Speed regulation rotary switch

Abstract

The utility model discloses a speed regulation rotary switch, which comprises a support, a speed regulation knob and a PCB (printed circuit board) fixedly arranged between the speed regulation knob and the support, the support is provided with a rotating shaft hole, the speed regulation knob is provided with a knob rotating shaft rotationally connected in the rotating shaft hole, and one end of the knob rotating shaft is provided with an elastic limiting buckle. According to the technical scheme, when the speed regulation knob is installed, the knob rotating shaft is directly inserted into the rotating shaft hole of the support, the limiting buckle elastically abuts against the limiting clamping table in a clamped mode to form automatic locking, and the purpose of rapid assembly is achieved. The limiting buckle and the limiting clamp are matched in a limiting mode to prevent the rotary knob rotating shaft from being separated from the rotating shaft hole in the axial direction, the installation stability is good, the rotating smoothness is improved, the installation structure of the speed adjusting rotary knob is simple, installation parts are reduced, tool-free installation is achieved, the installation efficiency is improved, and the production cost is reduced.

Description

Technical Field

[0001] This utility model relates to the field of electrical switch technology, specifically to a speed-regulating rotary switch. Background Technology

[0002] Speed ​​control switches are widely used in handheld power tools and household appliances, such as electric drills, egg beaters, electric wrenches, and electric screwdrivers. A speed control switch is an electronic switch that uses electronic circuits or microprocessor chips to change the motor's speed by changing the motor's number of stages, voltage, current, frequency, etc., so as to enable the motor to achieve higher performance.

[0003] Existing Chinese patent document CN211376505 discloses an electronic speed control switch, which includes a speed adjustment component and an acceleration component disposed on the left and right sides of a bracket. The speed adjustment component includes a PCB board, a speed control knob, and a contact installed inside the speed control knob. The PCB board is fixedly connected to the speed control knob on the bracket by self-tapping screws, and the speed control knob rotates around the self-tapping screws as the axis. The exposed contacts on the PCB board are coupled to the contact installed inside the speed control knob. The contact includes four contact terminals, and its ends are provided with mounting holes. The contact is sleeved on the mounting post through the mounting holes, so that the contact is displaced when the speed control knob is rotated. From the structure of the above electronic speed control switch, it can be seen that the following problems still exist: 1. This type of speed control knob is connected to the bracket by a self-tapping screw and rotates around the self-tapping screw. The installation structure is complex, there are many installation parts, the setting cost is high, and the frequent rotation of the speed control knob will aggravate the wear between it and the screw, resulting in a stiff adjustment feel. Moreover, under high vibration and load working environment, the screw is prone to gradual loosening, affecting the structural stability; 2. The contact is a traditional brush structure, which is sleeved on the mounting post through the mounting hole and needs to be fixed by heat riveting. The assembly process is inconvenient, and the contact is prone to deformation during the installation operation, affecting the contact performance. Utility Model Content

[0004] Therefore, the technical problem to be solved by this utility model is to overcome the problems of the existing speed control knob being connected to the bracket by a self-tapping screw and rotating around the self-tapping screw, which has a complex installation structure, high setting cost, and poor structural stability. Thus, a speed control rotary switch with a simple installation structure, improved installation efficiency, reduced production cost, and improved knob rotation smoothness is provided.

[0005] To solve the above-mentioned technical problems, this utility model provides a speed-regulating rotary switch, including a bracket and a speed-regulating knob rotatably disposed on the bracket, and a PCB board fixedly disposed between the speed-regulating knob and the bracket. The bracket is provided with a pivot hole, and the speed-regulating knob has a knob pivot rotatably connected to the pivot hole. A limiting structure is provided between the knob pivot and the pivot hole to restrict the knob pivot from moving axially away from the pivot hole. The limiting structure includes a limiting plate disposed in the pivot hole and a set of limiting buckles disposed at one end of the knob pivot and elastically abutting against the limiting plate to form a limiting engagement.

[0006] In the aforementioned speed-regulating rotary switch, the speed-regulating knob includes a circular knob baffle and a handle portion connected to the outer periphery of the knob baffle. The knob shaft is a hollow shaft integrally formed on the inner side of the knob baffle.

[0007] In the aforementioned speed-regulating rotary switch, a set of limit buckles includes two elastic buckles extending axially along the knob shaft and disposed at one end of the knob shaft.

[0008] In the aforementioned speed-regulating rotary switch, the limiting plate is an annular plate formed on the inner wall of the rotating shaft hole.

[0009] In the aforementioned speed-regulating rotary switch, the end of the elastic buckle is provided with a guide arc slope.

[0010] In the aforementioned speed-regulating rotary switch, the inner side of the handle portion is provided with multiple gear slots at intervals, the top of the bracket is provided with a mounting groove with an opening facing the handle portion, the mounting groove is provided with a connected compression spring and a steel sleeve, the lower end of the steel sleeve is provided with a concave hole suitable for accommodating the compression spring, and its upper end is a round shaft end that extends out of the mounting groove and contacts the gear slot.

[0011] The aforementioned speed-regulating rotary switch also includes an elastic movable contact piece positioned and mounted on the knob baffle via a connecting structure. The PCB board is provided with a contact assembly that engages with the elastic contact piece. When the elastic movable contact piece is coupled to the contact assembly, the speed-regulating electrical circuit on the PCB board is connected.

[0012] In the aforementioned speed-regulating rotary switch, the elastic movable contact includes two V-shaped contact portions extending protruding towards one side of the PCB board. The contact assembly includes a first contact portion extending along the movement trajectory of the elastic movable contact and disposed on the PCB board, and a plurality of second contact portions sequentially spaced along the movement trajectory of the elastic movable contact and distributed on one side of the first contact portion. One of the V-shaped contact portions always slides in contact with the first contact portion, while the other V-shaped contact portion slides and switches between the plurality of second contact portions.

[0013] In the aforementioned speed-regulating rotary switch, the connecting structure includes a positioning groove disposed on the knob baffle for mounting the elastic movable contact piece, and a positioning boss extending along the length of the positioning groove and disposed in the positioning groove; the elastic movable contact piece includes two connecting pieces connected to the two ends of two V-shaped contact portions, and a connecting groove formed between the two V-shaped contact portions; when the elastic movable contact piece is inserted into the positioning groove, the positioning boss passes through the connecting groove, so that the two connecting pieces elastically abut against the two ends of the positioning boss to form a positioning fit.

[0014] In the aforementioned speed-regulating rotary switch, a first gap and a second gap with different lengths are formed between the two ends of the positioning boss and the two ends of the positioning groove. One of the connecting pieces is limited in the first gap, and the other connecting piece is disposed in the second gap and can move when the elastic movable contact piece is pressed. Multiple convex ribs that contact the bottom of the elastic movable contact piece are arranged at intervals in the positioning groove.

[0015] Compared with the prior art, the technical solution of this utility model has the following advantages:

[0016] 1. The speed-regulating rotary switch provided by this utility model includes a knob shaft rotatably connected to the shaft hole of the bracket. An elastic limit buckle is provided at one end of the knob shaft, and a corresponding limit plate is provided in the shaft hole to cooperate with the limit buckle. The advantage of this technical solution is that when installing the speed-regulating knob, the knob shaft is directly inserted into the shaft hole of the bracket, and the elastic limit buckle abuts against the limit plate to form an automatic locking, achieving assembly in seconds. Simultaneously, the limiting cooperation between the limit buckle and the limit plate prevents the knob shaft from axially disengaging from the shaft hole, ensuring a stable and reliable rotatable connection of the knob shaft in the shaft hole. The cylindrical surface fit between the knob shaft and the shaft hole ensures uniform stress distribution, reduces stress concentration, and improves rotational smoothness, thus solving problems such as loosening, wear, and complex assembly associated with traditional screw connections. This speed-regulating knob has a simple installation structure, reduces installation parts, achieves tool-free installation, improves installation efficiency, and reduces production costs.

[0017] 2. The speed-regulating rotary switch provided by this utility model includes two elastic buckles set at one end of the knob shaft, and the limiting buckle is an annular buckle formed on the inner wall of the shaft hole. With this structure, when the knob shaft drives the elastic buckles to be inserted into the shaft hole, the elastic buckles automatically open and rebound to lock after reaching the position of the annular step. No tools or auxiliary operation are required throughout the process, making installation convenient and quick. The cooperation between the annular step and the elastic buckles can strictly limit the axial displacement of the rotating shaft, so as to realize the knob shaft positioning and rotating connection in the shaft hole. Furthermore, the hook structure of the elastic buckles and the annular step forms a mechanical interlock, which can withstand greater axial tensile force and improve the pull-out resistance.

[0018] 3. The speed-regulating rotary switch provided by this utility model, based on the coordinated design of the annular step and elastic buckle between the knob shaft and the shaft hole, not only realizes the core functions of axial limiting and quick assembly, but also plays a role in reducing costs, extending life and improving product performance. It can be well applied to high-frequency operation speed-regulating rotary switch products.

[0019] 4. In the speed-regulating rotary switch provided by this utility model, multiple gear slots are provided at intervals on the inner side of the handle of the speed-regulating knob, and a compression spring and a steel sleeve are provided in the mounting groove at the top of the bracket. The steel sleeve is longer in the mounting groove, and compared with the traditional steel ball, it will not fall out of the mounting groove, resulting in better installation stability. With this structure, the multiple gears of the speed-regulating knob are realized through the cooperation of the gear slots and the steel sleeve. The round shaft end of the steel sleeve contacts the gear slot under the action of the compression spring. When the speed-regulating knob is rotated to adjust the gear, the round shaft end of the steel sleeve moves back and forth between the multiple gear slots, thereby clearly sensing the gear shift and realizing the gear positioning. The gear control is accurate and in place, and the adjustment operation is convenient.

[0020] 5. In the speed-regulating rotary switch provided by this utility model, the elastic moving contact includes two connecting pieces connected to the two ends of two V-shaped contact portions, and a connecting groove formed between the two V-shaped contact portions. When the elastic moving contact is installed into the positioning groove of the speed-regulating knob, it will produce a slight deformation, causing the positioning boss set in the positioning groove to pass into the connecting groove. At the same time, the two connecting pieces elastically abut against the two ends of the positioning boss to form a positioning fit. That is, the elastic moving contact and the positioning boss form an elastic snap-fit ​​fit in the positioning groove. In this way, the elastic moving contact is installed on the adjustment knob, and the installation is stable and reliable, thereby avoiding the use of the traditional contact component hot riveting fixation method. The installation structure of this elastic moving contact is simple, and the installation is convenient and quick, improving assembly efficiency. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 A three-dimensional structural schematic diagram of the speed-regulating rotary switch provided for the utility model;

[0023] Figure 2 This is a cross-sectional structural diagram of a speed-regulating rotary switch of a utility model.

[0024] Figure 3 A schematic diagram of the split structure of a speed-regulating rotary switch of a utility model;

[0025] Figure 4 This is a schematic diagram of the installation structure of the speed control knob and the elastic moving contact piece of the utility model.

[0026] Figure 5 This is a schematic diagram of the speed control knob of a utility model.

[0027] Figure 6 This is a schematic diagram of the structure of the elastic movable contact piece of the utility model.

[0028] Figure Descriptions: 1. Bracket; 11. Rotary shaft hole; 2. Speed ​​control knob; 21. Knob shaft; 22. Knob baffle; 23. Handle part; 24. Gear slot; 3. PCB board; 31. First contact part; 32. Second contact part; 4. Limiting plate; 5. Limiting buckle; 61. Compression spring; 62. Steel sleeve; 7. Elastic moving contact piece; 71. V-shaped contact part; 72. Connecting piece; 73. Connecting groove; 8. Positioning groove; 81. First gap; 82. Second gap; 83. Raised rib; 9. Positioning boss. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0030] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0031] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0032] Example

[0033] This utility model provides, for example Figure 1-6The speed-adjustable rotary switch shown is used on an egg beater. It includes a bracket 1 and a speed-adjustable knob 2 rotatably disposed on the bracket 1, and a PCB board 3 fixedly disposed between the speed-adjustable knob 2 and the bracket 1. The bracket 1 is provided with a pivot hole 11, and the PCB board 3 is provided with a through hole through which the knob pivot 21 can pass. The speed-adjustable knob 2 has a knob pivot 21 rotatably connected to the pivot hole 11. A limiting structure is provided between the knob pivot 21 and the pivot hole 11 to restrict the knob pivot 21 from moving axially away from the pivot hole 11. The limiting structure includes a limiting plate 4 disposed in the pivot hole 11, and a set of limiting buckles 5 disposed at one end of the knob pivot 21 and elastically abutting against the limiting plate 4 to form a limiting engagement.

[0034] The above-described implementation method is the core technical solution of this embodiment. When installing the speed control knob 2, the knob shaft 21 is directly inserted into the shaft hole 11 of the bracket 1. The limit buckle 5 elastically abuts against the limit plate 4 to form an automatic locking, thereby achieving assembly in seconds. At the same time, the limiting fit between the limit buckle 5 and the limit plate 4 is used to prevent the knob shaft 21 from axially disengaging from the shaft hole 11, thereby ensuring that the knob shaft 21 is stably and reliably connected in the shaft hole 11. Since the knob shaft 21 and the shaft hole 11 adopt a cylindrical surface fit, the stress is evenly distributed, stress concentration is reduced, and the rotation smoothness is improved. This solves the problems of loosening, wear, and complex assembly of traditional screw connections. This speed control knob installation structure is simple, reduces installation parts, achieves tool-free installation, improves installation efficiency, and reduces production costs.

[0035] The following is combined Figure 1-3 The specific installation method of the speed control knob is described in detail below:

[0036] The speed control knob 2 includes a circular knob baffle 22 and a handle portion 23 connected to the outer periphery of the knob baffle 22. The knob shaft 21 is a hollow shaft integrally formed on the inner side of the knob baffle 22. The integral structure has good stability and is easy to manufacture. This knob and knob shaft 21 are directly injection molded as a whole, which is convenient to manufacture and suitable for mass production. During assembly, it only needs to be inserted into the shaft hole 11 of the bracket 1 to realize integrated module assembly, save assembly time, and improve the coaxiality and rotation accuracy of the knob shaft 21. In a further preferred configuration, a set of the limiting buckles 5 includes two elastic buckles extending axially along the knob shaft 21 at one end of the knob shaft 21. The limiting locking platform 4 is an annular platform formed on the inner wall of the shaft hole 11. With this structure, when the knob shaft 21 drives the elastic buckles to be inserted into the shaft hole 11, the elastic buckles automatically open and spring back to lock after reaching the annular step position. No tools or auxiliary operations are required throughout the process, making installation convenient and quick. The cooperation between the annular step and the elastic buckles can strictly limit the axial displacement of the rotating shaft, so as to realize the knob shaft 21 being positioned and rotated in the shaft hole 11. Furthermore, the hook structure between the elastic buckles and the annular step forms a mechanical interlock, which can withstand greater axial tensile force and improve the pull-out resistance.

[0037] The end of the elastic buckle is provided with a guide arc slope. The guide arc slope can guide the buckle to slide smoothly into the correct installation position of the rotating shaft hole 11, avoiding jamming or misalignment, enhancing assembly guidance, reducing insertion resistance, and the guide arc slope design may reduce stress concentration and extend the service life of the elastic buckle.

[0038] In summary, the coordinated design of the knob shaft 21 and the shaft hole 11 through the annular step and the elastic buckle not only realizes the core functions of axial limiting and quick assembly, but also reduces costs, extends lifespan, and improves product performance. It can be well applied to high-frequency operating speed-regulating rotary switch products.

[0039] To improve the feel of the speed control switch when adjusting the speed, such as Figure 4As shown, the inner side of the handle portion 23 is provided with multiple gear slots 24 at intervals. The top of the bracket 1 is provided with a mounting groove with an opening facing the handle portion 23. A compression spring 61 and a steel sleeve 62 are connected in the mounting groove. The lower end of the steel sleeve 62 is provided with a concave hole suitable for accommodating the compression spring 61, and its upper end is a round shaft end that extends out of the mounting groove and contacts the gear slot 24. The steel sleeve 62 is longer when inserted into the mounting groove, and compared with the traditional steel ball, it will not fall out of the mounting groove, resulting in better installation stability. With this structure, the multiple gears of the speed control knob 2 are achieved through the cooperation of the gear slots 24 and the steel sleeve 62. The round shaft end of the steel sleeve 62 contacts one of the gear slots 24 under the action of the compression spring 61. When the speed control knob is rotated to adjust the gear, the round shaft end of the steel sleeve 62 moves back and forth between multiple gear slots, thereby clearly sensing the gear shift and realizing gear positioning. The gear control is accurate and in place, and the adjustment operation is convenient.

[0040] In this embodiment, the speed-regulating rotary switch further includes an elastic movable contact 7 positioned and mounted on the knob baffle 22 via a connecting structure. The PCB board 3 is mounted on the bracket 1 via multiple sets of fixing posts. The PCB board 3 is provided with a contact assembly that engages with the elastic contact 7. When the elastic movable contact 7 is coupled to the contact assembly, the speed-regulating electrical circuit on the PCB board 3 is activated. Further features include... Figure 3 As shown, the elastic movable contact 7 includes two V-shaped contact portions 71 extending protruding towards one side of the PCB board 3. The contact assembly includes a first contact portion 31 extending along the movement trajectory of the elastic movable contact 7 and disposed on the PCB board 3, and a plurality of second contact portions 32 arranged sequentially at intervals along the movement trajectory of the elastic movable contact 7 and distributed on one side of the first contact portion 31. One of the V-shaped contact portions 71 always slides in contact with the first contact portion 31, while the other V-shaped contact portion 71 slides and switches between the plurality of second contact portions 32. With this structure, the speed control switch has two gears, which are divided into an off position and multiple speed control positions according to the number of second contact portions 32. When the speed control knob 2 is rotated, it drives the elastic movable contact 7 to slide and connect the first contact portion 31 and any one of the second contact portions 32, thereby conducting and forming a speed control electrical circuit with different resistance values, realizing multi-level adjustment control of the product speed control position.

[0041] The following combination Figure 3-5 The specific arrangement of the elastic movable contact piece is described in detail below:

[0042] The elastic movable contact piece 7 includes two connecting pieces 72 connected to the two ends of two V-shaped contact portions 71, and a connecting groove 73 formed between the two V-shaped contact portions 71. The connecting structure includes a positioning groove 8 provided on the knob baffle 22 for installing the elastic movable contact piece 7, and a positioning boss 9 extending along the length of the positioning groove 8 and provided in the positioning groove 8. When the elastic movable contact piece 7 is installed into the positioning groove 8, the positioning boss passes through the connecting groove 73, so that the two connecting pieces 72 elastically abut against the two ends of the positioning boss to form a positioning fit. That is, the elastic movable contact piece 7 and the positioning boss form an elastic snap fit in the positioning groove 8. In this way, the elastic movable contact piece is installed on the adjustment knob, and the installation is stable and reliable, thereby avoiding the use of traditional contact parts for hot riveting. This installation structure of the elastic movable contact piece 7 is simple, and the installation is convenient and quick, improving assembly efficiency.

[0043] In a further preferred configuration, a first gap 81 and a second gap 82 with different lengths are formed between the two ends of the positioning boss 9 and the two ends of the positioning groove 8, i.e., the length of the first gap 81 is less than the length of the second gap 82. One of the connecting pieces 72 is confined in the first gap 81, and the other connecting piece 72 is disposed in the second gap 82 and can move when the elastic movable contact piece 7 is compressed. Multiple raised ribs 83 are arranged at intervals in the positioning groove 8 to contact the bottom of the elastic movable contact piece 7. The raised ribs can reduce the friction of the elastic movable contact piece. This structural configuration, through the gap design, provides a buffer margin for the elastic movable contact piece under pressure, thereby consuming impact energy and providing sufficient gap position to ensure that the elastic movable contact piece can return to its original shape after the force is released. This avoids the elastic movable contact piece from permanent deformation or breakage due to long-term excessive compression, thereby protecting the elastic movable contact piece and extending its service life.

[0044] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A speed-regulating rotary switch, comprising a bracket (1) and a speed-regulating knob (2) rotatably disposed on the bracket (1), and a PCB board (3) fixedly disposed between the speed-regulating knob (2) and the bracket (1), characterized in that: The bracket (1) is provided with a pivot hole (11), and the speed control knob (2) has a knob pivot (21) rotatably connected in the pivot hole (11). A limiting structure is provided between the knob pivot (21) and the pivot hole (11) to restrict the knob pivot (21) from moving axially away from the pivot hole (11). The limiting structure includes a limiting plate (4) provided in the pivot hole (11) and a set of limiting buckles (5) provided at one end of the knob pivot (21) and elastically abutting against the limiting plate (4) to form a limiting fit.

2. The speed-regulating rotary switch according to claim 1, characterized in that: The speed control knob (2) includes a circular knob baffle (22) and a handle part (23) connected to the outer periphery of the knob baffle (22). The knob shaft (21) is a hollow shaft integrally formed on the inner side of the knob baffle (22).

3. The speed-regulating rotary switch according to claim 2, characterized in that: A set of the limiting buckles (5) includes two elastic buckles that extend axially along the knob shaft (21) and are disposed at one end of the knob shaft (21).

4. The speed-regulating rotary switch according to claim 3, characterized in that: The limiting plate (4) is an annular plate formed on the inner wall of the rotating shaft hole (11).

5. A speed-regulating rotary switch according to claim 3, characterized in that: The end of the elastic buckle is provided with a guide arc bevel.

6. A speed-regulating rotary switch according to claim 2, characterized in that: The inner side of the handle (23) is provided with a plurality of gear slots (24) spaced apart. The top of the bracket (1) is provided with a mounting groove with an opening facing the handle (23). The mounting groove is provided with a connected compression spring (61) and a steel sleeve (62). The lower end of the steel sleeve (62) is provided with a concave hole suitable for accommodating the compression spring (61), and its upper end is a round shaft end that extends out of the mounting groove and contacts the gear slot (24).

7. A speed-regulating rotary switch according to any one of claims 2-6, characterized in that: It also includes an elastic movable contact piece (7) that is positioned and installed on the knob baffle (22) by a connection structure. The PCB board (3) is provided with a contact assembly that engages with the elastic contact piece. When the elastic movable contact piece (7) is coupled to the contact assembly, the speed regulation electrical circuit on the PCB board (3) is turned on.

8. A speed-regulating rotary switch according to claim 7, characterized in that: The elastic movable contact (7) includes two V-shaped contact portions (71) extending protruding toward one side of the PCB board (3). The contact assembly includes a first contact portion (31) extending along the movement trajectory of the elastic movable contact (7) and disposed on the PCB board (3), and a plurality of second contact portions (32) arranged sequentially at intervals along the movement trajectory of the elastic movable contact (7) on the PCB board (3) and distributed on one side of the first contact portion (31). One of the V-shaped contact portions (71) always slides in contact with the first contact portion (31), and the other V-shaped contact portion (71) slides and switches between the plurality of second contact portions (32).

9. A speed-regulating rotary switch according to claim 8, characterized in that: The connection structure includes a positioning groove (8) on the knob baffle (22) for mounting the elastic movable contact piece (7), and a positioning boss (9) extending along the length of the positioning groove (8) in the positioning groove (8); the elastic movable contact piece (7) includes two connecting pieces (72) connected to the two ends of the two V-shaped contact portions (71), and a connecting groove (73) formed between the two V-shaped contact portions (71); when the elastic movable contact piece (7) is inserted into the positioning groove (8), the positioning boss passes into the connecting groove (73), so that the two connecting pieces (72) elastically abut against the two ends of the positioning boss to form a positioning fit.

10. A speed-regulating rotary switch according to claim 9, characterized in that: The positioning boss (9) and the positioning groove (8) are connected by a first gap (81) and a second gap (82) of different lengths. One of the connecting pieces (72) is limited in the first gap (81), and the other connecting piece (72) is disposed in the second gap (82) and can move when the elastic movable contact piece (7) is pressed. The positioning groove (8) is provided with a plurality of protruding ribs (83) that contact the bottom of the elastic movable contact piece (7) at intervals.

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