Electric toothbrush

Abstract

To provide an electric toothbrush that is capable of a scrubbing method with vibration including brush tip high-speed vibration and the whole brush including direct advance reciprocation using a single motor.SOLUTION: An electric toothbrush includes: a housing 4; a motor 24 fitted to the housing 4 via a motor holding member 23 and including an eccentric weight 20; transfer mechanisms 31, 32 for transferring drive force of the motor 24; and a conversion mechanism 30 for converting rotation motion of the drive force into a direct advance reciprocation. The conversion mechanism 30 is fixed to the housing in a position different from the position of the motor holding member 23.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an electric toothbrush. [Background technology]

[0002] In recent years, as the effects of periodontal disease on the entire body have come to be elucidated, attention has been focused on maintaining healthy teeth and gums, and interest in oral care has increased.

[0003] The purpose of tooth brushing is to remove dirt from the tooth surface, periodontal pockets, and between the teeth. In particular, to reach the small gaps, it is important to move the toothbrush in small horizontal movements (in the direction of the teeth).

[0004] However, it is difficult to continuously perform quick, constant-speed, constant-travel strokes in a horizontal direction when brushing teeth manually, which leads to uneven brushing.

[0005] Most electric toothbrushes use a method in which the vibration of a motor is transmitted to the brush, causing the brush bristles to vibrate at high speed. It has been reported that the amount of plaque removed is proportional to the number of strokes made by the brush, and it is said that this method can achieve an overwhelming number of strokes compared to manual brushing, and that faster speeds are more effective at removing plaque.

[0006] Moreover, Patent Document 1 discloses an electric toothbrush that moves the brush back and forth in a straight line. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2000-279432 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the electric toothbrush described in Patent Document 1, although it performs a stroke motion (linear reciprocating motion), it does not vibrate the brush.

Means for Solving the Problems

[0009] In order to solve the above problems, the electric toothbrush of the present invention In order to reduce the loss of the motor vibration by the stroke mechanism, the motor unit and the stroke mechanism unit are separated. The connection between the motor unit and the stroke mechanism unit is a worm gear attached to the motor output shaft and a wheel of the stroke mechanism unit, and the motor unit and the stroke mechanism unit are each fixed to the housing.

Effects of the Invention

[0010] The present invention can improve the plaque removal power and shorten the brushing time by vibrating the brush at high speed while performing a linear reciprocating motion.

Brief Description of the Drawings

[0011]

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Mode for Carrying Out the Invention

[0012] <First Embodiment> FIG. 1 is an exploded perspective view of an electric toothbrush according to a first embodiment of the present invention, and is composed of a replaceable brush 2 attached to the tip of a housing 4 and a cover cap 1 that covers the brush. A switch button 3 is provided on the housing 4, and input such as turning the power on / off and switching modes is possible.

[0013] A stroke unit 5 is provided inside the housing 4 and is fixed to the housing 4 by screws 6a and 6b. Further, it has a motor unit 7 that generates the driving force of the stroke unit 5, and is fixed to the housing 4 by screws 8a and 8b. That is, the stroke unit 5 and the motor unit 7 are fixed to the housing 4 at different positions.

[0014] The power of the motor unit 7 is supplied from dry batteries 14a and 14b via electrical connection terminals 9a and 9b, and the electrical connection terminals 9a and 9b are fixed to the battery case 11 by screws 10a and 10b.

[0015] The battery case 11 is attached with elastic members 13a and 13b to prevent the self-weight drop of the dry battery. The battery case 11 is fixed to the housing 4 by screws 12a and 12b. The dry battery 14a and the dry battery 14b are electrically connected by an electrical connection terminal 15 and fixed to the lid 17 by a screw 18. A waterproof rubber 16 is attached to the lid 17.

[0016] Figure 2 is an exploded perspective view of the motor unit 7. A worm gear 19, which is a transmission member for transmitting the driving force for stroking the replaceable brush 2, is attached to the output shaft of the motor 24. The output shaft of the motor 24 is further provided with an eccentric weight 20 for obtaining the positive vibration of the motor 24. The motor 24 is fixed to the motor mounting base 23 (motor holding member) by screws 25a and 25b on the motor mounting surface which is the end face on the output shaft side. A power switch 21 is soldered to the motor mounting base 23 together with the motor 24 to an electrical wiring member (FPC: Flexible Print Circuit) 22. Note that the solder is not shown.

[0017] Figure 3 is an exploded perspective view of a stroke unit 5 (conversion mechanism holding part), which is a mechanism part for stroking the replaceable brush 2. The replaceable brush 2 is attached, and a stroke shaft 26 that makes a straight reciprocating motion, that is, a stroke, is attached to a stroke guide 28 that has a holding of the stroke shaft 26 and a straight guide for the straight stroke. A waterproof rubber 27 is provided on the stroke shaft 26 to prevent water from entering through the gap between the stroke shaft 26 and the stroke guide 28 during the stroke operation. It has a stroke holder 29 for holding the stroke guide 28, and the stroke guide 28 is attached to the stroke holder 29 by screws 38a and 38b.

[0018] The stroke operation of the brush 2 is realized by a swing lever 30 (conversion mechanism) that makes a swing motion so as to convert the rotational motion into a straight reciprocating motion. The swing lever 30 has a rotation shaft 35a serving as a swing fulcrum inserted therethrough and is attached to the stroke holder 29 by retaining rings 36a and 36b.

[0019] The driving force transmitted from the worm gear 19 in FIG. 3 is transmitted by a two-stage gear 31 that meshes with the worm gear 19. The two-stage gear 31 also meshes with a one-stage gear 32. The rotation shaft 35b of the two-stage gear 31 is attached to the stroke holder 29 by a retaining ring (not shown).

[0020] The driving force transmitted by using the two-stage gear 31 and the one-stage gear 32 as a speed reduction mechanism (transmission mechanism) is attached so as to protrude to a desired position away from the rotation center of the one-stage gear 32, and is transmitted to the swing lever 30 by a connecting pin 33 that fits into a hole 30a of the swing lever 30. The swing width of the swing lever 30, that is, the stroke length of the brush 2, is determined by the distance between the rotation center of the one-stage gear 32 and the desired position where the connecting pin 33 is provided.

[0021] A stroke pin 34 that fits through a sliding hole 30b (see FIG. 5) provided in the swing lever 30 is also inserted into the stroke shaft 26, receives the swinging motion of the swing lever 30, and transmits it to the stroke shaft 26. The retaining ring 37 is a member that prevents the fitting of the stroke pin 34 from coming off.

[0022] FIG. 4 is a view showing a motor mounting base 23 that is a housing mounting portion of the motor unit 7. It is fixed to the housing by fixing arms 23a and 23b with screws 8a and 8b. The fixing arms 23a and 23b are formed in an arm shape so as not to suppress the shaking due to the vibration of the motor 24. In other words, the motor unit 7 has an arm portion that extends in a direction parallel to the output shaft of the motor from the portion fixed by the screws 8a and 8b. Further, since the motor shaking is pivoted on the motor mounting surface, the mounting position on the housing is set to be equal to the motor mounting surface or on the tip side of the output shaft so as not to interfere with the motor shaking. Therefore, a large shaking by the motor, that is, a large amplitude, can be obtained.

[0023] FIG. 5 is a diagram showing a stroke mechanism including a part of the motor unit 7 and the stroke unit 5, and only shows the members involved in the stroke operation. The motor 24 rotates continuously in the clockwise direction (direction of arrow 40) when viewed from the direction of arrow 39. The rotational output of the motor 24 rotates the single-stage gear 32 via the two-stage gear 31 from the worm gear 19 fixed to the output shaft.

[0024] A connecting pin 33 for converting the swinging motion, which is fixed to the single-stage gear 32, is fitted into the sliding hole 30a of the swing lever 30. The rotational motion is converted into a swinging motion by the connecting pin 33 that rotates together with the single-stage gear 32, and the swing lever 30 swings as shown by arrow 41 about the rotation axis 35a.

[0025] The swinging motion is converted into a linear motion and transmitted to the stroke pin 34 fitted into the sliding hole 30b, and the stroke shaft 26 is guided by the linear guiding portion of the stroke guide 28 shown in FIG. 2 to perform a linear reciprocating motion. When the motor 24 rotates in the direction opposite to arrow 40, only the rotational direction of each gear is reversed, and the overall operation is the same. That is, the rotation of the motor 24 is converted into the swinging motion of the swing lever, and further into the linear reciprocating motion of the stroke shaft 26, enabling the linear reciprocating motion of the stroke shaft 26 with the one-way rotation of the motor 24.

[0026] As described above, since the stroke unit 5 and the motor unit 7 are connected, they are mechanically connected up to the brush tip. That is, the vibration generated by the eccentric weight 20 attached to the output shaft of the motor 24 is transmitted through the motor unit 7 and the stroke unit 5 to the brush 2. At this time, by having the fixed arms 23a and 23b, the influence of suppressing the vibration of the housing 4 when the user grips the housing 4 by hand is suppressed, and the vibration is easily transmitted through the internal structure of the housing 4 to the brush 2.

[0027] <Second Embodiment> Hereinafter, an electric toothbrush according to a second embodiment of the present invention will be described. In the following description, the same reference numerals may be used for the same configurations as those in the first embodiment, and the description thereof may be omitted. Although it will be described as the second embodiment, the same operations and effects as those described below will occur for the parts common to the first embodiment, and the different parts can also be used in combination.

[0028] As in the electric toothbrush described in the first embodiment, in an electric toothbrush that vibrates, it is important how stably it can be held by hand.

[0029] However, a large force is required for stable holding, so there may be fatigue in the hand and fingers, and it may not be possible to ensure a certain toothbrushing time. The instability of the pressing force of the toothbrush against the teeth leads to uneven brushing.

[0030] Many electric toothbrushes have products with a handle portion having a cross-sectional shape of a substantially perfect circle or a substantially regular polygon. Therefore, there is a demand for a product provided with a handle portion that is easy to hold by hand and fingers and can be held with a small force.

[0031] In addition, the placement area of the electric toothbrush before and after toothbrushing, especially the washbasin at the workplace such as outside the home or the company, is often narrow, and it is also necessary that there are no restrictions on the placement method.

[0032] By the way, in order to obtain tooth plaque removal and a vibration feeling, there is a demand to increase the amplitude, which is the swing width of the toothbrush bristles. A large number of methods generate vibration by mounting an eccentric weight on the output shaft of the motor. If the motor torque is large, it is possible to increase the eccentric weight, that is, the eccentricity amount, without reducing the rotation speed, that is, it is possible to increase the amplitude.

[0033] There is also a demand for a product that can mount a motor with improved torque without increasing the external dimensions.

[0034] In order to solve these requirements, the electric toothbrush of the present embodiment is characterized in that the cross-sectional shape of the handle portion of the housing is substantially elliptical, and the major axis of the substantially elliptical shape is 1.5 times or more the minor axis.

[0035] The electric toothbrush according to the present embodiment has a high-speed vibration of the brush tip, is easy for a finger to catch on the handle portion, is less likely to slip or shift, so there is little fatigue in the hand and fingers, and can be held with a small force. Since it can be held with a small force, it is possible to suppress applying an excessive pressing force of the brush to the teeth and gums. Furthermore, it is a housing shape that enables mounting of a torque-improving motor without increasing the external dimensions.

[0036] FIG. 6 is an external perspective view of the electric toothbrush according to the present invention, and has a detachable cover cap 1 mainly for preventing attachment of dust, dirt, and the like to the replacement brush portion.

[0037] FIG. 7 is an external perspective view with the cover cap 1 removed. An exchangeable brush 2 is provided at the upper part, and a housing 4 provided with a power switch 3 for starting and stopping a motor (not shown in FIG. 7) which is a vibration generation source, and the housing 4 has a detachable battery cover 5.

[0038] FIG. 8 is an external perspective view of the electric toothbrush of the present embodiment placed horizontally on a stand 6. Here, the view seen from the direction of arrow 12 is FIG. 12. FIG. 12 shows that there is a gap between the placement surface of the stand 6 and the brush 2. FIG. 11 is a diagram showing the relationship between the dimensions of the exchangeable brush 2 and the handle dimensions of the housing 4 of the present embodiment. The brush width of the exchangeable brush 2 is smaller than the minor axis of the handle of the housing 4, and the brush height of the exchangeable brush 2 is smaller than the major axis of the handle of the housing 4, and the centers of the exchangeable brush and the handle of the housing are set to substantially coincide. Therefore, a gap is formed between the placement surface and the brush as shown in FIG. 7. The same gap can be formed even when the surface opposite to FIG. 8 is placed in contact with the stand 6.

[0039] In this way, when placed horizontally, the brush does not contact the placement surface, so dust and dirt on the placement surface do not adhere to the brush.

[0040] FIG. 9 is an external perspective view of the electric toothbrush of the present embodiment placed vertically on the stand 6. What is a concern when placed vertically is tipping over.

[0041] Here, FIG. 10 is a view seen from the brush 2 side with the cover cap 1 removed, showing that the housing handle portion is substantially elliptical in the major diameter and minor diameter of the housing 4. In the present embodiment, the minor diameter:major diameter = 1:1.6.

[0042] In order to easily allow the user to determine that it is substantially elliptical, it is desirable that the minor diameter:major diameter = about 1:1.5. Further, as in the present embodiment, it is desirable that the brush direction coincides with the major diameter direction of the substantially elliptical shape.

[0043] When tipping over from the vertical state in FIG. 9 due to some external force, since the cross-section of the housing is substantially elliptical, it tips over substantially in the direction of arrow 8 or arrow 9, that is, in a direction perpendicular to the major diameter. Since the brush tip does not collide with the placement surface head-on, there is no damage to the brush. On the other hand, when tipping over in a vertical state with a substantially elliptical shape and a substantially regular polygon when viewing the housing 4 from the brush 2 side in the same way, the following occurs. That is, in the case of a substantially circular shape, the tipping direction is in the 360° direction, and in the case of a substantially regular polygon, it is in the direction perpendicular to each side but tips over in the 360° direction. In both cases, the tipping direction is not constant, and there is a possibility of tipping over from the brush tip side, and there is an advantage in the substantially elliptical shape.

[0044] From the above, it can be said that the substantially elliptical shape corresponds to both horizontal and vertical placements.

[0045] For the substantially elliptical handle portion, two vertexes in the major diameter direction are good for fingers or a handhold. That is, it can be said that slipping or displacement of the handle due to high-speed vibration is less likely to occur, and it is difficult to drop the electric toothbrush. Further, even when holding it in a penholder style, it can be held with a small force, which also contributes to preventing an excessive pressing force of the brush against the teeth or gums.

[0046] Furthermore, when changing the holding during toothbrushing, the direction can be easily determined only by the touch of the handle without visually checking the direction of the brush tip.

[0047] As described above, the electric toothbrush according to the present embodiment is an electric toothbrush that can reduce fatigue during toothbrushing and has a stable placement before and after toothbrushing. The cross-section of the handle portion may be a gradually changing substantially elliptical shape instead of a uniform substantially elliptical shape.

[0048] Next, an explanation for enabling the mounting of a torque improvement motor will be given. FIG. 13 shows a motor 30 with a circular cross-section and a motor 31 with a square cross-section. Here, the widths w1, w2, and w3 are of the same length, and further, the length dimensions in the output shaft direction of the motors are also the same, that is, motors with the same outer dimensions are shown.

[0049] In the present embodiment, the motor 31 is directly attached to the housing 4. FIG. 13 is an exploded perspective view showing that a motor 30 with a circular cross-section is attached to the housing 4 with screws 25a and 25b. FIG. 14 is an exploded perspective view showing that a motor 31 with a square cross-section can be attached to the housing 4 with screws 25a and 25b. Here, as described above, since the motor 30 with a circular cross-section and the motor 31 with a square cross-section have the same outer dimensions, the attachment positions of the screws 25a and 25b to the housing 4 are the same for the motor 30 and the motor 31.

[0050] The motors 30 and 31 are configured as small DC motors with brushes and include a rotor having a fixed magnet and a winding coil. The N pole and S pole opposite to the rotor of the magnet are referred to as poles, and the winding coil of the rotor is often referred to as a slot, and the configuration is often represented by the number of poles and the number of slots. For example, it is called 2 poles and 5 slots. The motor 30 with a circular cross-section has a large number of 2 poles and 3 slots. The motor 31 with a square cross-section enables 4 poles and 6 slots, and it is known that the torque is improved compared to 2 poles and 3 slots.

[0051] FIG. 15 is a view of motor 30 having a circular cross-section as seen from the direction of arrow L1 shown in FIG. 13, and FIG. 17 is a view of motor 31 having a square cross-section as seen from the direction of arrow L2 shown in FIG. 14. In both cases, the vicinity of screws 25a and 25b is the space necessary for inserting a tool such as a driver. On the other hand, the ineffective space ranges s1, s2, s3, s4 shown in FIG. 16 (spaces having a length in the depth direction of the paper) are the spaces necessary for mounting the motor (outer dimensions of the motor), but they indicate the ineffective space ranges that become ineffective spaces after the motor is assembled.

[0052] The ineffective space ranges s1, s2, s3, s4 can be used as effective spaces for mounting motor 31 having a square cross-section, which is the torque improvement motor according to the present embodiment.

[0053] Since the ineffective space is used as an effective space for motor 31, the torque improvement motor can be mounted without expanding the housing 4. That is, since the cross-section of the housing 4 is substantially elliptical, while arranging motor 31 having a square cross-section at the center, it is possible to arrange the fixing portions for fixing screws 25a and 25b to the housing 4 (battery case 11) in the major axis direction of the ellipse of the cross-section of the housing 4, and making the cross-section of the housing 4 elliptical has contributed to the improvement of the motor torque.

Explanation of Reference Numerals

[0054] 2 Brush 4 Housing 5 Torque Unit 7 Motor Unit 19 Worm Gear 20 Eccentric Weight 23 Motor Mounting Base 23a Fixed Arm 23b Fixed Arm 24 Motor 25a Motor Mounting Screw 25b Motor Mounting Screw 26 Stroke Shaft 28 Stroke Guide 29 Stroke Holder 30 Swing Lever 30a sliding hole 30b sliding hole 31 two-stage gear 32 single-stage gear 33 connecting pin 34 stroke pin 35a (swing lever) rotation axis 35b (two-stage gear) rotation axis

Claims

1. A housing, a motor having an eccentric weight and attached to the housing via a motor holding member, a transmission mechanism for transmitting the driving force of the motor, and a conversion mechanism for converting the rotational motion of the driving force into a linear reciprocating motion, characterized in that the conversion mechanism is fixed to the housing at a position different from the motor holding member. An electric toothbrush.

2. The electric toothbrush according to claim 1, wherein the transmission mechanism and the conversion mechanism are attached to a conversion mechanism holding portion fixed to the housing at a position different from the motor holding member.

3. The motor holding member has a mounting portion attached to the housing, The electric toothbrush according to claim 1 or 2, characterized in that it has an arm portion extending to the mounting portion in a direction parallel to the output shaft of the motor.

4. The electric toothbrush according to claim 3, wherein the mounting portion is provided at a position the same as or protruding toward the tip side of the output shaft from the mounting surface for attaching the motor to the motor holding member with respect to the direction in which the output shaft of the motor extends.

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