Patent Application
20250117535
The invention belongs to the technical field of cabs for engineering machines, and relates to an optimal design method for a middle cross beam of an ROPS framework and a cab for engineering machines.
An ROPS framework has become a standard configuration of the cab of engineering machines which work in severe environments. According to test requirements, the ROPS framework should meet the loading requirements of lateral, vertical and longitudinal loads and lateral load energy. During lateral loading, the cab is elastic-plastically deformed, plastic hinges appear at positions, where the bending moment is maximum or the structure is weak, of the framework to realize large lateral deformation displacement of the framework, which is beneficial for the absorption of lateral impact loads.
A middle cross beam can increase the number of plastic hinges to greatly improve the load capacity of the ROPS framework, but different height dimensions and sectional dimensions of the middle cross beam are designed in vehicle plants. According to a traditional design method, designers construct an ROPS framework based on empirical data and then optimize the structure based on simulation analysis. However, due to the inadequate experience of designers and the long design cycle, a quick optimal design method is urgently needed.
Objective: to overcome the defects of the prior art, the invention provides an optimal design method for a middle cross beam of an ROPS framework and a cab for engineering machines.
The invention provides a method for designing the height position of a middle cross beam of anROPS framework, and also provides a method for designing the optimal ratio of the sectional inertia moment of the middle cross beam to the sectional inertia moment of pillars of the ROPS framework, such that lightweight design of the ROPS framework is realized.
The invention provides an optimal ROPS framework structure by analyzing the loading features of an ROPS test.
Technical solution: the technical solution adopted by the invention to solve the above technical problems is as follows:
In some embodiments, the ratio of a height dimension U of the middle cross beam to a length dimension L of the D-pillars is n1, and n1 ranges from 0.45 to 0.55.
In some embodiments, the ratio of a sectional inertia moment of the middle cross beam to a sectional inertia moment of the D-pillars is n2, and n2 ranges from 1.15 to 1.45.
In a second aspect, the invention provides an optimal design method for the middle cross beam of the axially symmetric ROPS framework, which comprises:
In some embodiments, the length dimension W of the middle cross beam is 1.45 m-1.6 m, and the length dimension L of the corresponding pillars is 1.65 m-1.9 m.
In some embodiments, the optimal height dimension relation of the middle cross beam is Ld=n1·L. Further, n1 ranges from 0.45 to 0.55.
In some embodiments, an optimal design relation of the middle cross beam is Imiddle_cross beam=n2·Ipillar. Further, the ratio n2 of the sectional inertia moment of the middle cross beam to the sectional inertia moment of the corresponding pillars ranges from 1.15 to 1.45.
In a third aspect, the invention further provides a cab for engineering machines, which comprises the axially symmetric ROPS framework.
Beneficial effects: according to the optimal design method for the middle cross beam of the ROPS framework and the cab for engineering machines, the optimal height dimension of the middle cross beam and the optimal ratio of the sectional inertia moment of the middle cross beam to the sectional inertia moment of the corresponding pillars are obtained by analyzing the structural mechanics model. The method can greatly shorten the design time of the ROPS framework and improve the design quality of the ROPS framework. The invention has the following advantages:
In the figures: 1, pillar, 2, top cross beam; 3, middle cross beam; 4, bottom cross beam; 5, corner bracket; 6, limiting device.
The technical solutions of the embodiments of the invention will be clearly and completely described below in conjunction with the accompanying drawings of these embodiments. Obviously, the embodiments in the following description are merely illustrative ones, and are not all possible ones of the invention. The following description of at least one illustrative embodiment is merely explanatory, and should not be construed as any limitation of the invention or the application or use of the invention. All other embodiments obtained by those ordinarily skilled in the art according to the following ones without creative labor should fall within the protection scope of the invention.
Unless otherwise expressly stated, the relative arrangement of components and steps, numeral expressions and numerical values expounded in the embodiments of the invention are not intend to limit the scope of the invention. Moreover, it should be understood that, for the sake of convenient description, the components in the drawings are not drawn according to actual dimension scale. Techniques, methods and devices known by those ordinarily skilled in related art may not be discussed in detail, and in proper cases, these techniques, method and devices should be construed as one part of the granted specification. In all examples illustrated and discussed here, any specific value should be interpreted as illustrative rather than restrictive. Thus, other examples of the illustrative embodiments may have different values. It should be noted that similar reference signs and alphabets represent similar items in the drawings below. Thus, once one item is defined in one drawing, it will not be further discussed in subsequent drawings.
In the description of the disclosure, it should be understood that terms such as “first” and “second” are used for defining parts merely for the purpose of distinguishing corresponding parts. Unless otherwise stated, these terms have no special meanings, and should not be construed as limitations of the protection scope of the disclosure.
In the description of the application, it should be understood that terms such as “central”. “longitudinal”, “cross”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner” and “outer” are used to indicate directional or positional relations based on the accompanying drawings merely for the purpose of facilitating and simplifying the description, and do not indicate or imply that devices or elements referred to must be in a specific direction, or be configured and operated in a specific direction, so they should not be construed as limitations of the contents protected by the invention.
On the basis that the strictest requirement of the ROPS tests is the lateral loading test, to facilitate lateral load transfer, a middle cross beam reinforcing structure of an ROPS framework shown in
An axially symmetric and closed “ring” framework structure comprises pillars 2, top cross beams 2, a middle cross beam 3 and bottom cross beams 4; one end of each top cross beam is connected to a top end of one of two pillars, and the other end of the top cross beam is connected to a top end of the other one of the two pillars; one end of each bottom cross beam is connected to a bottom end of one of two pillars, and the other end of the bottom cross beam is connected to a bottom end of the other one of the two pillars; two ends of the middle cross beam are connected to inner sides of middle portions of two pillars 1, and a third top cross beam, the middle cross beam and a third bottom cross beam are arranged in parallel, such that the closed “ring” framework structure is formed.
In some embodiments, corner brackets 5 are disposed at joints of the pillars 1, the top cross beams 2 and the middle cross beam 3, and a limiting device 6 is disposed at the bottom of the cab ROPS framework.
In some embodiments, as shown in
Wherein, the pillars comprise A-pillars 10, B-pillars 20, and D-pillars 30; the cross beams comprise top cross beams and bottom cross beams; the longitudinal beams comprise top longitudinal beams and bottom longitudinal beams;
The two A-pillars 10 are connected through a first top cross beam 11 and a first bottom cross beam 12 to form a closed rectangular A-ring;
The two B-pillars 20 are connected through a second top cross beam 21 and a second bottom cross beam 22 to form a closed rectangular B-ring;
The two D-pillars 30 are connected through a third top cross beam 31 and a third bottom cross beam 32 to form a closed rectangular D-ring;
Two ends of the middle cross beam 60 are connected to inner sides of middle portions of the two D-pillars respectively, and the third top cross beam, the middle cross beam and the third bottom cross beam are arranged in parallel;
Four corners of the A-ring and corresponding four corners of the B-ring are connected through a first top longitudinal beam 41 and a first bottom longitudinal beam 42, and four corners of the B-ring and corresponding four corners of the D-ring are connected through a second top longitudinal beam 51 and a second bottom longitudinal beam 52, such as a closed spatial framework structure is formed.
The A-ring, the B-ring and the D-ring are rectangular structures, and the whole ROPS framework is an axially symmetric structure.
In some embodiments, the ratio of a height dimension Ld of the middle cross beam to a length dimension L of the D-pillars is n1, and n1 ranges from 0.45 to 0.55; the ratio of the sectional inertia moment of the middle cross beam to the sectional inertia moment of the D-pillars is n2, and n2 ranges from 1.15 to 1.45. The ROPS framework is designed through an optimal design method in Embodiment 2.
Wherein, the longitudinal beams comprise top longitudinal beams and bottom longitudinal beams; to guarantee the flatness of the bottom of the whole ROPS framework, the bottom longitudinal beams and the bottom cross beams are basically located on a same plane (for example, the bottom longitudinal beams and the bottom cross beams are arranged horizontally); however, the length of the A-pillars, the length of the B-pillars and the length of the D-pillars are not definitely identical, so the top longitudinal beams and the top cross beams are not definitely located on a same plane.
As shown in
Analyzing the bending stress of the portal hyperstatic structural mechanics model by means of the structural mechanics software to obtain the ratio n2 of the sectional inertia moment of the middle cross beam to the sectional inertia moment of the corresponding pillars when the height dimension Ld of the middle cross beam is optimal and the maximum bending stress of the middle cross beam is equal to the maximum bending stress of the corresponding pillars of the ROPS framework, wherein n2 ranges from 1.15 to 1.45;
Determining a height position of the middle cross beam of the ROPS framework according to the optimal height dimension relation of the middle cross beam, and selecting profiles of the middle cross beam and the corresponding pillars according to the profile sectional parameter design relation of the middle cross beam.
The optimal height dimension relation of the middle cross beam is related to the outline dimension of the ROPS framework, is an inherent attribute of the ROPS framework, and is used for guiding the optimal design of the middle cross beam of the ROPS framework. Outline dimensions of common machines can be summarized according to the design method of the invention to establish an optimal design relation database for all cab ROPS frameworks.
A cab for engineering machines comprises the ROPS framework in Embodiment 1, which is designed through the optimal design method for the middle cross beam of the ROPS framework in Embodiment 2.
In actual application, the length dimension W (W is 1.45 m-1.6 m) of the middle cross beam is the width dimension of the cab, and in case where the middle cross beam is simplified as a portal hyperstatic structural mechanics model of a simply supported beam, because the simply supported beam does not have a width, the length dimension W of the middle cross beam is used as the width dimension of the cab.
The engineering machines may be hydraulic excavators, loaders, road rollers, land levelers and the like, and have all the advantages of the ROPS framework provided by the embodiments of the disclosure.
The above embodiments are merely preferred ones of the invention. It should be pointed out that those skilled in the art can make various improvements and embellishments without departing from the principle of the invention, and all these improvements and embellishments should also fall within the protection scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202210749401.1 | Jun 2022 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2022/108855 | 7/29/2022 | WO |
