A lithium electric impact wrench for striking

Abstract

The present application provides a kind of lithium electric impact wrench for knocking, comprising the aluminum head shell and tail shell formed by snap-fit connection with installation cavity in the inside, shaft sleeve arranged in installation cavity and sleeved in the central hole of aluminum head shell, and output shaft sleeved in the inside of shaft sleeve, intermediate shaft assembly coaxially connected with output shaft is also arranged in installation cavity, gear box and wrench motor, a circle of snap spring slot is opened in output shaft, and snap spring is arranged in snap spring slot, shaft sleeve and aluminum head shell are integrally formed by pressure casting.The present application forms the fixed structure of impact wrench output shaft by installing snap spring on output shaft and integrally forming shaft sleeve and aluminum head shell by pressure casting, so that load force in the process of knocking is transmitted to aluminum head shell and shaft sleeve, which avoids force failure of output shaft and intermediate shaft assembly or avoids gear box cover to damage machine shell or gear box cover to break, thereby improving the overall impact resistance of impact wrench and prolonging the service life of impact wrench.

Description

Technical Field

[0001] This invention relates to the field of power tool technology, and more specifically, to a lithium-ion impact wrench for striking. Background Technology

[0002] When using conventional impact wrenches on the market, it is necessary to tighten or loosen bolts when encountering rusty bolts or bolts with foreign objects such as cement on their surface. Operators usually use the output shaft of the electric impact wrench head to knock away the cement foreign objects or rusty bolts, and then tighten or loosen the bolts.

[0003] However, during the impact, the axial force on the output shaft is transmitted to the intermediate shaft assembly, while the circumferential force is transmitted to the bushing. After being subjected to intermittent, prolonged impacts, the bushing can loosen from the aluminum head housing, causing the output shaft to jam with the intermediate shaft assembly, leading to product failure. The intermittent impact force, after being transmitted to the intermediate shaft assembly, is then transmitted through the assembly to the gasket, and finally to the bearing. The axial impact force transmitted through the bearing can cause the gearbox cover to damage the housing or shatter.

[0004] In view of this, there is an urgent need for a more reliable lithium-ion impact wrench for striking, in order to solve the technical problems existing in the striking process of existing lithium-ion impact wrenches. Summary of the Invention

[0005] This invention provides a lithium-ion impact wrench for striking, which solves the problem that lithium-ion impact wrenches are prone to damaging the gearbox cover housing or causing the gearbox cover to break when struck.

[0006] This invention provides a lithium-ion impact wrench for striking, comprising an aluminum head shell and a tail shell that are snapped together to form an internal mounting cavity, a bushing disposed in the mounting cavity and fitted into the central hole of the aluminum head shell, and an output shaft fitted inside the bushing. The mounting cavity also contains an intermediate shaft assembly, a gearbox, and a wrench motor coaxially connected to the output shaft. A retaining ring groove is formed on the output shaft, and a retaining ring is disposed in the retaining ring groove. The bushing and the aluminum head shell are integrally die-cast.

[0007] In some embodiments, the outer circumferential surface of the bushing is provided with an inner groove, and the inner ring of the aluminum head shell is provided with a ring of protrusions to fit the inner groove.

[0008] In some embodiments, the groove is specifically an I-shaped cross-section groove.

[0009] In some embodiments, a positioning sleeve is further included, which is circumferentially disposed in the gap between the aluminum head shell and the striking block.

[0010] In some embodiments, a gasket is further included, which is sleeved on the output shaft and disposed on the front end face of the aluminum head housing.

[0011] In some embodiments, an end face oil seal is also included, which covers the tail end face of the intermediate cover of the gearbox.

[0012] In some embodiments, the bearing positioned at the front end of the wrench motor is a stamped outer ring needle roller bearing, and the inner hole of the stamped outer ring needle roller bearing is positioned and fitted with the outer circle of the motor teeth.

[0013] In some embodiments, the positioning length between the stamped outer ring needle roller bearing and the motor teeth is 5mm to 9mm.

[0014] The lithium-ion impact wrench provided by this invention features a retaining ring groove on the output shaft, into which a retaining ring is installed. The bushing and aluminum head shell are integrally die-cast, forming a structure that secures the output shaft. When the impact wrench is used to strike bolts or other components, the striking force acting on the output shaft head is transmitted circumferentially to the integrally formed bushing and aluminum head shell assembly, and axially to the retaining ring. The retaining ring then limits the force and transmits it to the integrally formed bushing and aluminum head shell assembly. Thus, the load force during striking is transferred to the aluminum head shell and bushing, preventing failure of the output shaft and intermediate shaft assembly, and preventing the gearbox cover from damaging the housing or breaking. This improves the impact resistance of the impact wrench and extends its service life. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0016] Figure 1 A cross-sectional view of the lithium-ion impact wrench for striking provided by the present invention.

[0017] Figure 2 An exploded view of the lithium-ion impact wrench for striking provided by the present invention;

[0018] Figure 3 This is an assembly diagram of the bushing, aluminum head shell, output shaft, intermediate shaft assembly, positioning sleeve and striking block provided by the present invention;

[0019] Figure 4 for Figure 3 A schematic diagram of the mounting gasket at the front end of the alumina head shell;

[0020] Figure 5A schematic diagram of the intermediate shaft assembly, bearing, and motor gear provided by the present invention;

[0021] Figure 6 A schematic diagram of the intermediate shaft assembly, bearing, motor gear, and end face oil seal provided by the present invention;

[0022] Among them, 1-aluminum head shell, 2-tail shell, 3-shaft sleeve, 4-output shaft, 5-intermediate shaft assembly, 6-gearbox, 7-wrench motor, 8-circlip, 9-positioning sleeve, 10-shield, 11-end face oil seal, 12-bearing, 13-motor teeth, 14-striking block. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] This invention provides a lithium-ion impact wrench for striking, which mainly includes components such as an aluminum head shell 1, a tail shell 2, a bushing 3, an output shaft 4, an intermediate shaft assembly 5, a gearbox 6, and a wrench motor 7.

[0025] like Figure 1 and Figure 2 As shown. The aluminum head shell 1 and tail shell 2 are interlocked to form a shell structure with an internal mounting cavity. The bushing 3 is located in the mounting cavity and fitted into the central hole of the aluminum head shell 1. The front and rear end faces of the bushing 3 are flush with the front and rear end faces of the aluminum head shell 1, respectively. The output shaft 4 is located at the front end of the bushing 3 and fitted inside the bushing 3. An intermediate shaft assembly 5, coaxially connected to the output shaft 4, as well as a gearbox 6 and a wrench motor 7, are installed in the mounting cavity. For the specific structure, connection relationships, and working principles of the above components, please refer to existing technologies; this will not be elaborated upon here.

[0026] This invention employs a bushing 3 as an insert, integrally die-cast onto the aluminum head shell 1. A retaining ring groove is added to the output shaft 4 at the front end of the bushing 3, and a retaining ring 8, formed by bending flat steel wire, is installed within the retaining ring groove. When struck by the head of the output shaft 4, the circumferential force is directly transmitted to the integrally formed aluminum head shell assembly, ensuring that the aluminum head shell 1 and bushing 3 remain connected and do not loosen. The axial impact force is limited by the retaining ring 8, thus bearing the axial impact force and ensuring that the axial impact force is fully applied to the integrally formed aluminum head shell assembly. Furthermore, the aluminum head shell 1 can be reinforced with reinforcing ribs and increased thickness to fully withstand manual hammering loads, preventing damage to components.

[0027] Therefore, this invention optimizes the assembly structure of the output shaft 4 and bushing 3 of the impact wrench with the aluminum head shell 1, and adopts a method of fixing the impact wrench so that the load force it bears during the striking process is transferred to the aluminum head shell 1 and bushing 3, thereby solving the technical problem of the product's lack of durability during striking.

[0028] In one specific embodiment, the outer circumferential surface of the bushing 3 is provided with an inner groove, and the inner ring of the aluminum head shell 1 is provided with a raised structure. The raised structure fits into the inner groove to facilitate assembly and positioning, improving assembly accuracy and die-casting precision. Specifically, the inner groove is an I-shaped cross-section groove, and the raised structure of the inner ring of the aluminum head shell 1 is a rectangular raised structure with the same shape as the I-shaped cross-section groove. During die-casting, the raised structure of the inner ring of the aluminum head shell 1 is assembled with the inner groove of the bushing 3, and then die-casting is performed. The I-shaped structure ensures that the bushing and the aluminum head shell 1 do not separate or loosen, improving machining accuracy. The specific shapes of the inner groove and the raised structure can vary as long as they meet assembly requirements; this document does not impose any limitations.

[0029] like Figure 3 As shown. Furthermore, since there is a gap between the aluminum head shell 1 and the striking block 14, the circumferential force during the striking process can damage the gear due to the side load gap, and the circumferential force cannot be transmitted to the integrally formed aluminum head shell of the bushing. By adding a positioning sleeve 9 inside the gearbox, the positioning sleeve 9 is fitted into the gap between the aluminum head shell 1 and the striking block 14, which not only achieves auxiliary positioning, but also bears the circumferential striking force between the striking block 14 and the positioning sleeve 9, thus preventing product failure caused by the striking.

[0030] refer to Figure 4 Since the output shaft 4 is constantly rotating during operation, the flat steel wire bent and formed retaining spring 8 added to the output shaft 4 will inevitably rub against the integrally formed assembly of the bushing 3 and the aluminum head shell 1. This friction causes scratches on the product surface and generates frictional heat, affecting the user experience. To address this, a shim 10 is installed on the front end face of the aluminum head shell 1. The diameter of the shim 10 is larger than the outer diameter of the retaining spring 8, and the shim 10 can cover the bushing 3. The shim 10 mainly serves to reduce friction, preventing frictional heat and scratches on the surface of the bushing 3 caused by the added impact structure.

[0031] like Figure 5 As shown. During operation, the grease added to gearbox 6 is thrown out by centrifugal force, gradually accumulating and eventually leaking out through bearing 12, reaching the motor and switch positions. If the grease accumulates to a certain extent, it can cause the motor to fail to start when cold or result in poor contact in the switch signal line, leading to product failure. Currently, most impact wrenches on the market use O-rings or felt pads, but this method is not very effective in preventing oil leakage.

[0032] like Figure 6 As shown. In order to solve the problem of oil leakage at the connection between the impact wrench motor 7 and the gearbox 6, the present invention adopts a solution of installing an end face oil seal 11 on the tail end face of the middle cover of the gearbox 6, so that all the grease inside the gearbox 6 is completely blocked inside the gearbox 6 by the sealing of the end face oil seal 11.

[0033] Furthermore, the bearing 12 positioned at the front end of the wrench motor 7 was changed from a deep groove ball bearing to a stamped outer ring needle roller bearing. The inner hole of the stamped outer ring needle roller bearing is positioned and engaged with the outer circle of the motor gear 13. The stamped outer ring needle roller bearing is positioned inside the intermediate shaft assembly 5 using the clearance within the inner hole of the intermediate shaft assembly 5. Simultaneously, the engagement length between the motor gear 13 and the motor shaft is increased, allowing the inner hole of the stamped outer ring needle roller bearing to engage with the outer circle of the motor gear 13. The positioning length has increased from 5mm with the original deep groove ball bearing 12 to 9mm with the current stamped outer ring needle roller bearing without affecting positioning reliability. Based on this, an end face oil seal 11 is added in a shorter space, ensuring that all grease inside the gearbox 6 is completely blocked by the end face oil seal 11. This design achieves an oil leakage prevention structure within a smaller space, enabling a shorter overall machine length while maintaining reliable oil leakage prevention.

[0034] This invention solves the problem of the product's lack of durability during impact by fixing the output shaft 4 of the impact wrench, thus transferring the load force it bears during impact to the aluminum shell and bushing 3. Furthermore, by moving the front positioning bearing 12 of the wrench motor 7 forward and lengthening the engagement length of the motor teeth 13, and by adding a skeleton oil seal to the part of the motor coil above the iron core for sealing, this invention fully utilizes the limited internal space of the machine to achieve oil leakage prevention within a smaller space. This structure allows for a shorter overall length while achieving reliable oil leakage prevention and sealing. Its reasonable layout solves the oil leakage problem in existing solutions.

[0035] In summary, the lithium-ion impact wrench provided by this invention can withstand high-altitude impact operations, while also achieving miniaturization and oil-leakage prevention, thus meeting the high-temperature and long-term operation requirements of lithium-ion impact wrenches.

[0036] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0037] The lithium-ion impact wrench for striking provided by this invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this invention.

Claims

1. A lithium-ion impact wrench for striking, comprising an aluminum head shell (1) and a tail shell (2) that are snapped together to form an internal mounting cavity, a bushing (3) disposed in the mounting cavity and fitted into the central hole of the aluminum head shell (1), and an output shaft (4) fitted inside the bushing (3), wherein the mounting cavity is further provided with an intermediate shaft assembly (5), a gearbox (6), and a wrench motor (7) coaxially connected to the output shaft (4), characterized in that, A ring of retaining ring grooves is provided on the output shaft (4), and a retaining ring (8) is provided in the retaining ring grooves. The front and rear end faces of the bushing (3) are flush with the front and rear end faces of the aluminum head shell (1), respectively. The bushing (3) and the aluminum head shell (1) are die-cast integrally to form a fixing structure for the output shaft of the impact wrench. The retaining ring (8) is formed by bending flat steel wire. The aluminum head shell (1) bears the manual hammering load by means of reinforcing ribs and thickness reinforcement. When the impact wrench is used to strike the component, the striking force acting on the head of the output shaft (4) is transmitted circumferentially to the integrally formed bushing aluminum head shell assembly and axially to the retaining ring (8). The retaining ring (8) limits and bears the axial striking force and transmits it to the integrally formed bushing aluminum head shell assembly.

2. The lithium-ion impact wrench for striking according to claim 1, characterized in that, The outer circumferential surface of the bushing (3) is provided with an inner groove, and the inner ring of the aluminum head shell (1) is provided with a ring of protrusions to fit the inner groove.

3. The lithium-ion impact wrench for striking according to claim 2, characterized in that, The inner groove is specifically an I-shaped cross-section groove.

4. The lithium-ion impact wrench for striking according to any one of claims 1 to 3, characterized in that, It also includes a positioning sleeve (9) circumferentially disposed in the gap between the aluminum head shell (1) and the striking block (14).

5. The lithium-ion impact wrench for striking according to claim 4, characterized in that, It also includes a gasket (10) that is sleeved on the output shaft (4) and located on the front end face of the aluminum head shell (1).

6. The lithium-ion impact wrench for striking according to claim 4, characterized in that, It also includes an end face oil seal (11) on the tail end face of the intermediate cover of the gearbox (6).

7. The lithium-ion impact wrench for striking according to claim 1, characterized in that, The bearing (12) positioned at the front end of the wrench motor (7) is a stamped outer ring needle roller bearing, and the inner hole of the stamped outer ring needle roller bearing is positioned and fitted with the outer circle of the motor teeth (13).

8. The lithium-ion impact wrench for striking according to claim 7, characterized in that, The positioning length between the stamped outer ring needle roller bearing and the motor gear (13) is 5mm to 9mm.

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