A double-coated driving shaft assembly bolt

Abstract

The utility model discloses a kind of bolts for double-coated transmission shaft assembly, including bolt body, the bolt body includes thread section, thread section is coated with positioning layer, the tail end part of positioning layer is close to thread section, thread section is coated with anti-loosening layer, and the anti-loosening layer covers positioning layer;The utility model can realize accurate monitoring during assembly process, and eliminate the phenomenon of top tooth.

Description

Technical Field

[0001] This utility model relates to the field of new energy vehicle transmission system assembly technology, and more specifically to a bolt for assembling a double-coated transmission shaft. Background Technology

[0002] In the powertrain system of new energy vehicles, the driveshaft, as the core component connecting the motor and the drive wheels, directly determines the vehicle's driving safety and power output stability through its transmission reliability. Currently, most mainstream new energy vehicle driveshafts adopt a two-way gear transmission structure. This structure achieves bidirectional power transmission through gear meshing. During the assembly stage, it is necessary to ensure precise gear alignment, that is, complete meshing between the rack and the gear, in order to guarantee no abnormal impact during subsequent transmission.

[0003] However, in actual mass production scenarios, due to limitations in the assembly station layout, differences in operator precision, or the accumulation of minor dimensional tolerances after the transmission shaft gears are machined, the phenomenon of "tooth misalignment" (commonly known in the industry as "gear not meshing") occasionally occurs, where the rack and gear fail to fully engage. When the transmission shaft gears are in normal meshing, the rotation angle is above 1550° during the tightening process from 6 Nm torque to 100 Nm torque; when in the tooth misalignment state, the rotation angle is below 1500° within the same torque range. This phenomenon is difficult to identify with the naked eye after assembly, but it will expose serious problems during vehicle testing: when the driveshaft is in the toothed state, the gears cannot form an effective meshing transmission, and a violent "tooth-gripping" noise will be generated during vehicle operation, accompanied by direct collision and wear of the gear teeth. More seriously, the toothed state will cause abnormal tightening force of the bolts during the assembly of the driveshaft. The bolts cannot reach a stable preload as required by the design. Under conditions such as vehicle bumps and high-speed driving, the bolts are prone to loosening or even falling off, which will lead to driveshaft transmission failure. In extreme cases, it may cause driveshaft breakage, vehicle loss of control, and ultimately serious road traffic safety accidents, posing a major threat to the lives of drivers and passengers.

[0004] Therefore, this utility model proposes a bolt for assembling a double-coated drive shaft. Utility Model Content

[0005] The purpose of this utility model is to provide a bolt for assembling a double-coated drive shaft, which can achieve precise monitoring of the assembly process and eliminate tooth tipping.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A bolt for assembling a double-coated drive shaft includes a bolt body, the bolt body including a threaded section, the threaded section being coated with a positioning layer near the tail end of the threaded section, and the threaded section being coated with an anti-loosening layer covering the positioning layer.

[0008] Furthermore, the bolt body is a twelve-angle flange bolt, and the bolt body is fully coated with a zinc-aluminum coating.

[0009] Furthermore, the positioning layer is made of threaded nylon locking adhesive.

[0010] Furthermore, the coating thickness of the thread-locking nylon adhesive is 0.1-0.2 mm.

[0011] Furthermore, the anti-loosening layer is a thread lubricating and locking adhesive layer.

[0012] Furthermore, the coating thickness of the thread lubrication and locking adhesive layer is 0.05-0.1 mm.

[0013] Furthermore, the anti-loosening layer has a wider coating than the positioning layer, and the anti-loosening layer near the head of the bolt body is parallel to the positioning layer near the head of the bolt body.

[0014] Beneficial effects: This utility model uses threaded nylon locking adhesive coating, which forms a uniform elastic film after curing. The film has a certain elasticity, which can buffer the small impact force at the beginning of bolt tightening, ensuring that the torque starts from the "initial tightening torque monitoring point (6Nm)", guaranteeing a linear and predictable transmission relationship with the rotation angle. It can also accurately identify the meshing state of the drive shaft gear, realize the detection of tooth backlash, avoid tooth breakage during test runs and subsequent safety accidents, and improve vehicle driving safety. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0016] Figure 1 This is a schematic diagram of the structure of this utility model;

[0017] Figure 2 This is a schematic diagram of the coating positioning layer structure of this utility model.

[0018] Reference numerals: 1. Bolt body; 2. Threaded section; 3. Positioning layer; 4. Anti-loosening layer. Detailed Implementation

[0019] like Figures 1 to 2As shown in this specific embodiment, a bolt for assembling a double-coated drive shaft includes a bolt body 1, which is a twelve-angle flange bolt. The bolt body 1 is fully coated with a zinc-aluminum coating to ensure that the bolt has the strength and corrosion resistance to adapt to the high torque conditions of the drive shaft of new energy vehicles, and to avoid thread corrosion caused by coating peeling during long-term use.

[0020] like Figure 2 As shown, the bolt body 1 includes a threaded section 2, on which a positioning layer 3 is coated. The positioning layer 3 is located near the tail end of the threaded section 2 and is made of thread-locking nylon adhesive. A medium-strength thread-locking nylon adhesive is selected and sprayed at a flow rate of 0.2 mL / s using a spraying device. During the spraying process, the bolt body 1 rotates slowly at a speed of 5 r / min to ensure that the adhesive is sprayed onto the tail end of the threaded section 2. After spraying, the thickness of the adhesive layer is measured by a laser thickness gauge and controlled to be between 0.1-0.2 mm (the actual measured average thickness is 0.15 mm). After spraying, the bolt is transferred to a constant temperature curing zone and left to stand until the adhesive layer is completely cured to avoid mixing of the two layers of adhesive during subsequent spraying. The coating thickness of the thread-locking nylon adhesive is 0.1-0.2 mm, which ensures the uniformity and stability of the adhesive layer and avoids unstable torque transmission due to an excessively thin adhesive layer and thread engagement jamming due to an excessively thick adhesive layer. After curing, the thread-locking nylon adhesive forms a uniform elastic film that can precisely fill the tiny gaps between the threads. On the one hand, the film can eliminate local jamming or excessive gaps caused by poor thread surface roughness, making the friction during bolt engagement more stable. On the other hand, the film has a certain degree of elasticity, which can buffer the small impact force at the beginning of bolt engagement, ensuring that the torque can form a linear and predictable transmission relationship with the rotation angle from the "initial tightening torque monitoring point (6Nm)". This avoids the distortion of monitoring data caused by "torque jump" in the absence of adhesive, and lays a precise benchmark for subsequent judgment of gear status by rotation angle.

[0021] When the drive shaft gears are in normal meshing, the bolt rotation angle is above 1550° during the tightening process from 6 Nm to 100 Nm. When the gears are in an abnormal state, the rotation angle is below 1500° within the same torque range. The nylon thread-locking adhesive applied in this application allows the bolt's engagement resistance to be analyzed to determine the drive shaft gear meshing state. When the drive shaft is under balanced stress, the bolt only needs to overcome the friction of the thread adhesive film and normal assembly resistance during tightening. The resistance is stable and controllable, thus allowing for tightening from 6 Nm to 100 Nm. During the torque increase process, the bolt rotation angle can be maintained above 1550°; if the gear tooth is engaged, there will be rigid contact between the gears, which will increase the bolt engagement resistance, causing the bolt to not turn under the same torque, and the rotation angle will be compressed to below 1500°. Therefore, the tooth engagement phenomenon can be detected, avoiding tooth breakage during test runs and subsequent safety accidents, and improving vehicle driving safety. It is precisely because the thread nylon locking adhesive eliminates irrelevant interference such as thread clearance and surface roughness that assembly personnel can accurately identify tooth engagement faults through the rotation angle threshold, avoiding the problem of tooth engagement that traditional processes cannot identify or miss.

[0022] like Figure 1 As shown, the threaded section 2 is coated with an anti-loosening layer 4, which covers the positioning layer 3. The anti-loosening layer 4 is a thread lubricating and locking adhesive layer. A thread lubricating and locking adhesive containing solid lubricant is selected. Using the above tooling positioning and spraying parameters, the spraying flow rate is adjusted to 0.15 mL / s. Spraying is performed on the outside of the cured nylon locking adhesive layer. The thickness of the adhesive layer is controlled at 0.05-0.1 mm (the measured average thickness is 0.08 mm). The coating area is larger than the nylon locking adhesive. After spraying, it is allowed to air dry naturally to complete the preparation of the double-coated bolt. The coating thickness of the thread lubricating and locking adhesive layer is 0.05-0.1 mm. While ensuring the anti-loosening effect, the hardness of the adhesive layer after curing is reduced, allowing the bolt to be repeatedly disassembled, improving the efficiency of component interchangeability and maintenance.

[0023] The anti-loosening layer 4 has a wider coating than the positioning layer 3. The anti-loosening layer 4 is parallel to the head of the bolt body 1 near the head of the positioning layer 3 near the head of the bolt body 1. The threaded nylon locking adhesive layer and the threaded lubricating locking adhesive layer are designed in layers and cured sequentially, so that the torque reference establishment and anti-loosening function do not interfere with each other and work together. The nylon adhesive layer ensures stable torque transmission, and the lubricating adhesive layer prevents the bolt from loosening under vehicle bumps and high torque conditions. The combination of the two ensures long-term stable transmission of the drive shaft, which is suitable for the high torque and high reliability transmission system requirements of new energy vehicles.

[0024] Working principle: The threaded section 2 of the bolt body 1 is coated with a threaded nylon locking adhesive layer, which forms a uniform and stable elastic film after curing. This film can fill the tiny gaps between the threads. When the bolt is screwed in, this film can provide a stable initial frictional force, ensuring that the bolt can establish a linear torque and angle transmission relationship from the initial tightening stage (torque up to 6Nm). This avoids torque fluctuations caused by differences in thread surface roughness when there is no adhesive or a single adhesive type. It provides accurate reference data for judging the gear status by angle, solving the problem of torque and angle correlation failure in traditional processes. The thread lubrication locking adhesive layer covering the outside of the nylon locking adhesive layer can reduce the friction coefficient when the bolt is screwed in, ensuring that the torque during tightening is mainly used for gear position calibration rather than overcoming friction. On the other hand, it slowly cures after the bolt reaches the design preload (100Nm), forming a removable locking effect. This can prevent the bolt from loosening while the vehicle is in motion, and the bolt can be disassembled with conventional tools when adjusting the top gear, allowing the bolt to be reused.

[0025] The meshing state of the drive shaft gears directly affects the bolt tightening resistance: When the gears are normally meshed, the drive shaft is subjected to balanced force, and the resistance that the bolts need to overcome when tightening is stable. During the process of tightening from a torque of 6 Nm to a torque of 100 Nm, the bolt rotation angle remains above 1550° due to the stable resistance. When the gear teeth are engaged, there is rigid contact between the gears, which will increase the bolt tightening resistance. This causes the bolt rotation angle within the same torque range to be compressed, all below 1500°. By monitoring the rotation angle data in this torque range, the gear meshing state can be directly judged in reverse, and the engagement fault can be identified.

[0026] The above are merely preferred embodiments of this utility model. The protection scope of this utility model is not limited to the above embodiments. All technical solutions falling within the scope of this utility model's concept are within its protection scope. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of this utility model should also be considered within its protection scope.

Claims

1. A bolt for assembling a double-coated drive shaft, comprising a bolt body (1), characterized in that, The bolt body (1) includes a threaded section (2), a positioning layer (3) is coated on the threaded section (2), the positioning layer (3) is close to the tail end of the threaded section (2), and an anti-loosening layer (4) is coated on the threaded section (2), the anti-loosening layer (4) covers the positioning layer (3).

2. The bolt for assembling a double-coated drive shaft according to claim 1, characterized in that, The bolt body (1) is a twelve-angle flange bolt, and the bolt body (1) is fully coated with a zinc-aluminum coating.

3. The bolt for assembling a double-coated drive shaft according to claim 1, characterized in that, The positioning layer (3) is threaded nylon locking adhesive.

4. The bolt for assembling a double-coated drive shaft according to claim 3, characterized in that, The coating thickness of the thread-locking nylon adhesive is 0.1-0.2 mm.

5. The bolt for assembling a double-coated drive shaft according to claim 1, characterized in that, The anti-loosening layer (4) is a thread lubrication and locking adhesive layer.

6. The bolt for assembling a double-coated drive shaft according to claim 5, characterized in that, The coating thickness of the thread lubrication and locking adhesive layer is 0.05-0.1 mm.

7. The bolt for assembling a double-coated drive shaft according to claim 1, characterized in that, The anti-loosening layer (4) has a coating width greater than that of the positioning layer (3), and the anti-loosening layer (4) near the head of the bolt body (1) is parallel to the positioning layer (3) near the head of the bolt body (1).

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