TWI599146B - Electric grinding machine with switched reluctance motor - Google Patents

Description

Electric grinder with switched reluctance motor

The present invention relates to an electric grinder, and more particularly to an electric grinder having a switched reluctance motor.

According to the electric grinder, the electric grinder is a polishing hand-held machine that uses electric power as a driving source, and the electrician can use the electric grinder to polish or grind the surface of objects such as metal or wood.

For example, the M428013 patent of the Republic of China Patent Publication discloses an electric grinder comprising a housing, a brushless motor, a circuit board, a push button switch, and a variable resistor. The housing has a first end and a second end, the first end having a head, the second end having a grip portion, the grip portion having a shank extending toward the first end. The brushless motor is mounted in the head. The circuit board is disposed in the grip portion and electrically connected to the brushless motor, and the circuit board has a control panel formed on a surface of the grip portion. The push button switch has a pressing button, a limiting seat and an elastic member, and the pressing button is disposed on the grip portion, the pressing button has a connecting portion extending toward the inside of the housing, the limiting seat is fixed to the button The circuit board, the elastic member is disposed between the pressing button and the limiting seat. The variable resistor is mounted on the circuit board, and one end of the variable resistor is formed with a regulating rod that is coupled to the connecting portion. Further, when the electric grinder is actually used, the user can interlock the adjusting rod by the pressing button, so that the variable resistor changes with the position of the adjusting rod to generate a resistance change, thereby outputting the circuit board. Different electric power is applied to the brushless motor to achieve the function of controlling the rotational speed.

However, it can be found from the technical content of the above patent and the composition of the general electric grinder that since the brushless motor is mostly a brushless DC motor (BLDC motor), the electric grinder is It is quite easy to operate due to the Lost of Phase, and the Cogging Torque of the DC brushless motor can also make the electric grinder unsuitable for frequent start and stop and positive and negative phases. The health of the conversion.

Accordingly, it can be clearly seen from the above that how to design an electric grinder that can be applied to operating conditions such as under-phase, frequent start-stop, and forward-negative conversion has become a problem to be solved.

The main object of the present invention is to solve the problem that the conventional implementation structure cannot be applied to operating conditions such as owing phase, frequent start and stop, and forward and reverse phase conversion.

To achieve the above object, the present invention provides an electric grinder having a switched reluctance motor including a body, a transmission assembly, a grinding wheel, and a dustproof assembly. The body has a first shell and a second shell. The first shell defines a chamber. The second shell is disposed opposite the first shell and has an accommodating space communicating with the chamber. The transmission assembly has a switched reluctance motor disposed in the chamber, a pair of hollow portions disposed in the accommodating space and electrically connected to the switched reluctance motor to output a control of the switched reluctance motor a driving module of the signal, a driving shaft connected to the switched reluctance motor, and a mounting seat mounted on an end of the driving shaft away from the switching reluctance motor, the mounting base having an assembly connecting the transmission shaft and A flow guiding portion is formed by forming a step difference with the assembly portion and deviating from the axis of the transmission shaft to generate a heat dissipation cyclone when the transmission shaft is rotated. The grinding wheel is mounted on the assembly portion and rotates with the transmission shaft, and the dustproof assembly comprises a dust cover mounted on the first casing and forming a gap between the grinding wheel and a dust cover and a connection The second casing is arranged to receive a dust exhausting duct for attracting airflow from an air extracting device, and the dust exhausting duct has a pair of openings that should be accommodated in the receiving space to dissipate heat to the driving module by the suction airflow.

In one embodiment, the driving module has a microcontroller for generating the control signal and is electrically connected between the microcontroller and the switched reluctance motor to transmit the control signal to the switching mode. Reluctance motor drive.

In one embodiment, the switched reluctance motor is a three-phase switched reluctance motor, and the driver is a three-phase half-bridge driver or a three-phase full-bridge driver. Further, the switched reluctance motor has an outer stator and an inner rotor, and the transmission assembly has a plurality of components disposed on the first casing and facing the inner rotor to monitor the inner rotor position to output a monitoring to the driving module. The photoelectric switch of the signal. The photoelectric switches are centered on the drive shaft and are spaced apart from each other by a step angle. Specifically, the driving module has a variable angle control mechanism and a voltage pulse width modulation control mechanism, and the driving module determines the variable angle control mechanism or the voltage according to each of the monitoring signals transmitted by the photoelectric switches. The pulse width modulation control mechanism generates the control signal.

In one embodiment, the first housing has at least one air inlet opening that communicates with the chamber to allow external air to enter the chamber. Further, the transmission assembly has a resilient button disposed on the first casing to be pressed to trigger the driving module, and a pressing plate pivotally connected to the second casing and extending above the elastic button to press and press the elastic button .

Through the above embodiments of the present invention, the following features are compared with the conventional ones:

1. The electric grinder of the present invention uses the switched reluctance motor as a driving source, so that the electric grinder can be applied to the phasing frequent start and stop by the characteristics of the switched reluctance motor during operation. And other operating conditions such as forward and reverse conversion.

2. The electric grinder of the present invention can discharge the thermal energy in the chamber through the flow guiding portion during use and transmit the thermal energy of the driving module together with the dust through the suction airflow, thereby effectively switching the heat. The reluctance motor dissipates heat significantly.

The technical content of the present invention will now be described as follows:

Referring to FIG. 1 and FIG. 2, the present invention provides an electric grinder having a switched reluctance motor, comprising a body 1, a transmission assembly 2, a grinding wheel 3, and a dustproof assembly 4. The body 1 has a first housing 11 and a second housing 12 . The first housing 11 defines a cavity 110 . The second housing 12 has an accommodating space 120 . The accommodating space 120 and the chamber 110 . Connected to each other. The transmission assembly 2 has a switched reluctance motor 21, a drive module 22, a drive shaft 23, and a mounting base 24. The switched reluctance motor 21 is disposed in the chamber 110 and has an outer stator 211 and an inner rotor 212. The outer stator 211 and the inner rotor 212 are stacked by electromagnetic steel sheets (eg, silicon steel sheets). The driving module 22 is disposed in the accommodating space 120, and the switching reluctance motor 21 and the driving module 22 are electrically connected to each other. In an embodiment, the chamber 110 of the first casing 11 is cylindrically disposed for the switched reluctance motor 21, and the first casing 11 has at least one communication chamber 110 for external gas. The switched reluctance motor 21 rotates to enter the intake hole 111 of the chamber 110. Further, the first casing 11 is composed of a main casing 112 and a sub-housing 113 installed in the main casing 112. The chamber 110 is formed inside the main casing 112, and the air inlet 111 is disposed. In the sub-shell 113. In addition, the driving module 22 has a microcontroller 221 and a driver 222 electrically connected between the microcontroller 221 and the switched reluctance motor 21, and the accommodating space 120 of the second casing 12 It is in the form of a strip for the circuit board (ie, the drive module 22). Specifically, the switched reluctance motor 21 is a 3-Phase Switched Reluctance Motor, and the driver 222 is capable of driving the three-phase switched reluctance motor (ie, the switched reluctance motor) Motor 21) Actuated 3-Phase Half Bridge Driver or 3-Phase Full Bridge Driver. In one embodiment, the transmission assembly 2 has a resilient button 25 disposed on the first housing 11 to conduct the switched reluctance motor 21 and the driving module 22, and a pivotal connection to the second housing 12 Extending to the pressure plate 26 above the elastic button 25, the elastic button 25 is elastically reset to a predetermined position when not pressed, and the pressure plate 26 can be pressed to press the elastic button 25 in conjunction. On the other hand, the transmission shaft 23 is connected to the switched reluctance motor 21 and extends to the outside of the first housing 11. The mounting base 24 is assembled at one end of the transmission shaft 23 away from the switching reluctance motor 21. . More specifically, the mounting base 24 has an assembly portion 241 and a flow guiding portion 242. The assembly portion 241 is coupled to the transmission shaft 23 and offset from the axis of the transmission shaft 23. The flow guiding portion 242 is coupled to the assembly portion. The 241 is coupled and extends in a direction away from the axis of the drive shaft 23. In one embodiment, the flow guiding portion 242 is a convex plate (as shown in FIG. 2). In other embodiments, the flow guiding portion 242 is at least one fan blade. Finally, the grinding wheel 3 is mounted on the assembly portion 241. The dustproof assembly 4 has a dust cover 41 and a dust exhausting duct 42 mounted between the first casing 11 and the grinding wheel 3. A gap (as shown in FIG. 4) is formed. The dust exhaust duct 42 is connected to the dust cover 41, and the dust exhaust duct 42 has an opening 420 corresponding to the accommodating space 120 (as shown in FIG. 4).

Referring to FIG. 1 to FIG. 7 , in the actual use of the electric grinder of the present invention, the driving module 22 is connected to an electric device (not shown) for the driving module 22 to be obtained by the electric device. The electricity required to operate. Then, the user can press the elastic button 25 through the pressing plate 26 to turn on the driving module 22 to the switched reluctance motor 21, so that the microcontroller 221 can transmit a control signal to the driver 222. The inner rotor 212 of the switched reluctance motor 21 drives the drive shaft 23 to rotate, and the grinding wheel 3 can be rotated by the drive shaft 23 to an object (not shown). The surface is ground. Wherein, the electric grinder of the present invention uses the switched reluctance motor 21 as a driving source, so that the electric grinder can pass through the characteristics of the switched reluctance motor 21 during operation. In the case of Lost of Phase, it works well, and it can be applied to operating conditions such as frequent start and stop and forward and reverse conversion.

The present invention further describes the actuation relationship between the switched reluctance motor 21 and the drive module 22. In detail, the driving module 22 has a variable angle control mechanism (ASR) and a voltage pulse width modulation control mechanism (PWM), and the driving module 22 according to the speed of the switched reluctance motor 21 Adjusting the output ratio between the variable angle control mechanism and the voltage pulse width modulation control mechanism. If the speed of the switched reluctance motor 21 is slower, the output ratio of the variable angle control mechanism will increase; if the speed of the switched reluctance motor 21 is faster, the output ratio of the voltage pulse width modulation control mechanism Then it increases. In an embodiment, as shown in FIG. 7 , the inner rotor 212 has a rotation direction relative to the outer stator 211 after the power is activated, and the outer stator 211 has a plurality of first ends extending toward the inner rotor 212 . a magnetic conductive portion 213 having a plurality of second magnetic conductive portions 214 extending in the direction of the outer stator 211 and a plurality of magnetic conductive convex portions 215 extending integrally from each of the second magnetic conductive portions 214 toward the rotational direction . When the outer stator 211 is magnetically guided, the first magnetic conductive portions 214 are respectively attracted by the first magnetic conductive portions 213 to rotate the inner rotor 212. The present invention has the design of the magnetic conductive protrusions 215, so that each of the second magnetic conductive portions 214 can be shortened by the associated magnetic conductive protrusions 215 and the first one of the first magnetic conductive portions 213. The distance between the second magnetic conductive portion 214 and the second magnetic conductive portion 213 can be pre-triggered to the first magnetic conductive portion 213 to attract the second magnetic conductive portion 213. The second magnetic conductive portion 214 is configured such that the switched reluctance motor 21 can accelerate the inner rotor 212 by the actuating relationship between the first magnetic conductive portions 213 and the magnetic conductive convex portions 215. The speed of rotation.

Specifically, in order to enable the driving module 22 to detect the rotational speed of the switched reluctance motor 21, in an embodiment, the transmission assembly 2 has a plurality of components disposed on the first casing 11 and facing the inner rotor. The photoelectric switch 27 of the 212, the photoelectric switch 27 can block the position and the speed of the inner rotor 212 through the position and frequency of the inner rotor 212, and then transmit a monitoring signal according to the position and speed of the inner rotor 212 to The driving module 22 enables the driving module 22 to determine the variable angle control mechanism and the output ratio of the voltage pulse width modulation control mechanism through the monitoring signal of each of the photoelectric switches 27. In one embodiment, the photoelectric switches 27 are centered on the drive shaft 23 and are spaced apart from each other by a step angle, that is, between the photoelectric switch 27 and the drive shaft 23 An angle is formed (eg, thirty degrees). In addition, the microcontroller 221 can also detect the switch through the driver 222 in addition to providing the monitoring signal through the photoelectric switches 27 as a reference for determining the position and speed of the inner rotor 212. The magnitude of the current of the reluctance motor 21, and when the current value of the switched reluctance motor 21 exceeds the rated current value, the input current of the switched reluctance motor 21 is cut off by the driver 222 (ie: overcurrent protection [Over Current] Protection]) to prevent the switched reluctance motor 21 from being burnt due to excessive current. Moreover, the microcontroller 221 can also adjust the input current of the driver 222 to the switched reluctance motor 21 according to the current magnitude of the switched reluctance motor 21, and thus, when the switched reluctance motor When the grinding wheel 3 is blocked (for example, pressing against the surface of an object) and the current changes, the microcontroller 221 can adjust the input of the switched reluctance motor 21 through the feedback of the driver 222. The current is such that the switched reluctance motor 21 can maintain a certain rotational speed when the grinding wheel 3 is blocked.

On the other hand, it is worth noting that during the execution of the grinding operation by the electric grinder, the flow guiding portion 242 is rotated by the driving shaft 23 to generate a heat dissipating cyclone, so that the switching reluctance motor 21 is The heat generated by the swirling is discharged to the outside of the chamber 110 in accordance with the heat-dissipating cyclone. In addition, since the dusting duct 42 is connected to an air extracting device (not shown) when the electric grinder is in use, the driving module 22 is disposed relative to the opening 420, and therefore, when When a suction airflow generated by the air exhausting device flows through the dust exhausting duct 42, the airflow is sucked out by the dust exhausting duct 42 together with the waste heat and dust generated by the driving module 22. Accordingly, the electric grinder of the present invention can discharge the heat energy in the chamber 110 through the flow guiding portion 242 during use, and bring the heat energy of the driving module 22 together with the dust through the suction airflow. Therefore, the electric grinder can greatly dissipate the switching reluctance motor 21 and the drive module 22.

In summary, the present invention discloses an electric grinder having a switched reluctance motor, the electric grinder comprising a body, a transmission assembly, a grinding wheel and a dustproof assembly, the body having a first shell and a first a two-shell, the transmission assembly has a switched reluctance motor disposed on the first casing, a drive module disposed on the second casing, a drive shaft coupled to the switched reluctance motor, and a transmission disposed on the transmission a mounting seat for the shaft, the mounting base having an assembly portion for mounting the grinding wheel, the dustproof assembly having a dust cover disposed on the first housing. Wherein, the electric grinder is driven by the switched reluctance motor, so that the electric grinder can be applied to operating conditions such as owing phase, frequent start and stop, and forward and reverse phase conversion.

The present invention has been described in detail above, but the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Variations and modifications are still within the scope of the patents of the present invention.

1‧‧‧ body

11‧‧‧ first shell

110‧‧‧ chamber

111‧‧‧Air intake

112‧‧‧ main shell

113‧‧‧Subshell

12‧‧‧ second shell

120‧‧‧ accommodating space

2‧‧‧Transmission components

21‧‧‧Switched Reluctance Motor

211‧‧‧Outer stator

212‧‧‧ inner rotor

213‧‧‧First magnetic guide

214‧‧‧Second magnetic guide

215‧‧‧Magnetic convex

22‧‧‧Drive Module

221‧‧‧Microcontroller

222‧‧‧ drive

23‧‧‧ drive shaft

24‧‧‧Assemble

241‧‧‧Assembly Department

242‧‧‧Drainage Department

25‧‧‧Flexible button

26‧‧‧Press

27‧‧‧ photoelectric switch

3‧‧‧ grinding wheel

4‧‧‧Dustproof components

41‧‧‧ dust cover

42‧‧‧Dust exhaust duct

420‧‧‧ openings

Figure 1 is a perspective view of the present invention. Figure 2 is an exploded perspective view of the present invention. Figure 3 is an exploded perspective view of another perspective of the present invention. Figure 4 is a side cross-sectional view of the present invention. FIG. 5 is a circuit diagram of a driving module of the present invention. Figure 6 is a top plan view of the present invention. Figure 7 is a schematic cross-sectional view of the present invention.

11‧‧‧ first shell

111‧‧‧Air intake

112‧‧‧ main shell

113‧‧‧Subshell

12‧‧‧ second shell

2‧‧‧Transmission components

21‧‧‧Switched Reluctance Motor

22‧‧‧Drive Module

23‧‧‧ drive shaft

24‧‧‧Assemble

242‧‧‧Drainage Department

25‧‧‧Flexible button

26‧‧‧Press

3‧‧‧ grinding wheel

4‧‧‧Dustproof components

41‧‧‧ dust cover

42‧‧‧Dust exhaust duct

420‧‧‧ openings

Claims (8)

An electric grinder having a switched reluctance motor, comprising: a body having a first shell and a second shell, the first shell forming a chamber therein, the second shell being disposed corresponding to the first shell and Having a accommodating space in communication with the chamber; a transmission assembly having a switched reluctance motor disposed in the chamber, and a magnetic reluctance motor disposed in the accommodating space and electrically connected to the switching reluctance motor The switching reluctance motor outputs a control signal driving module, a driving shaft connected to the switching reluctance motor, and a mounting seat mounted on the driving shaft away from the end of the switching reluctance motor, the mounting base has An assembly portion connecting the transmission shaft and a flow guiding portion formed by forming a step difference from the assembly portion and offset from the shaft center of the transmission shaft to generate a heat dissipation cyclone when the transmission shaft is rotated; and a grinding wheel and a dustproof assembly The grinding wheel is mounted on the assembly portion and rotates with the transmission shaft. The dustproof assembly comprises a dust cover mounted on the first casing and forming a gap between the grinding wheel and a dust cover and a dust cover. Since the two shells is provided a dust-exhaust ventilation means for receiving a suction air duct, which has a pair of dust discharge conduit accommodating space should be opened and the opening of the suction air for cooling the driving module. An electric grinder having a switched reluctance motor according to claim 1, wherein the driving module has a microcontroller for generating the control signal, and is electrically connected to the microcontroller and the switching magnetic The control signal is transmitted between the motors to the driver of the switched reluctance motor. An electric grinder having a switched reluctance motor according to claim 2, wherein the switched reluctance motor is a three-phase switched reluctance motor, and the driver is a three-phase half-bridge driver or a three-phase full-bridge driver. An electric grinder having a switched reluctance motor according to claim 2, wherein the switched reluctance motor has an outer stator and an inner rotor, and the transmission assembly has a plurality of the first shell and faces the inner casing The rotor outputs a photoelectric switch for monitoring signals to the driving module by monitoring the position of the inner rotor. An electric grinder having a switched reluctance motor according to claim 4, wherein the photoelectric switches are centered on the drive shaft and are spaced apart from each other by a step angle. An electric grinder having a switched reluctance motor according to claim 4 or 5, wherein the driving module has a variable angle control mechanism and a voltage pulse width modulation control mechanism, and the driving module is based on the photoelectric switches Each of the transmitted monitoring signals determines that the control signal is generated by the variable angle control mechanism or the voltage pulse width modulation control mechanism. An electric grinder having a switched reluctance motor according to claim 1, 2, 3, 4 or 5, wherein the first casing has at least one intake air that communicates with the chamber to allow external gas to enter the chamber hole. An electric grinder having a switched reluctance motor according to claim 7, wherein the transmission assembly has a resilient button disposed on the first casing to be pressed to trigger the driving module, and a pivoting connection to the second The shell extends over the elastic button to interlock the platen of the elastic button.