ELECTRIC VACUUM CLEANER

Abstract

Provided are rotary brush unit which is disposed inside suction port portion and in which two rotary shaft bodies each having brush are disposed in series and driving motor which separately rotates each of the rotary shaft bodies. With such a configuration, since it is possible to change a self-propelling direction of the suction port portion to the left and right direction in addition to the forward direction, it is possible to remarkably reduce the effort involved in an operation of changing the direction of the suction port portion.

Description

RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. JP2008-282714 filed on Nov. 4, 2008, the entire content of which is hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to an electric vacuum cleaner having a suction port portion and a handle portion.

BACKGROUND ART

In an existing electric vacuum cleaner, dust collecting performance using a sweeping-up rotary brush is good in regards to a floor surface and particularly a carpet surface. However, since the electric vacuum cleaner is equipped with a motor for driving the rotary brush, it is disadvantageous in that the suction port portion easily becomes heavy and the cleaning operation is wearisome. In order to solve the disadvantage, for example, Japanese Patent Unexamined Publication No. 2-7923 discloses a technology in which a suction port portion is provided with a self-propelling roller or a rotary brush itself is actively brought into contact with a floor surface so as to have a self-propelling property.

However, in the above-described technology, it is possible to reduce the effort upon operating the suction port portion forward or backward, but it is necessary to change a direction of the suction port portion by twisting a wrist upon changing the direction in the left and right direction. For this reason, it is not possible to reduce the effort involved. Particularly, in an upright cleaner having a heavy suction port portion, it takes a good deal of effort to change the direction of the suction port portion. Since the direction of the suction port portion is frequently changed during an actual cleaning operation, particularly at this time, a large burden is applied to the wrist. As a result, the wrist feels fatigued after a long-time cleaning operation.

SUMMARY OF THE INVENTION

An object of the invention is to provide an electric vacuum cleaner capable of changing a direction of a suction port portion to a desired changing direction and reducing the burden applied to a user's wrist.

According to an aspect of the invention, there is provided an electric vacuum cleaner including: a cleaner body portion which has an electric blower for generating a suction wind; a suction port portion which sucks dust together with the suction wind; a handle portion which moves the suction port portion; a rotary brush unit which is disposed inside the suction port portion and in which two rotary shaft bodies each having a brush are disposed in series; a rotary brush unit driving portion which separately rotates each of the rotary shaft bodies; and a rotation speed difference generating mechanism which generates a difference in the rotation speed between two rotary shaft bodies.

According to the invention, the rotary brush unit includes two rotary shaft bodies, and the rotation speed difference generating mechanism generates a difference in the rotation speed between two rotary shaft bodies. For this reason, it is possible to easily change the direction of the suction port portion to the desired changing direction. Accordingly, since it is possible to remarkably reduce a burden during a cleaning operation, it is possible to more comfortably perform the cleaning operation which is a comparatively heavy labor in the housework.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an entire perspective view showing a cleaner body portion of an electric vacuum cleaner according to a first embodiment of the invention.

FIG. 2 is a partially sectional view showing a suction port portion according to the embodiment.

FIG. 3 is a block diagram showing a configuration of an electric controller according to the embodiment.

FIG. 4 is an entire perspective view showing the cleaner body portion of the electric vacuum cleaner according to a second embodiment of the invention.

FIG. 5 is a plan view showing a rotary brush unit of the electric vacuum cleaner according to a third embodiment of the invention.

FIG. 6 is a plan view showing the rotary brush unit of the electric vacuum cleaner according to a fourth embodiment of the invention.

FIG. 7 is a plan view showing the rotary brush unit of the electric vacuum cleaner according to a fifth embodiment of the invention.

FIG. 8 is a plan view showing the rotary brush unit of the electric vacuum cleaner according to a sixth embodiment of the invention.

FIG. 9 is a plan view showing the rotary brush unit of the electric vacuum cleaner according to a seventh embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, exemplary embodiments of the invention will be described with reference to the accompanying drawings. In addition, the invention is not limited to the embodiments.

First Embodiment

FIG. 1 is an entire perspective view showing a cleaner body portion of an electric vacuum cleaner according to a first embodiment of the invention. FIG. 2 is a partially sectional view showing a suction port portion according to the embodiment when seen from the bottom of the suction port portion.

As shown in FIG. 1, an electric vacuum cleaner according to this embodiment includes suction port portion 1 which sucks dust, handle portion 11 which moves suction port portion 1, and cleaner body portion 12 of which a lower portion is provided with suction port portion 1 and an upper portion is provided with handle portion 11. Cleaner body portion 12 includes an electric blower for generating a suction wind. Suction port portion 1 sucks dust together with the suction wind generated by the electric blower. Switch lever portion 10 is attached onto handle portion 11. Switch lever portion 10 is attached to a position where switch lever portion 10 is operable by a finger when gripping handle portion 11 using a hand. When switch lever portion 10 is pushed down in the left and right direction, as depicted by the arrow, suction port portion 1 is controlled so that the direction thereof is changed to the direction in which switch lever portion 10 is pushed down.

As shown in FIG. 2, rotary brush unit 2 is disposed inside suction port portion 1. Rotary brush unit 2 includes two rotary shaft bodies 2A and 2B. Brush 3 is disposed in surfaces of rotary shaft bodies 2A and 2B.

In FIG. 2, brush 3 is formed as a so-called bristle transplant brush in which bristles are tied and transplanted inside a hole, but may be formed as a brush in which a narrow raised fabric is inserted and fixed into an undercut groove or a bonded brush.

Each of the rotary shaft bodies 2A and 2B is provided with driving motor 4 and decelerating gear 5. Driving motor 4 is connected to decelerating gear 5 to thereby form a rotary brush unit driving portion. An output shaft of decelerating gear 5 is fixed to each of rotary shaft bodies 2A and 2B. With such a configuration, when driving motors 4 are driven, rotary shaft bodies 2A and 2B located in the peripheries thereof rotate.

Likewise, a rotary mechanism is constituted by only rotary brush unit 2 in such a manner that driving motor 4 and decelerating gear 5 are disposed inside each of rotary shaft bodies 2A and 2B. Accordingly, it is not necessary to dispose a large component such as a driving motor in the inside of suction port portion 1. For this reason, it is possible to decrease the size of suction port portion 1. That is, it is possible to realize suction port portion 1 which can move and turn slightly and has good operability or cleaner body portion 12 which is small in size and low in weight.

The length of brush 3 is set to a length at which brush 3 slightly comes into contact with a floor surface. For this reason, when rotary shaft bodies 2A and 2B rotate in a direction (positive direction) in which suction port portion 1 is pushed forward, suction port portion 1 propels itself, thereby improving the operability of cleaner body portion 12. That is, when driving motors 4 inside rotary shaft bodies 2A and 2B rotate at the same speed (including substantially the same speed) in the same direction (positive direction), suction port portion 1 propels itself forward.

In addition, each of rotary shaft bodies 2A and 2B is driven by a separate driving motor 4. For this reason, it is possible to independently change the rotation speeds thereof. When the right driving motor on the user side rotates faster than the left driving motor or only the right driving motor rotates, a direction of suction port portion 1 is changed to the left direction. On the other hand, when the left driving motor rotates faster than the right driving motor or only the left driving motor rotates, the direction of suction port portion 1 is changed to the right direction.

In addition, when the driving motor located in the desired rotation direction rotates in the reverse direction and the opposite driving motor rotates in the positive direction, it is possible to further strongly change the direction of suction port portion 1.

Switch lever portion 10 controls driving motors 4 inside rotary shaft bodies 2A and 2B through the electric controller shown in FIG. 3. FIG. 3 is a block diagram showing a circuit of the electric vacuum cleaner according to this embodiment. In FIG. 3, motor 35 for driving the electric blower generating the suction wind is connected in parallel to AC power source 36. Power switch portion 37 controlling an on-off state of motor 35 is disposed close to handle portion 11 of cleaner body portion 12 (not shown in FIG. 1). Driving motor 38A (one driving motor 4 shown in FIG. 2) for driving rotary shaft body 2A is connected in series to rotary shaft body switch portion 39A for controlling the on-off state of driving motor 38A. In the same manner, driving motor 38B (the other driving motor 4 shown in FIG. 2) for driving rotary shaft body 2B is connected in series to rotary shaft body switch portion 39B for controlling an on-off state of driving motor 38B. The two serial connection portions are connected in parallel to motor 35. Rotary shaft body switch portions 39A and 39B are operated in an interlocking manner as depicted by the dotted line by switch lever portion 10.

In the normal state where no operation is performed, switch lever portion 10 turns on rotary shaft body switch portions 39A and 39B, and rotates driving motors 38A and 38B at the same speed in the same direction (positive direction). Accordingly, suction port portion 1 propels itself forward. When switch lever portion 10 is pushed down in the left and right direction, as described above, switch lever portion 10 controls driving motors 38A and 38B inside rotary shaft bodies 2A and 2B so that the direction of suction port portion 1 is changed to the direction in which switch lever portion 10 is pushed down.

That is, when switch lever portion 10 is pushed down in the right direction, only left driving motor 38B on the user side rotates in the positive direction. For this reason, it is possible to easily change the direction of suction port portion 1 to the right direction. At this time, when switch portion 39A of rotary shaft body 2A and switch portion 39B of rotary shaft body 2B are interlocked with each other so that right driving motor 38A on the user side rotates in a direction opposite to the rotation direction of driving motor 38B, it is possible to more easily change the direction of suction port portion 1 to the right direction. In the same manner, when switch portion 39A of rotary shaft body 2A and switch portion 39B of rotary shaft body 2B are interlocked with each other so that right driving motor 38A on the user side rotates slower than driving motor 38B, it is possible to more easily change the direction of suction port portion to the right direction. In any case, there is a difference in the rotation speed between rotary shaft bodies 2A and 2B.

On the contrary, in order to further change the direction of suction port portion 1 to the left direction, switch portion 39A of rotary shaft body 2A and switch portion 39B of rotary shaft body 2B are interlocked with each other as below. Switch portion 39A of rotary shaft body 2A and switch portion 39B of rotary shaft body 2B are interlocked with each other so that only right driving motor 38A on the user side rotates in the positive direction, left driving motor 38B on the user side rotates in a direction opposite to the rotation direction of driving motor 38A, or left driving motor 38B on the user side rotates more slowly than driving motor 38A when switch lever portion 10 is pushed down in the left direction.

That is, in this embodiment, rotation speed difference generating mechanisms are separately disposed in each of rotary shaft bodies 2A and 2B, and include separately rotating driving motors 38A and 38B, rotary shaft body switch portions 39A and 39B, and switch lever portion 10.

As described above, in this embodiment, the direction of suction port portion 1 can be changed by generating a difference in the rotation speed between two rotary shaft bodies 2A and 2B. For this reason, it is possible to reduce a burden applied to an arm or wrist upon changing the direction of suction port portion 1 in the left and right direction.

In this embodiment, suction port portion 1 propels itself in accordance with the rotation of rotary shaft bodies 2A and 2B. For this reason, since suction port portion 1 propels itself forward or backward during a cleaning operation, it is possible to reduce the burden during the cleaning operation.

In this embodiment, suction port portion 1 propels itself in accordance with the rotation of rotary shaft bodies 2A and 2B. For this reason, since there is a difference in the rotation speed between two rotary shaft bodies 2A and 2B, it is possible to reduce the burden applied to the arm or wrist upon changing the direction of suction port portion 1.

In this embodiment, driving motor 4 is disposed inside each of rotary shaft bodies 2A and 2B. For this reason, it is possible to decrease the size of suction port portion 1 and to easily handle suction port portion 1 in a narrow space. In addition, it is possible to dispose rotary brush unit 2 in substantially the entire width of suction port portion 1, and to improve a cleaning performance for cleaning a side wall.

In this embodiment, handle portion 11 includes switch lever portion 10 which is operable in the left and right direction, and the rotation of two rotary shaft bodies 2A and 2B of rotary brush unit 2 is controlled so that the direction of suction port portion 1 is changed to the direction in which switch lever portion 10 is operated. For this reason, it is possible to change the direction of suction port portion 1 just by using a finger tip without performing a large action in which handle portion 11 is twisted or pushed down.

Second Embodiment

FIG. 4 is an entire perspective view showing the electric vacuum cleaner according to a second embodiment of the invention. This embodiment is different from the first embodiment in that switch lever portion 10 is not provided. Instead of switch lever portion 10, handle portion 11 which is twistable in the left and right direction is provided. The rotation speed of two rotary shaft bodies 2A and 2B disposed in rotary brush unit 2 inside suction port portion 1 is controlled through the electric controller (not shown) so that the direction of suction port portion 1 is changed to the twisting direction of handle portion 11. When the twisting amount becomes large, the difference in the rotation speed between rotary shaft bodies 2A and 2B becomes large, and the turning amount becomes large. In the case where handle portion 11 is not twisted, suction port portion rotates forward. Since the other configurations are same as those of the first embodiment, detailed description thereof will be omitted.

As described above, in this embodiment, handle portion 11 is twistable in the left and right direction. When handle portion 11 is twisted in the left and right direction, the rotation of two rotary shaft bodies 2A and 2B of rotary brush unit 2 is controlled so that the direction of suction port portion 1 is changed to the twisting direction of handle portion 11. Accordingly, it is possible to change the self-propelling direction of the suction port portion while having the same feeling of operation as with a general cleaner having an oscillation mechanism.

Third Embodiment

FIG. 5 is a plan view showing rotary brush unit 2 inside suction port portion 1 of the electric vacuum cleaner according to a third embodiment of the invention. Rotary shaft bodies 2A and 2B constituting rotary brush unit 2 are rotatably connected to each other through connection portion 30. Connection portion 30 is formed as a simple bearing, and a difference in the rotation speed between rotary shaft bodies 2A and 2B is absorbed by connection portion 30. Brush 3 is attached to surfaces of rotary shaft bodies 2A and 2B.

Stiff brushes 3A depicted by the solid line are attached to predetermined ranges 101 of rotary brush unit 2. Soft brush 3B depicted by the dotted line is attached to predetermined ranges 102 at the center of rotary brush unit 2. Since the other configurations are the same as those of the first embodiment, detailed description thereof will be omitted.

With such a configuration, since a large self-propelling force is generated at a position far from the turning center, it is possible to more efficiently turn suction port portion 1.

In this embodiment, the direction of the suction port portion is changed by generating a difference in the rotation speed between the driving motors using switch lever portion 10 of the first embodiment or handle portion 11B, which is twistable, of the second embodiment. At this time, in this embodiment, since the brush 3 includes stiff brushes 3A in the vicinity of both ends of rotary brush unit 2 and soft brushes 3B in the vicinity of the center thereof, it is possible to more efficiently turn suction port portion 1.

As described above, in this embodiment, the stiffness of each of the brushes 3 in the vicinity of both ends of rotary brush unit 2 is set to be larger than that in the vicinity of the center thereof. Accordingly, since it is possible to improve the direction changing force of suction port portion 1, it is possible to change the self-propelling direction even on a floor surface having a high resistance such as a deep carpet.

Fourth Embodiment

FIG. 6 is a plan view showing rotary brush unit 2 inside suction port portion 1 of the electric vacuum cleaner according to a fourth embodiment of the invention. In rotary shaft bodies 2A and 2B constituting rotary brush unit 2, the outer diameter of range 110 in the vicinity of the center of rotary brush unit 2 is small, and the outer diameter becomes large toward both ends. The length of brush 3 attached to rotary shaft bodies 2A and 2B becomes shorter as the outer diameters of rotary shaft bodies 2A and 2B become larger. That is, in each of rotary shaft bodies 2A and 2B, brush 3 includes brushes 3C and 3D of which the lengths becomes short in a direction from the center to both ends. Accordingly, as depicted by one-dot dashed line P1, the outer diameter of brush 3 up to the end of the bristle is substantially uniform throughout the entire width of the rotary brush unit 2. Since the other configurations are same as those of the first embodiment, detailed description thereof will be omitted.

With such a configuration, since the brush is hardly pushed down due to the short length of the brush, it is possible to improve the self-propelling force at both ends of rotary brush unit 2 even in the case of using a brush formed of the same material. That is, it is possible to more efficiently turn suction port portion 1.

In this embodiment, the direction of the suction port portion is changed by generating a difference in the rotation speed between the driving motors using switch lever portion 10 of the first embodiment or handle portion 11B, which is twistable, of the second embodiment. At this time, in this embodiment, since brush 3 includes brushes 3C and 3D of which the lengths become short in a direction from the center of rotary brush unit 2 to both ends thereof, it is possible to more efficiently turn suction port portion 1.

As described above, in this embodiment, the outer diameter of each of rotary shaft bodies 2A and 2B in the vicinity of both ends of rotary brush unit 2 is set to be larger than that in the vicinity of the center thereof. In addition, the length of each of brushes 3 in the vicinity of both ends of rotary brush unit 2 is set to be shorter than that in the vicinity of the center thereof, and the outer diameter of each of brushes 3 up to the end of the bristle in the vicinity of both ends of rotary brush unit 2 is set to be same as that in the vicinity of the center thereof. Accordingly, it is possible to improve the direction changing force of suction port portion 1, and to change the self-propelling direction even on a floor surface having a large sliding resistance such as a deep carpet. Further, since the outer diameter of each of brushes 3 up to the end of the bristle is set to be uniform, it is possible to have uniform contact with a floor surface. Accordingly, it is possible to obtain a uniform suction function and a uniform self-propelling function throughout the entire width of rotary brush unit 2.

Fifth Embodiment

FIG. 7 is a plan view showing rotary brush unit 2 inside suction port portion 1 of the electric vacuum cleaner according to a fifth embodiment of the invention. In brush 3 attached to the surfaces of rotary shaft bodies 2A and 2B constituting rotary brush unit 2, the length of brush 3 is short in range 110 in the vicinity of the center of rotary brush unit 2, and becomes longer toward both ends. The outer diameter of brush 3 up to the end of the bristle is depicted by one-dot chain line P2. That is, brush 3 includes brushes 3E and 3F which are respectively disposed in rotary shaft bodies 2A and 2B so that the lengths thereof become longer in a direction from the center of rotary brush unit 2 to both ends thereof. Since the other configurations are same as those of the first embodiment, detailed description thereof will be omitted.

With such a configuration, brush 3 at both ends of rotary brush unit 2 strongly comes into contact with the floor surface to thereby generate a large self-propelling force. As a result, it is possible to more efficiently turn suction port portion 1.

In this embodiment, the direction of the suction port portion can be changed by generating a difference in the rotation speed between the driving motors using switch lever portion 10 of the first embodiment or handle portion 11B, which is twistable, of the second embodiment. At this time, in this embodiment, since brush 3 includes brushes 3E and 3F of which the lengths become longer in a direction from the center of rotary brush unit 2 to both ends thereof, it is possible to more efficiently turn suction port portion 1.

As described above, in this embodiment, the length of each of brushes 3 in the vicinity of both ends of rotary brush unit 2 is set to be longer than that in the vicinity of the center thereof. Accordingly, since it is possible to improve the direction changing force of suction port portion 1, it is possible to change the self-propelling direction even on a floor surface having a large resistance such as a deep carpet. Further, since the distance from the center of the attachment portion of brush 3 is uniform, it is possible to easily perform a transplanting operation using an automatic machine.

Sixth Embodiment

FIG. 8 is a plan view showing rotary brush unit 2 inside suction port portion 1 of the electric vacuum cleaner according to a sixth embodiment of the invention. In the same manner as the above-described embodiments, brush 3 is attached to the surfaces of rotary shaft bodies 2A and 2B constituting rotary brush unit 2. The pitch between brushes 3 attached to predetermined ranges 120 of both ends of rotary brush unit 2 is narrow. The pitch at predetermined range 121 in the vicinity of the center of rotary brush unit 2 is wide. That is, brush 3 includes high-density brush 3G attached to both ends of rotary brush unit 2 and low-density brush 3H attached to the vicinity of the center thereof. Since the other configurations are same as those of the first embodiment, detailed description thereof will be omitted.

Accordingly, it is possible to generate a large self-propelling force at both ends of rotary brush unit 2. For this reason, it is possible to more efficiently turn suction port portion 1.

In this embodiment, the direction of the suction port portion is changed by generating a difference in the rotation speed between the driving motors using switch lever portion 10 of the first embodiment or handle portion 11B, which is twistable, of the second embodiment. At this time, in this embodiment, since brush 3 includes high-density brush 3G attached to both ends of rotary brush unit 2 and low-density brush 3H attached to the vicinity of the center thereof, it is possible to more efficiently turn suction port portion 1.

As described above, in this embodiment, the density of each of brushes 3 in the vicinity of both ends of rotary brush unit 2 is set to be higher than that in the vicinity of the center thereof. Particularly, brush 3 of each of rotary shaft bodies 2A and 2B is formed with a comb tooth shape, and the pitch of the comb tooth shape of each of brushes 3 in the vicinity of both ends of rotary brush unit 2 is set to be denser than that of each of brushes 3 in the vicinity of the center thereof. Accordingly, since it is possible to improve the direction changing force of suction port portion 1, it is possible to change the self-propelling direction even on a floor surface having a high resistance such as a deep carpet. In addition, since it is possible to make the type, stiffness, and length of the bristles of brush 3 uniform throughout the entire width of brush unit 2, it is possible to improve the productivity.

Seventh Embodiment

FIG. 9 is a plan view showing rotary brush unit 2 inside suction port portion 1 of the electric vacuum cleaner according to a seventh embodiment of the invention. In the same manner as the above-described embodiments, brush 3 is attached to the surfaces of rotary shaft bodies 2A and 2B constituting rotary brush unit 2. In brushes 3, four lines of brushes 3I are respectively attached to predetermined ranges 130 of both ends of rotary brush unit 2. Two lines of brushes 3J are attached to range 131 in the vicinity of the center of rotary brush unit 2. Since the other configurations are same as those of the first embodiment, detailed description thereof will be omitted.

Accordingly, it is possible to generate a large self-propelling force at both ends of rotary brush unit 2. For this reason, it is possible to more efficiently turn suction port portion 1.

In this embodiment, the direction of the suction port portion is changed by generating a difference in the rotation speed between the driving motors using switch lever portion 10 of the first embodiment or handle portion 11B, which is twistable, of the second embodiment. At this time, in this embodiment, since brush 3 includes four lines of brushes 3I in both ends of rotary brush unit 2 and two lines of brushes 3J in the vicinity of the center thereof, it is possible to more efficiently turn suction port portion 1.

As described above, brushes 3 of rotary shaft bodies 2A and 2B are formed in a stripe shape, and the number of lines of brushes 3 in the vicinity of both ends of rotary brush unit 2 is larger than that of brushes 3 in the vicinity of the center thereof. Accordingly, since it is possible to improve the direction changing force of suction port portion 1, it is possible to change the self-propelling direction even on a floor surface having a high resistance such as a deep carpet. In addition, since it is possible to make the type, stiffness, length, and transplanting pitch of the bristles of brush 3 uniform throughout the entire width of brush unit 2, it is possible to improve the productivity.

As described above, the electric vacuum cleaner according to the invention includes the cleaner body portion which has the electric blower for generating a suction wind; the suction port portion which sucks dust together with the suction wind; the handle portion which moves the suction port portion; the rotary brush unit which is disposed inside the suction port portion and in which two rotary shaft bodies each having a brush are disposed in series; the rotary brush unit driving portion which separately rotates each of the rotary shaft bodies; and the rotation speed difference generating mechanism which generates a difference in the rotation speed between two rotary shaft bodies.

With such a configuration, it is possible to reduce the burden applied to the arm or wrist upon changing the direction of suction port portion in the left and right direction.

In the invention, the suction port portion propels itself in accordance with the rotation of the rotary shaft bodies. With such a configuration, since the suction port portion propels itself forward or backward during the cleaning operation, it is possible to reduce the burden applied to the arm or wrist.

In the invention, the rotary brush unit driving portion is configured as the driving motor disposed inside each of the rotary shaft bodies. With such a configuration, it is possible to decrease the size of the suction port portion and to easily handle the suction port portion in a narrow space. In addition, it is possible to dispose the rotary brush unit in substantially the entire width of the suction port portion, and to improve the cleaning performance for cleaning a side wall.

In the invention, the handle portion includes the switch lever portion which is operable in the left and right direction, and controls the rotation of two rotary shaft bodies of the rotary brush unit so that the direction of the suction port portion is changed to the operation direction of the switch lever portion. With such a configuration, it is possible to change the direction of the suction port portion just by using a finger tip without performing a large action in which the handle portion is twisted or pushed down.

In the invention, the handle portion is twistable in the left and right direction. When the handle portion is twisted in the left and right direction, the rotation of two rotary shaft bodies of the rotary brush unit is controlled so that the direction of the suction port portion is changed to the twisting direction of the handle portion. With such a configuration, it is possible to change the self-propelling direction of the suction port portion while having the same feeling of operation as with a general cleaner having an oscillation mechanism.

In the invention, the stiffness of each of the brushes in the vicinity of both ends of the rotary brush unit is set to be larger than that in the vicinity of the center thereof. With such a configuration, since it is possible to improve the direction changing force of the suction port portion, it is possible to change the self-propelling direction even on a floor surface having a high resistance such as a deep carpet.

In the invention, the outer diameter of each of the rotary shaft bodies in the vicinity of both ends of the rotary brush unit is set to be larger than that in the vicinity of the center thereof. In addition, the length of each of the brushes in the vicinity of both ends of the rotary brush unit is set to be shorter than that in the vicinity of the center thereof, and the outer diameter of each of the brushes up to the end of the bristle in the vicinity of both ends of the rotary brush unit is set to be same as that in the vicinity of the center thereof

With such a configuration, it is possible to improve the direction changing force of the suction port portion, and to change the self-propelling direction even on a floor surface having a large sliding resistance such as a deep carpet. Further, since the outer diameter of the brush up to the end of the bristle is set to be uniform, it is possible to have uniform contact with a floor surface. Accordingly, it is possible to obtain a uniform suction function and a uniform self-propelling function throughout the entire width of the rotary brush unit.

In the invention, the length of each of the brushes in the vicinity of both ends of the rotary brush unit is set to be longer than that in the vicinity of the center thereof With such a configuration, since it is possible to improve the direction changing force of the suction port portion, it is possible to change the self-propelling direction even on a floor surface having a large resistance such as a deep carpet. Further, since the distance from the center of the attachment portion of the brush is uniform, it is possible to easily perform a transplanting operation using an automatic machine.

In the invention, the density of each of the brushes in the vicinity of both ends of the rotary brush unit is set to be higher than that in the vicinity of the center thereof With such a configuration, since it is possible to improve the direction changing force of the suction port portion, it is possible to change the self-propelling direction even on a floor surface having a high resistance such as a deep carpet. In addition, since it is possible to make the type, stiffness, and length of the bristles of the brush uniform throughout the entire width of the brush unit, it is possible to improve the productivity.

In the invention, the brushes of each of the rotary shaft bodies are formed with a comb tooth shape, and the pitch of the comb tooth shape of each of the brushes in the vicinity of both ends of the rotary brush unit is set to be denser than that in the vicinity of the center thereof.

With such a configuration, since it is possible to improve the direction changing force of the suction port portion, it is possible to change the self-propelling direction even on a floor surface having a high resistance such as a deep carpet. In addition, since it is possible to make the type, stiffness, and length of the bristles of the brush uniform throughout the entire width of the brush unit, it is possible to improve the productivity.

In the invention, the brush of the rotary shaft body is formed in a stripe shape, and the number of lines of the brushes in the vicinity of both ends of the rotary brush unit is set to be larger than that in the vicinity of the center thereof.

With such a configuration, since it is possible to improve the direction changing force of the suction port portion, it is possible to change the self-propelling direction even on a floor surface having a high resistance such as a deep carpet. In addition, since it is possible to make the type, stiffness, and length of the bristles of the brush uniform throughout the entire width of the brush unit, it is possible to improve the productivity.

As described above, the advantage of the invention is particularly apparent in a heavy electric vacuum cleaner such as an upright cleaner. For this reason, it is possible for even an old person, a woman, or a child to perform a cleaning operation using the electric vacuum cleaner, and to suppress fatigue even during a lengthy cleaning operation. In addition, regardless of age, sex or whether used at home or the office, it is possible to reduce the effort involved during a cleaning operation.

Claims

1. An electric vacuum cleaner comprising:

a cleaner body portion which has an electric blower for generating a suction wind;

a suction port portion which sucks dust together with the suction wind;

a handle portion which moves the suction port portion;

a rotary brush unit which is disposed inside the suction port portion and in which two rotary shaft bodies each having a brush are disposed in series;

a rotary brush unit driving portion which separately rotates each of the rotary shaft bodies; and

a rotation speed difference generating mechanism which generates a difference in the rotation speed between the two rotary shaft bodies.

2. The electric vacuum cleaner of claim 1,

wherein the suction port portion propels itself in accordance with the rotation of the rotary shaft bodies.

3. The electric vacuum cleaner of claim 1,

wherein the rotary brush unit driving portion is configured as a driving motor which is disposed inside each of the rotary shaft bodies.

4. The electric vacuum cleaner of claim 1,

wherein the handle portion includes a switch lever portion which is operable in the left and right direction, and controls the rotation of the two rotary shaft bodies of the rotary brush unit so that a direction of the suction port portion is changed to the operation direction of the switch lever portion.

5. The electric vacuum cleaner of claim 1,

wherein the handle portion is twistable in the left and right direction, and

wherein when the handle portion is twisted in the left and right direction, the rotation of the two rotary shaft bodies of the rotary brush unit is controlled so that a direction of the suction port portion is changed to the twisting direction of the handle portion.

6. The electric vacuum cleaner of claim 1,

wherein stiffness of each of the brushes in the vicinity of both ends of the rotary brush unit is set to be harder than that in the vicinity of the center thereof.

7. The electric vacuum cleaner of claim 1,

wherein an outer diameter of each of the rotary shaft bodies at both ends of the rotary brush unit is set to be larger than that in the vicinity of the center,

wherein a length of each of the brushes in the vicinity of both ends of the rotary brush unit is set to be shorter than that in the vicinity of the center thereof, and

wherein an outer diameter of each of the brushes up to the end of its bristles in the vicinity of both ends of the rotary brush unit is set to be same as that in the vicinity of the center thereof

8. The electric vacuum cleaner of claim 1,

wherein a length of each of the brushes in the vicinity of both ends of the rotary brush unit is set to be longer than that in the vicinity of the center thereof.

9. The electric vacuum cleaner of claim 1,

wherein a density of each of the brushes in the vicinity of both ends of the rotary brush unit is set to be higher than that in the vicinity of the center thereof.

10. The electric vacuum cleaner of claim 9,

wherein the brushes of the rotary shaft bodies are formed in a comb tooth shape, and a pitch of the comb tooth shape of each of the brushes in the vicinity of both ends of the rotary brush unit is set to be narrower than that in the vicinity of the center thereof.

11. The electric vacuum cleaner of claim 9,

wherein the brushes of the rotary shaft bodies are formed in a stripe shape, and the number of lines of the brushes in the vicinity of both ends of the rotary brush unit is set to be larger than that in the vicinity of the center thereof.