CN213197317U - Hand-held power tool - Google Patents

Abstract

The utility model relates to a hand-held power tool, which comprises a casing; a motor; an output shaft for coupling to a working member; a transmission mechanism; a case housing at least a part of the transmission mechanism; the box body is provided with an end cover, the end cover is positioned between the motor and the transmission mechanism along the axial direction of the motor shaft, and an accommodating part for accommodating and supporting the bearing is arranged on the end cover; the planetary gear train comprises a primary planet gear and a first speed change gear which is fixedly arranged relative to the box body, the first speed change gear comprises a main body part and a side wall part which is positioned on one side of the main body part, an inner gear ring which is meshed with the primary planet gear is arranged on the inner side of the main body part, the side wall part radially extends between the end cover and the planet gear, and the bearing is axially abutted to the side wall part. The side wall part plays a role of axial limiting the motor and also plays a role of spacer isolation; simple and compact structure and convenient installation.

Description

Hand-held power tool

Technical Field

The present application relates to the field of power tools, and more particularly, to a hand-held power tool.

Background

In the prior art, a first-stage internal gear of a reduction gearbox of an electric drill or a screwdriver type handheld power tool only has a transmission function, so that a gasket is required to be additionally arranged at the end part of a first planet gear, and the first planet gear is prevented from rubbing a shell. In addition, the bearing of supporting the motor shaft needs extra axial positioning structure that sets up, and these structures can increase the length of gear box, lead to the complete machine to lengthen, are unfavorable for packing and transportation, and it is also inconvenient to operate in narrow and small space.

Referring to fig. 1a, a schematic view of a portion of a prior art hand held power drill 10a includes a housing 100a, a motor 20a and a drive mechanism 30a disposed within the housing 100a, and a chuck assembly 40a driven by the drive mechanism. The motor 20a includes a motor shaft 31a, the transmission mechanism 30a includes a first stage planetary gear train a adjacent to the motor 20a, the first stage planetary gear train a includes a first sun gear 310a provided on the motor shaft 31a, a first planetary gear 311a engaged with the first sun gear 310a, and a first output ring gear 312a coupled with the first planetary gear, and the transmission mechanism 30a is capable of transmitting the power of the motor 20a to the chuck assembly 40 a. The housing 100a includes a gear box housing enclosing the transmission mechanism 30a, the gear box housing includes a gear box rear end cover 101a disposed adjacent to the motor 20a, the power tool further includes a support bearing 50a for supporting the motor 20a and located between the transmission mechanism 30a and the motor 20a, in order to limit the movement of the motor 20a toward the working component, the rear cover 101a of the gearbox is at least partially located on the side of the first bearing 50a away from the motor, in other words, the rear cover 101a of the gearbox occupies a part of the axial length because it needs to axially limit the bearing, which will increase the length of the whole machine, and in addition, since there is wear of the first planet 311a between the rotation and the gearbox rear end cover 101a, therefore, a gasket 313a is arranged between the first planetary wheel 311a and the rear end cover 101a of the gearbox, and the existence of the gasket not only makes the structure of the whole machine complex and the assembly cumbersome, but also increases the axial length of the whole machine.

Referring to fig. 1b, a prior art hand held power drill 10b has a housing 100b, the housing 100b being formed of two half-shells, i.e. the housing 100b has no separately provided rear end cap; such half-shells are typically ribbed on their inner side to form a support base 24 for supporting the rear support bearing 50b of the motor shaft. The stator 22 of the brushless motor 20b is disposed around the rotor 21, and the length of the stator 22 in the axial direction of the motor shaft exceeds the length of the rotor 22, and the end of the stator 22 near the housing is further provided with a stator end plate 23, and hall elements (not shown in the figure) for controlling the brushless motor 20b are integrated on the stator end plate 23. The stator end plate 23 is located on the rear side of the stator 22 in the motor shaft axial direction, and the rear support bearing 50b is located on the rear side of the stator end plate 23; the stator 22, the stator end plate 23, and the rear support shaft 50b are arranged in this order along the motor shaft axial direction, and the brushless hall motor 20b occupies a relatively large axial space in the housing, compared to a brushless hall motor.

SUMMERY OF THE UTILITY MODEL

In view of the above, there is a need to provide a handheld power tool with a simple and compact structure.

The technical scheme of the application is realized as follows: a hand-held power tool comprising: a case including a housing formed with a handle portion; a motor disposed within the housing, the motor including a motor shaft for providing rotational power; the supporting device comprises a first supporting piece and a second supporting piece which are respectively arranged at two ends of the motor shaft and used for supporting the motor shaft; an output shaft at least partially received in the housing for mating with a working member; the transmission mechanism is used for transmitting the rotating power of the motor shaft to the output shaft and comprises at least one stage of planetary gear train; the casing further comprises a box body used for accommodating at least part of the transmission mechanism, the box body is provided with an end cover, the end cover is located between the motor and the transmission mechanism along the axial direction of the motor shaft, an accommodating part used for accommodating at least part of the first supporting piece is arranged on the end cover, and the accommodating part is used for supporting the first supporting piece; the planetary gear train comprises a first-stage planetary gear and a first speed change gear which is fixedly arranged relative to the box body, the first speed change gear comprises a main body part and a side wall part which is positioned on one side of the main body part, an inner gear ring which is meshed with the first-stage planetary gear is arranged on the inner side of the main body part, the side wall part radially extends between the end cover and the planetary gear, and the first supporting piece is axially abutted to the side wall part.

Preferably, the end cap is flush with the outer end face of the first support on the same side of the transmission.

Preferably, the first speed change gear is made of metal, and the first support is configured as a first bearing.

Preferably, the thickness of the first speed change gear in the axial direction of the motor shaft is between 4mm and 5mm, and the thickness of the side wall portion in the axial direction of the motor shaft is between 0.8mm and 1.2 mm.

Preferably, the first speed change gear is machined or powder metallurgically formed.

Preferably, the case is made of plastic, and the first speed change gear is used as an insert of the case and is integrally formed with the case through an injection molding process.

Preferably, the motor is a brushless hall-free motor, the hand-held tool further comprises a control board electrically connected with the motor, the control board is arranged on one side of the motor close to the handle part, and the control board is overlapped with the projection of the transmission mechanism in the axial direction of the motor shaft. The control plate is arranged obliquely relative to the motor shaft.

Preferably, the housing further comprises a first half shell and a second half shell in a half-shell manner, and a tail cover far away from the working component, wherein the tail cover is connected with the first half shell and the second half shell through fasteners. The tail cover is internally provided with a containing groove for containing the second supporting piece, the containing groove is provided with an opening facing the motor, and the second supporting piece can enter the containing groove from the opening and is abutted against the bottom wall of the containing groove deviating from the opening in the axial direction of the output shaft.

The main body part and the side wall part of the first speed change gear respectively bear different functions, the main body part is used for being meshed with the planet wheel and connected in a matched mode, the side wall part axially limits the motor shaft, and meanwhile the main body part serves as a gasket (the first planet wheel is prevented from wearing the rear end cover in the rotating process), so that the whole structure is compact, and the assembly is convenient. The motor adopts brushless no hall motor for second support piece can be closer to the rotor setting, and the casing adopts half shell of huff formula plus the mode that sets up of tail-hood, and the medial surface shaping of tail-hood goes out recess and second support piece shape matching and supports it, and second support piece overlaps along motor shaft axial projection with the stator, and axial distance shortens, great reduction the axial dimension of motor to casing tail end. In addition, the control board electrically connected with the motor is arranged on one side of the motor close to the handle part, and the control board is arranged along the axial direction of the motor shaft and is overlapped with the projection of the transmission mechanism on the axial direction of the motor shaft, so that the control board does not occupy the extra axial space of the shell; the axial size of the power tool is short, the length of the whole machine is shortened, and the operation in a narrow space is more convenient.

Drawings

FIG. 1a is a schematic, partially cross-sectional view of a prior art power tool;

FIG. 1b is a schematic partial top view of a prior art power tool;

FIG. 2 is an exploded view of the power tool of the present invention;

fig. 3 is a schematic perspective view of the power tool of the present invention;

FIG. 4 is a schematic, partially cross-sectional view of the power tool of FIG. 2 in accordance with the present invention;

fig. 5 is a partial enlarged view of a portion a in fig. 4 according to the present invention;

fig. 6 is a schematic perspective view of the tail cap of the power tool of the present invention.

Fig. 7 is a schematic view of the front view direction of the power tool of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

As shown in fig. 2 to 5, the present embodiment specifically illustrates a screw driver 10, which includes a housing 100, wherein the housing 100 includes a main housing 108 extending along an axial direction of an output shaft 50 and a handle 106 disposed at an angle to the main housing 108. The casing 100 includes a housing and a box 101, the motor 20 is located in the housing, the transmission mechanism 30 is at least partially accommodated in the box 101, and the chuck assembly 40 driven by the transmission mechanism 30 is disposed at one end of the housing. The motor 20 comprises a motor shaft 31, the transmission mechanism 30 comprises at least a first stage planetary gear train arranged adjacent to the motor 20, the first stage planetary gear train comprises a first sun gear 310 arranged on the motor shaft 31, a first planetary gear 311 engaged with the first sun gear 310, a first change gear 312 fixedly arranged relative to the box body and a first planet carrier, and the first planetary gear 311 is movably arranged on the first planet carrier. The first speed change gear 312 of the present embodiment includes a main body portion and a side wall portion 314 on the side of the main body portion, and a first output ring gear 313 that meshes with the primary planetary gear is provided inside the main body portion. The transmission mechanism further comprises a second stage planetary gear train 32 and a third stage planetary gear train 33, wherein the second stage planetary gear train 32 comprises a second sun gear 320 arranged on the first planet carrier, a second planet gear 321 engaged with the second sun gear 320, and a second output ring gear 322 engaged with the second planet gear 321, and the second planet gear 321 is movably arranged on the second planet carrier. The third stage planetary gear train 33 includes a third sun gear 330 provided to the second carrier, a third planetary gear 331 meshed with the third sun gear 330, and a third output ring gear 332 meshed with the third planetary gear 331. The screwdriver 10 further comprises an output shaft 50 connected with the third planet carrier in a rotating direction (i.e. driven to rotate by the third planet carrier), the output shaft 50 is used for matching with a working component, preferably, in the embodiment, a second output ring gear 322 is movable along the axial direction of the output shaft 50 between a first position close to the first speed change gear 312 and a second position far from the first speed change gear 312 to change the transmission ratio of the transmission mechanism 30, when the second output ring gear 322 is located at the first position, the second output ring gear 322 is rotatably arranged relative to the machine shell, the second output ring gear 322 is simultaneously engaged with the first planet carrier and the second planet gears 321, the transmission ratio of the no speed reduction output or output of the second-stage planetary gear train is 1, when the second output ring gear 322 is located at the second position, the second output ring gear 322 is engaged with the second planet gears but disengaged from the first planet carrier, and the second output ring gear 322 is non-rotatably disposed with respect to the casing 100, at which time the second stage planetary gear train decelerates the rotational motion of the first carrier at a specific gear ratio (less than 1) and transmits it to the second carrier.

With continued reference to fig. 4 and 5, as can be seen from the above description, the transmission mechanism 30 needs to transmit the rotation power of the motor shaft 31 to the output shaft 50 through the rotation of the gears, and in order to ensure smooth transmission between the gears, usually, a large amount of lubricating oil exists in the transmission mechanism 30, and the casing 101 can prevent the lubricating oil from seeping out or leaking out.

In the present embodiment, the motor shaft 31 is disposed coaxially with the output shaft 50; the casing 101 includes a first gear housing 1010 and a second gear housing 1011 which are axially butted against each other along the output shaft 50, wherein the first gear housing 1010 includes a rear end cover 1012 and a first cylindrical housing 1013 on a side of the transmission mechanism 30 away from the working parts, and the rear end cover 1012 and the first cylindrical housing 1013 are integrally formed, which can effectively prevent grease in the transmission mechanism 30 from leaking out from a joint between the first cylindrical housing 1013 and the rear end cover 1012.

The screwdriver 10 further includes a first support and a second support provided at both ends of the motor shaft 31 for rotatably supporting the motor to the housing, wherein the first support is located between the motor 20 and the transmission mechanism 30 in the axial direction of the output shaft 50. In the present embodiment, the side wall portion 314 axially abuts against the first support to prevent the first support and the motor 20 from moving in a direction approaching the working component, in other words, the side wall portion 314 is located on a side of the first support (the first ring gear 313) approaching the motor 20 and axially abuts against the first support to prevent the first support and the motor 20 from moving in a direction approaching the working component. In this embodiment, the first speed-changing gear 312 enables the main body portion and the sidewall portion 314 to respectively perform different functions, the main body portion is used for being engaged and coupled with the primary planet gear, and the motor shaft of the sidewall portion 314 is axially limited. In this embodiment, the rear end cap 1012 is flush with the end surface of the first support member facing the same side of the transmission mechanism. In one embodiment, sidewall portion 314 is formed of a metal material. In another embodiment, the body portion of the first transmission gear 312 and the sidewall 314 are integrally formed as a metal material, so that the manufacture and assembly are convenient, and the wear of the rear cover 1012 caused by the first planet wheel 311 during rotation can be effectively prevented. Therefore, in the present embodiment, the sidewall portion 314 can serve as both a spacer (preventing the first planet wheel 311 from wearing the rear end cover 1012 during rotation) and an axial positioning function for the first support and the motor 20, and compared with the prior art shown in fig. 1a, the rear end cover 1012 of the present application receives and supports the first support, and can at least partially overlap with the first support along the axial direction of the output shaft 50, and the first support occupies a part of the axial space of the rear end cover 102, so that the axial dimension of the casing 101 can be made shorter. In the present embodiment, the first ring gear 313 and the side wall portion 314 are fixedly connected or integrally formed, and the first speed change gear 312 including the first ring gear 313 and the side wall portion 314 may be formed by powder metallurgy or machining.

In addition, in the present embodiment, since the first ring gear 313 and the side wall portion 314 are fixedly connected or integrally molded, the first speed change gear 312 is used as an insert of the first gear case 1010, and the first speed change gear 312 and the first gear case 1010 are integrally molded by an injection molding process, that is, the first speed change gear 312 is previously loaded in a mold, and then a resin and a molten material are injected and joined to the insert to form one piece. Thus, the rear cover 1012 and the first cylindrical housing 1013 of the present embodiment can be integrally formed, and the problem of oil leakage due to the seam between the rear cover 1012 and the first cylindrical housing is avoided.

Referring to fig. 2, in the present embodiment, the casing 100 includes a first half casing 103 and a second half casing 104, and a tail cover 105 abutting against the closed half casing after the first half casing 103 and the second half casing 104 are closed, and the tail cover 105 may be fastened and coupled with the first and second half casings 103, 104 by screws or other fasteners. Referring to FIG. 6, the tail cap 105 is provided with a bearing socket 1051 for receiving the second support member, the bearing socket 1051 having an opening facing the working member such that the second support member and the motor 20 are axially retained by the tail cap 1051.

Referring to fig. 4, the second support in this embodiment is provided as a second bearing 35, and the first support is provided as a first bearing 34; in the second bearing 35, compared with the rear support bearing 50b of the prior art design shown in fig. 1b, since the stator end plate is omitted from the rear side of the stator 22 ', the second bearing 35 is disposed closer to the rotor 21 ' of the motor 20 than the rear support bearing 50b, and the projection of the second bearing 35 and the stator 22 ' along the axial direction of the motor shaft overlaps. The axial distance occupied by the motor 20 and its support means is shortened and, in addition, the design of the shape matching of the bearing socket 1051 of the tail cap 105 and the second bearing 35, the axial dimension from the motor 20 to the tail end of the housing is greatly reduced.

With continued reference to fig. 2 and 3, the first and second half housings 103, 104 include a handle portion 106 for gripping by an operator, the handle portion 106 having disposed thereon a switch assembly for controlling the motor 20, the switch assembly including the switch 60 and a trigger for controlling the switch 60. The power tool also includes a battery pack 70 for powering the motor 20. The end of the handle portion 106 remote from the main housing portion 108 is provided with an opening 106a for mounting the battery pack 70, the battery pack 70 is provided with an end cap 70a, when the battery pack 70 is mounted on the handle portion, the battery pack 70 is at least partially received in the handle portion 106, and the end cap 70a covers the opening 106 a. The battery pack 70 is fitted into the handle portion 106 in the axial direction of the handle portion 106 to make the entire machine more compact.

Referring to fig. 7, the screwdriver 10 is provided with a control board 90 for controlling the brushless hall-less motor 20, the control board 90 being located on the side of the motor 20 of the main housing part 108 near the handle part 106, i.e. between the switch 60 and the transmission mechanism 30. The control plate 90 extends axially along the motor shaft but has an inclination with respect to the motor shaft 31. The control board 90 is disposed to fully utilize the space between the switch 60 and the motor 20 and the transmission mechanism 30, such that the control board 90 and the transmission mechanism and the projection of the motor 20 in the axial direction of the motor shaft at least partially overlap without occupying additional axial space of the housing, such that the screwdriver, which is axially short, comprises a first end coupled to the output shaft 50, a second end disposed opposite to the first end for clamping a working component (not shown), and a plurality of clamping jaws 42 movably disposed at the second end, the second end being disposed with a chuck end face 40a, and the plurality of clamping jaws 42 being operable to extend out of or retract into the chuck end face 40 a; the distance L from the tail cover 105 end to the chuck end face 40a of the chuck component along the axial direction of the output shaft 50 of the screwdriver 10 is set to be in the range of 140mm to 160 mm; preferably, the distance L is not greater than 150mm, in this embodiment 149 mm. When the battery pack 70 is inserted into the handle portion 106, the free end of the handle portion 106 is the end of the end cap 70a of the battery pack 70. The distance H1 from the end of the handle portion 106 far away from the main housing portion 108 to the axis of the output shaft is set within the range of 140 mm-160 mm, and preferably the distance H1 is not more than 158mm, so that the size is suitable for man-machine operation, is suitable for holding operation and convenient carrying, and has small packaging size and low transportation cost.

In order to control the overall size and ratio of the screwdriver 10 and to achieve miniaturization, the chuck assembly 40 is designed to control its axial dimension. The output shaft 50 is provided with a mounting boss 50a at the part matched and connected with the first end of the chuck component 40, the outer end surface of the mounting boss 50a is approximately flush with the outer end surface of the main shell part 108, and the distance L1 from the outer end surface of the mounting boss 50a to the chuck end surface 40a of the chuck component is controlled to be between 41mm and 51 mm; preferably, the distance L1 is not greater than 50mm, 48.3mm in this embodiment. The rear end cover 1012 of the gearbox housing 101 is substantially flush with the end face of the first bearing 34 facing the same side of the transmission 30. The distance L2 from the outer end face of the mounting boss 50a to the end face of the rear end cover 1012 facing the transmission mechanism is controlled to be between 50mm and 55 mm; preferably, the distance L2 is not greater than 53mm, 52mm in this embodiment. The distance L3 from the side end face of the rear end cover 1012 facing the transmission mechanism to the outer end face of the second bearing 35 facing the tail cover 105 is controlled to be between 41mm and 46mm, preferably the distance L3 is not more than 42mm, and 41mm is adopted in the embodiment.

Referring to fig. 3 and 7, the screwdriver 10 further includes a cooling fan 92 located between the motor 20 and the transmission mechanism 30 along the axial direction of the output shaft, a plurality of air inlets 110 are disposed on the tail cover 105 of the main housing 108 away from the working component, a plurality of first air outlets 112 are disposed on the main housing 108 along the circumferential direction at positions corresponding to the cooling fan 92, and a plurality of second air outlets 114 are disposed on two side surfaces of the handle 106 at positions corresponding to the control board 90. Wherein the cooling air (airflow) flows from the air inlet through the inside of the motor 20 under the action of the fan 92, and flows out from the first air outlet and the second air outlet 114 to cool the motor 20 and the control board 90. The miniaturized design makes the inside motor 20 of shell and the generating heat of control panel 90 to be given off fast, and the life-span of machine is influenced to the good or bad of cooling effect, consequently, such mode of setting up of air intake and air outlet has fully considered motor 20 and control panel 90's heat dissipation demand in this embodiment, is different from the heat radiation structure of the screwdriver among the prior art.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the utility model. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. A hand-held power tool comprising:

a case including a housing formed with a handle portion;

a motor disposed within the housing, the motor including a motor shaft for providing rotational power;

the supporting device comprises a first supporting piece and a second supporting piece which are respectively arranged at two ends of the motor shaft and used for supporting the motor shaft;

an output shaft at least partially received in the housing for mating with a working member;

the transmission mechanism is used for transmitting the rotating power of the motor shaft to the output shaft and comprises at least one stage of planetary gear train;

the method is characterized in that: the casing further comprises a box body used for accommodating at least part of the transmission mechanism, the box body is provided with an end cover, the end cover is located between the motor and the transmission mechanism along the axial direction of the motor shaft, an accommodating part used for accommodating at least part of the first supporting piece is arranged on the end cover, and the accommodating part is used for supporting the first supporting piece; the planetary gear train comprises a first-stage planetary gear and a first speed change gear which is fixedly arranged relative to the box body, the first speed change gear comprises a main body part and a side wall part which is positioned on one side of the main body part, an inner gear ring which is meshed with the first-stage planetary gear is arranged on the inner side of the main body part, the side wall part radially extends between the end cover and the planetary gear, and the first supporting piece is axially abutted to the side wall part.

2. The hand-held power tool of claim 1, wherein the end cap is flush with an end surface of the first support member facing the same side of the transmission.

3. The hand-held power tool of claim 1, wherein the first ratio gear is a metal and the first support member is configured as a first bearing.

4. The hand-held power tool according to claim 1, wherein the first speed change gear has a thickness in the motor shaft axial direction of between 4mm and 5mm, and the side wall portion has a thickness in the motor shaft axial direction of between 0.8mm and 1.2 mm.

5. The hand-held power tool of claim 1, wherein the first ratio gear is machined by machining or powder metallurgy.

6. The hand-held power tool of claim 1, wherein the housing is plastic, and the first ratio gear is an insert of the housing and is integrally formed with the housing by an injection molding process.

7. The hand-held power tool of claim 1, wherein the motor is a brushless hall-less motor, the hand-held power tool further comprising a control board electrically connected to the motor, the control board being disposed on a side of the motor adjacent to the handle portion, the control board overlapping a projection of the transmission mechanism in an axial direction of the motor shaft.

8. The hand-held power tool of claim 7, wherein the control plate is disposed obliquely relative to the motor shaft.

9. The hand-held power tool of claim 1, wherein the housing further comprises a first half-shell in the form of a half-shell, a second half-shell, and a tail cap remote from the working component, the tail cap being connected to the first half-shell and the second half-shell by fasteners.

10. The hand-held power tool of claim 9, wherein the tail cap defines a receiving cavity therein for receiving the second support member, the receiving cavity having an opening facing the motor, the second support member being capable of entering the receiving cavity from within the opening and abutting against a bottom wall of the receiving cavity facing away from the opening in the axial direction of the output shaft.

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