Dental handpiece

Abstract

The present invention provides a dental handpiece that can suppress manufacturing costs, efficiently use supplied air energy, and be miniaturized. The present invention includes a head (13) that includes a rotation mechanism (31) having a collet (35) that holds a dental treatment tool (15) so as to be detachable and rotates the collet (35) by supplied compressed air, and a cylindrical grip portion (11) that has the head (13) at a tip end, has an air supply tube (17) that supplies compressed air to the rotation mechanism (31), and has a pressure regulating portion (50) that regulates the pressure of the compressed air, the pressure regulating portion (50) having a tube body (51) through which the compressed air passes, a hole portion (67) that penetrates a tube wall in the tube body (51), a ball (53) that is housed in the hole portion (67) and plugs the hole portion (67), and a ring-shaped elastic member (55) that is fitted to the tube body (51) and elastically presses the ball (53) from an outer peripheral side of the tube body (51).

Description

TECHNICAL FIELD

[0001] The present application relates to a dental handpiece. BACKGROUND

[0002] Patent Documents 1 and 2 disclose that, in a dental handpiece provided with a rotary mechanism such as an air turbine, pneumatic motor, etc. that is rotationally driven by compressed air, in order to suppress breakage of a dental treatment tool caused by high rotation speed of the rotary mechanism, generation of wear due to depletion of lubricating oil, a pressure regulating mechanism that regulates the pressure of the compressed air to an appropriate range is provided.

[0003] As shown in Figure 11 , the pressure regulating mechanism is provided with a cylindrical piston 1, a gas supply pipe 3 is arranged on the inner side of the piston 1, and a housing 5 is arranged on the outer side of the piston 1. The piston 1 is configured to slide in the axial direction between the gas supply pipe 3 and the housing 5, and a coil spring 7 housed in the housing 5 exerts a force to one side in the axial direction. In this pressure regulating mechanism, the pressure of the compressed air is applied to the end surface of the piston 1 on the opposite side to the coil spring 7, and when this pressure is greater than the exerted force of the coil spring 7, the piston 1 slides to the other side in the axial direction against the exerted force of the coil spring 7. As a result, the hole portion 5a formed in the housing 5, which is normally blocked by the piston 1, communicates with the hole portion 3a formed in the gas supply pipe 3, and the compressed air sent into the gas supply pipe 3 is discharged to the outside of the housing 5 through the hole portion 3a and the hole portion 5a, whereby the pressure is regulated.

[0004] Further, the parts such as the piston 1, the gas supply pipe 3, and the housing 5 that constitute the above-described pressure regulating mechanism are required to be machined with high precision, for example, to make the clearance of each part 10 μm or less, in order to suppress leakage of air. Therefore, the manufacturing cost increases.

[0005] Furthermore, even if the parts are machined with high precision, it is difficult to completely eliminate leakage of air from the clearance between the parts, and energy loss of the compressed air occurs, leading to a decrease in torque and rotation speed in the rotary mechanism.

[0006] Moreover, since the configuration is such that the cylindrical piston 1 slides in the axial direction, the entire length becomes long. Therefore, a large accommodation space is required, and this leads to an increase in the size of the entire handpiece.

[0007] PRIOR ART DOCUMENTS

[0008] PATENT DOCUMENTS

[0009] Patent Document 1: Japanese Patent No. 4147231

[0010] Patent Document 2: Chinese Patent Application Publication No. 106491217 SUMMARY

[0011] PROBLEMS TO BE SOLVED BY THE INVENTION

[0012] Therefore, an object of the present application is to provide a dental handpiece which can suppress manufacturing costs and efficiently use air supply energy, and which can be downsized.

[0013] Solution to Problem

[0014] The present application is configured by the following structure.

[0015] A dental handpiece comprising:

[0016] a head portion including a rotation mechanism having a collet that holds a dental treatment tool in a detachable manner and rotates the collet by compressed air supplied thereto; and

[0017] a cylindrical grip portion having the head portion provided at a tip end thereof and having an air supply tube that supplies the compressed air to the rotation mechanism,

[0018] the air supply tube having a pressure regulating portion that regulates the pressure of the compressed air,

[0019] the pressure regulating portion having:

[0020] a tube body through which the compressed air passes;

[0021] a hole portion that penetrates a wall of the tube body;

[0022] a ball that is housed in the hole portion and plugs the hole portion; and

[0023] a ring-shaped elastic member that is fitted to the tube body and elastically presses the ball from an outer peripheral side of the tube body.

[0024] Effects of the Invention

[0025] According to the present application, manufacturing costs can be suppressed and air supply energy can be efficiently used, and downsizing can be achieved. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a side view of the grip portion of the dental handpiece of the present application, taken along an axial direction.

[0027] Figure 2 is a cross-sectional view of the head portion of the dental handpiece.

[0028] Figure 3 is a cross-sectional view of the grip portion of the dental handpiece, taken along an axial direction, near a rear end thereof.

[0029] Figure 4 is a perspective view of the pressure regulating mechanism.

[0030] Figure 5 is a cross-sectional view of the pressure regulating mechanism, taken along an axial direction.

[0031] Figure 6 It is along Figure 5 A sectional view along line VI-VI.

[0032] Figure 7 This is a three-dimensional view of the pressure regulating mechanism of Modified Example 1.

[0033] Figure 8 This is a cross-sectional view along the axial direction of the pressure regulating mechanism of Modified Example 1.

[0034] Figure 9 It is along Figure 8 A cross-sectional view of the IX-IX line.

[0035] Figure 10 This is a cross-sectional view along the axial direction of the pressure regulating mechanism of Modified Example 2.

[0036] Figure 11 This is a cross-sectional view along the axial direction near the rear end of the gripper of a dental handpiece in a conventional pressure regulating mechanism.

[0037] Explanation of reference numerals in the attached figures

[0038] 11: Gripper; 13: Head; 15: Dental processing tool; 17: Air supply tube; 21, 21A, 21B: Pressure regulating mechanism; 31: Rotating mechanism; 35: Hoop; 50, 50A: Pressure regulating part; 51, 71, 91: Tube body; 53: Ball bearing; 55: Annular elastic member; 67: Hole; 67a: Small diameter hole; 69: Groove; 81: Branch tube; 100: Dental handpiece. Detailed Implementation

[0039] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0040] Figure 1 This is a side view obtained by cutting open the gripping portion 11 of the dental handpiece 100 of the present invention along the axial direction.

[0041] like Figure 1 As shown, the dental handpiece 100 of this embodiment has a gripping portion 11 and a head 13. The head 13 is located at the top of the gripping portion 11, and a dental processing tool 15 is attached to the head 13. The dental handpiece 100 of this embodiment is an air turbine handpiece that rotates the dental processing tool 15 by means of compressed air.

[0042] The gripping part 11 has a cylindrical housing 12, inside which an air supply pipe 17 and a water supply pipe 19 are provided. The air supply pipe 17 has a pressure regulating mechanism 21 at its rear end. The water supply pipe 19 has a check valve 23 at its rear end. Furthermore, in the gripping part 11, the internal space of the housing 12 is configured as an exhaust flow path 25.

[0043] The rear end of the grip portion 11 is provided as a connection portion 27 to which a coupling (not shown) is connected. The coupling is connected to a flexible tube (not shown) that extends from a dental unit (not shown) that supplies compressed air and water. The compressed air supplied from the dental unit is supplied to the air supply tube 17 of the grip portion 11. The compressed air supplied to the air supply tube 17 passes through the pressure regulating mechanism 21 and is supplied toward the head portion 13. In addition, the water supplied from the dental unit is supplied to the water supply tube 19 of the grip portion 11. The water supplied to the water supply tube 19 passes through the check valve 23 and is supplied toward the head portion 13. In the water supply tube 19, the backflow of the water is inhibited by the check valve 23.

[0044] Figure 2 is a cross-sectional view of the head portion 13 of the dental handpiece 100.

[0045] As shown in Figure 2 , the head portion 13 has a head case 33 that houses a rotation mechanism 31 inside. The rotation mechanism 31 has a bar sleeve 35, a rotor 37, a pair of ball bearings 39, and a cartridge case 41.

[0046] The bar sleeve 35 holds the rod-shaped dental treatment tool 15 so as to be detachable, and the rotor 37 is provided on the outer periphery of the bar sleeve 35. The pair of ball bearings 39 is provided to the cartridge case 41. The bar sleeve 35 is supported by the ball bearings 39 so as to be rotatable at both end portions.

[0047] In the head portion 13, the compressed air supplied from the air supply tube 17 is blown toward the rotor 37. Thereby, the bar sleeve 35 that holds the dental treatment tool 15 is rotated. The compressed air blown to the rotor 37 is discharged from the head portion 13 to an exhaust flow path 25 constituted by the internal space of the case 12 of the grip portion 11.

[0048] In addition, a discharge port 43 that communicates with the water supply tube 19 is provided in the vicinity of the head portion 13 in the grip portion 11, and the water supplied from the water supply tube 19 is discharged from the discharge port 43. In addition, a blowout port 47 that communicates with a branch path 45 branched from the air supply tube 17 is provided at a position adjacent to the discharge port 43, and the compressed air supplied from the branch path 45 is blown out from the blowout port 47. Thereby, in the dental handpiece 100, by blowing out the compressed air from the blowout port 47 at the same time as the water discharged from the discharge port 43 in the vicinity of the tip end of the head portion 13, the water can be sprayed in a mist state.

[0049] Figure 3 is a cross-sectional view along the axial direction of the vicinity of the rear end of the grip portion 11 of the dental handpiece 100. Figure 4 is a perspective view of the pressure regulating mechanism 21. Figure 5 is a cross-sectional view along the axial direction of the pressure regulating mechanism 21.

[0050] As shown in Figures 3 to 5 the pressure adjusting mechanism 21 provided in the air supply tube 17 is provided with a tube body 51 having a pressure adjusting portion 50. The pressure adjusting portion 50 of the tube body 51 has a plurality of ball bearings 53 and a ring-shaped elastic member 55.

[0051] The tube body 51 is formed in a cylindrical shape having a flow path 57. The tube body 51 is connected to the air supply tube 17 at one end portion 51a and is connected to a connection portion (not shown) of an end portion of a flexible tube extending from a dental unit that discharges compressed air at the other end portion 51b. The other end portion 51b of the tube body 51 is held by an adaptor 28 of the connection portion 27 constituting the grip portion 11.

[0052] The tube body 51 has a fitting hole portion 59 having a larger inner diameter than that of the flow path 57 at the one end portion 51a side, and an end portion of the air supply tube 17 is fitted in the fitting hole portion 59. An O-ring 61 is provided in the fitting hole portion 59, and the fitting hole portion 59 is sealed from the air supply tube 17 by the O-ring 61.

[0053] In the tube body 51, the one end portion 51a side is provided as a large diameter portion 63, and the other end portion 51b side is provided as a small diameter portion 65 having a smaller diameter than that of the large diameter portion 63.

[0054] In the tube body 51, the pressure adjusting portion 50 is provided at a position near the small diameter portion 65 in the large diameter portion 63. The pressure adjusting portion 50 has a plurality of hole portions 67 that pass through the inside and outside of the tube wall of the tube body 51. In this example, the tube body 51 has three hole portions 67 formed at equiangular intervals in the circumferential direction. The ball bearings 53 are respectively accommodated in the hole portions 67.

[0055] Further, in the pressure adjusting portion 50 of the tube body 51, a groove portion 69 is formed in the outer periphery of the large diameter portion 63. The groove portion 69 is formed at a position passing through the formation position of the hole portion 67 in the circumferential direction. The groove portion 69 has a width narrower than the diameter of the ball bearings 53 accommodated in the hole portions 67.

[0056] The ring-shaped elastic member 55 is formed in a ring shape, for example, by an elastic material such as rubber. The ring-shaped elastic member 55 is formed in a circular shape in cross section. As the ring-shaped elastic member 55, for example, an O-ring can be used. The ring-shaped elastic member 55 is fitted to the outer periphery of the tube body 51 and is accommodated in the groove portion 69 formed in the large diameter portion 63. The ring-shaped elastic member 55 fitted to the outer periphery of the tube body 51 and accommodated in the groove portion 69 is accommodated in the groove portion 69 in such a manner as not to protrude from the outer peripheral surface of the tube body 51, and displacement of the ring-shaped elastic member 55 to a position in the axial direction of the tube body 51 is suppressed.

[0057] Further, in a state where the annular elastic member 55 is housed in the groove portion 69, a gap C is formed between the annular elastic member 55 housed in the groove portion 69 and the inner peripheral surface of the hole portion 67 in the portion where the hole portion 67 is formed in the outer periphery of the pipe body 51.

[0058] Figure 6 is a cross-sectional view along the VI-VI line of Figure 5

[0059] As shown in Figure 6 , the hole portion 67 formed in the pressure regulating portion 50 of the pipe body 51 has a small-diameter hole portion 67a with an inner diameter smaller than the diameter of the ball 53 on the inner peripheral side of the pipe body 51. The ball 53 is housed in the hole portion 67 from the outer peripheral side of the pipe body 51. The ball 53 housed in the hole portion 67 is caught in the small-diameter hole portion 67a on the inner peripheral side of the pipe body 51 in the hole portion 67, and movement of the ball 53 toward the inner peripheral side of the pipe body 51 is restricted.

[0060] The balls 53 housed in the respective hole portions 67 are pressed toward the inner peripheral side of the pipe body 51 by the elastic force of the annular elastic member 55 fitted to the outer periphery of the pipe body 51 and housed in the groove portion 69. Thus, the balls 53 housed in the respective hole portions 67 are in a state of touching the edge portion of the small-diameter hole portion 67a of the hole portion 67, and the respective hole portions 67 are maintained in a state of being plugged by the balls 53.

[0061] In the dental handpiece 100 provided with the pressure regulating mechanism 21 having the above-described configuration, compressed air is supplied from the dental unit through the flexible tube connected by the coupling member. This supplied compressed air passes through the pipe body 51 constituting the pressure regulating mechanism 21 and is fed to the air supply tube 17. Also, in the head portion 13, the compressed air is blown from the air supply tube 17 toward the rotor 37, and the collet 35 holding the dental treatment tool 15 is rotated. The compressed air blown to the rotor 37 is discharged from the head portion 13 to the exhaust flow path 25 constituted by the internal space of the housing 12 of the grip portion 11, and is discharged to the dental unit side through the exhaust path of the flexible tube.

[0062] At this time, the compressed air is sometimes supplied from the dental unit at a pressure exceeding the appropriate range. In this case, in the pressure regulating mechanism 21, as the internal pressure of the air supply tube 17 rises, the balls 53 housed in the respective hole portions 67 of the pressure regulating portion 50 of the pipe body 51 displace to the outside in the radial direction of the pipe body 51 against the applied force generated by the annular elastic member 55. Then, these balls 53 depart from the edge portion of the small-diameter hole portion 67a of the hole portion 67, and the compressed air in the pipe body 51 flows out to the exhaust flow path 25 on the outer peripheral side of the pipe body 51 from the gap between the hole portion 67 and the balls 53, and the internal pressure of the air supply tube 17 is maintained in the appropriate range.

[0063] ​As described above, according to the dental handpiece 100 of the present embodiment, the pressure of the supplied compressed air is maintained in an appropriate range by the pressure regulating portion 50 of the pressure regulating mechanism 21 provided to the air supply tube 17, and thus in the rotation mechanism 31, the breakage of the dental treatment tool 15 due to a high rotation speed of the sleeve 35 and the generation of wear due to the exhaustion of the lubricating oil can be suppressed.

[0064] Further, the pressure regulating portion 50 of the pressure regulating mechanism 21 is configured such that the ball 53 is housed in the hole portion 67 formed in the tube body 51, and the ball 53 is forced from the outer peripheral side by the annular elastic member 55 embedded in the tube body 51. Thus, compared to the pressure regulating mechanism of the existing configuration in which the compressed air is regulated by a piston that can slide in the axial direction, the number of parts can be reduced, and further, the cost of the parts themselves can be suppressed.

[0065] Further, since there are no parts that slide in the axial direction, the length in the axial direction can be shortened to seek miniaturization, and the narrow space in the grip portion 11 can be easily accommodated.

[0066] Further, the loss of the air supply energy due to the leakage of the compressed air from the gap between the parts can also be suppressed.

[0067] Note that in the above embodiment, the pressure regulating portion 50 is provided to the tube body 51 different from the air supply tube 17, but the pressure regulating portion 50 can be provided to the tube body constituted by the air supply tube 17 to constitute the pressure regulating mechanism 21. According to this configuration, further reduction in the number of parts can be sought.

[0068] Next, a modification of the pressure regulating mechanism provided to the dental handpiece 100 will be described. Note that regarding the same constituent parts as the pressure regulating mechanism 21 of the above embodiment, the same symbols are marked and the description will be omitted.

[0069] (Modified Example 1)

[0070] Figure 7 is a perspective view of the pressure regulating mechanism 21A of the modified example 1. Figure 8 is a cross-sectional view of the pressure regulating mechanism 21A of the modified example 1 along the axial direction. Figure 9 is a cross-sectional view along the IX-IX line of Figure 8 .

[0071] As shown in Figure 7 and Figure 8 , the pressure regulating mechanism 21A of the modified example 1 is provided with a tube body 71 having two pressure regulating portions 50A.

[0072] The tube body 71 is formed in a cylindrical shape having a flow path 77. The tube body 71 is connected to the air supply tube 17 at one end portion 71a and is connected to a connection portion of a flexible tube at the other end portion 71b, wherein the flexible tube extends from a dental unit that discharges compressed air.

[0073] The tube body 71 has a fitting hole 79 with an O-ring 61 on one end 71a side, into which the end of the air supply pipe 17 is inserted. Furthermore, in the flow path 77 of the tube body 71, the fitting hole 79 side is provided as a small-diameter flow path 77a.

[0074] In the pipe body 71, one end 71a is designated as an intermediate diameter portion 73, and the other end 71b is designated as a small diameter portion 75, the small diameter portion 75 being smaller in diameter than the intermediate diameter portion 73. Furthermore, in the pipe body 71, the axially intermediate portion of the intermediate diameter portion 73 is designated as a large diameter portion 74, the large diameter portion 74 being larger in diameter. Two pressure regulating portions 50A are provided in the large diameter portion 74 of the pipe body 71, spaced apart axially. It should be noted that in the large diameter portion 74 of the pipe body 71, a recessed portion 74a is formed on the side that becomes the water supply pipe 19 to avoid interference with the water pipe 19.

[0075] The pressure regulating part 50A has a hole 67 for receiving a ball 53, and a groove 69 with a width narrower than the diameter of the ball 53 is formed at the location where the hole 67 is formed. Furthermore, an annular elastic member 55 is received in the groove 69.

[0076] like Figure 9 As shown, the hole 67 formed in the tube body 71 has a small-diameter hole 67a on the inner circumferential side of the tube body 71 and a large-diameter hole 67b on the outer circumferential side of the tube body 71. A ball 53, received in the hole 67 from the outer circumferential side of the tube body 71, is engaged with the small-diameter hole 67a on the inner circumferential side of the tube body 71 within the hole 67, thus restricting the movement of the ball 53 towards the inner circumferential side of the tube body 71. In the pressure regulating section 50A, the ball 53 is pressed by the elastic force of the annular elastic member 55 and contacts the edge of the small-diameter hole 67a of the hole 67, thereby maintaining the hole 67 in a blocked state by the ball 53.

[0077] In the pressure regulating mechanism 21A of this modified example 1, when compressed air is supplied from the dental unit at a pressure exceeding an appropriate range, the balls 53 housed in the orifices 67 of each pressure regulating section 50A of the pressure regulating mechanism 21A overcome the applied force generated by the annular elastic member 55 and are displaced toward the outer periphery of the tube body 71. As a result, the balls 53 move away from the edge of the small-diameter orifice 67a of the orifice 67, and the compressed air inside the tube body 71 flows out through the gap between the orifice 67 and the balls 53 toward the exhaust passage 25 on the outer periphery of the tube body 71.

[0078] Note that each pressure regulating portion 50A regulates pressure in one hole portion 67 in which the ball 53 is housed. Therefore, a large-diameter hole portion 67b is formed on the outer peripheral side of the pipe body 71 in the hole portion 67, and air is easily discharged at the time of pressure regulation. Further, the material of the annular elastic member 55 can be selected to adjust the elastic force, and thus air is easily discharged at the time of pressure regulation.

[0079] Thus, in the case of the pressure regulating mechanism 21A of the modified example 1 as well, when the compressed air exceeds the appropriate range, the compressed air is discharged from each pressure regulating portion 50A provided in the pipe body 71, and thus the internal pressure of the air supply pipe 17 is maintained in the appropriate range. Thus, in the rotation mechanism 31, the breakage of the dental treatment tool 15 due to the high rotation speed of the sleeve 35 and the generation of wear due to the exhaustion of the lubricating oil can be suppressed.

[0080] Further, in each pressure regulating portion 50A, the pressure regulating mechanism 21A of the modified example 1 houses the ball 53 to which the annular elastic member 55 applies a force in one hole portion 67, and thus the configuration can be simplified.

[0081] Furthermore, the plurality of pressure regulating portions 50A are provided at intervals in the axial direction of the pipe body 71, and thus the pressure regulating function can have redundancy, and the safety can be improved.

[0082] (Modified Example 2)

[0083] Figure 10 is a cross-sectional view of the pressure regulating mechanism 21B of the modified example 2 along the axial direction.

[0084] As shown in Figure 10 , the pressure regulating mechanism 21B of the modified example 2 is attached to a branch pipe 81 provided in the air supply pipe 17. In the branch pipe 81, one end is connected to the air supply pipe 17, and the middle portion is bent and extends along the air supply pipe 17. Furthermore, the pressure regulating mechanism 21B is connected to the other end of the branch pipe 81.

[0085] The pressure regulating mechanism 21B has a pipe body 91 in which a pressure regulating portion 50 is provided. The pipe body 91 is formed in a bottomed cylindrical shape. The pipe body 91 has a fitting hole portion 93 in which an O-ring 61 is provided, and the end portion of the branch pipe 81 branched from the air supply pipe 17 is fitted. The pipe body 91 has a large-diameter portion 95 on the side of the end portion opposite to the side connected to the branch pipe 81, and the pressure regulating portion 50 is provided in the large-diameter portion 95, the pressure regulating portion 50 houses balls 53 in three hole portions 67, and each ball 53 is applied with a force by an annular elastic member 55.

[0086] In the pressure regulating mechanism 21B of this modification example 2, when compressed air is supplied from the dental unit at a pressure exceeding the appropriate range, the internal pressure of the pipe body 91 of the pressure regulating mechanism 21B connected to the branch pipe 81 rises, and the balls 53 housed in each hole portion 67 of the pressure regulating portion 50 are displaced in the outer peripheral direction of the pipe body 91 against the applied force generated by the annular elastic member 55, respectively. Thereby, each ball 53 departs from the edge portion of the small-diameter hole portion 67a of the hole portion 67, and the compressed air in the pipe body 91 flows out from the gap between the hole portion 67 and the ball 53 to the exhaust flow path 25 on the outer peripheral side of the pipe body 91, and the internal pressure of the supply air pipe 17 is maintained in the appropriate range.

[0087] Thus, in the case of the pressure regulating mechanism 21B of the modification example 2 as well, when the compressed air exceeds the appropriate range, the compressed air is discharged from the pressure regulating portion 50 provided to the pipe body 91, whereby the internal pressure of the supply air pipe 17 is maintained in the appropriate range. Thereby, in the rotation mechanism 31, it is possible to suppress breakage of the dental treatment tool 15 due to a high rotation speed of the cuff 35, and generation of wear due to exhaustion of the lubricating oil.

[0088] Further, the pressure regulating mechanism 21B of the modification example 2 is provided to the branch pipe 81 branched from the supply air pipe 17, and thus it is possible to shorten the supply path of the compressed air, and it is possible to further shorten the entire length of the dental handpiece 100.

[0089] Note that, in the modification example 2, the pressure regulating portion 50 can also be provided to a branch pipe branched from the supply air pipe 17 and further merged with the supply air pipe 17. In this case, the compressed air branched from the supply air pipe 17 to the branch pipe is merged with the supply air pipe 17 after passing through the pressure regulating portion 50 of the branch pipe.

[0090] Thus, the present application is not limited to the above-described embodiments, and the case where the respective configurations of the embodiments are combined with each other, the case where the present application is modified and applied based on the description and publicly known technologies of the present application by those skilled in the art are also intended by the present application, and are included in the scope of the present application.

[0091] As described above, the following is disclosed in the present specification.(1) A dental handpiece including:

[0092] a head portion including a rotation mechanism having a cuff that holds a dental treatment tool in a detachable manner and rotates the cuff by supplied compressed air; and

[0093] a tubular grip portion having the head portion provided at a top end and having a supply air pipe that supplies compressed air to the rotation mechanism,

[0094] the supply air pipe having a pressure regulating portion that regulates the pressure of the compressed air,

[0095] the pressure regulating portion having:

[0096] a pipe body through which the compressed air passes;

[0097] a hole portion that penetrates a pipe wall in the pipe body;

[0098] a ball that is housed in the hole portion and plugs the hole portion; and

[0099] a ring-shaped elastic member that is fitted to the pipe body and elastically presses the ball from an outer peripheral side of the pipe body.

[0100] According to the dental handpiece, in the pressure regulating portion provided in the air supply pipe, when the pressure of the supplied compressed air exceeds an appropriate range, the ball housed in the hole portion is displaced in the outer peripheral direction of the pipe body by the pressure against the applied force by the ring-shaped elastic member. Thus, the compressed air in the pipe body flows out from the gap between the hole portion and the ball to the outer peripheral side of the pipe body, and the pressure of the compressed air is maintained in the appropriate range. Thus, in the rotation mechanism, the breakage of the dental treatment tool due to the high rotation speed of the cuff, and the generation of wear due to the exhaustion of the lubricating oil can be suppressed.

[0101] Further, the pressure regulating portion is configured such that the ball housed in the hole portion formed in the pipe body is applied with force from the outer peripheral side by the ring-shaped elastic member fitted to the pipe body. Thus, compared with the pressure regulating mechanism of the existing configuration in which the compressed air is pressure regulated by a piston that can slide in the axial direction, the number of parts can be reduced, and further, the cost of the parts themselves can be suppressed.

[0102] Further, since there is no part that slides in the axial direction, the length in the axial direction can be shortened to seek miniaturization, and the part can be easily housed in the narrow space in the grip portion.

[0103] Further, the loss of the air supply energy due to the leakage of the compressed air from the gap between the parts can also be suppressed.

[0104] Thus, according to the dental handpiece of the present application, the manufacturing cost can be suppressed and the air supply energy can be efficiently utilized, and further, miniaturization can be achieved.

[0105] (2) The dental handpiece according to (1), wherein

[0106] a pressure regulating mechanism having the pressure regulating portion is connected to the air supply pipe.

[0107] According to the dental handpiece, the air supply pipe can easily have the pressure regulating function by the pressure regulating portion of the pressure regulating mechanism connected to the air supply pipe.

[0108] (3) The dental handpiece according to (1) or (2), wherein

[0109] the pipe body is formed with a plurality of the hole portions at intervals in the circumferential direction,

[0110] The holes respectively contain the balls,

[0111] The balls are elastically pressed from the outer peripheral side of the tube body by the ring-shaped elastic member.

[0112] According to the dental handpiece, the holes formed at intervals in the circumferential direction contain the balls, and the balls are pressed from the outer peripheral side of the tube body by the ring-shaped elastic member. Therefore, when the pressure of the compressed air exceeds an appropriate range, the balls of the holes are displaced, and the pressure of the compressed air can be quickly suppressed.

[0113] (4) The dental handpiece according to any one of (1) to (3), wherein

[0114] The hole has a small-diameter hole portion having a smaller diameter than the diameter of the ball on the inner peripheral side of the tube body,

[0115] The ball is contained in the hole from the outer peripheral side of the tube body and is engaged in the small-diameter hole portion.

[0116] According to the dental handpiece, the ball contained in the hole is engaged by the small-diameter hole portion, and thus the ball can be arranged at an appropriate position in the hole.

[0117] (5) The dental handpiece according to any one of (1) to (4), wherein

[0118] A groove portion having a width narrower than the diameter of the ball is formed in the outer periphery of the tube body at a position passing through the formation site of the hole in the circumferential direction,

[0119] The ring-shaped elastic member is contained in the groove portion.

[0120] According to the dental handpiece, a gap is formed between the ring-shaped elastic member contained in the groove portion and the inner peripheral surface of the hole in the formation site of the hole in the outer periphery of the tube body. Thus, the compressed gas can be smoothly discharged from the gap.

[0121] (6) The dental handpiece according to any one of (1) to (5), wherein

[0122] A plurality of the pressure regulating portions are provided at intervals in the axial direction of the tube body.

[0123] According to the dental handpiece, the plurality of pressure regulating portions are provided at intervals in the axial direction of the tube body, and thus the pressure regulating function can have redundancy, and safety can be improved.

[0124] (7) The dental handpiece according to any one of (1) to (6), wherein

[0125] The pressure regulating portion is provided in a branch tube branched from the gas supply tube.

[0126] According to the dental handpiece, the pressure regulating portion is provided in the branch pipe branched from the air supply pipe, so that the supply path of the compressed air can be shortened, and the entire length of the dental handpiece can be shortened.

Claims

1. A dental handpiece comprising: a head portion including a rotation mechanism having a collet that holds a dental treatment tool in a detachable manner and rotates the collet by compressed air supplied thereto; and a cylindrical grip portion having a supply tube that supplies the compressed air to the rotation mechanism, the head portion being provided at a tip end of the grip portion, the supply tube having a pressure regulating portion that regulates the pressure of the compressed air in the supply tube, the pressure regulating portion including: a tube body through which the compressed air passes; a hole portion that penetrates a wall of the tube body; a ball that is accommodated in the hole portion and plugs the hole portion; and a ring-shaped elastic member that is fitted to the tube body and exerts a force on the ball from an outer peripheral side of the tube body.

2. The dental handpiece according to claim 1, wherein a pressure regulating mechanism having the pressure regulating portion is connected to the supply tube.

3. The dental handpiece according to claim 1, wherein a plurality of the hole portions are formed in the tube body at intervals in a circumferential direction, the balls are respectively accommodated in the hole portions, and the balls are urged by the ring-shaped elastic member from the outer peripheral side of the tube body.

4. The dental handpiece according to any one of claims 1 to 3, wherein the hole portion has a small-diameter hole portion having a smaller diameter than a diameter of the ball on an inner peripheral side of the tube body, and the ball is accommodated in the hole portion from the outer peripheral side of the tube body and is engaged in the small-diameter hole portion.

5. The dental handpiece according to any one of claims 1 to 3, wherein a groove portion having a width narrower than the diameter of the ball is formed in the outer periphery of the tube body in correspondence with the hole portion in the circumferential direction, and the ring-shaped elastic member is accommodated in the groove portion.

6. The dental handpiece according to any one of claims 1 to 3, wherein a plurality of the pressure regulating portions are provided at intervals in an axial direction of the tube body.

7. The dental handpiece according to any one of claims 1 to 3, wherein the pressure regulating portion is provided in a branch tube that branches from the supply tube. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Images