JP6051007B2 - Electric vacuum cleaner - Google Patents

Description

  The present invention relates to an electric blower, a dust collection unit, and a vacuum cleaner including a cord reel around which a power cord is wound.

In recent years, in order to improve usability, it has been desired to reduce the size and weight of the vacuum cleaner body.
In this regard, Patent Document 1 discloses a suction port disposed in a front portion of a vacuum cleaner body, and a cyclone disposed in a posture in which a central axis of a cylinder is horizontal in the left-right direction of the vacuum cleaner body behind the suction port. A dust collecting chamber of the type, and an electric blower and a power supply unit arranged in parallel in the direction of the central axis of the cylinder of the dust collecting chamber, and the air flow emitted from the electric blower is a short air flow in which a substrate is disposed. There is described a vacuum cleaner that exhausts through a passage and that is reduced in size by arranging an electric blower and a power supply unit in parallel in the central axis direction of the cylinder of the dust collection chamber.
Patent Document 1 describes a dust collection chamber disposed behind the cleaner body, and a blower and a power supply unit disposed in front thereof.

JP 2004-16607 A

However, in the conventional vacuum cleaner, the dust collecting chamber is disposed in the front, and the electric blower and the cord reel are disposed in the rear. Therefore, the mass of the cleaner body is concentrated in the rear. Therefore, when the cleaner body is pulled by the suction hose portion, the front wheels are likely to float and bounce, and the traveling direction is unstable, so that the traveling followability of the cleaner body is not good.
In addition, as described in Patent Document 1, when a dust collection chamber is arranged behind the cleaner body and a blower and a power supply unit are arranged in front of the dust collection chamber, a large weight blower and power supply unit Both of them will be arranged in front of the vacuum cleaner body, and when the vacuum cleaner body is pulled by the suction hose part, it becomes difficult for the front wheels to get over the step, and this also improves the running followability of the vacuum cleaner body There was no problem.

  The present invention has been made in consideration of the above-described circumstances, and provides a vacuum cleaner having improved traveling followability of a cleaner body.

  The present invention includes an electric blower disposed on the front side of the cleaner body and connected to the suction hose, a cord reel disposed on the rear side of the cleaner body and wound with a power cord, A dust collection unit that is disposed between the electric blower and the cord reel and collects dust sucked through the suction hose, a pair of main wheels that are arranged on the left and right sides of the dust collection unit, and a center of gravity of the electric blower There is provided a vacuum cleaner comprising a caster in contact with a floor surface behind a position and in front of the main wheel.

  In the electric vacuum cleaner according to the present invention, the dust collecting unit is arranged between the electric blower arranged on the front side of the vacuum cleaner body and the cord reel arranged on the rear side. And distributed backwards. Therefore, even if it is pulled by the suction hose part, the casters of the front wheels are hardly lifted and the running is stabilized.

1 is an external perspective view of a vacuum cleaner according to an embodiment of the present invention. It is a top view of the cleaner body concerning an embodiment of this invention. It is a side view of the cleaner body concerning an embodiment of this invention. It is a 1st disassembled perspective view of the cleaner body concerning an embodiment of this invention (the circumference of a bogie and a wheel). It is a 2nd disassembled perspective view of the vacuum cleaner main body which concerns on embodiment of this invention (electric blower periphery). It is a 3rd disassembled perspective view of the vacuum cleaner main body which concerns on embodiment of this invention (duct periphery). It is a 4th disassembled perspective view of the cleaner main body which concerns on embodiment of this invention (code reel periphery). It is AA arrow sectional drawing of FIG. It is AA arrow sectional drawing of the state in which the dust collection unit was removed. It is AA arrow sectional drawing of the state in which the dust collection unit was removed. 1 is an external perspective view of a dust collection unit according to an embodiment of the present invention. It is AA arrow sectional drawing shown in FIG. 2 of the dust collection unit which concerns on embodiment of this invention. It is explanatory drawing which shows the flow path of the airflow in the cleaner body shown in FIG. 1 is an external perspective view of a universal frame according to an embodiment of the present invention. It is the bottom view of the free frame which concerns on embodiment of this invention, the side view of the front-back direction, and sectional drawing. It is the bottom view of the universal frame which concerns on embodiment of this invention, and the side view and sectional drawing of the left-right direction.

  Hereinafter, the present invention will be described in more detail with reference to the drawings. In addition, the following description is an illustration in all the points, Comprising: It should not be interpreted as limiting this invention.

[Overall description of the vacuum cleaner]
FIG. 1 is an external perspective view of a vacuum cleaner according to an embodiment of the present invention, and FIGS. 2 and 3 are a plan view and a side view of a vacuum cleaner body of the vacuum cleaner shown in FIG.

  As shown in these drawings, the vacuum cleaner 1 includes a vacuum cleaner body 100 in which a cyclone type dust collection unit 500 is detachably incorporated, and a suction hose portion 300.

  The suction hose part 300 includes a suction hose 301, an extension pipe 302, a suction part 303 connected to the tip of the extension pipe 302, a hand handle 304, an operation part 305 attached to the hand handle 304, and a connection part 306. Is provided.

  The suction hose 301 is detachably connected to the front of the cleaner main body 100 via the connection portion 306, and the user holds the hand handle 304 by hand while bringing the suction portion 303 at the tip of the extension pipe 302 into contact with the floor surface. Can be moved.

Since the vacuum cleaner main body 100 is provided with a pair of ring-shaped wheels 140 on both sides and a free wheel 117 at the lower front, when the user moves while holding the hand handle 304 by hand, The operation can be followed.
Ring-shaped wheel 140 is a specific embodiment of the main wheel of the present invention.

  The vacuum cleaner main body 100 sucks dust on the floor together with air from the suction portion 303 to the dust collecting unit 500 via the extension pipe 302 and the suction hose 301. Ring-shaped wheel bodies 110 are arranged on the left and right sides of the dust collection unit 500.

  The user visually checks the dust collection status of the dust collection unit 500 inside the vacuum cleaner main body 100 from the central opening 141 of the ring-shaped wheel main body 110, and pulls out the dust collection unit 500 from the upper part of the vacuum cleaner main body 100 as appropriate. Dust collected in the unit 500 can be discarded.

  As shown in FIG. 2, a power cord insertion plug 131 of a cord reel (described later) and a brake button 132 for adjusting the length of the power cord are provided on the upper rear portion of the vacuum cleaner main body 100. .

  Further, since the cleaner body 100 includes the hand handle 115, the user can hold the hand handle 115 and lift and transport the cleaner body 100.

  4 to 7 are exploded perspective views of the cleaner body 100, FIG. 8 is a cross-sectional view taken along arrow AA in FIG. 2, and FIG. 9 corresponds to FIG. 8 in a state where the dust collection unit 500 is removed from the cleaner body 100. 10 and 10 are cross-sectional views taken along line BB in FIG. The configuration of the cleaner body 100 will be described with reference to these drawings.

  The vacuum cleaner main body 100 has an elongated cart 101 (see FIG. 4) constituting a lower portion thereof, and a lower first casing 102 (see FIG. 5) that is installed in front of the cart 101 and accommodates the electric blower 106 (see FIG. 5). See). Further, a second housing 103 (see FIG. 4) that constitutes a dust collection chamber 150 installed in the center of the carriage 101 to accommodate the dust collection unit 500, and a cord reel 108 installed in the rear of the carriage. A third housing 107 (see FIG. 7) is provided. An exhaust port 133 is formed in the third housing 107.

  The electric blower 106 (see FIG. 5 and FIG. 8) is installed in the lower first housing 102 via a pedestal 122 (see FIG. 5) so that the rotation axis direction, that is, the blowing direction is directed in the direction of gravity. . A lower first housing cover 104 and a duct 105 shown in FIG. 6 are mounted on the lower first housing 102.

  The lower first housing cover 104 (see FIG. 6) includes a horizontal relay duct 104a and a vertical relay duct 104b on the upper surface. The duct 105 is provided to connect the outflow duct 571 (see FIG. 11) of the dust collection unit 500 to the vertical relay duct 104b (see FIG. 6) via the packing 124.

  The vertical relay duct 104 b is provided to connect the duct 105 to the electric blower 106. Packings 125 and 126 are respectively attached to the entrances and exits of the lateral relay duct 104a (see FIG. 6).

  The horizontal relay duct 104a is used to connect the connecting portion 306 (see FIGS. 1, 3 and 10) of the suction hose portion 300 to the inlet 503 (see FIG. 11) of the dust collecting unit 500 via the packings 125 and 126. Is provided.

As a result, the flow path from the connection part 306 of the suction hose part 300 to the inlet 503 of the dust collection unit 500 through the horizontal relay duct 104a, the duct 105 and the vertical relay duct 104b from the outflow duct 571 of the dust collection unit 500 are connected. A flow path to the electric blower 106 is formed.
Further, the inlet of the duct 105 connected to the outlet from the outlet duct 571 of the dust collecting unit 500 and the inlet of the horizontal relay duct 104a from the connecting part 306 of the suction hose part 300 are formed on the same surface side. . This is because the dust collection unit 500 is likely to be stable because the inlet is pulled in the same direction by the suction force of the electric blower 106 when cleaning.
A terminal portion 104c (see FIG. 6) for connecting a terminal (not shown) of the connecting portion 306 to the cleaner body 100 is provided on a side surface of the horizontal relay duct 104a and is covered with a terminal cover 123 from the outside. The printed wiring board 120 of the vacuum cleaner main body 100 and the operation unit 305 of the suction hose unit 300 are connected by wiring via the terminal and the terminal unit 104c.

  The lower first housing 102 includes a wiring board case 102a (see FIGS. 5 and 8) extending rearward. A printed wiring board 120 is accommodated in the wiring board case 102a, and a case bottom plate 119 is mounted. As shown in FIG. 5, the lower first housing 102 includes a perforated plate 121 inserted between the electric blower 106 and the printed wiring board 120. The perforated plate 121 is a resin perforated plate.

  The lower first housing 102 (see FIG. 5) configured as described above is fixed to the front of the carriage 101, and the upper first housing 114 (see FIG. 6) having a hand handle 115 is mounted thereon. .

  On the other hand, the second casing 103 (see FIG. 4) installed in the center of the carriage 101 includes an upper opening 103a at the top, windows 103b on both sides, and a ring-shaped window frame 103c around the window 103b. .

  In addition, a lower flow path 138 (see FIG. 8) is formed between the bottom of the second housing 103 and the carriage 101 for flowing the air flow discharged from the electric blower 106 toward the third housing 107. Is done.

  Behind the carriage 101 are provided a cord reel 108 (see FIG. 7) for winding a power cord (not shown) so that it can be pulled out, and cord reel support plates 127, 128 for rotatably supporting the cord reel 108. They are covered by the third casing 107 (see FIG. 7).

  The third housing 107 accommodates the cord reel 108 so that the reel axis is parallel to the longitudinal direction of the carriage 101. Further, the third housing 107 includes an exhaust port 133 for discharging an air flow generated by the electric blower 106 and flowing through the lower flow path 138 to the rear of the cleaner body 100 via the cord reel 108. As a result, the power cord wound around the cord reel 108 is cooled when energized.

  A pair of arc-shaped reinforcing beams 109 shown in FIG. 4 are fixed to the carriage 101 so as to be coupled to the upper half of the ring-shaped window frame 103a of the second housing 103, and as shown in FIG. The first housing 114 and the third housing 107 are connected. As a result, the longitudinal rigidity of the cleaner body 100 is reinforced. The pair of reinforcing beams 109 together with the lower second housing 103 form a dust collection chamber 150 that houses the dust collection unit 500.

Then, as shown in FIG. 4, a ring-shaped wheel 140, that is, a ring-shaped wheel guide 111, a ring-shaped wheel body 110, a ring-shaped wheel cover 112, and a circle from both sides of the semicircular arc-shaped reinforcing beam 109 and the carriage 101. An arcuate decorative cover 113 is attached.
As shown in FIG. 8, the ring-shaped wheel main body 110 contacts the floor surface in front of the position of the center of gravity of the cord reel 108.

  As shown in FIGS. 8 to 10, the dust collecting unit 500 is disposed between the pair of reinforcing beams 109 from above the cleaner body 100 with respect to the cleaner body 100 configured in this manner. It is loaded into the second casing 103 through the upper opening 103a (see FIG. 4).

The free wheel 117 is provided at a position directly below the electric blower 106 so as to be rotatable and turnable on the outer bottom surface of the carriage 101 via a free frame 116 (see FIG. 4).
Thus, the electric blower 106 is in front, the center of gravity is forward, and the free wheel 117 is also provided on the lower side of the electric blower 106, so that the front of the cleaner main body 100 can be prevented from floating when cleaning. The movement of the vacuum cleaner main body 100 due to the pulling of the suction hose 301 can be easily followed.
As shown in FIG. 8, the free wheel 117 is in contact with the floor surface behind the center of gravity of the electric blower 106 and ahead of the ring-shaped wheel body 110.

  Thus, in the vacuum cleaner main body 100, the electric blower 106, the dust collection unit 500, and the cord reel 108 are arranged in a line in the longitudinal direction from the front of the carriage 101 (the connection side of the suction hose part 300), and the flow path is Since they are provided above and below them, the width of the vacuum cleaner main body 100 is minimized.

  FIG. 11 is an external perspective view of the dust collection unit 500. 12 is a cross-sectional view of the dust collection unit 500 taken along the line AA in FIG. The dust collection unit 500 includes a cup cover unit 570, a filter unit 550, an inner cylinder unit 530, and a bottomed cylindrical dust cup 501.

  The dust cup 501 is formed of a transparent or translucent resin so that the dust collection state is visible from the outside. As shown in FIG. 11, an inflow port 503 into which an air flow from the suction hose unit 300 (see FIG. 1) flows is provided on the front peripheral surface of the dust cup 501.

Referring to FIG. 10, the connection portion 306 of the suction hose portion 300 is bent from the center of the cleaner body 100 so that air flows straight into the inner circumferential surface of the cylindrical dust cup 501 from its tangential direction. doing.
Referring to FIG. 12, the inner cylinder unit 530 includes an upper cup cover 537 that houses the filter unit 550, a lower dust partition 535, and an inner cylinder 533 that connects between them. An opening is formed at the bottom of the cup cover 537 to which the inner cylinder 533 is connected. A slit-like outlet 533b is formed around the inner cylinder 533, and a mesh-like filter (not shown) is disposed at the outlet 533b. The dust partition 535 includes a flange portion 535 a having an outer diameter larger than that of the inner tube 533, a large-diameter tube portion 535 b surrounding the outer periphery of the flange portion, and a small-diameter tube portion 535 c whose lower end is in contact with the bottom center portion of the dust cup 501.

  When the electric blower 106 is operated, the air flow flows straight into the dust cup 501 in the circumferential tangent direction via the connecting portion 306 and the lateral relay duct 104a, and forms a high-speed swirling air flow in the dust cup 501.

Thereby, the dust contained in the airflow is centrifuged. Since the dust collecting unit 500 is installed so that the central axis of the swirling airflow to be formed faces the direction of gravity, the heavy dust among the centrifugally separated dust is accumulated below the flange portion 535a by the action of gravity. .
Here, the center axis of the swirling airflow of the dust collection unit 500 being directed in the direction of gravity does not require the center axis of the swirling airflow to be directly below, and the dust collection unit 500 is directed to the cleaner body 100 in the vertical direction. It only has to be arranged.

  A light thing is filtered with the mesh-like filter arrange | positioned in the outflow port 533b with an air flow. In addition, minute dust rises in the inner cylinder 533 through the outlet 533b and is filtered by the filter unit 550. The filter unit 550 includes a pleated filter in which a peak portion and a valley portion are continuous. The filtered air flow is sucked into the electric blower 106 through the outflow duct 571.

FIG. 13 is an explanatory view showing airflow paths in the cleaner body 100 shown in FIG.
As shown in the figure, the air flow from the suction hose 301 flows into the dust collection unit 500 through the connection portion 306 and above the electric blower 106.

  The inflowing air flow becomes a swirl flow in the dust cup 501 of the dust collection unit 500. After the dust collection is centrifuged, the air flow rises in the inner cylinder 533, passes through the filter unit 550, passes through the electric blower 106, and is below the dust collection unit 500 in the vertical direction of the carriage 101. Enters the lower flow path 138 formed in The swivel axis is slightly tilted rearward with respect to the vertical direction. When viewed from the side as shown in FIG. 13, the flow path flowing into the dust cup 501 from the connection portion 306 is substantially orthogonal to the pivot axis.

  The air flow passes through the wiring board case 102 a installed in the lower flow path 138 while cooling the printed wiring board 120, and then is distributed through the cord reel 108. The dispersed air flow is discharged to the outside from an exhaust port 133 provided on the back surface of the third housing 107.

  Therefore, the noise that tries to go out from the electric blower 106 in the air flow is attenuated by the long lower flow path 138 formed in the vertical direction of the carriage 101 below the dust collection unit 500, and the lower flow path. It is dispersed and absorbed by the wiring board case 102 a in 138 and the cord reel 108 in the third housing 107. Thereby, the noise of the electric blower 106 going out from the cleaner body 100 is effectively reduced.

  Further, as shown in FIG. 13, the flow path of the air flow is provided separately at the upper part and the lower part of the cleaner body 100 and is not provided at the side surface portion, so the lateral width of the cleaner body 100 is minimized. ing.

[Configuration of the universal frame]
FIG. 14 is an external perspective view of the free frame 116. 15A is a bottom view of the free frame 116, FIG. 15B is a side view in the front-rear direction, and FIG. 15C is a cross-sectional view taken along the line CC in FIG. (B) and (c) show the bogie 101 with a two-dot chain line, and the top and bottom are adapted to the state attached to the bogie 101. 16A is a bottom view of the free frame 116, FIG. 16B is a side view seen from the rear, and FIG. 16C is a sectional view taken along the line DD in FIG. (B) and (c) show the bogie 101 with a two-dot chain line, and the top and bottom are adapted to the state attached to the bogie 101.
As shown in FIGS. 15A and 16A, the free frame 116 has a shape in which a portion to which the free wheel 117 is attached is cut from a substantially circular bottom surface. A pivot shaft hole 116a for pivotally attaching to the carriage 101 is formed in the central portion. The carriage 101 is provided with a convex portion that fits into the turning shaft hole 116a, and the free frame 116 is turnably attached (see FIGS. 3, 4, and 8).
The left side in FIG. 15A and the upper side in FIG. 16A are the front side in the traveling direction. The universal wheel 117 is attached so as to be rotatable about a shaft (not shown) penetrating through two wheel shaft holes 116b formed at the rear end of the universal frame 116.
As shown in FIGS. 15 (b) and 15 (c), when viewed from the side in the traveling direction, the free frame 116 has a substantially flat upper side attached to the cleaner body 100, and the bottom side from the front side in the traveling direction. As it goes to the rear side, it gradually protrudes downward from the cleaner body 100. The ridge line on the bottom surface is formed so as to draw a gentle curve convex toward the bottom surface side. This ridge line is a ridge line of the curved surface of the central portion 116c. Note that there are partial spherical side portions 116d on the left and right sides of the central portion 116c. The curved surface formed by the central portion 116c corresponds to a specific embodiment of the second curved surface of the present invention.
The ridgeline is formed so as to be connected to the ridgeline at the front end of the carriage 101 in a state where the universal frame 116 is attached to the bottom surface of the cleaner body 100. This ridge line is a ridge line of the gentle first curved surface 101a formed from the lower part on the front side of the carriage 101 to the bottom surface (see FIGS. 3, 4 and 8).

  As described above, the electric vacuum cleaner of the present invention includes an electric blower disposed on the front side of the cleaner body and connected to the suction hose, and a power source disposed on the rear side of the cleaner body. A cord reel around which a cord is wound, a dust collecting unit that is disposed between the electric blower and the cord reel and collects dust sucked through the suction hose, and a pair that is disposed on both left and right sides of the dust collecting unit And a caster in contact with the floor surface behind the position of the center of gravity of the electric blower and in front of the main wheel.

Furthermore, the preferable aspect of this invention is demonstrated.
The caster is attached to a bottom surface of the cleaner body, and has a free frame that is freely supported with respect to the cleaner body and a wheel that is rotatably attached to the free frame. The first curved surface may be formed from the lower portion on the front side to the front end portion of the free frame on the bottom surface, and the second curved surface may be formed on the free frame from the front end portion to the portion where the wheel is attached. If it does in this way, when a vacuum cleaner main body passes a level | step difference, it can get over a level | step difference smoothly along a 1st curved surface and a 2nd curved surface. The central portion 116c of the free frame 116 in the above-described embodiment is an aspect of the second curved surface of the present invention.

  Further, when the caster and the main wheel are placed on a horizontal plane, the free frame rotates freely about a vertical axis with respect to the cleaner body, and the second curved surface is convex downward. It may descend as it advances from the front end to the rear end.

Further, the main wheel may be in contact with the floor surface in front of the position of the center of gravity of the cord reel. In this way, since the center of gravity of the cord reel is on the rear side of the main wheel, the moment of inertia when the cleaner body bends to the left and right is greater than in the case of being on the front side, and straightness is increased. Therefore, the travel of the cleaner body is stabilized.
Preferred embodiments of the present invention include combinations of any of the plurality of embodiments shown here.

More specifically, the cleaner body is pulled by the suction hose portion during the cleaning operation, and therefore, the suction hose portion is connected to the front of the cleaner body.
The power cord is wound around the cord reel, and all or a part of the power cord is pulled out during the cleaning operation. In particular, when only a part of the power cord is pulled out and the other part is wound around the cord reel, the mass of the cord reel and the power cord wound around the cord reel is a significant part of the total mass of the vacuum cleaner body. Occupy. This is because a material having a large mass such as copper is used for the power cord.
The dust collection unit may be, for example, a cyclone type that centrifuges dust, but is not limited thereto, and may be, for example, a paper bag type. The above-described embodiment is a cyclone type dust collection unit.
In the embodiment described above, the ring-shaped wheel corresponds to the main wheel of the present invention. In the above-described embodiment, the universal frame and the universal wheel correspond to the caster of the present invention.
In addition to the embodiments described above, there can be various modifications of the present invention. These modifications should not be construed as not belonging to the scope of the present invention. The present invention should include the meaning equivalent to the scope of the claims and all modifications within the scope.

DESCRIPTION OF SYMBOLS 1: Vacuum cleaner 100: Vacuum cleaner main body 101: Carriage 101a: 1st curved surface 102: Lower 1st housing | casing 102a: Wiring board case 103: 2nd housing | casing 103a: Upper opening 103b: Window, 103c: Window frame, 104: Lower first casing cover, 104a: Horizontal relay duct, 104b: Vertical relay duct, 104c: Terminal section, 105: Duct, 106: Electric blower, 107: Third casing, 108 : Cord reel, 109: Reinforcing beam, 110: Ring-shaped wheel body, 111: Ring-shaped wheel guide, 112: Ring-shaped wheel cover, 113: Arc-shaped decorative cover, 114: Upper first housing, 115: Hand handle 116: Swivel frame, 116a: Swivel shaft hole, 116b: Wheel shaft hole, 116c: Central part, 116d: Side part, 17: Swivel wheel, 119: Case bottom plate, 120: Printed wiring board, 121: Perforated plate, 122: Base, 123: Terminal cover, 124, 125, 126: Packing, 127, 128: Cord reel support plate, 131: Insert plug, 132: Brake button, 133: Exhaust port, 138: Lower flow path, 140: Ring-shaped wheel, 141: Center opening, 150: Dust collection chamber, 300: Suction hose part, 301: Suction hose, 302: Extension Pipe: 303: Suction part 304: Hand handle 305: Operation part 306: Connection part 500: Dust collecting unit 501: Dust cup 503: Inlet 530: Inner cylinder unit 533: Inner cylinder 533b : Outlet, 535: Dust partition, 535a: Flange, 535b: Large diameter Part, 535c: small diameter cylinder portion, 537: Cup cover, 550: filter unit 570: Cup cover unit, 571: outlet duct

Claims (4)

An electric blower disposed on the front side of the vacuum cleaner body and connected to the suction hose;
A cord reel on which a power cord is wound and disposed on the rear side of the cleaner body;
A dust collection unit that is disposed between the electric blower and the cord reel and collects dust sucked through the suction hose;
A pair of main wheels disposed on the left and right sides of the dust collection unit;
A vacuum cleaner comprising: a caster that is in contact with a floor surface behind a position of the center of gravity of the electric blower and in front of the main wheel. The caster is attached to the bottom surface of the cleaner body, and has a free frame that is freely supported with respect to the cleaner body and a wheel that is rotatably attached to the free frame,
In the cleaner body, a first curved surface is formed from a lower part on the front side to a front end part of the free frame on the bottom surface,
The vacuum cleaner according to claim 1, wherein a second curved surface is formed on the free frame from a front end portion to a portion to which the wheel is attached. When the caster and the main wheel are placed on a horizontal plane,
The universal frame rotates freely about a vertical axis with respect to the cleaner body; and
The vacuum cleaner according to claim 2, wherein the second curved surface is convex downward and descends from the front end to the rear end.   The vacuum cleaner according to any one of claims 1 to 3, wherein the main wheel is in contact with the floor surface in front of the position of the center of gravity of the cord reel.