WO2006058806A1

WO2006058806A1 - Manual machine-tool driven by circulation of a substance

Info

Publication number: WO2006058806A1
Application number: PCT/EP2005/055230
Authority: WO
Inventors: Frank Fuchs; Cristian-Aurelian Coclici
Original assignee: Robert Bosch Gmbh
Priority date: 2004-12-03
Filing date: 2005-10-13
Publication date: 2006-06-08
Also published as: EP1819482A1; CN101068658A; DE102004058581A1; US20090017738A1

Abstract

The invention concerns a manual machine-tool comprising a casing (12) and a tool (70) which is designed to be rotated and/or oscillated and which according to the invention can operate by circulation of suction air, in particular by means of an aspirator. The machine-tool is rendered particularly efficient by the presence in the form of driving system, of a turbine (36) which includes a turbine wheel (38) and has means for stabilizing incoming and exiting air, in particular a pre-directing grille (74) and/or a post directing grille, the air stream passing along the turbine wheel (38), being further circulated or deflected forming an acute angle with respect to the vertical axis (40) of the turbine wheel (38), in particular an angle less than 50°.

Description

Fluid powered hand tool machine

The invention relates to a fluid-powered hand tool according to the preamble of claim 1.

From the patent US 6347985 B 1 a hand tool is known, which is driven solely by the suction air flow of a vacuum cleaner. The core of the known power tool is a conventional Pelton turbine, the suction air of the vacuum cleaner for rotating the output spindle and thus to drive the

Tool uses.

The efficiency of the known hand-held power tools with axial and Pelton turbines, also referred to as resistance runners who deliver a mechanical power to a shaft solely due to the air pulse, can only partially meet high demands on the working and suction of operable vacuum cleaner with this handheld power tools.

Advantages of the invention

The invention with the features of claim 1 has the advantage that operated without own electric motor, only with the suction of a vacuum cleaner designed as a grinding machine hand tool for your applications has such a high efficiency that particularly much flow energy of the suction or blowing air into mechanical Performance is feasible and a virtually dust-free grinding, drilling or the like. With constant removal of dust particles forming during the grinding process is secured, so that high chip removal is combined with highly effective extraction of the grinding dust, in short, it is created a particularly advantageous variety of a turbine - Almost as a hybrid between classically flowed through radial turbine and axial turbine - which is configured as a diagonal radial turbine. It combines the advantage of low pressure loss with the advantage of increased energy yield from the air flow and therefore forms a highly effective drive for air-flowed power tools. Characterized in that the turbine upstream, fixed Vorleitgitter is arranged, which serves as a bearing seat for a rotary bearing of the axle of the turbine wheel, it assumes a supporting function of the housing structure of the power tool, so that their production costs can be kept particularly low.

The fact that the drive consists only of lightweight plastic parts, the hand tool is particularly light and handy.

The fact that the power tool is provided with a wireless switch with which the vacuum cleaner is switched on and off, is a convenient and easy operation of

Hand tool or the vacuum cleaner possible.

Characterized in that the speed control is made for the hand tool by means of a differently adjustable air damper, an adjustment of the engine speed to each existing working conditions is simple and inexpensive possible with simple means.

Due to the fact that the housing of the power tool consists of tube-like parts that can be connected to one another via flanges, it is particularly dimensionally stable and robust at a low dead weight.

drawing

Hereinafter, the present invention will be described with reference to an embodiment with accompanying drawings.

Show it:

1 shows a longitudinal section of an orbital sander

2 shows a longitudinal section of the turbine with Vorleitgitter for driving the orbital sander

FIG. 3 shows a side view of the turbine according to FIG. 2

FIG. 4 shows a side view of the turbine wheel of the turbine according to FIG. 2

FIG. 5 shows a longitudinal section of the turbine wheel according to FIG. 4

FIG. 6 shows a side view of the turbine according to FIG. 2 Figure 7 is a bottom view of the turbine wheel Figure 8 is a plan view of the Vorleitgitters

FIG. 9 a side view of the turbine wheel with inserted axle shaft FIG. 10 a spatial side view of the turbine wheel obliquely from below and FIG. 11 a spatial side view of the turbine wheel obliquely from above.

Description of the embodiment

Figure 1 shows a hand tool 10, which is designed as an orbital sander with a view of the viewer with its inside facing housing shell

14. This forms with a second, not shown, i.w. The housing 12 is assembled from the two housing shells with screws, which pass through the outer, not shown housing shell from the outside, are rotatable in Schraubdome 35 and thereby hold together the two housing shells on a butt joint .. Das Housing 12 goes on its upper side 20 in a transversely projecting from the vertical axis 13, hollow cylindrical handle 16, which serves as Saugluftaustritt 18. On its upper side 20, the housing 12 carries a louver 22, which releases or closes an opening 24 to the flow channel 26 in the interior of the housing 12 for the purpose of air inlet regulation as needed. For this purpose, a region 86 of a channel wall 28 is perforated closely adjacent to the opening 24, so that the suction air in the hose-like flow channel 26 can communicate with the outside air. The channel wall 28 is supported by support ribs 30 on the housing shells 14. The support ribs 30 are connected to reinforcing ribs 32 in the interior of the housing shell 14 and via this with the housing outer wall or the housing shell 14. As a result, the air duct 26 or the channel wall 28 is stiffened and, in particular against vibrations or resonances with the through-flowing suction air, stabilized ,

At the bottom, the housing 12 terminates in a straight peripheral bottom edge 34 which, in its vertical downward projection, forms a triangle with outwardly arched sides.

Parallel to the lower edge 34, a grinding plate 70 is arranged, which is connected via elastic oscillating body 75 to the housing 12 elastically movable. The sanding pad 70 protrudes with its ironing base on the outside beyond the triangular, vertically downwardly projected contour of the lower edge 34 and has on - A -

its underside holding means for receiving an unillustrated sanding sheet. It is orbital drivable via an axle shaft 72 and an eccentric at the end non-rotatably seated eccentric, so that each point of the sanding disc and thus each individual abrasive grain of the sanding sheet describes small circles, the typical microsection of an orbital orbital sander.

The axle shaft 72 is driven in rotation by a turbine wheel 38 of an air-driven turbine 36 and is rotatably mounted in the housing 12 or in the guide grille 74 via an upper and a lower roller bearing 64, 66 and engages with its lower end in a third roller bearing 68, with its outer ring rotatably seated in the sanding pad 70. Between the lower and the third roller bearings 66, 68, the axle shaft 72 is rotatably connected to a balancing mass 78, which serves as an unbalance compensation, to keep vibrations of the eccentrically moving sanding pad 70 from the housing 12.

The balancing mass 78 carries on its upper, the Vorleitgitter 74 side facing upwardly projecting annular profile 80. This is embraced above by an annular groove 82 with a small distance, which is arranged in the closely adjacent bottom of the Vorleitgitters 74 and 80 together with the Ringprofll a lower, labyrinth-shaped seal seal forms. This prevents dust and chips from being moved into the gap or to the lower bearing 66 as a result of the negative pressure in the cavities in the interior of the handheld power tool 10, in particular between the leveling compound 78 and the precut grid 74, so that this remains unimpaired in the long term.

The axle shaft 72 is circumferentially surrounded by the turbine wheel 38 rotatably, wherein an intimate positive connection between the two parts by knurling 73 in a defined peripheral region is made approximately in the middle of the axle shaft 72, in the wells of the casting process liquid plastic enters and thus the Connection causes.

The turbine wheel 38 has a bell-shaped outer contour, wherein the lower edge

34 axially downwardly in the housing 12 rotatably held or clamped between the housing shells 14 Vorleitgitter 74 with grid blades 75 connects. The grate blades 75 are like the paddles 42 of the turbine wheel 38 configured as standing on its narrow side plastic strip. That as a short truncated cone configured Vorleitgitter 74 is at least partially overlapped by the also in the housing 12 rotatably fixed turbine housing 60 at a distance from the height of the grate blades 75, so that thus a lower continuation of the annular flow channel 49 of the turbine wheel 38 is formed through which the suction air is drawn or passed , Via the grate blades 75, the suction air flowing in from below to drive the turbine wheel 38 in the flow direction or the flow channel 49 and the vanes 42 of the turbine 38 is directed and Entwirbelt, thereby significantly improved, in particular the input side, efficiency of the turbine 36 becomes. The Vorleitgitter 74 forms with a central recess 76 on its underside a bearing seat for a bearing 66 of the lower portion of

Axle shaft 72 which defines this in the housing 12 and leads.

Figure 2 shows a longitudinal section of the turbine wheel 38 with the axially downwardly following, fixed in the housing 12 Vorleitgitter 74 as a detail, which are shown assembled in Figure 1. It is - similar to the compact one

Citrus squeezer - a frustoconical outwardly arched cone 48 recognizable, the outside carries a plurality of paddles 42, which have the shape with its narrow side on the support cone 48 standing arranged, flat plastic strips and their height gradually increases toward the - virtual - cone point. About the paddles 42 to the support cone 48 and the upper edges of the paddles 42 approximately parallel deck cone 44 is added. As a result, an annular cross-section flow channel 49 is formed between the support and the deck cone 48, 44. This is divided by the paddles 42 into a plurality of twisted individual channels, in which the suction air can flow to drive the turbine 36 with a particularly low flow resistance. The lower edge of the support cone 48 is approximately below 45 °

Angle inclined to the cone axis and does not run as in conventional radial turbines by about 90 ° transverse to the cone axis. In a particularly favorable embodiment of the turbine 36, the inflow angle of the blade is 40 ° and its outflow angle is 30 °. A movement arrow 62 shows that the air flowing along the paddle wheel 42 is deflected by 45 °, measured to the axis 40, wherein the

Redirection across the plane is not yet considered. The deck cone 44 adjoins the top of the virtual cone tip 46 with a minimum distance to the channel wall 28 of the air channel 26, through which the suction air is streamlined out to the vacuum source or the vacuum cleaner.

The support cone 48 or truncated cone of the turbine wheel 38 is of a central

Hollow cylinder 54 penetrated to receive the axle bolt 72. The hollow cylinder 54 forms a projecting, annular collar 52 at the top in the region of a virtual cone tip. As a result, the hollow cylinder 54 reaches such a length that the axle shaft 72, with a defined axial projection and defined area of its knurling 73, secured to the turbine wheel with this knurling 73 in the interior of the Hollow cylinder 54 is positioned and is encompassed by this, so that a secure rotational lock between the turbine wheel 38 and the axle shaft 72 is achieved.

The truncated cone cone 44, which becomes increasingly concave in the direction of the virtual tip, bears on its in the lower third of its height

Outside is an annular sealing bead 56. This is provided for axial engagement in a cross-ring groove 57 which is disposed on the turbine wheel 38 facing inside of the shell-like turbine housing 60 by engaging the sealing bead 56 acts as an upper labyrinth seal 51, and pressure losses in the interior of the turbine 36th prevented and thus significantly increases their efficiency.

To operate the power tool 10 air is sucked at the Saugluftaustritt 18 and flows through the suction holes 71 in the sanding pad 70 and between the top of the sanding pad 70 and the lower edge 34 of the housing from the outside. The air drawn in from the outside passes into the annular channel 49 of the pilot grid 74 and further into that of the turbine wheel 38.

The contact of the radial turbine wheel 38 and the abrasive grate 74 with abrasive dust-laden air may result in a grinding and dusting effect which may affect the performance of the drive and its life. To counteract this, the surfaces in contact with the intake air are structured, in particular, by small, regular golf ball-like recesses, so that they have a small flow resistance with increased surface strength. The side view of the turbine 36 shown in Figure 3 of Figure 2 can be particularly clear as a detail the turbine housing 60, the rotatably supported in the housing 12 and locked to support ribs 30 and clamped the Vorleitgitter 74 and the turbine 38 tightly engages over, in particular already above explained, upper labyrinth seal 51 forms.

The detail shown in Figure 4 of the turbine wheel 38 as a detail can be seen below the forward drawn leading edge of the paddles 42 and shown in Figure 5 longitudinal section of the turbine wheel 38 according to Figure 4 illustrates once again explained the details of Figure 2.

Figure 6 shows a side view of the turbine wheel 38 with Vorleitgitter 74, wherein the grating blades 75 in their oblique course on the curved support ring 77, outside supported by the support ring 79, can be seen.

Figure 7 shows a bottom view of the turbine wheel 38, with the support ring 88, the inner support ribs 92 and outer support ribs 90 being visible and their wall thickness progressively decreasing when viewed radially from the inside out - for casting benefits.

Figure 8 shows a plan view of the Vorleitgitters 74 with a view of the inner support ring 77, the grate blades 75 with an entrance angle of 78 ° and the outer support ring 79th

Figure 9 shows a side view of the turbine wheel 38 with inserted axle shaft 72, wherein the knurling 73 is highlighted.

Figure 10 shows a spatial side view of the turbine wheel 38 without deck cone 44 obliquely from below, the course of the paddles 42 on the support cone 48 and below the support ring 88, the inner outer support ribs 90, 92 and their different wall thickness can be seen.

Figure 11 shows a spatial side view of the turbine wheel 38 obliquely from above without deck cone 44 obliquely from above, the course of the paddles 42 are particularly clearly visible on the support cone 48 .. In one embodiment, not shown, the hand tool - similar to the previous embodiments - carries their housing a wireless switch that communicates with a vacuum cleaner associated counter switch and with the switching on and off of the vacuum cleaner and thus the hand tool is conveniently and inexpensively.

The air that flows through the power tool 10 does not flow radially inwardly as in a conventional radial turbine before it is axially deflected again in the turbine 36, but flows in both the pilot and in the radial turbine at about 45 degrees to the axis of rotation (see Pictures 3 and 4). This skew flow has the advantage that the efficiency of the turbine is significantly increased since the pressure loss within the turbine 36 and the pilot grate 74 is minimized. The inflow angle of the blade is 60 ° and the outflow angle is 30 ° to keep the outflow losses as low as possible. The angles for the

Inlet areas can vary between 0 ° and 70 ° and the angles in the outlet area can vary between 10 and 60 °. The choice of angles depends on both the amount of air and the expected speed. The Vorleitgitter 74 has the task of imparting the largest possible Vordrall the air flow, and for this reason has grids 75 with an exit angle of 78 ° (Figure 8).

In order to minimize the air noise, the paddles 42 of the turbine wheel 38 on the support cone 48 are slightly forward and in contrast to the grid blades 75 pulled slightly backwards (Figure 4 and 6). This whistling between the wheel and the grating blades 42, 75 are prevented, as they sweep past each other with a distance of only 0.5 mm and effectively 'smeared'. The small distance between Vorleitgitter 74 and turbine 36 is necessary so that the turbine 36 can be ideally flowed. An additional support ring 88 between the support ribs 90 at the bottom of the support cone 48 prevents a highly fluctuating and uncontrolled idling speed of the turbine, which can assume very high values (> 20 000 U / min), as a fan effect by purely radially arranged ribs do not occur with it can. Of the

Support ring 88 and the support ribs 90 are dimensioned increasingly thin from radially inside to outside, so that during injection molding, the material quickly and with little resistance from the inside out flow and can fill all the cavities of the mold. The additional collar 52 on the inner ring of the turbine wheel 38 is necessary so that the inserted or overmoulded axle shaft 72 can be knurled in the middle. For knurled shafts, it must be ensured during manufacture that they remain as symmetrical as possible, so that incorrect insertion can not occur (FIGS. 1, 9, 10, 11). The lower

Bearing 66 is integrated for reasons of space directly into the guide rail 74 and allows a flat design of the power tool 10.

The above-mentioned individual features are assigned an inventive quality, since they contribute together to the particular advantages of the solution.

Claims

claims

1. Hand tool with a housing (12) and a rotating and / or swinging drivable arranged tool (70), which by means of a Saugluftstromes, in particular with a vacuum cleaner, is intended to operate, characterized in that as drive a turbine (36) Turbine wheel (38) is used, which is provided with means for calming the incoming or outgoing air, in particular with Vorleitgitter (74) - and / or Nachleitgitter, wherein the turbine wheel (38) flowing air stream at an acute angle to the vertical axis ( 40) of the turbine wheel (38), in particular under 50 ° continued or deflected.

2. Hand tool according to one of the preceding claims, characterized in that the turbine wheel (38) by a labyrinth seal (51) is provided, which protects the turbine (36) against pressure loss.

3. Hand tool according to one of the preceding claims, characterized in that the Vorleitgitter (74) serves as a bearing seat (76) for a bearing (66) of the axle shaft (72).

4. Hand tool according to one of the preceding claims, characterized in that it comprises a balancing mass (78), which together with structures (80, 82) of the Vorleitgitter (74) forms a labyrinth seal (84).

5. Hand tool according to one of the preceding claims, characterized in that the Vorleitgitter (74) is installed in the structure of the housing (12) that it stiffens this.

6. Hand tool according to one of claims 1 to 5, characterized in that the air for driving the turbine wheel (38) is brought radially outward on this and then sucked radially obliquely inwardly from the outer edge of the turbine wheel (38).

7. Hand tool according to one of the preceding claims, characterized in that the housing (12) carries a radio switch with which a Vacuum cleaner on or off switching counter switch is actuated and thus at the same time the hand tool is switched on or off.

8. Hand tool according to one of the preceding claims, characterized in that it is designed as a surface grinding machine, in particular as an orbital sander.