A bearing preloading method

Abstract

The present invention relates to a method (100) which enables the preloading of bearings, directly affecting the service life, efficiency and noise of the bearings included in gearboxes used as power transmission systems in vehicles, to be carried out practically under technically accurate and mass production conditions.

Description

[0001] DESCRIPTION

[0002] A BEARING PRELOADING METHOD

[0003] Technical Field

[0004] The present invention relates to a method which enables the preloading of bearings, directly affecting the service life, efficiency and noise of the bearings included in gearboxes used as power transmission systems in vehicles, to be carried out practically under technically accurate and mass production conditions.

[0005] Background of the Invention

[0006] Some of the types of bearings included in gearboxes are fitted with a certain amount of preload during assembly in order to be improved in terms of service life, durability, efficiency and noise. The part that provides the preload is often the shims that are inserted behind the bearing. The dimensions of the shims are determined based on the final dimensions of the manufactured gear, shaft, bearing and casing parts that constitute the gearbox. According to these dimensions, the correct shim for the optimum bearing preload must be fitted into the correct case.

[0007] Shim selection and bearing preloading can be performed by different methods. In one of these methods, each part that will determine the shim dimension is measured individually after manufacturing, then the shim can be selected according to these measurements, and the gearbox can be assembled in this way. In another method, the gear and shaft dimensions are not measured as they will be precise, only the manufactured casing dimensions and bearings can be taken into account, and the assembly can be carried out. Alternatively, in another method, it can be done by using precision tolerance bearings and measuring only the casing without measuring the bearing, gear and shaft. In all these methods, the gear, shaft, bearing and casing parts that affect the determination of the shim dimension are measured individually after manufacturing and the shim dimension is calculated by taking these values into account. However, the need to measure each part individually and to establish high precision tolerances for each part causes difficulties in the manufacturing and assembly process. For this reason, there is a need for a method which facilitates the calculation of the shim dimension needed during bearing preloading.

[0008] The Japanese patent document no. JP2011095064, an application included in the state of the art, discloses a bearing preloading system. The invention subject to the said Japanese patent document provides a preload measurement method for measuring preload applied to a bearing with superior accuracy by a simple method. The solution is a method for measuring a preload to be applied to bearings 6 and 8 in a transmission unit that applies a preload in the axial direction to each of the bearings. This method comprises injecting the shim 12 on the right-side in the radial direction with respect to the mounting case 9 into a gap formed between the bearing holding part 7 and the bearing 8 on the right-side, in a situation where a ring gear 3 is engaged with a drive pinion 4. The method comprises using an axial force calculation device 23 for measuring the thrust force required to inject the right-side shim 12 in the radial direction with respect to the mounting case 9 into a gap formed in the axial direction between the bearing holding part 7 and the right-side bearing 8, and for calculating the axial force Fs (preload) based on the thrust force f measured by the thrust force measuring device 22.

[0009] Summary of the Invention

[0010] An object of the present invention is to realize a method which enables the preloading of bearings, directly affecting the service life, efficiency and noise of the bearings included in gearboxes used as power transmission systems in vehicles, to be carried out practically under technically accurate and mass production conditions. Detailed Description of the Invention

[0011] “A Bearing Preloading Method” realized to fulfil the objectives of the present invention is shown in the figure attached, in which:

[0012] Figure 1 is the flow chart relating to the inventive method.

[0013] Figure l is a view comprising the parts in the bearing preloading mentioned in the inventive method.

[0014] Figure 3 is a detailed view relating to the shim mentioned in the inventive method.

[0015] 100. Method

[0016] A: Gear & shaft

[0017] B: First bearing

[0018] C: Second bearing

[0019] D: First casing

[0020] E: Second casing

[0021] F: Shim

[0022] The inventive method (100) which enables the preloading of bearings, directly affecting the service life, efficiency and noise of the bearings included in gearboxes used as power transmission systems in vehicles, to be carried out practically under technically accurate and mass production conditions comprises the steps of: carrying out sub-assembly of gear & shaft (A), bearings (B, C) and casings (D, E) that are effective in calculating the shim (F) dimension used during bearing preloading (101); and determining the dimension of the shim to be fitted into the bearing by measuring the distances between the junction of the casings (D, E) and the outer surfaces of the bearings (B, C) after sub-assembly and then by calculating the difference between them (102).

[0023] In the step of carrying out sub-assembly of gear & shaft (A), bearings (B, C) and casings (D, E) that are effective in calculating the shim (F) dimension used during bearing preloading (101) of the inventive method (100), the first bearing (B) is placed on one side and the second bearing (C) is placed on the other side of the gear & shaft (A) used for power transmission. The second bearing (C) is placed in the second casing (E) so that the second bearing (C) and the second casing (E) are in contact with each other and the sub-assembly is completed and the measurement processes are started.

[0024] In the step of determining the dimension of the shim to be fitted into the bearing by measuring the distances between the junction of the casings (D, E) and the outer surfaces of the bearings (B, C) after sub-assembly and then by calculating the difference between them (102) of the inventive method (100), a measurement is carried out from the surface of the second casing (E) to the surface of the first bearing (B) after sub-assembly is performed and the measurement is recorded as the DI value. The distance from the bearing seating surface to the joining surface of the first casing (D) is measured and the measurement is recorded as the D2 value. The optimum shim (F) dimension to be used is calculated by calculating the difference between the DI and D2 measurements. The shim (F) of the calculated dimension is placed in the bearing carrier of the first casing (D) and the bearing preloading is completed by closing the gearbox by joining the first casing (D) with the first bearing (B) of the structure that is sub-assembled.

[0025] Industrial Application of the Invention

[0026] In the inventive method (100), in order to determine the correct shim (F) dimension, the dimensions of all gear & shaft (A), bearing (B, C) and casing (D, E) parts that may affect the dimension are evaluated after manufacturing. Unlike previous techniques, this evaluation is not based on the individual dimensions, but on the dimensions during the sub-assembly stage. After the bearings (B, C), gears & shafts (A) are joined, each shaft assembly is inserted into one of the casings. The dimension from the casing joining surface to the bearing surface that remains outside (DI) is measured (it is more favourable to measure under a certain load in order to obtain bearing gaps). The dimension from the joining surface to the bearing seating surface (D2) of the other idle casing, which is waiting to be assembled, is also measured. With these two obtained measurements, the required shim (F) dimension is calculated and the idle casing is placed in the bearing carrier and the assembly is completed.

[0027] Within these basic concepts; it is possible to develop various embodiments of the inventive “A Bearing Preloading Method (100)”; the invention cannot be limited to examples disclosed herein and it is essentially according to claims.

Claims

CLAIMS1. The inventive method (100) which enables the preloading of bearings, directly affecting the service life, efficiency and noise of the bearings included in gearboxes used as power transmission systems in vehicles, to be carried out practically under technically accurate and mass production conditions characterized in that it comprises the steps of carrying out sub-assembly of gear & shaft (A), bearings (B, C) and casings (D, E) that are effective in calculating the shim (F) dimension used during bearing preloading (101); and determining the dimension of the shim to be fitted into the bearing by measuring the distances between the junction of the casings (D, E) and the outer surfaces of the bearings (B, C) after sub-assembly and then by calculating the difference between them (102).

2. A method (100) according to Claim 1; characterized in that in the step of carrying out sub-assembly of gear & shaft (A), bearings (B, C) and casings (D, E) that are effective in calculating the shim (F) dimension used during bearing preloading (101), the first bearing (B) is placed on one side and the second bearing (C) is placed on the other side of the gear & shaft (A) used for power transmission.

3. A method (100) according to Claim 1 or 2; characterized in that in the step of carrying out sub-assembly of gear & shaft (A), bearings (B, C) and casings (D, E) that are effective in calculating the shim (F) dimension used during bearing preloading (101), the second bearing (C) is placed in the second casing (E) so that the second bearing (C) and the second casing (E) are in contact with each other and the sub-assembly is completed and the measurement processes are started.

4. A method (100) according to any one of the preceding claims; characterized in that in the step of determining the dimension of the shim to be fitted into the bearing by measuring the distances between the junction of the casings (D, E) and the outersurfaces of the bearings (B, C) after sub-assembly and then by calculating the difference between them (102), a measurement is carried out from the surface of the second casing (E) to the surface of the first bearing (B) after sub-assembly is performed and the measurement is recorded as the DI value.

5. A method (100) according to any one of the preceding claims; characterized in that in the step of determining the dimension of the shim to be fitted into the bearing by measuring the distances between the junction of the casings (D, E) and the outer surfaces of the bearings (B, C) after sub-assembly and then by calculating the difference between them (102), the distance from the bearing seating surface to the joining surface of the first casing (D) is measured and the measurement is recorded as the D2 value.

6. A method (100) according to any one of the preceding claims; characterized in that in the step of determining the dimension of the shim to be fitted into the bearing by measuring the distances between the junction of the casings (D, E) and the outer surfaces of the bearings (B, C) after sub-assembly and then by calculating the difference between them (102), the optimum shim (F) dimension to be used is calculated by calculating the difference between the DI and D2 measurements.

7. A method (100) according to any one of the preceding claims; characterized in that in the step of determining the dimension of the shim to be fitted into the bearing by measuring the distances between the junction of the casings (D, E) and the outer surfaces of the bearings (B, C) after sub-assembly and then by calculating the difference between them (102), the shim (F) of the calculated dimension is placed in the bearing carrier of the first casing (D) and the bearing preloading is completed by closing the gearbox by joining the first casing (D) with the first bearing (B) of the structure that is sub-assembled.

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