Construction machine

Abstract

The utility model relates to engineering machinery technical field discloses an engineering machinery, include: machinery main body, the reducer is set up in machinery main body, engine is connected with the reducer through transmission belt, the protective cover includes protective cover main part and fixed support, and fixed support is connected with protective cover main part, and protective cover main part is fixed in the shell of engine through fixed support, and the protective cover main part covers and sets up in transmission belt, wherein, the protective cover main part is injection moulded piece, and the natural frequency of protective cover main part is less than the exciting frequency of engine, and the natural frequency of protective cover main part is less than 42.3Hz. The utility model can solve the problem that the metal protective cover weld cracks in the past.

Description

Technical Field

[0001] This utility model relates to the field of engineering machinery technology, specifically to engineering machinery. Background Technology

[0002] In construction machinery, the engine and reducer typically transmit power via a drive belt (such as a belt). Exposed drive belts are prone to collisions with debris, posing safety risks. Therefore, protective covers are required.

[0003] The protective cover in the relevant technology is made of metal plate welded together. During use, the weld seam of the protective cover is prone to cracking, causing the protection to fail. Utility Model Content

[0004] In view of this, the present invention provides an engineering machinery to solve the problem of cracking of the weld seam of the existing protective cover, which leads to the failure of the protection.

[0005] In a first aspect, this utility model provides an engineering machine, comprising: a mechanical body; a reducer disposed on the mechanical body; an engine connected to the reducer via a transmission belt; and a protective cover, comprising a protective cover body and a fixed bracket, the fixed bracket being connected to the protective cover body, the protective cover body being fixed to the housing of the engine via the fixed bracket, and the protective cover body covering the transmission belt, wherein the protective cover body is an injection molded part, the natural frequency of the protective cover body is less than the excitation frequency of the engine, and the natural frequency of the protective cover body is less than 42.3Hz.

[0006] Beneficial effects: When the engine's excitation frequency coincides with (is equal to) the natural frequency of the protective shield, vibration energy is continuously input into the shield, causing a sharp increase in the shield's vibration amplitude. This large-amplitude vibration generates significant noise and creates alternating dynamic stress within the shield, leading to material fatigue, cracks, and even breakage. It can also cause the bolts and nuts securing the shield to loosen or fall off. Continuous, violent shaking may also cause the shield to collide and rub against other components, resulting in damage and ultimately, protective failure. By ensuring the natural frequency of the shield body is lower than the engine's excitation frequency, thus avoiding resonance between the shield body and the engine, the risk of the shield detaching or breaking is reduced, improving protective reliability and reducing noise.

[0007] In some embodiments, the inherent frequency of the protective cover body is less than or equal to 29.9 Hz.

[0008] Beneficial effects: While avoiding the engine's vibration frequency, it further helps to reduce the weight and material cost of the protective cover body.

[0009] In some embodiments, the fixed bracket includes a first bracket and a second bracket, both of which are fixedly connected to a first surface of the protective cover body along the thickness direction, and the first bracket and the second bracket are spaced apart.

[0010] Beneficial effects: The protective cover is fixed to the engine casing by two brackets, which can improve the stability of the protective cover, prevent the protective cover from shifting or falling off due to vibration, and improve the reliability of protection.

[0011] In some embodiments, the fixing bracket further includes a third bracket, which is fixedly connected to the peripheral side of the protective cover body.

[0012] Beneficial effects: The protective cover is fixed to the engine casing by three brackets, which can further improve the stability of the protective cover, prevent the protective cover from shifting or falling off due to vibration, and further improve the reliability of protection.

[0013] In some embodiments, the first bracket and the second bracket are spaced apart in a vertical direction, and the third bracket is located between the first bracket and the second bracket in the vertical direction.

[0014] Beneficial effects: It can prevent the protective cover from shifting in the up, down, left, and right directions, further improve the stability of the protective cover, prevent the protective cover from shifting or falling off due to vibration, and further improve the reliability of protection.

[0015] In some embodiments, the first and second surfaces of the protective cover body, which are opposite each other along the thickness direction, are both planes.

[0016] Beneficial effects: The main body of the protective cover is flat on both sides and has no reinforcing ribs. Compared with the previous metal protective covers that required reinforcing ribs, it can simplify the structure, reduce material costs, and also reduce the natural frequency of the main body of the protective cover.

[0017] In some embodiments, the two ends of the fixing bracket are detachably connected to the protective cover body and the engine, respectively.

[0018] Beneficial effects: Compared to welding, detachable connections can prevent stress concentration from causing the fixed bracket to crack and fail.

[0019] In some embodiments, the fixing bracket is a steel plate.

[0020] Beneficial effects: The steel fixing bracket can improve the connection strength, and since it is made of a different material from the protective cover body, it reduces the risk of the fixing bracket becoming loose or falling off due to excessive amplitude caused by resonance between the two.

[0021] In some embodiments, the thickness of the protective cover body is 1.5mm to 5mm.

[0022] Beneficial effects: If the thickness is too small, less than 1.5mm, the protective cover will be weak and prone to deformation. If the thickness is too large, greater than 5mm, the cost of the protective cover will increase and injection molding defects such as shrinkage marks and internal air holes will occur, affecting the injection molding quality. Therefore, the thickness of the protective cover body is 1.5mm~5mm, which can ensure the strength of the protective cover, facilitate molding, reduce costs, and also help the natural frequency of the protective cover body to avoid the excitation frequency of the engine. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the structure of the protective cover according to an embodiment of the present utility model; Figure 2 This is a schematic diagram of the structure of a protective cover according to another embodiment of the present invention.

[0025] Explanation of reference numerals in the attached figures: 10-Main body of protective cover; 20-Fixed bracket; 21-First bracket; 22-Second bracket; 23-Third bracket; 101-First side. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0027] The transmission belt protective cover in the relevant technology is made of metal plate welded together. The welding deformation is large, which causes cracks at the weld during use, resulting in the failure of protection.

[0028] Research has shown that since the protective cover is usually installed on the engine casing, the vibration generated by the engine operation is transmitted to the protective cover, causing the protective cover to vibrate and crack the weld. Further research has shown that when the engine's excitation frequency coincides with (is equal to) the natural frequency of the protective cover, the vibration energy will be continuously input into the protective cover, causing the vibration amplitude of the protective cover to increase sharply. The large amplitude vibration will aggravate the cracking of the protective cover weld and eventually lead to the failure of the protection.

[0029] To address this, the material of the protective cover was replaced with injection-molded parts, solving the problem of weld cracking in the previous metal welded parts. At the same time, the natural frequency of the protective cover was reduced to avoid the excitation frequency of the engine, which can prevent resonance between the protective cover and the engine. This reduces the risk of alternating dynamic stress caused by large vibration amplitude due to resonance, which could eventually lead to material fatigue, cracking, or even breakage. It can also reduce the weight of the protective cover.

[0030] The following is combined with Figures 1 to 2 The embodiments of this utility model will be described below.

[0031] According to an embodiment of this utility model, an engineering machine is provided, including a machine body, a reducer, an engine, and a protective cover. The reducer is disposed on the machine body. The engine is connected to the reducer via a transmission belt. The protective cover includes a protective cover body 10 and a fixed bracket 20. The fixed bracket 20 is connected to the protective cover body 10, and the protective cover body 10 is fixed to the engine via the fixed bracket 20. The protective cover body 10 covers the transmission belt. The protective cover body 10 is an injection-molded part, and the natural frequency of the protective cover body 10 is lower than the natural frequency of the engine.

[0032] Construction machinery can include earthmoving machinery, compaction machinery, hoisting machinery, piling machinery, concrete machinery, road machinery, mining machinery, and tunnel machinery. Earthmoving machinery includes excavators, loaders, bulldozers, graders, scrapers, and trenchers. Compaction machinery includes road rollers and tampers. Hoisting machinery includes truck cranes, tower cranes, and crawler cranes. Piling machinery includes pile drivers, rotary drilling rigs, and static pile drivers. Concrete machinery includes concrete pump trucks, mixer trucks, and pavers. Tunnel machinery includes tunnel boring machines, rock drilling rigs, and tunnel boring machines. In some embodiments, the construction machinery may be a skid steer loader.

[0033] The engine drives the reducer to rotate via a drive belt, thereby driving the main body of the machine to perform various operations. For example, it drives a skid steer loader to move, push, shovel, and scrape. The drive belt can be a belt. The belt is wound around the pulleys of the engine and the reducer.

[0034] The protective cover, consisting of a main body 10, covers the exposed drive belt to ensure safety. The protective cover is fixed to the engine housing by mounting brackets 20. One or more mounting brackets 20 may be provided. The mounting brackets 20 can be detachably connected to the engine housing, for example, using fasteners such as bolts or screws. The mounting brackets 20 can be made of metal, such as steel.

[0035] The main body 10 of the protective cover is an injection-molded part made of plastic, which can be integrally molded through injection molding. Compared with metal sheet welding, this reduces the overall weight of the protective cover and lowers the risk of cracking. The injection-molded part can be made of polyethylene, polypropylene, polystyrene, acrylonitrile-butadiene-styrene copolymer, etc.

[0036] The natural frequency of the protective cover body 10 is less than the excitation frequency of the engine; that is, the natural frequency of the protective cover body 10 is not equal to the excitation frequency of the engine. The excitation frequency of the engine ranges from 42.3 Hz to 81 Hz.

[0037] The natural frequencies of the protective cover body 10 and the engine excitation frequency can be measured using a frequency measuring instrument via a sweep frequency method or a hammer impact method. The second-order excitation frequency of the engine measured by the frequency measuring instrument is taken as the engine's excitation frequency. The second-order natural frequency of the protective cover body 10 measured by the frequency measuring instrument is taken as the natural frequency of the protective cover body. The natural frequency of the protective cover body 10 can be reasonably adjusted through its mass, shape, and material.

[0038] When the engine's excitation frequency coincides with (is equal to) the protective shield's natural frequency, vibration energy will be continuously input into the protective shield, causing the protective shield's vibration amplitude to increase sharply. Large-amplitude vibration will cause the entire protective shield to generate significant noise, and at the same time, it will generate alternating dynamic stress inside the protective shield, causing the material to crack or even break due to fatigue. It will also cause the bolts and nuts fixing the protective shield to loosen or even fall off. Continuous violent shaking may also cause the protective shield to collide and rub against other components, causing damage and ultimately leading to protective failure.

[0039] By ensuring that the natural frequency of the protective cover body 10 is lower than the excitation frequency of the engine, the natural frequency of the protective cover body 10 avoids the excitation frequency of the engine. This prevents resonance between the protective cover body 10 and the engine, reduces the risk of the protective cover falling off or breaking, improves the reliability of protection, and also reduces the weight of the protective cover and reduces noise.

[0040] In some embodiments, the natural frequency of the protective cover body 10 is less than 42.3 Hz. This not only avoids the excitation frequency of the engine and prevents resonance, but also helps to reduce the weight of the protective cover body 10 and lower material costs.

[0041] In some embodiments, the natural frequency of the protective cover body 10 is less than or equal to 29.9 Hz. This avoids the excitation frequency of the engine and further helps to reduce the weight and material cost of the protective cover body 10.

[0042] In some embodiments, the fixed bracket 20 includes a first bracket 21 and a second bracket 22. Both the first bracket 21 and the second bracket 22 are fixedly connected to a first surface 101 along the thickness direction of the protective cover body 10, and the first bracket 21 and the second bracket 22 are spaced apart. The protective cover body 10 has a first surface 101 and a second surface 102 opposite to each other along the thickness direction. The first surface 101 is the side facing the transmission belt, i.e., the inner side, and the second surface 102 is the side facing away from the transmission belt, i.e., the outer side.

[0043] For example, the first bracket 21 and the second bracket 22 can be bent structures, and the two ends can be fixed by fasteners such as bolts and nuts.

[0044] The protective cover is fixed to the engine casing by two brackets, which can improve the stability of the protective cover, prevent the protective cover from shifting or falling off due to vibration, and improve the reliability of protection.

[0045] In some embodiments, the first surface 101 and the second surface 102 of the protective cover body 10 are both planar. That is, neither surface has a reinforcing rib structure.

[0046] In some embodiments, the fixing bracket 20 further includes a third bracket 23, which is fixedly connected to the peripheral side of the protective cover body 10.

[0047] The protective cover is fixed to the engine casing by three brackets, which can further improve the stability of the protective cover, prevent the protective cover from shifting or falling off due to vibration, and further improve the reliability of protection.

[0048] In some embodiments, the first bracket 21 and the second bracket 22 are spaced apart in the vertical direction, and the third bracket 23 is located between the first bracket 21 and the second bracket 22 in the vertical direction.

[0049] In this way, the protective cover can be prevented from shifting in the up, down, left, and right directions, which can further improve the stability of the protective cover, prevent the protective cover from shifting or falling off due to vibration, and further improve the reliability of protection.

[0050] In some embodiments, the two ends of the mounting bracket 20 are detachably connected to the protective cover body 10 and the engine, respectively. This detachable connection is achieved, for example, using fasteners such as bolts and screws. Compared to welding, this prevents the risk of stress concentration causing the mounting bracket 20 to crack.

[0051] In some embodiments, the thickness of the protective cover body 10 is 1.5mm to 5mm. The thickness of the protective cover body 10 can be any one of 1.5mm, 2mm, 3mm, 4mm, and 5mm, or any value between two of them. If the thickness is too small, less than 1.5mm, the protective cover may lack strength and be prone to deformation. If the thickness is too large, greater than 5mm, the cost of the protective cover will increase and injection molding defects such as shrinkage marks and internal pores may occur, affecting the injection molding quality. Therefore, the thickness of the protective cover body 10 is 1.5mm to 5mm, which ensures the strength of the protective cover, facilitates molding, reduces costs, and also helps the natural frequency of the protective cover body to avoid the excitation frequency of the engine.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application, are intended to cover non-exclusive inclusion. In the description of embodiments of this application, technical terms such as "first," "second," etc., are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of embodiments of this application, "a plurality of" means two or more, unless otherwise expressly and specifically defined. The reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0053] In the description of the embodiments of this application, the technical terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "circumferential," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed, operated, or used in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0054] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0055] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and all such modifications and variations fall within the scope of the present invention.

Claims

1. An engineering machinery, characterized in that, include: Mechanical body; The speed reducer is disposed on the mechanical body; An engine, which is connected to the reducer via a drive belt; The protective cover includes a protective cover body (10) and a fixing bracket (20). The fixing bracket (20) is connected to the protective cover body (10). The protective cover body (10) is fixed to the housing of the engine through the fixing bracket (20). The protective cover body (10) covers the transmission belt. The protective cover body is an injection molded part. The natural frequency of the protective cover body is less than the excitation frequency of the engine. The natural frequency of the protective cover body (10) is less than 42.3 Hz.

2. The engineering machinery according to claim 1, characterized in that, The natural frequency of the protective cover body (10) is less than or equal to 29.9 Hz.

3. The engineering machinery according to claim 1, characterized in that, The fixed bracket (20) includes a first bracket (21) and a second bracket (22). The first bracket (21) and the second bracket (22) are both fixedly connected to the first surface of the protective cover body (10) along the thickness direction, and the first bracket (21) and the second bracket (22) are spaced apart.

4. The engineering machinery according to claim 3, characterized in that, The fixed bracket (20) also includes a third bracket (23), which is fixedly connected to the periphery of the protective cover body (10).

5. The engineering machinery according to claim 4, characterized in that, The first bracket (21) and the second bracket (22) are spaced apart in the vertical direction, and the third bracket (23) is located between the first bracket (21) and the second bracket (22) in the vertical direction.

6. The engineering machinery according to claim 1, characterized in that, The first surface (101) and the second surface of the protective cover body (10) are both planar along the thickness direction.

7. The engineering machinery according to claim 1, characterized in that, The two ends of the fixed bracket (20) are detachably connected to the protective cover body (10) and the engine, respectively.

8. The engineering machinery according to claim 7, characterized in that, The two ends of the fixed bracket (20) are respectively connected to the protective cover body (10) and the engine via bolt and nut assemblies.

9. The engineering machinery according to claim 1, characterized in that, The fixed bracket is made of steel plate.

10. The engineering machinery according to claim 1, characterized in that, The thickness of the main body of the protective cover is 1.5mm to 5mm.

Images