A piano key switch and its control circuit

Abstract

This utility model discloses a piano key switch and its control circuit, relating to the field of piano key switch technology. It solves the technical problem that current piano key switch control circuits require an additional switch to disconnect the mains power from the circuit board, leading to complex circuit design and high cost. The piano key switch includes multiple key components; each key component includes a key rod, an insulating block, a first stationary contact, a second stationary contact, a first moving contact, and a second moving contact; the key rod is movably connected above the insulating block; the first and second moving contacts are respectively disposed on opposite sides of the insulating block; the first stationary contact is disposed on the other side of the first moving contact; the second stationary contact is disposed on the other side of the second moving contact; the insulating block is used to push the first and second moving contacts laterally, so that the first moving contact contacts contact the first stationary contact, and the second moving contact contacts the second stationary contact. The switch and circuit provided by this utility model have a simple structure and low cost.

Description

Technical Field

[0001] This utility model relates to the field of piano key switch technology, and in particular to a piano key switch and its control circuit. Background Technology

[0002] With the continuous development of technology, brushless DC motors (BLDC) have been widely used in household appliances, industrial equipment, power tools and other fields due to their advantages such as high efficiency, low noise and long life. Traditional brushless DC motors usually use electronic controllers (such as MCUs or dedicated driver chips) for speed regulation and commutation control, while power supply switching relies on mechanical switches or relays.

[0003] In existing technology, key switches (push-button switches) are commonly used to control the start and stop of brushless DC motors. However, current key switches typically require the use of other switches. Because current key switches can only disconnect the motor from the power supply, but not the circuit board (PCB) from the mains power, this poses a safety hazard. Therefore, an additional switch is usually included to control the circuit board's connection to the mains power. However, adding extra switching components and wiring increases circuit complexity and leads to higher manufacturing costs.

[0004] In the process of developing this utility model, the applicant discovered at least the following problems in the prior art:

[0005] In current piano key switch control circuits, an additional switch is needed to disconnect the mains power from the circuit board, which leads to complex circuit design and increased costs. Utility Model Content

[0006] The purpose of this utility model is to provide a piano key switch and its control circuit to solve the technical problem that existing piano key switch control circuits require an additional switch to disconnect the mains power from the circuit board, leading to complex circuit design and increased costs. The various technical effects of the preferred solutions provided by this utility model are detailed below.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] This utility model provides a piano key switch, including multiple key assemblies and a base; the multiple key assemblies are fixedly connected to the base; each key assembly includes a key rod, an insulating block, a first stationary contact, a second stationary contact, a first movable contact, and a second movable contact; the key rod is movably connected above the insulating block; the first movable contact and the second movable contact are respectively disposed on both sides of the insulating block; the first stationary contact is disposed on the other side of the first movable contact; the second stationary contact is disposed on the other side of the second movable contact; the insulating block is used to simultaneously push the first movable contact and the second movable contact to move laterally, so that the first movable contact contacts the first stationary contact, and the second movable contact contacts the second stationary contact.

[0009] Optionally, a crossbeam is fixedly connected below the key rod. When the key rod moves down, it drives the crossbeam to push the insulating block down.

[0010] Optionally, both the first movable contact and the second movable contact have protrusions on the side facing the insulating block; when the insulating block moves downward, the protrusions push the first movable contact and the second movable contact to move outward.

[0011] Optionally, the insulating block is trapezoidal in shape, and the material of the insulating block is plastic, rubber, or resin.

[0012] A control circuit for a piano key switch, comprising any of the piano key switches described above.

[0013] Optionally, the control circuit further includes a control chip U1; the first stationary contact is connected to the live wire of the mains power; the first moving contact is connected to the input live wire of the control circuit; the second stationary contact is grounded; and the second moving contact is connected to the input terminal of the control chip U1.

[0014] Optionally, the number of button components is three, namely a first button component, a second button component, and a third button component.

[0015] Optionally, the control circuit further includes resistors R1, R2, R3, and R4 connected in series; the other end of resistor R1 is connected to a reference voltage; the other end of resistor R4 is grounded; the input terminal of the control chip U1 is connected between resistors R1 and R4; the second moving contact of the first button assembly is connected between resistors R3 and R4; the second moving contact of the second button assembly is connected between resistors R2 and R3; and the second moving contact of the third button assembly is connected between resistors R1 and R2.

[0016] Optionally, the control circuit further includes a resistor R5 and a capacitor C1; one end of the resistor R5 is connected between the resistor R1 and the resistor R2, and the other end is connected to the input terminal of the control chip U1; one end of the capacitor C1 is connected between the resistor R5 and the control chip U1, and the other end is grounded.

[0017] Optionally, the control chip U1 is model FG8692S.

[0018] Implementing one of the above-described technical solutions of this utility model has the following advantages or beneficial effects:

[0019] The piano key switch provided by this utility model has two sets of stationary and moving contacts on a key assembly. One set of stationary and moving contacts can be connected to the mains power, and the other set can be connected to the power supply of the circuit board. This allows a single piano key switch to simultaneously disconnect the motor from the power supply and disconnect the circuit board from the mains power, eliminating the need for an additional switch to disconnect the mains power. This reduces the complexity of the circuit design, the number of electrical components used, and thus reduces production costs. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0021] Figure 1 This is a schematic diagram of the structure of the piano key switch according to Embodiment 1 of this utility model;

[0022] Figure 2 This is a schematic diagram of the structure of the present invention when a piano key switch is closed;

[0023] Figure 3 This is the first circuit diagram of the control circuit for the piano key switch in Embodiment 2 of this utility model;

[0024] Figure 4 This is the second circuit diagram of the control circuit for the piano key switch in Embodiment 2 of this utility model;

[0025] In the diagram: 41, key rod; 411, crossbeam; 42, insulating block; 43, first stationary contact piece; 44, first moving contact piece; 45, second stationary contact piece; 46, second moving contact piece; 47, protrusion. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this utility model clearer, various exemplary embodiments described below will be referenced to the accompanying drawings, which form part of the exemplary embodiments, illustrating various exemplary embodiments that may be adopted to implement this utility model. Unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. It should be understood that they are merely examples of processes, methods, and apparatuses consistent with some aspects of this utility model disclosed as detailed in the appended claims, and other embodiments may be used, or structural and functional modifications may be made to the embodiments listed herein without departing from the scope and spirit of this utility model.

[0027] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," etc., indicate the orientation or positional relationship based on the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the referred element must have a specific orientation, or be constructed and operated in a specific orientation. The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. The term "multiple" means two or more. The terms "connected" and "linked" should be interpreted broadly, for example, they can be fixed connections, detachable connections, integral connections, mechanical connections, electrical connections, communication connections, direct connections, indirect connections through an intermediate medium, and can be the internal connection of two elements or the interaction relationship between two elements. The term "and / or" includes any and all combinations of one or more of the related listed items. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0028] To illustrate the technical solution described in this utility model, specific embodiments are described below, showing only the parts related to the embodiments of this utility model.

[0029] Example 1:

[0030] like Figure 1 and Figure 2As shown, this utility model provides a piano key switch, including multiple key assemblies and a base (not shown in the figure); the multiple key assemblies are fixedly connected to the base; the key assembly includes a key rod 41, an insulating block 42, a first stationary contact 43, a second stationary contact 45, a first moving contact 44, and a second moving contact 46; the key rod 41 is movably connected above the insulating block 42; the first moving contact 44 and the second moving contact 46 are respectively disposed on both sides of the insulating block 42; the first stationary contact 43 is disposed on the other side of the first moving contact 44; the second stationary contact 45 is disposed on the other side of the second moving contact 46; the insulating block 42 is used to simultaneously push the first moving contact 44 and the second moving contact 46 to move laterally, so that the first moving contact 44 contacts the first stationary contact 43, and the second moving contact 46 contacts the second stationary contact 45. When a force is applied to the key rod 41 to make it move, the key rod 41 will drive the insulating block 42 connected to it to move. When the insulating block 42 moves, it pushes the first moving contact 44 and the second moving contact 46 on both sides to move laterally. When the first moving contact 44 and the second moving contact 46 move to a certain extent, the first moving contact 44 will contact the first stationary contact 43, and the second moving contact 46 will contact the second stationary contact 45. This contact can realize the conduction of the circuit, thereby realizing the function of the button to control the circuit to open and close. For example, in a fan, hair dryer or range hood, when the button 41 is pressed, the corresponding operation is triggered by the contact of these contacts.

[0031] The piano key switch provided in this embodiment has two sets of stationary and moving contacts on a key assembly. One set of stationary and moving contacts can be connected to the mains power, while the other set is connected to the power supply of the circuit board. This allows a single piano key switch to simultaneously disconnect the motor from the power supply and disconnect the circuit board from the mains power, eliminating the need for an additional switch to disconnect the mains power. This reduces the complexity of the circuit design, the number of electrical components used, and thus lowers the cost.

[0032] As an alternative implementation method, such as Figure 2 As shown, a crossbeam 411 is fixedly connected below the key rod 41. When the key rod 41 moves downward, it drives the crossbeam 411 to push the insulating block 42 downward. Specifically, the key rod 41 and the crossbeam 411 are an integral structure. When the key rod 41 is subjected to external force and moves downward, since the key rod 41 and the crossbeam 411 are an integral structure, the key rod 41 will move downward along with the crossbeam 411. During the downward movement, the crossbeam 411 pushes the insulating block 42, causing the insulating block 42 to move downward as well. By using the movement of the key rod 41 to drive the movement of the insulating block 42, the circuit switching function is realized. The crossbeam 411 increases the contact area between the key rod 41 and the insulating block 42, making the pressure required when pressing less.

[0033] As an alternative implementation, both the first movable contact 44 and the second movable contact 46 have protrusions 47 on the side facing the insulating block 42. When the insulating block 42 moves downward, it pushes the protrusions 47 to move the first movable contact 44 and the second movable contact 46 outward. When the insulating block 42 is in its original position, it does not contact the first movable contact 44 and the second movable contact 46 on both sides. When the insulating block 42 moves downward, it is held in place by the protrusions 47 on both sides, thereby pushing the protrusions 47 to both sides during the downward movement, thereby causing the first movable contact 44 and the second movable contact 46 to move laterally until the first movable contact 44 contacts the first stationary contact 43 and the second movable contact 46 contacts the second stationary contact 45.

[0034] As an alternative implementation, the insulating block 42 is trapezoidal in shape, which makes it easier to push the insulating block 42 downwards. The insulating block 42 is made of plastic, rubber, or resin. All three materials have good insulation properties and can prevent the conduction of current, thereby ensuring the safe operation of electrical equipment and the safety of personnel.

[0035] The embodiment is merely a special case and does not indicate that this utility model is implemented in such a way.

[0036] Example 2:

[0037] The difference between this embodiment two and embodiment one is that: Figure 3 As shown, a control circuit for a piano key switch is provided, including a piano key switch as described in any of Embodiment 1. Figure 3 K1 in this example refers to the piano key switch provided in Embodiment 1. Specifically, the control circuit also includes a control chip U1; the first stationary contact 43 is connected to the live wire of the mains power; the first moving contact 44 is connected to the input live wire of the control circuit; the second stationary contact 45 is grounded; and the second moving contact 46 is connected to the input terminal (AIO8 pin) of the control chip U1. The moving contact is opposite to the stationary contact. The stationary contact is generally stationary, while the moving contact can move. The moving contact achieves the switching of the circuit by contacting or separating from the stationary contact. Mains power refers to the alternating current used in daily life. The live wire is a conductor with voltage, which has a potential difference with the neutral wire and can provide power to electrical equipment. Connecting the first stationary contact 43 to the live wire of the mains power means that the stationary contact will be continuously energized, and the voltage is usually 220V (single-phase mains power). The input live wire of the control circuit refers to the live wire that is connected to the power input terminal when the control circuit board draws power from the mains power. The first moving contact 44 is connected to the live wire at this time.

[0038] When the first moving contact 44 contacts the first stationary contact 43, the live wire of the mains power is connected to the input live wire of the controlled circuit, and the control circuit of this embodiment will be powered on and work. When the two are separated, the circuit is disconnected, and the control circuit stops working. This circuit design ensures that when the key assembly of the piano switch K1 is pressed, the first moving contact 44 and the first stationary contact 43 are turned on, the control circuit is connected to the mains power, and the second moving contact 46 and the second stationary contact 45 are also turned on, providing operating power to the control chip U1. The output of the control chip U1 is connected to the brushless DC motor to control the brushless DC motor, making it start or stop. When the piano switch is turned off, the connection between the control chip U1 and the power supply, as well as the connection between the mains power and the control circuit, can be disconnected simultaneously, eliminating the need for additional switching elements, making the circuit structure of this embodiment simple and low-cost.

[0039] Specifically, such as Figure 4 As shown, control chip U1 is connected to the three-phase interface (i.e., U, V, W interface) of the brushless DC motor through pins AIO0, AIO1, AIO2, AIO3, and AIO9. Pins AIO0 and AIO1 of control chip U1 are both connected to the UL interface of the brushless DC motor through MOSFET U2B, used to input a low level to phase A of the brushless DC motor; pins AIO0 and AIO1 of control chip U1 are both connected to the UH interface of the brushless DC motor through MOSFETs U2B and U2A respectively, used to input a high level to phase A of the brushless DC motor; pin AIO9 of control chip U1 is connected to the VL interface of the brushless DC motor through MOSFET U3B, used to input a low level to phase B of the brushless DC motor; control chip U... Pin AIO9 of control chip U1 is connected to the VH interface of the brushless DC motor via MOSFETs U3B and U3A, respectively, to input a high level to phase B of the brushless DC motor. Pins AIO2 and AIO3 of control chip U1 are both connected to the WL interface of the brushless DC motor via MOSFET U4B, respectively, to input a low level to phase C of the brushless DC motor. Pins AIO2 and AIO3 of control chip U1 are both connected to the WH interface of the brushless DC motor via MOSFETs U4B and U4A, respectively, to input a high level to phase C of the brushless DC motor. These connections enable three-phase control of the brushless DC motor.

[0040] As an alternative implementation, the number of button components is three: a first button component, a second button component, and a third button component. For example... Figure 3As shown, the control circuit also includes resistors R1, R2, R3, and R4 connected in series. The other end of resistor R1 is connected to a reference voltage; the other end of resistor R4 is grounded; the input terminal (AIO8 pin) of the control chip U1 is connected between resistors R1 and R4; the second moving contact 46 of the first button assembly (i.e., pin 1 of the key switch K1) is connected between resistors R3 and R4; the second moving contact 46 of the second button assembly (i.e., pin 2 of the key switch K1) is connected between resistors R2 and R3; and the second moving contact 46 of the third button assembly (i.e., pin 3 of the key switch K1) is connected between resistors R1 and R2. By setting up three button assemblies, different button presses can be used to adjust the motor's gear.

[0041] The following will combine Figure 3 The working principle of the control circuit for the piano key switch provided in this embodiment will be explained in detail below:

[0042] The reference voltage is set to 3.3V. When no key is pressed, the reference voltage is grounded through resistors R1, R2, R3, and R4. The AI08 port (i.e., the input terminal) of the control chip U1 can detect a voltage of approximately 2.475V, thus setting the speed of the motor connected to the output terminal of the control chip U1 to 0. Since the 0 pin of the key switch K1 is grounded (i.e., the second stationary contact 45 of the first key assembly, the second key assembly, and the third key assembly are grounded), when the key switch K1 is closed at pin 1 (i.e., the first key assembly is pressed), S1 is grounded, and the reference voltage is grounded through resistors R1, R2, R3, and R4. When pin 2 and resistor R3 are grounded, control chip U1 can detect a voltage of approximately 1.32V, setting the motor speed to level 1. When key switch K1 is closed at pin 2 (i.e., the second key assembly is pressed), pin S2 is grounded, and the reference voltage is grounded through resistors R1 and R2. Control chip U1 can detect a voltage of approximately 1.1V, setting the motor speed to level 2. When key switch K1 is closed at pin 3 (i.e., the third key assembly is pressed), pin S2 is grounded, and the reference voltage is grounded through resistor R1. Control chip U1 can detect a voltage of approximately 0V, setting the motor speed to level 3. This achieves the adjustment of different motor speeds.

[0043] Furthermore, the control method of the control circuit of the key switch in this embodiment is as follows: First, the key switch, control chip U1 and DC brushless motor are initialized, that is, the circuit is powered on to prepare for the normal operation of the subsequent circuit; when a key component in the key switch K1 is pressed, the key switch K1 sends the corresponding control signal of the key component to the control chip U1; the microprocessor of the control chip U1 receives the control signal, generates the corresponding control command according to the control signal, and sends it to the DC brushless motor, thereby controlling the speed of the DC brushless motor to achieve different wind speeds.

[0044] As an alternative implementation, the control circuit also includes a resistor R5 and a capacitor C1; one end of resistor R5 is connected between resistors R1 and R2, and the other end is connected to the input terminal of control chip U1; one end of capacitor C1 is connected between resistor R5 and control chip U1, and the other end is grounded. Setting resistor R5 and capacitor C1 at the input terminal of control chip U1 can filter the voltage input to control chip U1 to smooth the output voltage.

[0045] As an alternative implementation, the control chip U1 is model FG8692S. The FG8692S is a self-developed 32-bit motor control MUC that can precisely control parameters such as motor speed and direction; it has a built-in 40V pre-driver that can directly drive corresponding power devices, simplifying external circuit design; its operating frequency range is 64MHz to 96MHz, within which it can operate stably. Generally, the higher the frequency, the faster the chip's processing speed.

[0046] The above description is merely a preferred embodiment of the present utility model. Those skilled in the art will understand that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the present utility model. Furthermore, under the teachings of the present utility model, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the present utility model. Therefore, the present utility model is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present utility model.

Claims

1. A piano key switch, characterized in that, It includes multiple button components and a base; the multiple button components are fixedly connected to the base; The button assembly includes a key lever, an insulating block, a first stationary contact, a second stationary contact, a first movable contact, and a second movable contact; the key lever is movably connected above the insulating block; the first movable contact and the second movable contact are respectively disposed on both sides of the insulating block; the first stationary contact is disposed on the other side of the first movable contact; the second stationary contact is disposed on the other side of the second movable contact; the insulating block is used to simultaneously push the first movable contact and the second movable contact to move laterally, so that the first movable contact contacts the first stationary contact, and the second movable contact contacts the second stationary contact.

2. A piano key switch according to claim 1, characterized in that, A crossbeam is fixedly connected below the key rod. When the key rod moves down, it drives the crossbeam to push the insulating block down.

3. A piano key switch according to claim 2, characterized in that, Both the first movable contact and the second movable contact have protrusions on the side facing the insulating block; when the insulating block moves down, the protrusions push the first movable contact and the second movable contact to move outward.

4. A piano key switch according to claim 1, characterized in that, The insulating block is trapezoidal in shape and is made of plastic, rubber, or resin.

5. A control circuit for a piano key switch, characterized in that, Includes a piano key switch as described in any one of claims 1-4.

6. The control circuit for a piano key switch according to claim 5, characterized in that, The control circuit also includes a control chip U1; the first stationary contact is connected to the live wire of the mains power; the first moving contact is connected to the input live wire of the control circuit; the second stationary contact is grounded; and the second moving contact is connected to the input terminal of the control chip U1.

7. The control circuit for a piano key switch according to claim 6, characterized in that, The number of button components is three, namely the first button component, the second button component, and the third button component.

8. The control circuit for a piano key switch according to claim 7, characterized in that, The control circuit further includes resistors R1, R2, R3, and R4 connected in series; the other end of resistor R1 is connected to a reference voltage; the other end of resistor R4 is grounded; the input terminal of the control chip U1 is connected between resistors R1 and R4; the second moving contact of the first button assembly is connected between resistors R3 and R4; the second moving contact of the second button assembly is connected between resistors R2 and R3; and the second moving contact of the third button assembly is connected between resistors R1 and R2.

9. The control circuit for a piano key switch according to claim 8, characterized in that, The control circuit also includes a resistor R5 and a capacitor C1; one end of the resistor R5 is connected between the resistor R1 and the resistor R2, and the other end is connected to the input terminal of the control chip U1; one end of the capacitor C1 is connected between the resistor R5 and the control chip U1, and the other end is grounded.

10. The control circuit for a piano key switch according to claim 6, characterized in that, The control chip U1 is model FG8692S.

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