CN111009990A

CN111009990A - Power mechanism and handheld tool applying same

Info

Publication number: CN111009990A
Application number: CN201811168179.6A
Authority: CN
Inventors: 阎宁汉; 谢建雄; 方郁人
Original assignee: Fairway Electronic Co ltd
Current assignee: Fairway Electronic Co ltd
Priority date: 2018-10-08
Filing date: 2018-10-08
Publication date: 2020-04-14

Abstract

A power mechanism and a handheld tool applying the same are provided, wherein the power mechanism comprises a motor, a worm, a planetary gear set and a control plate. The worm is driven by the motor to rotate, the planetary gear set is meshed with the worm, and the control panel is used for controlling the on-off or running state of the motor.

Description

Power mechanism and handheld tool applying same

Technical Field

The present invention relates to a power mechanism and a hand tool using the same, and more particularly, to a power mechanism using a motor as a main power source and a hand tool using the same.

Background

Generally, most of the hand tools on the market directly drive the transmission shaft and the tool members (such as the grinding disc, the drill bit, etc.) by the brush motor, however, the power conversion efficiency of such an arrangement is very poor, for example, the power conversion efficiency of the direct drive using the brush motor is only about 40%. In addition, the prior art hand tool is unstable in controlling the rotation speed, and the torque provided by the prior art hand tool is low.

Therefore, it is an urgent need to provide a power mechanism with high power conversion efficiency, stable rotation speed and high torque and a handheld tool using the same.

Disclosure of Invention

In order to solve the above problems of the prior art, an object of the present invention is to provide a power mechanism with high power conversion efficiency and capable of providing a stable rotation speed and a high torque, and a handheld tool using the power mechanism.

In order to achieve the above object, the power mechanism of the present invention is applied to a handheld tool, and the power mechanism includes a motor, a worm, a planetary gear set and a control board. The worm is driven by the motor to rotate; the planetary gear set is meshed with the worm; and the control panel is used for controlling the on-off or running state of the motor.

In one embodiment, the motor is a brushless dc motor.

In one embodiment, the control board has a magnetic field orientation control function.

In one embodiment, the planetary gear set includes a worm wheel, a sun gear, a plurality of external gears, an external ring gear, and a carrier, wherein the sun gear and the worm wheel are coaxially disposed, the worm wheel is engaged with the worm, and wherein the sun gear and the plurality of external gears are engaged by being assembled to the carrier, and the carrier is configured to be connected to an external transmission shaft.

In one embodiment, the control board further comprises a temperature sensing module for sensing the temperature inside the hand tool.

In one embodiment, when the temperature sensed by the temperature sensing module is greater than a temperature default value, the control board sends a first signal to enable the motor to reduce the rotation speed or stop running.

In one embodiment, the control board further includes a pressure sensing module for sensing a pressure applied to the hand tool.

In one embodiment, when the pressure sensed by the pressure sensing module is greater than a first pressure default value, the control board sends a second signal to make the motor reduce the rotation speed or stop running.

In one embodiment, when the pressure sensed by the pressure sensing module is greater than a second pressure default value, the control board sends a third signal to enable the motor to stop running and start running repeatedly.

In one embodiment, the control panel further includes a rotation speed detection module for feedback-controlling the motor to reach a default rotation speed and determining the operating state of the motor.

In one embodiment, the power mechanism further includes an inner housing, and the worm and the planetary gear set are disposed inside the inner housing.

The invention also provides a handheld tool which comprises an outer shell, the power mechanism, the control interface, the transmission shaft, the tool piece and the power module. The power mechanism is arranged in the outer shell; the control interface is electrically connected with the control board of the power mechanism and used for inputting a control signal; the transmission shaft is linked with the power mechanism; the tool piece is linked with the transmission shaft; and the power module is used for supplying power required by the operation of the power mechanism.

Compared with the prior art, the power mechanism comprises the motor, the worm, the planetary gear set and the control board, the motor provides power, the worm has the functions of power direction conversion, speed reduction and the like, the planetary gear set also has the speed reduction function and excellent transmission efficiency, and because of the characteristics of the worm and the planetary gear set, the power mechanism has high power conversion efficiency and high torque under low-speed output, the operating state of the motor is controlled by the control board to provide rotating speeds suitable for various states, and the brushless direct current motor and the control board with the magnetic field orientation control function can be further used to improve the torque, the power conversion efficiency and more stable rotating speeds again. In addition, the control board of the power mechanism can be additionally provided with a temperature sensing module or a pressure sensing module, so that the risk of abnormal states is reduced. The handheld tool with the power mechanism also has the advantages, and the defects in the prior art are fully overcome.

Drawings

Fig. 1 is an external view of a hand tool according to a first embodiment of the present invention.

Fig. 2 is an exploded view of a power mechanism according to a second embodiment of the present invention.

FIG. 3 is a block diagram of a control board according to a third embodiment of the present invention.

Fig. 4 is an exploded view of a hand tool according to a fourth embodiment of the present invention.

Description of the symbols:

10 Motor

11 worm

12 planetary gear set

120a worm wheel

120b sun gear

121a, 121b, 121c, 121d external gear

122 outer gear ring

123 Gear carrier

13 control panel

130 temperature sensing module

131 pressure sensing module

132 rotating speed detecting module

14a, 14b inner housing

40a, 40b outer casing

41 power mechanism

42a, 42b control interface

43 drive shaft

44 tool parts

45 power supply module

Detailed Description

The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will become apparent to those skilled in the art from the present disclosure. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways.

Referring to fig. 1, fig. 1 is an external view of a handheld tool according to a first embodiment of the present invention. The power mechanism of the present invention is applied to the hand tool shown in fig. 1, and further, the hand tool uses a motor as a main power source and is convenient for hand use.

Generally, hand tools are used for cleaning, grinding, waxing, etc. in which the tool (e.g., brush) contacts the object and generates friction, so that the power mechanism of the hand tool must provide sufficient torque to achieve cleaning effect, as well as other hand tools used for other purposes.

Referring to fig. 2, fig. 2 is an exploded view of a power mechanism according to a second embodiment of the present invention. As shown, the power mechanism of the present invention includes a motor 10, a worm 11, a planetary gear set 12, and a control board 13. The motor 10 is powered, the worm 11 is rotated by the motor 10, the planetary gear set 12 is engaged with the worm 11, and the control board 13 is used to control the on/off or operation state of the motor 10.

The worm 11 can change the power direction, and compared with the configuration that the existing hand tool uses the direct drive of the motor, the hand tool of the invention can install the motor 10 in different directions, and adjust the integral gravity center to be more suitable for hand use. In addition, compared with the speed reduction by using a gear to match with a gear, the speed reduction by matching the worm 11 with the gear is more volume-saving.

The planetary gear set 12 also has a speed reduction function, can further reduce the output speed, and has excellent transmission efficiency, because of the characteristics of the worm 11 and the planetary gear set 12, the power mechanism of the present invention has high power conversion efficiency and high torque at low speed output.

The control board 13 is a circuit board with a control function, and the control board 13 can control the on/off or operation state of the motor 10, including controlling the rotation speed of the motor 10, the prior art design without control board only allows the motor to operate according to a default rotation speed, but the power mechanism of the present invention can control the operation state of the motor 10 by the control board 13 to provide rotation speeds suitable for various states. For example, a slow start design may be provided, in which the motor 10 is gradually increased in speed rather than being accelerated violently when it is turned on, or multiple default speeds may be set.

Further, for example, the control board 13 can also slow down or stop the motor 10 to obtain a larger friction force for the tool, which is sometimes required to handle a particular situation when the hand tool is used for cleaning or polishing, and obtain a larger friction force than the tool can be continuously operated at a high speed when the tool is started from a low speed or stopped, so that the hand tool can obtain a better cleaning or polishing capability by controlling the motor 10 to repeatedly slow down, stop and start by the control board 13.

In one embodiment, the motor 10 may be a brushless direct current motor (BLDC). The brushless dc motor has a higher torque than the brush motor used in the prior art at the same volume, and detects the displacement on the rotor in a trapezoidal shape by means of back electromotive force (voltage is introduced into the stator winding due to the movement of the rotor) to create a rotating magnetic field with low torque ripple.

In one embodiment, the control panel 13 may have a Field-oriented control Function (FOC). The magnetic field orientation control function can accurately control the size and the direction of the magnetic field, so that the motor 10 has stable torque, low noise, high efficiency and high-speed dynamic response.

In one embodiment, the planetary gear set 12 may include a worm gear 120a, a sun gear 120b, a plurality of

external gears

121a, 121b, 121c, 121d, an external ring gear 122, and a carrier 123, wherein the sun gear 120b and the worm gear 120a are coaxially disposed, the worm gear 120a is engaged with the worm 11, the sun gear 120b and the plurality of

external gears

121a, 121b, 121c, 121d are engaged with each other by being assembled on the carrier 123, and the carrier 123 is used to connect an external transmission shaft (described later). Further, the worm gear 120a and the sun gear 120b serve as power input terminals, the outer ring gear 122 is fixed, and the carrier 123 serves as a power output terminal in operation, which has an effect of reducing the rotation speed. It should be noted that the number of the

external gears

121a, 121b, 121c, and 121d in this embodiment is four, but not limited to this, and other embodiments may have different numbers of external gears.

Referring to fig. 3, fig. 3 is a functional block diagram of a control board according to a third embodiment of the present invention. In one embodiment, the control board 13 may further include a temperature sensing module 130 for sensing the temperature inside the hand tool.

In one embodiment, when the temperature sensed by the temperature sensing module 130 is greater than a predetermined temperature value, the control board 13 sends a first signal to make the motor 10 to rotate down or stop operating. When the hand tool is not operating normally, the internal temperature will rise, and the temperature sensing module 130 can sense the temperature and make the motor 10 to rotate down or stop running before the components are damaged.

In one embodiment, the control board 13 may further include a pressure sensing module 131 for sensing the pressure applied to the hand tool. In detail, when the hand tool is used, the tool piece is pressed against other objects, and the user applies a certain pressure to achieve good cleaning and polishing effects. However, when the hand tool is subjected to excessive pressure, there is a possibility that the components of the hand tool may be damaged.

In one embodiment, when the pressure sensed by the pressure sensing module 131 is greater than a first pressure default value, the control board 13 sends a second signal to make the motor 10 to rotate down or stop operating. In order to avoid the excessive pressure applied to the hand tool, the pressure sensing module 131 can sense the pressure and make the motor 10 to rotate down or stop running before the components are damaged.

In one embodiment, when the pressure sensed by the pressure sensing module 131 is greater than a second pressure default value, the control board 13 sends a third signal to make the motor 10 stop and start repeatedly. As mentioned above, when the tool is started from low speed or stopped, a larger friction force can be obtained than when the tool is continuously operated at high speed, so that the control of the motor 10 by the control board 13 to repeatedly perform the speed reduction, stop and start can make the hand-held tool obtain better cleaning or grinding capability, and the user can trigger the function by applying pressure to the hand-held tool by setting the default value of the second pressure.

In another embodiment, the control board 13 further has a rotation speed compensation function for measuring the rotation speed of the hand tool at any time and performing compensation. In other words, when the pressure is less than the first pressure or the second pressure, or even when the hand tool is in an idle state, the control board 13 will continue to measure and compensate the rotation speed.

In another embodiment, the control board 13 may further include a rotation speed detecting module 132, wherein the rotation speed detecting module 132 is used for feeding back the control signal to control the motor 10 to reach the set rotation speed and to determine the operation state of the motor 10. When the user starts the handheld tool with the power mechanism, the rotation speed detecting module 132 outputs a rotation speed setting signal according to the setting to detect the rotation speed of the motor 10 and obtain a feedback signal. When the feedback signal is not the default feedback signal of the rotation speed detection module 132, it is determined that the current rotation speed is slow. At this time, the control board 13 controls the motor 10 to accelerate, and the rotation speed detecting module 132 continuously captures the real-time feedback signal until the default feedback signal is successfully captured, and then the acceleration is stopped. When the default feedback signal is captured, the rotation speed detection module 132 determines that the motor 10 has reached the default rotation speed. In addition, when the difference between the rotation speed setting signal outputted by the rotation speed detecting module 132 and the extracted feedback signal is too large, it is determined that the motor 10 is locked.

Referring to fig. 2, in an embodiment, the power mechanism may further include

inner housings

14a and 14b, and the worm 11 and the planetary gear set 12 are disposed inside the

inner housings

14a and 14 b. The

inner housings

14a, 14b may protect, isolate, or help secure the worm 11 and components such as the planetary gear set 12. In this embodiment, the

inner housings

14a, 14b are formed by combining two components, and the inner housing 14a is further combined with the outer ring gear 122, but not limited thereto, and in other embodiments, the inner housings may be formed in other manners or combined with other components.

Referring to fig. 4, fig. 4 is an exploded view of a handheld tool according to a fourth embodiment of the present invention. The present invention further provides a handheld tool, which includes

outer housings

40a and 40b, the power mechanism 41, the

control interfaces

42a and 42b, the transmission shaft 43, the tool device 44, and the power module 45.

In one embodiment, the power mechanism 41 is disposed within the

outer housing

40a, 40 b. In this embodiment, the

outer shells

40a and 40b are formed by combining two components, but not limited thereto, the power mechanism 41 is disposed in the accommodating space formed by combining the

outer shells

40a and 40b, and the power mechanism 41 and the

outer shells

40a and 40b can be combined by other fixing members.

In one embodiment, the

control interfaces

42a and 42b are electrically connected to the control board 13 of the power mechanism 41 for inputting control signals. For example, the control interface 42a can be a dial for inputting a control signal of the rotation speed, and the control interface 42b can be a key for inputting a control signal of a switch, but not limited thereto. The

control interfaces

42a, 42b and the control board 13 may be electrically connected by wires.

In one embodiment, the transmission shaft 43 is coupled to the power mechanism 41, and the tool 44 is coupled to the transmission shaft 43. The transmission shaft 43 is used to transmit power provided by the power mechanism 41 to the tool 44 to rotate the tool 44. In this embodiment, the transmission shaft 43 is directly connected to the gear rack 123 of the power mechanism 41, but not limited thereto, and in another embodiment, the transmission shaft 43 may be indirectly connected to the gear rack 123 or be linked with the power mechanism 41 by other methods.

In one embodiment, the tool element 44 may be a brush or a grinding disc, but is not limited thereto and may be replaceable depending on the application.

In one embodiment, the power module 45 is used to supply power for the operation of the power mechanism 41. For example, the power module 45 may be a rechargeable battery or a power cord for connecting with an external power source, but not limited thereto.

In summary, the power mechanism of the present invention includes a motor, a worm, a planetary gear set and a control board, wherein the motor provides power, the worm has functions of converting power direction, reducing speed, etc., the planetary gear set also has a reducing function and excellent transmission efficiency, because of the characteristics of the worm and the planetary gear set, the power mechanism of the present invention has high power conversion efficiency and high torque at low speed output, and controls the operation state of the motor by the control board to provide rotation speed suitable for various states, and further can further use the brushless dc motor and the control board with magnetic field orientation control function to improve torque, power conversion efficiency and more stable rotation speed again. In addition, the control board of the power mechanism can be additionally provided with a temperature sensing module or a pressure sensing module, so that the risk of abnormal states is reduced. The handheld tool with the power mechanism also has the advantages, and the defects in the prior art are fully overcome.

The features and spirit of the present invention will become more apparent to those skilled in the art from the description of the preferred embodiments given above, which are given by way of illustration only, and not by way of limitation, of the principles and functions of the present invention. Thus, any modifications and variations may be made to the above-described embodiments without departing from the spirit of the invention, and the scope of the invention is to be determined by the appended claims.

Claims

1. A power mechanism for use in a hand held tool, the power mechanism comprising:

a motor;

a worm rotated by the motor;

a planetary gear set meshed with the worm; and

and the control board is used for controlling the on-off or running state of the motor.

2. The power mechanism of claim 1, wherein the motor is a brushless dc motor.

3. The power mechanism of claim 2, wherein the control board has a magnetic field orientation control function.

4. The power mechanism according to claim 1, wherein the planetary gear set comprises a worm wheel, a sun gear, a plurality of external gears, an external ring gear and a gear carrier, wherein the sun gear and the worm wheel are coaxially arranged, the worm wheel is engaged with the worm, and wherein the sun gear and the plurality of external gears are engaged by being assembled on the gear carrier, and the gear carrier is used for connecting an external transmission shaft.

5. The power mechanism of claim 1, wherein the control board further comprises a temperature sensing module for sensing a temperature inside the hand tool.

6. The power mechanism as claimed in claim 5, wherein when the temperature sensed by the temperature sensing module is greater than a temperature default value, the control board sends a first signal to turn down or stop the motor.

7. The power mechanism of claim 1, wherein the control board further comprises a pressure sensing module for sensing a pressure applied to the hand tool.

8. The power mechanism as claimed in claim 7, wherein when the pressure sensed by the pressure sensing module is greater than a first pressure default value, the control board sends a second signal to turn down or stop the motor.

9. The power mechanism as claimed in claim 7, wherein when the pressure sensed by the pressure sensing module is greater than a second pressure default value, the control board sends a third signal to enable the motor to stop and start repeatedly.

10. The power mechanism as claimed in claim 1, wherein the control board further comprises a rotation speed detection module for feedback-controlling the motor to reach a default rotation speed and determining the operation status of the motor.

11. The power mechanism of claim 1, further comprising an inner housing, and wherein the worm and the planetary gear set are disposed within the inner housing.

12. A hand tool, comprising:

an outer housing;

the power mechanism as claimed in any one of claims 1 to 11, wherein the power mechanism is disposed within the outer housing;

the control interface is electrically connected with the control panel of the power mechanism and used for inputting a control signal;

the transmission shaft is linked with the power mechanism;

a tool member linked with the transmission shaft; and

and the power supply module is used for supplying power required by the operation of the power mechanism.