JPH08280717A - Motor-driven toothbrush - Google Patents

Abstract

PURPOSE: To provide a motor-driven toothbrush capable of obtaining the reciprocating motion of a large stroke without enlarging a motion conversion mechanism. CONSTITUTION: The motion conversion mechanism for changing the rotary motion of a motor 12 to the reciprocating motion of a driving shaft 16 is provided with a pinion gear 18 attached to the rotary shaft of the motor 12, the idle gear 22 of two stages engaged with the pinion gear 18, a face gear 24 engaged with the idle gear 22, an eccentric pin 26 attached on the back surface side of the face gear 22 and a cam 28 provided on the end part of the driving shaft 16 and the eccentric pin 26 is rotatably and slidably fitted to an elliptic groove 28b formed on the back side of the cam 28. Thus, by the rotation of the motor 12, the eccentric pin 26 is eccentrically rotated and the driving shaft 16 performs the reciprocating motion back and forth accompanying it.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electric toothbrush.

[0002]

2. Description of the Related Art Conventionally, an electric toothbrush is generally provided between a motor, a drive shaft to which a brush body (toothbrush) is connected at one end, and the motor and the drive shaft. And a motion conversion mechanism for converting into a reciprocating motion. The motion conversion mechanism has a structure as shown in FIG. 10, for example. According to this, the rotation of the motor 80 is transmitted to the face gear 82 that meshes with the pinion gear 81 attached to the rotation shaft, and the rotation is decelerated. The eccentric pin 83 protrudingly provided on the gear portion side of the face gear 82 is an oval formed on the back side of a cam 85 provided at the other end of the drive shaft 84 to which a toothbrush (not shown) is connected at one end. Since it is fitted in the groove (not shown) so as to be rotatable and slidable (however, the eccentric pin 83 is shown slightly larger than the cam 85 in the drawing), the eccentric rotation of the eccentric pin 83 causes the rotational movement. The linear reciprocating motion of the drive shaft 84 is converted, and the toothbrush at one end of the drive shaft 84 reciprocates back and forth. The face gear 82
The shaft 86 is rotatably supported and is inserted into the oval hole 85a of the cam 85.

[0003]

In the electric toothbrush having the above-described motion converting mechanism, when the stroke of the toothbrush (that is, the drive shaft 84) is small, the bristle tips of the toothbrush hardly move with respect to the tooth surface. It is known that the cleaning effect on the surface becomes smaller, but the plaque removing effect becomes higher as the stroke becomes longer (see FIG. 9). On the contrary, as the stroke becomes longer, the stroke length becomes 10 m, for example.
It is also known that the gum is easily damaged when it is more than m. For this reason, it is necessary for the plaque removal effect to increase the stroke length to the extent that the gums are not damaged, but in order to obtain a large stroke, that is, in order to increase the reciprocating motion of the drive shaft 84, eccentricity is required. Not only the size of the pin 83 (that is, the face gear 82) becomes large, but also the face gear 8
Since 2 is larger than the eccentric pin 83, the entire motion conversion mechanism becomes large. However, due to the size of the electric toothbrush, there is a space limitation, and the stroke of the drive shaft 84 cannot be made too large.

Further, there is an electric toothbrush capable of adjusting the number of revolutions of the motor (reciprocating motion of the toothbrush) in three stages of "fast, normal, and slow". The rotation speed of the motor is fixed, for example, at "fast" 3000 cp
m, "normal" 2500 cpm, "slow" 200
It is 0 cpm, and the user sets the rotation speed to his or her preference and uses it. However, since the respective rotation speeds are always constant, it is not possible to polish at the rotation speed of one's liking according to the individual's tooth arrangement, tooth profile or tooth brushing site. Moreover, when the polishing pressure is increased, the rotation speed, which should be constant, tends to decrease, and in this case, it is impossible to polish with a high polishing pressure while maintaining the constant rotation speed.

Accordingly, the present invention has been made in view of the above problems, and it is a first object of the present invention to provide an electric toothbrush capable of reciprocating a large stroke without increasing the size of the motion converting mechanism. The purpose of. Second of the present invention
It is an object of the present invention to provide an electric toothbrush that can be brushed at a rotation speed of one's liking regardless of the polishing pressure.

[0006]

In order to achieve the first object, an electric toothbrush according to claim 1 of the present invention is a motor, a drive shaft having a brush body connected to one end, a motor and a drive shaft. A motion converting mechanism which is interposed between the motor and a rotary shaft of the motor and converts the rotary motion of the motor into reciprocating motion of the drive shaft, wherein the motion converting mechanism is a pinion gear attached to the rotary shaft of the motor; A face gear that meshes with the pinion gear; an eccentric pin attached to the back side of the face gear; and a cam provided on the other end of the drive shaft,
The eccentric pin is rotatably slidably inserted into an oval portion formed on the cam.

In order to further reduce the size, an electric toothbrush according to a second aspect of the present invention is provided with a motor, a drive shaft having a brush body connected to one end, and the motor and the drive shaft. A motion conversion mechanism for converting a rotational motion of a motor into a reciprocating motion of a drive shaft, wherein the motion conversion mechanism includes a pinion gear attached to a rotary shaft of the motor, and an idle gear meshed with the pinion gear. A face gear that meshes with the idle gear; an eccentric pin attached to the back side of the face gear; and a cam provided at the other end of the drive shaft. The eccentric pin is rotatably slidably inserted.

In order to achieve the second object, an electric toothbrush according to a third aspect of the present invention has a motor, a drive shaft having a brush body connected to one end, and a motor and the drive shaft. A motor drive control means for controlling the drive of the motor, and a motor drive control means for detecting an operating pressure. And a rotation speed adjusting means for sending a signal of a desired motor rotation speed.

[0009]

In the electric toothbrush according to the first aspect of the invention, the pinion gear attached to the rotary shaft of the motor meshes with the face gear, and the eccentric pin projecting on the back side of the face gear is attached to the other end of the drive shaft. By rotating and sliding within the elliptical portion formed on the provided cam, the rotational movement of the motor is converted into linear reciprocating movement of the drive shaft, and the brush body (toothbrush) at one end of the drive shaft reciprocates back and forth. .

According to this structure, the eccentric pin is provided on the back side of the face gear and the pinion gear of the rotary shaft of the motor meshes with the face gear, so that a large stroke on the drive shaft side can be obtained conventionally. Compared with this, it is not necessary to enlarge the shape of the eccentric pin (that is, the face gear), the space required for the motion conversion mechanism can be minimized and the size can be reduced, thereby reducing the size and cost of the electric toothbrush. Can be realized.

In the electric toothbrush according to claim 2, in addition to the structure according to claim 1, since the idle gear is interposed between the pinion gear and the face gear, a large stroke on the drive shaft side can be obtained. In comparison with the electric toothbrush according to claim 1, it is possible to further minimize the space required for the motion conversion mechanism, and to achieve further miniaturization, thereby realizing further miniaturization and cost reduction of the electric toothbrush. .

In the electric toothbrush according to the third aspect, the user operates the rotation speed adjusting means to select a desired rotation speed, and the rotation speed is transmitted to the motor drive control means, and the motor drive control means is operated. Adjust the motor speed to its selected value. Therefore, the user can freely change the rotation speed without depending on the brushing pressure and can brush the teeth at a desired rotation speed.

[0013]

EXAMPLES The electric toothbrush of the present invention will be described below based on examples. First, an external perspective view of an embodiment of an electric toothbrush according to claim 1 is shown in FIG. 1, a schematic configuration diagram of a motion conversion mechanism thereof is shown in FIG. 2, and an exploded perspective view thereof (however, in this embodiment, the idle gear 22 is (Not used) is shown in FIG.
In this electric toothbrush, the motor 1 is installed in the housing 10.
2, a battery (not shown) as a power source for driving the motor 12, a drive shaft 16 to which a brush body (toothbrush, not shown) is connected at one end, and a drive shaft 16 between the motor 12 and the drive shaft 16. And a motion conversion mechanism that converts the rotational motion of the motor 12 into the reciprocating motion of the drive shaft 16.

The motion converting mechanism as a feature of the first aspect is mounted on a mechanical frame (not shown) provided in the housing 10. Rotating shaft 12a of the motor 12
The pinion gear 18 attached to the gear meshes with the face gear 24 rotatably supported by the mechanical frame. The face gear 24 is attached to a shaft 24a that is rotatably fixed to the mechanical frame, and an eccentric pin 26 is integrally fixed to the rear surface side (the side opposite to the gear portion side) of the shaft 24a.
On the other hand, a flat cam 28 provided at the other end of the drive shaft 16
Is formed with an elliptical hole 28a through which the shaft 24a is inserted, and an oblong groove 28b into which the eccentric pin 26 is rotatably slidably fitted is formed on the back side of the cam 28 []. FIG. 5B)]. Here, the oval hole 28a and the oval groove 2
8b constitutes an elliptical portion through which the eccentric pin 26 is rotatably slidably inserted. However, in FIG. 5, for convenience, the eccentric pin 26 is shown slightly larger than the cam 28, but in reality, the eccentric pin 26 fits into the elliptical groove 28b on the back side of the cam 28, and within the elliptical groove 28b. It is a size that can be rotated.

In this electric toothbrush, when a power switch (not shown) is turned on, the rotation of the motor 12 is transmitted to the face gear 24 through the pinion gear 18 and the eccentric pin 26 of the cam 28 is moved by the motion converting mechanism. Oval groove 2
8b is displaced in the front-rear direction while rotating eccentrically, whereby the drive shaft 16 reciprocates back and forth, and the toothbrush at the tip of the drive shaft 16 operates. In this electric toothbrush, the portion of the motion conversion mechanism can be formed into a flat shape, and the size can be reduced.

Next, a cross-sectional view of an embodiment of the electric toothbrush according to claim 2 is shown in FIG. 3, and an enlarged view of a main part of the motion converting mechanism is shown in FIG. 4 [top view (a), side view (b)]. FIG. 5 shows an exploded perspective view thereof. However, the same elements as those in the above embodiment are designated by the same reference numerals. In this electric toothbrush, a motor 12, a battery 14 as a power source for driving the motor 12, a drive shaft 16 to which a brush body is connected at one end, and a motor 12 are provided in the housing 10. Was set up,
A motion conversion mechanism that converts the rotational motion of the motor 12 into the reciprocating motion of the drive shaft 16.

The motion conversion mechanism, which is a feature of the second aspect, is attached to a mechanical frame 11 provided in the housing 10. The pinion gear 18 attached to the rotary shaft 12 a of the motor 12 meshes with a two-stage idle gear 22 arranged in parallel with the pinion gear 18. The idle gear 22 is a shaft 22 a fixed to the mechanical frame 11 so as to be rotatable in parallel with the rotation shaft 12 a of the motor 12.
The large gear 20 has a large number of teeth and is meshed with the pinion gear 18, and a small gear 21 having a smaller number of teeth than the large gear 20, and the small gear 21 meshes with the face gear 24.

The face gear 24 has the same structure as the shaft 2 as described above.
It is attached to a shaft 24a that is rotatably fixed to the mechanical frame 11 perpendicularly to 2a, and an eccentric pin 26 is integrally fixed to the back side (the side opposite to the gear side) of the shaft 24a. Further, an oblong hole 28a is formed through the flat cam 28 at the other end of the drive shaft 16, and an oblong groove 28b is formed on the back side of the cam 28.

The drive shaft 16 is reciprocally supported by a ball bearing 30 attached to the mechanical frame 11. The tip of the drive shaft 16 penetrates through the center of the waterproof rubber 32 and projects to the outside of the housing 10. . A toothbrush (not shown) is attached to the protruding portion of the drive shaft 16. In addition, the power switch 3 is provided at a proper position of the housing 10.
4 are provided.

In this electric toothbrush, the power switch 34
When turned on, the motion conversion mechanism causes the motor 12
Is transmitted to the face gear 24 through the pinion gear 18 and the idle gear 22, and the eccentric pin 26 causes the cam 2 to move.
8 is displaced in the longitudinal direction while being eccentrically rotated in the elliptical groove 28b, the drive shaft 16 reciprocates back and forth, and the toothbrush at the tip of the drive shaft 16 operates. This electric toothbrush can be made smaller than the electric toothbrush according to claim 1.

FIG. 6 is a sectional view showing an embodiment of the electric toothbrush according to the present invention. In this electric toothbrush, a motor 42 and a battery 44 as a power source are provided in a housing 40.
A drive shaft 46 to which a toothbrush is attached at one end, and a motion conversion mechanism that converts the rotational motion of the motor 42 into the reciprocating motion of the drive shaft 46 are provided. This motion conversion mechanism
The rotation shaft 42a of the motor 42 is publicly known.
The gear 48 attached to the gear 48, the gear 48 meshes with the gear 48, and the shaft 50a is attached to the mechanical frame 41 provided in the housing 40.
The crown gear 50 and the like are rotatably supported by. The drive shaft 46 is supported by a ball bearing 52 so as to be capable of reciprocating, and its tip penetrates through the center of the waterproof rubber 54 and projects to the outside of the housing 40.

The characteristic feature of this electric toothbrush is that it comprises motor drive control means for controlling the rotational drive of the motor 42, and rotation speed adjustment means for detecting an operating pressure and sending a signal of a desired rotation speed to the motor drive control means. That is, in this embodiment, these means are constituted by circuits, switches and the like. The circuit board 56 arranged in the housing 40 includes:
As shown in FIG. 7, a motor drive circuit (motor drive control means) 60, which is connected to the motor 42 and includes, for example, a one-chip microcomputer in which a predetermined program is stored, and a power supply circuit 61 for controlling the power supply.
And a rotation speed detecting means 62 for detecting the rotation speed of the motor 42.
And a rotation speed adjusting means 58 for adjusting the rotation speed of the motor 42.
And are installed. The power circuit 61 is a power switch 64
Is connected to the power source 44 via the motor, and the rotation speed adjusting means 58 is connected to the motor drive circuit 60. It should be noted that the rotation speed detection means 62 generally detects the rotation speed by using a magnetic resistance element, a hall element, or the like in the motor 42, and details thereof will be omitted here.

The rotation speed adjusting means 58, in this embodiment,
A sensor 63 that detects an operating pressure and sends a signal of a desired motor rotation speed to the motor drive circuit 60.
have. Specifically, it is a pressure sensitive switch 58 provided at an appropriate position of the housing 40. Pressure sensitive switch 58
Is well known, and the resistance value increases when the switch is strongly pressed, and the resistance value decreases when the switch is weakly pressed. The resistance value of the pressure sensitive switch 58 is detected and input to the motor drive circuit 60, and the motor drive circuit 60 changes the voltage applied to the motor 42 according to the resistance value. That is,
When the resistance value of the pressure sensitive switch 58 increases, the motor 42
When the applied voltage rises and the rotation speed of the motor 42 rises, and conversely the resistance value decreases, the applied voltage falls and the rotation speed drops.

Actually, the rotation speed of the motor 42 is, for example, as shown in FIG.
As shown in, when the pressure-sensitive switch 58 is not pressed, the initial low-speed rotation N2 occurs, and as the pressure-sensitive switch 58 is strongly pressed, the rotation speed increases, and the rotation speed N1 at a certain pressing force becomes Maximum speed. Therefore, the user can brush the teeth at a desired rotation speed between the rotation speeds N2 and N1 according to the tooth brushing site by adjusting the pressure of the pressure sensitive switch 58 during brushing.

[0025]

In the electric toothbrush according to the first aspect of the present invention, the motion converting mechanism for converting the rotational motion of the motor into the reciprocating motion of the drive shaft is provided with the eccentric pin on the back side of the face gear, and the face gear is also provided. Since it is configured by meshing the pinion gear of the rotation shaft of the motor, it is not necessary to increase the shape of the eccentric pin (that is, the face gear) in comparison with the conventional one to obtain a large stroke on the drive shaft side. The space required for the motion conversion mechanism can be minimized to achieve miniaturization, which can realize miniaturization and cost reduction of the electric toothbrush.

In the electric toothbrush according to a second aspect of the invention, the motion converting mechanism is configured by interposing an idle gear between the pinion gear and the face gear in addition to the configuration of the first aspect, so that the drive shaft In comparison with the electric toothbrush according to claim 1 for obtaining a large stroke on the side, it is possible to further minimize the space required for the motion converting mechanism, thereby achieving further miniaturization of the electric toothbrush.・ Low cost can be realized.

In the electric toothbrush according to claim 3 of the present invention, the user operates the rotation speed adjusting means to select a desired rotation speed, and the rotation speed is transmitted to the motor drive control means. Since the motor drive control means adjusts the rotation speed of the motor to the selected value, the user can freely change the rotation speed without depending on the tooth brushing pressure, and can brush the teeth at a desired rotation speed.

[Brief description of drawings]

FIG. 1 is an external perspective view showing an embodiment of the electric toothbrush according to claim 1.

FIG. 2 is a schematic configuration diagram showing a motion conversion mechanism in the embodiment.

FIG. 3 is a cross-sectional view showing an embodiment of the electric toothbrush according to claim 2.

FIG. 4 is an enlarged top view (a) and a side view (b) of an essential part of the motion conversion mechanism in the embodiment.

FIG. 5 is an exploded perspective view of a motion converting mechanism in the embodiment.

FIG. 6 is a sectional view showing an embodiment of the electric toothbrush according to claim 3;

FIG. 7 is a block circuit diagram showing a circuit example of the same embodiment.

FIG. 8 is a graph showing the relationship between the pressing force of the pressure sensitive switch and the rotation speed of the motor in the example.

FIG. 9 is a graph showing the relationship between the stroke length of an electric toothbrush and the effect of removing plaque.

FIG. 10 is an exploded perspective view of a motion conversion mechanism in an electric toothbrush according to a conventional example.

[Explanation of symbols]

 12, 42 Motor 16, 46 Drive shaft 18 Pinion gear 22 Idle gear 24 Face gear 26 Eccentric pin 28 Cam 28a Oval hole 28b Oval groove 58 Pressure sensitive switch (rotation speed adjusting means) 60 Motor drive circuit (motor drive control) means)

Claims (3)

[Claims] 1. A motor, a drive shaft to which a brush body is connected at one end, and a motion conversion mechanism which is interposed between the motor and the drive shaft and which converts the rotational motion of the motor into reciprocating motion of the drive shaft. In the electric toothbrush provided with, the motion conversion mechanism includes a pinion gear attached to a rotation shaft of the motor, a face gear meshing with the pinion gear, an eccentric pin attached to a back side of the face gear, and the drive shaft. An electric toothbrush having a cam provided at the other end thereof, and the eccentric pin being rotatably slidably inserted through an oval portion formed on the cam. 2. A motor, a drive shaft to which a brush body is connected at one end, and a motion conversion mechanism interposed between the motor and the drive shaft for converting rotational motion of the motor into reciprocating motion of the drive shaft. In the electric toothbrush provided with, the motion conversion mechanism includes a pinion gear attached to a rotation shaft of the motor, an idle gear that meshes with the pinion gear, a face gear that meshes with the idle gear, and a rear surface of the face gear. An eccentric pin attached to the drive shaft; and a cam provided on the other end of the drive shaft. The eccentric pin is rotatably slidably inserted into an oval portion formed on the cam. Electric toothbrush to do. 3. A motor, a drive shaft to which a brush body is connected at one end, and a motion conversion mechanism which is interposed between the motor and the drive shaft and which converts the rotational motion of the motor into reciprocating motion of the drive shaft. An electric toothbrush provided with the motor drive control means for controlling the drive of the motor, and a rotation speed adjustment means for detecting an operating pressure and sending a signal of a desired motor rotation speed to the motor drive control means. electric toothbrush.