Electric wrench

Abstract

The utility model discloses an electric wrench which comprises a shell, a driving device, a reversing device, a transmission device, a working device and an observation device. The reversing device and the working device are rotationally mounted in the shell and are connected in sequence; the shell is divided into an upper shell and a lower shell; the driving device is installed on a handheld handle and a limiting plate of the lower shell, serves as a power source and control of the whole and can control the working device to rotate forwards and backwards; the upper end and the lower end of the reversing device are respectively meshed with the driving device and the transmission device, so that the change of a power transmission plane is realized; the transmission devices are symmetrically installed on the two sides of the central axis of the lower shell, the transmission devices are power transmission of the working device, the power transmission effect is achieved, and continuous rotation of the working device is guaranteed. The working device is mounted in the groove of the lower shell and can rotate in the groove; the observation device is installed on the front end face of the upper shell. The device is simple to operate and can be used in a narrow space or an occasion which is difficult to observe by naked eyes.

Description

Technical Field

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

[0002] Wrenches are widely used in daily life and engineering fields, and are usually used to tighten or loosen screws and nuts. Wrenches are mainly divided into two types: open-end wrenches and ratchet wrenches. When using an open-end wrench, the nut to be tightened or loosened needs to be placed in the opening of the wrench, and the two end faces of the nut need to be placed against the two end faces of the wrench. After each rotation of a certain angle, the opening position of the wrench needs to be adjusted, and then the operation is repeated. The operation process is cumbersome and requires a large operating space. This type of wrench is not easy to use in a small space; the wrench mouth of the ratchet wrench is closed, and when in use, only the nut needs to be placed in the wrench mouth and rotated, but the ratchet wrench requires a larger operating space; whether it is an open-end wrench or a ratchet wrench, it needs to be used in a place that can be directly observed by the naked eye, and in actual engineering applications, a wrench may also be used to operate in some places that are difficult to observe with the naked eye. In order to improve work efficiency and broaden the use of occasions, and to make up for the shortcomings of ordinary wrenches, it is necessary to invent an electric wrench that can be used in a small space and in places where threaded parts cannot be directly observed with the naked eye. Summary of the invention

[0003] In view of this, the utility model provides an electric wrench which can be used in a narrow space or a place which cannot be directly observed by naked eyes.

[0004] In order to achieve the above-mentioned purpose, the utility model proposes an electric wrench, which includes: a housing, a driving device, a reversing device, a transmission device, a working device and an observation device; the reversing device and the working device are all installed inside the housing and connected in sequence and can make a rotating motion in the housing; the housing is divided into an upper housing and a lower housing, the upper housing is a hollow structure, the lower housing includes a hand-held handle, a limit plate and a base, the limit plate is provided with a stepped cylindrical hole, the base is provided with five stepped cylindrical holes from back to front, the upper housing is provided with four stepped cylindrical holes from back to front for installing a positioning support component, and a groove is also provided on the front end surface of the base for accommodating the working device; the driving device is installed on the hand-held handle and On the limit plate, the driving device serves as the overall power source and control, which can control the forward and reverse rotation of the working device, thereby realizing the tightening and loosening of the threaded parts; the upper and lower ends of the reversing device are respectively meshed and connected with the driving device and the transmission device, realizing the change of the power transmission plane; the transmission device is symmetrically installed on both sides of the central axis of the lower shell, and the transmission device is the power transmission of the working device, which not only plays a role in power transmission but also ensures the continuous rotation of the working device, thereby improving work efficiency; the working device is installed in the groove of the lower shell and can rotate in the groove; the observation device is fixedly installed on the front end face of the upper shell, and can accurately find the position of the threaded parts and perform operations in situations where it is difficult to observe with the naked eye.

[0005] Furthermore, the driving device includes: a controller, a driving motor, a coupling, a bearing a, a gear shaft a, a flat key a and a flat key b; the controller and the driving motor are fixedly mounted on the hand-held handle of the lower shell; the gear shaft a is rotatably mounted on the limit plate, and the left end face of the gear shaft a is provided with a cylindrical boss; the bearing a is rotatably mounted in the stepped cylindrical hole of the limit plate, the left end of the bearing a is stuck in the step of the stepped cylindrical hole, and the right end is slidably connected to the gear shaft a; the left end of the coupling is slidably connected to the driving motor via a flat key a, and the right end is slidably connected to the gear shaft a via a flat key b.

[0006] Furthermore, the controller includes: a switching switch and a main switch; the switching switch is fixed on the right side of the hand-held handle, and the switching switch is electrically connected to the drive motor and the observation device; the main switch is fixedly installed on the upper surface of the hand-held handle, and the main switch is electrically connected to the drive motor. The main switch has three gears. When it is placed in the middle gear, the drive motor does not rotate; when it is placed in the front gear, the drive motor rotates forward; when it is placed in the rear gear, the drive motor rotates reversely.

[0007] Furthermore, the reversing device comprises: a face gear shaft, a spur gear, a bearing b, a flat key c and a sleeve; the bearing b is rotatably installed in the stepped cylindrical hole of the base, the lower end face of the bearing b is limited at the step of the stepped cylindrical hole, and the inner ring of the bearing b at the upper end face contacts the sleeve; the lower shaft end of the face gear shaft is rotatably installed in the bearing b of the base, and a keyway is provided on the shaft of the face gear shaft; the spur gear is slidably connected to the face gear shaft through the flat key c, and a groove is provided in the inner hole of the spur gear; the flat key c is installed in the keyway of the face gear shaft, and the upper end face of the flat key c fits with the groove of the inner hole of the spur gear; the sleeve is installed between the bearing b and the spur gear to limit the axial movement of the spur gear; the face gear in the face gear shaft is meshed with the gear shaft a in the driving device.

[0008] Furthermore, the transmission device includes: a gear shaft b, a gear shaft c, a gear shaft d, a gear shaft e and four pairs of bearings for positioning support; the gear shaft b and the gear shaft c as well as the gear shaft d and the gear shaft e are symmetrically installed on the base along the central axis of the lower shell, wherein the gear shaft b and the gear shaft c are both meshed and connected with the spur gears in the reversing device, and the gear shaft d and the gear shaft e are respectively meshed and connected with the gear shaft b and the gear shaft c, and the upper shaft ends and lower shaft ends of the above four gear shafts are provided with cylindrical bosses; the four pairs of bearings in the transmission device are respectively installed in the stepped cylindrical holes of the upper shell and the base, wherein the inner gear rings on one end faces of the four pairs of bearings are in contact with the cylindrical bosses of the four gear shafts, so that the four gear shafts only retain rotational freedom between the upper shell and the lower shell.

[0009] Furthermore, the four pairs of bearings are respectively installed in the stepped cylindrical holes of the upper shell and the base. Since the structure and installation method of the four pairs of bearings are the same, bearings C and bearings D used for positioning and supporting gear shaft b are used as examples for explanation. The outer gear ring of the upper end face of bearing c is stuck in the step of the stepped cylindrical hole of the upper shell, and the inner gear ring of the lower end face of bearing c is in contact with the cylindrical boss of the upper shaft end of gear shaft b. The outer gear ring of the lower end face of bearing d is stuck in the step of the stepped cylindrical hole of the base, and the inner gear ring of the upper end face of bearing d is in contact with the cylindrical boss of the lower shaft end of gear shaft b.

[0010] Furthermore, the working device includes an open gear and a nut sleeve; the open gear is rotatably installed on the base, and a boss is provided on the lower end face of the open gear, and the boss of the open gear fits with the groove a on the base. A hexagonal notch is opened at the center position of the open gear, and the center of the open gear coincides with the center of the opened hexagonal notch. The open gear is meshed and connected with at least one of the gear shaft d and the gear shaft e at any position; the nut sleeve is fixedly installed at the hexagonal notch of the open gear, and a groove b is provided on the outer edge of the nut sleeve, and the groove b fits with the hexagonal notch of the open gear. The model of the nut sleeve can be replaced according to usage requirements.

[0011] Furthermore, the observation device is installed on the front end surface of the upper shell, and can be a probe or other camera device. The observation device is electrically connected to the switching switch in the driving device. After the switching switch is turned on, the observation device starts working. The observation device is mainly used in situations where the threaded parts are difficult to observe with the naked eye.

[0012] The utility model adopts the above technical solution, and the utility model has the following beneficial effects: the utility model provides a hexagonal notch corresponding to the nut sleeve on the open gear, so that the threaded part can be inserted into the open gear through the nut sleeve for tightening or loosening, so that the electric wrench of the utility model can be conveniently used when some bolts are too long or when tightening nuts with pipes; the center of the nut sleeve coincides with the center of the hexagonal notch of the open gear, so the rotation of the nut sleeve is driven by the rotation of the open gear to tighten and loosen the threaded part, without rotating the housing of the electric wrench, so the operation is simple and convenient, and the operating range is reduced; on the other hand, the initial opening position of the open gear can be adjusted by the motor, so that the electric wrench It can match with threaded parts at any position without adjusting the position of the open gear by rotating the housing of the electric wrench to make the nut sleeve and the threaded part match; the open gear is driven to rotate by two gear shafts that are symmetrically distributed on the left and right. This symmetrically distributed structure can realize the continuous rotation of the open gear for 360 degrees, thereby realizing the rotation of the threaded part for one circle, improving the working efficiency of the electric wrench; the transmission device is symmetrically distributed, and during the rotation of the open gear, at least one gear shaft or meshes with the open gear, realizing the continuous rotation of the open gear. At the same time, this symmetrically distributed structure allows the motor to change the rotation angle during the forward and reverse rotation process except for the change in the rotation direction, thereby realizing the tightening and loosening of the threaded part. The nut sleeve can be replaced according to different usage requirements, which increases the scope of application of the electric wrench; the observation device arranged on the upper housing can be used in situations where it is difficult to observe the threaded part with the naked eye. The observation device enables the user to accurately find the position of the threaded part and perform operations; BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is an overall schematic diagram of the utility model.

[0014] Figure 2 It is an internal schematic diagram of the utility model.

[0015] Figure 3 It is a schematic diagram of the lower shell of the utility model.

[0016] Figure 4 It is an exploded view of the driving device of the utility model.

[0017] Figure 5 It is an exploded diagram of the reversing device of the utility model.

[0018] Figure 6 It is an exploded view of the transmission device of the utility model.

[0019] Figure 7 It is an exploded view of the working device of the utility model.

[0020] Figure 8 This is the control circuit diagram of the drive device and observation device of the utility model. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] In the description of the present utility model, it should be noted that the directions or positional relationships indicated by the terms "upper", "lower", "front", "back", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the utility model product is usually placed when in use. They are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present utility model.

[0024] like Figure 1-8As shown, an electric wrench is characterized in that it includes: a shell 1, a driving device 2, a reversing device 3, a transmission device 4, a working device 5 and an observation device 6; the reversing device 3 to the working device 5 are all installed inside the shell 1 and connected in sequence and can make a rotational motion in the shell 1; the shell 1 is divided into an upper shell 11 and a lower shell 12, the upper shell 11 is a hollow structure, the lower shell 12 includes a hand handle 121, a limit plate 122 and a base 123, the limit plate 122 is provided with a stepped cylindrical hole a1221, the base 123 is provided with five stepped cylindrical holes b1231 with the same structure from back to front, the upper shell 11 is provided with four stepped cylindrical holes with the same structure from back to front for installing a positioning support assembly, and a groove a1232 is also provided on the front end surface of the base 123 for accommodating the working device 5; the driving device 2 is arranged Installed on the hand handle 121 and the limit plate 122 of the lower shell 12, the driving device 2 serves as the overall power source and control, and can control the forward and reverse rotation of the working device 5, thereby realizing the tightening and loosening of the threaded parts; the upper and lower ends of the reversing device 3 are respectively engaged and connected with the driving device 2 and the transmission device 4, realizing the change of the power transmission plane; the transmission device 4 is symmetrically installed on both sides of the central axis of the lower shell 12, and the transmission device 4 is the power transmission of the working device 5, which not only plays a role in power transmission but also ensures the continuous rotation of the working device; the working device 5 is installed in the groove a1232 of the base 123 and can rotate in the groove a1232; the observation device 6 is fixedly installed on the front end face of the upper shell 11, and the observation device 6 can accurately find the position of the threaded parts and perform operations in occasions that are difficult to observe with the naked eye.

[0025] In an optional implementation of an embodiment of the utility model, in addition to the parts that are the same as the previous embodiment, the driving device 2 includes: a controller 21, a driving motor 22, a coupling 23, a bearing a24, a gear shaft a25, a flat key a26 and a flat key b27; the controller 21 and the driving motor 22 are fixedly mounted on the hand handle 121 of the lower shell 12; the gear shaft a25 is rotatably mounted on the limit plate 122, and the left end face of the gear shaft a25 is provided with a cylindrical boss; the bearing a24 is rotatably mounted in the stepped cylindrical hole a1221 of the limit plate 122, the left end of the bearing a24 is stuck in the step of the stepped cylindrical hole a1221, and the right end is slidably connected to the gear shaft a25; the left end of the coupling 23 is slidably connected to the driving motor 22 via the flat key a26, and the right end is slidably connected to the gear shaft a25 via the flat key b27. The controller 21 includes: a switching switch 211 and a main switch 212; the switching switch 211 is fixed on the right side of the hand-held handle 121, and the switching switch 211 is electrically connected to the drive motor 22 and the observation device 6; the main switch 212 is fixedly installed on the upper surface of the hand-held handle 121, and the main switch 212 is electrically connected to the drive motor 22. The main switch 212 has three gears. When it is set to the middle gear, the drive motor 22 does not rotate. When it is set to the front gear, the drive motor 22 rotates forward. When it is set to the rear gear, the drive motor 22 reverses.

[0026] When implementing: Figure 8 As shown, the switching switch 211 is electrically connected to the observation device 6 and the driving motor 22. When the switching switch 211 is pressed, the observation device 6 is powered on and starts working. In this embodiment, the observation device 6 can be externally connected to a display screen, and the observed image can be transmitted to the display screen. The main switch 212 is electrically connected to the driving motor 22. The main switch 212 is initially placed in the middle position. At this time, the driving motor 22 does not rotate. When the main switch 212 is placed in the right end position, the driving motor 22 starts to rotate forward, or when the main switch 212 is placed in the left end position, the driving motor 22 starts to reverse. The driving motor 22 drives the gear shaft a to start rotating, and the gear shaft a is meshed with the face gear shaft 31. The driving device 2 transmits power to the reversing device 3.

[0027] In an optional implementation of the embodiment of the utility model, in addition to the same parts as the previous embodiment, the reversing device 3 includes: a face gear shaft 31, a spur gear 32, a bearing b33, a flat key c34 and a sleeve 35; the bearing b33 is rotatably installed in the stepped cylindrical hole b1231 of the base 123, the lower end face of the bearing b33 is limited to the step of the stepped cylindrical hole b1231, and the inner ring of the upper end face of the bearing b33 is in contact with the sleeve 35; the lower shaft end of the face gear shaft 31 is rotatably installed on the base In the bearing b33 of 123, a keyway is provided on the shaft of the face gear shaft 31; the spur gear 32 is slidably connected to the face gear shaft 31 through the flat key c34, and a groove is provided in the inner hole of the spur gear 32; the flat key c34 is installed in the keyway of the face gear shaft 31, and the upper end surface of the flat key c34 fits with the groove in the inner hole of the spur gear 32; the sleeve 35 is installed between the bearing b33 and the spur gear 32, and is used to limit the axial movement of the spur gear 32; the face gear in the face gear shaft 31 is meshedly connected with the gear shaft a25 in the driving device 2.

[0028] During specific implementation: the reversing device 3 receives power from the driving device 2 through the face gear shaft 31. Since the face gear shaft 31 and the spur gear 32 are slidingly connected through the flat key c34, the synchronous rotation of the face gear shaft 31 and the spur gear 32 is achieved, and then the spur gear 32 transmits power to the transmission device 4.

[0029] In an optional implementation of an embodiment of the utility model, in addition to the same parts as the previous embodiment, the transmission device 4 includes: a gear shaft b41, a gear shaft c42, a gear shaft d43, a gear shaft e44 and four pairs of bearings for positioning support; the gear shaft b41 and the gear shaft c42 as well as the gear shaft d43 and the gear shaft e44 are symmetrically installed on the base 123 along the central axis of the lower shell 12, wherein the gear shaft b41 and the gear shaft c42 are meshed and connected with the spur gear 32 in the reversing device 3, and the gear shaft d43 and the gear shaft e44 are meshed and connected with the gear shaft b41 and the gear shaft c42 respectively, and the upper shaft ends and lower shaft ends of the above four gear shafts are provided with cylindrical bosses; the four pairs of bearings in the transmission device 4 are respectively installed in the stepped cylindrical holes of the upper shell 11 and the base 123, wherein the inner gear rings of one end faces of the four pairs of bearings are in contact with the cylindrical bosses of the four gear shafts, so that the four gear shafts only retain the degree of rotational freedom between the upper shell 11 and the lower shell 12.

[0030] During specific implementation: the gear shafts b41 and c42 in the transmission device 4 are respectively meshed and connected with the spur gear 32, and the gear shafts b41 and c42 transmit power to the gear shafts d43 and e44. Since the gear shafts d43 and e44 are symmetrically distributed along the central axis of the lower shell 12, this symmetrical structure enables the open gear 51 in the working device to rotate, and at least one of the gear shafts in the transmission device 4 is meshed with the open gear 51, thereby realizing continuous rotation of the open gear 51, and then realizing continuous tightening or loosening of the threaded part, thereby improving the working efficiency of the wrench.

[0031] In an optional implementation of an embodiment of the utility model, in addition to the parts that are the same as the previous embodiment, the working device 5 includes an open gear 51 and a nut sleeve 52; the open gear 51 is rotatably installed on the base 123, and the lower end surface of the open gear 51 is provided with a boss 511, and the boss 511 of the open gear 51 is matched with the groove a1232 on the base 123, and a hexagonal notch 512 is opened at the center position of the open gear 51, and the center of the open gear 51 coincides with the center of the opened hexagonal notch 512, and the open gear 51 is meshed and connected with at least one of the gear shaft d43 and the gear shaft e44 at any position; the nut sleeve 52 is fixedly installed at the hexagonal notch 512 of the open gear 51, and the outer edge of the nut sleeve 52 is provided with a groove b521, and the groove b521 is matched with the hexagonal notch 512 of the open gear 51. The model of the nut sleeve 52 can be replaced according to usage requirements, so that the applicability of the electric wrench is more extensive.

[0032] During specific implementation: since the gear shaft d43 and the gear shaft e44 are meshed and connected with the open gear 51, power is transmitted from the transmission device 4 to the working device 5, the open gear 51 and the nut sleeve 52 are detachably connected, and the rotation of the open gear 52 drives the rotation of the nut sleeve 52, thereby realizing the tightening and loosening operations of the threaded member stuck in the nut sleeve 52, and the hexagonal notch 512 on the open gear 51 can put the threaded member into the open gear 51 through the nut sleeve 52 for tightening or loosening, so that the electric wrench of the utility model can be conveniently used in some cases where the bolts are too long, or in cases where nuts with pipes are tightened; on the other hand, the center of the nut sleeve 52 coincides with the center of the hexagonal notch 512 of the open gear 51, so the rotation of the nut sleeve 51 is driven by the rotation of the open gear 51 to realize the tightening and loosening of the threaded member, without rotating the housing 1 of the electric wrench, so that the electric wrench can work in a narrow space.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the utility model, and they should all be included in the scope of the claims and specification of the utility model.

Claims

1. An electric wrench, characterized in that: include: A housing (1), a driving device (2), a reversing device (3), a transmission device (4), a working device (5) and an observation device (6); the reversing device (3) to the working device (5) are all installed inside the housing (1) and connected in sequence and can perform rotational movement in the housing (1); the housing (1) is divided into an upper housing (11) and a lower housing (12); the upper housing (11) is a hollow structure; the lower housing (12) comprises a hand-held handle (121), a limit plate (122) and a base (123); the limit plate (122) is provided with a stepped cylindrical hole a (1221); the base (123) is provided with five stepped cylindrical holes b (1231) with the same structure from back to front; the upper housing (11) is provided with four stepped cylindrical holes with the same structure from back to front for installing a positioning support component; the front end surface of the base (123) is also provided with a groove a (1232) for accommodating the working device (5); The driving device (2) is mounted on the hand handle (121) and the limit plate (122) of the lower shell (12). The driving device (2) serves as the overall power source and control and can control the forward and reverse rotation of the working device (5). The upper end and the lower end of the reversing device (3) are respectively meshed and connected with the driving device (2) and the transmission device (4), thereby realizing the change of the power transmission plane. The transmission device (4) is symmetrically mounted on both sides of the central axis of the lower shell (12). The transmission device (4) is the power transmission of the working device (5), which not only plays a role in power transmission but also ensures the continuous rotation of the working device. The working device (5) is mounted in the groove a (1232) of the base (123) and can rotate in the groove a (1232). The observation device (6) is fixedly mounted on the front end surface of the upper shell (11). The observation device (6) can accurately find the position of the threaded part and perform operations in situations where it is difficult to observe with the naked eye.

2. An electric wrench according to claim 1, characterized in that: The driving device (2) comprises: a controller (21), a driving motor (22), a coupling (23), a bearing a (24), a gear shaft a (25), a flat key a (26) and a flat key b (27); the controller (21) and the driving motor (22) are fixedly mounted on a hand handle (121) of the lower housing (12); the gear shaft a (25) is rotatably mounted on a limit plate (122), and a cylindrical boss is provided on the left end surface of the gear shaft a (25); the bearing a (24) is rotatably mounted in a stepped cylindrical hole a (1221) of the limit plate (122), the left end of the bearing a (24) is clamped at the step of the stepped cylindrical hole a (1221), and the right end is slidably connected to the gear shaft a (25); the left end of the coupling (23) is slidably connected to the driving motor (22) via the flat key a (26), and the right end is slidably connected to the gear shaft a (25) via the flat key b (27).

3. An electric wrench according to claim 2, characterized in that: The controller (21) comprises: a switching switch (211) and a main switch (212); the switching switch (211) is fixed on the right side of the hand-held handle (121), and the switching switch (211) is electrically connected to the drive motor (22) and the observation device (6); the main switch (212) is fixedly mounted on the upper surface of the hand-held handle (121), and the main switch (212) is electrically connected to the drive motor (22).

4. The electric wrench according to claim 1, characterized in that: The reversing device (3) comprises: a face gear shaft (31), a spur gear (32), a bearing b (33), a flat key c (34) and a sleeve (35); the bearing b (33) is rotatably mounted in a stepped cylindrical hole b (1231) of a base (123); the lower end surface of the bearing b (33) is restricted at the step of the stepped cylindrical hole b (1231); the inner ring of the upper end surface of the bearing b (33) contacts the sleeve (35); the lower shaft end of the face gear shaft (31) is rotatably mounted in the bearing b (33) of the base (123); the face gear shaft (31) is rotatably mounted in the bearing b (33) of the base (123); 1) is provided with a keyway; the spur gear (32) is slidably connected to the face gear shaft (31) via a flat key c (34), and a groove is provided in the inner hole of the spur gear (32); the flat key c (34) is installed in the keyway of the face gear shaft (31), and the upper end surface of the flat key c (34) fits in the groove of the inner hole of the spur gear (32); the sleeve (35) is installed between the bearing b (33) and the spur gear (32) to limit the axial movement of the spur gear (32); the face gear in the face gear shaft (31) is meshedly connected with the gear shaft a (25) in the driving device (2).

5. The electric wrench according to claim 1, characterized in that: The transmission device (4) comprises: a gear shaft b (41), a gear shaft c (42), a gear shaft d (43), a gear shaft e (44) and four pairs of bearings for positioning support; the gear shaft b (41) and the gear shaft c (42) as well as the gear shaft d (43) and the gear shaft e (44) are symmetrically mounted on the base (123) along the central axis of the lower housing (12), wherein the gear shaft b (41) and the gear shaft c (42) are both meshedly connected with the spur gear (32) in the reversing device (3), and the gear shafts are arranged on the base (123). The shaft d (43) and the gear shaft e (44) are meshedly connected with the gear shaft b (41) and the gear shaft c (42), respectively, and the upper shaft ends and lower shaft ends of the above four gear shafts are provided with cylindrical bosses; the four pairs of bearings in the transmission device (4) are respectively installed in the stepped cylindrical holes of the upper shell (11) and the base (123), wherein the inner gear rings of one end surface of the four pairs of bearings are in contact with the cylindrical bosses of the four gear shafts, so that the four gear shafts only retain the degree of rotational freedom between the upper shell (11) and the lower shell (12).

6. The electric wrench according to claim 5, characterized in that: The four pairs of bearings are respectively installed in the stepped cylindrical holes of the upper shell (11) and the base (123). Since the structures and installation methods of the four pairs of bearings are the same, the bearings c (45) and bearings d (46) used for positioning and supporting the gear shaft b (41) are used as examples for explanation. The outer gear ring of the upper end surface of the bearing c (45) is clamped in the step of the stepped cylindrical hole of the upper shell, the inner gear ring of the lower end surface of the bearing c (45) contacts the cylindrical boss of the upper shaft end of the gear shaft b, and the outer gear ring of the lower end surface of the bearing d (46) is clamped in the step of the stepped cylindrical hole of the base (123), and the inner gear ring of the upper end surface of the bearing d (46) contacts the cylindrical boss of the lower shaft end of the gear shaft b.

7. The electric wrench according to claim 1, characterized in that: The working device (5) comprises an open gear (51) and a nut sleeve (52); the open gear (51) is rotatably mounted on a base (123); a boss (511) is provided on the lower end surface of the open gear (51); the boss (511) of the open gear (51) is matched with a groove a (1232) on the base (123); a hexagonal notch (512) is provided at the center of the open gear (51); the center of the open gear (51) coincides with the center of the opened hexagonal notch (512); the open gear (51) is meshedly connected with at least one of the gear shaft d (43) and the gear shaft e (44) at any position; the nut sleeve (52) is fixedly mounted at the hexagonal notch (512) of the open gear (51); a groove b (521) is provided on the outer edge of the nut sleeve (52); the groove b (521) is matched with the hexagonal notch (512) of the open gear (51); and the model of the nut sleeve (52) can be replaced according to usage requirements.

8. The electric wrench according to claim 1, characterized in that: The observation device (6) is mounted on the front end surface of the upper shell (11), and the observation device (6) is electrically connected to the controller (21) in the drive device (2).

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