Electric wrench

Abstract

The utility model relates to an electric wrench, the output torque of which is greater than or equal to 2000N. M. The electric wrench comprises a motor, which comprises a rotor shaft; the NW type gear transmission assembly comprises a planet wheel, an inner gear ring, a planet carrier and a sun wheel formed at the front end of the rotor shaft; the front bearing and the rear bearing are connected to the periphery of the rotor shaft in a sleeving mode and located on the front side and the rear side of a main body shell of the motor respectively; the auxiliary supporting bearing is connected to the periphery of the rotor shaft in a sleeving mode and located between the sun gear and the front bearing; the gear box is used for containing the NW type gear transmission assembly, and the maximum distance between the central axis of the gear box and the outer wall of the gear box is smaller than or equal to 60 mm. According to the electric wrench, the output torque is larger than or equal to 2000 N.m, the maximum distance between the central axis of the gearbox and the outer wall of the gearbox is smaller than or equal to 60 mm, and the whole wrench runs stably.

Description

Technical Field

[0001] The utility model relates to the technical field of electric tools, in particular to an electric wrench. Background Art

[0002] An electric wrench is a tool for tightening and loosening bolts and nuts. Currently, some electric wrenches use a single-stage planetary gear system to reduce the speed of the motor rotor, typically employing an NGW gear train with a narrow transmission ratio range. The motor's rotor shaft is supported by two bearings, front and rear. The axial spacing between the sun gear and the front bearing in the NGW gear train is small, resulting in smoother transmission. Compared to the NGW gear system, the NW gear system offers higher transmission efficiency and a wider transmission ratio range, but its axial dimensions are larger. If used in an electric wrench, this increases the axial spacing between the front bearing and the sun gear of the NW gear system, leading to unstable transmission. Utility Model Content

[0003] Based on the above-mentioned defects in the prior art, the purpose of the present invention is to provide an electric wrench with an output torque greater than or equal to 2000 N·m, a maximum distance between the central axis of the gear box and its outer wall less than or equal to 60 mm, and stable operation of the entire machine.

[0004] To this end, the present invention provides the following technical solutions.

[0005] The utility model provides an electric wrench, the output torque of the electric wrench is greater than or equal to 2000 N·m, and the electric wrench comprises:

[0006] an electric motor comprising a rotor shaft;

[0007] An NW type gear transmission assembly comprising planetary gears, an inner ring gear, a planetary carrier and a sun gear formed at the front end of the rotor shaft;

[0008] A front bearing and a rear bearing, both of which are respectively sleeved on the outer circumference of the rotor shaft and are respectively located on the front side and the rear side of the main body housing of the motor;

[0009] an auxiliary support bearing, sleeved on the outer periphery of the rotor shaft and located between the sun gear and the front bearing;

[0010] A gear box is used to accommodate the NW-type gear transmission assembly, and the maximum distance between the central axis of the gear box and its outer wall is less than or equal to 60 mm.

[0011] Optionally, one end of the planet carrier is provided with an axially extending cavity and a radially extending first mounting groove, the planet gear is mounted in the first mounting groove, and the front end of the rotor shaft is inserted into the cavity and meshes with the planet gear.

[0012] Optionally, the auxiliary support bearing is mounted on the planet carrier.

[0013] Optionally, the auxiliary support bearing is mounted in the concave cavity.

[0014] Optionally, a cavity wall of the concave cavity is provided with a boss, and the auxiliary support bearing is axially abutted against the boss.

[0015] Optionally, the boss is located between the first mounting groove and the auxiliary support bearing.

[0016] Optionally, the boss is annular.

[0017] Optionally, a second mounting groove is provided at the rear end of the gear box, and the front bearing is mounted in the second mounting groove.

[0018] Optionally, an annular protrusion is provided on the rear end surface of the gear box, and the second mounting groove is formed between the annular protrusion and the rear end surface of the gear box.

[0019] Optionally, the axial dimension of the auxiliary support bearing is smaller than the axial dimension of the front bearing.

[0020] The utility model has the following technical effects:

[0021] The utility model provides an electric wrench that utilizes an NW-type gear transmission assembly to increase output torque, achieving an output torque greater than or equal to 2000 N·m. Furthermore, the NW-type gear transmission assembly has a smaller radial dimension than an NGW gear train, thereby enabling the maximum distance between the central axis of the gearbox and its outer wall to be less than or equal to 60 mm, facilitating the miniaturization of the radial dimension of the electric wrench. Furthermore, the electric wrench incorporates an auxiliary support bearing positioned between the sun gear and the front bearing to support the rotor shaft, thereby reducing or preventing deformation of the front portion of the rotor shaft. This avoids the resulting unstable meshing between the sun gear and the planetary gears, preventing the electric wrench from operating smoothly under adverse operating conditions, thereby ensuring smooth operation of the entire machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a structural sectional view of the electric wrench of the utility model;

[0023] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0024] Figure 3 This is an exploded view of the local structure of the electric wrench of the utility model;

[0025] Description of Reference Numerals

[0026] 100. Electric wrench;

[0027] 1. Motor; 11. Rotor shaft;

[0028] 2. NW-type gear transmission assembly; 21. planetary gear; 22. inner ring gear; 23. planetary carrier; 231. cavity; 2311. boss; 232. first mounting slot; 24. sun gear; 25. planetary pin;

[0029] 3. Front bearing;

[0030] 4. Rear bearing;

[0031] 5. Auxiliary support bearing;

[0032] 6. Gear box; 61. Annular protrusion. DETAILED DESCRIPTION

[0033] To make the technical solutions and beneficial effects of the present invention more clearly understood, the following describes the present invention in detail by listing specific embodiments. Unless otherwise defined, the technical and scientific terms used herein have the same meanings as those in the technical field to which this application belongs.

[0034] In the description of the present invention, unless otherwise expressly defined, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "height", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of simplifying the description of the present invention, and do not indicate that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and should not be understood as a limitation to the present invention.

[0035] In this utility model, the terms "first" and "second" are used solely for descriptive clarity and should not be construed as indicating the relative importance of the features indicated or the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly include at least one such feature. In the description of this utility model, "plurality" means at least two, and "several" means at least one, unless expressly specified otherwise.

[0036] In this utility model, unless otherwise expressly defined, the terms "install," "connect," "connect," "fix," "dispose," etc. should be understood broadly. For example, "connection" can mean fixed connection, detachable connection, or integral molding; it can be mechanical or electrical; it can be direct connection or indirect connection through an intermediary; it can also refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of these terms in this utility model based on the specific circumstances.

[0037] In the present invention, unless otherwise clearly defined, when a first feature is “on,” “above,” “above,” “above,” “below,” “below,” or “below” a second feature, the first feature and the second feature may be in direct contact, or the first feature and the second feature may be in indirect contact via an intermediate medium. Moreover, when a first feature is “on,” “above,” or “above” a second feature, it may mean that the first feature is directly above or obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than the horizontal height of the second feature. When a first feature is “below,” “below,” or “below” a second feature, it may mean that the first feature is directly below or obliquely below the second feature, or simply means that the horizontal height of the first feature is lower than the horizontal height of the second feature.

[0038] The "front" and "back" mentioned in this utility model are Figure 1 The markings in the table shall prevail.

[0039] The following is based on Figures 1 to 3 The electric wrench of the utility model is described in detail.

[0040] In this embodiment, if Figures 1 to 3As shown, the electric wrench 100 includes a motor 1, an NW-type gear transmission assembly 2, a front bearing 3, a rear bearing 4, an auxiliary support bearing 5, and a gearbox 6. The motor 1 includes a rotor shaft 11 for outputting a rotational driving force. The NW-type gear transmission assembly 2 is disposed within the gearbox 6, and the NW-type gear transmission assembly 2 is located in front of the motor 1. The NW-type gear transmission assembly 2 includes planetary gears 21, an inner ring gear 22, a planetary carrier 23, and a sun gear 24 formed at the front end of the rotor shaft 11. The planetary gears 21 are mounted on the planetary carrier 23 and mesh with the inner ring gear 22 and the sun gear 24, respectively. The output torque of the electric wrench 100 is greater than or equal to 2000 N·m. The maximum distance between the central axis of the gearbox 6 and its outer wall is less than or equal to 60 mm. It should be understood that the outer wall of the gearbox 6 does not include the surface wall of the fastening screws mounted on the gearbox 6. The front bearing 3 and the rear bearing 4 are respectively sleeved on the outer circumference of the rotor shaft 11 and are located on the front and rear sides of the main housing of the motor 1, respectively, to support the rotor shaft 11. The auxiliary support bearing 5 is sleeved on the outer circumference of the rotor shaft 11 and is located between the sun gear 24 and the front bearing 3.

[0041] By adopting the above technical solution, the electric wrench 100 adopts an NW-type gear transmission assembly 2, which has higher transmission efficiency and a wider transmission ratio range than the NGW gear system, and can increase the output torque of the electric wrench 100, so that the output torque of the electric wrench 100 is greater than or equal to 2000 N·m. In addition, the NW-type gear transmission assembly 2 has a smaller radial dimension than the NGW gear system, and thus can make the maximum distance between the central axis of the gear box 6 and the outer wall thereof less than or equal to 60 mm, which is conducive to the miniaturization design of the radial dimension of the electric wrench 100. In addition, since the axial dimension of the NW-type gear transmission assembly 2 is larger than that of the NGW gear system, the axial spacing between the front bearing 3 and the sun gear 24 is longer, resulting in unstable transmission. In this solution, the electric wrench 100 is additionally provided with an auxiliary support bearing 5. The auxiliary support bearing 5 is positioned between the sun gear 24 and the front bearing 3 to support the rotor shaft 11, thereby reducing the deformation amplitude of the front part of the rotor shaft 11 or preventing the front part of the rotor shaft 11 from deforming. This can avoid the unstable engagement between the sun gear 24 and the planetary gear 21 caused by this, and avoid the electric wrench 100 from failing to work smoothly under harsh working conditions, that is, ensuring the smooth operation of the entire machine.

[0042] In one embodiment, if Figure 2 and Figure 3As shown, one end of the planet carrier 23 is provided with an axially extending concave cavity 231 and a radially extending first mounting groove 232. The concave cavity 231 and the first mounting groove 232 are in communication. The planet gears 21 are mounted in the first mounting groove 232. The front end of the rotor shaft 11 is inserted into the concave cavity 231 and meshes with the planet gears 21. In one embodiment, there are two planet gears 21. The first mounting groove 232 radially extends through the main body of the planet carrier 23. The two planet gears 21 are located on either side of the sun gear 24 in the radial direction and are mounted to the planet carrier 23 via planet pins 25.

[0043] Furthermore, the auxiliary support bearing 5 is mounted on the planet carrier 23 .

[0044] Furthermore, if Figure 2 As shown, the auxiliary support bearing 5 is installed in the cavity 231 , and the internal space of the cavity 231 is used to accommodate the auxiliary support bearing 5 , thereby avoiding increasing the size of the electric wrench 100 due to the provision of the auxiliary support bearing 5 .

[0045] Furthermore, if Figure 2 As shown, the cavity wall of the concave cavity 231 is provided with a boss 2311, the outer ring of the auxiliary support bearing 5 radially abuts against the cavity wall of the concave cavity 231 and axially abuts against the boss 2311, and the inner ring of the auxiliary support bearing 5 is sleeved on the rotor shaft 11. The auxiliary support bearing 5 is easy and firm to assemble.

[0046] Furthermore, if Figure 2 and Figure 3 As shown, the boss 2311 is located between the first mounting groove 232 and the auxiliary support bearing 5. Thus, when assembling the auxiliary support bearing 5, the auxiliary support bearing 5 is inserted from the open end of the cavity 231 of the planetary carrier 23 until it abuts against the boss 2311, facilitating assembly. Of course, the position of the boss 2311 is not limited to this. The auxiliary support bearing 5 can also be located between the boss 2311 and the first mounting groove 232. Thus, when assembling the auxiliary support bearing 5, the auxiliary support bearing 5 is inserted from the first mounting groove 232 into the cavity 231 until it abuts against the boss 2311, completing assembly. However, assembly is slightly inconvenient.

[0047] Furthermore, the boss 2311 is annular, which is conducive to stable axial abutment against the auxiliary support bearing 5.

[0048] In one embodiment, a second mounting groove (not shown) is provided at the rear end of the gear box 6 , and the front bearing 3 is mounted in the second mounting groove, which facilitates assembly.

[0049] Furthermore, if Figure 2 As shown, the rear end surface of the gear box 6 is provided with an annular protrusion 61, and a second mounting groove is formed between the annular protrusion 61 and the rear end surface of the gear box 6, which is easy to process.

[0050] In one embodiment, if Figure 2 and Figure 3 As shown, the axial dimension of the auxiliary support bearing 5 is smaller than the axial dimension of the front bearing 3. In this way, the front part of the rotor shaft 11 is supported by the auxiliary support bearing 5, which stabilizes the operation of the entire machine. At the same time, it also avoids the auxiliary support bearing 5 being difficult to assemble due to its long axial dimension, or even causing the axial dimension of the entire electric wrench 100 to increase.

[0051] It should be understood that the above embodiments are exemplary and are not intended to encompass all possible implementations of the claims. Various modifications and variations may be made to the above embodiments without departing from the scope of the present disclosure. Similarly, the various technical features of the above embodiments may be arbitrarily combined to form additional embodiments of the present invention that may not be explicitly described. Therefore, the above embodiments merely illustrate several implementations of the present invention and do not limit the scope of protection of the present utility model patent.

Claims

1. An electric wrench, characterized in that: The output torque of the electric wrench (100) is greater than or equal to 2000 N·m, and the electric wrench (100) comprises: An electric motor (1) comprising a rotor shaft (11); An NW-type gear transmission assembly (2), comprising planetary gears (21), an inner ring gear (22), a planetary carrier (23), and a sun gear (24) formed at the front end of the rotor shaft (11); A front bearing (3) and a rear bearing (4), both of which are respectively sleeved on the outer periphery of the rotor shaft (11) and are respectively located on the front side and the rear side of the main housing of the motor (1); an auxiliary support bearing (5) sleeved on the outer periphery of the rotor shaft (11) and located between the sun gear (24) and the front bearing (3); A gear box (6) is used to accommodate the NW-type gear transmission assembly (2), and the maximum distance between the central axis of the gear box (6) and its outer wall is less than or equal to 60 mm.

2. The electric wrench according to claim 1, characterized in that: One end of the planet carrier (23) is provided with an axially extending concave cavity (231) and a radially extending first mounting groove (232); the planet gear (21) is mounted in the first mounting groove (232); and the front end of the rotor shaft (11) is inserted into the concave cavity (231) and meshes with the planet gear (21).

3. The electric wrench according to claim 2, characterized in that: The auxiliary support bearing (5) is mounted on the planet carrier (23).

4. The electric wrench according to claim 3, characterized in that: The auxiliary support bearing (5) is installed in the concave cavity (231).

5. The electric wrench according to claim 4, characterized in that: The cavity wall of the concave cavity (231) is provided with a boss (2311), and the auxiliary support bearing (5) is axially abutted against the boss (2311).

6. The electric wrench according to claim 5, characterized in that: The boss (2311) is located between the first mounting groove (232) and the auxiliary support bearing (5).

7. The electric wrench according to claim 5, characterized in that: The boss (2311) is annular.

8. The electric wrench according to any one of claims 1 to 7, characterized in that: A second mounting groove is provided at the rear end of the gear box (6), and the front bearing (3) is mounted in the second mounting groove.

9. The electric wrench according to claim 8, characterized in that: An annular protrusion (61) is provided on the rear end surface of the gear box (6), and the second mounting groove is formed between the annular protrusion (61) and the rear end surface of the gear box (6).

10. The electric wrench according to any one of claims 1 to 7, characterized in that: The axial dimension of the auxiliary support bearing (5) is smaller than the axial dimension of the front bearing (3).

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