Dental handpiece speed increasing contra angle machine

Abstract

The present invention discloses a dental handpiece speed increasing bending machine, including a handpiece, a first transmission shaft and a second transmission shaft, one end of the first transmission shaft is connected to the handpiece, and the other end is transmission-connected to the second transmission shaft, the first transmission shaft and the second transmission shaft have an angle, a needle is installed in the handpiece, the outer periphery of the needle is sleeved with a first gear, the end of the first transmission shaft connected to the handpiece is provided with a second gear, the second gear meshes with the first gear, the first gear and the second gear have an angle, and the second gear can at least eliminate part of the axial thrust generated on the first gear. The present invention partially eliminates or even completely eliminates the axial force of the gear sleeved outside the needle by changing the gear matching structure, greatly reduces the friction between the bearings, and increases the service life of the bearings; at the same time, it greatly reduces the generation of heat, thereby reducing the amount of cooling water used during the operation, and providing the doctor with a highly clear operating space.

Description

Technical Field

[0001] The invention relates to the field of medical equipment, and in particular to a dental handpiece speed increasing bending machine. Background Art

[0002] Dental handpieces are divided into high-speed dental handpieces and low-speed dental handpieces. The speed of high-speed dental handpieces reaches 350,000-420,000 revolutions per minute, and is mainly used for treatment and restoration such as drilling and cutting; while low-speed dental handpieces are mainly used for drilling, grinding and cutting treatments. Low-speed handpieces are divided into straight and curved. Straight handpieces are used for grinding and polishing, and are mainly used for extraoral treatment, while curved handpieces are mainly used for intraoral treatment.

[0003] As shown in the Chinese utility model patent with patent number 201620241116.9, a speed-increasing dental handpiece is disclosed, including a handpiece 1, a first transmission shaft 2, a second transmission shaft 3 and a transition shaft 4, one end of the first transmission shaft 2 is connected to the handpiece 1, one end of the transition shaft 4 is transmission-connected to the first transmission shaft 2, and the other end of the transition shaft 4 is transmission-connected to the second transmission shaft 3, and the first transmission shaft 2 and the second transmission shaft 3 have an angle. The dental handpiece uses the transition shaft 4 to connect the two transmission shafts, which can effectively decompose the transmission action of the two transmission shafts, thereby reducing the loss of the transmission end and the material requirements, thereby greatly increasing the service life of the speed-increasing dental handpiece and reducing the cost.

[0004] However, the above dental handpieces, like all contra-angle machines currently on the market, have the following disadvantages: Figures 1 to 4 As shown, in order to achieve a transmission connection with a certain angle (90° and above), the gear at one end of the first transmission shaft 2 connected to the handpiece 1 (hereinafter referred to as gear B) must be a bevel gear, and the gear (hereinafter referred to as gear C) that matches gear B and is sleeved outside the needle must also be a bevel gear. When gear B rotates, two forces will be generated on gear C, one is the radial thrust that drives gear C to rotate, and the other is the axial thrust that pushes gear C to move toward the rear cover of the handpiece 1. Bearings are precision parts of turbine handpieces and are consumable parts. If they are worn or otherwise damaged, they can easily cause damage to the handpiece. Due to the existence of this axial thrust, when the dental handpiece is working, the needle will generate axial force, which will cause friction between the bearings sleeved on the outer periphery of the needle, seriously affecting the service life of the bearings. Summary of the invention

[0005] The object of the present invention is to provide a dental handpiece speed increasing bending machine with a long service life and less heat generation, which can at least solve one of the above problems.

[0006] According to one aspect of the present invention, a dental handpiece speed increasing bending machine is provided, comprising a handpiece, a first transmission shaft and a second transmission shaft, wherein one end of the first transmission shaft is connected to the handpiece, and the other end is transmission-connected to the second transmission shaft, and the first transmission shaft and the second transmission shaft have an included angle, a needle is installed in the handpiece, and a bearing and a first gear are mounted on the outer periphery of the needle, and a second gear is provided at one end of the first transmission shaft connected to the handpiece, and the second gear is meshed with the first gear, and an angle is formed between the first gear and the second gear, and the second gear can at least eliminate part of the axial thrust generated on the first gear.

[0007] The conventional first gear and the second gear are standard bevel gears meshing, which will form a radial and axial force on the conical surface, and this axial force will cause the bearing to heat up a lot. The present invention partially or even completely eliminates the axial force of the gear sleeved outside the needle by changing the conventional gear matching structure, greatly reducing the friction between the bearings and increasing the service life of the bearings;

[0008] At the same time, due to the large amount of heat released by the friction between the bearings, the temperature of the entire handpiece will accelerate, affecting normal use. Since the contra-oral machine is mainly used for intraoral treatment, during surgery, the contra-oral machine head works directly in the human mouth. If the temperature is too high, it will definitely not be able to meet the use requirements. The existing solution to this problem is to use physical cooling methods such as an external cooling water pipe to take away the heat from the handpiece to reduce the temperature. However, the cooling water after use will remain directly in the human mouth. If the mobile phone needs to be used for a long time during the operation, it is necessary to continuously use cooling water to cool it down. The large amount of water used will cause the operating surface to become blurred, affecting the doctor's operation; at the same time, it is necessary to continuously extract water from the mouth to meet normal surgery, which seriously affects the patient's treatment experience.

[0009] The present invention partially or completely eliminates the axial force of the gear sleeved outside the needle by changing the gear matching structure, greatly reduces the friction between the bearings, and increases the service life of the bearings; at the same time, it greatly reduces the generation of heat, thereby reducing the amount of cooling water used during the operation, and providing the doctor with a highly clear operating space.

[0010] In some embodiments, the first gear is a spur gear or a bevel gear. Therefore, when the first gear is a spur gear, the force exerted by the second gear on the first gear is perpendicular to the outer wall of the first gear, that is, the force is only a lateral thrust, which is completely used to drive the first gear to rotate, and no axial thrust is generated, which completely eliminates the axial force of the gear sleeved outside the needle. When the first gear is a bevel gear, the force exerted by the second gear on the first gear is almost perpendicular to the outer wall of the first gear, so a small amount of axial thrust will be generated when it just contacts, but almost no axial thrust will be generated during the rotation process, which eliminates most of the axial force of the gear sleeved outside the needle.

[0011] In some embodiments, one end of the second gear is provided with an opening that matches the first transmission shaft, and the other end is provided with a plurality of wedge-shaped teeth distributed in a circumferential array and diverging outward, and the wedge-shaped teeth gradually become sharper from the root to the top. Therefore, when the first transmission shaft drives the second gear to rotate, the top of the wedge-shaped teeth acts vertically on the tooth surface of the first gear. Since the first gear is a spur gear, the force of the wedge-shaped teeth acting on the first gear only generates radial thrust, and no axial thrust is generated.

[0012] In some embodiments, the wedge-shaped tooth is formed by enclosing three curved surfaces, namely, a first curved surface, a second curved surface, and a third curved surface, the first curved surface, the second curved surface, and the third curved surface are connected to each other, the first curved surface is enclosed by three segments of lines, namely, a first line, a second line, and a third line, the second curved surface is enclosed by three segments of lines, namely, a first line, a third line, and a fourth line, the first curved surface and the second curved surface intersect at the first line, the first curved surface and the second curved surface are symmetrical along the plane where the first line is located, and the first line, the second line, the third line, the fourth line, and the fifth line are all arcs convex outwards. Thus, the special shape of the wedge-shaped tooth can ensure that only radial force is generated when it contacts the first gear during rotation.

[0013] In some embodiments, an opening that matches the first transmission shaft is formed at one end of the second gear, and a plurality of wedge-shaped teeth distributed in a circular array are formed at the other end, wherein the wedge-shaped teeth gradually become sharper from the root to the top.

[0014] In some embodiments, the wedge-shaped tooth is formed by three curved surfaces: a first curved surface, a second curved surface, and a third curved surface. The first curved surface, the second curved surface, and the third curved surface are connected to each other. The first curved surface is formed by three segments of lines: a first line, a second line, and a third line. The second curved surface is formed by three segments of lines: a first line, a fourth line, and a fifth line. The first curved surface and the second curved surface intersect at the first line. The first curved surface and the second curved surface are symmetrically arranged along the plane where the first line is located. The first line, the second line, and the fourth line are all arcs convex outward, and the third line and the fifth line are straight lines.

[0015] In some embodiments, the dental handpiece speed increasing bending machine further includes a transition shaft, one end of the transition shaft is connected to the first transmission shaft, the other end of the transition shaft is connected to the second transmission shaft, the end of the first transmission shaft is provided with a third gear, the second transmission shaft is provided with a fourth gear, and the two ends of the transition shaft are provided with a fifth gear and a sixth gear, respectively, the third gear is meshed with the fifth gear, and the fourth gear is meshed with the sixth gear. Thus, the use of a transition shaft to connect the two transmission shafts can effectively decompose the transmission action of the two transmission shafts, thereby reducing the loss of the transmission end and the requirements for materials; by using gear transmission, the two sets of gears can each have a larger contact area, reducing the torque acting on the teeth, thereby reducing the wear of the gears and increasing the service life.

[0016] In some embodiments, the third gear and the fifth gear are both bevel gears, the fourth gear is an internal gear, and the sixth gear is a spur gear. Thus, the third gear and the fifth gear are externally meshed, and the fourth gear and the sixth gear are internally meshed, and the teeth can be closely meshed to achieve pure rolling transmission, effectively reducing gear wear and increasing service life.

[0017] In some embodiments, the dental handpiece speed increasing bending machine also includes a first shell, an elbow and a second shell connected in sequence, the first shell is connected to the handpiece, and the first transmission shaft, the second transmission shaft and the transition shaft are all located in the space formed by the first shell, the elbow and the second shell.

[0018] In some embodiments, a support block is provided in the head, and the transition shaft is supported by the support block. Thus, the support block can ensure the stable installation of the transition shaft in the dental handpiece.

[0019] Beneficial effects of the present invention:

[0020] The present invention partially or completely eliminates the axial force of the gear sleeved outside the needle by changing the gear matching structure, greatly reduces the friction between the bearings, and improves the service life of the bearings; at the same time, it greatly reduces the generation of heat, thereby reducing the amount of cooling water used during the operation, and providing the doctor with a highly clear operating space. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of a dental handpiece speed increasing bending machine in the prior art;

[0022] Figure 2 for Figure 1 A schematic cross-sectional view of the gear transmission structure in which gear B and gear C cooperate;

[0023] Figure 3 for Figure 1 A schematic diagram of the structure of the gear C of the gear transmission structure shown;

[0024] Figure 4 for Figure 1 A schematic diagram of the structure of gear B of the gear transmission structure shown;

[0025] Figure 5 It is a schematic diagram of the three-dimensional structure of the dental handpiece speed increasing bending machine shown in Example 1;

[0026] Figure 6 for Figure 5 The schematic cross-sectional structure diagram of the dental handpiece speed increasing contra-angle machine shown;

[0027] Figure 7 for Figure 6 The enlarged structural diagram of the dental handpiece speed increasing bending machine at A is shown;

[0028] Figure 8 for Figure 6 The enlarged structural diagram of the dental handpiece speed increasing bending machine at B is shown;

[0029] Fig. 9 for Figure 5 A schematic diagram of the three-dimensional structure of the first gear and the second gear of the dental handpiece speed increasing bending machine;

[0030] Fig.10 for Fig. 9 A schematic cross-sectional structure diagram of the first gear and the second gear shown;

[0031] Fig.11 for Figure 5 A schematic diagram of the three-dimensional structure of the second gear of the dental handpiece speed increasing bending machine shown;

[0032] Fig.12 for Fig.11 A schematic diagram of the top view of the second gear shown;

[0033] Fig.13 It is a schematic diagram of the three-dimensional structure of the dental handpiece speed increasing bending machine shown in Example 2;

[0034] Fig.14 for Fig.13 The schematic cross-sectional structure diagram of the dental handpiece speed increasing contra-angle machine shown;

[0035] Fig.15 for Fig.13 The enlarged structural diagram of the dental handpiece speed increasing bending machine at C is shown;

[0036] Fig.16 for Fig.13 A schematic diagram of the three-dimensional structure of the first gear and the second gear of the dental handpiece speed increasing bending machine;

[0037] Fig.17 for Fig.16 A schematic diagram of a top view of the structure of the first gear and the second gear matching each other;

[0038] Fig.18 for Fig.16 A schematic diagram of the three-dimensional structure of the second gear shown;

[0039] Fig.19 for Fig.18 Schematic diagram of the top view of the structure of the second gear shown.

[0040] Figures 5 to 19The figure marks in it are: 1-machine head; 2-first transmission shaft; 3-second transmission shaft; 4-transition shaft; 5-needle; 6-first gear; 7-second gear; 8-first housing; 9-elbow; 10-second housing; 11-cooling water pipe; 12-bearing; 21-third gear; 31-fourth gear; 41-fifth gear; 42-sixth gear; 71-opening; 72-wedge-shaped tooth; 91-support block; 721-first curved surface; 722-second curved surface; 723-third curved surface; a-first line; b-second line; c-third line; d-fourth line; e-fifth line. DETAILED DESCRIPTION

[0041] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0042] Example 1

[0043] Figures 5 to 12 A dental handpiece speed increasing bending machine according to an embodiment of the present invention is schematically shown.

[0044] like Figures 5 to 12 As shown, the dental handpiece speed increasing bending machine comprises a handpiece 1, a first transmission shaft 2 and a second transmission shaft 3. One end of the first transmission shaft 2 is connected to the handpiece 1, and the other end is transmission-connected to the second transmission shaft 3. The first transmission shaft 2 and the second transmission shaft 3 have an angle to form an elbow 9 of the dental handpiece. A needle 5 is installed in the handpiece 1, and bearings 12 are sleeved on the outer peripheries of both ends of the part of the needle 5 located in the handpiece 1. The provision of the bearing 12 realizes the rotatable installation of the needle 5. A first gear 6 is fixedly sleeved on the outer periphery of the middle position of the part of the needle 5 located in the handpiece 1, and a second gear 7 is fixedly sleeved on one end of the first transmission shaft 2 connected to the handpiece 1. The second gear 7 meshes with the first gear 6. There is an angle between the first gear 6 and the second gear 7. In this embodiment, the angle between the straight line in the radial direction of the first gear 6 and the straight line in the radial direction of the second gear 7 is approximately 120°. The second gear 7 can at least eliminate part of the axial thrust generated on the first gear 6.

[0045] The first gear 6 may be a spur gear or a bevel gear.

[0046] As shown in the figure, the first gear 6 of this embodiment is a spur gear and the number of teeth of the first gear 6 is 19. Therefore, when the first gear 6 is a spur gear, the force exerted by the second gear 7 on the first gear 6 is perpendicular to the outer wall of the first gear 6, that is, the force is only a radial thrust, which is completely used to drive the first gear 6 to rotate, and no axial thrust is generated.

[0047] One end of the second gear 7 is provided with an opening 71 that matches the second transmission member, and the other end is provided with a plurality of wedge-shaped teeth 72 that are distributed in a circumferential array and diverge outward. Fig.11As shown, the diameter of the circle where the outer wall of the wedge-shaped teeth 72 is located gradually increases from bottom to top. The wedge-shaped teeth 72 gradually become sharper from the root to the top. The number of the wedge-shaped teeth 72 of the second gear 7 in this embodiment is 13. Therefore, when the second transmission member drives the second gear 7 to rotate, the top of the wedge-shaped teeth 72 acts vertically on the tooth surface of the first gear 6. Since the first gear 6 is a spur gear, the force of the wedge-shaped teeth 72 acting on the first gear 6 only generates radial thrust, and no axial thrust is generated.

[0048] like Figure 7 As shown, each wedge-shaped tooth 72 is formed by three curved surfaces, namely, a first curved surface 721, a second curved surface 722 and a third curved surface 723, and a bottom surface. The first curved surface 721, the second curved surface 722 and the third curved surface 723 are connected to each other. The first curved surface 721 is formed by three segments of lines, namely, a first line a, a second line b and a third line c, which are connected in sequence. The second curved surface 722 is formed by three segments of lines, namely, a first line a, a fourth line d and a fifth line e, which are connected in sequence. The third curved surface 723 is formed by the second line b and the fourth line d, and the third curved surface 723 is connected to the outer wall of the second gear 7 as a whole. The first curved surface 721 and the second curved surface 722 intersect at the first line a, and the first curved surface 721 and the second curved surface 722 are symmetrically arranged along the plane where the first line a is located. The first line a, the second line b, the third line c, the fourth line d and the fifth line e of this embodiment are all arcs convex outward. As shown Figure 5 As shown, when the first gear 6 is meshed with the second gear 7, the hypotenuse of the cross section of the topmost wedge-shaped tooth 72 of the second gear 7 is parallel to the horizontal line in the radial direction of the first gear 6. Therefore, the special shape of the wedge-shaped tooth 72 can ensure that only radial force is generated when contacting the first gear 6 during rotation.

[0049] like Figure 6 and Figure 8 As shown, one end of the transition shaft 4 is transmission-connected to the first transmission shaft 2, and the other end of the transition shaft 4 is transmission-connected to the second transmission shaft 3. The first transmission shaft 2 and the second transmission shaft 3 have an angle to form an elbow of the speed-increasing dental mobile phone.

[0050] A third gear 21 is provided at the end of the first transmission shaft 2, a fourth gear 31 is provided at the second transmission shaft 3, a fifth gear 41 and a sixth gear 42 are provided at both ends of the transition shaft 4, the third gear 21 meshes with the fifth gear 41, and the fourth gear 31 meshes with the sixth gear 42.

[0051] The third gear 21 and the fifth gear 41 are both bevel gears. Therefore, the two gears make the first transmission shaft 2 and the transition shaft 4 form a bend angle, and the two gears can be tightly meshed during transmission. The fourth gear 31 is an internal gear, and the sixth gear 42 is a spur gear. During transmission, the two gears can be tightly meshed. The two sets of gear pair transmission decompose the transmission action of the first transmission shaft 2 and the second transmission shaft 3, so that the gears perform pure rolling transmission, which greatly reduces gear wear and makes the transmission process smoother.

[0052] The speed increasing dental handpiece of this embodiment further comprises a first housing 5, an elbow 6 and a second housing 7 connected in sequence, the first housing 5 is connected to the handpiece 1, the first transmission shaft 2, the second transmission shaft 3 and the transition shaft 4 are all located in the space formed by the first housing 5, the elbow 6 and the second housing 7. A support block 61 is provided in the elbow 6, and the transition shaft 4 is supported by the support block 61. Bearings are sleeved at both ends of the transition shaft 4, and the bearings are supported by the support block 61, so that the transition shaft 4 can be rotatably installed.

[0053] The outer circumferences of the first transmission shaft 2, the second transmission shaft 3 and the transition shaft 4 are all sleeved with corresponding bearings to ensure smooth rotation of each component.

[0054] In addition, a cooling water pipe 11 is fixedly provided on the outer shell of the handpiece 1 of the present embodiment. The cooling water pipe 11 is externally connected to cooling water to take away the heat generated by the handpiece 1 .

[0055] The working process of the dental handpiece speed increasing bending machine of this embodiment is as follows:

[0056] The second transmission shaft 3 rotates under the drive of external power, driving the fourth gear 31 connected thereto to rotate, and the fourth gear 31 drives the sixth gear 42 to rotate, driving the transition shaft 4 to rotate, and the fifth gear 41 also rotates accordingly. The fifth gear 41 drives the third gear 21 sleeved on one end of the first transmission shaft 2 to rotate, driving the first transmission shaft 2 and the second gear 7 sleeved on the other end of the first transmission shaft 2 to rotate. The rotation of the second gear 7 drives the first gear 6 fixedly sleeved on the outer periphery of the needle 5 to rotate, driving the needle 5 to rotate, thereby completing the internal transmission of the dental mobile phone, and completing the operation through the rotating needle 5.

[0057] Due to the special design of the first gear 6 and the second gear 7 in this embodiment, the second gear 7 will not generate axial thrust on the first gear 6 when rotating, that is, the axial thrust generated on the first gear 6 is completely eliminated, thereby greatly reducing the friction between the bearings and further increasing the service life of the bearing 12.

[0058] Example 2

[0059] Figures 13 to 19 A dental handpiece speed increasing bending machine according to another embodiment of the present invention is schematically shown.

[0060] like Figures 13 to 19 As shown, the structure of the dental handpiece speed increasing bending machine of this embodiment is basically the same as that of the dental handpiece speed increasing bending machine in Example 1, and the difference is that:

[0061] The structures of the first gear 6 and the second gear 7 of this embodiment are different from those of Example 1, and the angle between the first gear 6 and the second gear 7 of this embodiment is 90°.

[0062] like Figures 16 to 19 As shown, the first gear 6 of this embodiment is a bevel gear and the number of teeth of the first gear 6 is 17. When the first gear 6 is a bevel gear, the force exerted by the second gear 7 on the first gear 6 is almost perpendicular to the outer wall of the first gear 6, so a small axial thrust is generated when it just contacts, but almost no axial thrust is generated during the rotation process, eliminating most of the axial force of the gear sleeved outside the needle 5.

[0063] One end of the second gear 7 is provided with an opening 71 that matches the first transmission shaft 2, and the other end is provided with a plurality of wedge-shaped teeth 72 distributed in a circumferential array, and the circumference of the outer wall of the wedge-shaped teeth 72 is the same as the diameter of the second gear 7. The wedge-shaped teeth 72 gradually become sharper from the root to the top. The number of wedge-shaped teeth 72 of the second gear 7 in this embodiment is 16. Therefore, when the second transmission member drives the second gear 7 to rotate, the top end of the wedge-shaped teeth 72 acts vertically on the tooth surface of the first gear 6. Since the first gear 6 is a bevel gear, most of the force of the wedge-shaped teeth 72 acting on the first gear 6 at the beginning is radial thrust, and only a small part is axial thrust. Therefore, this gear transmission structure can eliminate most of the axial thrust when in use, which is a significant improvement compared to the traditional axial thrust that exists throughout the entire process.

[0064] like Fig.18 and Fig.19 As shown, each wedge-shaped tooth 72 is formed by the three curved surfaces of the first curved surface 721, the second curved surface 722 and the third curved surface 723 and the bottom surface. The first curved surface 721, the second curved surface 722 and the third curved surface 723 are connected to each other. The first curved surface 721 is formed by the three segments of the first line a, the second line b and the third line c connected in sequence. The second curved surface 722 is formed by the three segments of the first line a, the fourth line d and the fifth line e connected in sequence. The third curved surface 723 is formed by the second line b and the fourth line d, and the third curved surface 723 is connected to the outer wall of the second gear 7 as a whole. The first curved surface 721 and the second curved surface 722 intersect at the first line a, and the first curved surface 721 and the second curved surface 722 are arranged symmetrically along the plane where the first line a is located. In this embodiment, the first line a, the second line b and the fourth line d are all arcs convex outward, and the third line c and the fifth line e are all straight lines.

[0065] Due to the special design of the first gear 6 and the second gear 7 in this embodiment, the axial thrust generated by the second gear 7 on the first gear 6 when rotating is mostly eliminated, thereby greatly reducing the friction between the bearing and the needle 5, thereby increasing the service life of the bearing 12.

[0066] The present invention partially or completely eliminates the axial force of the gear sleeved outside the needle 5 by changing the gear matching structure, greatly reduces the friction between the bearings, and increases the service life of the bearing 12; at the same time, it greatly reduces the generation of heat, thereby reducing the amount of cooling water used during the operation. With less water consumption, the operating surface can be seen clearly, indirectly providing the doctor with a highly clear operating space.

[0067] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the creative concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A dental handpiece speed increasing contra-angle machine, comprising a handpiece (1), a first transmission shaft (2) and a second transmission shaft (3), wherein one end of the first transmission shaft (2) is connected to the handpiece (1), and the other end is in driving connection with the second transmission shaft (3), and the first transmission shaft (2) and the second transmission shaft (3) have an angle, characterized in that: A needle (5) is installed in the machine head (1), and a bearing (12) and a first gear (6) are sleeved on the outer periphery of the needle (5); a second gear (7) is provided at one end of the first transmission shaft (2) connected to the machine head (1); the second gear (7) is meshed with the first gear (6); an angle is formed between the first gear (6) and the second gear (7); the angle between the straight line where the radial direction of the first gear (6) lies and the straight line where the radial direction of the second gear (7) lies is 120°; and the second gear (7) can at least eliminate part of the axial thrust generated on the first gear (6); The first gear (6) is a spur gear; One end of the second gear (7) is provided with an opening (71) that matches the first transmission shaft (2), and the other end is provided with a plurality of wedge-shaped teeth (72) distributed in a circumferential array and diverging outwards, wherein the wedge-shaped teeth (72) gradually become sharper from the root to the top; The wedge-shaped tooth (72) is formed by enclosing three curved surfaces, namely, a first curved surface (721), a second curved surface (722) and a third curved surface (723); the first curved surface (721), the second curved surface (722) and the third curved surface (723) are connected to each other; the first curved surface (721) is formed by enclosing three segments of lines, namely, a first line (a), a second line (b) and a third line (c); the second curved surface (722) is formed by enclosing three segments of lines, namely, a first line (a), a fourth line (d) and a fifth line (e); the first curved surface (721) and the second curved surface (722) intersect at the first line (a); the first curved surface (721) and the second curved surface (722) are symmetrically arranged along the plane where the first line (a) is located; the first line (a), the second line (b), the third line (c), the fourth line (d) and the fifth line (e) are all arcs convex outwards; When the first gear (6) is meshed with the second gear (7), the hypotenuse of the cross section of the wedge-shaped tooth (72) at the top of the second gear (7) is parallel to the horizontal line in the radial direction of the first gear (6), and the shape of the wedge-shaped tooth (72) can ensure that only radial force is generated when it contacts the first gear (6) during rotation.

2. The dental handpiece speed increasing bending machine according to claim 1, characterized in that: The invention also comprises a transition shaft (4), one end of which is transmission-connected to the first transmission shaft (2), and the other end of which is transmission-connected to the second transmission shaft (3); a third gear (21) is provided at the end of the first transmission shaft (2), and a fourth gear (31) is provided at the second transmission shaft (3); a fifth gear (41) and a sixth gear (42) are provided at both ends of the transition shaft (4), respectively; the third gear (21) is meshed with the fifth gear (41), and the fourth gear (31) is meshed with the sixth gear (42).

3. The dental handpiece speed increasing bending machine according to claim 2, characterized in that: The third gear (21) and the fifth gear (41) are both bevel gears, the fourth gear (31) is an internal gear, and the sixth gear (42) is a spur gear.

4. The dental handpiece speed increasing bending machine according to claim 2, characterized in that: It also includes a first shell (8), an elbow (9) and a second shell (10) which are connected in sequence, wherein the first shell (8) is connected to the machine head (1), and the first transmission shaft (2), the second transmission shaft (3) and the transition shaft (4) are all located in a space formed by the first shell (8), the elbow (9) and the second shell (10).

5. The dental handpiece speed increasing bending machine according to claim 4, characterized in that: A support block (91) is provided in the elbow (9), and the transition shaft (4) is supported by the support block (91).

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