Generator set axis centering method

Abstract

The application discloses a generator set axis centering method, and the generator set comprises an internal combustion engine, a generator, an intermediate support and a chassis, the intermediate support has an upper part and a lower part which jointly define a crankshaft mounting hole, the upper part and the lower part are fixedly connected through a support butt joint bolt, and the lower part is fixedly connected to the chassis through a support fixing bolt; the method comprises the following steps: determining the specifications of the support butt joint bolt and the support fixing bolt; adjusting the relative positions of the crankshaft of the internal combustion engine, the crankshaft mounting hole of the intermediate support and the rotating shaft of the generator, so that the axes of the three are centered; fixing the internal combustion engine and the generator, and fastening the support fixing bolt and the support butt joint bolt with the determined specifications, so that the generator set axis centering is completed; and the specifications of the support butt joint bolt and the support fixing bolt are determined based on a formula. The application can determine the optimal matching scheme of the support butt joint bolt and the support fixing bolt, and can also determine the reasonable size of the intermediate support.

Description

Technical Field

[0001] This invention relates to the field of generator set technology, and more specifically to a method for aligning the shaft of a generator set. Background Technology

[0002] refer to Figure 1 The generator set mainly consists of an internal combustion engine 6, a generator, an intermediate support 3, and a base frame 5. The internal combustion engine 6, generator, and intermediate support 3 are bolted to the base frame 5. The intermediate support 3 supports the crankshaft output shaft 2 of the internal combustion engine 6. During installation, to ensure stable operation of the generator set, the center lines of the generator shaft and the internal combustion engine crankshaft must be perfectly aligned. The intermediate support 3 consists of upper and lower parts, which are connected together by support bolts 1. The crankshaft output shaft 2 passes through the middle of the intermediate support 3 and connects to the generator. The lower part of the intermediate support 3 is fixedly fastened to the base frame 5 by support bolts 4.

[0003] When aligning the generator set's shaft, the relative positions of the internal combustion engine crankshaft, the intermediate support crankshaft mounting holes, and the generator set shaft are first adjusted. After adjustment, the internal combustion engine mounting bolts, generator mounting bolts, support fixing bolts, and support mating bolts are tightened to complete the generator set's alignment. However, when tightening the support mating bolts, due to the large torque and long lever arm, insufficient tightening torque on the support fixing bolts can cause the intermediate support to shift, disrupting the alignment. Therefore, selecting and using appropriately sized support mating bolts and support fixing screws is crucial to ensuring proper alignment of the generator set's shaft. However, currently, the selection and design of support mating bolts and support fixing bolts are based on experience, making it difficult to obtain an optimal solution and wasting time and money. Summary of the Invention

[0004] The main objective of this invention is to provide a method for aligning the shaft of a generator set, thereby solving the problem that in the prior art, the selection and design of support bolts and support fixing bolts based on experience makes it difficult to obtain a better solution and also wastes time and costs.

[0005] According to one aspect of the present invention, a method for aligning the shaft of a generator set is provided. The generator set includes an internal combustion engine, a generator, an intermediate support for supporting the crankshaft of the internal combustion engine, and a base frame. The intermediate support has an upper portion and a lower portion that jointly define a crankshaft mounting hole. The upper and lower portions are fixedly connected by support butt bolts, and the lower portion is fixedly connected to the base frame by support fixing bolts. The method includes:

[0006] Determine the specifications of the supporting bolts and the supporting fixing bolts;

[0007] Adjust the relative positions of the crankshaft of the internal combustion engine, the crankshaft mounting hole of the intermediate support, and the rotating shaft of the generator so that the axes of the three are aligned.

[0008] Secure the internal combustion engine and generator, and tighten the support fixing bolts and support docking bolts of the specified specifications to complete the alignment of the generator set shaft;

[0009] The specifications of the support bolts and the support fixing bolts are determined based on the following formula:

[0010]

[0011] Where D is the nominal diameter of the support bolt, in meters (m); m is the total mass of the intermediate support and crankshaft pressing on the intermediate support, in kilograms (kg); g is the acceleration due to gravity, in N / kg; σ is the fatigue strength of the support bolt, in MPa (MPa); and A is the cross-sectional area of ​​the support bolt, in mm². 2 .

[0012] According to one embodiment of the present invention, the specifications of the support butt bolts and the support fixing bolts are further determined based on the following formula:

[0013]

[0014] Where T is the tightening torque of the supporting bolt, in Nm; k represents the maximum lever arm of the supporting bolt relative to the unit axis; r represents the maximum lever arm of the supporting bolt relative to the unit axis; k and r have the same unit. It does not exceed the predetermined value.

[0015] According to one embodiment of the present invention, No more than 5.

[0016] According to one embodiment of the present invention, it further includes a method based on Determine the dimensions of the intermediate support.

[0017] According to one embodiment of the present invention, the specifications of the support butt bolt and the support fixing bolt include the diameter and / or performance grade of the support butt bolt and the support fixing bolt.

[0018] According to one embodiment of the present invention, the specifications of the support and connecting bolts are first determined, and then the specifications of the support and fixing bolts are determined based on the specifications of the support and connecting bolts and the formula.

[0019] According to one embodiment of the present invention, the specification of the support bolt is M30.

[0020] According to one embodiment of the present invention, the specifications of the support fixing bolt are determined to be: M18, grade 8.8.

[0021] According to one embodiment of the present invention, adjusting the relative positions of the crankshaft of the internal combustion engine, the crankshaft mounting hole of the intermediate support, and the rotating shaft of the generator includes: adjusting based on the measured values ​​of radial runout and end face runout of the crankshaft of the internal combustion engine, the crankshaft mounting hole of the intermediate support, and the rotating shaft of the generator.

[0022] According to one embodiment of the present invention, fixing an internal combustion engine and a generator includes: fastening internal combustion engine mounting bolts and generator mounting bolts.

[0023] In the technical solution of this invention, the specifications of the supporting butt bolts and the supporting fixing bolts are determined by formula, which can realize the optimal design scheme that meets the application requirements, and can quickly determine the bolt specifications, saving time and cost in the selection process. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A partial schematic diagram of the generator set is shown;

[0026] Figure 2 The diagram shows the force analysis of the supporting butt bolt and the supporting fixing bolt according to an embodiment of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to specific examples and the accompanying drawings.

[0028] It should be noted that all uses of "first" and "second" in the embodiments of the present invention are for the purpose of distinguishing two entities or parameters with the same name but different names. It is clear that "first" and "second" are only for the convenience of expression and should not be construed as limiting the embodiments of the present invention. Subsequent embodiments will not explain this in detail.

[0029] refer to Figure 1As mentioned in the background section above, the generator set includes an internal combustion engine 6, a generator, an intermediate support 3 supporting the crankshaft 2 of the internal combustion engine 6, and a base frame 5. The intermediate support 3 has an upper part and a lower part that jointly define a crankshaft mounting hole. The crankshaft 2 passes through the crankshaft mounting hole. The upper part and the lower part are fixedly connected by support butt bolts 1. The lower part is fixedly connected to the base frame 5 by support fixing bolts 4. The internal combustion engine 6 and the generator are also fixedly connected to the base frame 5 by corresponding bolts.

[0030] The inventors of this application recognized that during generator set shaft alignment, after adjusting the relative positions of the internal combustion engine crankshaft, the crankshaft mounting holes of the intermediate support, and the generator shaft, insufficient tightening torque of the support fixing bolts during bolt tightening can cause the intermediate support to shift, disrupting alignment. Therefore, it is necessary to select appropriately sized support connecting bolts and support fixing bolts for tight fit. Simultaneously, to avoid material and space waste, the support fixing bolts cannot be designed to be too large, and their quantity and the dimensions of the intermediate support are also limited. However, current designs are based on experience, making it difficult to achieve a perfect match of the external dimensions of the support connecting bolts, support fixing bolts, and intermediate support, failing to meet the requirements of a compact and rationally designed high-quality solution, and also wasting certain costs. To solve the above problems, this invention proposes one or more embodiments, which are described below.

[0031] This invention proposes a method for aligning the shaft of a generator set, the method comprising:

[0032] Determine the specifications of the supporting bolts and the supporting fixing bolts;

[0033] Adjust the relative positions of the crankshaft of the internal combustion engine, the crankshaft mounting hole of the intermediate support, and the shaft of the generator so that the axes of the three are aligned.

[0034] Secure the internal combustion engine and generator, and tighten the support fixing bolts and support docking bolts of the specified specifications to complete the alignment of the generator set shaft;

[0035] The specifications of the support bolts and the support fixing bolts are determined based on the following formula:

[0036]

[0037] Where D is the nominal diameter of the support bolt, in meters (m); m is the total mass of the intermediate support and crankshaft pressing on the intermediate support, in kilograms (kg); g is the acceleration due to gravity, in N / kg; σ is the fatigue strength of the support bolt, in MPa (MPa); and A is the cross-sectional area of ​​the support bolt, in mm². 2 .

[0038] In some embodiments, the specifications of the support butt bolts and the support fixing bolts are further determined based on the following formula:

[0039]

[0040] Where T is the tightening torque of the supporting bolt, in Nm; k represents the maximum lever arm of the supporting bolt relative to the unit axis; r represents the maximum lever arm of the supporting bolt relative to the unit axis; k and r have the same unit. It does not exceed the predetermined value.

[0041] The inventors of this application realized that, after the support fixing bolts are tightened, if the intermediate support does not move when the support connecting bolts are tightened, the following condition must first be met: the force generated by tightening the support connecting bolts must not exceed the frictional force between the support fixing bolts and the base frame; further, the following condition must be met: the torque generated by tightening the support connecting bolts must not exceed the torque of the frictional force between the support fixing bolts and the base frame. Since the tightening torque of the bolts remains constant, the lever arm is longest when the support connecting bolts and support fixing bolts generate the maximum torque. Through the tightening torque and force analysis of the intermediate support, support connecting bolts, and support fixing bolts, a physical and mechanical force analysis diagram is established, see [see diagram]. Figure 2 .exist Figure 2 In the diagram: 1-supporting bolt; 4-supporting bolt; Fb-friction between the supporting bolt and the base frame; n-number of supporting bolts; Fa-maximum tightening force of the supporting bolt; r-maximum lever arm of the supporting bolt relative to the unit axis; k-lever arm of the supporting bolt relative to the unit axis. This invention is based on... Figure 2 Establish a mathematical model and fit the above formulas ① and ②.

[0042] In embodiments of the present invention, the specifications of the support bolts and the support fixing bolts may include their diameters and / or performance grades. In Formula ①, D (nominal diameter of the support bolt) indicates the specification of the support bolt; σ (fatigue strength of the support fixing bolt) and A (cross-sectional area of ​​the support fixing bolt) indicate the specification of the support fixing bolt. Formula ① indicates a first relationship between the specifications of the support bolts and the support fixing bolts, based on which a preliminary matching scheme for the support bolts and the support fixing bolts can be determined. m (total mass of the intermediate support and crankshaft pressing on the intermediate support) in Formula ① is obtainable, for example, by measurement and / or calculation by consulting a mechanical design manual. In Formula ②, T (tightening torque of the support bolt) and D (nominal diameter of the support bolt) indicate the specification of the support bolt; σ (fatigue strength of the support fixing bolt) and A (cross-sectional area of ​​the support fixing bolt) indicate the specification of the support fixing bolt. Formula ② indicates a second relationship between the specifications of the support bolts and the support fixing bolts, based on which a further matching scheme for the support bolts and the support fixing bolts can be determined. This represents the ratio of the maximum lever arm of the supporting fixing bolt relative to the unit axis to the maximum lever arm of the supporting mating bolt relative to the unit axis. Due to limitations in the dimensions of the intermediate support, The value cannot be too large (exceeding the predetermined value), and can be combined with The value constraints determine the specifications of the support bolts and the support fixing bolts. In some embodiments, No more than 5.

[0043] refer to Figure 2 k indicates the distance from the support fixing bolt to the unit axis, and r indicates the distance from the support mating bolt to the unit axis. The dimensional characteristics of the intermediate support can be defined. Therefore, in the technical solution of this invention, based on the above two relationships, the matching specifications of the support mating bolts and the support fixing bolts can be easily obtained, and the optimal ratio of their maximum lever arms can also be determined. The bottom dimensions of the intermediate support are then designed according to this ratio. This achieves an optimized design that meets the application requirements.

[0044] In some embodiments, the specifications of the support bolts are first determined (which can be based on basic requirements for the support bolts, such as size limitations, to determine their optional specifications), and then the specifications of the support fixing bolts are determined based on the specifications of the support bolts and the above formula. For example, in one embodiment, the specifications of the support bolts are M30, and the specifications of the support fixing bolts are determined to be M18, grade 8.8.

[0045] In some embodiments, adjusting the relative positions of the crankshaft of the internal combustion engine, the crankshaft mounting hole of the intermediate support, and the generator shaft includes adjusting based on measurements of radial runout and end face runout of the crankshaft of the internal combustion engine, the crankshaft mounting hole of the intermediate support, and the generator shaft.

[0046] In some embodiments, securing the internal combustion engine and the generator includes: tightening the internal combustion engine mounting bolts and the generator mounting bolts.

[0047] In summary, this invention proposes a simple, effective, and clear method for selecting and designing the external dimensions of support bolts, support fixing bolts, and intermediate supports, achieving a perfect match between their external dimensions. This makes the selection of the mating specifications of the support bolts and support fixing bolts simpler, more convenient, more reasonable, and clearer, while also making the design dimensions of the bottom of the intermediate support more reasonable.

[0048] The following description is based on specific embodiments.

[0049] Example 1

[0050] For a certain type of generator set, the mass of the crankshaft pressing on the intermediate support is calculated to be 36 kg according to the mechanical design manual. Therefore, the total mass m of the intermediate support and the crankshaft pressing on the intermediate support is 138.9 kg. The support connection bolts are M30 bolts. According to the mechanical design manual, their nominal diameter D is 0.03 m and the tightening torque T is 1275 N·m.

[0051] Substituting the above parameters into equation ①, we get:

[0052] 23.12<σA

[0053] The support fixing bolts are selected as M10, grade 8.8. Referring to the mechanical design handbook, σ is 640MPa and A is 58mm. 2 Substituting it into the above relation, we have

[0054] 23.12<37120

[0055] Satisfying equation ①,

[0056] Substituting the above parameters into equation ②

[0057]

[0058] The above formula is clearly invalid; the lever arm ratio between the supporting bolt and the supporting fixing bolt is too large, which does not meet the design requirements. Therefore, a new supporting fixing bolt should be selected. An M18, 8.8 grade supporting fixing bolt should be selected. Referring to the mechanical design handbook, σ is 640MPa and A is 163mm. 2 Substituting it into equations ① and ②, we have

[0059] 23.12 < 104320

[0060]

[0061] To meet the design and application requirements.

[0062] This allows us to determine the matching specifications of the support bolts and the support fixing bolts, and to design the appropriate dimensions of the bottom of the intermediate support based on the optimal ratio of their lever arms.

[0063] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of the different aspects of the invention as described above exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

Claims

1. A method of aligning the axis of a genset, characterized by, The generator set comprises an internal combustion engine, a generator, an intermediate support supporting a crankshaft of the internal combustion engine, and a chassis, the intermediate support having an upper part and a lower part jointly defining a crankshaft mounting hole, the upper part and the lower part being fixedly connected through a support butt joint bolt, the lower part being fixedly connected to the chassis through a support fixing bolt; the method comprises: determining specifications of the support butt joint bolt and the support fixing bolt; adjusting relative positions of the crankshaft of the internal combustion engine, the crankshaft mounting hole of the intermediate support, and a rotating shaft of the generator, so that axes of the three are aligned; fixing the internal combustion engine and the generator and fastening the support fixing bolt and the support butt joint bolt having the determined specifications, completing alignment of axes of the generator set; wherein the specifications of the support butt joint bolt and the support fixing bolt are determined based on the following formula: wherein, D is the nominal diameter of the support abutment bolt in m; M is the total mass of the intermediate support and the crankshaft pressed on the intermediate support in kg; g is the acceleration due to gravity in N / kg; S is the fatigue strength of the support fixing bolt in MPa; A is the cross-sectional area of the support fixing bolt in mm²; wherein the specifications of the support butt joint bolt and the support fixing bolt are further determined based on the following formula: in, The tightening torque for supporting butt bolts, expressed in Nm; This indicates the maximum lever arm of the supporting fixing bolt relative to the unit axis; This indicates the maximum lever arm of the supporting bolt relative to the unit's axis; and The units are the same. Not exceeding the predetermined value; The method also includes determining the size of the intermediate support based on the size of the intermediate support.

2. The method of claim 1, wherein, No more than 5.

3. The method of claim 1, wherein, the specifications of the support butt joint bolt and the support fixing bolt comprise diameters and / or performance grades of the support butt joint bolt and the support fixing bolt.

4. The method of claim 1, wherein, The specifications of the support butt joint bolt are determined first, and then the specifications of the support fixing bolt are determined based on the specifications of the support butt joint bolt and the formula.

5. The method of claim 1, wherein, The specifications of the support butt joint bolt are M30.

6. The method of claim 5, wherein, The specifications of the support fixing bolt are determined as M18, grade 8.

8.

7. The method of claim 1, wherein, The adjusting of the relative positions of the crankshaft of the internal combustion engine, the crankshaft mounting hole of the intermediate support, and the rotating shaft of the generator comprises adjusting based on measured values of radial runout and end face runout of the three.

8. The method of claim 1, wherein, The fixing of the internal combustion engine and the generator comprises fastening internal combustion engine mounting bolts and generator mounting bolts.

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