Electric impact wrench output shaft structure
By setting a torque-reducing surface at the bottom of the output shaft to cooperate with the supporting slope of the impact block, combined with a T-shaped structure and precise torque transmission design, the problem of excessive torque caused by excessive impact force in traditional electric impact wrenches is solved, achieving more efficient energy utilization and tool stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- NANJING AIWEICHUANG ELECTRIC CO LTD
- Filing Date
- 2025-03-10
- Publication Date
- 2026-06-09
AI Technical Summary
The impact force generated by the striking block of a traditional electric impact wrench is too large, resulting in excessive torque transmitted to the output shaft. It is not suitable for low torque scenarios, easily damages the workpiece, and has low energy utilization efficiency.
A torque-reducing surface is set at the bottom of the output shaft to match the positioning protrusion support slope on the impact block. Combined with the T-shaped structure, torque protrusion and groove design, as well as the use of return spring and buffer steel ball, energy conversion and torque transmission are optimized.
It effectively reduces reverse torque, improves the safety and stability of tool operation, enhances energy utilization efficiency, extends tool life, reduces wear and noise, and ensures the accuracy and consistency of torque transmission.
Smart Images
Figure CN224334358U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the technical field of bolt tightening and loosening equipment, specifically relating to an output shaft structure for an electric impact wrench. Background Technology
[0002] Traditional electric impact wrenches use a motor to drive rotational motion and an internal striking mechanism to convert this motion into instantaneous impact torque for tightening or loosening nuts, bolts, and other fasteners with high strength. However, in actual use, when the output shaft is impacted by the striking block, a large reverse torque is generated. This can lead to instability in the tool's operation and potentially cause unnecessary damage to the fastened workpiece. Due to the lack of an effective energy conversion mechanism, some impact energy is not fully converted into usable torque output, resulting in low work efficiency. To improve torque output capability, some existing technologies employ complex mechanical structures, but this increases manufacturing costs and failure rates. Over long-term use, the direct contact between the striking block and the output shaft is prone to wear, affecting the tool's lifespan and accuracy.
[0003] Chinese Patent CN207373059U discloses an electric constant torque impact wrench, comprising a power mechanism, a coupling, and an output assembly arranged sequentially. The power mechanism includes a motor and a drive shaft driven by the motor. The drive shaft has an impact V-groove containing ball bearings. The end of the drive shaft away from the motor has a ratchet structure with the ratchet teeth inclined in the forward rotation direction. Rollers are arranged between adjacent teeth of the ratchet structure. This device generates excessive impact force and torque, making it unsuitable for applications requiring low torque and prone to damaging the workpiece. Therefore, a solution to these technical problems is urgently needed by those skilled in the art. Utility Model Content
[0004] The technical problem to be solved by this utility model is that in the above-mentioned prior art, the impact force generated by the striking block is too large, and the torque transmitted to the output shaft is too large, which is not suitable for low torque scenarios and is easy to damage the workpiece.
[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:
[0006] An output shaft structure for an electric impact wrench includes an impact block, an output shaft, a return spring, and a bushing. The output shaft is fitted onto the impact block, and the bushing is fitted onto the output shaft. The impact block has a positioning protrusion, and a supporting inclined surface is provided on one side of the top of the positioning protrusion. The bottom of the output shaft has a torque-reducing surface that matches the supporting inclined surface. The return spring is located inside the impact block.
[0007] By adopting the above technical solution, the impact block generates torque by striking the output shaft. The torque-reducing surface at the bottom of the output shaft contacts the support ramp on the positioning protrusion of the impact block. This reduces the force exerted by the impact block on the output shaft, thereby effectively reducing the reverse torque, improving the safety and stability of tool operation, and avoiding potential damage to the workpiece caused by excessive reverse torque. Due to the design of the torque-reducing surface and the support ramp, the energy during each impact can be more effectively converted into useful torque output, rather than wasted on unnecessary reaction forces. Therefore, the energy utilization efficiency of the entire system is significantly improved. The return spring inside the impact block can quickly return the impact block to its initial position after each impact, ensuring the consistency and accuracy of the next impact. In addition, the presence of the spring also plays a certain buffering role, reducing direct collisions between components and extending the tool's service life.
[0008] Furthermore, the output shaft has an overall T-shaped structure, and two torque-reducing surfaces are provided, located at both ends of the output shaft respectively.
[0009] By adopting the above technical solution, the T-shaped structure provides a wider support base, which helps to improve the stability of the entire system. When the output shaft rotates, the torque-reducing surfaces on both sides can evenly bear the pressure from the impact block, ensuring that the output shaft is always in the center position and reducing the possibility of deviation. The T-shaped structure increases the lateral stiffness of the output shaft, making it less prone to tilting or slipping under impact, thus ensuring the consistency and accuracy of torque transmission. Since the torque-reducing surfaces are located at both ends of the output shaft, the energy of each impact can be directly transmitted to the target position through the shortest path. This not only improves energy transmission efficiency but also reduces unnecessary energy loss, allowing each impact to be more effectively converted into useful torque output. The T-shaped structure design can better distribute the contact pressure between the impact block and the output shaft, reducing the situation of single-point concentrated force, thereby reducing the wear rate of components. At the same time, the other side of the torque-reducing surface is a vertical surface, so the positive torque of the electric impact wrench is not affected.
[0010] Furthermore, the striking block has a torque protrusion inside, and the output shaft has a torque groove that matches the torque protrusion.
[0011] By adopting the above technical solution, the matching design of the torque protrusion and torque groove ensures that the torque is accurately transmitted from the impact block to the output shaft with each impact, avoiding loss or deviation in the torque transmission process. This guarantees consistent and accurate operation of tightening or loosening nuts / bolts. Through this geometric matching, unnecessary sliding friction is reduced, allowing the energy of each impact to be more efficiently converted into useful torque output. This not only improves work efficiency but also reduces the tool's operating temperature and extends its service life. The matching of the torque protrusion and groove effectively limits the relative rotation between the impact block and the output shaft, ensuring that they always maintain the correct alignment. Even under high-load working conditions, stable working performance is maintained, reducing the risk of failure due to component misalignment. Compared to direct contact, the design of the torque protrusion and groove can better disperse stress during impact, reducing local stress concentration and thus reducing the possibility of wear and damage. With long-term use, this design helps maintain the tool's good condition and extend its service life. Because the torque transmission is more precise and smooth, users will feel less vibration and impact reaction force during operation, improving operating comfort and reducing fatigue during long-term work.
[0012] Furthermore, the top of the reset spring is mounted inside the striking block via a spring pad, and the spring pad is provided with a buffer steel ball.
[0013] By adopting the above technical solution, the presence of the buffer steel ball effectively cushions each impact, absorbing some of the impact energy and thus reducing noise and vibration generated during tool operation. This not only improves operational comfort but also reduces the potential health impact on users from long-term use. The combination of the spring pad and the buffer steel ball ensures that the return spring smoothly returns to its initial position after each compression. This stable return process helps maintain precise fit between the striking block and the output shaft, thereby improving the consistency and accuracy of torque transmission. The buffer steel ball effectively disperses the contact pressure between the top of the return spring and the inner surface of the striking block, reducing direct metal-to-metal friction. This design reduces the wear rate and extends the service life of the return spring, spring pad, and striking block itself. The rolling characteristics of the buffer steel ball allow it to move flexibly under pressure, avoiding component jamming caused by friction or adhesion. This ensures the reliability and stability of the tool under high-intensity working environments. Through the effective cushioning of the buffer steel ball, unnecessary energy loss is reduced, allowing the energy of each impact to be more efficiently converted into useful torque output. This not only improves work efficiency but also reduces the tool's operating temperature, further extending its service life. The cushioning steel balls play a certain role in shock absorption during impact, helping to mitigate the effects of reverse torque. This reduces the risk of damage to the workpiece and the tool itself, which is especially important when handling high-hardness or sensitive materials.
[0014] Further, a sealing ring is also provided at the top of the bushing.
[0015] Further, the torque protrusions are in a "human" shape, and there are two torque protrusions in total, which are located on both sides of the top of the striking block.
[0016] The utility model has the following beneficial effects:
[0017] 1. By providing a torque-reducing surface at the bottom of the output shaft and matching it with the supporting inclined surface of the positioning protrusion on the striking block, during each impact, the torque-reducing surface slides along the supporting inclined surface, reducing the force exerted by the striking block on the output shaft, effectively reducing the reverse torque, and avoiding potential damage to the workpiece caused by excessive reverse torque. The top of the return spring abuts against the inside of the striking block through a spring pad, and buffer steel balls are provided on the spring pad to further absorb part of the impact energy, reduce unnecessary reaction forces and vibrations, and improve the safety and stability of tool operation;
[0018] 2. By matching the torque protrusions provided inside the striking block with the torque grooves on the output shaft, it ensures that the torque can be accurately transmitted from the striking block to the output shaft during each impact, avoiding losses or deviations during the torque transmission process, reducing sliding friction, enabling the energy of each impact to be more efficiently converted into useful torque output. The output shaft is of a T-shaped structure as a whole, and a torque-reducing surface is provided at each end. This design not only provides a wider support base, enhances the stability of the system, but also enables the energy of each impact to be directly transmitted to the target position through the shortest path, improving the energy transmission efficiency while maintaining the effective transmission of the forward torque;
[0019] 3. The presence of the torque protrusions, torque grooves and buffer steel balls in the utility model can better disperse the stress generated during the impact process, reduce the situation of local stress concentration, thereby reducing the possibility of wear and damage, helping to maintain the good condition of the tool and extending its service life. The design of the spring pad and buffer steel balls makes the return spring easier to install and拆卸, facilitating daily maintenance and repair. The setting of the sealing ring further improves the sealing performance and dust and waterproof performance of the system, ensuring that the internal mechanism works in a clean and dry environment, and indirectly increasing the durability of the product. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 is a three-dimensional structural schematic diagram of the utility model;
[0021] Figure 2 is a structural schematic diagram of the striking block of the utility model;
[0022] Figure 3 is Figure 1Enlarged diagram of section A in the middle;
[0023] Figure 4 This is a schematic diagram of the output shaft of this utility model.
[0024] Among them, 1-output shaft; 11-torque reduction surface; 12-torque groove; 2-impact block; 21-positioning protrusion; 211-support slope; 22-torque protrusion; 3-shaft sleeve; 4-reset spring; 41-spring pad; 42-buffer steel ball; 5-sealing ring. Detailed Implementation
[0025] The present invention will now be described in further detail with reference to the accompanying drawings and specific preferred embodiments.
[0026] In the description of this utility model, it should be understood that the terms "left side," "right side," "upper part," "lower part," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. "First," "second," etc., do not indicate the importance of the components, and therefore should not be construed as a limitation of this utility model. The specific dimensions used in this embodiment are only for illustrating the technical solution and do not limit the protection scope of this utility model.
[0027] like Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, an output shaft structure for an electric impact wrench aims to solve the problems in the prior art where the impact force generated by the striking block 2 is too large and the reverse torque transmitted to the output shaft 1 is too large, making it unsuitable for low-torque scenarios. The structure includes the striking block 2, the output shaft 1, the return spring 4, and the bushing 3. The striking block 2, as the main impact-generating component, has the return spring 4 internally and a positioning protrusion 21 externally. A supporting inclined surface 211 is provided on one side of the top of the positioning protrusion 21 for cooperating with the torque-reducing surface 11 of the output shaft 1. The output shaft 1 is mounted on the impact block 2. Its bottom has a torque-reducing surface 11 that matches the supporting inclined surface 211, ensuring that the torque-reducing surface slides along the supporting inclined surface during each impact, reducing the force applied to the output shaft by the impact block 2. The output shaft 1 has a T-shaped structure with a torque-reducing surface 11 at each end. This design provides a wider support base and enhances the stability of the device. The impact block 2 has two V-shaped torque protrusions 22 located on both sides of its top. Correspondingly, the output shaft 1 has torque grooves 12 that match the torque protrusions 22, ensuring that the torque is accurately transmitted from the impact block to the output shaft 1 during each impact, avoiding loss or deviation during torque transmission, and guaranteeing the consistency and accuracy of tightening or loosening nuts / bolts. Furthermore, the top of the return spring 4 abuts against the inside of the impact block 2 via a spring washer 41. The spring washer 41 has a buffer steel ball 42, which quickly returns the impact block 2 to its initial position after each impact, ensuring the consistency and accuracy of the next impact. Meanwhile, the buffer steel ball 42 absorbs some of the impact energy, reducing the noise and vibration generated when the tool is working. The bushing 3 is fitted onto the output shaft 1, and a sealing ring 5 is set on the top, which enhances the sealing and dustproof and waterproof capabilities of the entire device, ensuring that the internal mechanism works in a clean and dry environment, and indirectly increasing the durability of the product.
[0028] Working principle: First, the torque-reducing surface 11 mates with the supporting inclined surface 211. The impact block 2 has a positioning protrusion 21 on its exterior, and a supporting inclined surface 211 on one side of its top. The bottom of the output shaft 1 has a torque-reducing surface 11 that matches the supporting inclined surface 211. During each impact, the torque-reducing surface 11 of the output shaft 1 slides along the supporting inclined surface 211 of the impact block 2. This design reduces the force exerted by the impact block on the output shaft, thereby significantly reducing the reverse torque. In this way, the impact force can be more effectively converted into useful torque output, rather than wasted on unnecessary reaction force.
[0029] Secondly, the output shaft 1 has a T-shaped structure with a torque-reducing surface 11 at each end. This design provides a wider support base, enhances the stability of the device, and allows the energy of each impact to be directly transferred to the target position through the shortest path, improving energy transfer efficiency. Since the torque-reducing surfaces 11 are located at both ends of the output shaft 1, the energy of each impact can be more effectively converted into useful torque output, further reducing the influence of reverse torque.
[0030] Furthermore, the impact block 2 has two V-shaped torque protrusions 22 located on both sides of its top; corresponding torque grooves 12 are provided on the output shaft 1 to match the torque protrusions 22. This geometric matching ensures that the torque is accurately transmitted from the impact block 2 to the output shaft 1 with each impact, avoiding loss or deviation during torque transmission. Precise torque transmission not only improves work efficiency but also reduces reverse torque fluctuations caused by inconsistent torque transmission.
[0031] Meanwhile, the top of the return spring 4 abuts against the inside of the impact block 2 via a spring washer 41, on which a buffer steel ball 42 is mounted. After each impact, the return spring 4 quickly returns the impact block to its initial position, ensuring the consistency and accuracy of the next impact. The buffer steel ball 42 absorbs part of the impact energy, reducing noise and vibration generated during tool operation, effectively mitigating the impact of reverse torque on the output shaft 1, and further reducing the risk of reverse torque.
[0032] Finally, bushing 3 is fitted onto output shaft 1, with a sealing ring 5 on top, enhancing the overall sealing and dust and water resistance of the device. This not only ensures that the internal mechanism operates in a clean and dry environment, indirectly increasing the product's durability, but also reduces the impact of external factors on internal mechanical components, maintaining system stability and reliability, and helping to maintain a low level of reverse torque.
[0033] In summary, this invention successfully achieves a significant reduction in reverse torque by optimizing the connection relationships and functions between various components. The cooperation between the torque-reducing surface 11 and the supporting inclined surface 211 reduces the impact force directly acting on the output shaft 1. The design of the T-shaped output shaft 1 and the double torque-reducing surfaces 11 ensures that the energy of each impact is efficiently converted into useful torque output. The precise torque transmission mechanism improves working efficiency and reduces reverse torque fluctuations, while the effective buffering mechanism and good sealing performance further enhance the stability and reliability of the system.
[0034] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and all such equivalent transformations fall within the protection scope of the present invention.
Claims
1. An output shaft structure for an electric impact wrench, characterized in that: It includes a striking block (2), an output shaft (1), a return spring (4) and a bushing (3); the output shaft (1) is sleeved on the striking block (2), the bushing (3) is sleeved on the output shaft (1), a positioning protrusion (21) is provided on the striking block (2), a support inclined surface (211) is provided on one side of the top of the positioning protrusion (21), a torque-reducing surface (11) adapted to the support inclined surface (211) is provided at the bottom of the output shaft (1), and the return spring (4) is provided inside the striking block (2).
2. The electric impact wrench output shaft structure according to claim 1, characterized in that: The output shaft (1) is of an overall T-shaped structure, and two torque-reducing surfaces (11) are provided, respectively located at both ends of the output shaft (1).
3. The electric impact wrench output shaft structure according to claim 2, characterized in that: Torque protrusions (22) are provided inside the striking block (2), and torque grooves (12) adapted to the torque protrusions (22) are provided on the output shaft (1).
4. The electric impact wrench output shaft structure according to claim 3, characterized in that: The top of the return spring (4) abuts against the inside of the striking block (2) through a spring pad (41), and buffer steel balls (42) are provided on the spring pad (41).
5. The output shaft structure of the electric impact wrench according to claim 1, characterized in that: A sealing ring (5) is further provided at the top of the bushing (3).
6. The output shaft structure of the electric impact wrench according to claim 3, characterized in that: The torque protrusions (22) are of a "human" shape, two torque protrusions (22) are provided, and the torque protrusions (22) are located on both sides of the top of the striking block (2).