Hub screw with spaced knurls

Abstract

The utility model belongs to the technical field of automobile engineering and mechanical connection, and particularly relates to a hub screw rod with interval type knurls, which comprises a screw rod body and a plurality of interval type knurling parts arranged on the outer surface of the lower half part of the screw rod body, the knurling parts are evenly distributed in the circumferential direction of the screw body. And the outer diameter of each knurling part is larger than that of the corresponding part of the screw body, so that enhanced locking force, friction force and the like are provided. In the design of the interval type knurling parts, the friction force between the bolt and a screw hole is obviously enhanced by increasing the contact area and the sawtooth edges, and stable connection is ensured; due to the uniform distribution design, stress is effectively dispersed, the overall strength and durability are improved, more importantly, due to the interval design, permanent deformation caused by multiple times of installation of the screw holes is reduced, the service life of the hub is prolonged, and the maintenance cost is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical fields of automotive engineering and mechanical connection, and particularly relates to a wheel hub screw with spaced knurling. Background Art

[0002] In the automotive industry, as a key component for connecting the wheel hub, steel rim and tire, the fastening and stability of the tire bolt are directly related to the driving safety of the vehicle. During the vehicle driving process, the tire bolt must form a tight fit with the screw hole on the wheel hub, and a locking nut is used to ensure that components such as the wheel hub, steel rim and tire form a stable whole. This stable structure is the basis for ensuring the safe driving of the vehicle under various road conditions;

[0003] However, with the use of the vehicle and the replacement of the tire, the fit state between the tire bolt and the wheel hub screw hole may change. Specifically, when the tire bolt bears the vehicle weight and the vibration and impact force during driving for a long time, the tight fit between it and the wheel hub screw hole may gradually become loose, resulting in serious consequences such as the nut becoming loose, the steel rim shifting or even the screw breaking. More seriously, once the fit between the tire bolt and the screw hole fails, the entire tire may fall off the wheel hub, posing a great threat to driving safety;

[0004] To solve this problem, a special design - serrated knurling - is usually adopted for the screw part of the tire bolt. The outer diameter of this knurling is slightly larger than the inner diameter of the wheel hub screw hole. During installation, the serrated knurling of the screw is pressed into the screw hole by a press. Since the outer diameter of the knurling is slightly larger, the screw hole will be slightly enlarged during the pressing process, and at the same time, the knurling itself will also be compressed to a certain extent. This design makes a tight and interference fit between the knurling and the screw hole, thus effectively preventing the loosening phenomenon from occurring;

[0005] However, this design also has certain limitations. When the tire bolt needs to be replaced, since the wheel hub screw hole has been slightly enlarged due to the previous installation, a screw with a larger outer diameter of the knurling must be used to ensure the new tight fit. As the number of tire bolt replacements increases, the wheel hub screw hole will continue to expand until it can no longer accommodate a screw with a larger outer diameter of the knurling. At this time, the wheel hub itself will be unable to continue to be used due to the damage of the screw hole, and the vehicle has to replace the new wheel hub, which undoubtedly increases the use cost and maintenance difficulty of the vehicle;

[0006] Therefore, how to ensure the tight fit between the tire bolt and the wheel hub screw hole while extending the service life of the wheel hub and reducing the additional cost caused by replacing the tire bolt has become an urgent problem to be solved in the current automotive industry. Content of the Utility Model

[0007] (1) Technical problems to be solved

[0008] To solve the defects presented in the above-mentioned background art, the present utility model proposes a wheel hub screw with spaced knurling that can extend the service life of the wheel hub.

[0009] (2) Technical solutions

[0010] The present utility model is realized through the following technical solutions: The present utility model proposes a wheel hub screw with spaced knurling, including a screw body and a plurality of spaced knurling portions arranged on the outer surface of the lower half of the screw body;

[0011] The knurling portions are evenly distributed along the circumferential direction of the screw body;

[0012] The outer diameter of each knurling portion is larger than the outer diameter of the corresponding part of the screw body to provide enhanced locking force and friction.

[0013] Preferably, the knurling portion is composed of a plurality of equally spaced serrated knurling units, and each serrated knurling unit has a sharp serrated edge to enhance the friction with the mating parts.

[0014] Preferably, the knurling portion further adopts an upper and lower multi-layer structure design, where a predetermined spacing is maintained between the layers of the knurling portions, and the serrated shapes and sizes of the layers of the knurling portions can be the same or different to adapt to different application requirements.

[0015] Preferably, the specific dimensions of the knurling portion include but are not limited to the knurling outer diameter D, the knurling depth H, the knurling pitch P, and the layer spacing S between the multi-layers of knurling: where:

[0016] The knurling outer diameter D is 0.5% to 5% larger than the diameter D' of the screw body at this position, and the specific value is determined according to the application requirements;

[0017] The knurling depth H is 0.5% to 5% of the diameter D' of the screw body at this position to ensure sufficient friction without affecting the strength of the screw;

[0018] The knurling pitch P is the distance from the edge to the edge of the knurling portion, and is between 15% and 150% of the diameter D' of the screw body at this position to maintain a uniform distribution and sufficient strength;

[0019] When adopting the upper and lower multi-layer structure design, the layer spacing S is not less than 5% of the diameter D' of the screw body at this position to ensure the independence and effectiveness of each layer of the knurling portion.

[0020] Preferably, D' here may not be the maximum diameter of the screw rod body, but rather refers to the diameter of the screw rod body at the position where the knurled portion is located. Since the diameter of the screw rod body may vary accordingly according to the shape of the screw hole, in practical applications, the specific value of D' should be determined according to the specific situation.

[0021] (III) Beneficial Effects

[0022] The utility model has the following beneficial effects compared with the prior art:

[0023] The design of the spaced knurled portion of the utility model not only significantly enhances the friction between the bolt and the screw hole by increasing the contact area and the serrated edge, ensuring a firm connection; but also its evenly distributed design effectively disperses stress, improves the overall strength and durability. More importantly, the spaced design reduces the permanent deformation of the screw hole caused by multiple installations, extends the service life of the wheel hub, and reduces the maintenance cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Other features, objects, and advantages of the utility model will become more apparent from the following detailed description of non-limiting embodiments read in conjunction with the accompanying drawings:

[0025] Figure 1 It is a three-dimensional structural schematic diagram of the utility model.

[0026] Figure 2 It is a planar development view of the knurling of the utility model.

[0027] The reference signs in the drawings are: 1 - screw rod body, 2 - knurled portion. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] In this technical solution:

[0029] In order to make the purpose, technical solution, and advantages of the utility model clearer, the following further details the utility model in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model and are not used to limit the utility model.

[0030] Referring to Figure 1 - Figure 2 As shown, the utility model provides a wheel hub screw with spaced knurling, including a screw rod body and a plurality of spaced knurled portions arranged on the outer surface of the lower half of the screw rod body;

[0031] The knurled portions are evenly distributed along the circumferential direction of the screw rod body;

[0032] The outer diameter of each knurled portion is larger than the outer diameter of the corresponding part of the screw rod body to provide enhanced locking force and friction.

[0033] Among them, the knurled part is composed of a plurality of equally spaced serrated knurling units, and each serrated knurling unit has a sharp serrated edge to enhance the friction with the mating part.

[0034] Among them, the knurled part further adopts an upper and lower multi-layer structure design, where a predetermined spacing is maintained between the layers of the knurled part, and the serrated shapes and sizes of the layers of the knurled part can be the same or different to meet different application requirements.

[0035] Among them, the specific dimensions of the knurled part include but are not limited to the knurled outer diameter D, the knurled depth H, the knurled pitch P, and the layer spacing S between the multi-layer knurling: where:

[0036] The knurled outer diameter D is 0.5% to 5% larger than the diameter D' of the screw body (1) at this position, and the specific value is determined according to application requirements;

[0037] The knurled depth H is 0.5% to 5% of the diameter D' of the screw body (1) at this position to ensure sufficient friction without affecting the screw strength;

[0038] The knurled pitch P is the distance from edge to edge of the knurled part, and is set to be between 15% and 150% of the diameter D' of the screw body (1) at this position to maintain a uniform distribution and sufficient strength;

[0039] When adopting the upper and lower multi-layer structure design, the layer spacing S is not less than 5% of the diameter D' of the screw body (1) at this position to ensure the independence and effectiveness of each layer of the knurled part.

[0040] Among them, D' here may not be the maximum diameter of the screw body, but refers to the diameter of the screw body at the position where the knurled part is located. Since the diameter of the screw body may change accordingly according to the shape of the screw hole, therefore, in actual applications, the specific value of D' should be determined according to the specific situation.

[0041] Principle analysis

[0042] For the hub screw with spaced knurling proposed by the present utility model, its design principle is based on enhancing the tight fit and friction between the bolt and the hub screw hole to achieve a more stable connection and a longer service life. The following is a detailed analysis of this principle:

[0043] Principle of the knurling design:

[0044] Increase in the knurled outer diameter: The outer diameter of the knurled part is designed to be slightly larger than the outer diameter of the screw body and also slightly larger than the inner diameter of the hub screw hole. This design enables the sharp serrated edge of the knurling to embed into the screw hole wall when the knurled part is pressed into the screw hole during installation, forming a mechanical lock.

[0045] Knurling Depth and Shape: The knurling depth is moderate, ensuring sufficient friction while not being too deep to affect the strength of the screw. The serrated knurling units have sharp edges, which can more effectively increase the contact area and friction with the screw hole wall, preventing loosening.

[0046] Advantages of Intermittent Knurling:

[0047] Uniform Distribution: The knurled parts are evenly distributed along the circumference of the screw body, ensuring balanced stress on the screw in all directions and improving overall stability.

[0048] Interval Control: The interval distance between adjacent knurled parts remains consistent and is determined according to the diameter of the screw body. This design not only ensures the uniform distribution of the knurled parts but also avoids performance degradation caused by overly large or small intervals.

[0049] Multi - layer Knurling Structure:

[0050] Independence and Adaptability: The multi - layer knurling structure design allows for a predetermined spacing between each layer of knurled parts, and the serration shapes and sizes of each layer of knurled parts can be the same or different. This design improves the independence and adaptability of the knurled parts, enabling optimization and adjustment according to different application requirements.

[0051] Enhanced Tight - Fit Degree: The multi - layer knurling structure further enhances the tight - fit degree between the screw and the screw hole, maintaining good connection stability even after multiple bolt replacements.

[0052] Formation of Tight - Fit during Installation:

[0053] Press Installation: During installation, a press is used to press the serrated knurling of the screw into the hub screw hole. Since the knurling outer diameter is slightly larger than the screw hole inner diameter, the part of the screw hole in contact with the knurling will slightly expand during the pressing process, and the knurling itself will also be slightly compressed. This interference fit forms a tight locking relationship between the knurling and the screw hole.

[0054] Non - contact Parts Do Not Deform: It should be noted that the part of the hub screw hole that does not come into contact with the knurling will not deform, which provides favorable conditions for subsequent bolt replacement.

[0055] Mechanism for Prolonging Hub Service Life:

[0056] Reducing Screw Hole Expansion: Since the intermittent knurling positions of each screw are not exactly the same, when a new screw is replaced, the non - expanded part of the hub screw hole can form a tight fit with the new knurling. In this way, the problem of having to use a screw with a larger knurling outer diameter to adapt to the already expanded screw hole every time a replacement is made is avoided, thus prolonging the service life of the hub.

[0057] Stable Structure: Through the above design, a stable and lasting tight fit relationship can be formed between the tire bolt and the hub screw hole, providing a strong guarantee for the driving safety of the vehicle.

[0058] Example 1: Passenger car wheel hub screw

[0059] Diameter of the screw body: M14 (i.e., the nominal diameter is 14 mm)

[0060] Outside diameter D of the knurling: 14.28 mm (2% larger than the diameter of the screw body at this position, i.e., 14 mm * 1.02 = 14.28 mm)

[0061] Depth H of the knurling: 0.21 mm (1.5% of the diameter of the screw body at this position, i.e., 14 mm * 0.015 = 0.21 mm)

[0062] Pitch P of the knurling: 2.8 mm (20% of the diameter of the screw body at this position)

[0063] Number of knurled parts: 6 knurled parts evenly distributed along the circumferential direction

[0064] Installation effect: After installation by a press, the knurled part forms a firm mechanical lock with the hub screw hole. After replacing the tire bolt multiple times, the deformation of the hub screw hole is extremely small, maintaining a good tight fit state.

[0065] Example 2: Heavy truck wheel hub screw

[0066] Diameter of the screw body: M24 (i.e., the nominal diameter is 24 mm)

[0067] Outside diameter D1 of the first layer of knurling: 24.24 mm (1% larger than the diameter of the screw body at this position, i.e., 24 mm * 1.01 = 24.24 mm)

[0068] Depth H1 of the first layer of knurling: 0.24 mm (1% of the diameter of the screw body at this position, i.e., 24 mm * 0.01 = 0.24 mm)

[0069] Outside diameter D2 of the second layer of knurling: 24.36 mm (1.5% larger than the diameter of the screw body at this position, i.e., 24 mm * 1.015 = 24.36 mm)

[0070] Depth H2 of the second layer of knurling: 0.24 mm (1% of the diameter of the screw body at this position, i.e., 24 mm * 0.01 = 0.24 mm)

[0071] Layer spacing S: 2.16 mm (9% of the diameter of the screw body at this position, which is 24 mm, i.e., 24 mm * 0.09 = 2.16 mm)

[0072] Knurling pitch P: 3.6 mm (15% of the diameter of the screw body at this position, which is 24 mm)

[0073] Number of knurled parts: 8 knurled parts are evenly distributed along the circumferential direction (16 knurling units in two layers)

[0074] Installation effect: Under the harsh road conditions of heavy trucks, the double-layer knurling design significantly improves the connection strength and anti-fatigue performance, ensuring the stable connection between the tire bolt and the wheel hub.

[0075] Example 3: Screw for high-performance racing wheel hub

[0076] Diameter of the screw body: M12 (customized according to the specific requirements of the racing car)

[0077] Outer diameter of the knurling D: Precise calculated value, assumed to be 12.25 mm (determined specifically according to the size of the screw hole of the racing wheel hub and the required tight fit)

[0078] Knurling depth H: 0.10 mm (Considering the dual requirements of lightweight and strength for racing cars, it is set to approximately 8.3% of the diameter of the screw body, i.e., 12 mm * 0.083 ≈ 0.10 mm, rounded to two decimal places)

[0079] Knurling pitch P: Precise calculated according to the number of knurled parts and the diameter of the screw body at this position, assumed to be 2.2 mm (to ensure even distribution)

[0080] Material of the knurled part: Special alloy material is used to improve hardness and wear resistance

[0081] Number of knurled parts: Evenly distributed along the circumferential direction, determined according to the size of the racing wheel hub and the need for quick replacement, assumed to be 4 knurled parts

[0082] Installation effect: The specially customized knurling design and material selection enable the tire bolt to be replaced quickly and safely during a racing car competition, while maintaining excellent connection stability.

[0083] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model.

[0084] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, "a plurality of" means two or more unless otherwise specifically defined.

[0085] In the present utility model, unless otherwise clearly defined and limited, the terms such as "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0086] In the present utility model, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "over" and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "under" and "beneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature.

[0087] The above are only the preferred embodiments of the present utility model and are not used to limit the present utility model. For those skilled in the art, the present utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A hub screw with spaced knurling, characterized in that: It comprises a screw body (1) and a plurality of spaced knurled portions (2) arranged on the outer surface of the lower half of the screw body (1); The knurled portions (2) are evenly distributed along the circumferential direction of the screw body (1); The outer diameter of each knurled portion (2) is greater than the outer diameter of a corresponding portion of the screw body (1).

2. A hub screw with spaced knurling according to claim 1, characterized in that: The knurling portion (2) is composed of a plurality of equidistant serrated knurling units, each of which has a sharp serrated edge.

3. The hub screw with spaced knurling according to claim 1, characterized in that: The knurled portion (2) further adopts an upper and lower multi-layer structural design, wherein a predetermined spacing is maintained between each layer of the knurled portion (2), and the sawtooth shapes and sizes of each layer of the knurled portion (2) may be the same or different.

4. A hub screw with spaced knurling according to any one of claims 1 to 3, characterized in that: The specific dimensions of the knurled portion (2) include but are not limited to the knurled outer diameter D, the knurled depth H, the knurled spacing P, and the spacing S between multiple layers of knurling: The knurl outer diameter D is 0.5% to 5% larger than the diameter D' of the screw body (1) at that position; The knurling depth H is 0.5% to 5% of the diameter D' of the screw body (1) at that position; The knurling pitch P is the distance from edge to edge of the knurling portion (2), and is set to be between 15% and 150% of the diameter D' of the screw body (1) at that position; When an upper and lower multi-layer structure is adopted, the layer spacing S is not less than 5% of the diameter D' of the screw body (1) at that position.

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