CN211018481U

CN211018481U - Electric tool

Info

Publication number: CN211018481U
Application number: CN201922223362.8U
Authority: CN
Inventors: 吉绍山; 张响亮; 刘兵建
Original assignee: Positec Power Tools Suzhou Co Ltd
Current assignee: Positec Power Tools Suzhou Co Ltd
Priority date: 2019-12-12
Filing date: 2019-12-12
Publication date: 2020-07-14
Anticipated expiration: 2029-12-12
Also published as: WO2021114897A1

Abstract

The utility model discloses an electric tool, include: the working accessory is used for realizing the operation function; a motor for driving the working attachment; the transmission mechanism is connected with the motor and the working accessory; a housing including a gear case for accommodating the transmission mechanism and a motor case for accommodating the motor; the motor includes: the motor shaft is provided with a front end close to the transmission mechanism and a rear end far away from the front end along the axial direction of the motor shaft; the stator is fixed relative to the shell and comprises a cavity for the motor shaft to pass through; the rotor is sleeved at the periphery of the stator and drives the motor shaft to rotate; a first bearing supporting a front end of a motor shaft; a second bearing located between the front end and the rear end of the motor shaft for supporting the motor shaft within the axial width of the stator; and a third bearing supporting a rear end of the motor shaft on the housing. The electric tool provided in the embodiment of the application can achieve the advantages of small vibration, prolonged service life of the machine and strong practicability when the external rotor motor is applied to cutting operation.

Description

Electric tool

Technical Field

The utility model relates to an electric tool field, in particular to use external rotor electric machine's electric tool.

Background

Circular saws are widely used electric tools, and can use a motor as power to drive a saw blade through a transmission mechanism to perform sawing operation.

The external rotor motor can output larger power and has small volume, and is widely applied to electric tools. The motor shaft of the commonly used external rotor motor is usually supported by two bearings, one is located at the front end of the motor shaft, the other is supported on the stator by the motor shaft in the middle of the motor shaft, the external rotor motor bearings are distributed to enable the rear end of the motor shaft to be in a cantilever structure, and due to the fact that the rotational inertia of the external rotor motor is very large, the swinging of the motor mainly acts on the middle bearing, the vibration is large, the integral stability is poor, the service life of the bearing is shortened, and the motor shaft is easy to break. Especially, once the bearing in the motor has a problem, the bearing is not easy to replace, and the service life of the motor is influenced. The other mode is that one bearing is positioned at the front end of the motor shaft, the other bearing is positioned at the rear end of the motor shaft to support the motor shaft on a tool shell, the rear end of the motor shaft must be supported on a certain shell during testing or use, and application scenes are limited.

In view of the defects in the prior art, there is a need to provide a new external rotor motor, which enables an electric tool to achieve the following effects when the external rotor motor is applied for operation: the vibration is little, and the machine life-span extension, the effect that the practicality is strong.

SUMMERY OF THE UTILITY MODEL

In view of the deficiencies of the prior art, an object of the present application is to provide an electric tool using an external rotor motor, which can achieve the effects of small vibration, long service life of the electric tool, and strong practicability when performing work.

The above object of the present invention can be achieved by the following technical solutions:

a power tool, comprising: the working accessory is used for realizing the operation function; a motor for driving the working attachment; the transmission mechanism is connected with the motor and the working accessory; a housing including a gear case for accommodating the transmission mechanism and a motor case for accommodating a motor; the motor includes: the motor shaft is provided with a front end close to the transmission mechanism and a rear end far away from the front end along the axial direction of the motor shaft; a stator fixed relative to the housing, the stator including a cavity through which the motor shaft passes; the rotor is sleeved on the periphery of the stator and drives the motor shaft to rotate; a first bearing supporting a front end of the motor shaft; a second bearing located between the front and rear ends of the motor shaft supporting the motor shaft over an axial width of the stator; a third bearing supporting a rear end of the motor shaft on the housing.

In a preferred embodiment, the third bearing is further covered with a bearing housing, and the third bearing supports the rear end of the motor shaft on the housing through the bearing housing.

In a preferred embodiment, the electric tool further comprises a blower fan, the blower fan is arranged at the rear end of the rotor and is fixedly connected with the motor shaft, and the blower fan is fixedly connected with the rotor.

In a preferred embodiment, the motor housing is provided with cooling vents, which are located at least partially radially outside the fan.

In a preferred embodiment, the motor further includes a stator support, the stator support includes a support portion for supporting the stator and a fixing portion for fixing to the housing, and the support portion penetrates through the stator and is attached to an inner side wall of the stator.

In a preferred embodiment, the transmission mechanism includes a driving gear, a driven gear and an output shaft which are arranged in the gear box, the inner side wall of the stator supporting part is in clearance fit with the motor shaft, the stator supporting part is provided with a first end close to the gear box and a second end far away from the gear box, the fixing part is provided with a first limiting step used for being matched with the first bearing on the inner side close to the first end, and the supporting part is provided with a second limiting step used for being matched with the second bearing on the inner side close to the second end.

In a preferred embodiment, the material of the stator support is a metallic material.

In a preferred embodiment, the second bearing is a needle bearing.

Advantageous effects

The electric tool that provides uses external rotor electric machine in this application embodiment, and the motor shaft is supported by three bearing, establishes the second bearing in the middle of the motor shaft, supports the motor shaft on the stator, has established the third bearing at the rear end of motor shaft, and this third bearing will the rear end of motor shaft supports on the casing, avoid the motor shaft to be cantilever structure, can balance the effort on the bearing for electric tool vibrates for a short time when using external rotor electric machine to carry out the operation, and the machine life extension, user experience is better, and be convenient for the motor test, be applicable to the inconvenient circumstances that supports the motor shaft tail end of shell simultaneously, and the practicality is strong.

Specific embodiments of the present application are disclosed in detail with reference to the following description and drawings, indicating the manner in which the principles of the application may be employed. It should be understood that the embodiments of the present application are not so limited in scope.

Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments, in combination with or instead of the features of the other embodiments.

It should be emphasized that the term "comprises/comprising" when used herein, is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps or components.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without inventive labor.

FIG. 1 is a schematic side view of a circular saw according to one embodiment of the present application;

FIG. 2 is a schematic view of another side of a circular saw provided in accordance with an embodiment of the present application;

FIG. 3 is a cross-sectional view of a circular saw provided in accordance with one embodiment of the present application;

fig. 4 is a cross-sectional view of a motor provided in an embodiment of the present application.

Description of reference numerals:

1. a base plate;

2. a saw blade;

30. a motor shaft; 301. a front end; 302. a back end; 31. a first bearing; 32. a second bearing; 33. a third bearing; 330. a bearing housing; 35. a stator; 36. a rotor; 37. a fan; 38. a stator support; 380. a fixed part; 381. a first limit step; 382. a second limit step; 383. a support portion;

41. a gear case; 42. a drive gear; 43. a driven gear; 44. an output shaft;

5. a housing; 51. fixing a protective cover; 52. a movable shield; 53. a motor housing; 530. an air outlet; 54. a handle;

6. a battery pack.

Detailed Description

The technical solution of the present invention will be described in detail with reference to the accompanying drawings and specific embodiments, it should be understood that these embodiments are only used for illustrating the present invention and are not used for limiting the scope of the present invention, and after reading the present invention, the modifications of the present invention in various equivalent forms by those skilled in the art will fall within the scope defined by the claims attached to the present application.

It will be understood that when an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. The application specification provides an electric tool applying an outer rotor motor. The electric tool is generally provided with: the working accessory is used for realizing the operation function; a motor for driving the working attachment; the transmission mechanism is connected with the motor and the working accessory; and the shell comprises a gear box for accommodating the transmission mechanism, a motor shell for accommodating the motor and the like.

Compared with the prior art, adopt three bearing to support at the motor shaft, avoid the motor shaft to be cantilever structure, the effort on the balanced bearing to the motor test of being convenient for is applicable to the inconvenient condition that supports the motor shaft tail end of shell simultaneously, has successfully solved prior art's above-mentioned problem, makes electric tool vibrate for a short time when using external rotor motor cutting operation, and the machine life extension, the practicality is strong, and user experience is better.

The present invention is described with reference to an electric circular saw as an example in the present embodiment, but the present invention is not limited to an electric circular saw, and may be other electric tools using an external rotor motor.

Referring to the circular saw shown in fig. 1 to 3, the circular saw may generally include: bottom plate 1, saw blade 2, motor, drive mechanism and casing 5. The housing 5 may include: a gear box 41 for accommodating the transmission mechanism, a fixed shield 51 and a movable shield 52 which cover the outside of the saw blade 2, and a motor housing 53 which covers the outside of the motor. The motor casing 53 is a hollow casing with an open end, and the open end of the motor casing 53 is connected with the fixed shield 51. The base plate 1 abuts against the workpiece and is provided with a slot for the passage of a saw blade 2. Specifically, bottom plate 1, saw bit 2 and drive mechanism etc. can refer to current annular saw, and this application is no longer redundantly described herein.

In one embodiment, the circular saw may be a handheld circular saw. The housing 5 of the circular saw is provided with a handle 54 for the user to hold.

In the embodiments of the present application, the motor portion of the circular saw will be described with emphasis. Referring to fig. 3 and 4, the motor may include: the motor comprises a motor shaft 30, a stator 35, a rotor 36, a first bearing 31, a second bearing 32 and a third bearing 33, wherein the first bearing 31, the second bearing 32 and the third bearing 33 are sleeved on the motor shaft 30.

The motor is an external rotor motor, that is, the rotor 36 is sleeved on the periphery of the stator 35. When the rotor 36 is sleeved on the periphery of the stator 35, the distance from the rotor to the motor shaft 30 is large, so that the concentricity with the motor shaft 30 is not easy to ensure, and the rotational inertia of the motor is easy to be large on the whole.

The motor shaft 30 has a front end 301, which is close to the gear mechanism, and a rear end 302, which is remote from the front end 301, in the longitudinal extension direction thereof. The longitudinal extension direction may be in the axial direction of the motor shaft 30. The motor shaft 30 is sleeved with a first bearing 31, a second bearing 32 and a third bearing 33 in sequence along the axial direction from the front end 301 to the rear end 302.

The first bearing 31 may be sleeved on the motor shaft 30 near the front end 301, and is used for supporting the front end 301 of the motor shaft 30. The motor shaft 30 is provided with a stopper for axially stopping the first bearing 31. The limiting portion may be in the form of a limiting step, and of course, the limiting portion may also be in other forms capable of axially limiting the first bearing 31. When the limiting portion limits the step, the inner side of the first bearing 31 can abut against the limiting step.

In one embodiment, the first bearing 31 is provided on the outside with a stator support 38 for supporting the stator 35. The stator support 38 may be a hollow solid of revolution as a whole. The stator support 38 may be mounted on the motor shaft 30. The stator support 38 may include a support portion 383 for supporting the stator 35 and a fixing portion 380 for fixing to the housing 5.

The support part 383 penetrates the stator 35 along the axial direction of the motor shaft 30 and is attached to the inner wall of the stator 35. The material of the stator supporting member 38 may be a metal material with better thermal conductivity. When the stator supporting member 38 is made of a metal material with a better heat conduction performance, the heat on the stator 35 can be effectively conducted to the transmission mechanism and the housing 5, so that the heat dissipation efficiency of the motor is improved.

Generally, the transmission mechanism may include a driving gear 42, a driven gear 43, and an output shaft 44 provided in the gear case 41. The inner side wall of the stator support 38 is clearance fitted with the motor shaft 30. The stator support 38 has a first end proximal to the gear box 41 and a second end distal to the gear box 41. The fixing portion 380 is provided with a first limit step 381 for matching with the first bearing 31 at an inner side near the first end, and a second limit step 382 for matching with the second bearing 32 at an inner side near the second end.

The second bearing 32 is located between the front end 301 and the rear end 302 of the motor shaft 30, and can be sleeved on the middle of the motor shaft 30, for example. The outer side of the second bearing 32 abuts against the stator support 38 for supporting the stator 35, and supports the motor shaft 30 over the axial width of the stator 35. Specifically, the outer side of the second bearing 32 can abut against the second limit step 382 of the stator support 38.

In particular, the second bearing 32 may be in the form of a needle bearing. The outside dimension of the needle bearing is small, and particularly the radial dimension is small. When the second bearing 32 is a needle bearing, it is interposed between the support base of the stator support 38 and the motor shaft 30, and thus the concentricity is excellent and the radial volume of the motor is small.

Third bearing 33 can overlap and establish and be close to on the motor shaft 30 of rear end 302, be used for with the rear end 302 of motor shaft 30 supports on the casing 5 to avoid motor shaft 30 to be cantilever structure, the effort on the balanced bearing, make the circular saw vibrate for a short time when using outer rotor 36 motor cutting operation, the machine life extension, user experience is better.

In order to further reduce vibration, the third bearing 33 may be covered with a bearing sleeve 330, and the third bearing 33 supports the rear end 302 of the motor shaft 30 on the housing 5 through the bearing sleeve 330.

In one embodiment, the motor may also be provided with a fan 37. The fan 37 is sleeved on the motor shaft 30, and the fan 37 is connected with the rotor 36 and the output shaft 44 at the same time.

In the present embodiment, the rotor 36 may be a sleeve with two open ends, and has a front end and a rear end opposite to each other, wherein the front end of the rotor 36 is an end close to the front end 301 of the motor shaft 30, and the rear end of the rotor 36 is an end close to the rear end 302 of the motor shaft 30. The fan 37 is provided with fan blades, the rear end periphery of the rotor 36 is fixedly connected with the fan blades of the fan 37, the fan 37 is also fixedly connected with the output shaft 44, therefore, the rotor 36 is fixedly connected with the output shaft 44 through a fan, and the layout is more compact in the axial direction of the motor. In addition, the fan rotates with the rotor 36 and the output shaft 44, and causes an air flow into the gap between the rotor 36 and the stator 35, thereby cooling the motor.

Further, an air outlet 530 is disposed on the motor casing 53, the air outlet 530 is located at a side close to the third bearing 33, and the fan 37 is located on the motor shaft 30 between the second bearing 32 and the third bearing 33. When the fan 37 is located near the air outlet 530, it is beneficial to form a concentrated negative pressure at the air outlet 530, so that the heat generated inside the housing 5 can be taken out by the airflow flowing to the air outlet 530 to the greatest extent, thereby achieving an ideal heat dissipation effect.

In this embodiment, the circular saw may be powered by a dc power source or may be powered by an ac power source.

When the circular saw is powered by a dc power source, the circular saw may further include a battery pack 6, and the battery pack 6 may be detachably disposed on the housing 5.

It should be noted that, in the description of the present application, the terms "first", "second", and the like are used for descriptive purposes only and for distinguishing similar objects, and no precedence between the two is intended or should be construed to indicate or imply relative importance. In addition, in the description of the present application, "a plurality" means two or more unless otherwise specified.

The above embodiments in the present specification are all described in a progressive manner, and the same and similar parts among the embodiments may be referred to each other, and each embodiment is described with emphasis on being different from other embodiments.

The above description is only a few embodiments of the present invention, and although the embodiments of the present invention are disclosed as above, the above description is only for the convenience of understanding the present invention, and is not intended to limit the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. An electric power tool, characterized by comprising: the working accessory is used for realizing the operation function; a motor for driving the working attachment; the transmission mechanism is connected with the motor and the working accessory; a housing including a gear case for accommodating the transmission mechanism and a motor case for accommodating a motor; the motor includes:

the motor shaft is provided with a front end close to the transmission mechanism and a rear end far away from the front end along the axial direction of the motor shaft;

a stator fixed relative to the housing, the stator including a cavity through which the motor shaft passes;

the rotor is sleeved on the periphery of the stator and drives the motor shaft to rotate;

a first bearing supporting a front end of the motor shaft;

a second bearing located between the front and rear ends of the motor shaft supporting the motor shaft over an axial width of the stator;

a third bearing supporting a rear end of the motor shaft on the housing.

2. The power tool of claim 1, wherein the third bearing is further housed with a bearing housing, and the third bearing supports the rear end of the motor shaft on the housing through the bearing housing.

3. The power tool of claim 1, further comprising a blower fan disposed at a rear end of the rotor and fixedly coupled to the motor shaft, the blower fan being fixedly coupled to the rotor.

4. The power tool of claim 3, wherein the motor housing is provided with cooling vents at least partially radially outward of the fan.

5. The power tool of claim 1, wherein the motor further comprises a stator support including a support portion for supporting the stator and a fixing portion for fixing to the housing, the support portion extending through the stator and being disposed in abutment with an inner side wall of the stator.

6. The power tool of claim 5, wherein the transmission mechanism includes a drive gear, a driven gear, and an output shaft disposed in the gear box,

the inside wall of the stator supporting part is in clearance fit with the motor shaft, the stator supporting part is provided with a first end close to the gear box and a second end far away from the gear box, the fixing part is close to the inner side of the first end and is provided with a first limiting step used for being matched with the first bearing, and the supporting part is close to the inner side of the second end and is provided with a second limiting step used for being matched with the second bearing.

7. The power tool of claim 5, wherein the material of the stator support is a metallic material.

8. The power tool of claim 1, wherein the second bearing is a needle bearing.