Yoke shaft

Abstract

The invention relates to a yoke shaft (1) which is one of the individual components composing a driveshaft (9) and is obtained through the friction welding method.

Description

[0001] YOKE SHAFT

[0002] Field of the Invention

[0003] The invention relates to a yoke shaft which is one of the individual components composing a driveshaft and is obtained through the friction welding method.

[0004] State of the Art

[0005] Yoke shaft (1) is centrically assembled and works in cooperation alongside its conjugate component tube sleeve (2) thanks to its spline form (3). The yoke shaft (1) and the tube sleeve (2) reciprocate on the axial direction thanks to their spline form (3). Said reciprocation is provided in Figure 1. This movement is known as the sliding movement and the amount of movement varies depending on the design and area of usage of the motor vehicle. The magnitude and therefore sizes of the mating surfaces of the spline forms (3) of the yoke shaft (1) and the tube sleeve (2) is determined based on the amount of sliding movement.

[0006] Yoke shaft (1) is obtained with the combination two components through the friction welding method, one of the components being the yoke component (4), and the other being the cylindrical bar (5). Figure 2 provides the sectional view of the friction welded yoke shaft’s (1) components (before welding). During the friction welding process, yoke component (4) and cylindrical bar (5) are attached to the bench by jaws (7) through the clamping surfaces (6) shown in Figure 3. As wall thickness (t) increases, the axial pressure value (P) required to be applied to the yoke component (4) and cylindrical bar (5) by the bench is also increased (Table 1).

[0007] Table 1. Correlation between wall thickness (t) and bench pressure (P). The increase of pressure applied from the bench to the component (P2) necessitates the increase of the clamping surfaces (6) of the yoke component (4) and the cylindrical bar (5). Otherwise, the said components slide from under the jaws (7) and / or leaves jaw-marks on the clamping surfaces (6) during the friction welding. When the fact that the total length of the yoke shaft (1) being constant is taken into consideration, the more that the clamping surfaces (6) are extended, the shorter that the length of the spline form (3) of the yoke shaft (1) obtained after the welding will get. However, clamping surfaces (6) are desired to have the optimum length (neither short nor long). This situation (the spline form (3) of the yoke shaft (1) being shortened) manifests itself as a problem.

[0008] In the prior art, to avoid shortening the spline form (3), the yoke component (4) is supported with the support bar (8) positioned into the ear holes of the yoke component (4) alongside the jaws (7) as described in Figure 4 to prevent unwanted movement.

[0009] In the patent search in the state of the art, patent applications with publication numbers US2014018178 A1 and US6105849 A are found. In the patent application with the publication number US2014018178 A1 , the shortening amount during the friction welding is defined as “U”. However, no data relating to its calculations are shared. In the patent application with the publication number US6105849 A, the form of the flash which emerges during the welding being changed is explained and the impact of operation parameters such as pressure, speed on the form of the flash is addressed. However, the calculating of the optimum apparatus clamping surfaces and the obtaining of yoke component by welding the yoke component and the cylindrical bar that have this property are not mentioned in said documents.

[0010] Brief Description of the Invention

[0011] The present invention relates to a yoke shaft that meets said requirements, eliminates all disadvantages and brings some additional advantages.

[0012] The object of the invention is to solve said disadvantages by being inspired from the current situations. The main object of the invention is to obtain friction welded yoke shaft having optimum geometry. In the invention, the clamping surfaces are calculated to have the optimum length as a solution to the problem in the state of the art, so that clamping surfaces are decreased as much as possible which decreases the loss emerging on the size of the spline form mating surfaces. The use of support bars supporting the yoke component ears are not required. Consequently, friction welded yoke shaft having optimum geometry is obtained. The yoke shaft and support bar used in the invention are manufactured from tempered steel.

[0013] The following figures and their detailed descriptions will make the invention’s structural and characteristic features and its advantages easier to understand. Therefore, the assessment should be made while considering the figure and their detailed descriptions.

[0014] Figures for a Better Understanding of the Invention

[0015] Figure 1 provides the axial reciprocation movement of the yoke shaft and the tube sleeve components thanks to their spline form.

[0016] Figure 2 provides the sectional view of the friction welded yoke shaft’s components before welding.

[0017] Figure 3 provides the apparatus clamping surfaces on the yoke component and cylindrical bar before welding.

[0018] Figure 4 provides the apparatus clamping surfaces on the yoke component and cylindrical bar and the support bar positioned into the ear hole before welding.

[0019] Figure 5 provides the sectional view of the yoke component and cylindrical bar before welding.

[0020] Figure 6 provides the sectional view of the yoke component and cylindrical bar after welding. Figure 7 provides the view of the sectioned yoke shaft and tube sleeve on the driveshaft.

[0021] Descriptions of Part References

[0022] 1 Yoke shaft

[0023] 2 Tube sleeve

[0024] 3 Spline form

[0025] 4 Yoke component

[0026] 5 Cylindrical bar

[0027] 6 Clamping surface

[0028] 7 Jaw

[0029] 8 Support bar

[0030] 9 Driveshaft t Wall thickness

[0031] Lu Clamping surface length on the cylindrical bar side

[0032] Ly Clamping surface length on the yoke component side ju Width of the jaw gripping the cylindrical bar jy Width of the jaw gripping the yoke component

[0033] Detailed Description of the Invention

[0034] In this detailed description, preferred embodiments of the invention are described solely for a better understanding of the subject matter.

[0035] The invention relates to a yoke shaft (1) which is one of the individual components composing a driveshaft (9) and is obtained through the friction welding method. The said yoke shaft (1) comprises one yoke component (4) and one cylindrical bar (5). Said yoke component (4) and cylindrical bar (5) having wall thickness (t) and is a hollow structure. Yoke component (4) and cylindrical bar (5) are welded with the friction welding method to form the yoke shaft (1). In the structure of the yoke shaft (1), at least one jaw (7) is used to secure the yoke component (4) and cylindrical bar (5) on the welding bench. Figure 5 provides the sectional view (before welding) belonging to the yoke component (4) and cylindrical bar (5). According to this, clamping surface lengths where the jaws (7) are gripping components having walls at the wall thickness (t); clamping surface length on the cylindrical bar’s side (Lu) and clamping surface length on the yoke component’s side (Ly) are provided. Likewise, the width of the jaw gripping the cylindrical bar (ju) and the width of the jaw gripping the yoke component (jy) are shown on the figure.

[0036] The length of the clamping surface on the cylindrical bar’s side (Lu) is the length of the surface that the jaws (7) which are used with the purpose of fixing the component to the bench during the friction welding operation are gripping the component from.

[0037] The length of the clamping surface on the yoke component’s side (Ly) is the length of the surface that the jaws which are used with the purpose of fixing the component to the bench during the friction welding operation are gripping the component from.

[0038] In the friction welded yoke shaft (1) having optimum geometry:

[0039] 1 . The inner and outer diameters of the yoke component (4) and cylindrical bar (5) are processed in a way that their walls have the same thickness. The purpose behind this is to keep the wall thickness of the components to be welded as equal to keep the amount of shortening that may take place after the welding numerically under control.

[0040] 2. The clamping surface length on the yoke component’s side (Ly) is determined with the equation below.

[0041] L = f (k, s") + Jy

[0042] Here, f(k,c) is a function that provides the total value of the shortening amount emerging on the clamping surface length during welding (expressed with k) and the flash size (expressed with c) emerging with it.

[0043] 3. The clamping surface length on the bar’s side (Ly) is determined with the equation below. The f(k,c) value expressed in the equations defined in the articles 2 and 3 above is determined by using the equation below depending on the wall thickness (t). The equation is an equation obtained by analyzing the shortening that takes place after welding the pairs of cylindrical bar (5) and yoke component (4) for different wall thickness (t). The said equation is used for yoke component (4) having a wall thickness (t) in the range of 11 to 14 mm. f(k,c) = 0.9t2- 20.5t + 126.4

Claims

CLAIMS1. A yoke shaft (1), which provides freedom of movement to a driveshaft by reciprocating axial movement within conjugate component, comprising:• a yoke component (4)• a cylindrical bar (5) combined with the yoke component (4) through friction welding method, characterized in that• the yoke shaft (1) comprises spline form (3), which is formed at the end, provides ability to reciprocate axial movement,• end of the cylindrical bar (5) with the spline form (3) is hollow and having wall thickness (t),• end of the yoke component (4) is hollow and having wall thickness (t),2. The yoke shaft (1) according to claim 1 , characterized by comprising clamping surface (6) gripped by at least one jaw (7) to ensure optimum geometry.

3. The yoke shaft (1) according to any of the preceding claims, characterized in that clamping surface length on the yoke component side (Ly) and width of the jaw gripping the yoke component (jy) have a correlation of Ly = f(k,c) + jy.

4. The yoke shaft (1) according to any of the preceding claims, characterized in that clamping surface length on the cylindrical bar side (Lu) and width of the jaw gripping the cylindrical bar (ju) have a correlation of Lu f(k,c) + ju.

5. The yoke shaft (1) according to any of the preceding claims, characterized in that f(k,c)’s function depending on the wall thickness (t) is f(k,c) = 0.9t2- 20.5t + 126.4.

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