Dental handpiece

Abstract

A dental curved handpiece, relating to the field of oral treatment equipment, includes a head assembly, a housing, a connecting sleeve, a gearbox, a transmission sleeve, a drive shaft, an air tube, and a water tube. The housing is provided with spray holes; the head assembly is mounted on the head end of the housing; the connecting sleeve is provided with independent air and water channels; the connecting sleeve is inserted into the tail end of the housing; the transmission sleeve is installed inside the housing, and its interior is provided with a mixing channel communicating with the spray holes; the air channels are connected to the mixing channel via the air tube, and the water channels are connected to the mixing channel via the water tube; the drive shaft is rotatably inserted through the transmission sleeve; the gearbox is installed inside the housing and is connected to the head assembly via the drive shaft. This dental curved handpiece design, through optimized water and air channel structures, can reduce the size of the head assembly, expand the surgical field of view, and improve the convenience and flexibility of operation.

Description

Technical Field

[0001] This utility model relates to the field of oral treatment equipment, and more specifically, to a dental curved handpiece. Background Technology

[0002] In dental treatment, especially in root canal treatment and prosthodontics, the dental handpiece is a common and important tool. To improve patient comfort and ensure treatment accuracy, many dental handpieces are designed with water outlets and airflow systems to spray water mist into the oral cavity. The water mist has multiple functions, not only helping to cool and clean the treatment area but also reducing heat and friction generated during treatment, thus minimizing patient discomfort. Currently, many dental handpieces are designed with both water and air systems, delivering liquids (such as water or saline) and gas to two chambers within the handpiece head (i.e., the water chamber and the air chamber), respectively. However, current dental handpieces have certain shortcomings:

[0003] 1. Larger Handpiece Size: To achieve independent channels and mixing chambers for the water and air paths, the liquid and gas in the water and air paths typically flow separately into the water and air chambers within the handpiece, where they are then thoroughly mixed before being sprayed out. While this design ensures effective water mist, it also increases the overall height and size of the dental handpiece head.

[0004] 2. Affects the doctor's operation and observation line of sight: The increase in the size of the handpiece leads to a corresponding increase in the height and thickness of the handpiece, which affects the doctor's field of vision during treatment; the curved handpiece handpiece usually hinders the doctor's clear observation of the treatment area, especially when performing delicate operations, the increased handpiece size may make it difficult for the doctor to see the details of the treatment area. Utility Model Content

[0005] The purpose of this invention includes, for example, providing a dental curved handpiece that optimizes the water and air passage structure, reduces volume, expands the surgical field of view, and improves the convenience and flexibility of operation.

[0006] The embodiments of this utility model can be implemented as follows:

[0007] In a first aspect, this utility model provides a dental curved handpiece, comprising a head assembly, a housing, a connecting sleeve, a gearbox, a transmission sleeve, a transmission shaft, an air pipe, and a water pipe, wherein:

[0008] The outer casing is provided with spray holes; the head assembly is installed at the head end of the outer casing; the connecting sleeve is provided with independent air passages and water passages; the connecting sleeve is inserted into the tail end of the outer casing; the transmission sleeve is installed inside the outer casing; the transmission sleeve has a mixing channel communicating with the spray holes; the air passage is connected to the mixing channel through the air pipe; the water passage is connected to the mixing channel through the water pipe; the transmission shaft is rotatably inserted through the transmission sleeve; the gearbox is installed inside the outer casing; the gearbox is connected to the head assembly via the transmission shaft.

[0009] In an optional embodiment, the connecting sleeve includes an integral inner shell and an annular boss. The annular boss is sleeved on the outside of the inner shell. The inner shell is provided with two annular flow grooves and two first through holes. The two annular flow grooves are arranged at intervals in the axial direction of the inner shell, and the two first through holes are respectively connected to the two annular flow grooves.

[0010] Both the air passage and the water passage are disposed on the annular protrusion and are arranged at intervals in the circumferential direction of the annular protrusion. The two first through holes respectively connect the air passage and the water passage.

[0011] In an optional embodiment, the outer wall surface of the annular boss is sealed to the inner wall surface of the outer shell, and the outer wall surface of the inner shell and the inner wall surface of the outer shell are spaced apart to form a positioning channel. The positioning channel is located on the side of the annular boss near the head assembly. The air pipe and the water pipe are both inserted into the positioning channel.

[0012] In an optional embodiment, the gearbox includes a housing and a transmission unit, the transmission unit being installed inside the gearbox and being connected to the transmission shaft; a clearance channel is formed between the housing and the outer shell for the air pipe and the water pipe to pass through, and the clearance channel is connected to the positioning channel.

[0013] In an optional embodiment, the outer casing is provided with a first channel and a second channel communicating with the avoidance channel, the air pipe is connected to the mixing channel through the first channel, and the water pipe is connected to the mixing channel through the second channel.

[0014] In an optional embodiment, the outer shell includes a front shell and a rear shell connected together; the connecting sleeve is inserted into the rear shell, and the positioning channel is formed between the rear shell and the housing; the first channel and the second channel are disposed in the front shell, one end of the first channel and the second channel are both located on the end face of the front shell that is connected to the rear shell, and the other end of the first channel and the second channel are both located on the inner wall surface of the front shell.

[0015] In an optional embodiment, a first annular drainage groove is provided on the outer peripheral surface of the transmission sleeve, surrounding the axis of the transmission sleeve. A second through hole is provided on the bottom wall of the first annular drainage groove. The first annular drainage groove is connected to the first channel, and the second through hole is connected to the mixing channel.

[0016] In an optional embodiment, a second annular drainage groove is provided on the outer peripheral surface of the transmission sleeve, surrounding the axis of the transmission sleeve. A third through hole is provided on the bottom wall of the second annular drainage groove, the third through hole connecting to the mixing channel, and the second annular drainage groove connecting to the second channel.

[0017] In an optional embodiment, the outer peripheral surface of the transmission sleeve is provided with a third annular drainage groove surrounding the axis of the transmission sleeve, and a fourth through hole is provided on the bottom wall of the third annular drainage groove. The third annular drainage groove is connected to the mixing channel, and the fourth through hole is connected to the spray hole.

[0018] In an optional embodiment, a plurality of sealing rings are provided between the housing and the transmission sleeve, arranged at intervals along the axial direction of the transmission sleeve.

[0019] The beneficial effects of this utility model embodiment include, for example:

[0020] In summary, the dental curved handpiece provided in this embodiment has its positioning channel located inside the transmission sleeve. The positioning channel is moved rearward relative to the handpiece assembly, reducing the size of the handpiece assembly and minimizing obstruction of the surgical field, thus facilitating a wider surgical view and easier surgical operation. Simultaneously, the short distance between the air and water channels on the connecting sleeve and the mixing channel reduces the length of the water and air pipes required to connect them, saving materials and reducing manufacturing costs. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of a dental handpiece according to an embodiment of this application;

[0023] Figure 2 for Figure 1 A magnified view of a portion of point A in the middle;

[0024] Figure 3 for Figure 1 A magnified view of a portion of point B in the middle.

[0025] icon:

[0026] 001-Air pipe; 002-Water pipe; 100-Head assembly; 200-Outer shell; 210-Front shell; 211-Spray hole; 212-First channel; 213-Second channel; 220-Rear shell; 300-Connecting sleeve; 310-Inner shell; 311-Annular flow groove; 312-First through hole; 320-Annular boss; 321-Air passage; 322-Water passage; 400-Gearbox; 410-Box shell; 420-Transmission unit; 500-Transmission sleeve; 501-Mixing channel; 510-First annular drainage groove; 511-Second through hole; 520-Second annular drainage groove; 521-Third through hole; 530-Third annular drainage groove; 531-Fourth through hole; 600-Drive shaft; 700-First sealing ring; 701-Second sealing ring; 702-Third sealing ring; 703-Fourth sealing ring. Detailed Implementation

[0027] 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, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0029] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0030] In the description of this utility model, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product is usually placed during use, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0031] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0032] It should be noted that, where there is no conflict, the features in the embodiments of this utility model can be combined with each other.

[0033] In existing technology, the mixing chamber of a dental handpiece is designed within the head assembly 100. The head assembly 100 is large, obstructs the surgical field of view, and makes surgical operation inconvenient. Furthermore, water and air need to be guided from the tail end of the dental handpiece to the mixing chamber within the head assembly 100 using water pipe 002 and air pipe 001 respectively. The placement of water pipe 002 and air pipe 001 occupies internal space within the dental handpiece, increasing its size and cost.

[0034] In view of this, the designers have provided a dental curved handpiece that, by optimizing the structure of the water path, air path and mixing chamber, can reduce the volume of the handpiece assembly by 100, expand the surgical field of view and reduce the manufacturing cost.

[0035] Please refer to Figures 1-3 This embodiment provides a dental curved handpiece, including a head assembly 100, a housing 200, a connecting sleeve 300, a gearbox 400, a transmission sleeve 500, a transmission shaft 600, an air pipe 001, and a water pipe 002. Specifically: the housing 200 is provided with a spray hole 211; the head assembly 100 is mounted on the head end of the housing 200; the connecting sleeve 300 is provided with independent air passages 321 and water passages 322, and is inserted into the tail end of the housing 200. The connecting sleeve 300 and the housing 200 cooperate to form a positioning channel 001, and both the air passages 321 and the water passages 322 are connected to the positioning channel 001; the gearbox 400 is mounted inside the housing 200 and is drive-connected to the head assembly 100. The gearbox 400 and the housing 200 cooperate to form a transfer channel, which simultaneously connects the spray hole 211 and the positioning channel 001.

[0036] As described above, the working principle of the dental handpiece provided in this embodiment is as follows:

[0037] The motor is plugged into the tail end of the connecting sleeve 300. The air and water passages integrated on the motor are connected to the air passage 321 and water passage 322 on the connecting sleeve 300, respectively. Water and air are input from the air passage 321 and water passage 322, respectively. The water and air enter together into the air pipe 001 and water pipe 002 installed in the positioning channel 001. The gas and liquid are transported to the mixing channel 501 on the transmission sleeve 500 through the air pipe 001 and water pipe 002, and finally sprayed out from the spray hole 211, thus entering the oral cavity for oral cleaning and other operations.

[0038] It should be understood that by placing the mixing channel 501 inside the transmission sleeve 500, the mixing channel 501 is moved rearward relative to the head assembly 100, reducing the volume of the head assembly 100. This results in less obstruction of the surgical field by the head assembly 100, facilitating a wider surgical field and easier surgical procedures. Simultaneously, the shorter distance between the airway 321 and waterway 322 on the connecting sleeve 300 and the mixing channel 501 reduces the length of the water pipe 002 connecting the waterway 322 and the mixing channel 501, as well as the air pipe 001 connecting the airway 321 and the mixing channel 501, thus saving on manufacturing costs.

[0039] The following embodiments illustrate the detailed structure of the dental curved handpiece of this application by way of example.

[0040] In this embodiment, optionally, the dental curved handpiece includes a head assembly 100, a housing 200, a connecting sleeve 300, a gearbox 400, a transmission sleeve 500, a transmission shaft 600, an air tube 001, and a water tube 002. The head assembly 100 is installed at the head end of the housing 200, and the connecting sleeve 300 is inserted into the tail end of the housing 200. The gearbox 400, transmission sleeve 500, transmission shaft 600, air tube 001, and water tube 002 are all installed inside the housing 200. The transmission shaft 600 passes through the transmission sleeve 500, and the two are rotatably connected. The gearbox 400 is connected to the head assembly 100 via the transmission shaft 600. The head assembly 100 is used to install the working tip.

[0041] In this embodiment, optionally, the outer shell 200 is configured as a split structure, with each split part processed separately, and then multiple split parts are assembled together, reducing processing difficulty and saving processing and manufacturing costs. For example, the outer shell 200 includes a front shell 210 and a rear shell 220. The tail end of the front shell 210 is sealed to the front end of the rear shell 220, and the two can be fixedly connected by means of snap-fit, threaded structure, adhesive or welding. The front shell 210 and the front end are connected to the head assembly 100. A spray hole 211 is provided on the peripheral wall of the front shell 210. The axis of the spray hole 211 is designed at an acute angle to the axis of the front shell 210, so that the water mist sprayed from the spray hole 211 moves towards the head assembly 100. In other words, the spray hole 211 has a first port located inside the front housing 210 and a second port located outside the front housing 210. Water mist enters from the first port and exits from the second port. The first port is closer to the tail end of the front housing 210 than the second port, that is, the second port is closer to the head assembly 100 than the first port. Water mist can be sprayed out from the second port and move toward the head assembly 100, making it easier to enter the mouth.

[0042] Meanwhile, the front housing 210 is provided with a first channel 212 and a second channel 213. The ends of both channels 212 and 213 near the rear housing 220 extend to the end face of the front housing 210 near the rear housing 220. The other ends of both channels 212 and 213 are bent inwards and located on the inner wall surface of the front housing 210. This inner wall surface forms an assembly hole for the insertion of the transmission sleeve 500. The ends of both channels 212 and 213 away from the rear housing 220 can connect to the mixing channel 501 on the transmission sleeve 500. An air pipe 001 is inserted into the first channel 212, and a water pipe 002 is inserted into the second channel 213. In this way, both ends of the air pipe 001 and the water pipe 002 are positioned by being inserted into their corresponding channels, ensuring a secure position that prevents loosening and leakage. Furthermore, the axes of the front shell 210 and the rear shell 220 can be designed at a non-zero angle, making the outer shell 200 approximately curved. This facilitates the movement of the operating head assembly 100 within the oral cavity and provides a better field of vision during surgery. Please refer to [reference needed]. Figures 1-3 In this embodiment, optionally, the connecting sleeve 300 includes an integral inner shell 310 and an annular boss 320. The annular boss 320 is sleeved on the outside of the inner shell 310, and the front end of the annular boss 320 is spaced from the front end of the inner shell 310, that is, the front end of the inner shell 310 extends beyond the front end of the annular boss 320. Two annular flow grooves 311 are provided on the inner circumferential surface of the inner shell 310. The two annular flow grooves 311 are arranged at intervals in the axial direction of the inner shell 310 and are independent of each other. Two first through holes 312 are provided on the peripheral wall of the inner shell 310, and the two first through holes 312 are respectively connected to the two annular flow grooves 311. At the same time, an air passage 321 and a water passage 322 are provided on the end face where the front end of the annular boss 320 is located. The air passage 321 and the water passage 322 are arranged at intervals in the circumferential direction of the annular boss 320, and the two first through holes 312 are respectively connected to the air passage 321 and the water passage 322.

[0043] When the motor is plugged into the tail end of the inner shell 310, the water passage and air passage on the motor are respectively connected to two annular flow grooves 311, thereby connecting the air passage 321 or the water passage 322 through the first through hole 312 on the corresponding annular flow groove 311.

[0044] Furthermore, the inner shell 310 and the annular boss 320 are inserted together into the rear shell 220. The front end of the inner shell 310 is inserted from the rear end of the rear shell 220. The inner shell 310 is located on the side of the annular boss 320 closer to the front shell 210. The outer circumferential surface of the annular boss 320 is sealed to the inner circumferential surface of the rear shell 220 to prevent water and air leakage. The outer diameter of the inner shell 310 is smaller than the inner diameter of the rear shell 220. There is a gap between the outer circumferential surface of the inner shell 310 and the inner circumferential surface of the rear shell 220 to form an annular positioning channel 001. The water channel 322 and the air channel 321, located on the front end side of the annular boss 320, directly connect to the positioning channel 001. By utilizing the rear shell 220 and the inner shell 310 to form the positioning channel 001, there is no need to drill holes in the rear shell 220, reducing the thickness of the rear shell 220. This results in a smaller radial dimension of the overall structure of the dental handpiece, a compact overall structure, and a small volume, which is beneficial for miniaturization and lightweight design.

[0045] Meanwhile, one end of the trachea 001 is inserted into the airway 321, and one end of the water pipe 002 is inserted into the waterway 322. Both the trachea 001 and the water pipe 002 are located in the positioning channel. The trachea 001 and the water pipe 002 are firmly positioned and not easy to loosen. The positioning channel is used in a reasonable way, which makes the overall structure compact and small in size.

[0046] In this embodiment, optionally, the gearbox 400 includes a housing 410 and a transmission unit 420, the transmission unit 420 being a gear transmission assembly. The housing 410 is fixed within the rear housing 220, and a portion of the outer wall surface of the housing 410 has a gap with the inner wall surface of the rear housing 220 to form two clearance channels 002. One end of each clearance channel is connected to a positioning channel. The air pipe 001 and the water pipe 002 are respectively inserted into the two clearance channels 002. The air pipe 001 and the water pipe 002 are positioned stably by the cooperation of the rear housing 220, the connecting sleeve 300, and the housing 410.

[0047] Optionally, the transmission sleeve 500 is configured as a hollow structure, with the transmission shaft 600 passing through it. A bearing is installed between the two, allowing the transmission shaft 600 to rotate more flexibly relative to the transmission sleeve 500. Simultaneously, a mixing channel 501 is provided inside the peripheral wall of the transmission sleeve 500. One end of the mixing channel 501 is closed, and the other end is open. The open end of the mixing channel 501 is located on an annular end face of the transmission sleeve 500, serving as a process opening to facilitate the machining of the mixing channel 501. To prevent leakage at the open end, a plug can be used for sealing. The outer peripheral wall of the transmission sleeve 500 has a first annular drainage groove 510, a second annular drainage groove 520, and a third annular drainage groove 530. These three grooves all surround the axis of the transmission sleeve 500, and are arranged sequentially and independently along the extension direction of the axis of the transmission sleeve 500. The first annular drainage channel 510 has a second through hole 511 on its bottom wall, the second annular drainage channel 520 has a third through hole 521 on its bottom wall, and the third annular drainage channel 530 has a fourth through hole 531 on its bottom wall. Both the second through hole 511 and the third through hole 521 are connected to the mixing channel 501, which in turn is connected to the third annular drainage channel 530.

[0048] During assembly, the transmission sleeve 500 is fixed in the front housing 210, the first annular drainage groove 510 is located near the rear housing 220, and correspondingly, the third annular drainage groove 530 is located near the head assembly 100. The transmission shaft 600 is rotatably mounted in the mounting hole of the transmission sleeve 500, with the proximal end of the transmission shaft 600 connected to the head assembly 100 and the distal end of the transmission shaft 600 connected to the transmission unit 420. Meanwhile, the port of the first channel 212 extending to the inner wall of the front shell 210 is connected to the first annular drainage groove 510, and the first annular drainage groove 510 is connected to the mixing channel 501 through the second through hole 511; the port of the second channel 213 extending to the inner wall of the front shell 210 is connected to the second annular drainage groove 520, and the second annular drainage groove 520 is connected to the mixing channel 501 through the third through hole 521. The mixing channel 501 is connected to the third annular drainage groove 530, and the third annular drainage groove 530 is connected to the spray hole 211 through the fourth through hole 531. In this way, the gas input through the air pipe 001 can enter the first annular drainage groove 510 through the first channel 212, and then enter the mixing channel 501 through the second through hole 511; simultaneously, the liquid input through the water pipe 002 can enter the second annular drainage groove 520 through the second channel 213, and then enter the mixing channel 501 through the third through hole 521. The gas and liquid mix in the mixing channel 501, flow into the third annular drainage groove 530, and enter the spray hole 211 through the fourth through hole 531, and finally be sprayed out. Since the mixing channel 501 is located inside the transmission sleeve 500, the internal space of the transmission sleeve 500 is utilized in a reasonable way, eliminating the need to set up channels on the front shell 210 and the need to increase the wall thickness of the front shell 210, thereby reducing the volume of the front shell 210.

[0049] Meanwhile, to improve sealing, a first sealing ring 700, a second sealing ring 701, a third sealing ring 702, and a fourth sealing ring 703 are arranged sequentially along the axial direction of the transmission sleeve 500 between the transmission sleeve 500 and the front housing 210. A first annular drainage groove 510 is located between the first sealing ring 700 and the second sealing ring 701, a second annular drainage groove 520 is located between the second sealing ring 701 and the third sealing ring 702, and a third annular drainage groove 530 is located between the third sealing ring 702 and the fourth sealing ring 703. This design allows water to enter from the first channel 212. The gas in the first annular drainage groove 510 is blocked by the first sealing ring 700 and the second sealing ring 701, preventing leakage from both sides of the first annular drainage groove 510; the liquid entering the second annular drainage groove 520 from the second channel 213 is blocked by the second sealing ring 701 and the third sealing ring 702, preventing leakage from both sides of the second annular drainage groove 520; the water mist flowing from the third annular drainage groove 530 to the spray hole 211 is blocked by the third sealing ring 702 and the fourth sealing ring 703, preventing leakage from both sides of the third annular drainage groove 530. This ensures good sealing and stable and reliable operation.

[0050] In this embodiment, it should be noted that the head assembly 100 can refer to existing known structures. No improvement has been made to its principle in this embodiment. In order to avoid repetition and redundancy, it will not be described in detail.

[0051] In this embodiment, it should be noted that the dental curved handpiece has a front end and a rear end. The front end is the end that is inserted into the oral cavity during use, and the rear end is the end that is closer to the operator during use. Unless otherwise specified, the positions of the front and rear ends of other components of the dental curved handpiece are based on this.

[0052] The dental handpiece provided in this embodiment works as follows:

[0053] Gas and liquid are input from airway 321 and waterway 322 respectively, and transported through air pipe 001 and water pipe 002 respectively. They enter the mixing channel 501 for mixing, and after mixing, they are sprayed out from spray hole 211 and enter the oral cavity.

[0054] The dental curved handpiece provided in this embodiment has its mixing channel 501 located within the transmission sleeve 500, positioned rearward relative to the handpiece assembly 100. This reduces the size of the handpiece assembly 100, expands the surgical field of view, and facilitates surgical operations. Furthermore, the efficient use of internal space to arrange structures such as the air tube 001 and water tube 002 reduces the thickness of the outer shell 200, resulting in a smaller outer shell size and facilitating the miniaturization and lightweight design of the dental curved handpiece.

[0055] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A dental handpiece characterized by, Includes a head assembly (100), a housing (200), a connecting sleeve (300), a gearbox (400), a transmission sleeve (500), a transmission shaft (600), an air pipe (001), and a water pipe (002), wherein: The outer casing (200) is provided with a spray hole (211); the head assembly (100) is installed at the head end of the outer casing (200); the connecting sleeve (300) is provided with independent air passages (321) and water passages (322); the connecting sleeve (300) is inserted into the tail end of the outer casing (200); the transmission sleeve (500) is installed inside the outer casing (200); the interior of the transmission sleeve (500) is provided with a mixing channel communicating with the spray hole (211). (501), the air passage (321) is connected to the mixing channel (501) through the air pipe (001), and the water passage (322) is connected to the mixing channel (501) through the water pipe (002); the drive shaft (600) is rotatably inserted into the drive sleeve (500); the gearbox (400) is installed in the housing (200), and the gearbox (400) is connected to the head assembly (100) through the drive shaft (600).

2. The dental handpiece according to claim 1, characterized in that: The connecting sleeve (300) includes an integral inner shell (310) and an annular boss (320). The annular boss (320) is sleeved on the outer side of the inner shell (310). The inner shell (310) is provided with two annular flow grooves (311) and two first through holes (312). The two annular flow grooves (311) are arranged at intervals in the axial direction of the inner shell (310). The two first through holes (312) are respectively connected to the two annular flow grooves (311). The air passage (321) and the water passage (322) are both provided on the annular boss (320) and are arranged at intervals in the circumferential direction of the annular boss (320). The two first through holes (312) respectively connect the air passage (321) and the water passage (322).

3. The dental handpiece according to claim 2, characterized in that: The outer wall of the annular boss (320) is sealed to the inner wall of the outer shell (200). The outer wall of the inner shell (310) and the inner wall of the outer shell (200) are spaced apart to form a positioning channel. The positioning channel is located on the side of the annular boss (320) near the head assembly (100). The air pipe (001) and the water pipe (002) are both inserted into the positioning channel.

4. The dental handpiece according to claim 3, characterized in that: The gearbox (400) includes a housing (410) and a transmission unit (420). The transmission unit (420) is installed inside the gearbox (400) and is connected to the transmission shaft (600). A clearance channel is formed between the housing (410) and the outer shell (200) for the air pipe (001) and the water pipe (002) to pass through. The clearance channel is connected to the positioning channel.

5. The dental handpiece according to claim 4, characterized in that: The outer casing (200) is provided with a first channel (212) and a second channel (213) that communicate with the avoidance channel. The air pipe (001) is connected to the mixing channel (501) through the first channel (212), and the water pipe (002) is connected to the mixing channel (501) through the second channel (213).

6. The dental handpiece according to claim 5, characterized in that: The outer shell (200) includes a front shell (210) and a rear shell (220) connected together; the connecting sleeve (300) is inserted into the rear shell (220), and the positioning channel is formed between the rear shell (220) and the housing (410); the first channel (212) and the second channel (213) are disposed in the front shell (210), one end of the first channel (212) and the second channel (213) are both located on the end face of the front shell (210) connected to the rear shell (220), and the other end of both are located on the inner wall surface of the front shell (210).

7. The dental handpiece according to claim 6, characterized in that: The outer circumferential surface of the transmission sleeve (500) is provided with a first annular drainage groove (510) surrounding the axis of the transmission sleeve (500). A second through hole (511) is provided on the bottom wall of the first annular drainage groove (510). The first annular drainage groove (510) is connected to the first channel (212), and the second through hole (511) is connected to the mixing channel (501).

8. The dental handpiece according to claim 6, characterized in that: The outer circumferential surface of the transmission sleeve (500) is provided with a second annular drainage groove (520) surrounding the axis of the transmission sleeve (500). A third through hole (521) is provided on the bottom wall of the second annular drainage groove (520). The third through hole (521) is connected to the mixing channel (501), and the second annular drainage groove (520) is connected to the second channel (213).

9. The dental handpiece according to any one of claims 1-8, characterized in that: The outer circumferential surface of the transmission sleeve (500) is provided with a third annular drainage groove (530) surrounding the axis of the transmission sleeve (500). A fourth through hole (531) is provided on the bottom wall of the third annular drainage groove (530). The third annular drainage groove (530) is connected to the mixing channel (501), and the fourth through hole (531) is connected to the spray hole (211).

10. The dental handpiece according to any one of claims 1-8, characterized in that: A plurality of sealing rings are provided between the outer casing (200) and the transmission sleeve (500), which are spaced apart in the axial direction of the transmission sleeve (500).

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