JPH04141161A - Dental handpiece - Google Patents

Abstract

PURPOSE:To keep a cooling water from leaking within a hand-piece by including a flow control valve which adjusts a valve opening according to a size of a pressure of the cooling water on the secondary side as provided in the course of a path of the cooling water to vary a supply of the cooling water to a cooling water jetting part according to a jetting value of the cooling water from a dental bar. CONSTITUTION:A flow control valve 40 has a valve chamber 41 and a balancing chamber 42 within a core 31. The balancing chamber 42 is arranged on the side closer to a head part 3 than the valve chamber 41 and the balancing chamber 42 is connected to the valve chamber 41 through a communicating hole 43. The valve chamber 41 is linked to a cooling water supply pipe 38 through a communicating hole 44 and a part linked to the communicating hole 43 in the valve chamber 41 forms a valve seat 45 comprising a tapered surface. When a pressure of air is large, a valve opening increases and a larger amount of a cooling water is supplied to a cooling water supply pipe 39 with an increase in the pressure of the cooling water flowing into a chamber 51 of the balancing chamber 42. By the contrary, the valve opening decreases with a smaller pressure of the air and the pressure of the cooling water flowing into the chamber 51 reduces. Thus, only a small amount of the cooling water is supplied to the cooling water supply pipe 39.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a dental handpiece that supports and rotates a dental bur for cutting teeth, crowns, etc.

[Prior Art] The present applicant has proposed a dental bur having a cooling water flow hole (Japanese Patent Application Laid-Open No. 63-318937), and a dental handpiece (Japanese Patent Application Laid-Open No. 1-995) that supports and rotates this dental bur.
No. 50, Japanese Unexamined Patent Publication No. 1-110358, etc.).

The above-mentioned dental bur has a cutting part at the tip and a cooling water circulation hole inside, so that cooling water can be sprayed from the injection hole at the tip while cutting teeth. .

On the other hand, the dental handpiece includes a holder that supports the dental bur, a drive device that rotates the holder together with the dental bur, and a cooling water passage whose one end is connected to a cooling water supply source. A cooling water injection part that is provided at the tip of this cooling water passage and sends cooling water to the cooling water distribution hole of the dental bur;
The main components are: Incidentally, the standard drive device uses a fluid such as water or air as a drive source, and the holding body is provided with blades, and the blades are rotated by spraying fluid onto the blades. However, it is also possible to use a motor drive as this drive device.

By the way, in order to cut teeth etc., it is necessary to rotate the dental bur at a high speed of about 3Q million revolutions per minute. The seal uses a non-contact sealing mechanism. This sealing mechanism includes, for example, Japanese Unexamined Patent Publication No. 1-995
There are those that utilize a pump action as disclosed in Japanese Patent Application No. 50, and those that utilize an air seal as disclosed in Japanese Patent Application Laid-Open No. 110358/1989.

[Problems to be Solved by the Invention] In the conventional dental handpiece configured as described above, a substantially constant amount of cooling water is always supplied to the dental bur from the cooling water injection section.

However, the amount of cooling water jetted from the dental bur is not always constant. For example, when the injection hole of the dental bur is blocked by teeth or the injection hole is clogged with chips, the amount of cooling water jetted from the dental bur decreases.

When the amount of cooling water jetted from the dental bur decreases, the excess cooling water leaks from the non-contact seal, wets the bearing that supports the holder, rusts the bearing, and causes damage to the holder. It had the disadvantage of causing rotational problems.

This invention was made in view of the problems of the prior art described above, and its purpose is to control the amount of cooling water supplied to the cooling water injection section according to the amount of cooling water jetted from the dental bur. The present invention aims to provide a dental handpiece that prevents cooling water from leaking inside the handpiece.

[Means for solving the problem] This invention was made to achieve the above object,
A summary of this can be found in the two dental tools listed below.

(1) A dental handpiece in which a driving device driven by a fluid is built in, and the driving device rotates a dental bur having a cooling water flow hole, (a) a non-contact sealing mechanism is used to connect the dental (b) a cooling water passage connecting the cooling water injection part and a cooling water supply source; (c) a flow control valve provided in the middle of the cooling water passage, controlled by the fluid after driving the drive device, and adjusting the valve opening according to the magnitude of the pressure of the fluid; Dental handpiece.

(2) A dental nosepiece incorporating a drive device for rotating a dental bur having a cooling water flow hole, (a) connected to the dental bur via a non-contact sealing mechanism, a cooling water injection section that supplies cooling water to the cooling water distribution hole of the dental bur; (b) a cooling water passage that connects the cooling water injection section and the cooling water supply source; (c) the cooling water passage that connects the cooling water injection section and the cooling water supply source; A dental handpiece, comprising: a flow control valve that is provided in the middle and adjusts the valve opening according to the magnitude of the cooling water pressure on the secondary side.

If the drive device that rotates the dental bur is a device driven by fluid, when the tip of the cooling water flow hole is blocked by teeth and the amount of cooling water jetted is reduced, the amount of water ejected from the teeth will be reduced. It has been confirmed that the frictional resistance is large, which reduces the rotational speed of the dental bur. When the rotational speed of the dental bur is high, the pressure of the fluid after driving the driving device is also high, and when the rotational speed is low, the pressure is also low. In the first invention, a flow control valve whose opening degree is controlled by the pressure of the fluid is arranged in the middle of the cooling water passage of the dental nosepiece. This flow control valve has
When the pressure of the fluid mentioned above is high, the valve opening increases to increase the cooling water pressure on the secondary side, and when the pressure of the fluid mentioned above is low, the valve opening decreases and the cooling water pressure on the secondary side increases. Adopts a flow control valve that operates to lower the flow rate. Then, when the amount of cooling water jetted from the dental bur is large, the amount of cooling water supplied from the cooling water injection part to the dental bur increases, and conversely, the amount of cooling water jetted from the dental bur increases. When the amount of cooling water is small, the amount of cooling water supplied from the cooling water injection section to the dental bur decreases.

Further, in the second invention, a flow rate control valve is provided in the middle of the cooling water passage of the dental handpiece, and this flow rate control valve includes:
A flow control valve is used that operates to increase the valve opening when the cooling water pressure on the secondary side is low, and to decrease the valve opening when the secondary side cooling water pressure increases. If the amount of cooling water injected from the dental bur is small, the cooling water pressure on the secondary side of the flow control valve will increase, but in that case, the flow control valve will operate in the closing direction and the pressure on the secondary side will increase. This can lower the cooling water flow rate. In the case of the second invention, the driving device for rotating the dental bur is not limited to a type driven by fluid, but may be a type driven by a motor, for example.

[Example] Hereinafter, an example of the present invention will be described based on the drawings from FIG. 1 to FIG. 4.

FIG. 1 is an overall external perspective view of the dental handpiece.

The dental handpiece 1 includes a rod-shaped arm portion 2 and a shaft provided at the tip of the arm portion 2.

It has a door portion 3. The arm portion 2 is a portion to be grasped by the operator, and the arm portion 3 is a portion that rotatably supports the dental knife.

First, the head section 3 will be explained. The head section 3 has a head section main body 4 and a cap 5. As shown in FIG. 2, a storage hole 6 is formed in the head main body 4, penetrating from the lower surface 4a to the upper surface, and the cap 5 is screwed and fixed to the upper end of the storage hole 6.

Bearings 8 and 9 are fixed to the lower end of the storage hole 6 of the head main body 4 and the lower end of the cap 5, and a holder (drive device) 10 is rotatably supported by these bearings 8 and 9. has been done. The holding body 10 includes a cylindrical tube portion 11;
A large number of blades 1 provided on the outer peripheral surface of the intermediate portion of this cylindrical portion 11
2, and the holder 10 is driven to rotate by blowing high pressure air onto the blades 12. This high-pressure air is blown from a high-pressure air supply passage 13 provided inside the head main body 4, and the high-pressure air that is used for driving and performs the service is passed through an exhaust passage 13 formed inside the hennod main body 4. It is designed to be exhausted to the outside through.

A mounting hole 15 is formed in the center of the cylindrical portion 11 of the holder 10 and extends upward from the lower end surface. This mounting hole 15 has a large diameter hole 16 on the lower end side and a small diameter hole 17 on the upper end side.
It is composed of. A cylindrical gripping member 18 made of an elastic material is inserted and fixed into the large diameter hole 16 . and,
The shank portion B of the dental bur A is positioned by fitting into the small diameter hole portion 17, and the gripping member 18
It is designed to be held by fitting into the handle.

The dental bur A has a blade portion C made of an abrasive grain layer formed at its tip, and a cooling water flow hole penetrating from the base end surface to the distal end surface is formed inside the burr A. and,
As will be described later, cooling water is injected from the injection hole E at the tip of this cooling water circulation hole.

A tapered hole l9 is formed at the upper end of the cylindrical portion 11 and extends downward from the upper end surface and is connected to the small diameter hole 17. In addition, a substantially cylindrical cap 2 is provided at the upper end of the cylindrical portion 1.
0 is fixed. A portion defined by the inner wall of the cap 20 and the inner surface of the Taper hole 19 is a pump chamber 21.
It has become.

On the other hand, a nozzle portion (cooling water injection portion) 22 is provided protruding from the center of the ceiling portion of the cap 20 and extends in a direction approaching the holder 10 . The tip of the nozzle part 22 is connected to the cap 20.
The pump chamber 21 passes through a hole 23 formed in the center of the ceiling of the
A screw member 24 is inserted into the inside, and a screw member 24 is inserted outside.
is fixed. The outer peripheral surface of the nozzle part 22 and the hole 23
A slight gap is formed between the inner circumferential surface of the holder and the inner circumferential surface of the holder, so that the holder is maintained in a non-contact state. The screw member 24 serves as a pump to send out the cooling water swirling within the pump chamber 21 in the direction of the cooling water flow hole of the dental bur A, and by this pumping action, the hole 23 of the cap 20 is Even if there is a gap between the
The space between them is sealed.

In addition, a cooling water passage 25 is provided in the head main body 4 and the cap 20.
is formed, and this cooling water passage 25 is connected to the cap 2.
It passes through the nozzle portion 22 of No. 0 and further penetrates the screw member 24, with its tip facing the base end of the cooling water flow hole of the dental bur A.

In FIG. 2, reference numerals 26 and 27 indicate cooling water supply passages and compressed air supply passages that are used auxiliary.

Next, the arm portion of the dental handpiece 1 will be explained.

FIG. 3 shows the internal structure of the arm portion 2 in the first invention.

The arm portion 2 has an outer cylinder 30, and the outer cylinder 30 is provided with a flow path for cooling water, high pressure air, etc. inside the outer cylinder 30. A core 31 is fixed inside the outer cylinder 30. A high pressure air supply passage 32 and an exhaust passage 33 are provided in the core 31, and high pressure air supply pipes 3 are provided at both ends of the high pressure air supply passage 32.
4.35 are connected, and exhaust pipes 3 are connected to both ends of the exhaust passage 33.
6 and 37 are connected and fixed. The above high pressure air supply pipe 3
The base end (right side in the figure) of the high pressure air supply pipe 35 is connected to a high pressure air source (not shown), and the tip (left side in the figure) of the high pressure air supply pipe 35 is connected to the base end of the high pressure air supply passage 13 of the head section 3. The base end (left side in the figure) of the exhaust pipe 36 is connected to the tip of the exhaust passage 14 of the head section 3, and the exhaust pipe 3
The tip of 7 (on the right side in the figure) is connected to an exhaust device (not shown).

Further, cooling water supply pipes (cooling water passages) 38 and 39 are connected to both end surfaces of the core 31. The base end of the cooling water supply pipe 38 (on the right side in the figure) is connected to a cooling water supply source (not shown) that delivers cooling water at a nearly constant pressure, and the tip of the cooling water supply pipe 39 (on the left side in the figure) ) is connected to the base end of the cooling water passage 25 of the head section 3. The cooling water supply pipe 38 and the cooling water supply pipe 39 are connected via a flow control valve 40 provided within the core 31.

The flow control valve 40 is configured as follows.

A valve chamber 41 and an equilibrium chamber 42 are formed inside the core 31 . The equilibrium chamber 42 is located closer to the head portion 3 than the valve chamber 41 (on the left side in the figure), and the valve chamber 41 and the equilibrium chamber 42
are connected via the communication hole 43. The valve chamber 41 is connected to the cooling water supply pipe 38 via a communication hole 44,
A portion of the valve chamber 41 that is continuous with the communication hole 43 is a valve seat 45 having a tapered surface. This valve chamber 41 accommodates a spherical valve body 46 and a spring 47 that elastically biases the valve body 46 in a direction toward the valve seat 45 . On the other hand, a piston 48 is housed inside the equilibrium chamber 42 so as to be slidable along the axial direction of the outer cylinder 30, and the inner peripheral surface of the equilibrium chamber 42 and the piston 48 are sealed by a seal ring 49. There is. This piston 48 divides the equilibrium chamber 42 into two chambers 50, 51. A chamber 50 located closer to the head portion 3 than the piston 48 in the equilibrium chamber 42 communicates with the exhaust passage 33 through a communication hole 52, so that the exhaust passage 33 is formed on one end surface of the piston 48. The pressure of the flowing air acts on it. On the other hand, a chamber 51 located farther from the head portion 3 than the piston 48 in the equilibrium chamber 42 has a communication hole 5.
3 to the cooling water supply pipe 39. A rod portion 54 extends from the end surface of the piston 48 on the valve chamber 41 side. This rod portion 54 is loosely inserted into the communication hole 43, and its tip can protrude and retract into the valve chamber 41.

In the flow rate control valve 40, if air is not flowing through the exhaust passage 33, or even if air is flowing but the pressure of the air is extremely low, the force that pushes the piston 48 toward the valve chamber 41 may be completely reduced. Valve chamber 4 is absent or is very weak.
The valve body 46 is pressed against the valve seat 45 by the pressure of the cooling water supplied to the valve 1 and the elasticity of the spring 47, and the communication hole 43 is closed. As a result, no cooling water is supplied to the cooling water supply pipe 39. When the pressure of the air flowing through the exhaust passage 33 exceeds a predetermined value, the piston 48 is pushed toward the valve chamber 41, and the valve body 46 is pushed by the rod portion 54 and separated from the valve seat 45. As a result, The cooling water supply pipes 38 and 39 are connected, and cooling water is supplied to the cooling water supply pipe 39. Then, the piston 48 moves the piston 48 into the valve chamber 4.
It stops at a position where the force F1 pushing the piston 48 toward the valve chamber 41 and the force F pushing the piston 48 away from the valve chamber 41 are balanced. Here, the force F is the pressure of the air flowing through the exhaust passage 33 or the force that pushes the piston 48, and the force F is the force of the cooling water supplied from the cooling water supply pipe 38 to the valve chamber 41. The pressure or the force that pushes the rod portion 54 and the communication hole 4
3 into one chamber 51 of the equilibrium chamber 42 to push the piston 48, and the force of the spring 53 to push the piston 48 via the valve body 46. be. Since the pressure of the cooling water supplied to the valve chamber 41 is approximately constant, the valve opening degree of the flow rate control valve 40 is controlled by the pressure of the air flowing through the exhaust passage 33. As a result, when the air pressure is high, the valve opening becomes large, and the pressure of the cooling water flowing into the chamber 51 of the equilibrium chamber 42 becomes large, so that a large amount of cooling water is supplied to the cooling water supply pipe 39. become. On the contrary, when the air pressure decreases, the valve opening degree decreases, and the pressure of the cooling water flowing into the chamber 51 decreases, causing the cooling water supply pipe 3
9 will be supplied with only a small amount of cooling water.

When the dental handpiece 1 rotates the dental bur A to cut a tooth, the blade C of the rotating dental bur A is pressed against the tooth to be cut. When this happens, the rotational speed of the dental bur A is reduced due to resistance from the teeth, and at the same time, the injection holes E of the cooling water flow holes are blocked by the teeth, and the amount of cooling water sprayed is reduced. Decreasing the rotation speed of the dental bur A means that the rotation speed of the holder 10 also decreases, and when the rotation speed of the holder 10 decreases, the pressure loss of high-pressure air in the storage hole 6 increases. The pressure of the air discharged into the exhaust passage 14 decreases. Then, the flow rate control valve 40 operates to reduce its opening degree due to the pressure of this air, thereby reducing the amount of water supplied to the cooling water supply pipe 39. Therefore, the amount of cooling water supplied from the nozzle portion 22 of the dental handpiece 1 to the cooling water flow hole of the dental bur A decreases. In other words,
When the amount of cooling water jetted from the injection hole E of the dental bur A decreases, the amount of cooling water supplied from the dental handpiece 1 to the dental bur A can be reduced accordingly. It is possible to prevent cooling water from overflowing between the bearing 8 and the nozzle part 22, and as a result, the bearing 8
, 9 can be prevented from rusting and causing malfunction.

It is also conceivable that the amount of cooling water sprayed decreases without decreasing the number of rotations of the dental bur A during cutting of teeth. For example, a case may occur in which the dental bur A is rotated while lightly touching the tooth, but the injection hole E of the dental bur A becomes clogged with tooth chips. Also at this time, the amount of cooling water supplied from the dental handpiece 1 to the dental bur A can be reduced. That is, when the actual opening area of the nozzle hole E is narrowed,
The pressure of the cooling water in the cooling water passage 25 increases, and therefore the pressure in the chamber 51 of the flow control valve 40 increases. Then, even if the pressure of the air in the exhaust passage 33 does not change, the piston 48 is moved away from the valve chamber 41 by the pressure of the cooling water in the chamber 51, and the flow rate control valve 40 changes its opening degree. This is because it operates to make it smaller.

Next, the second invention will be explained based on FIG.

Note that the head portion 3 of the dental handpiece 1 is no different from the first invention, so a description thereof will be omitted.

FIG. 4 is a longitudinal sectional view of the main part of the arm portion 2, and corresponds to FIG. 3 of the first invention. In the following explanation, the third
Components having the same features as those in the drawings will be described with the same reference numerals. Third
The arm portion 2 in the figure and the arm portion 2 in FIG. 4 have the same structure in the following points. That is, ■Outer R of arm portion 2
30, the core 31 is fixed to the core 31; An exhaust pipe 36 connected to the exhaust passage 14 of the head part 3 and an exhaust pipe 37 connected to an exhaust device are connected by a high-pressure air supply passage 32 provided in the core 31. The points connected by the exhaust passage 33, ■ the cooling water supply pipe 3 connected to the cooling water supply source;
8 and 8, a cooling water supply pipe 39 connected to the cooling water passage 25 of the do portion 3 is connected to each end surface of the core 31.

The arm portion 2 of FIG. 4 differs from the arm portion 2 of FIG. 3 in the flow control valve 60 that connects the cooling water supply pipes 38, 39. The flow control valve 60 is configured as follows. A valve chamber 61 is formed inside the core 31, and the valve chamber 61 is connected to the cooling water supply pipe 3 through a communication hole 6263.
8.39 is connected. The communication hole 6 in the valve chamber 61
The portion connected to 2 is a valve seat 64 made of a Taber surface. The valve chamber 61 includes a spherical valve body 65 and a spring 66 that elastically biases the valve body 65 in a direction toward the valve seat 64.
is accommodated. Therefore, when cooling water is not being supplied to the cooling water supply pipe 38, the valve body 65 seats on the valve seat 64 and closes the communication hole 62.

When cooling water at a predetermined pressure is supplied to the cooling water supply pipe 38,
The pressure of the cooling water causes the valve body 65 to be separated from the valve seat 64, opening the valve, and cooling water is supplied to the cooling water supply pipe 39. In this valve open state, the valve body 65 is moved away from the valve seat 64 by the force of the spring 66 that presses the valve body 65 in the direction toward the valve seat 64 and by the pressure difference of the cooling water before and after the valve body 65. The valve body 65 is stopped at a position where these forces are balanced, and the valve opening degree is determined. Here, since the pressure of the cooling water supplied to the cooling water supply pipe 38 is approximately constant, the valve opening degree of the flow rate control valve 60 is controlled by the pressure of the cooling water flowing through the cooling water supply pipe 39. Become. As a result, this control valve 60 operates to reduce the valve opening when the pressure of the cooling water in the cooling water supply pipe 39 is high.
When the pressure of the cooling water in the cooling water supply pipe 39 is low, the valve opening is increased.

Dental nose 1 equipped with the above flow control valve 60
In this case, if the injection hole E of the dental bur A is blocked by teeth or the injection hole E is clogged with tooth chips, the amount of cooling water jetted from the dental bur A decreases. Since the pressure of the cooling water in the cooling water passage 25 increases, the pressure of the cooling water in the cooling water supply pipe 39 also increases. Then, as described above, the flow control valve 60 operates in the closing direction, and the amount of cooling water supplied to the three cooling water supply pipes decreases, which in turn causes the flow of the dental bur A from the nozzle portion 22 of the dental handpiece L. The amount of cooling water supplied to the cooling water distribution holes decreases. That is, in the dental handpiece 1 according to the second invention, as well as in the dental handpiece 1 according to the first invention, when the amount of cooling water jetted from the injection hole E of the dental bur A decreases,
Accordingly, the amount of cooling water supplied from the dental handpiece 1 to the dental bur A can be reduced, thereby preventing cooling water from overflowing from between the hole 23 of the cap 20 and the nozzle part 22. It is possible to prevent the bearing 8゜9 from rusting and causing malfunction.
This effect is achieved.

This invention is not limited to the above-described embodiments, and various embodiments can be adopted.

For example, in the dental handpieces of the first invention and the second invention, the non-contact type 71 mechanism provided between the shank part of the dental bur and the cooling water injection part of the dental handpiece is The structure is not limited to one that utilizes the pump action as in the above-mentioned embodiment, but for example,
As disclosed in Japanese Patent No. 58, an air seal structure may be used in which compressed air is allowed to flow into a non-contact gap from the outside.

Further, the valve body of the flow control valve in the dental handpiece of the first invention and the second invention is not limited to a spherical shape, but may be needle-shaped, and furthermore, the valve structure of the flow control valve may be modified. A diaphragm type may also be used.

Further, the driving fluid of the driving device in the dental handpiece of the first invention is not limited to air, and may be water or the like.

Moreover, in the dental handpiece of the second invention, the valve opening degree of the flow control valve is controlled by the pressure of the cooling water on the secondary side, so that the driving device for rotationally driving the dental burr is controlled by the pressure of the cooling water on the secondary side. is not limited to a fluid-driven type, and other drive types such as motor drive are also possible.

[Effects of the Invention] As explained above, according to the present invention, when the amount of cooling water jetted from the dental bur decreases, the flow of water from the cooling water injection part of the dental handpiece to the cooling water distribution hole of the dental bur is reduced. As a result, the excellent effect of preventing cooling water from overflowing into the dental handpiece can be achieved.

[Brief explanation of the drawing]

The drawings from FIG. 1 to FIG. 4 show an embodiment of the invention of this application, in which FIG. 1 is an external front view of the dental handpiece, FIG. 2 is an enlarged vertical cross-sectional view of the head part, FIG. 3 is an enlarged sectional view of the main part of the arm part in the first invention, and FIG. 4 is an enlarged sectional view of the main part of the arm part in the second invention. 1... Dental handpiece, 10... Holder (
drive device), 13... high pressure air supply passage, 1
4...Exhaust passage, 20...Cap (seal mechanism)
, 21... pump chamber (seal mechanism), 22...
Nozzle section (cooling water injection section), 24... Screw member (seal mechanism), 25... Cooling water passage, 32. High pressure air supply passage, 33... Exhaust passage, 34.35
...High pressure air supply pipe, 36.37...Exhaust pipe, 3
839... Cooling water supply pipe (cooling water passage), 40... Flow rate control valve, 46... Valve body, 60... Flow rate control valve, 65
...Valve body, A...Dental bar D...Cooling water flow hole.

Claims (2)

[Claims] (1) A dental handpiece in which a driving device driven by a fluid is built in, and the driving device rotates a dental bur having a cooling water flow hole, (a) a non-contact sealing mechanism is used to connect the dental (b) a cooling water passage connecting the cooling water injection part and a cooling water supply source; (c) a flow control valve provided in the middle of the cooling water passage, controlled by the fluid after driving the drive device, and adjusting the valve opening according to the magnitude of the pressure of the fluid; Dental handpiece. (2) A dental handpiece with a built-in drive device for rotating a dental bur having a cooling water flow hole, (a) a dental handpiece connected to the dental bur via a non-contact sealing mechanism, (b) A cooling water passage connecting the cooling water injection part and the cooling water supply source, (c) A middle part of the cooling water passage. A dental handpiece, comprising: a flow control valve, which is installed in the flow control valve and adjusts the valve opening according to the magnitude of the cooling water pressure on the secondary side.