Vibration test method for single-bearing-supported high-speed diesel generating set

Abstract

The invention provides a vibration test method for a single-bearing-supported high-speed diesel generating set, and the method comprises the steps: measuring the vibration frequency and amplitude change of a body of the diesel generating set, and the vibration condition of a vibration isolator group of the diesel generating set; judging whether a diesel engine and a generator of the diesel generating set have a poor matching problem or not; by measuring the vibration condition of the vibration isolator set, whether the body and the vibration isolator set are poor in matching or not is judged; by measuring the vibration condition of the body, whether the body and the vibration isolator set have a poor matching problem or not is judged, and whether the rigidity of the connecting box of the diesel generating set has a problem or not is judged; whether the structure and rigidity of the rotor of the generator have problems is judged by measuring the vibration speed of the body. Whether the rotor and the connecting box have problems or not is judged by measuring the vibration condition of the body. According to the method, the influence of the vibration isolators, the connection rigidity and the difference of the installation conditions on the vibration of the unit is evaluated by analyzing the vibration change rule.

Description

Technical Field

[0001] The present invention relates to the technical field of diesel generators, and in particular to a vibration testing method for a high-speed diesel generator set supported by a single bearing. Background Art

[0002] The vibration problem of high-speed diesel generator sets in railway locomotives has attracted wide attention. The main factors affecting the vibration of high-speed diesel generator sets are: shaft alignment, shaft rotation imbalance, diesel engine and main generator connection stiffness, and diesel generator set vibration isolator matching. Taking the above factors into consideration, resonance should be avoided under common working conditions.

[0003] In order to solve the problem of high vibration of single-bearing supported high-speed diesel generator sets, the existing technology has tried and eliminated the diesel engine assembly, vibration isolator layout and adjustment, main generator structure improvement, and assembly process optimization one by one. The existing technology is not only costly, time-consuming, and inefficient in completely solving the problem of excessive vibration, but also has a single method. Each attempt cannot truly achieve single variable control, making the test results uncontrollable.

[0004] The prior art specifically has the following shortcomings: 1. When the diesel generator set vibrates greatly, first check whether the diesel engine and generator are well installed. When checking the installation of the diesel engine and generator, if all the clearances and measurement indicators are within the range, the disadvantages of this method are exposed, because this measurement is a static measurement of the diesel engine when it is cold, and the influence of thermal expansion and contraction and dynamic forces will inevitably cause errors with the static measurement results, affecting the judgment of the results.

[0005] 2. When the diesel engine unit vibrates greatly, the whole machine stiffness and natural frequency can be changed by adjusting or replacing the vibration isolator. However, whether to adjust in the direction of strong stiffness or weak stiffness, the selection calculation of the vibration isolator alone is not enough to draw a conclusion, which will cause misjudgment, because the diesel engine unit must have done the selection calculation of the vibration isolator at the beginning of the design to avoid excessive vibration. However, the selection calculation of the vibration isolator only needs to bring in the center of gravity and moment of inertia of the unit, and consider the unit as pure rigidity. The calculation results are relatively accurate only for the first 6 orders of whole machine vibration. When the large vibration of the unit is not caused by the first 6 orders of modal resonance, it is blind and not targeted to adjust the vibration isolator only by relying on the results of the selection calculation.

[0006] 3. When the vibration of the unit is too large, the method of changing the stiffness of the connecting box between the diesel engine and the generator, changing the connection stiffness, and trying to reduce the vibration has considerable limitations. There is no uniform standard for structural improvement to make the stiffness stronger or weaker. Because the stiffness of the connecting box is the transition between the diesel engine and the motor, its stiffness is too strong or too weak, which will seriously affect the overall mode of the unit. Moreover, the improvement effect of the improved structure in the six degrees of freedom is not consistent. If it cannot be combined with the overall stiffness of the unit for targeted strengthening or weakening, it will inevitably result in a twice the result with half the effort.

[0007] 4. When the vibration of the unit is too large, there are still limitations in trying to change the structure of the rotor, change the rotation frequency, and try to reduce the vibration. The motor rotor and the engine crankshaft together form the shaft system. Changing the rotor structure only affects the torsional vibration and the vibration at the motor bearing. If the whole unit has a large vibration phenomenon, this method will have little effect.

[0008] Therefore, the prior art needs to be improved. Summary of the invention

[0009] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a vibration testing method for a single-bearing supported high-speed diesel generator set. By analyzing the vibration variation law, the influence of differences in vibration isolators, connection stiffness and installation conditions on the vibration of the set is evaluated, empirical laws are formed, and improvement measures are promoted in a targeted manner.

[0010] In order to solve the above technical problems, the present invention adopts the following technical solutions: According to an aspect of the present invention, a vibration test method for a single-bearing supported high-speed diesel generator set is provided, comprising: 1) By measuring the vibration frequency and amplitude changes of the diesel generator set body and the vibration of the vibration isolator group of the diesel generator set, it can be determined whether there is a poor matching problem between the diesel engine and the generator of the diesel generator set; 2) When the vibration of the vibration isolator group of the diesel generator set exceeds the standard range, the vibration of the vibration isolator group is measured to determine whether there is a poor matching problem between the main body and the vibration isolator group; 3) When the vibrations of all the isolators of the isolator group are within the standard range, the vibration of the main body is measured to determine whether there is a poor matching problem between the main body and the isolator group, and whether there is a problem with the stiffness of the connection box of the diesel generator set; 4) By measuring the vibration speed of the main body, it is possible to determine whether there are any problems with the structure and stiffness of the generator rotor.

[0011] 5) Measure the vibration of the body to determine whether there are any problems with the rotor and the connection box.

[0012] In one embodiment of the present invention, in 1), when the vibration frequency of the main body is measured to be the same as the rotor rotation frequency of the generator, and the amplitude of the main body increases with the increase of the rotor rotation speed, and the amplitude of the vibration isolator on one side of the vibration isolator group is greater than the amplitude of the vibration isolator on the other side, it is judged that the diesel engine and the generator are poorly matched.

[0013] In one embodiment of the present invention, in 2), at a certain rotation speed of the generator, it is measured that all the vibration isolators of the vibration isolator group have a uniform increase in first-order amplitude in the vertical direction, and it is determined that the main body and the vibration isolator group are poorly matched.

[0014] In one embodiment of the present invention, in 3), when the generator is measured at a certain rotation speed, the first-order amplitude of the main body in the vertical direction increases, and it is determined that the main body is not matched with the vibration isolator group.

[0015] In one embodiment of the present invention, in 3), when the generator is measured at a certain rotation speed, the first-order amplitude of the body in the vertical direction increases, and it is determined that there is a problem with the vertical stiffness of the connection box.

[0016] In one embodiment of the present invention, in 4), when the vertical vibration of the body does not have a first-order vibration at a certain speed of the motor, and the vibration speed of the body in the vertical direction is measured to exceed the standard range, it is determined that there are problems with the structure and torsional stiffness of the rotor.

[0017] In one embodiment of the present invention, in 5), when the measured lateral amplitude of the body exceeds the standard range, it is determined that there is a problem with the stiffness of the connection box.

[0018] In one embodiment of the present invention, in 5), when the measured lateral amplitude of the body exceeds a standard range, it is determined that there is a problem with the structure of the rotor.

[0019] In one embodiment of the present invention, in 5), when the measured longitudinal amplitude of the body exceeds the standard range, it is determined that there is a problem with the stiffness of the connection box.

[0020] In one embodiment of the present invention, in 5), when the longitudinal amplitude of the body is measured to be beyond a standard range, it is determined that there is a problem with the structure of the rotor.

[0021] By adopting the above technical solution, the present invention has the following advantages compared with the prior art: 1. By analyzing the vibration variation law, evaluate the impact of the difference in vibration isolators, connection stiffness and installation conditions on the unit vibration, form empirical laws, promote targeted improvement measures, form a diesel engine unit vibration assessment method covering the simulation front end to the test terminal, and apply the research results to the design improvement of existing projects.

[0022] 2. By studying the vibration spectrum distribution of existing high-speed diesel engine units, sorting out the existing vibration test data, and through spectrum analysis, transfer path analysis and frequency band contribution analysis, determine the components and main sources that have the greatest impact on vibration, and determine improvement measures.

[0023] 3. By adopting simulation methods such as finite element, multi-body dynamics and statistical energy analysis, the vibration variation law at the corresponding positions of the diesel engine and generator at various frequencies within the full speed range under different hardness isolator combinations, different connection box stiffness of the diesel engine and generator, and different installation conditions of the test bench and loading and use is studied to quantitatively evaluate the advantages and disadvantages of each solution, determine practical engineering solutions, shorten the R&D cycle to the greatest extent, and reduce rework costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A flow chart of a vibration testing method for a single-bearing supported high-speed diesel generator set provided by the present invention is shown. DETAILED DESCRIPTION

[0025] It should be understood that the embodiments of the present invention shown in the exemplary embodiments are only illustrative. Although only a few embodiments are described in detail in the present invention, it is easy for those skilled in the art to appreciate that multiple modifications are feasible without actually departing from the teaching of the subject matter of the present invention. Accordingly, all such modifications should be included within the scope of the present invention. Without departing from the gist of the present invention, other replacements, modifications, changes and deletions may be made to the design, operating conditions and parameters of the following exemplary embodiments.

[0026] like Figure 1 As shown, the present invention provides a vibration test method for a single-bearing supported high-speed diesel generator set, including: 1) by measuring the vibration frequency and amplitude changes of the diesel generator set body and the vibration of the vibration isolator group of the diesel generator set, to determine whether the diesel engine and the generator of the diesel generator set have a poor matching problem; 2) when the vibration of the vibration isolator group of the diesel generator set exceeds the standard range, by measuring the vibration of the vibration isolator group, to determine whether the body and the vibration isolator group have a poor matching problem; 3) when the vibrations of all the vibration isolators of the vibration isolator group are within the standard range, by measuring the vibration of the body, to determine whether the body and the vibration isolator group have a poor matching problem, and to determine whether the stiffness of the connection box of the diesel generator set has a problem; 4) by measuring the vibration speed of the body, to determine whether the structure and stiffness of the rotor of the generator have a problem. 5) by measuring the vibration of the body, to determine whether there are problems with the rotor and the connection box.

[0027] The above technical solution of the present invention, through the analysis of vibration variation law, evaluates the influence of the difference of vibration isolators, connection stiffness and installation conditions on the vibration of the unit, forms empirical law, and promotes improvement measures in a targeted manner. Improvement measures include, for example: re-matching the vibration isolators, adjusting the stiffness of the connection box and changing the motor rotor structure, through which the problem of large vibration of the diesel engine unit can be reduced. The present invention can be carried out by combining vibration test analysis with vibration simulation prediction.

[0028] In the above method, in 1), when the vibration frequency of the body is measured to be the same as the rotor rotation frequency of the generator, and the amplitude of the body increases with the increase of the rotor rotation speed, and the amplitude of the isolator on one side of the isolator group is greater than the amplitude of the isolator on the other side, it is judged that the diesel engine and the generator are poorly matched. The prior art cannot judge the phenomenon of poor installation of the diesel generator set by measuring the hot gap. The present invention judges whether the current generator and the diesel engine have poor installation matching by judging the vibration response change law at each isolator position.

[0029] In the above method, in 2), at a certain rotation speed of the generator, it is measured that all the vibration isolators of the vibration isolator group have an increased first-order amplitude in the vertical direction, and it is determined that the main body and the vibration isolator group are poorly matched, and the vibration isolators need to be reselected and matched.

[0030] In the above method, in 3), the first-order amplitude of the generator body in the vertical direction increases at a certain speed, and it is judged that the body and the vibration isolator group do not match. This situation shows that even if the vibration at the vibration isolator is within the range, there is still resonance, which is not good for the vibration of the generator body, and the vibration isolator needs to be re-matched.

[0031] In the above method, in 3), the first-order amplitude of the generator body in the vertical direction increases at a certain speed, and it is judged that there is a problem with the vertical stiffness of the connection box. This situation shows that even if the vibration at the vibration isolator is within the range, there is still resonance, which is not conducive to the vibration of the generator body, and the vertical stiffness of the connection box needs to be enhanced.

[0032] In the above method, in 4), when the vertical vibration of the body does not have the first-order vibration at a certain speed of the motor, and the vibration speed of the body in the vertical direction is measured to exceed the standard range, it is judged that there are problems with the structure and torsional stiffness of the rotor. Accordingly, you can try to improve the structure of the rotor, change the torsional stiffness of the shaft system, and then try to reduce the vibration of the unit.

[0033] In the above method, in 5), when the measured lateral amplitude of the body exceeds the standard range, it is determined that there is a problem with the stiffness of the connection box.

[0034] In the above method, in 5), when the measured lateral amplitude of the body exceeds the standard range, it is determined that there is a problem with the structure of the rotor.

[0035] In the above method, in 5), when the measured longitudinal amplitude of the body exceeds the standard range, it is determined that there is a problem with the stiffness of the connection box.

[0036] In the above method, in 5), when the longitudinal amplitude of the body is measured to be beyond the standard range, it is determined that there is a problem with the structure of the rotor.

[0037] The above technical solution of the present invention is described in detail below through specific embodiments.

[0038] Example: The vibration test equipment includes a data acquisition system, acquisition software, a three-axis acceleration sensor, and a force hammer. The vibration simulation is performed using finite element and multi-body dynamics analysis software. Vibration test data on the isolator position and the main generator body are obtained through speed increase and decrease of the diesel engine unit and steady-state vibration tests under various operating conditions. When the vibration patterns at each isolator are consistent, and a harmonic vertical vibration significantly increases at the frequency of the operating speed, it can be considered that there is a problem with the isolator matching of the diesel engine unit and re-matching is required. When there is no obvious sudden increase in order after re-matching, it means that the isolator is well matched. The selected isolator must undergo a vibration test. The passing of the selection calculation does not mean that the whole machine will not resonate after actual installation. The actual measurement should prevail.

[0039] All the improved designs are tested by actual means, which are not the best choice in terms of cost, cycle, and time. Simulation test simulation is the most economical and efficient prediction method at present. By building a finite element model, considering the actual connection stiffness and detailed structure, shortening the R&D cycle and combining it with experimental testing will achieve twice the result with half the effort.

[0040] When the results of the vibration isolator selection calculation cannot accurately predict the phenomenon of the whole machine resonance of the diesel engine unit, it is necessary to consider that vertical decoupling is the main reason for the above phenomenon, mainly due to the insufficient connection stiffness between the diesel engine and the generator. At this time, the vertical stiffness of the connection structure should be strengthened. When formulating measures to solve the excessive vibration of the diesel engine unit, first of all, the vibration data of the vibration isolator position and the generator body should be analyzed, and the causes should be formulated and investigated from several angles, including the location of the large vibration, the direction of the vibration, and the harmonic composition of the vibration. Finally, the problem of large vibration of the diesel engine unit can be reduced by re-matching the vibration isolator, adjusting the stiffness of the connection box, and changing the motor rotor structure.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of implementation of the present invention. If the present invention is modified or replaced by equivalents without departing from the spirit and scope of the present invention, it should be included in the protection scope of the claims of the present invention.

Claims

1. A vibration test method for a single-bearing supported high-speed diesel generator set, characterized in that: include: 1) By measuring the vibration frequency and amplitude changes of the diesel generator set body and the vibration of the vibration isolator group of the diesel generator set, it is determined whether there is a poor matching problem between the diesel engine and the generator of the diesel generator set; 2) When the vibration of the vibration isolator group of the diesel generator set exceeds the standard range, the vibration of the vibration isolator group is measured to determine whether there is a poor matching problem between the main body and the vibration isolator group; 3) When the vibrations of all the vibration isolators of the vibration isolator group are within the standard range, the vibration of the main body is measured to determine whether there is a poor matching problem between the main body and the vibration isolator group, and whether there is a problem with the stiffness of the connection box of the diesel generator set; 4) Determine whether there are problems with the structure and stiffness of the rotor of the generator by measuring the vibration speed of the body; 5) By measuring the vibration of the body, it is determined whether there are any problems with the rotor and the connection box.

2. The vibration test method for a single-bearing supported high-speed diesel generator set according to claim 1, characterized in that: In 1), when the vibration frequency of the body is measured to be the same as the rotor rotation frequency of the generator, and the amplitude of the body increases with the increase of the rotor rotation speed, and the amplitude of the isolator on one side of the isolator group is greater than the amplitude of the isolator on the other side, it is determined that the diesel engine and the generator are poorly matched.

3. The vibration test method for a single-bearing supported high-speed diesel generator set according to claim 1, characterized in that: In the above 2), when it is measured that at a certain rotation speed of the generator, all the vibration isolators of the vibration isolator group have a first-order amplitude increase in the vertical direction, it is determined that the main body and the vibration isolator group are poorly matched.

4. The vibration test method for a single-bearing supported high-speed diesel generator set according to claim 1, characterized in that: In the above 3), when it is measured that the first-order amplitude of the main body in the vertical direction increases at a certain rotation speed of the generator, it is determined that the main body is not matched with the vibration isolator group.

5. The vibration test method for a single-bearing supported high-speed diesel generator set according to claim 4, characterized in that: In the above 3), when it is measured that the first-order amplitude of the main body in the vertical direction increases at a certain rotation speed of the generator, it is determined that there is a problem with the vertical stiffness of the connection box.

6. The vibration test method for a single-bearing supported high-speed diesel generator set according to claim 1, characterized in that: In 4), when there is no first-order vibration in the vertical direction of the body at a certain rotation speed of the motor, and the measured vibration speed of the body in the vertical direction exceeds the standard range, it is determined that there are problems with the structure and torsional stiffness of the rotor.

7. The vibration test method for a single-bearing supported high-speed diesel generator set according to claim 1, characterized in that: In the above 5), when the measured lateral amplitude of the body exceeds the standard range, it is determined that there is a problem with the stiffness of the connection box.

8. The vibration test method for a single-bearing supported high-speed diesel generator set according to claim 7, characterized in that: In the above 5), when the measured lateral amplitude of the body exceeds the standard range, it is determined that there is a problem with the structure of the rotor.

9. The vibration test method for a single-bearing supported high-speed diesel generator set according to claim 1, characterized in that: In the above 5), when the longitudinal amplitude of the body is measured to be beyond the standard range, it is determined that there is a problem with the stiffness of the connection box.

10. The vibration test method for a single-bearing supported high-speed diesel generator set according to claim 9, characterized in that: In the above 5), when the longitudinal amplitude of the body is measured to be beyond a standard range, it is determined that there is a problem with the structure of the rotor.

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