D 21/02, B62D 25/02, B62D 31/02, author and applicant Peskov V.I., RU), consisting of left and right side frames, roof and front and rear frames made of thin-walled metal power elements of rectangular cross section so that a system of longitudinal, transverse and diagonal connections in the form of rigid triangles is created (triangular diagram ), including in the area of the window openings of the left and right side frames and window openings tailgate. This design can be considered as a prototype.

The design of the prototype has several disadvantages.

1. The openings of the front window of the front end of the prototype are formed by vertical and horizontal power elements (according to the traditional scheme), which is justified by the need to ensure regulated visibility from the driver's seat, therefore they have low shear stiffness in the front plane compared to other parts of the structure made in a triangular pattern. This reduces the stiffness of the front of the body during emergency side rollover. It also reduces the torsional stiffness of the body as a whole and leads to the appearance of increased stresses in the racks of the windshield when they are bent locally in the twisting mode of the body.

2. The body frame design described in the patent of the prototype does not have a developed window-sill section, which makes it almost impossible to organize doorways in the side walls of the body without violating the mechanics of their strength work in a triangular pattern. For doorways, as in the case of frontal window openings, there is a return to the traditional frame organization scheme. This leads to a decrease in body stiffness as a whole in bending and twisting modes. Also, there are increased stresses in the door pillars during their local bending at the indicated loading modes of the body.

3. The prototype patent does not say anything about the body base frame. Apparently, its organization is implied according to the traditional scheme, which entails all the indicated disadvantages of this scheme.

The task at hand is to improve the design of the bus body.

The technical result is an increase in shear stiffness of individual parts of the frame and bending and torsional rigidity of the body frame assembly, as well as increased passive safety of the bus body.

This technical result is achieved in that the monocoque type bus body frame containing the front, left and right sidewalls, the base, the roof, the rear and the transverse partitions of the passenger compartment are made in the form of bridge trusses of the bridge type, sometimes reinforced by sheet sheathing, or in the form of load-bearing multilayer panels , or as a combination of these structures, i.e. in the form of reinforced panels, together form a closed structure of the body frame, designed in such a way that when this structure is loaded with a torsional load, the individual rods of this structure undergo a tensile or compressive load, but not bending, and the skin and panels experience a shear load in their plane .

The proposed design is shown in the figure - a general view.

The monocoque bus body frame contains the following main structural parts: left 1 and right 2 sidewalls, front 3, rear 4, roof 5, base 6, including wheel niches 7, one or more transverse partitions of the passenger compartment 8 may also be present. Sidewalls 1, 2 necessarily have developed window sections 9, which allows you to organize doorways in them without violating the desired mechanics of strength work. The main listed structural parts of the carcass are made in the form of rod trusses of the bridge type, possibly supported by sheet sheathing (for example, parts 1, 2, 3, 4, 8), or in the form of load-bearing multilayer panels (for example, parts 5, 6), or as a combination of core trusses and multilayer panels. In this case, a closed body frame structure is formed, each structural part of which is able to effectively resist the shear load applied along the joints of the structural parts due to tension, compression, shear, but not due to the bending of individual power elements. The walls of the cabin 8 during the formation of such a closed structure can complement or replace the functions of the rear 4 or sometimes even the front 3 (depending on the location).

For the example construction shown in the figure, if the driver’s seat is not located on the right side of the bus, but in the middle, it is possible to ensure proper visibility from the driver’s seat in accordance with the requirements of GOST R 51266-99.

The bodywork of the monocoque type bus operates as follows. When the wheels of one of the axles of the bus cross the road, the load occurring on the wheels can be decomposed into a symmetrical one, causing bending of the body, and asymmetric, causing twisting of the body (Pavlovsky Y. “Automobile bodies” - Moscow: “Mechanical Engineering”, 1977, p. 267 and 269). The symmetrical load applied to the wheels, through the suspension device, which is attached, for example, to the wheel arches 7, is transferred to the sidewalls 1 and 2, then to the base 6. Next, the load is redistributed by the base 6 and applied to the payload: passengers standing or sitting on the seats causing their vertical acceleration. The asymmetric load applied to the wheels, for example, of the front axle, is also transmitted to the sidewalls 1 and 2 through the suspension apparatus and wheel niches 7 of the front axle, then to the suspension apparatus and rear axle wheels through the wheel niches 7 of the rear axle. This creates moments of force applied to the sidewalls 1 and 2, trying to turn them in opposite directions in the plane of the sidewalls. Due to the closeness of the proposed design of the monocoque bus body frame along the junction points of the sidewalls 1 and 2, the front end 3, the rear 4, the roof 5, the base 6 and the walls of the passenger compartment 8, shear forces occur that prevent the body from twisting. Because structural parts of the body 1, 2, 3, 4, 5, 8 are made in the form of bridge trusses or multilayer panels, their rods are loaded by tension or compression, and the skin is sheared in its plane, bending of individual power elements is excluded. This ensures high rigidity of the body in bending and torsion modes. The base 6, made, for example, in the form of a bearing multilayer panel, in the twisting mode of the body also undergoes only shear. In the mode of bending the body base 6 is subject to bending on the span between the sidewalls, which is inevitable. In the emergency side tipping mode of the body, the entire crushing load applied to one of the upper corners of the body is perceived by the front 3, rear 4 and interior walls 8. Due to the fact that the structural parts of the body 3, 4 and 8 are made in the form of bridge trusses or multi-layer panels , they effectively resist the compression of their diagonals, demonstrating the high rigidity of the structure, thereby increasing its passive safety.

A detailed analysis of the proposed design (O. Voronkov “Improving the weight, stiffness and strength indicators of bus bodies by using the properties of monocoque-type structures: dissertation for the degree of candidate of technical science - NSTU, Nizhny Novgorod, 2014) confirms the validity of the proposed design solutions and their prospects.

Claims (1)

A monocoque type bus body frame containing a front, left and right sidewalls, a base, a roof, a rear and transverse partitions of a passenger compartment, characterized in that all of the listed components are made in the form of reinforced panels and together form a closed structure of the body frame designed in such a way that when this structure is loaded with a torsional load, the individual rods of this structure experience a mainly tensile or compressive load, but not flexural, and the skin and panels experience a shear load in and x plane.

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