WHEEL BOLT EMBODIMENT HAVING SQUARE CROSS-SECTION PROFILE

Technical Field

The invention relates to wheel bolts used in heavy vehicles as connection component.

The invention particularly relates to a wheel bolt embodiment lighter than the similar ones, enabling post dismantling re-use of wheel bolts installed into hub holes in order to enable long life of wheel bolts manufactured with high costs by use of square section profile formed on the hubs of the wheel bolts used in heavy duty vehicles without any additional costs.

Background of the Related Art

Figure 1 shows a standard wheel bolt used currently. Wheel bolts are the parts particularly used in wheel connections of heavy vehicles. One side of head of the present wheel bolt is manufactured as inclined plane in order to finish fitting. The diameter of the wheel bolt body is considerably smaller when compared to head. The force fitting section of the body is formed by means of grinding. Force fitting section is the part having the biggest diameter on the body. A groove is formed on the joint of head and body.

In addition, a passage radius is formed on the joint of head and body again in order to provide collapse of hole and wheel bolt fully and contact thereof. The diameter of the force fitting section is greater than hole diameter. The threaded part and force fitting section of the wheel bolts join. Outer diameter of the thread is smaller than outer diameter of force fitting section.

Two different diameters are formed at body part to produce wheel bolt. The part having greater diameter is ground to obtain force fitting section. Thread is formed on the part having smaller diameter. A conical passage is obtained between those two parts. Such wheel bolts have some disadvantages. Force fitting section must be ground in order to provide the required tolerances.

If the hole where the wheel bolt is located does not have countersink, the part where head and force fitting section join must be grooved. The grooving operation increases cost together with grinding since it is made by machining. The weight of the raw material used as product and for production is more than the weight of the raw material of the product. An additional effort is required to coincidence of hub hole and wheel bolt axis after installation of the wheel bolt into the hub hole.

In this context, since the diameter of force fitting section is greater than diameter of hub, there is risk of deformation during installation. The wheel bolt does not have a part providing such centralization. The force fitting section frequently stucks to the hub hole during re-assemblings and for that reason, more force is applied, which causes damage to wheel bolt and hole and leads to the conclusion that it cannot be used anymore.

There are various wheel bolts having triangle sectioned knurls instead of ground surface. In order to prevent twisting during installation of the wheel bolt, the knurls should be parallel to wheel bolt axis. However, such connection members cannot be re-used. These are the biggest disadvantages. Knurls on the wheel bolt are subject to plastic deformation during installation, and required tolerances are lost. Therefore, re-use of the wheel bolts are not possible. The same case is also true for the hole.

In conclusion, with the square section profile formed on the force fitting section of the wheel bolt used in heavy vehicles eliminating the above mentioned unfavorable issues and disadvantages, it is needed to manufacture a wheel bolt providing long use of wheel bolts produced with high costs, enabling re-use of the wheel bolts installed into hub holes after dismantling without any additional cost for user, and lighter than similar products, and the fact that current solutions are inadequate has required development in the related art.

Brief Description of the Invention

According to the present invention, force fitting section of the wheel bolt has a square sectioned threaded profile having multi-ends, preferably angular end,

parallel to wheel bolt axis. The said square section thread profile contacts at least 30% of the cylindrical area of the hub hole. This square section profile is formed by means of cold forming process. In this case, the invention aims to perform the same function based on the idea of elimination of ground force fitting section. Angular ends of the square sectioned profile are located on point basis around the force fitting section. While installing the wheel bolt into the hub hole, contact between cylindrical surface area and angular ends is provided. Thus the wheel bolt is centralized into and centralized onto the hole. With application of following axial force, the positioning is made in a controlled way, and no plastic deformation occurs. No additional location assistance is needed during location of square sectioned profile wheel bolt into the hub hole.

The hub hole does not radial expand in whole. Square sectioned profile causes partial expansion in linear way. Hub hole undergoes an elastic deformation according to the form of square sectioned profile. Since the deformation is elastic, loosing in hub hole material occurring in the spaces between square sectioned profiles after completion of force fitting section action.

Also an axial fitting occurs between square sectioned profile and hub hole. Additionally, friction fitting occurs on contact surfaces. Since the strength of the wheel bolt is greater than the strength of the hub, hub material undergoes an elastic deformation.

Force fitting section has at least 30% contact area. This area is the area of the parts of the square sectioned profile contacting hub hole inner surface. The percentage of contact area is associated with cylindrical surface area of hub hole. (Provided that force fitting section and hole length are the same) the fact that 30% of contact area provides the holding force provided by the wheel bolt having a ground force fitting section area is surprisingly adequate. The reason behind it is the fitting in elastic area. The square sectioned profile on force fitting section area is manufactured by means of cold forming simultaneously with the wheel bolt without need for a second operation. Therefore, it is manufactured with less cost without need for additional operation and is more strong when compared to other cross-sectioned knurls. Consumption of raw material is less. Due to less part unit

weight, it also decreases the weight of the vehicle where it is used. Considerable decrease in contact area decreases blockings that might occur during installation of wheel bolt into hub hole. Outer diameter of square cross-sectioned profile should be bigger that outer diameter of ground cylindrical force fitting section.

When inner surface of the hub hole is taken into consideration, outer diameter of ground surface is bigger. The entire ground area is in contact with inner surface of hub hole. The contact area of the wheel bolt that is being subject of the invention and has a square cross-sectioned force fitting section is between 30%-40%. A measurement size in a higher level is used for the wheel bolt being subject of this invention. Since the deformation occurs in elastic area, no damage occurs on either wheel bolt or hub hole.

Flank angle of the square cross-sectioned profile is between 0 and 30 degrees and preferably 15 degree. The purpose of designing such a flank design which can be deemed as perpendicular is to provide spreading of material changing place into a bigger diameter and thus to provide required contact area. The depth of the square cross-sectioned profile should not be too big. Bringing the square cross- sectioned profile into size of outer diameter is highly important. Upon formation of square cross-sectioned profile by use of cold shaping method, the outer diameter is brought to required size in adequate smoothness and parallel without need for a second operation or grinding operation. Thus, fatigue strength during fastening of the wheel bolt and the abrasion strength are increased and a strong wheel bolt is obtained.

The round steel bar which the wheel bolt will be manufactured of has one single diameter along the shank. The outer diameter of the helix, that is, the area which has screwing threads, is smaller than the outer diameter of the square section profile. Thus, installation of wheel bolt into hub hole is provided without damage to screwing threads. Lower tooth diameter of square cross-sectioned profile is bigger than diameter of area circle of the screwing threads, and this prevents any probable breaking in the areas where the threads are located.

In order to achieve the said purposes, a wheel bolt used in wheel connections of heavy vehicles, consisting of head, force fitting section, body and a part having fixing part containing threads has been developed, and it is characterized in that it consists of square cross-sectioned profile formed on the said force fitting section means of cold shaping in a manner providing knurls in form of projections thereon.

The structural and characteristic features as well as all advantages of the invention will be more clearly understood referring to the below figures and detailed descriptions referring to the said figures and therefore, during assessment, the said figures and detailed descriptions should be taken into consideration.

Description of Figures

Figure 1 : Side view of a standard wheel bolt used currently.

Figure 2: Side view of the wheel bolt being subject of the invention indicating installation into hub hole.

Figure 3: Side and upper view of the wheel bolt being subject of the invention.

Figure 4: The view indicating detail A given in Figure 3.

Reference Numbers

1. Wheel bolt 25. Body

2. Mounting part 26. Lower surface of head

3. Hub hole 27. Mounting part surface

4. Head 28. Axial force

5. Body 29. Axis

6. Lower surface of the head 30. Force fitting section

7. Mounting part surface 31. Square section profile

8. Axial force 32. Knurl

9. Axis 33. Circular cavity

10. Force fitting section 34. Outer diameter of square section profile

11. Outer diameter of force fitting 35. Angular end section

12. Circular transition area 36. Conical area

13. Conical part 37. Transition area

14. Outer diameter of body 38. Outer diameter of body

15. Fixing part 39. Fixing area

16. Thread 40. Thread

17. Outer diameter 41. Outer diameter

18. Inner diameter 42. Inner diameter

19. Fixing area 43. Fixing area

20. Fixing area 44. Fixing area

21. Wheel bolt 45. Contact surface

22. Mounting part 46. Outer top of knurl

23. Hub hole 47. Outer bottom of knurl

24. Head 48. Flank angle

Detailed Description of the Invention

Figure 1 shows side view of a standard wheel bolt used currently. As it can be seen from the figure, the wheel bolt (1 ) is positioned into hub hole (3) formed on

mounting part (2). The wheel bolt (1) is inserted into hub hole (3) by means of an axial force (8). The wheel bolt (1 ) consists of two parts, namely, head (4) and body (5). Head (4) is the part of the wheel bolt (1 ) having the biggest diameter. Lower surface of the head (6) is directed to the body (5). When the wheel bolt (1 ) is positioned into mounting part (2) by means of axial force (8), bottom surface of head (6) sits on the mounting part surface (7). The head (4) and body (5) is axially in alignment on axis (9).

The current wheel bolts (1 ) have a part called force fitting section (10) on the body (5). The outer diameter (11) of the force fitting section obtained by means of grinding of the force fitting section (10) is in contact with cylindrical inner surface of hub hole (3). Outer diameter (11) and circular transition area (12) of the force fitting section (10) obtained by means of grinding can only be formed by use of machining method. During the initial stage of the mounting process, a conical part (13) on the body (5) helps positioning the wheel bolt (1 ) into mounting part (2). The body (5) has an outer diameter (14) smaller than outer diameter of force fitting section (11 ).

In order to connect the wheel bolt (1 ) to an area, a fixing area (15) is formed whereon threads (16) are provided in lower part of the body (5). Maximum outer diameter (17) of the fixing part (15) is always smaller than outer diameter (11 ) of force fitting section obtained by means of grinding. In addition, outer diameter (17) of fixing part (15) is also smaller than inner diameter of hub hole (3). But outer diameter (17) of fixing part (15) is smaller than outer diameter (11 ) of force fitting section. The inner diameter of threads (16) formed on fixing part (15) is formed in a manner smaller than outer diameter of the body (14).

Side surface of the head (4) has a fixing area (19). In order to prevent twisting of the wheel bolt (1 ) locked, a fixing area (20) is formed on the mounting part (2) in a manner connecting to fixing area (19) formed on the head (4).

Figure 2 shows side view of the wheel bolt (21 ) being subject of the invention indicating installation into hub hole (23).The wheel bolt (21 ) is inserted into hub hole (23) in the mounting part (22) by means of an axial force (28). The wheel bolt

(21) being subject of this invention consists of two parts, namely, one head (24) and one body (25). Head (24) is the part of wheel bolt (21 ) having the biggest diameter. Lower surface of the head (26) is directed towards the body (25). When the lower surface of the head (26) is inserted into mounting part (22) by help of axial force (28), it sits on mounting part surface (27). Head (24) and body (25) are in alignment axially on the axis (29). Multi-ends square sectioned profile (31 ) is formed on the force fitting section (30) of the wheel bolt (21 ) being subject of this invention by use of cold shaping method as a feature different from the related art. Square section profile (31 ) has knurls (32) independent from each other, having equal inclination and formed in equal intervals parallel to the axis.

With help of the circular cavity (33) formed on the head (24) of the wheel bolt (21 ), it is not needed to form grooves into the hub hole (23) on the mounting part (22). In addition, when axial force (28) is applied to the wheel bolt (21 ), collection of coating and dirt from the wheel bolt (21 ) in the circular cavity (33) is provided. With help of the circular cavity (33) formed on the head (24), full sitting of lower surface of the head (26) onto mounting part surface (27) is provided as a result of the axial force (28) applied to the wheel bolt (21).

During formation of square section profile (31) on the force fitting section (30) by use of cold shaping method, the angular ends (35) are formed by use of the same method. The said angular ends (35) help positioning of wheel bolt (21 ) into mounting part (22) during the initial stage of the mounting process. In addition, a conical area (36) is provided between lower part of the square section profile (31 ) formed on the force fitting section (30) and the body (25). With help of the conical area (36), the wheel bolt (21 ) located according to the axis (29) is easily mounted to mounting part (22) in direction of axial force (28). With help of such positioning, centralization is also provided. The body (25) has a transition area (37) connected to conical area (36). Outer diameter of body (38) is smaller than outer diameter of square section profile (34). Outer diameter of the body (38) is the outer diameter of the metal bar body used to produce the wheel bolt (21 ). The body (25) has a fixing area (39). Fixing area (39) contains threads (40) in order to provide connection to an area. Maximum outer diameter (41 ) of fixing part (39) is always smaller than

outer diameter (34) of square section profile. Outer diameter (41 ) of fixing area (39) is also smaller than diameter of force fitting section (30). Inner diameter (42) of the threads (40) is smaller than outer diameter (38) of the body. The head (24) of the wheel bolt (21 ) has a fixing area (43). In this case, mounting part (22) has to have a fixing area (44) in order to prevent twisting of the wheel bolt (21 ).

Figure 3 shows side and top views of the wheel bolt (21 ) being subject of this invention. As it can be seen from the figure, the wheel bolt (21 ) being subject of the invention consists of having head (24), square section profile (31 ) formed on the force fitting section (30), body (5) and fixing part (39) having threads (40).

Figure 4 shows the view indicating detail A given in Figure 3. The contact surface (45) of the square section profile (31 ) contacts minimum 30% of the cylindrical area of the hub hole (23). Knurl thread top (46) and knurl thread bottom (47) of the square section profile (31 ) facilitating installation of the wheel bolt (21 ) to hub hole (23) have been rounded in order to increase the strength of the square section profile (31) and eliminate the probable risk of breaking. There is a flank angle (48) between knurls (32) of the square section profile (31) in order to spread the relocated material with cold deformation during installation of the wheel bolt (21 ) to hub hole (23), into a bigger diameter. Flank angle (48) varies between 0 and 30 degrees and is preferably 15 degrees.

The invention cannot be limited with the representative applications given in this section. Alternative developments to be developed by persons skilled in the related art based on basic factors under protection as specified in claims shall mean violation of the invention.