EP2465647A2 - Hand tool machine with air circulation element - Google Patents

Abstract

The tool (100) has a housing wall (110), and a fan device having air suction unit (114) and air outlet (116). The fan device has an air guide element (130) and discharge chambers (142,143). The surface contours (161,162) of housing wall are extended to downstream side (124) of the air suction unit. An air guide element (131) is shaped such that the cross-sectional area (Q) of discharge chamber set transverse to the downstream direction (127) of air suction unit, increases with the increasing distance from the downstream side in downstream direction.

Description

Technical area

The invention relates to a hand tool according to the preamble of claim 1, which has a housing wall and a fan device with an air intake means and an air outlet in the housing wall. In particular, the invention relates to a hand tool machine, in which an air guide element is additionally arranged between the housing wall and the air intake means, which delimits a diffuser-like outflow space.

State of the art

By the term hand tool machine is meant, for example, an electrically operated hand tool machine, such as a diamond machine, a drill or chisel hammer, a screwdriver, a cordless drill and the like.

From the publication DE 103 58 027 A1 is known that for cooling a hand tool cooling air sucked by means of an air intake by air inlets in the housing of the power tool and passed over to be cooled elements of the power tool, such as the electric motor and / or the transmission and then through air outlets, which are also placed in the housing, is blown out.

Such a prior art hand tool is in Fig. 1 and in Fig. 2 shown schematically.

It is desirable to ensure sufficient cooling of the components to be cooled of the power tool even with a compact design of the power tool.

Presentation of the invention

At this point, the invention begins, whose task is to provide a hand tool with a streamlined air duct for discharging the sucked by the air intake and heated by the waste heat of the components to be cooled components of the power tool air.

This object is achieved by the invention by means of a hand tool of the type mentioned, in which the features of the characterizing part of claim 1 are provided according to the invention.

The invention is based on the consideration that in the previously known from the prior art hand tool no guidance of the air from the air intake to the air outlet out and so far there is Fehlanströmungen the air outlet, which ultimately a rapid flow of sucked air to be cooled elements counteract the hand tool and therefore the cooling is impaired.

In departure from the hand tool known from the prior art, an air guide element is additionally provided in the fan device, which laterally delimits a diffuser-like outflow space.

The invention has recognized that the air flow impairment and concomitant refrigeration impairment presented above may be based on a variety of reasons. For example, in the previously known hand-held power tool, the drive unit and the output unit are connected to one another via screwed connections. These glands are arranged in the region of the gap between the fan, which is placed between the drive and output unit, and the housing wall. The fittings hinder, especially in a compact design, a quick and smooth escape of air from the gap. In addition, such fittings must be enclosed in a housing which can be provided with air outlets only in a partial area, because e.g. a drill stand or a handle abut directly or other ergonomic reasons do not allow further air outlets.

The conditional by the fittings deterioration of the air flow in the prior art hand tool occurs even when the fan between a handle of the prior art hand tool and the drive unit of Prior handheld power tool is positioned, as well as the handle and the drive unit are connected to each other via screw and a positioned between the handle and drive unit fan is hindered by this when blowing the air.

The impairment of the air flow may be further affected by a particular design, which does not allow, for example, a round or asymmetrical housing shape. In addition, the air outlet may be designed so that it is not adapted to the direction of the air flowing out of the air intake means and it can come as far as a false flow.

The invention has further recognized that a previously known from the prior art solution to compensate for the illustrated impairment of air flow, namely the provision of a stronger fan, not effective, since a stronger fan in a compact design, only a small gap of the housing wall with the air outlet and leaves the air intake and it can come in this small space to a pressure build-up, which preclude a rapid flow of air over the components to be cooled of the machine, especially since the small remaining gap is additionally reduced by the above-mentioned fittings again. Incidentally, a stronger fan would have a higher power consumption, which would adversely affect the efficiency of the power tool.

In the hand-held power tool according to the concept of the invention, the air guide element delimits a diffuser-like outflow space between the housing wall at the air outlet on the one hand and a downstream side of the air intake means on the other hand, in which the air flowing out of the air intake means provides a volume in all three spatial directions, which leads to the air outlet , As a result, the outflow condition at the air outlet in the housing is improved, in particular with regard to a reduction of flow losses and with regard to a pressure recovery. In addition, the air guide element can be designed such that the outflowing air emerging from the housing flows away from a user of the portable power tool and thus does not hinder him at work.

Due to the improved outflow condition, the fan device achieves an improved cooling effect while maintaining the power consumption of the air intake means. Some of the associated benefits are obvious: for example, the Lüftereinrichtung be dimensioned smaller and / or have a lower power consumption, which also leads to an improved energy balance of the entire hand tool.

The air guide element is a passive, one-piece or multi-piece physical component, which is placed in the space between the housing wall of the power tool and the generally axially arranged and usually radially Ausblasenden Luftansaugmittel and together with the housing wall and the downstream side of the air intake a streamlined, So limited diffuser-like outflow space, which leads the air flowing from the air intake and usually swirling air to the air outlet while avoiding flow losses due to friction and / or Fehlanströmungen.

Due to the orientation and shape of the air guide element so a particularly aerodynamic and effective air flow is achieved. Due to the continuous increase in area of the free cross-section approximately perpendicular to the outflow direction, it is possible to convert the kinetic energy of the air flow into usable static pressure. In addition, by virtue of its shape of the sides facing the direction of rotation of the air intake means and similar to a guide vane, the air guide element deflects the air counter to the direction of rotation of the air intake means. This also builds up static pressure and increases the volume flow.

Overall, the air guide element is also a combination of the advantages of a vaned and a bladed diffuser, which despite a technically or ergonomically induced obstruction on the housing, the air over a full revolution, so can flow continuously over 360 ° of the circumference of the air intake without the Air flow is interrupted from the air intake.

Advantageous developments of the invention can be found in the dependent claims and specify in particular advantageous ways to realize the above-described concept within the scope of the problem and with regard to further advantages.

In the context of a particularly preferred structural development, the first surface contour and the second surface contour respectively extend from the housing wall to the downstream side of the air intake means leaving a gap between the air guide element and the downstream side of the air intake. The air guide element thus preferably does not contact the air intake means on the downstream side, but approaches while leaving a gap to this and thus delimits the outflow fluidly from the remaining space between the air intake and the housing wall of the power tool. The air guide element thus approaches the air intake means, so that a fluidic limitation of the outflow space is ensured from the rest of the room. This type of fluidic demarcation is used for streamlined removal of the sucked air.

The cross-sectional area transversely, preferably perpendicular to the outflow direction of the air intake means, is continuously increased, for example, by the shape of the air-guiding element, at least in a partial area of the outflow space.

For example, the air guide element is shaped such that the cross-sectional area has a first amount in a first area adjoining the air intake means and a second amount, which is greater than the first amount, in a second area adjoining the air outlet.

Advantageously, the streamlined diffuser-like outflow space is limited by the first surface contour with respect to the outflow space forms a laterally outwardly curved course.

Advantageously, the flow-favorable diffuser-like outflow space is further limited in that the second surface contour forms a curved course with respect to the outflow space with a laterally outwardly curved part and a laterally inwardly curved part. Here, it is preferred that the second surface contour with the laterally inwardly curved graduation part extends from the housing wall in the direction of the air intake means and merges with the air intake means into the laterally outwardly curved graduation part.

The first surface contour thus assumes a concave course viewed from the discharge space and the second surface contour, in each case viewed from the outflow space, has a substantially S-shaped profile with a convex course part adjoining the housing wall and a concave running part adjoining the outflow side of the air intake means.

These courses of the first surface contour and the second surface contour realize advantageously the enlargement of the cross-sectional area already shown above increasing distance from the air intake in the direction of the outflowing air, ie in the outflow direction and thus achieve the diffuser effect.

Also, more than just two curvatures of the second surface contour may be formed to promote a frictionless air flow.

In the context of a further particularly preferred development, the air guide element has a first housing bulge and a second housing bulge which taper in each case from the housing wall to the air intake means, in particular forming an axial edge transverse to the outflow direction.

Preferably, a first side of the first housing bulge facing the outflow direction forms the first surface contour, and a side of the second housing bulge facing away from the outflow direction forms the second surface contour.

The air guide element is accordingly at least two parts in this development and preferably forms part of the housing of the power tool. The housing of the power tool accordingly has in a partial area, which surrounds the air intake means, on the one hand the air outlet and on the other the first inwardly directed housing bulge and the second inwardly directed housing bulge to limit the outflow space.

If the hand tool machine has a part proximal to the user, such as a motor part or drive part, and the user has a distal part, such as a gear part, which are connected to one another via a fastening means and between which the fan device is arranged, then it is in a further development variant preferred that the air guide element of the fan device includes the attachment means spatially at least on its side facing the air intake means. The fan device could also be positioned in a handle or elsewhere in the power tool and there spatially include fastening means with the air guide element.

This avoids that the fastening means is flown by the air intake with sucked air. Thus, there is no turbulence and impairments of the air flow, but instead the air flow element spatially enclosing the fastening means is flown.

The fastening means has, for example, a first connection, such as screwed connections. In this case, the first surface contour passes the first connection in a fastening region, preferably tangentially.

In a further particularly preferred structural development, the first housing convexity forms the first surface contour on a side facing the outflow direction and the second surface contour on a side remote from the downstream side, wherein the first surface contour and the second surface contour tangentially pass the first connection in a fastening region. The air guide element thus conceals the fastening means in such a way that it delimits a first outflow space to one side and limits a second outflow space to the other side.

Following up this idea, the air guide element in a further preferred constructive development, a third housing bulge, which tapers from the housing wall to the air intake means forming a transverse to the outflow axial edge and bounded together with the first Gehäuseauswölbung and the second Gehäuseauswölbung three outflow each side. Each of the outflow spaces leads over a number of openings distributed over the circumference of the housing to the outer environment of the housing of the power tool.

Preferably, therefore, the housing forms a multi-part volute casing in a partial area which encloses the air intake means, depending on the number of connection points between the proximal part and the distal part of the handheld power tool and the position and geometry of the openings of the air outlet and depending on the geometry of the air intake means inwardly facing housing bulges that limit a number of each diffuser-like and streamlined outflow spaces and lead the sucked air in the outflow from the air intake to the respective opening. Preferably, the transition of the inwardly curved region of the second surface contour into the outwardly curved region takes place approximately at the widest point of the respective connection, which passes tangentially over the second surface contour.

Preferably, the air guide element, for example in the form of the first, second or third housing bulge, rises above an obstruction. By obstruction is meant a housing wall part, which is usually located in the lower part of the housing and which, for structural reasons, has no opening to the outside. For a rapid flow of air, it is advantageous that such obstruction is not flowed, but air sucked in by the air intake means is conveyed past the obstruction by means of the air guide element in a streamlined manner and is guided into an outflow space with an air outlet.

The air suction means may be, for example, a radial fan, and the air guide member is a multi-piece spiral case surrounding the radial fan circumferentially with a closed wall and a radial distance of the closed wall from an axis of the radial fan along a rotational direction of the radial fan.

Appropriately, the outflow space is axially limited in one direction of an air guide wall and in the other direction of a bearing shield wall according to a preferred constructive development.

embodiments

Embodiments of the invention will now be described below with reference to the drawing. This is not necessarily to scale the embodiments, but the drawing, where appropriate for explanation, executed in a schematized and / or slightly distorted form. With regard to additions to the teachings directly recognizable from the drawing reference is made to the relevant prior art. It should be noted that various modifications and changes may be made in the form and detail of an embodiment without departing from the general idea of the invention. The disclosed in the description, in the drawing and in the claims features of the invention may be essential both individually and in any combination for the development of the invention. In addition, all combinations of at least two of the features disclosed in the description, the drawings and / or the claims fall within the scope of the invention. The general idea of the invention is not limited to the exact form or detail of the preferred embodiment shown and described below or limited to an article which would be limited in comparison to the subject matter claimed in the claims. For the given design ranges, values within the stated limits should also be disclosed as limit values and be arbitrarily usable and claimable. For simplicity, the same reference numerals are used below for identical or similar parts or parts with identical or similar function.

Fig. 1

eine aus dem Stand der Technik vorbekannte Handwerkzeugmaschine in einem Längsschnitt,

Fig.

2 eine aus dem Stand der Technik vorbekannte Handwerkzeugmaschine in einem Querschnitt,

Fig. 3 das

bevorzugte Ausführungsbeispiel einer Handwerkzeugmaschine in einem Querschnitt und

Fig. 4 das

bevorzugte Ausführungsbeispiel einer Handwerkzeugmaschine in einem Längsschnitt.

Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing. This shows in a schematic representation in:

Fig. 1

a previously known from the prior art hand tool in a longitudinal section,

FIG.

FIG. 2 is a cross-sectional view of a prior art hand-held power tool of the prior art; FIG.

Fig. 3 the

preferred embodiment of a hand tool in a cross section and

Fig. 4 the

preferred embodiment of a hand tool in a longitudinal section.

Fig. 1 shows a longitudinal section and Fig. 2 The previously known hand tool 10 has a drive unit 13, an output unit 11 and an air guide 13. The drive unit 13 and the output unit 11 are connected to each other via screw 19. Between the drive unit 13, so the electric motor, and the output unit 11, so the transmission, the power tool 10 is a radial fan 15, which is also referred to as a centrifugal fan arranged. Between the fan 15 and the housing wall is usually a gap 17. The air sucked by the fan 15 passes through this gap 17 to openings in the housing and leaves above the interior of the power tool 10. In the lower part of the housing is due to there for manufacturing reasons arranged on reason obstruction 14 no opening.

Fig. 3 shows a hand tool 100 according to the concept of the invention in a cross section and Fig. 4 the same hand tool 100 in a longitudinal section A - A '. Both figures will be referred to below.

The handheld power tool 100 with a housing wall 110 has a part 104 which is proximal to the user (not shown) and a part 102 which is distal to the user and which are connected to one another via screw connections 151, 152, 153 and 154. The proximal part 104 is usually the drive part with an electric motor and the distal part 102 of the output part with a transmission. In Fig. 4 meet these two parts at the marked by a dashed line point. The fan device 118 could also be arranged in a handle or elsewhere in the power tool.

The hand tool 100 has a fan 118, of which some components are in Fig. 4 and some components in Fig. 3 can be seen, for cooling the drive and / or output part. The fan device 118 has an air intake means 114 in the form of a radial fan wheel 120, which is arranged axially and blows out in approximately the radial direction. In the housing wall 110 of the power tool 100, there is an air outlet 116 of the fan device 118 in the form of three openings 121, 122 and 123, via which the air sucked in and blown out by the fan wheel 120 leaves the interior of the hand tool 100.

The fan device 118 further has an air guide element 130 in the form of three Gehäuseauswölbungen 131, 132 and 133, which together define three downstream Abströmräume 141, 142 and 143, via which the fan 120 sucked and blown air streamlined to the respective openings 121, 122 and 123 of the air outlet 118 is guided. The outflow spaces 141, 142 and 143 are axially further by a in Fig. 4 illustrated air guide wall 126 and a bearing shield wall 128 limited.

The three housing bulges 131, 132 and 133 each form a first surface contour 161 and a second surface contour 162, which extend from the housing wall 110 to an outflow side 124 of the fan wheel 120. In this case, the three housing bulges 131, 132, 133 each form an edge, as is clearly visible. Between the edges of the three housing bulges 131, 132 and 133 and outflow side 124 usually remains a gap which is dimensioned so that the three outflow chambers 141, 142 and 143 are each fluidically separated from each other as far as possible. The three edges each form a leading edge, which is approximately parallel to the longitudinal axis of the power tool 100 (axial edge).

The outflow direction 127 of the fan wheel 120 or the air leaving the fan wheel 120 is characterized by a large number of short arrows on the fan wheel 120. The direction of rotation of the fan wheel 120 is indicated by the curved arrow.

The first surface contour 161 is shaped such that a tangent of the first surface contour 161 at the leading edge of the first housing bulge 131 with a straight line passing through a screw center 151.1 of the first screw 151 and the leading edge forms an angle α which is approximately between 0 degrees and 45 degrees.

The first surface contour 161 has a concave profile viewed from the respective outflow space and the second surface contour 162, again viewed from the respective outflow space, a part close to the housing wall which is convex and a downstream part which is concave. The concave parts of the surface contours 161, 162 of the first housing bulge 131 and the second housing bulge 132 pass tangentially through the first screw connection 151 and the second screw connection 152, respectively. The first screw 151 and the second screw 152 are thus included by the first housing bulge and the second housing bulge 131/132, respectively, and as a result, cause no disturbance in the execution of the sucked air.

The third screw 153 and the fourth screw 154 are encompassed by the third housing bulge 133, so that these also do not obstruct the air flow. The third housing bulge 133 also rises above an obstruction 112, in which for manufacturing reasons usually no opening can be provided.

From the cross section drawing according to Fig. 3 and the longitudinal section drawing according to Fig. 4 It is clear that the three outflow chambers 141, 142 and 143 in each case from the outflow side 124 of the radial fan wheel 120, which has a height 125, increased to the housing wall 110 in all three spatial directions, whereby the outflow chambers 141, 142 and 143 each form a diffuser , which aerodynamically leads the outflowing air to the respective opening 121, 122 and 123, respectively.

Claims (15)

Powered hand tool (100), comprising a housing wall (110) and a fan device (118) with an air intake means (114) and an air outlet (116) in the housing wall (110), characterized in that - The fan device (118) has an air guide element (130) and a discharge space (141, 142, 143) between the housing wall (110) at the air outlet (116) on the one hand and an outflow side (124) of the air intake means (114) on the other side and laterally over a first surface contour (161) and a second surface contour (162) of the air guide element (130 ) is limited, wherein - The first surface contour (161) and the second surface contour (162) each extend from the housing wall (110) to the downstream side (124) of the air intake means (114) and wherein - The air guide element (131) is shaped such that a cross-sectional area (Q) of the outflow space (141, 142, 143) transversely to a discharge direction (127) of the air intake means (114) with increasing distance from the downstream side (124) in the outflow direction ( 127). Hand tool (100) according to claim 1, characterized in that the first surface contour (161) and the second surface contour (162) respectively from the housing wall (110) to the downstream side (124) of the air intake means (114) leaving a gap between the air guide element (130) and the downstream side (124) of the air intake means (114) extend. Powered hand tool (100) according to claim 1 or 2, characterized in that the air guide element (130) is shaped such that the cross-sectional area (Q) at least in a partial region of the outflow space (141, 142, 143) increases continuously. Hand tool (100) according to one of the preceding claims, characterized in that the air guide element (130) is shaped such that the cross-sectional area (Q) in a first, the air intake means (114) adjacent region has a first amount and in a second separated from the first region and adjacent to the air outlet (116) region has a second amount which is greater than the first amount. Hand tool (100) according to one of the preceding claims, characterized in that the first surface contour (161) with respect to the outflow space (141, 142, 143) forms a laterally outwardly curved course. Hand tool (100) according to any one of the preceding claims, characterized in that the second surface contour (162) with respect to the outflow space (141, 142, 143) forms a curved course with a laterally outwardly curved portion and a laterally inwardly curved portion . Hand tool (100) according to claim 6, characterized in that extending the second surface contour (162) with the laterally inwardly curved portion extending from the housing wall (110) in the direction of the air intake means (114) and the air intake means (114) in the laterally outside curved course part passes. Hand tool (100) according to one of the preceding claims, characterized in that the air guide element (130) has a first housing bulge (131) and a second housing bulge (132), each of the housing wall (110) to the air intake means (114) tapers, in particular, forming a transverse to the outflow direction (127) axial edge. Hand tool (100) according to claim 8, characterized in that one of the outflow direction (127) facing side of the first Gehäuseauswölbung (131) forms the first surface contour (161) and one of the outflow direction (127) facing away from the second housing bulge (132) the second Surface contour (162) forms. Hand tool (100) according to one of the preceding claims, comprising a user-proximal part (102) and a user-distal part (104), which are connected to one another via a fastening means, wherein between the parts (102, 104) the fan device ( 118), characterized in that the air guide element (130) spatially comprises the attachment means at least on its side facing the air intake means (114). Hand tool (100) according to claim 10, wherein the fastening means comprises a first connection, in particular screwings (151, 152, 153, 154), characterized in that the first surface contour (161) passes tangentially the first connection in a mounting region. Hand tool (100) according to claim 11, wherein the air outlet (116) in the form of a number, on the housing periphery distributed openings (121, 122, 123) is formed, characterized in that the air guide element (130) has a third housing bulge (133) which tapers from the housing wall (110) to the air intake means (114) to form an axial edge transverse to the discharge direction (127) and together with the first housing bulge (131) and the second housing bulge (132) has three outflow spaces (141, 142 , 143) bounded laterally. Hand tool (100) according to claim 12, characterized in that the third Gehäuseauswölbung (133) of the air guide element (130) via an obstruction (112) rises. Hand tool (100) according to one of the preceding claims, characterized in that - The air intake means (114) is formed as a radial fan (120) and - By means of the air guide element (130) is formed a multi-piece spiral housing. Hand tool (100) according to one of the preceding claims, characterized in that the outflow chamber (141, 142, 143) on the one hand axially of a Air guide wall (126) and on the other hand by a bearing plate wall (128) is limited.

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