Electric tool

Abstract

The invention provides an electric tool. The electric tool comprises a machine shell, a controller located in the machine shell, a motor and a temperature collecting module. Wherein the Hall plate is arranged at the end part of the motor, the temperature acquisition module is close to the Hall plate, and the temperature acquisition module is used for detecting the first temperature of the motor. And the controller is electrically connected to the motor and the temperature acquisition module, and the controller is configured to obtain the first temperature output by the temperature acquisition module and detect the load current of the motor, so as to determine the second temperature of the motor according to the first temperature and the load current of the motor, and control the working state of the motor based on the load current and the second temperature. According to the electric tool provided by the invention, the demagnetization phenomenon when the temperature of the motor is too high can be avoided, and the reliability of the motor is improved.

Description

Technical Field

[0001] The present application relates to the technical field of electric tools, and in particular to an electric tool. Background Art

[0002] In existing power tools such as polishing machines, when the machine is overloaded, the torque and loss of the motor will increase accordingly, which will eventually cause the motor temperature to be too high. If the motor continues to work at this time, it will cause demagnetization of the motor, which will in turn affect the magnetic field distribution inside the motor. Long-term high-temperature operation will accelerate the aging of the motor, shorten the service life of the motor, and even cause the entire machine to fail to start. Summary of the invention

[0003] In view of the above, the present application provides an electric tool for solving the problem of motor demagnetization caused by excessive motor temperature.

[0004] The first aspect of the present application provides an electric tool, comprising: a housing, a controller located in the housing, a motor, and a temperature acquisition module. The Hall plate is arranged at the end of the motor, the temperature acquisition module is adjacent to the Hall plate, and the temperature acquisition module is used to detect a first temperature of the motor. The controller is electrically connected to the motor and the temperature acquisition module, and the controller is configured to obtain a first temperature output by the temperature acquisition module and detect a load current of the motor, determine a second temperature of the motor according to the first temperature and the load current of the motor, and control the working state of the motor based on the load current and the second temperature.

[0005] By adopting the embodiment of the present application, the motor and the temperature acquisition module are electrically connected to the controller, and the temperature acquisition module is set on the Hall plate at the end of the motor, so that the first temperature output by the temperature acquisition module can be obtained through the controller, and the load current of the motor can be detected through the controller, and then the second temperature of the motor can be determined according to the first temperature and the load current of the motor, and the working state of the motor can be controlled based on the load current and the second temperature to avoid demagnetization when the temperature of the motor is too high, thereby improving the reliability of the motor.

[0006] According to some embodiments of the present application, the temperature acquisition module includes a circuit board and a temperature sensing element mounted on the circuit board, the Hall plate includes a soldering pad, and the circuit board is soldered to the soldering pad of the Hall plate.

[0007] According to some embodiments of the present application, a through hole is provided on the Hall plate for dissipating heat from the motor.

[0008] According to some embodiments of the present application, the circuit board is arranged on the surface of the Hall plate facing away from the motor and the circuit board at least partially covers the through hole, or the circuit board is located on the surface of the Hall plate facing the motor; wherein the temperature sensing element is arranged on the surface of the circuit board facing the motor.

[0009] According to some embodiments of the present application, the temperature sensing element is arranged on the side of the circuit board and the Hall plate where there is no pad for welding. The temperature sensing element is a pin-type thermistor. The temperature sensing element is led out through a connecting wire and is arranged near the motor.

[0010] According to some embodiments of the present application, the controller is configured to control the motor to stop working when the second temperature is greater than the third temperature.

[0011] According to some embodiments of the present application, the controller is configured to control the operation of the motor according to a first temperature when the load current is less than or equal to a first preset current.

[0012] According to some embodiments of the present application, the controller is configured to control the motor to stop when the first temperature is greater than the fourth temperature.

[0013] According to some embodiments of the present application, the controller is configured to control the working state of the motor according to the second temperature when the load current is greater than a first preset current and less than or equal to a second preset current.

[0014] According to some embodiments of the present application, the formula for calculating the second temperature is:

[0015] T2=T1+k×(I2-I1)+T3

[0016] Among them, T1 is the first temperature, T2 is the second temperature, T3 is the preset temperature, k is the setting coefficient, I1 is the first preset current, and I2 is the load current. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a side view of an electric tool provided in one embodiment of the present application.

[0018] Figure 2 It is another structural schematic diagram of the electric tool provided in one embodiment of the present application.

[0019] Figure 3 It is a schematic diagram of the structure of a Hall plate and a temperature acquisition module provided in one embodiment of the present application.

[0020] Figure 4 It is a schematic diagram of the structure of a Hall plate and a temperature acquisition module provided in another embodiment of the present application.

[0021] Figure 5 This is a circuit diagram of an electric tool provided in one embodiment of the present application.

[0022] Figure 6 This is a circuit diagram of an electric tool provided in another embodiment of the present application.

[0023] Figure 7This is a circuit diagram of an electric tool provided in another embodiment of the present application.

[0024] Main component symbols

[0025] Controller 10

[0026] Motor 20

[0027] Temperature acquisition module 30

[0028] Control panel 40

[0029] Hall plate 50

[0030] Circuit board 60

[0031] Terminal block SW

[0032] Through holes 501, 502, 503

[0033] First connection 50

[0034] Second connection 60

[0035] Testing equipment11

[0036] Temperature sensing element Rntc

[0037] The first resistor R48

[0038] The second resistor R50

[0039] The third resistor R49

[0040] The fourth resistor R51

[0041] The first capacitor C24

[0042] The second capacitor C25

[0043] Pull-up power supply VCC DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0045] The term "and / or" in this application is a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The symbol " / " in this article indicates that the associated objects are in an or relationship, for example, A / B means A or B.

[0046] In the present application, the term "plurality" refers to two or more. In addition, it should be understood that in the description of the present application, the terms "first", "second", etc. are only used for the purpose of distinguishing descriptions, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying an order.

[0047] In the description of the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0048] In existing power tools such as polishing machines, when the machine is overloaded, the torque and loss of the motor will increase accordingly, which will eventually cause the motor temperature to be too high. If the motor continues to work at this time, it will cause demagnetization of the motor, which will in turn affect the magnetic field distribution inside the motor. Long-term high-temperature operation will accelerate the aging of the motor, shorten the service life of the motor, and even cause the entire machine to fail to start.

[0049] To this end, an embodiment of the present application provides an electric tool for solving the problem of motor demagnetization caused by excessive motor temperature.

[0050] See also Figure 1 and Figure 2 , Figure 1 and Figure 2 It is a structural schematic diagram of an electric tool provided by an embodiment of the present application.

[0051] like Figure 1 and Figure 2 As shown, the electric tool includes a housing (not shown in the figure), a controller (not shown in the figure) located in the housing, a motor 20 and a temperature acquisition module 30. The temperature acquisition module 30 is adjacent to the Hall plate 50. Optionally, the temperature acquisition module 30 is arranged on the Hall plate 50 of the motor 20. The Hall plate 50 is arranged at the end of the motor 20. Specifically, the Hall plate 50 can be arranged at the end of the motor stator.

[0052] The controller is used to: obtain the first temperature output by the temperature acquisition module 30 and detect the load current of the motor 20, then determine the second temperature of the motor 20 according to the first temperature and the load current of the motor 20, and control the working state of the motor 20 based on the load current and the second temperature.

[0053] In an optional implementation, the controller can obtain the current value collected by the collection device once every 500 ms, add the collected current values ​​every 10s and divide them by the total number of current values ​​within 10s to obtain the average of each current value, and use the average as the load current of the motor 20, so that the controller 10 can determine the second temperature of the motor 20 based on the first temperature and the load current of the motor 20, and control the working state of the motor 20 based on the load current and the second temperature, thereby further improving the control accuracy of the controller 10.

[0054] Optionally, the formula for calculating the second temperature is T2=T1+k×(I2-I1)+T3. Wherein, T1 is the first temperature, i.e., the ambient temperature near the motor 20 acquired by the temperature acquisition module 30; T2 is the second temperature, i.e., the actual temperature of the motor 20; T3 is the preset temperature, i.e., the difference between the actual temperature of the motor 20 and the ambient temperature near the motor 20 under the first preset current; k is the setting coefficient; I1 is the first preset current; I2 is the load current, i.e., the current working current of the motor 20. Specifically, when T2 is 100°C, I1 is 15A, and T3 is 40°C, k can be -1. Optionally, the values ​​of I1, k, I2 and T3 can also be determined according to the actual application environment, which is not specifically limited here. By compensating for the first temperature, the accuracy of the temperature data is improved.

[0055] In actual applications, since there is a certain difference between the first temperature collected by the temperature acquisition module 30 and the actual temperature of the motor 20, and the difference will change with the load current of the motor 20, the electric tool provided in the present application determines the second temperature of the motor 20 according to the first temperature and the load current of the motor 20 through a controller, so as to control the working state of the motor 20 based on the load current and the second temperature, thereby avoiding demagnetization when the temperature of the motor 20 is too high, and improving the safety and reliability of the motor 20.

[0056] In addition, the temperature acquisition module 30 may also be disposed at a location that is easy to install, such as a housing or a motor wall near the Hall plate 50 .

[0057] See also Figure 3 and Figure 4In an optional implementation, the temperature acquisition module 30 includes a circuit board 60 and a temperature sensing element Rntc mounted on the circuit board 60, and the Hall plate 50 includes a pad. Optionally, the temperature sensing element Rntc shown can be a pin-type thermistor or a patch-type thermistor. Specifically, Figure 3 As shown, the temperature sensing element Rntc can be a thermistor, but is not limited thereto in practical applications. It depends on the specific application environment and is within the protection scope of this application.

[0058] In practical applications, the Hall plate 50 is provided with through holes for heat dissipation of the motor 20, such as Figure 3 The through hole 501, through hole 502 and through hole 503 are shown in FIG. The circuit board 60 is disposed on the surface of the Hall plate 50 facing away from the motor 20 and the circuit board 60 at least partially covers the through hole. The temperature sensing element Rntc is disposed on the surface of the circuit board 60 facing the motor 20. Figure 3 Taking the through hole 501 as an example, the temperature sensing element Rntc is arranged on the surface of the circuit board 60 close to the through hole 501 to collect the first temperature through the through hole 501, and the motor 20 can dissipate heat through the through hole 501, the through hole 502 and the through hole 503, so that the controller can accurately collect the first temperature in the motor 20.

[0059] Optionally, the circuit board 60 may be located on the surface of the Hall plate 50 facing the motor 20 and the temperature sensing element Rntc may be disposed on the surface of the circuit board 60 facing the motor 20 , and the temperature sensing element Rntc may be a surface-mount thermistor element.

[0060] In an optional implementation, the circuit board 60 is soldered to the Hall plate 50 via a solder pad, and the temperature sensing element Rntc is disposed on a side of the circuit board 60 and the Hall plate 50 where no solder pad is soldered, and the temperature sensing element Rntc is led out via wiring and disposed near the motor 20, and the temperature sensing element Rntc is connected to a controller via wiring, and the temperature sensing element Rntc can be a pin-type thermistor.

[0061] In practical applications, such as Figure 5As shown, the controller 10 can be arranged on the control board 40, the first end of the controller 10 is connected to the first end of the terminal row SW through the first resistor R48, and the second resistor R50 and one end of the first capacitor C24 are connected to the first end of the controller 10, the other end of the second resistor R50 is connected to the pull-up power supply VCC, and the other end of the first capacitor C24 is grounded, the second end of the controller 10 is connected to the second end of the terminal row SW through the third resistor R49, and the fourth resistor R51 and one end of the second capacitor C25 are connected to the first end of the controller 10, the other end of the third resistor R51 is connected to the pull-up power supply VCC, and the other end of the second capacitor C24 is grounded. Optionally, the pull-up power supply VCC can be a 5V power supply, which is not limited to this in actual applications, depending on its specific application environment.

[0062] See also Figure 6 When the first end of the terminal block SW is connected to the first end of the detection device 11 through the first wiring 50, and the second end of the terminal block SW is connected to the second end of the detection device 11 through the second wiring 60, the controller 10 can detect the rotation direction of the motor 20 through the first and second ends of the terminal block SW and the detection device 11, and limit the current value input to the controller 10 through the first resistor R48 and the third resistor R49 to prevent the current of the detection signal from being too large to damage the controller 10.

[0063] When the electric tool is a polishing machine, the motor 20 only needs to rotate in one direction, so the controller 10 does not need to detect the rotation direction of the motor 20 through the first end and the second end of the terminal block SW. Figure 7 In this embodiment, the first end of the terminal block SW is connected to one end of the temperature sensing element Rntc through the first wiring 50, and the second end of the terminal block SW is connected to the other end of the temperature sensing element Rntc through the second wiring 60, and the second resistor R50 and the fourth resistor R51 can be 10kΩ resistors, and the first capacitor C24 can be 0.1μF capacitor. Optionally, 0Ω resistors can also be used as the first resistor 48 and the third resistor R49, and 0μF capacitors can be used as the second capacitor C25, so that one end of the temperature sensing element Rntc can output the first temperature to the controller 10 through the first end of the terminal block and the first resistor 48, and the other end of the temperature sensing element Rntc can be grounded through the second end of the terminal block SW, the third resistor R49 and the second capacitor C25 in sequence, so that the control board 40 in the existing electric tool can be connected to the temperature sensing element Rntc without rewiring to obtain the first temperature collected by the temperature sensing element Rntc.

[0064] In an optional implementation, the controller 10 is used to control the motor 20 to operate when the second temperature is less than or equal to the third temperature, and to control the motor 20 to stop operating when the second temperature is greater than the third temperature, so as to avoid demagnetization when the temperature of the motor 20 is too high, thereby improving the safety and reliability of the motor 20.

[0065] Specifically, the temperature sensing element Rntc outputs a first temperature to the controller 10, and the controller 10 determines a second temperature of the motor 20 based on the first temperature and the load current of the motor 20, and when the second temperature is less than or equal to the third temperature, the controller 10 controls the motor 20 to work, and when the second temperature is greater than the third temperature, the controller 10 controls the motor 20 to stop working, so as to avoid demagnetization when the temperature of the motor 20 is too high, thereby improving the safety and reliability of the motor 20.

[0066] Optionally, the third temperature is a temperature that can cause demagnetization of the motor 20, and may be specifically 100 degrees Celsius. It is not limited thereto in practical applications and may depend on the specific application environment, all of which are within the protection scope of this application.

[0067] In actual applications, when the heat dissipation capacity of the motor 20 is strong enough and the load current is less than the first preset current, the temperature of the motor 20 will not exceed the third temperature, wherein the controller 10 is used to control the motor 20 to operate according to the first temperature when the load current is less than or equal to the first preset current.

[0068] Specifically, when the first temperature is less than the fourth temperature, the temperature of the motor 20 and the ambient temperature near the motor 20 are both within the preset normal working range of the motor 20, and the controller 10 can control the motor 20 to work. When the first temperature is greater than or equal to the fourth temperature, it means that at least one of the temperature of the motor 20 and the ambient temperature near the motor 20 is not within the preset normal working range of the motor 20, and the controller 10 can control the motor 20 to stop working, or when the first temperature is greater than or equal to the fourth temperature, the controller 10 can control the motor 20 to reduce the working efficiency to reduce the heat generated by the motor 20, thereby avoiding the demagnetization phenomenon caused by the excessive temperature of the motor 20, affecting the working state of the motor 20, and improving the safety and reliability of the motor 20.

[0069] Optionally, the fourth temperature is lower than the third temperature. The specific value of the fourth temperature is not specifically limited here and may be determined according to the actual application environment, and is within the protection scope of the present application.

[0070] In an optional implementation, the controller 10 is used to control the working state of the motor 20 according to the second temperature when the load current is greater than the first preset current and less than or equal to the second preset current. Specifically, when the load current is greater than the first preset current and less than or equal to the second preset current, the controller 10 obtains the first temperature output by the temperature sensing element Rntc and detects the load current of the motor 20, and then determines the second temperature of the motor 20 according to the first temperature and the load current of the motor 20. When the second temperature is less than or equal to the third temperature, the controller 10 controls the motor 20 to work, and when the second temperature is greater than the third temperature, the controller 10 controls the motor 20 to stop working, so as to avoid demagnetization when the temperature of the motor 20 is too high, thereby improving the safety and reliability of the motor 20.

[0071] Optionally, when the load current is greater than the second preset current, the controller 10 controls the motor 20 to stop. Optionally, the first preset current may be 15A, and the second preset current may be 40A. The actual application is not limited thereto, and it depends on the specific application environment.

[0072] Specifically, when the load current of the motor 20 is greater than the second preset current, the motor 20 may be in an overloaded operating state. Long-term overload operation will cause the motor 20 to overheat. Therefore, the controller 10 can control the motor 20 to shut down when the load current of the motor 20 is greater than the second preset current to avoid demagnetization when the motor 20 is overloaded and the temperature is too high.

[0073] In actual applications, when a short circuit occurs in the internal or external circuit of the motor 20, the load current of the motor 20 will surge. Continuous operation with a large current will cause the temperature of the motor 20 to be too high, which will in turn cause the motor 20 to demagnetize. Therefore, the controller 10 can control the motor 20 to shut down when the load current of the motor 20 is greater than the second preset current to avoid demagnetization of the motor 20.

[0074] Specifically, when the second temperature is 100 degrees Celsius and the first preset current is 15A, the first temperature and preset temperature corresponding to different load currents can be as shown in Table 1 below. The actual application is not limited to this and depends on the specific application environment.

[0075] Table 1

[0076]

[0077]

[0078] The electric tool provided in the present application electrically connects the motor 20 and the temperature acquisition module 30 to the controller 10, and the temperature acquisition module 30 is set on the Hall plate 50 at the end of the motor 20, so as to obtain the first temperature output by the temperature acquisition module 30 through the controller 10, and detect the load current of the motor 20 through the controller 10, and then determine the second temperature of the motor 20 according to the first temperature and the load current of the motor 20, and control the working state of the motor 20 based on the load current and the second temperature. When the load current is greater than the second preset current, the controller 10 controls the motor 20 to stop. When the load current is greater than the first preset current and less than or equal to the second preset current, the working state of the motor 20 is controlled according to the second temperature. Specifically, when the second temperature is less than or equal to the third temperature, the controller 10 controls the motor 20 to work, and when the second temperature is greater than the third temperature, the controller 10 controls the motor 20 to stop working, so as to avoid demagnetization when the temperature of the motor 20 is too high, thereby improving the safety and reliability of the motor 20.

[0079] It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and that the present application can be implemented in other specific forms without departing from the spirit or basic features of the present application. Therefore, no matter from which point of view, the above embodiments of the present application should be regarded as exemplary and non-restrictive, and the scope of the present application is defined by the attached claims rather than the above description, and therefore it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present application.

Claims

1. An electric tool, characterized in that: include: A housing, a controller located inside the housing, a motor and a temperature acquisition module; The Hall plate is arranged at the end of the motor, the temperature acquisition module is adjacent to the Hall plate, and the temperature acquisition module is used to detect the first temperature of the motor; The controller is electrically connected to the motor and the temperature acquisition module, and the controller is configured as follows: Acquire a first temperature output by the temperature acquisition module and detect a load current of the motor; A second temperature of the motor is determined according to the first temperature and a load current of the motor, and an operating state of the motor is controlled based on the load current and the second temperature.

2. The electric tool according to claim 1, characterized in that: The temperature acquisition module includes a circuit board and a temperature sensing element mounted on the circuit board. The Hall plate includes a soldering pad. The circuit board is soldered to the Hall plate via the soldering pad. There is no electrical connection between the circuit board and the Hall plate.

3. The electric tool according to claim 2, characterized in that: The Hall plate is provided with a through hole for dissipating heat from the motor.

4. The electric tool according to claim 3, characterized in that: The circuit board is arranged on the surface of the Hall plate facing away from the motor and the circuit board at least partially covers the through hole, or the circuit board is located on the surface of the Hall plate facing the motor; wherein the temperature sensing element is arranged on the surface of the circuit board facing the motor.

5. The electric tool according to claim 2, characterized in that: The temperature sensing element is arranged on the side of the circuit board and the Hall plate where the pad is not welded. The temperature sensing element is a pin-type thermistor element. The temperature sensing element is led out through wiring and arranged near the motor.

6. The electric tool according to claim 1, characterized in that: The controller is configured to: When the second temperature is greater than the third temperature, the motor is controlled to stop working.

7. The electric tool according to claim 1, characterized in that: The controller is configured to: When the load current is less than or equal to a first preset current, the motor is controlled to operate according to the first temperature.

8. The electric tool according to claim 7, characterized in that: The controller is configured to: When the first temperature is greater than a fourth temperature, the motor is controlled to stop.

9. The electric tool according to claim 1, characterized in that: The controller is configured to: When the load current is greater than a first preset current and less than or equal to a second preset current, the working state of the motor is controlled according to the second temperature.

10. The electric tool according to claim 1, characterized in that: The formula for calculating the second temperature is: T2=T1+k×(I2-I1)+T3 Among them, T1 is the first temperature, T2 is the second temperature, T3 is the preset temperature, k is the setting coefficient, I1 is the first preset current, and I2 is the load current.

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