Technological Aspect:

The invention is related to a passenger car wheel-wheel bolt connection which ensures to fasten the wheel to the wheel hub.

The invention is related to a wheel-wheel bolt connection which prevents bolt loosening problems under vibration conditions.

State Of The Art:

In the automotive industry, different automotive manufacturers fasten their aluminum alloy wheels to the wheel hub, using wheel bolts that have different geometries and sizes. This assembly between wheel and wheel bolts are called the wheel-wheel bolt connection. There can be several number of lug holes on the wheel depending on the design. The bolts are screwed to the hub by passing through these holes, thus providing the connection of the wheel and the hub after applying an assembly torque to the bolt. The geometry of the wheel and wheel bolt’s connection surface can be listed as conical, spherical, flat and so on. The present invention discloses a wheel and wheel bolt connection with conical geometry.

In the prior art, the problem of loosening problem is observed in the wheel-wheel bolt connections, when exposed to high vibration caused by service conditions. As a result of loosening, there can be safety problems. This situation may cause dangers in terms of vehicle and passenger safety. In order to prevent loosening problems, a wheel-wheel bolt connection with enhanced vibration resistance is required.

US3967669A document discloses, a wheel-wheel bolt connection with a conical geometry is described. A wheel-wheel bolt geometry disclosed in the document is not a solution for the problem of loosening and increased vibration resistance. US6106077A document discloses, a bolt structure for vehicle wheels is described. On said document, it is not mentioned 65,5 degree angle of the lug hole on the wheel and 64 degree angle of wheel.

US20030068212A1 discloses to the connection of a wheel bolt nut and bolt hole. Here, the outer surface of wheel bolt nut is covered with a coating made of elastic material.

As a result, there is a need for a wheel-wheel bolt connection, that is beyond the prior art and overcome the disadvantages of prior art.

A Brief Description of Invention:

The invention relates to a wheel-wheel bolt connection that has superior properties over the state of the art.

The main object of the invention is a new design wheel- wheel bolt connection which minimizes the loosening problems caused by in contrast to present Wheel-wheel bolt connections used in automotive industry.

Another object of the invention is to provide a new wheel-wheel bolt connection in which the fastening angle of the wheel bolt and the wheel is determined and joint surface of the wheel lug hole and bolt are both redesigned in suitable geometry as a result of tests and experiments.

In order to achieve all the objectives mentioned above and which will emerge from the following detailed description, present invention relates to wheel and wheel bolt connection comprising head of bolt, threaded bolt surface and bolt hole with conical connection surface, which has enhanced vibration resistance in order to eliminate loosening problems. The feature of the invention is to provide the optimum geometry that maximizes the vibration resistance in order to reduce the loosening speed between the wheel and the wheel bolt, where the conical surface angle on the wheel bolt is at a 65.5 degree (± 0.15 °) , and the bolt surface on the bolt hole is at a 64 degree conical angle (on machining tolerances range) and the critical radius having between 1.75 and 2 mm on the point of where the point of head of bolt and conical connection surface’s contacts.

The other feature of this invention is, the surface angle of bolt hole angle and the surface angle of conical connection on wheel bolt is different from each other.

Description of the Figures:

The invention will be described with reference to the attached figures, so that the features of the invention will be more clearly understood. However, it is not intended to put some limitations by particular adjustments. On the contrary, it is also intended to cover all alternatives, modifications and equivalents that may be included within the scope of the invention as defined by the appended claims. It should be understood that the details are shown solely for the purpose of illustrating preferred embodiments of the present invention and are provided for both the shaping of methods and the most useful and easily understandable description of the rules and conceptual features of the invention. On these figures;

Figure - 1 These are the side views of the wheel bolt produced according to the invention.

Figure - 2 It is a sectional view of the wheel bolt used in the invention.

Figure - 3 It is a sectional view of the wheel before wheel bolts are placed on it.

Figure - 4 It is a sectional view of the wheel bolt before they are placed on wheel.

Figure - 5 Reduction graphic of locking force of wheel-wheel bolt connections that have been used by different automotive manufacturers.

Figure - 6 The graphic of the loosening rate in the wheel - wheel bolt connection compared to the difference between the surface angle of the conical connection surface and the lug hole angle on the wheel that have obtained by design and simulation studies.

Figure - 7 The comparison chart of wheel- wheel bolt connections of present invention and wheel- wheel bolt connections in the prior art. Explanation of References:

10. Wheel bolt

11. Head of bolt

12. Conical connection surface

121. Surface angle

122. Radius

13. Bolt thread surface

20. Wheel

21. Lug hole

211. Lug hole angle

Detailed Description of Invention:

In this detailed description, the wheel-wheel bolt connection according to the invention is explained only with examples for a better understanding of the subject, without any limiting effects. The specification describes a wheel-wheel bolt connection with increased vibration resistance to prevent loosening problems.

In Figure 1 , the side view of the wheel bolt (10) and wheel (20) elements used in the wheel-wheel bolt connection according to the invention is given. Accordingly, the wheel bolt (10) includes the bolt thread surface (13) that enables the wheel bolt (10) to be mounted on the vehicle hub by passing the head of bolt (11 ) on the wheel (20) through the lug hole. (21 ). In the wheel (20) provided by using the wheel bolt (10) and the conical connection surface (12) on the wheel bolt (10), it fits into the lug hole (21 ) on the wheel (20). The connection provided by the conical connection surface (12) with the lug hole (21 ) is described as the wheel-wheel bolt connection. In the invention, the surface angle (121 ) of the conical connection surface (12) is designed as 65.5° (± 0.15 °). At the point where the conical connection surface (12) meets the head of bolt (11 ), there is a critical radius (122) of 1.75-2 mm. At the same time, lug hole angle (211 ) of the lug hole (21 ) located on the wheel (20) is designed as 64° (within the machining tolerance range). In the invention, the surface angle (121 ) of the wheel bolt (10), the lug hole angle (211 ) of the wheel (20) and the critical radius (122) value are determined as a result of tests and experiments are the optimum measurement values for maximum vibration resistance. In Figure 2, the sectional view of the wheel bolt (10) is given. In sectional view, the surface angle (121 ) of the conical connection surface (12) can be seen in detail.

In Figure 3, the sectional view of the wheel (20) before the wheel bolt (10) enters the wheel (20) and in Figure 4, after the wheel bolt (10) is placed on the wheel (20) is given. When the figures are examined, the connection type exists between the wheel (20) and the wheel bolt (10) can be clearly understood.

The wheel bolt (10) is fastened on the wheel (20) at a certain bolt tightening torque and the wheel bolt (10) exites the locking force to provide the connection. When the connection exposed to vibration, there is a decrease in the clamping force. The amount of reduction in the locking force compared to the vibration cycle indicates the vibration resistance of the connection. Junker vibration test results of the wheel-load given in Figure 5. As a result of the vibration tests carried out, it was determined that some wheel-wheel bolt groups (D1 and B1 ) were completely loosened under 1000 cycles (sudden decrease in locking load) and some (A1 ) experienced high loss in locking force. When the ones with higher vibration resistance (E1 , C1 and F1 ) were examined, it was determined that the highest vibration resistance (E1 ) belonged to the wheel-wheel bolt group.

The mapping results obtained from the design and vibration made by computer simulation on the wheel-wheel bolt set with the highest vibration resistance (E) given in Figure 5, are shown in Figure 6. In this chart, the x-axis is the difference between the surface angle (121 ) of the conical connection surface (12) and the lug hole angle (211 ) of the lug hole (21 ) located on the wheel (20). The Y-axis, on the other hand, shows the loss in the locking load in each vibration cycle in kN. In the chart, the loosening rate curve (A2) of the wheel bolt (10) with an angle of 65.5 ° (± 0.15 °) and the loosening rate curves (E2, F2) belonging to the group of wheel bolts (10) with different angles are given. As can be seen from the graph, the value closest to the zero point in the loosening rate collected was obtained at the point (B2) in the curve (A2). At this point, the difference between the surface angle (121 ) of the conical connection surface (12) and the lug hole angle (211 ) of the lug hole (21 ) on the wheel (20) is 1.5 degrees. For this reason, the lug hole angle (211 ) of the lug hole (21 ) located on the wheel (20) is 64 degrees (at the machining tolerance ranges). The loosening rate obtained in the vibration test with the prototypes of the wheel-wheel bolt connection produced at these angle values is shown at point (C2). This result shows that the wheel-wheel bolt connection according to the invention obtained by design and simulations has high vibration resistance.

According to the vibration tests used and made on the market, the wheel-wheel bolt connection (B3) with the highest vibration resistance that available on the market and the wheel-wheel bolt connection (A3) according to the invention were put into the Junker vibration test and compared. Figure 7 shows the chart showing the Junker vibration test result. In order to the chart, the wheel-wheel bolt connection (A3) according to the invention has much higher vibration resistance than the highest resistance wheel-wheel bolt connection that can be find on market (B) (also curve (E1 ) given in Figure 5). As the resistance of the wheel-wheel bolt connection (A3) of the present invention to vibration is high, the loosening rate decreases significantly. In this way, loosening problems are prevented.