ELECTRIC CLEANER

Abstract

 Traveling wheels 51 are provided rotatably at positions on both sides of a main body case 25 below the center of gravity of a cleaner main body 13. A rear wheel 52 which can advance to and withdraw from a floor surface F side is provided posterior to rotary shafts 57 of the traveling wheels 51 of the main body case 25. The rear wheel 52 is energized in a direction of advancing to the floor surface F so as to become contactable with the floor surface F in an advanced state. The rear wheel 52 comes into contact with the floor surface F at a proper contact pressure, so that without deteriorating the turnability of the cleaner main body 13, straight traveling performance can be made higher than in the case where the cleaner main body travels only by the traveling wheels 51.

Description

Field

[0001] The present invention relates to an electric vacuum cleaner including traveling wheels provided rotatably on both sides of a main body case.

Background

[0002] Conventionally, this type of electric vacuum cleaner includes a cleaner main body as a main body part including a main body case, an electric blower housed in the main body case, and a dust collecting part which is communicatively connected to the suction side of the electric blower and disposed in the main body case. On both side portions of the main body case, traveling wheels are axially supported rotatably. At the substantially central position in the left-right width direction anterior to the rotary shafts of the traveling wheels of the main body case, a turning wheel which comes into contact with a floor surface as a surface to be cleaned is disposed turnably. Further, at the substantially central position in the left-right width direction posterior to the rotary shafts of the traveling wheels of the main body case, a rear wheel is disposed rotatably which comes into contact with the floor surface when the front side is lifted to get over an obstacle such as a doorsill (for example, refer to Patent Document 1).

Citation List

Patent Literature

[0003] 

[PTL 1] Patent Citation 1: Japanese Laid-Open Patent Publication No. 4-343815 (page 2, Fig. 4)

Summary of Invention

Technical Problem

[0004] In the above-described electric vacuum cleaner, the turning wheel is disposed so as to always project to the floor surface side from the cleaner main body, so that when the cleaner main body turns, the turning wheel becomes resistant and turnability of the cleaner main body is deteriorated.

[0005] On the other hand, if the turning wheel or the like is not provided and only the traveling wheels are provided, straight traveling performance is deteriorated although turnability of the cleaner main body on a floor surface can always be secured.

[0006] The present invention has been developed in view of these circumstances, and an object thereof is to provide an electric vacuum cleaner which can improve straight traveling performance without deteriorating the turnability of the main body part.

Solution to Problem

[0007] An electric vacuum cleaner of the present invention includes traveling wheels provided rotatably at positions on both sides of the main body case below the center of gravity of the main body part, and a rear wheel which is provided posterior to the rotary shafts of the traveling wheels of the main body case so as to advance to and withdraw from a surface to be cleaned, and is energized in a direction of advancing to the surface to be cleaned, and can come into contact with the surface to be cleaned in an advanced state.

Advantageous Effects of Invention

[0008] According to the present invention, by energizing a rear wheel which can freely advance to and withdraw from a surface to be cleaned on the side posterior to the rotary shafts of the traveling wheels and can come into contact with the surface to be cleaned in an advanced state in a direction of advancing toward the surface to be cleaned, the rear wheel comes into contact with the surface to be cleaned at a proper contact pressure, so that without deteriorating the turnability of the main body part, the straight traveling performance can be made higher than in the case where the cleaner travels by using only the traveling wheels.

Brief Description of the Drawings

[0009] 

Fig. 1 is a partially cut-away side view of a main body part of an electric vacuum cleaner according to an embodiment of the present invention.

Fig. 2 (a) is an explanatory sectional view showing a state where a rear wheel is withdrawn to the same main body part, and Fig. 2 (b) is an explanatory sectional view showing a state where the rear wheel is advanced from the same main body part.

Fig. 3 is a perspective view of the same main body part from below.

Fig. 4 is a perspective view showing a state where a lid body of the same main body part is opened.

Fig. 5 is a perspective view showing the same electric vacuum cleaner.

Description of Embodiments

[0010] A configuration of an electric vacuum cleaner according to an embodiment of the present invention will be described with reference to Fig. 1 to Fig. 5.

[0011] In Fig. 5, the reference numeral 11 denotes a so-called canister type electric vacuum cleaner, and this electric vacuum cleaner 11 includes a tubular part 12, and a cleaner main body 13 as a main body part to which the tubular part 12 is removably connected.

[0012] The tubular part 12 includes a connecting tube part 15 having a tip end side bent forward with respect to the base end side to be connected to the cleaner main body 13, a hose body 16 with flexibility to be communicatively connected to the tip end side of the connecting tube part 15, a hand operation part 17 provided on the tip end side of the hose body 16, an extension tube 18 to be removably connected to the tip end side of the hand operation part 17, and a floor brush 19 as a suction port body to be removably connected to the tip end side of the extension tube 18.

[0013] On the hand operation part 17, a grip part 21 projects to the hose body 16 side, and on this grip part 21, a plurality of operation setting buttons 22 are provided.

[0014] As shown in Fig. 1 and Fig. 4, the cleaner main body 13 includes a main body case 25, and inside the main body case 25, a partition wall 26 is provided, and on the rear side of the partition wall 26, an electric blower chamber not shown housing an electric blower 27 and a cord reel chamber not shown housing a cord reel not shown around which a power cord 31 is wound are partitioned, and on the front side of the partition wall 26, a main body dust collecting chamber 35 which is communicatively connected to the suction side of the electric blower 27 via a communication port not shown provided in the partition wall 26 is partitioned, and in the main body dust collecting chamber 35, a dust collecting cup 36 as a dust collecting device is removably provided.

[0015] The main body case 25 is made of, for example, a synthetic resin, and includes a lower case 41 opened upward, an upper case 42 as an upper rear portion of the lower case 41 and covering the electric blower chamber and the cord reel chamber, and a lidbody 43 axially supported turnably in the up-down direction with respect to the upper case 42 or the lower case 41 and capable of opening and closing the main body dust collecting chamber 35.

[0016] The lower case 41 has, on its rear side, a rear portion curved surface 45 curved to the upper rear side on the lower surface facing a floor surface F as a surface to be cleaned, a flat surface 46 continuing to the front side of the rear portion curved surface 45 at the substantially central position in the front-rear direction, and on the front side of the flat surface 46, a front portion curved surface 47 continuing to the front side of the flat surface 46 and curved in a substantially arc shape to the upper front side. On both sides of the rear portion curved surface 45 of the lower case 41, traveling wheels 51 with large diameters for traveling of the cleaner mainbody 13 are axially supported rotatably. Further, on the rear portion curved surface 45 of the lower case 41, a rear wheel 52 is provided. On the front portion curved surface 47 of the lower case 41, a front wheel 53 is provided rotatably.

[0017] Each traveling wheel 51 includes, as shown in Fig. 1 to Fig. 3, a wheel portion 55 as a substantially disk-shaped traveling wheel main body, and a roller portion 56 attached to cover the entire outer periphery of the wheel portion 55.

[0018] The wheel portion 55 is made of, for example, a hard synthetic resin, and the central portion serves as a rotary shaft 57 axially supported rotatably on the lower case 41.

[0019] The roller portion 56 is a portion which comes into contact with the floor surface F, and is made of a synthetic resin such as rubber or elastomer softer than the wheel portion 55.

[0020] The rear wheel 52 includes an axially supporting portion 61 axially supported turnably on the lower case 41 and a rear wheel main body 62 axially supported rotatably on the axially supporting portion 61. The rear wheel 52 is attached to the inside of a recessed attaching part 63 attached to the lower case 41, and can advance to and withdraw from the lower case 41 (main body case 25). Further, the rear wheel 52 is disposed at the substantially central position in the left-right width direction of the cleaner main body 13 (main body case 25).

[0021] The axially supporting portion 61 is formed to have a quadrilateral shape in a plan view and a triangular shape in a side view, and is axially supported at its front end portion on a position on the front portion of the attaching part 63 and posterior to the rotary shafts 57 of the traveling wheels 51 of the lower case 41, and axially supports the rear wheel main body 62 on the rear end side. Therefore, the axially supporting portion 61 is arranged so that the rear side moves up and down according to turning as shown in Fig. 2(a) and Fig. 2(b). The position of the front end side of the axially supporting portion 61 axially supported turnably on the lower case 41 is lower than the line L connecting the central position of the rotary shaft 57 of the traveling wheel 51 and the center of the rotary shaft of the rear wheel main body 62 in a side view. The inclination of the line L differs depending on the turning position of the axially supporting portion 61, and the inclination increases as the axially supporting portion 61 advances to the floor surface F side, and in the present embodiment, it is assumed that the front end side of the axially supporting portion 61 is axially supported on the lower case 41 at a position lower than the line L in the whole turning range of the axially supporting portion 61. Further, the axially supporting portion 61 is energized by a coil spring 65 as an energizing means so that the rear side projects downward, that is, toward the floor surface F side. This coil spring 65 is disposed at a position anterior to the rear wheel main body 62 and posterior to the front end portion of the axially supporting portion 61, that is, posterior to the portion where the axially supporting portion 61 is axially supported turnably on the lower case 41. This coil spring 65 is preferably as far as possible from the portion where the axially supporting portion 61 is axially supported turnably on the lower case 41, that is, as far as possible from the front end portion of the axially supporting portion 61 so that the rear wheel 52 is easily made project from the main body case 25.

[0022] The rear wheel main body 62 has a horizontally-long columnar shape having an axial direction along the left-right direction, and to its outer peripheral surface, a raised-fabric cloth 67 is attached. By energizing the rear side of the axially supporting portion 61 to the floor surface F side by the coil spring 65, the rear wheel main body 62 is arranged to always be in elastic contact with the floor surface F when the cleaner main body 13 travels on the floor surface F.

[0023] The attaching part 63 is fitted to a hole portion 69 having a quadrilateral shape in a plan view formed in the lower case 41.

[0024] The front wheel 53 includes a front wheel axially supporting portion 71 fixed to the lower case 41, and a front wheel main body 72 axially supported rotatably on the front wheel axially supporting portion 71. This front wheel 53 is disposed at a substantially central position in the left-right width direction of the cleaner main body 13 (main body case 25) substantially symmetrical to the rear wheel 52 with respect to a straight line connecting the central axes of the rotary shafts 57 of the traveling wheels 51 and 51. In other words, the distance in the front-rear direction from the rotary shafts 57 of the traveling wheels 51 to the central axis of the front wheel 53 is set to be substantially equal to the distance in the front-rear direction from the rotary shafts 57 of the traveling wheels 51 to the central axis of the rear wheel 52. Specifically, the front wheel 53 and the rear wheel 52 are disposed at the front and rear sides at distances substantially equal to each other from the rotary shafts 57 of the traveling wheels 51. Further, this front wheel 53 is arranged so that the position of the lower end side is higher than the position of the lower end portion of the roller portion 56 as the lower end portion of the traveling wheel 51, and does not come into contact with the floor surface F in a normal traveling state, and comes into contact with a bump D, etc., only when getting over the bump D.

[0025] The front wheel axially supporting portion 71 includes a pair of axial support plates 74 and 74 projecting downward from the lower case 41.

[0026] The front wheel main body 72 has a horizontally-long columnar shape having an axial direction along the left-right direction, and both end portions of the front wheel main body are axially supported on the axial support plates 74 and 74, and to the outer peripheral surface, a raised-fabric cloth 76 is attached. In addition, the front wheel main body 72 has a width dimension substantially equal to the rear wheel main body 62.

[0027] In the upper case 42, a number of exhaust ports not shown which are communicatively connected to the downstream side of the electric blower chamber (cord reel chamber) are opened, and in a lateral side of these exhaust ports, a cord leading-out port 77 for leading the power cord 31 to the outside of the main body case 25 is opened. On the upper portion of the upper case 42, a handle 78 as a main body grip part for gripping the cleaner main body 13 is provided turnably in the front-rear direction. Further, on the upper portion of the upper case 42, a cord rewind button 79 which enables rewinding of the power cord 31 from the cord leading-out port 77 by rotating the cord reel is provided.

[0028] The lid body 43 has a rear end side axially supported turnably, and a front end portion provided with a clamp 81 for engaging and disengaging the lid body 43 with and from the lower case 41. On this lid body 43, a slope portion 82 sloping to the front upper side is formed to have a circular shape, and on the slope portion 82, a rotating part 84 including a main body suction port 83 to which the connecting tube part 15 of the tubular part 12 is connected is provided rotatably in the circumferential direction.

[0029] The electric blower 27 operates in a predetermined operation mode set by the setting button 22 and suctions dust together with air via the tubular part 12 by being supplied with power from a power supply via the power cord 31, and is, for example, a heavy load heaviest in weight among various members disposed in the main body case 25. This electric blower 27 is disposed inside the electric blower chamber so that the front side becomes the suction side and the rear side becomes the exhaust side, and is positioned eccentrically to the rear side as a whole of the main body case 25. This electric blower 27 may be at least partially covered by, for example, a cover body.

[0030] The cord reel is a heavy load positioned at the lateral side of the electric blower 27 and disposed inside the cord reel chamber, and positioned eccentrically to the rear side as a whole of the main body case 25.

[0031] As a result, the center of gravity of the cleaner main body 13 is positioned on the rotary shafts 57 of the traveling wheels 51.

[0032] On the other hand, as shown in Fig. 1, the dust collecting cup 36 traps dust included in suction air by centrifugal separation (cyclone separation), and includes a cup main body part 85 as an outer case as a dust collecting device main body, an inside case 86 as an inner case provided removably inside the cup main body part 85, a cup lid 87 as a lid part provided turnably on the cup main body part 85, and a filter part 88 removably attached to the cup main body part 85. Inside the cup main body part 85 of the dust collecting cup 36, a rough dust trapping chamber 91 which is a first dust collecting part as a dust collecting chamber for trapping rough dust such as dust balls, a filter attaching part 92 to which the filter part 88 is attached, a communication chamber 93 as an air path communicatively connected to the rough dust trapping chamber 91, and a fine dust trapping chamber 94 serving as a second dust collecting part that is a dust storing chamber as a dust collecting chamber positioned below the filter attaching part 92, are partitioned.

[0033] At the lower end portion of the cup main body part 85, a dust disposal port 95 which is communicatively connected to the rough dust trapping chamber 91 and the fine dust trapping chamber 94 and is opened and closed by the cup lid 87 is formed. On a side portion of the cup main body part 85, an open/close operation button 96 for opening and closing the cup lid 87 is disposed. On the upper portion of the cup main body part 85, a cylindrical suction tube part 98 which partitions a circular air suction port 97 communicatively connected to the rough dust trapping chamber 91 is formed.

[0034] To the entire dust disposal port 95, a packing 99 as a sealing member is attached.

[0035]  The air suction port 97 circulates air including dust suctioned via the tubular part 12 as shown by the arrow A inside the rough dust trapping chamber 91, and is arranged to be connected airtightly to the downstream side of the main body suction port 83 by closing the lid body 43 in a state where the air suction port is attached to the main body dust collecting chamber 35.

[0036] The inside case 86 partitions a communication chamber 93 between the inside case and the cup main body part 85, and communication openings 101 which communicatively connect the rough dust trapping chamber 91 and the communication chamber 93 are opened in both side portions (only one is shown), and to each communication opening 101, a side portion filter 102 as a filter is attached. Further, on the upper portion of the inside case 86, a cylindrical communication tube part 103 to be connected airtightly to the lower end side as the downstream side of the suction tube part 98 is formed. Further, on the front portion of the inside case 86, a front wall part 104 projecting so as to cross a part of the air flow along the arrow A suctioned from the air suction port 97 into the rough dust trapping chamber 91 is formed. In the rear portion of the inside case 86, a filter attaching opening 105 as a rear portion opening which communicatively connects the rough dust trapping chamber 91 and the communication chamber 93 to the filter attaching part 92 is opened, and to this filter attaching opening 105, amain filter 106 as a filtration filter is attached. Further, below the filter attaching opening 105 of the rear portion of the inside case 86, a ventilation opening 107 which communicatively connects the rough dust trapping chamber 91 and the fine dust trapping chamber 94 is formed, and to this ventilation opening 107, a lower portion filter 108 as a filter is attached. Above the ventilation opening of the rear portion of the inside case 86, a slope wall part 111 is formed to project to the rear lower side, and in this slope wall part 111, a plurality of openings 112 which communicatively connect the fine dust trapping chamber 94 and the filter attaching part 92 are opened in the left-right width direction, and these openings 112 are opened and closed by flap-shaped shutters 113 as closing members.

[0037] The front wall part 104 projects from the front side to the rear side and is opposed to the dust disposal port 95, and has a communication opening 115 which communicatively connects the rough dust trapping chamber 91 and the communication chamber 93, and to this communication opening 115, a ventilation filter 116 as a filter is attached.

[0038] The main filter 106 is a meshed filtration filter made of, for example, metal and having no unevenness on the upstream surface side and the downstream surface side, and is disposed at a position opposed to (facing) the lower end of the communication tube part 103 on the downstream side of the air suction port 97, and a suction air suctioned from the air suction port 97 is directly blown aslant to the main filter.

[0039] The ventilation opening 107 is a vent hole for making smooth the actuation of the shutters 113 by suctioning air from the rough dust trapping chamber 91 side to the fine dust trapping chamber 94 side when the shutters 113 are actuated by a negative pressure generated by driving of the electric blower 27.

[0040] The upper end portion of each shutter 113 is axially supported rotatably at a position on the upper end front side of the openings 112, and the lower end side is a free end.

[0041] The cup lid 87 is made of, for example, a synthetic resin and has, on one side, a pair of ribs not shown for axially supporting the cup lid 87 turnably on one side portion of the cup main body part 85, and has, on the other side, a latching projection not shown having a claw shape as a latch part for latching the cup lid 87 onto the cup main body part 85 side. Further, on this cup lid 87, a packing receiving portion 121 with which a packing 99 on the lower portion of the dust disposal port 95 is brought into pressure contact is formed.

[0042] The filter part 88 is a filter unit including, as a filter, a surface dust collecting filter which is a fine dust filter, that is, a pleated filter 123, and a filter holding frame 124 which holds the pleated filter 123.

[0043] The pleated filter 123 traps fine dust which was not trapped by the filters 102, 106, and 116, and mountain portions projecting forward and valley portions projecting rearward are alternately formed in the width direction in a straight line along the up-down direction to form a pleated shape. In the rear of the pleated filter 123, a dust shaking-off part 125 as a dust removing means which removes fine dust trapped by the pleated filter 123 by vibrating the pleated filter 123 is disposed.

[0044] The filter attaching part 92 is a space formed to have a frame shape at the rear portion of the cup main body part 85, and the rear end portion thereof becomes a dust collecting cup exhaust port 128 as a dust collecting device exhaust port having a substantially quadrilateral shape to be closed by the filter part 88.

[0045] The communication chamber 93 is an air path through which a part of air suctioned into the rough dust trapping chamber 91 flows to the pleated filter 123 without passing through the main filter 106, and is partitioned between the cup main body part 85 and the inside case 86, and communicatively connected between the downstream side of the communication opening 101 (side portion filter 102) and the communication opening 115 (ventilation filter 116) and the filter part 88 on the suction side of the electric blower 27.

[0046] The fine dust trapping chamber 94 is a space for storing fine dust removed from the pleated filter 123 by the dust shaking-off part 125 via the openings 112.

[0047] Next, operations of the above-described embodiment will be described.

[0048] When cleaning, first, an operator opens the lid body 43 of the cleaner main body 13, attaches the dust collecting cup 36 to the main body dust collecting chamber 35, and closes the lid body 43. At this time, the operator communicatively connects the hose body 16 to the main body suction port 83 on the upper side via the connecting tube part 15, and communicatively connects the extension tube 18 and the floor brush 19 to the tip end side of the hose body 16 in order.

[0049] Further, the operator pulls the power cord 31 out from the cleaner main body 13 and plugs it in a socket not shown.

[0050]  Thereafter, when the operator grips the grip part 21 and operates a predetermined setting button 22, the electric blower 27 is driven according to an operation mode set by the setting button 22. According to driving of the electric blower 27, shutters 113 are adsorbed to the front face side of the slope wall part 111 by air that passed through the ventilation opening 107 (lower portion filter 108) to close the openings 112, so that fine dust trapped in the fine dust trapping chamber 94 is not suctioned out from the openings 112 to the filter attaching part 92 (pleated filter 123) side.

[0051] Next, the operator makes the floor brush 19 travel back and forth on the floor surface F while making the cleaner main body 13 travel on the floor surface F by gripping the grip part 21, and accordingly, dust is suctioned together with air from the tip end side of the floor brush 19 by a negative pressure generated by the electric blower 27.

[0052] At this time, by energizing the rear side of the axially supporting portion 61 so as to turn down by the coil spring 65, the rear wheel 52 advances to the floor surface F side from the lower case 41 and the raised-fabric cloth 67 of the rear wheel main body 62 comes into contact with the floor surface F, so that the cleaner main body 13 is supported at three points of the rear wheel 52 and the traveling wheels 51 and stably travels straight. The rear wheel main body 62 is in elastic contact with the floor surface F due to the coil spring 65, so that vibrations in the up-down direction caused during traveling of the cleaner main body 13 are absorbed by withdrawal of the rear wheel 52 into the attaching part 63 of the main body case 25 in response to contraction of the coil spring 65 according to the vibrations, and the rear wheel main body 62 comes into contact with the floor surface F at a proper contact pressure. Further, when the cleaner main body 13 goes over a bump D such as an obstacle during traveling, the front wheel main body 72 of the front wheel 53 comes into contact with the bump D and makes it easy to get over the bump D, and the rear side of the axially supporting portion 61 of the rear wheel 52 turns up along the upper surface of the bump D, etc., against energization of the coil spring 65, and accordingly, the rear wheel 52 (rear wheel main body 62) is prevented from being caught on the bump D.

[0053] When the operator pulls the tubular part 12 laterally with respect to the cleaner main body 13, one traveling wheel 51 rotates forward and the other traveling wheel 51 rotates reversely, and accordingly, the cleaner main body 13 turns following the pulling direction of the tubular part 12.

[0054] Air suctioned together with dust from the floor brush 19 becomes suction air, and carries dust from the main body suction port 83 to the dust collecting cup 36 via the extension tube 18 and the hose body 16 (connecting tube part 15).

[0055] In this dust collecting cup 36, suction air which is suctioned from the main body suction port 83 to the air suction port 97 is suctioned substantially straight to the rough dust trapping chamber 91 along the opening direction of the air suction port 97 via the suction tube part 98 and the communication tube part 103, and directly blown aslant to the upstream side surface of the main filter 106 to always remove and drop dust adhering to the main filter 106.

[0056] Further, the suction air blown to the main filter 106 turns to the front portion upper side from the rear portion lower side in the arrow A direction inside the rough dust trapping chamber 91 while removing dust adhering to the main filter 106, and then passes through the main filter 106 and flows to the filter attaching part 92 while dust is trapped from the suction air. By this turning, rough dust such as dust balls included in the suction air is centrifugally separated (cyclone-separated) by the centrifugal force, and stored while being compressed toward the lower side of the front wall part 104.

[0057] From a part of the suction air, dust is trapped when it passes through the side portion filter 102 and the ventilation filter 116 and flows to the communication chamber 93.

[0058] From the suction air which has passed through the main filter 106 or the communication chamber 93 (side portion filter 102 and the ventilation filter 116), fine dust which is not trapped by the filters 102, 106, and 116 is trapped when it passes through the pleated filter 123.

[0059] Thereafter, the suction air is suctioned into the electric blower 27 via the communication port of the partition wall 26, and passes through the electricblower 27 and becomes exhaust air, and is exhausted to the outside of the cleaner main body 13 from the exhaust port of the main body case 25.

[0060] To finish cleaning, the operator operates a predetermined setting button 22 to stop the electric blower 27. In response to this stop of the electric blower 27, the shutters 113 turn to the front lower side due to their own weights to open the openings 112. In this state, the dust shaking-off part 125 operates for a predetermined time to drop and remove fine dust trapped by the pleated filter 123, and the fine dust is trapped in the fine dust trapping chamber 94 via the openings 112. The dust shaking-off part 125 may also be operated, for example, immediately before starting the electric blower 27.

[0061] Thereafter, the operator operates the cord rewind button 79 to rewind the power cord 31 unplugged from the socket around the cord reel from the cord leading-out port 77.

[0062] When trapped dust not less than a predetermined amount is accumulated in the dust collecting cup 36, the operator opens the lid body 43 of the cleaner main body 13, removes the dust collecting cup 36 from the main body dust collecting chamber 35, and operates the open/close operation button 96 to open the cup lid 87 above a garbage box, etc. , and accordingly, rough dust trapped in the rough dust trapping chamber 91 and fine dust trapped in the fine dust trapping chamber 94 are disposed of from the dust disposal port 95.

[0063] Further, when the side portion filter 102 and the ventilation filter 116, etc., are clogged, the operator pulls out the inside case 86 downward from the dust disposal port 95 and removes it from the cup main body part 85, and maintains the filters 102 and 116. At this time, if the main filter 106 is clogged due to long-term continuous use although it is rarely clogged, the operator removes dust from the filter.

[0064] Thereafter, the operator closes the cup lid 87 in a state where the inside case 86 is attached to the cup main body part 85, attaches the dust collecting cup 36 again to the main body dust collecting chamber 35 of the cleaner main body 13, and closes the lid body 43.

[0065] As described above, in the embodiment described above, the rear wheel 52 which can advance to and withdraw from the floor surface F and can come into contact with the floor surface F in an advanced state at a position posterior to the rotary shafts 57 of the traveling wheels 51 is energized by the coil spring 65 in a direction of advancing to the floor surface

F.

[0066] Therefore, for example, when the rear wheel or the like is provided so as to project from the main body case, while the straight traveling performance of the cleaner main body 13 can be improved, the rear wheel becomes resistant and deteriorates the turnability when the cleaner main body 13 turns, and on the other hand, according to the embodiment described above, the rear wheel 52 comes into elastic contact with the floor surface F, so that the rear wheel 52 comes into contact with the floor surface F at a proper contact pressure by advancing and withdrawing as appropriate, so that, without deteriorating the turnability of the cleaner main body 13 by the traveling wheels 51, the straight traveling performance can be made higher than in the case where the cleaner main body travels only by the traveling wheels 51.

[0067] Further, only one rear wheel 52 is provided at the central position in the left-right width direction of the cleaner main body 13, so that the frictional resistance with the floor surface F can be minimized while the straight traveling balance is maintained, and turnability can be secured.

[0068] The rear wheel 52 is always in elastic contact with the floor surface F in the traveling state where the traveling wheels 51 of the cleaner main body 13 are grounded on the floor surface F, so that the rear wheel 52 does not float up from the floor surface F and the straight traveling performance can be reliably improved.

[0069] Further, by axially supporting the rear wheel main body 62 of the rear wheel 52 on the axially supporting portion 61 axially supported on the main body case 25 turnably in the direction of advancing and withdrawing the rear wheel main body 62 to and from the floor surface F at a position anterior to the rear wheel main body 62, when the cleaner main body 13 travels forward, the axially supporting portion 61 is hardly caught on the floor surface F and the rear wheel 52 more easily turns in comparison with the case where, for example, the turning shaft of the axially supporting portion is positioned posterior to the rear wheel main body.

[0070] The axially supporting portion 61 is axially supported lower than the line connecting the rotary shaft 57 of the traveling wheel 51 and the rotary shaft of the rear wheel main body 62 in a side view, so that the inclination angle of the axially supporting portion 61 with respect to the floor surface F becomes smaller, the contact resistance between the rear wheel main body 62 and the floor surface F is reduced, and the rear wheel 52 turns more easily.

[0071] Further, by providing the front wheel 53 rotatably anterior to the rotary shafts 57 of the traveling wheels 51 of the main body case 25, in the case where a bump D such as an obstacle is on the floor surface when the cleaner main body 13 travels forward, the front wheel 53 collides with the bump D and rotates, and accordingly, the cleaner main body more easily gets over the bump D, so that the cleaning operability is improved.

[0072] Further, the roller portions 56 which come into contact with the floor surface F of the traveling wheels 51 are made of a soft synthetic resin, and the rear wheel 52 has a raised-fabric cloth 67 on the outer peripheral surface of the rear wheel main body 62 which comes into contact with the floor surface F, and accordingly, the traveling wheels 51 hardly slip on the comparatively flat floor surface F, and the rear wheel 52 more easily slides on the floor surface F, so that while the straight traveling performance is secured by the rear wheel 52, the rear wheel 52 hardly becomes more resistant when turning, so that the turnability can be improved.

[0073] By providing the raised-fabric cloth 67 on the outer periphery of the rear wheel main body 62 of the rear wheel 52 and providing the raised-fabric cloth 76 on the outer periphery of the front wheel main body 72 of the front wheel 53, dust on the floor surface F can be wiped off by these raised-fabric cloths 67 and 76.

[0074] In the embodiment described above, pluralities of rear wheels 52 and front wheels 53 may be provided. In this case, in order to stably support the cleaner main body 13, the rear wheels and front wheels are preferably disposed substantially uniformly in the left-right width direction, that is, symmetrically in the left-right width direction.

[0075] The front wheel 53 may not be provided as long as the cleaner main body can get over the bump D on the floor surface F.

[0076] As a dust collecting device, the dust collecting cup 36 for centrifugal separation of dust is used, however, a configuration in which dust is collected in a paper pack or a configuration in which dust is collected by linear separation, etc., can be arbitrarily selected. Therefore, the internal configuration, etc., of the cleaner main body 13 are not limited to the configuration described above.

Industrial Applicability

[0077] The present invention can be preferably applied to, for example, domestic vacuum cleaners.

Reference Signs List

[0078] 

11

Electric vacuum cleaner

13

Cleaner main body as main body part

25

Main body case

27

Electric blower

51

Traveling wheel

52

Rear wheel

53

Front wheel

57

Rotary shaft

61

Axially supporting portion

62

Rear wheel main body

67

Raised-fabric cloth

F

Floor surface as surface to be cleaned

Claims

1. An electric vacuum cleaner comprising:

a main body part including a main body case and an electric blower housed in the main body case;

traveling wheels provided rotatably at positions on both sides of the main body case below the center of gravity of the main body part; and

a rear wheel which is provided so as to advance to and withdraw from a surface to be cleaned posterior to the rotary shafts of the traveling wheels of the main body case, and is energized in a direction of advancing to the surface to be cleaned, and can come into contact with the surface to be cleaned in an advanced state.

2. The electric vacuum cleaner according to Claim 1, wherein the rear wheel is always in elastic contact with the surface to be cleaned in a traveling state where the traveling wheels of the main body part are grounded on the surface to be cleaned.

3. The electric vacuum cleaner according to Claim 1 or 2, wherein
the rear wheel includes:

a rear wheel main body contactable with the surface to be cleaned; and

an axially supporting portion which axially supports the rear wheel main body rotatably, and is axially supported at a position anterior to the rear wheel main body on the main body case turnably in a direction of advancing and withdrawing the rear wheel main body to and from the surface to be cleaned.

4. The electric vacuum cleaner according to Claim 3, wherein the axially supporting portion is axially supported lower than the line connecting a rotary shaft of the traveling wheel and a rotary shaft of the rear wheel main body in a side view.

5. The electric vacuum cleaner according to any one of Claims 1 to 4, comprising:

a front wheel provided rotatably anterior to the rotary shafts of the traveling wheels of the main body case.

6. The electric vacuum cleaner according to any one of Claims 1 to 5, wherein
at least portions of the traveling wheels which come into contact with the surface to be cleaned are made of a resin, and
the rear wheel has a raised-fabric cloth on a portion which comes into contact with the surface to be cleaned.

Drawing