CN107471044A

CN107471044A - Hand held electric tool

Info

Publication number: CN107471044A
Application number: CN201610754467.4A
Authority: CN
Inventors: 魏为; 张锐
Original assignee: Nanjing Chervon Industry Co Ltd
Current assignee: Nanjing Chervon Industry Co Ltd
Priority date: 2016-06-08
Filing date: 2016-08-29
Publication date: 2017-12-15

Abstract

The invention discloses a kind of hand held electric tool, including：Output shaft, for fixing polishing pad；Motor, including for driving the drive shaft of output shaft rotation；Transmission mechanism, connect drive shaft and output shaft；Housing, for fixing motor；Brake apparatus, for braking motor；Wherein, transmission mechanism is arranged at one end of drive shaft, and brake apparatus is arranged at the other end of drive shaft.Hand held electric tool disclosed by the invention, can fast braking prevent polishing pad from being damaged to human body.

Description

Hand-held electric tool

Technical Field

The invention relates to a handheld electric tool, in particular to a handheld electric tool with a braking device.

Background

The power tool includes a motor. The motor is used for the working attachment to perform a tool function. When a motor is used in a power source, the power tool may also be referred to as a hand-held power tool.

An angle grinder is a hand-held power tool, and a polishing disc is a working accessory of the angle grinder and is commonly used for cutting and polishing. When the user closes or releases the switch, the sanding disc needs to be stopped quickly to prevent injury from human accidental contact.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention aims to provide a handheld electric tool capable of braking rapidly.

In order to achieve the above object, the present invention adopts the following technical solutions:

a hand-held power tool comprising: the output shaft is used for fixing the polishing disc; the motor comprises a driving shaft for driving the output shaft to rotate; the transmission mechanism is connected with the driving shaft and the output shaft; a housing for fixing the motor; the braking device is used for braking the motor; wherein, drive mechanism sets up in the one end of drive shaft, and arresting gear sets up in the other end of drive shaft.

Further, the braking device includes: and the electromagnet enables the braking device to be in a closed state when the motor is in a power-on state.

Further, the hand-held power tool further includes: an operation switch for starting or stopping the motor; when the operation switch is triggered, the motor and the electromagnet are electrified.

Further, the braking device further includes: a flange member fixed to an end of the driving shaft; the brake assembly is used for contacting the brake motor with the flange piece; when the electromagnet is electrified, acting force for separating the brake assembly from the flange piece is applied to the brake assembly.

Further, the braking device further includes: an elastic member for applying an acting force to the braking member to bring the braking member into contact with the flange member; when the electromagnet is powered off, the elastic piece enables the brake assembly and the flange piece to contact the brake motor.

Further, the braking device further includes: a guide post for guiding movement of the brake assembly relative to the flange member; the direction of movement of the brake assembly relative to the flange member is parallel to the axis of rotation of the drive shaft.

Further, the brake assembly includes: the friction piece is used for braking the motor in a friction mode with the flange piece; a support member for fixing the friction member; the support member can be attracted by the electromagnet to separate the friction member and the flange member.

Further, the flange member is formed with a braking surface that engages the friction member; the braking surface is perpendicular to the axis of rotation of the drive shaft.

Further, the hand-held power tool further includes: a handle for holding by a user; the braking device is arranged between the handle and the motor.

Further, a fan for cooling the motor; the fan and the brake device are respectively arranged at two ends of the driving shaft.

Furthermore, the shell is provided with an air inlet and an air outlet; the fan drives the air current to flow through air inlet, arresting gear, fan and air outlet in proper order.

The invention has the advantages that the position of the braking device effectively utilizes the space inside the shell, and the size of the whole machine is reduced; meanwhile, the braking device directly acts on the driving shaft to quickly brake and avoid danger.

Drawings

FIG. 1 is a schematic view of a hand-held power tool as an embodiment;

FIG. 2 is a schematic view of another perspective of the hand held power tool of FIG. 1;

FIG. 3 is a plan view of the hand held power tool of FIG. 1;

FIG. 4 is a cross-sectional view of the hand held power tool of FIG. 1;

FIG. 5 is an exploded view of the hand held power tool of FIG. 1;

FIG. 6 is an enlarged partial view of the hand held power tool of FIG. 4;

FIG. 7 is a schematic view of the flange member of the hand held power tool of FIG. 4 in contact with the friction member;

fig. 8 is a partial enlarged view of the structure of fig. 6.

Detailed Description

As shown in fig. 1 to 4, a hand-held electric tool 100 includes: the grinding disc 10, the shield 20, the output shaft 30, the motor 40, the handle 50, the transmission mechanism 60, the housing 70 and the brake device 80. Specifically, the hand-held power tool 100 is an angle grinder.

A sanding disc 10 for performing a tool function such as sanding or cutting. The guard 20 at least partially covers the sanding disc 10 for a protective function. The hand-held power tool 100 further includes a quick-clamping mechanism 21, and the quick-clamping mechanism 21 is used for quickly mounting or dismounting the shield 20 and also can be used for adjusting the position of the shield 20. The output shaft 30 is used to mount or secure the sanding disc 10. The motor 40 drives the output shaft 30 to rotate. The motor 40 includes a drive shaft 41, a rotor 42, and a stator 43. The rotor 42 rotates relative to the stator 43. The drive shaft 41 may also be referred to as a motor shaft. The transmission mechanism 60 is used to connect the output shaft 30 and the drive shaft 41 and transmit the driving force of the drive shaft 41 to the output shaft 30. The housing 70 is used to mount or fix the motor 40. The handle 50 is held by a user. The handle 50 may be formed as a separate part or may be formed from the housing 70. The housing 70 includes a head case 71 and a chassis 72. The motor 40 is fixed to the housing 72. The head case 71 is used to mount the transmission mechanism 60. The transmission mechanism 60 includes: a first gear 61 and a second gear 62. The first gear 61 is connected to the drive shaft 41, and the second gear 62 is connected to the output shaft 30. The first gear 61 and the second gear 62 are engaged, so that the drive shaft 41 rotates the output shaft 30. The axis of rotation of the drive shaft 41 is perpendicular to the axis of rotation of the output shaft 30. The head case 71 is formed with attachment holes 711a, 711b, and 711c for attaching auxiliary handles. A plurality of mounting holes 711a, 711b, 711c are provided at different positions of the head housing 71 to accommodate different working conditions or different user's demands.

The motor 40 may be driven by direct current or alternating current. That is, the motor 40 may be either a dc motor or an ac motor. The hand-held power tool 100 further includes an operation switch 51 for turning on or off the motor 40. The motor 40 is activated when the operation switch 51 is activated, and the motor 40 is deactivated when the operation switch 51 is released. The operation switch 51 is provided on the handle 50. The hand held power tool 100 also includes a power cord 90 for powering the motor 40. As another embodiment, an internal combustion engine powered by fuel combustion may be used in place of the electric motor 40 powered by electric power. Specifically, the power of the hand-held power tool 100 is greater than 2000w and less than 3000 w.

The braking device 80 is used to brake the motor 40. The motor 40 can be quickly stopped. The transmission mechanism 60 is provided at one end of the drive shaft 41, and the brake device 80 is provided at the other end of the drive shaft 41. The brake 80 is disposed between the handle 50 and the motor 40. The position of the braking device 80 can effectively utilize the space inside the housing 70, and the size of the whole machine can be reduced. At the same time, the braking device 80 directly acts on the driving shaft 41 to brake rapidly. The braking device 80 stops the motor 40 in a short time when the user needs to stop the rotation of the polishing sheet 10, thereby preventing danger.

The fan 75 is used to cool the motor 40. The fan 75 and the brake 80 are respectively provided at both ends of the drive shaft 41. The housing 72 is formed with an intake opening 73 and an exhaust opening 74. The fan 75 drives the airflow to flow through the air inlet 73, the braking device 80, the fan 75 and the air outlet 74 in sequence. The air flow generated by the fan 75 can cool not only the motor 40 but also the brake device 80.

As shown in fig. 4 to 7, the braking device 80 includes an electromagnet 81, an elastic member 82, a flange member 83, and a braking member 84.

When the operation switch 51 is activated, the motor 40 and the electromagnet 81 are energized, that is, the motor 40 is in an energized state, and the electromagnet 81 is in an energized state, at which time the brake device 80 is in a closed device, that is, the non-brake device 80. When the user releases the operating switch 51, the motor 40 is turned off, and the electromagnet 81 is turned off, and the braking device 80 is in a braking state, so that the motor 40 is rapidly stopped.

Specifically, the flange member 83 is provided at an end portion of the drive shaft 41. The flange member 83 is provided at the end of the drive shaft 41 remote from the end of the transmission mechanism 60. The flange member 83 is fixed to the end of the drive shaft 41. The brake assembly 84 is adapted to contact the flange member 83 to brake the motor 40.

The resilient member 82 applies a force to the brake assembly 84 that causes the brake assembly 84 to contact the flange member 83. When the electromagnet 81 is not energized, or when the electromagnet 81 is de-energized, the elastic member 82 presses the braking member 84 so that the braking member 84 contacts the flange member 83 to prevent the rotation of the drive shaft 41. Specifically, the elastic member 82 is a spring.

Electromagnet 81, when energized, can apply a force to brake assembly 84 that separates brake assembly 84 from flange member 83. That is, the force applied by electromagnet 81 to brake assembly 84 is in the opposite direction of the force applied by resilient member 82 to brake assembly 84.

When the electromagnet 81 is de-energized, the braking member 84 moves toward the flange member 83 by the elastic member 82 so that the friction member 841 contacts the braking surface 831 to rapidly stop the driving shaft 41.

As an alternative embodiment the brake assembly 84 may be provided as a wear resistant material. As a specific embodiment, the brake assembly 84 includes a friction member 841 and a support member 842. The friction member 841 rubs the brake motor 40 with the flange member 83, and the support member 842 is used to fix the friction member 841. The friction member 841 is made of a wear-resistant material. Specifically, the flange member 83 is formed with a braking surface 831 fitted with the friction member 841. The braking surface 831 is perpendicular to the axis of rotation of the drive shaft 41. The support 842 is made of a metal material, and specifically, the support 842 can be attracted by the electromagnet 81 to separate the friction member 841 and the flange member 83. The brake 80 also includes a guide post 85. The guide post 85 serves to guide the movement of the brake assembly 84 relative to the flange member 83. The direction of movement of the brake assembly 84 relative to the flange member 83 is parallel to the axis of rotation of the drive shaft 41. The guide post 85 is fixed to the housing 70. The support 842 is formed with a notch 843 that mates with the guide post 85.

Fig. 6 is a partially enlarged view of fig. 4, and fig. 6 shows a state in which the electromagnet 81 is in an energized state. At this time, the attraction force of the electromagnet 81 is greater than the elastic force of the elastic member 82, that is, the electromagnet 81 attracts the support member 841 to the right against the elastic force of the elastic member 82. Bringing the flange member 83 away from the friction member 841. As shown in fig. 8, the maximum clearance L1 between the friction member 841 and the flange member 83 is 0.1mm or more and 5mm or less. Further, L1 is 0.1mm or more and 2mm or less. Further, L1 is 0.1mm or more and 1mm or less. Further, L1 is 0.1mm or more and 0.5mm or less. Further, L1 is 0.1mm or more and 0.3mm or less. L1 is sized so that friction member 741 can be quickly separated from flange member 83 when motor 40 is activated. Meanwhile, when the motor 40 is turned off, the friction member 741 and the flange member 83 can be quickly combined to perform friction braking.

Fig. 7 shows a state in which the electromagnet 81 is in an off state, and the electromagnet 81 has no suction force or a suction force smaller than the urging force of the elastic member 82. When the electromagnet 81 is turned off, the supporting member 841 is moved leftward by the elastic member 82 until the friction member 841 is in contact with the flange member 83, and the driving shaft 41 is rapidly stopped by the frictional force between the friction member 841 and the flange member 83. At this time, the guide post 85 not only guides the movement of the support 842, but also the torsion of the driving shaft 41 is transmitted to the support 842 through the friction member 741. The guide post 85 prevents rotation of the support 842. As another embodiment, an additional stopper may be provided to prevent the rotation of the support 842.

As another embodiment, the braking device may not be provided with the elastic member. The position of the brake assembly relative to the flange member is controlled by an electromagnet. The brake assembly is kept in contact with the flange piece by the acting force of the electromagnet to brake.

The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It should be understood by those skilled in the art that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by using equivalent alternatives or equivalent variations fall within the scope of the present invention.

Claims

1. A hand-held power tool comprising:

the output shaft is used for fixing the polishing disc;

the motor comprises a driving shaft for driving the output shaft to rotate;

a transmission mechanism connecting the drive shaft and the output shaft;

a housing for fixing the motor;

a brake device for braking the motor;

wherein,

the transmission mechanism is arranged at one end of the driving shaft, and the braking device is arranged at the other end of the driving shaft.

2. The hand-held power tool of claim 1, wherein:

the braking device includes:

and the electromagnet enables the braking device to be in a closed state when the motor is in a power-on state.

3. The hand-held power tool of claim 2, wherein:

the hand-held power tool further includes:

the operation switch is used for starting or closing the motor;

when the operation switch is triggered, the motor and the electromagnet are electrified.

4. The hand-held power tool of claim 1, wherein:

the braking device further includes:

a flange member fixed to an end of the driving shaft;

the brake assembly is used for contacting with the flange piece to brake the motor;

and when the electromagnet is electrified, acting force for separating the brake assembly from the flange piece is applied to the brake assembly.

5. The hand-held power tool of claim 4, wherein:

the braking device further includes:

an elastic member for applying a force to the brake assembly to bring the brake assembly into contact with the flange member;

when the electromagnet is powered off, the elastic piece enables the braking assembly to be in contact with the flange piece to brake the motor.

6. The hand-held power tool of claim 4, wherein:

the braking device further includes:

a guide post for guiding movement of the brake assembly relative to the flange member;

the direction of movement of the brake assembly relative to the flange member is parallel to the axis of rotation of the drive shaft.

7. The hand-held power tool of claim 4, wherein:

the brake assembly includes:

the friction piece and the flange piece are used for braking the motor in a friction mode;

a support member for fixing the friction member;

the support member is attracted by the electromagnet to separate the friction member and the flange member.

8. The hand-held power tool of claim 7, wherein:

the flange part is provided with a braking surface matched with the friction part;

the braking surface is perpendicular to the axis of rotation of the drive shaft.

9. The hand-held power tool of claim 1, wherein:

the hand-held power tool further includes:

a handle for holding by a user;

the brake device is arranged between the handle and the motor.

10. The hand-held power tool of claim 1, wherein:

a fan for cooling the motor;

the fan and the braking device are respectively arranged at two ends of the driving shaft.

11. The hand-held power tool of claim 10, wherein:

the shell is provided with an air inlet and an air outlet;

the fan drives airflow to sequentially flow through the air inlet, the braking device, the fan and the air outlet.