CN200991885Y

CN200991885Y - Electric tool

Info

Publication number: CN200991885Y
Application number: CN 200620170754
Authority: CN
Inventors: 陈成忠; 张士松
Original assignee: Positec Power Tools Suzhou Co Ltd
Current assignee: Positec Power Tools Suzhou Co Ltd
Priority date: 2006-12-19
Filing date: 2006-12-19
Publication date: 2007-12-19
Anticipated expiration: 2016-12-19

Abstract

The utility model relates to an electric tool, comprising a motor, a motor crust housing the motor, a gear case connected with the motor crust and a work head assembly. Two openings whose axes angle, are arranged on the gear case, and the transmission assemblies driven by the motor are arranged in the openings. The work head assembly can be inserted into one of the openings and meshes with the transmission assembly in the gear case; the gear case can rotate with an angle of 360 degrees. Compared with prior art, the utility model provides an electric tool with a work head that can be conveniently transferred under different working conditions, and provides an electric tool with a work head that can work within various angles, particularly in a narrow area. The utility model has a compact structure, small size and low processing cost.

Description

Electric tool

Technical Field

The utility model relates to an electric tool with a working head capable of working under a plurality of angles, in particular to an electric tool capable of working in narrow areas.

Background

The use of electric tools is very common at present, but each time the electric tool is used, more than several electric tools are needed to complete different works, such as: when the cabinet is assembled, a gun drill is used for drilling holes, then a screw driver is used for screwing the screws, and particularly when a space for holding a gun drill handle is unavailable in narrow places, an angle drill is used for drilling holes. Japanese patent application JP11320224 discloses a structure of an angle drill, which is distinguished from a conventional gun drill in that the drill chuck axis is perpendicular to the motor axis, thus enabling operation in a narrow area. In order to solve the problems of too many tools to be carried during work and too much time wasted in replacing the tools, a multifunctional electric tool is needed, the working head of which can work under a plurality of angles, especially in a narrow area.

US patent 5533581 discloses a structure for interconversion between a gun drill and an angle drill, which is characterized in that a ball is arranged between a gear box and a body of a head part, so that relative rotation can be generated between the gear box and the body of the gun drill, and the rotation axis of the gear box of the gun drill is arranged at 45 degrees with respect to the body, so that the original gun drill is converted into the angle drill after the gear box of the gun drill rotates 90 degrees, and the mechanism in the gear box is mainly realized by a primary bevel gear, which has the following defects: because the parts are not coaxial, the requirement on machining precision is high, and the machining is difficult; and because the reduction bevel gear of gear box inside places for the slash, so electric tool size can be great, and the processing cost is high, is difficult for putting into batch production. Although the drill of this patent also employs a gear box, since it has only a single opening and a single shaft, the gear box must be rotated when the power tool is required to change states, which results in a complicated structure for connecting the gear box to the power tool and inconvenient operation.

US patent application US2006147283 also discloses a gun drill with a rotatable head, but the axis of the working head of the gun drill is always coaxial with the axis of the motor, so that the function of an angle drill cannot be realized, and the gun drill cannot work in a narrow area. And the other working head arranged on the body of the electric tool does not have any connection with the motor when the electric tool works, namely the working head and the motor do not have any transmission component, so the working head is equivalent to an accessory of the electric tool.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide an electric tool which can work under a plurality of angles, in particular to work in a narrow area; another object of the present invention is to provide an electric tool with simple and convenient processing, compact structure and small overall size.

The utility model provides a technical scheme that prior art problem adopted is: a power tool, comprising: the working head assembly is selectively inserted into one of the openings and meshed with the transmission assembly in the gear box.

A locking assembly is arranged between the motor shell and the gear box of the electric tool, and the locking assembly enables the gear box to be rotatably connected with the motor shell relative to the axis of the motor. Wherein, the locking component is fixed with the motor shell through a screw; the locking assembly comprises a locking sleeve, a concave hole is formed in the front end of the locking sleeve, a ball and a spring are placed in the concave hole, one end of the spring abuts against the inner wall of the locking sleeve, and the other end of the spring abuts against the ball; the rear end face of the shell of the gear box is provided with semicircular holes in a row in the circumferential direction, and balls can be partially accommodated, so that the locking assembly and the gear box can rotate relatively.

The central axis of the first opening on the gear box is parallel to the motor axis of the motor, and the central axis of the second opening on the gear box is perpendicular to the motor axis of the motor. The transmission assembly in the gear box comprises a rear shaft driven by a motor and a gear assembly connected with the rear shaft, wherein the gear assembly comprises a first bevel gear and a second bevel gear which are meshed with each other, the central axis of the first bevel gear is coincident with that of the first opening, and the central axis of the second bevel gear is coincident with that of the second opening.

In a preferred embodiment, the working head assembly comprises a front shaft and a working head connected with the front shaft.

After the front shaft is inserted into any one of the openings, the front shaft and the rear shaft are engaged through a transmission assembly in the gear box. Furthermore, when the front shaft is inserted into the first opening, the front shaft and the rear shaft are in matched transmission between an external spline of the front shaft and an internal spline of the rear shaft; the front shaft is inserted into the second opening and is in matching engagement with the second bevel gear.

In another embodiment, the gear assembly includes a third bevel gear and first and second bevel gears respectively engaged with the third bevel gear.

Or, in the above electric tool, the gear box is internally provided with a limit sleeve, an inner hole of the limit sleeve is provided with an inner spline, the outer side of the limit sleeve is also provided with a notch, and the notch is also sleeved with a clamp spring; the front shaft can be fixedly connected by a limiting sleeve.

Further, in another embodiment, the workhead assembly may be a single workhead, and the transmission assembly includes a rear shaft driven by a motor, a gear assembly connected to the rear shaft, and workhead clamping members.

The working head clamping piece is arranged in the first opening and fixedly connected with the rear shaft, and the working head can be inserted into the working head clamping piece and is matched and connected with the working head clamping piece. The other working head clamping piece is positioned in the second opening and is matched and connected with the second bevel gear, the rear shaft is matched and connected with the first bevel gear, and the working head can be inserted into any one of the working head clamping pieces and is matched and connected with the same.

Furthermore, in the electric tool, the front shaft and the working head can be fixedly connected through threads, and the front shaft is provided with a clamping part for screwing the threads; the working head can be a drill chuck for clamping a drill bit, and can also be a screwdriver head, a grinding wheel sheet, a grinding wheel rod, a saw blade and the like. A sealing ring is further fixed in the gear box and used for preventing lubricating oil from leaking.

Compared with the prior art, the beneficial effects of the utility model are that: the utility model provides an electric tool of working head convenient conversion between different operating condition to a working head can work under a plurality of angles, especially can be at the electric tool of narrow regional work, moreover the utility model discloses a compact structure, whole size is little, and the processing cost is low.

Drawings

The technical solution of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is a perspective view of a first state of a first embodiment of the present invention.

Fig. 2 is a partial cross-sectional view of a first state of a first embodiment of the present invention.

Fig. 2a, 2b, 2c are enlarged views of a portion of fig. 2.

Fig. 3 is a perspective view of a second state of the first embodiment of the present invention.

Fig. 4 is a partial cross-sectional view of the first embodiment of the present invention in a second state.

Fig. 5 is a partial exploded view of the first embodiment of the present invention.

Fig. 6 is an exploded view of the gearbox of the first embodiment of the present invention.

Fig. 7 is a schematic diagram of a second embodiment of the present invention.

Fig. 8 is a schematic view of a third embodiment of the present invention.

Fig. 9 is a schematic view of a fourth embodiment of the present invention.

Fig. 10a, 10b, 10c, 10d are schematic views of various embodiments of workhead assemblies of the present invention.

Wherein,

1 motor housing 10 electric tool 2 motor

20 motor axis 21 motor shaft 22 motor fan

24 spring 3 rear axle 31 internal spline

32 notch 33 external spline 34 concave ring

35 thin shaft part 4 work head assembly 41 work head

42 front axle 421 screw 422 clamping part

423 intermediate shaft part 424 external spline 425 groove

5-stroke gear 6 gearbox 60 shell

61 first opening 611 central axis 62 second opening

621 center axis 63 screw hole 64 screw

65 semicircular hole 7 locking component 70 locking sleeve

71 concave hole 72 ball 73 spring

74 tightening screw 81 first bevel gear 811 central axis

813 internal spline 82 second bevel gear 821 central axis

823 internal spline 825 central axis 827 notch

83 circlip 831 concave 84 sealing ring

85-collar 86 retainer ring 87 bearing

88 third bevel gear 89 as a head clamping part 9 limiting sleeve

91 internal spline 92 notch 101 upper cover

102 case cover

Detailed Description

The utility model relates to an electric tool with a working head capable of working under a plurality of angles. Fig. 1 to 6 disclose a first embodiment of the present invention.

As shown in fig. 1 and 2, the electric power tool 10 includes a motor housing 1 and a head assembly 4, a motor 2 housed in the motor housing 1 has a motor axis 20, the motor 2 drives a motor shaft 21, and a motor fan 22 for cooling is fixed to the motor shaft 21, in accordance with the prior art. The front end of the motor shaft 21 is in a gear shape and is meshed with the impact gear 5, and the two are in matched transmission. Impact gear 5 is fixed to rear axle 3 for rotation with rear axle 3, and impact gear 5 is fixed to a thin shaft portion 35 (shown in fig. 5) of rear axle 3 and abuts impact gear 5 to provide a step portion of rear axle 3, thus ensuring that impact gear 5 and rear axle 3 move axially together. In addition, the working head assembly 4 is also composed of a working head 41 and a front shaft 42 which are fixed as in the prior art. The working head 41 in the preferred embodiment is a drill chuck.

As shown in fig. 1 to 4, the power tool 10 further includes a gear box 6 connected to the motor housing 1, and a locking assembly 7 for connection. The workhead assembly 4 can be selectively partially inserted into the gear housing 6.

As shown in fig. 5, the gear case 6 is provided with a first opening 61 and a second opening 62, whose

central axes

611, 621 are perpendicular to each other. Wherein the front shaft 42 fixed to the working head 41 can be inserted into either one of the

openings

61, 62. The central axis 611 of the first opening 61 of the gear box 6 is parallel to the motor axis 20 (shown in fig. 2), and the electric tool is in the first state when the front shaft 42 is inserted into the first opening 61; the central axis 621 of the second opening 62 of the gear box 6 is perpendicular to the motor axis 20 (shown in fig. 2), and the electric power tool is in the second state when the front shaft 42 is inserted into the second opening 62.

The specific structure of the front axle 42 and the rear axle 3 is also disclosed in fig. 5. The front end of the front shaft 42 is provided with a screw 421 and a clamping part 422, and the front shaft 42 is fastened with the working head 41 through the screw 421 in accordance with the prior art. The clamping portion 422 is two symmetrical planes disposed on the circular shaft, and is used for matching with the clamping surface of the wrench to tighten the screw 421. The front axle 42 also includes an intermediate shaft portion 423 with external splines 424 and a groove 425 at the rear of the intermediate shaft portion 423. The rear axle 3 is provided with internal splines 31 at its forward end for co-operating transmission with external splines 424 of the front axle 42. The rear axle 3 is provided with an external spline 33 on a part of the outer circumference thereof, a notch 32 at the front end of the external spline 33, a recessed ring 34 at the rear end, and a thin shaft part 35 at the rear end of the rear axle 3 for fixing the impact gear 5.

As shown in fig. 2 and 2b, in the first state, that is, when the front shaft 42 is inserted into the first opening 61, the external splines 424 of the front shaft 42 are inserted into the internal splines 31 of the rear shaft 3, the splines are in fit transmission to enable the front shaft 42 and the rear shaft 3 to rotate together, and the rotating state is transmitted to the working head 41, that is, a drill chuck, so that the ordinary gun drill function is achieved.

A specific structure of the gear box 6 is disclosed in fig. 6. The gear housing 6 comprises two housings 60, which are provided with four screw holes 63, and screws 64 are passed through the screw holes 63 to assemble the two housings 60 together. The first opening 61 and the second opening 62 are formed by two housings 60 of the gearbox after they have been assembled together.

A first bevel gear 81 and a second bevel gear 82 are arranged in the gear housing 6 in engagement with each other, wherein a central axis 811 of the first bevel gear 81 coincides with a central axis 611 of the first opening 61 and a central axis 821 of the second bevel gear 82 coincides with a central axis 621 of the second opening 62. An inner spline 813 is arranged in an inner hole of the first bevel gear 81 and is always sleeved on the periphery of the rear shaft 3 to be matched with the outer spline 33 of the rear shaft 3 for transmission. The second bevel gear 82 is provided with a central shaft 825, and an inner hole thereof is provided with an inner spline 823 which is the same as the inner spline 31 of the rear shaft 3 and can also be used for inserting and matching the outer spline 424 of the front shaft 42 for transmission.

As shown in FIGS. 3 and 4, when the front shaft 42 is inserted into the second opening 62, the external splines 424 of the front shaft 42 are inserted into the internal splines 823 of the second bevel gear 82. The transmission of the front axle 42 and the rear axle 3 includes that the rotation of the rear axle 3 drives the first bevel gear 81 to rotate through the external splines 33 and the internal splines 813 of the first bevel gear 81, and the second bevel gear 82 engaged with the first bevel gear 81 drives the front axle 42 to rotate through the cooperation of the internal splines 823 and the external splines 424 of the front axle 42. The rotation state is transmitted to the drill chuck 41, and the central axis of the working head component 4 is vertical to the motor axis 20 at the moment, so that the common angle drill function is achieved, and the drill can be used for drilling in a narrow area.

The following preferred embodiments are now adopted in order to prevent the front axle 42 from coming off the rear axle 3 during operation. As shown in fig. 6, a snap spring 83 is further included in the gear housing 6, the snap spring 83 is a wavy and elastic metal wire, and there are three recesses 831 at the valley positions. As shown in fig. 2 and its enlarged partial view 2b, the notch 32 of the rear axle 3 is sleeved with a snap spring 83, and the concave portion 831 of the snap spring 83 can pass through the notch 32, i.e. the distance between the vertexes of the concave portion 831 is smaller than the inner diameter of the rear axle 3. When the front axle 42 is inserted into the first opening 61, the recess 831 is received in the recess 425 of the front axle 42, so that the axial displacement between the front axle 42 and the rear axle 3 is relatively fixed.

Similarly, as shown in fig. 4, the second bevel gear 82 has a notch 827 at the tail of the central shaft 825, and a snap spring 83 is also sleeved in the notch 827, when the front shaft 42 is inserted into the second opening 62, a recess 831 of the snap spring 83 can pass through the notch 827 and be accommodated in the groove 425 of the front shaft 42, and the axial displacement between the front shaft 42 and the second bevel gear 82 can be relatively fixed by the action of the snap spring 83. Of course, the method for fixing the front axle is not limited, and a simple buckle structure is within the protection scope of the present invention.

As shown in fig. 5, the locking assembly 7 is a circular ring type metal sleeve, and the locking assembly 7 is fixed to the motor housing 1 by a fastening screw 74. The locking assembly 7 comprises a locking sleeve 70, three concave holes 71 are formed in the front end of the locking sleeve 70, balls 72 are placed in the concave holes 71, a partial cross-sectional view of the locking sleeve 70 is shown in fig. 2a, springs 73 are further placed in the concave holes 71, one ends of the springs 73 abut against the inner wall of the locking sleeve 70, the other ends of the springs 73 abut against the balls 72, and when the locking assembly is in an initial state, the springs 73 are in a compressed state and always tend to push the balls 72 outwards.

As shown in fig. 6, a plurality of semicircular holes 65 are arranged in a circumferential direction on the rear end surface of the housing 60 of the gear case 6 and can partially receive the balls 72. When one part of the ball 72 is received in the semicircular hole 65 and the other part is received in the concave hole 71, the gear case 6 and the locking assembly 7 are fixed together. Since the rear shaft 3 and the gear box 6 are rotatable relative to each other, the gear box 6 can be rotated after the front shaft 42 is inserted into the second opening 62, so that the workhead assembly 4 can rotate 360 degrees on a plane perpendicular to the motor axis 20. When the gearbox 6 is rotated, the balls 72 will be released from the semi-circular holes 65, and the rear surface of the gearbox 6 will act as a compression on the balls 72, causing the springs to contract. When the gear box 6 rotates to a required angle, the ball 72 will be sprung into the semicircular hole 65 by the spring 73, and partially received in the semicircular hole 65 and partially received in the concave hole 71 of the locking sleeve 70, so that the gear box 6 and the locking assembly 7 are fixed together. Therefore, the locking assembly 7 is provided to enable the working head assembly 4 of the power tool 10 to rotate with the gear box 6 in the second state, i.e., the angle drill state of the present embodiment, so that the drill bit of the angle drill can work after being fixed at any angle within 360 degrees.

Further, as shown in fig. 2 and 6, two seal rings 84 are further included in the gear housing 6, and are respectively fitted on the outer peripheries of the rear shaft 3 and the second bevel gear 82, for maintaining the lubricating oil placed on the bevel gears 81, 82. As shown in fig. 6 and fig. 2 and 2c, a collar 85 is accommodated in the recessed ring 34 of the rear axle 3, and a retainer ring 86 abuts on one side of the collar 85. A spring 24 is provided with one end abutting against the collar 86 and the other end abutting against the impact gear 5. Like the prior art, under the action of the spring 24, the impact gear 5 can drive the rear shaft 3 to generate impact with a certain frequency, so as to drive the working head assembly 4 to generate impact with a certain frequency in the rotating process.

A second embodiment of the invention is disclosed in fig. 7. Different from the first embodiment, a third bevel gear 88 is further provided in the gear case 6, and can be engaged with both the first bevel gear 81 and the second bevel gear 82. Thus, first bevel gear 81 and second bevel gear 82 can rotate in the same direction at the same time due to the transitional effect of third bevel gear 88. For example, when the first bevel gear 81 rotates clockwise, the second bevel gear 82 also rotates clockwise. In fig. 7, the present invention is in the first state, and when the working head 41 and the front shaft 42 are pulled out and inserted along the dotted line, the present invention can be changed into the second state. The rotational directions of the working head 41 and the front shaft 42 at this time are identical to the rotational directions of the working head 41 and the front shaft 42 in the first state.

In order to achieve the consistency of the rotation direction of the working head 41 in the two states, the present invention further discloses a third embodiment. As shown in fig. 8, a stop collar 9 is further provided in the gear case 6, and an internal spline 91 having a shape conforming to the internal spline 823 of the second bevel gear 82 is provided in the inner hole thereof; a notch 92 is further provided on the outer side of the other end of the stop collar 9, and a snap spring 83 (shown in fig. 2 and 2 b) is also provided inside the notch 32 of the rear axle 3, which has the same shape and function as the snap spring 83 provided on the front axle 3, and can play a role of fixing the axial displacement of the front axle 42 when the front axle 42 is inserted. The second bevel gear 82 in this embodiment is suitably modified in shape to include a recess in the outer side of the central shaft 825 and a bearing 87 disposed therein. An upper cover 101 and a cover 102 are also screwed to the housing 60 of the gear case 6, and both functions to fix the bearing 87 and also serve as a part of an aesthetic appearance. Like the second embodiment in fig. 7, the utility model of fig. 8 is also in the first state, when the working head 41 and the front axle 42 are pulled out and inserted along the dotted line, the utility model can be converted into the second state, and the rotation direction of the working head 41 is the same as that of the working head 41 in the first state. The principle is as follows: although the bevel gears 81 and 82 are rotated in opposite directions, the insertion direction of the working head 41 and the front shaft 42 in the second state is opposite to that of the first embodiment, so that the rotation directions of the working head 41 in the two states are identical. In this embodiment, the working chuck 41 is a drill chuck, and in actual operation, clockwise rotation of the drill in the first state may be used for hole rotation; when the drill bit is converted into the second state, the drill bit also rotates clockwise and is also used for rotating holes, so that the electric tool has the function of a common angle drill.

A fourth embodiment of the invention is disclosed in fig. 9. The gearbox 6, which is connected to the motor housing 1 by the locking assembly 7, likewise comprises a first opening 61 and a second opening 62, the housing interior of which comprises a rear axle 3 driven by the motor 2. A workhead clamping member 89 is disposed in the first opening 61, and in the preferred embodiment, the workhead clamping member 89 is a screw sleeve and is integrally formed with the rear axle 3. The front end of the screwdriver sleeve is slightly exposed out of the shell of the gear box. In this embodiment, the tail of the screwdriver head of the working head 41 is a regular hexagon; and the front end of the screwdriver sleeve is provided with an inner hexagon, so that the screwdriver sleeve and the screwdriver sleeve can be connected in a plug-in matching manner. When the screwdriver bit 41 is inserted into the screwdriver sleeve, the first state of the power tool is formed, i.e. becomes a normal screwdriver.

In this embodiment, a first bevel gear 81 and a second bevel gear 82 are also provided in the gear housing 6, which are meshed with each other, and as in the previous three embodiments, a central axis 811 of the first bevel gear 81 coincides with a central axis 611 of the first opening 61, and a central axis 821 of the second bevel gear 82 coincides with a central axis 621 of the second opening 62. Wherein, the rear shaft 3 is connected with the first bevel gear 81 by a spline; at the same time, a workholding member 89 is positioned within the second opening 62 and inserted into the second bevel gear 82, again with the spline 823 mating. The workhead clamping member 89, which is located in the first opening 61, is also a screwdriver sleeve, the front end of which is also provided with a hexagon socket and is slightly exposed outside the housing of the gearbox, and the power tool is in the second state when the screwdriver head 41 is inserted along the dashed line in the figure, i.e. into the workhead clamping member 89 in the second opening 62. The motor 2 drives the rear shaft 3 to rotate, so as to drive the two bevel gears to rotate, so that the screwdriver sleeve drives the screwdriver head 41 to rotate together, and the screwdriver head 41 starts to work. The electric tool can be used for screwing in a narrow area.

In this embodiment, both work head clamps 89 extend slightly outside the gear box 6 for ease of assembly and disassembly of the work head 41; alternatively, the workholding fixture 89 may be provided entirely inside the gear housing 6 for other reasons such as aesthetics.

In the first to third embodiments, i.e., the working head 41 shown in fig. 1 to 8 is a drill chuck, which is specially used for clamping a drill bit to achieve the function of a gun drill or an angle drill; the working head 41 in the fourth embodiment is a screwdriver head; similarly, the working head 41 may also take other forms, such as a grinding head in fig. 10a, a grinding wheel bar in fig. 10c, etc., fixed in cooperation with the threads 421 of the front axle 42; alternatively, the working head 41 may be a grinding wheel as shown in fig. 10b, a saw blade as shown in fig. 10d, or the like, and fixed to the front axle 42 by means of bolts, screws, or the like. Of course, it is not limited to the above-mentioned functions. Thus, the same electric tool can have different functions only by replacing the working head, and a series of actions such as drilling, sawing, grinding and the like can be realized in a narrow area.

In addition to the preferred embodiments described above, there are numerous specific embodiments of the present invention. Such as: the structure is complicated by adopting multi-stage gear transmission in the motor shell 1 or the gear box 6; or the locking mechanism of the gear box adopts threads or pin through holes and the like, so that the gear box can also achieve the rotating function, and the structure is complex and is not described much; or a protective cover is arranged on all the openings of the gear box which are not used in the work, so that the gear box is protected and the appearance is attractive. All technical solutions formed by adopting equivalent substitutions or equivalent transformations fall within the scope of the present invention.

Claims

1. A power tool (10) comprising: motor (2), accommodate motor casing (1) of motor, gear box (6) that are connected with motor casing (1) to and working head subassembly (4), its characterized in that: the gear box (6) is provided with a first opening (61) and a second opening (62) with mutually angled axes, a transmission assembly driven by the motor (2) is arranged in the openings, and the working head assembly (4) is selectively inserted into one of the openings and is meshed with the transmission assembly in the gear box (6).

2. The power tool of claim 1, wherein: a locking assembly (7) is arranged between the motor shell (1) and the gear box (6), and the gear box (6) is rotatably connected with the motor shell (1) relative to the motor axis (20) through the locking assembly (7).

3. The power tool of claim 2, wherein: locking Assembly (7) are including lock sleeve (70), the front end of lock sleeve (70) is equipped with shrinkage pool (71), place ball (72) and spring (73) in shrinkage pool (71), spring (73) one end is supported and is leaned on the inner wall of lock sleeve (70), the other end supports and leans on ball (72), the rear end face of shell (60) of gear box (6) is arranged in the circumferencial direction and is provided with semicircle orifice (65), ball (72) in shrinkage pool (71) can all be partially acceptd in every semicircle orifice (65).

4. The electric power tool according to any one of claims 1 to 3, characterized in that: the transmission assembly comprises a rear shaft (3) driven by the motor (2) and a gear assembly connected with the rear shaft, and the working head assembly (4) comprises a front shaft (42) and a working head (41) connected with the front shaft.

5. The power tool of claim 4, wherein: the central axis (611) of the first opening (61) on the gearbox (6) is parallel to the motor axis (20) of the motor (2).

6. The power tool of claim 5, wherein: the front shaft (42) is provided with an external spline (424), the rear shaft (3) is provided with an internal spline (31), the front shaft (42) is inserted into the first opening (61), and the external spline (424) of the front shaft (42) is in matched transmission with the internal spline (31) of the rear shaft (3).

7. The power tool of claim 4, wherein: the central axis (621) of the second opening (62) on the gear box (6) is perpendicular to the motor axis (20) of the motor (2).

8. The power tool of claim 7, wherein: the gear assembly comprises a first bevel gear (81) and a second bevel gear (82) which are meshed with each other, wherein the central axis (811) of the first bevel gear (81) is coincident with the central axis (611) of the first opening (61), and the central axis (821) of the second bevel gear (82) is coincident with the central axis (621) of the second opening (62).

9. The power tool of claim 8, wherein: the front shaft (42) is inserted into the second opening (62), and the front shaft (42) is in matching engagement with the second bevel gear (82).

10. The power tool of claim 7, wherein: the gear assembly comprises a third bevel gear (88) and a first bevel gear (81) and a second bevel gear (82) which are respectively meshed with the third bevel gear (88).

11. The power tool of claim 4, wherein: the front shaft (42) and the working head (41) are fixedly connected through threads (421), and the front shaft (42) is also provided with a clamping part (422) for screwing the threads.

12. The electric power tool according to any one of claims 1 to 3, characterized in that: the working head assembly (4) is a single working head (41), and the transmission assembly comprises a rear shaft (3) driven by the motor (2), a gear assembly connected with the rear shaft and a working head clamping piece (89).

13. The power tool of claim 12, wherein: the central axis (611) of the first opening (61) on the gear box (6) is parallel to the motor axis (20) of the motor (2), the central axis (621) of the second opening (62) is perpendicular to the motor axis (20) of the motor (2), the working head clamping piece (89) is arranged in the first opening (61) and fixedly connected with the rear shaft (3), and the working head (41) can be inserted into the working head clamping piece (89) and is matched and connected with the working head clamping piece.

14. The power tool of claim 13, wherein: the gear assembly comprises a first bevel gear (81) and a second bevel gear (82) which are meshed with each other, a working head clamping piece (89) is arranged in the second opening (62) and is connected with the second bevel gear (82) in a matching mode, the rear shaft (3) is connected with the first bevel gear (81) in a matching mode, and the working head (41) can be inserted into the working head clamping piece (89) and is connected with the working head clamping piece in a matching mode.