Method for pre-selecting at least one spacer for an assembly subassembly

Abstract

The invention relates to a method for pre-selecting at least one spacer of an assembly sub-assembly, comprising the following steps: measuring individual components, which in an assembled state, form the assembly sub-assembly with at least one spacer; calculating a model of the assembly sub-assembly using the measurements obtained during the measurement of the individual components; and determining the dimensioning of at least one spacer on the basis of the calculated model and the permissible tolerances of the assembly sub-assembly.

Description

Title of the invention: Method for pre-selecting at least one spacer for an assembly subassembly

[0001] The present invention relates to a method for pre-selecting at least one spacer for a sub-assembly.

[0002] In modern manufacturing, the precise alignment and assembly of individual components to form a complete assembly subassembly play a central role. A commonly used manufacturing method employs spacers, such as spacer washers, to align these individual components in the desired position relative to one another. These spacers are selected and installed based on experience, which facilitates the assembly process but also presents challenges.

[0003] The assembly process begins by grouping the individual components to form a complete subassembly. Next, the dimensions and deviations within the subassembly are carefully measured. If the measured deviations or dimensions of the assembly subassembly or individual components fall outside the specified tolerance, the entire subassembly must be disassembled. Then, the spacers are replaced with parts of different dimensions, such as thinner or thicker spacer washers, and the subassembly is reassembled and measured again. This iterative process is continued until the desired deviations and dimensions are achieved.

[0004] A major drawback of this process is the high cost associated with the repeated assembly and disassembly of the subassembly. Each disassembly and reassembly also presents the risk of damaging individual components. Another problem is the documentation of the spacers used. Due to the frequent dimensional changes resulting from the iterative process, there is a high probability of errors that can lead to inaccuracies and other mistakes in the manufacturing process and in the traceable documentation.

[0005] The object of the present invention is to overcome, or at least mitigate, the drawbacks listed above. This is achieved by a method comprising all the steps of claim 1. Other advantageous configurations of the method according to the invention are found in the dependent claims.

[0006] The method according to the invention for pre-selecting at least one spacer of an assembly subassembly comprises the following steps: measuring individual components which, in an assembled state and with at least one spacer, form the assembly subassembly, calculation of a model of the assembly sub-assembly using measurements obtained during the measurement of individual components, and determination of the dimensioning of at least one spacer based on the calculated model and the permissible tolerances of the assembly sub-assembly.

[0007] Thus, before assembling the individual components to form the subassembly, a measurement step is performed, during which each individual component is measured. Based on the measurement results, a model of the assembly subassembly is calculated, using the measurements of the individual components obtained during the measurement process. A digital replica of the assembly subassembly is therefore created based on the measured individual components, so that in a subsequent step, the dimensioning of at least one spacer can be carried out using the calculated model. The dimensioning of at least one spacer is advantageously chosen so that the assembly subassembly calculated from the measured individual components falls within the specified tolerances.

[0008] Contrary to the conventional procedure, it is therefore no longer necessary to assemble (and possibly disassemble, if spacers of incorrect dimensions have been used) the individual components to determine whether a correct dimensioning of the spacers has been used, because the calculation of the assembly sub-assembly using the data of the individual components obtained from the measurement step already makes it possible to determine the concrete dimensioning of at least one spacer which will make it possible to obtain an assembly sub-assembly within the tolerances.

[0009] According to an advantageous improvement of the present invention, it may be provided that the method further includes the step of mounting the assembly sub-assembly with the individual measured components and at least one spacer whose dimension has been determined.

[0010] Thus, not only is the required dimensioning of at least one spacer determined, but the assembly sub-assembly is also assembled with the dimensioning calculated of at least one spacer based on this determination.

[0011] According to an optional modification of the present invention, it may be provided that the method further includes the step of recording the determined dimensioning and / or an identifier of at least one spacer in a file, preferably in a log file for the documentation of the parts used in the assembly sub-assembly.

[0012] Automated recording of the sizing determined for at least one spacer or of an identifier of at least one spacer used eliminates the probability of error typically encountered during manual recording and assembly of the subassembly based on empirical values. Indeed, It often happens that a subset of an assembly already assembled with a certain dimension of at least one spacer has to be disassembled and a spacer of a different dimension is used, so errors often occur when recording the type of spacer that was ultimately used.

[0013] According to an advantageous configuration of the present invention, it can be provided that at least one spacer can be selected from a multitude of dimensions scaled relative to each other, and that by determining the dimensioning, at least one spacer is selected in one of the scales.

[0014] The spacer to be inserted into the assembly sub-assembly can be used in a multitude of staggered dimensions during the assembly of the various individual components, the relative deviations of the individual components being able to differ depending on the choice of spacer dimensions and the tolerances of the individual components used. In order to accommodate the manufacturing tolerances of the respective individual components, it is often necessary to use a spacer specifically dimensioned for this purpose.

[0015] According to an optional modification of the present invention, it may be provided that the method further includes the step of verifying the measurements of the model calculated for compliance with the tolerances of the assembly sub-assembly, where, in the event of non-compliance with the tolerances, the individual components are checked and / or exchanged, and in the event of compliance with the tolerances, the dimensioning of at least one spacer is determined.

[0016] After calculating the assembly subassembly, it can be verified whether a calculated subassembly can actually meet the specified tolerances. If meeting the tolerances is not possible due to the dimensions of the individual measured components, this may lead to the replacement of one or more of the individual measured components. If, on the other hand, it is possible to obtain an assembly subassembly that falls within the specified tolerance with the individual measured components, the process is continued and at least one corresponding spacer is calculated.

[0017] According to an advantageous modification of the present invention, it may be provided that the process further includes the step of assembling the assembly sub-assembly by grouping the individual components and at least one spacer whose dimensions have been determined.

[0018] Furthermore, according to another advantageous improvement, it may be provided that the method further includes the step of selecting individual components, which, in an assembled state and with at least one spacer, form the assembly sub-assembly, for the measurement of the respective individual components.

[0019] For example, depending on several calculated assembly subsets, a combination of individual components or several combinations of components Individual components can be determined which, based on their actual dimensions and the available dimensions of the spacers, can form assembly subassemblies that fall within tolerances. Preferably, such a combination of individual components and / or spacers is chosen in such a way as to avoid, as much as possible, the rejection or non-use of any individual component. After measuring the respective individual components, a calculation is therefore performed so that the multitude of individual components can be used as much as possible in an assembly subassembly. This advantageously avoids a combination of individual components in an assembly subassembly that, without the calculation performed, would result in exceeding the specified tolerances of the assembly subassembly.In such a case, another individual component of appropriate (smaller) size is simply combined with the individual component (whose size is close to the upper acceptable tolerance range), so that during assembly, an assembly sub-assembly is created whose tolerances are met.

[0020] According to another improvement of the present invention, it may be provided that the method further includes the step of listing the individual components to be measured which are necessary to create the assembly sub-assembly.

[0021] Thus, based on the list, a parts holder can be loaded, which is then used by an optical measuring unit to measure the multitude of individual components inserted into the parts holder. Since the assembly subassembly may sometimes consist of complex subassemblies, the list of individual components is useful for loading such a parts holder.

[0022] According to another optional modification of the present invention, it may be provided that the method further comprises the measurement of a multitude of individual components, where a subgroup of the multitude of individual components, in a mounted state and with at least one spacer, creates the assembly subassembly, preferably where the multitude of individual components is sufficient to create several assembly subassemblies.

[0023] Thus, it can be envisaged that a multitude of individual components are first measured, from which several assembly subassemblies can be created. Based on the measurement results of the respective individual components, different combinations of individual components are then calculated for manufacturing an assembly subassembly. It can be envisaged that the multiple combinations of individual components for manufacturing the multiple assembly subassemblies are chosen in such a way that no assembly subassembly falls outside the specified tolerances. This leads to low rejection of individual components and corresponding cost savings.

[0024] According to an optional modification of the present invention, it may be provided that after a measurement of the individual components, several variants of assembly subsets are calculated using different individual components, and that the individual components are assigned to a specific assembly subset for which the calculated model of the specific assembly subset most closely approximates a dimensional specification.

[0025] Furthermore, it may be provided that, based on the measured individual components, all possible variants of assembly subsets are calculated. Thus, all possible variations of individual components that yield an assembly subset are calculated, and a final assignment of the individual components to one another is determined based on the results thus obtained.

[0026] According to another optional modification of the present invention, it may be provided that the dimensional specification is a tolerance range for the nominal dimensions of the assembly subassembly and / or a preferred dimensioning of at least one spacer, for example a specific thickness of a spacer washer.

[0027] Furthermore, according to an advantageous embodiment of the present invention, it may be provided that the spacer is a spacing element, for example a spacer washer.

[0028] It is known that a spacing element can exist in different increments (or thicknesses), which makes it possible to compensate for the respective tolerances of individual components when assembling different individual components, so that a subset of assembly is obtained whose overall tolerance is as much as possible decoupled from the tolerance of a respective individual component.

[0029] According to another optional modification of the present invention, the assembly subassembly may be provided to be an electro-hydraulic servo valve, preferably the individual components comprising at least one magnet, a lower pole piece and / or an upper pole piece.

[0030] In particular, for an electro-hydraulic servo valve (EHSV) used in aeronautical technology, for example, to precisely control aircraft control surfaces such as ailerons, elevators, and rudders, tolerances in the air gap area between the magnet and the rotor or between a magnet and an armature are critical, making the method described above particularly advantageous. This significantly increases the manufacturing time of an EHSV and improves the quality of documentation for the components actually installed, while reducing the rejection of individual components.

[0031] According to another modification of the present invention, it may be provided that the permissible tolerances of the assembly subassembly include or are a air gap between two individual components, in particular between a magnet and a rotor or armature.

[0032] Other features, details, and advantages of the invention will become apparent from the description in the following figures. These show: [Fig.1]: a schematic representation of an implementation of the process according to the invention. [Fig. 2]: a representation of a multitude of individual components during a measurement by an optical measuring unit, and [Fig.3]: a cross-sectional view of an EHSV as an realization of a sub-assembly constructed from several individual components.

[0033] Figure 1 shows a possible execution of the process according to the invention, where, after selecting a specific program for an assembly subassembly, a parts holder is loaded according to the specifications of a machine performing the process. Depending on the program selected for a specific assembly subassembly, the required individual components are placed in a parts holder, in which the measurement of the dimensions of the respective individual components can also take place. The specification of the individual components to be measured prevents any erroneous deviation of the individual components required for the assembly subassembly.

[0034] Next, the part support can be inserted into the machine performing the process, which also includes the transfer of individual components into a detection zone of an optical measuring unit.

[0035] The process then begins by optically measuring the dimensions of each individual component. After obtaining the measurements for each of the individual components, a calculation is performed to create a virtual assembly subset, using the measured values ​​of the respective individual components for the dimensions of the virtual assembly subset. The calculation still has one degree of freedom regarding the dimensioning of at least one spacer, the dimensioning of the spacer being chosen so that the tolerances of the assembly subset are neither exceeded nor under-exceeded.

[0036] Next, a check of the calculated dimensions of the assembly subassembly is performed to ensure compliance with and accuracy of the tolerances. If the tolerances are exceeded, an error signal is generated, and the individual components are checked or replaced. Appropriate dimensions for the spacers to be installed in the assembly subassembly are selected to ensure that the tolerances are neither exceeded nor under-exceeded. A variety of spacer dimensions can be used for this purpose; the method is designed to use such a dimension for each respective spacer that the tolerances of the assembly subassembly are maintained.

[0037] If, on the other hand, the verification is successful, that is to say that there is no exceeding or under-exceeding of the permissible tolerances in the calculated assembly sub-assembly, for example with regard to a relative deviation between two individual components arranged with respect to each other in the assembly sub-assembly or the external dimensions of the assembly sub-assembly, the method according to the invention is continued.

[0038] Subsequently, documentation concerning the sizing or measurements of the spacers used in the calculated model is implemented, so that documentation of the installed components is also created with regard to the spacers used.

[0039] Finally, at least one assembly subset is mounted with at least one calculated spacer and the individual components assigned to a respective assembly subset.

[0040] Figure 2 shows a representation of a multitude of individual components during a measurement by an optical measuring unit.

[0041] The optical measuring unit is designated in the representation as an optical profilometer and is capable of determining the dimensions of the respective individual components arranged on a support plate. Each individual component arranged on the support plate is measured separately. To facilitate the insertion of the support plate into the optical profilometer, the support plate may have one or more handles.

[0042] Figure 3 shows a cross-sectional view of an EHSV (an electro-hydraulic servo valve) as an example of an assembly subassembly. It can be seen that the assembly subassembly consists of several individual components which, via spacers, for example adjusting washers, occupy their respective positions within the assembly subassembly. If, for example, the thickness of an adjusting washer (also called a spacer washer) is changed, the corresponding air gap of a lower pole piece relative to an armature changes.

[0043] By measuring the individual components and calculating the measurements in the calculated assembly subassembly relative to each other, the correct dimensions of the spacers are installed on the first attempt. Disassembly, as was previously common with the prior art method, is therefore no longer necessary, as the incorrect use of spacers of the wrong dimensions no longer occurs. Furthermore, deviations from tolerances are detected during the calculation of the individual components before assembly, thus avoiding unnecessary work steps. In addition, documentation of the spacers is performed automatically, so that transcription errors are eliminated, errors that often occurred previously due to frequent changes of spacers. Finally, the The process according to the invention increases the safety of the process and reduces assembly time.

Claims

Demands

1. A method for pre-selecting at least one spacer of an assembly subassembly, comprising the following steps: measuring individual components, which in an assembled state, form the assembly subassembly with at least one spacer; calculating a model of the assembly subassembly using the measurements obtained during the measurement of the individual components; and determining the dimensioning of at least one spacer on the basis of the calculated model and the allowable tolerances of the assembly subassembly.

2. Method according to claim 1, further comprising the following step: assembly of the sub-assembly with the individual measured components and at least one spacer whose dimension has been determined.

3. A method according to any one of the preceding claims, further comprising the following step: recording the determined dimensioning and / or an identifier of at least one spacer in a file, preferably in a log file for documenting the parts used in the assembly subassembly.

4. A method according to any one of the preceding claims, wherein at least one spacer can be selected from a multitude of dimensions scaled relative to one another, and by determining the dimensioning, at least one spacer is selected from one of the scales.

5. A method according to any one of the preceding claims, further comprising the following step: verification of the measurements of the model calculated for compliance with the tolerances of the assembly sub-assembly, wherein in the event of non-compliance with the tolerances, the individual components are checked and / or exchanged, and in the event of compliance with the tolerances, the dimensioning of at least one spacer is determined.

6. A method according to any one of the preceding claims, further comprising the following step: assembly of the sub-assembly by grouping the individual components and at least one spacer whose dimensions have been determined.

7. A method according to any one of the preceding claims, wherein prior to measuring the individual components, the following step is performed: selection of individual components, which, in an assembled state and with at least one spacer, form the assembly subassembly, for measuring the respective individual components.

8. A method according to any one of the preceding claims, further comprising the following step: listing the individual components to be measured that are necessary to create the assembly subassembly.

9. A method according to any one of the preceding claims, further comprising the following step: measuring a multitude of individual components, wherein a subgroup of the multitude of individual components, in an assembled state and with at least one spacer, creates the assembly subassembly, preferably in which the multitude of individual components is sufficient to create several assembly subassemblies.

10. A method according to claim 9, wherein, after measuring the individual components, several variants of assembly subsets are calculated using different individual components, and the individual components are assigned to a specific assembly subset for which the calculated model of the specific assembly subset most closely approximates a dimensional specification.

11. 11. A method according to claim 10, wherein, on the basis of the individual components measured, all possible variants of assembly sub-assemblies are calculated.

12. A method according to any one of claims 10 or 11, wherein the dimensional specification is a tolerance range for the nominal dimensions of the assembly subassembly and / or a preferred dimensioning of at least one spacer.

13. A method according to any one of the preceding claims, wherein the spacer is a spacer element, for example a spacer washer.

14. A method according to any one of the preceding claims, wherein the assembly subassembly is an electrohydraulic servo valve, preferably the individual components comprising at least one magnet, a lower pole piece and / or an upper pole piece.

15. A method according to any one of the preceding claims, wherein the allowable tolerances of the assembly subassembly include or are an air gap between two individual components, in particular between a magnet and a rotor or armature.

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