EP1579961A2 - Device for dampening vibrations - Google Patents

Abstract

The vibration isolation system for a handle (1) of a hand-held machine comprises shells (4, 5) which take up respectively compressive and tensile forces, and are joined to one another by a connector elements (8). Elastic bearing elements (9, 10) bracketing a load distribution element (6) consist of cellular elastomers.

Description

The invention relates to a device for vibration insulation of a handle unit of a hand-held Machine against vibrations of a major part of the machine, with a load distribution element and with a pressure shell element and a pull-shell element, between where the load distribution element is arranged, wherein the pressure and the traction shell element are defined either on the main part of the machine or on the handle unit of the machine and the load distribution element is fixed to the other of these two parts, and wherein the load distribution element from the push and pull shell element via at least one between the pressure shell element and the Lastverteilelement arranged elastic pressure bearing part and at least one arranged between the train-shell element and the load distribution element elastic Zuglagerteil is supported in the compression and tension of the handle unit.

To the vibrations of a hand-held machine, which such vibrations causes as well as possible to isolate from a handle unit of the machine, are different Constructions have become known, which for vibration damping elastic elements, For example, springs have. On the one hand should be due to the vibration insulation the Acceleration values in the arm area of the operator can be reduced to give the operator a To work as long as possible at maximum power. On the other hand should the deformations of the elastic elements used for vibration isolation not get big so it does not negatively impact the leadership of the machine comes.

For example, constructions have become known in which the handle unit more or less punctiform from the vibration-generating body of the machine by means of Steel springs, air springs or plastic springs has been decoupled. A disadvantage of this Constructions is that the demands of the best possible vibration insulation at at the same time sufficient guidance of the machine could be fulfilled only to a limited extent and / or these designs are relatively complicated and costly.

In facilities where the vibration insulation is done by rubber blocks, as it For example, from DE 31 21 882 A1, there is also generally the disadvantage that the rubber blocks are also subjected to shear, which causes it over time easy to damage the same can come.

A device of the type mentioned is known from DE 39 13 971 A1. The load distribution element is formed in this device by a wreath, the one at the main part The machine is fixed grip holder and protrudes from this outward and radially tapering outward. The shell elements are made of sections of two Handle shells formed, which the wreath in a bell-shaped expanding area take up. Between the shell elements and the wreath is on both sides of the wreath respectively a set of elastomeric damping elements, in particular rubber. Also In this device, the previously mentioned disadvantages occur. Among other things comes it in turn to relatively strong shear stresses of the elastic elements. During the It can also lead to significant changes in the guidance accuracy of the machine due to settlements of the elastic elements come.

The object of the invention is to provide an improved device of the type mentioned, on the one hand a very good vibration isolation, on the other hand a very good Guide the machine is possible. According to the invention, this is achieved by a device with the features of claim 1.

By applied in the inventive design on the elastic bearing parts Preload these can be in the vibrationally ideal operating point of their Spring characteristic to be brought. At an increase in the on a cellular elastomer acting pressure from a low pressure reduces the stiffness of the cellular elastomers normally due to buckling of the cell structure, d. H. the Elastomer becomes softer. As the pressure increases, the stiffness increases again. According to the invention, the operating point of the elastic bearing parts in this case by the Bias can be adjusted so that there is an optimal vibration damping. It It will also possible settlements in the course of use by which the leadership the machine deteriorates, counteracted.

Furthermore, in a device according to the invention, a relatively simple and cost-effective Construction can be achieved.

In a preferred embodiment of the invention, the pressure formwork element limit and the Zugschalungselement a cavity in which the load distribution element is arranged, wherein the cavity has at least one opening, which of a connecting element for the attachment of the load distribution element is interspersed, and wherein the total area the openings of the cavity less than 30%, preferably less than 10% of the cavity make up for limiting internal surfaces. It is thereby at least largely preferably substantially complete, kassenites formed system. this has the advantage that the elastic bearing parts are protected from external influences and possible Abrasion can not penetrate to the outside. Also can as elastic bearing parts inserts be used, d. H. there is no fixed bond to the surrounding components. It can be used for the elastic bearing parts zuenzpfindliche materials, which are only subjected to pressure and are protected against cracking. By variation the rigidity of the formed as inserts elastic bearing parts, the system be tailored to the specific requirements. The different ones Stiffnesses of various existing inserts may be due to different Coloring be made easily apparent.

Due to the at least largely encapsulated execution can advantageously a very torsionally rigid connection are formed so that the stability of the device even at harsh operating conditions is ensured. For a substantially complete encapsulation only one or more openings are present in the corresponding shell element, by which one or more connecting elements for fastening the load distribution element (either on the main body or on the grip unit) with play. in principle It would also be possible and possible, the gap between the connecting element and the Seal shell element, whereby a complete encapsulation could be achieved.

Fig. 1

eine schematische Seitenansicht einer handgeführten Maschine mit einem Ausführungsbeispiel einer erfindungsgemäßen Einrichtung (Schnittlinie A-A von Fig. 3);

Fig. 2

einen Schnitt entlang der Linie B-B von Fig. 3 und

Fig. 3

eine stirnseitige Ansicht auf die Griffeinheit (Blickrichtung C in Fig. 1).

Further advantages and details of the invention are explained below with reference to the accompanying drawings. In this show:

Fig. 1

a schematic side view of a hand-held machine with an embodiment of a device according to the invention (section line AA of Fig. 3);

Fig. 2

a section along the line BB of Fig. 3 and

Fig. 3

an end view of the handle unit (viewing direction C in Fig. 1).

In the figure, a drilling machine, in particular percussion drill, is shown schematically, in connection with a device according to the invention for vibration isolation of Handle unit 1 of the machine from the main part 2 of the machine in which the vibrations or Vibrations can be used, can be used. An inventive device can be used in different types of vibration generating machinery, For example, drills, demolition equipment, Schremmhämmern etc .. In the main body 2 of in The drill shown in Fig. The drive motor (not shown) is arranged. In The handle unit 1 may have various non-vibration (or less) or vibration-sensitive ones Parts of the machine be housed, such as electrical controls.

In use, the user via the handle unit 1 is a pressure and / or tensile force applied to the main part 2 of the machine (in the axial direction of the respective tool the machine). The pressure and pulling direction 3 of the handle unit 1, in which the main pressure or tensile force is applied, is indicated in Fig. 1 and 2 each by a double arrow.

The inventive device for vibration isolation of the handle unit 1 relative to the Main part 2 comprises a pressure shell element 4 and a tension shell element 5, which is a load distribution element 6 between them. The load distribution element 6 is in the illustrated embodiment rigidly connected to the main part 2. For this example, bolt-like Connecting elements 7 may be present. In the embodiment shown, the connecting elements 7 integrally formed with the load distribution element 6 and the load distribution element 6 and the connecting elements 7 are through through holes of fastening screws 17 penetrated, which screwed into threaded holes in the main part 2 are. The connecting elements 7 could also separate from the load distribution element 6 components be. Also, the connecting elements 7 could be formed integrally with the main part 2 be and the load distribution element 6 could be screwed to the connecting elements.

The pressure-shell element 4 is in the illustrated embodiment integral with a housing part or another part of the handle unit 1 is formed. To the rigid connection of the Pressure shell element 4 with the pull-shell element 5 are connecting means 8 in shape of screws present. The pressure shell element 4 could also be considered as of the handle unit. 1 be formed separate component and be rigidly connected to this.

It would also be conceivable and possible to rigidly connect the load distribution element 6 to the handle unit 1, For example, via connecting elements analogous to those shown in the figures Connecting elements 7. The pressure and pull-shell element 4, 5 would then be rigid with the Main part 2 to connect, wherein the pressure-shell element also integrally with a housing part or another part of the main part 2 could be formed.

In any case, the pressure shell element 4 and the tension shell element 5 are separate components, which are connected to each other via connecting means 8, in particular screws.

Between the pressure shell element 4 and the load distribution element 6 is an elastic pressure bearing part 9 arranged, which on a contact surface 18 of the pressure-shell element 4 and a contact surface 11 of the load distribution element 6 is present. Between the pull-shell element 5 and the load distribution element 6, an elastic Zuglagerteil 10 is arranged, which at a Contact surface 19 of the pull-shell element 5 and a contact surface 12 of the load distribution element 6 is present. The elastic bearing parts 9, 10 are formed by a cellular elastomer, in particular of a cellular polyurethane.

When exerting a compressive force in the compression and tension direction 3 on the handle unit 1, the pressure force on the pressure-shell element 4 and the elastic pressure bearing part 9 is transferred to the load distribution element 6 and from there to the main part 2. When a tensile force is exerted on the handle unit 1 in the compression and tension direction 3, the power transmission takes place via the pull-shell element 5 and the elastic tension bearing part 10 on the load distribution element 6 and from this to the main part 2. In the illustrated embodiment, during use mainly pressure forces of the handle unit 1 to transfer to the main part 2. Accordingly, the main vibration insulation from the elastic pressure bearing part 9 to take over, which may be formed for this purpose with a lower stiffness and softer than the elastic tension bearing part 10. Also, the thickness d _{1 of} the thrust bearing part 9 may be greater than the thickness d _{2 of} the tension bearing part 10. If z. B. in a demolition tool the tool gets stuck, high tensile forces must be transmitted when tearing, including the use of a thin, rigid Zuglagerteils 10 is advantageous. The vibration isolation can play a minor role in this load case.

The elastic pressure bearing part 9 and the elastic tension bearing part 10 are each on a contact surface 11, 12 of the load distribution element 6, wherein the contact surfaces 11, 12 on opposite Side of the load distribution element 6 with respect to a through the load distribution element 6 itself extending plane 13, which is perpendicular to the compression and tension direction 3. advantageously, makes the projection of the contact surface 11 and / or 12 on the plane 13 at least a large part (i.e., more than 50%) of the total cross-sectional area of the machine in this Level, with a value of more than 80% is particularly preferred. The contact surfaces 11, 12 thus extend over the majority of the handle cross section in the region of the load distribution element 6. A tilting of the handle unit 1 relative to the main part 2 is counteracted.

The elastic pressure bearing part 9 and the elastic tension bearing part 10 surrounded in the illustrated embodiment the load distribution element 6 on all sides and lie on all sides on the one hand on Lastverteilelement 6 on the other hand on the pressure shell element 4 or pull-shell element 5 at. in principle conceivable and possible it would be, in addition to the pressure bearing part 9 and the Zuglagerteil Provide 10 more elastic bearing parts, such as elastic bearing parts, which the Lastverteilelement 6 elastically store in the direction perpendicular to the compressive and tensile direction 3, wherein in addition to the pressure-shell element 4 and the pull-shell element 5 also further shell elements could be present (for example, the side, ie in the direction of vertical seen to the compression and tension direction 3, the Lastverteilelements 6 are arranged). Prefers In this case too, the elastic bearing parts would be the load distribution element 6 overall Surrounded on all sides and on the one hand on the load distribution element 6, on the other hand on a Abut shell element.

The contact surfaces 11, 12 advantageously have a substantially perpendicular to Pressure and tension direction 3 (that is, with an angular deviation of less than +/- 10 ° to the vertical) portion, which preferably the majority of the respective contact surface 11, 12th for the elastic pressure bearing part 9 or Zuglagerteil 10 makes.

The pressure shell element 4 and the traction shell element 5 define a cavity, in FIG the load distribution element 6 is arranged. If in another embodiment, more Shell elements are present, the cavity is also limited by these. Of the Cavity has in the illustrated embodiment, four openings 14, of the connecting elements 7 are interspersed. The total passage cross-sectional area of the openings 14 of the cavity is less than 30%, preferably less than 10% of the Cavity limiting inner surfaces, which in the embodiment shown by Pressure shell element 4 and pull-shell element 5 are formed. The load distribution element 6 and the elastic bearing parts 9, 10 are thus largely (total area of the openings of the Cavity less than 30% of the cavity limiting inner surface) or im Essentially complete (total area of the openings of the cavity less than 10% of the encapsulating the cavity defining inner surfaces).

But it is preferred, as shown in the embodiment shown, that only one Pressure shell member 4 and a pull-shell element 5 are present, each having a Recess, wherein in the assembled state, the cavity for receiving of Lastverteilelements 6 and the bearing parts 9, 10 form.

The load distribution element 6 preferably tapers in at least two edge regions, with respect to a parallel to the compression and tension direction 3 aligned center plane 15, 16th opposite, towards its side edge. Through these conical or wedge-shaped tapers a centering of the handle unit 1 is achieved under pressure or tensile stress. Preferably, the load distribution element 6 has in the direction perpendicular to the compression and tension direction 3 on all sides such tapered edges. In the embodiment shown, the load distribution element 6 plate-shaped with marginally tapered edges formed.

The load distribution element 6 could also have a spatial, non-planar design, whereby an adaptation to different handle shapes is possible.

To the handle unit 1 with acting lateral forces (= forces, transverse to the compression and tension direction 3 act) with respect to the main part 2 to stabilize serves in the illustrated embodiment the small clearance between the connecting elements 7 and the pull-shell element 5. A stop for limiting a lateral displacement of the handle unit 1 opposite the main part 2 could also be formed in another way, for example by acting between the load distribution element 6 and the pressure-shell element 4 Stops (which lie for example in a recess of the elastic thrust bearing part 9 could).

The elastic pressure bearing part 9 and the elastic tension bearing part 10 may advantageously be formed of mat material, whereby a very simple production of these elastomeric parts is possible. Due to the bias, the elastic bearing parts 10, 11 adapt to the shape of the pressure and tension shell element 4, 5 at. The elastic bearing parts 9, 10 are thus plate-shaped inserts which in the relaxed state, ie before insertion or after their complete relaxation after removal, have a thickness d ₁ or d ₂ which remains constant over their extent. Preferably, only a single pressure bearing part 9 and a single tension bearing part 10 are present as elastic bearing parts.

The thicknesses d ₁ , d _{2 of} the elastic bearing parts 9, 10 are reduced by at least 5%, preferably by at least 10%, from their relaxed state by the bias in the assembled state of the unit. For example, the elastic pressure bearing part 9 can be compressed to a thickness d ₁ which is in the range between 95% and 75% of the value present in the relaxed state. This area can also apply to the elastic tension bearing part 10. In another embodiment variant, the elastic tension bearing part is formed substantially softer relative to the elastic pressure bearing part and is thereby compressed more strongly in the assembled state of the device, for example, to a thickness d ₂ in the range between 5 and 20% of the thickness in the relaxed state.

The densities of the elastic bearing parts can be within a wide range depending on the application, for example in the range between 50 and 1000 kg / m ³ .

Various further modifications of the embodiment schematically shown in the figures The invention is conceivable and possible without departing from the scope of the invention leave. For example, it is conceivable and possible, instead of foamed polyurethane to use another cellular elastomer for the elastic bearing parts. Possible and possible it would also be the elastic pressure bearing part 9 and / or the elastic tension bearing part 10 in several parts although less preferred. Such a multi-part education would be for example, for the pressure-shell element 4, the traction-shell element 5 and the load distribution element 6 conceivable and possible.

By suitable shaping of the shell elements 4, 5 and / or the Lastverteilelements 6 the bias can be locally increased, for example, by appropriate inward reaching projections or elevations in a respective shell element 4, 5. It can thereby the stiffness of the elastic storage can be varied locally.

To an inclination of the handle unit 1 relative to the main part 2 at an off-center on the Counteract connection unit acting force, the elastic pressure bearing part could 9th in the area in which lower forces occur during regular use, be provided with recesses to the pressure bearing part in this area overall softer close.

Legend to the reference numbers:

1

handle unit

2

Bulk

3

Pressure and tension direction

4

Pressure shell element

5

Train-shell element

6

Lastverteilelement

7

connecting element

8th

connecting means

9

elastic pressure bearing part

10

elastic tension bearing part

11

contact surface

12

contact surface

13

level

14

opening

15

midplane

16

midplane

17

fixing screw

18

contact surface

19

contact surface

Claims (15)

Device for vibration damping of a handle unit (1) of a hand-held machine against vibrations of a main part (2) of the machine, with a load distribution element (6) and with a pressure shell element (4) and a pull-shell element (5), between which the load distribution element ( 6) is arranged, wherein the pressure and the traction-shell element (4, 5) either on the main part (2) of the machine or on the handle unit (1) of the machine are fixed and the load distribution element (6) on the other of these two parts ( 1, 2) is fixed, and wherein the load distribution element (6) from the pressure and Zug-shell element (4, 5) via at least one between the pressure-shell element (4) and the Lastverteilelement (6) arranged elastic pressure bearing part (9) and at least one between the train-shell element (5) and the Lastverteilelement (6) arranged elastic Zuglagerteil (10) in the compression and tension direction (3) of the handle unit (1) is supported, characterized in that the pressure shell ement (4) and the pull-shell element (5) are separate components, which are interconnected via connecting means (8), and that the at least one elastic thrust bearing part (9) and the at least one elastic Zuglagerteil (10), which of a cellular Elastomer are formed between the Lastverteilelement (6) and the pressure or Zug-shell element (4, 5) are biased. Device according to claim 1, characterized in that the load distribution element (6) bearing surfaces (11, 12) for the elastic pressure and Zuglagerteil (9, 10) which at least one substantially perpendicular to the compression and tensioning direction (3) section have, preferably the majority of the contact surface (11, 12) for the elastic pressure bearing part (9) and / or Zuglagerteil (10) makes. Device according to claim 1 or claim 2, characterized in that the projection of the contact surface of the Lastverteilelements (6) for the elastic pressure bearing part (9) and / or the contact surface of the Lastverteilelements (6) for the elastic Zuglagerteil (10) to a perpendicular to the pressure - and pulling direction (3) of the handle unit (1), the load distribution element (6) passing through plane (13) makes up a large part of the total cross-sectional area of the machine in this plane, preferably more than 80% of the total cross-sectional area. Device according to one of claims 1 to 3, characterized in that at least a large part, preferably at least 80%, of the entire surface of the load distribution element (6) has a contact surface (11, 12) for the elastic pressure bearing part (9) and the elastic tension bearing part (10 ). Device according to one of claims 1 to 4, characterized in that the load distribution element (6) is elastically mounted on all sides. Device according to one of claims 1 to 5, characterized in that the load distribution element (6) in at least two edge regions, with respect to a parallel to the compression and tension direction (3) of the handle unit (1) aligned center plane (15, 16), tapered towards its side edge. Device according to one of claims 1 to 6, characterized in that the pressure-shell element (4) and the tension-shell element (5) define a cavity in which the load distribution element (6) is arranged, wherein the cavity at least one opening (14 ) penetrated by a connecting element (7) for the load distribution element (6), the total area of the openings of the cavity being less than 30%, preferably less than 10%, of the cavity defining internal surfaces of the device. Device according to one of claims 1 to 7, characterized in that the pressure-shell element (4) and the pull-shell element (5) each have a recess, which in the assembled and via the connecting means (8) interconnected state of the two elements ( 4, 5) form a cavity in which the load distribution element (6) is arranged. Device according to one of claims 1 to 8, characterized in that the elastic pressure bearing part (9) and the elastic tension bearing part (10) are formed as, preferably plate-shaped, inserts. Device according to claim 9, characterized in that the elastic pressure bearing part (9) and the elastic tension bearing part (10) in the relaxed state over their expansions have constant thicknesses (d ₁ , d ₂ ). Device according to one of claims 1 to 10, characterized in that as elastic bearing parts for the load distribution element (6) only a single pressure bearing part (9) and a single train bearing part (10) are present. Device according to one of claims 1 to 11, characterized in that the at least one elastic pressure bearing part (9) has a greater thickness (d ₁ ) and / or greater rigidity than the elastic Zuglagerteils (10). Device according to one of claims 1 to 12, characterized in that the cellular elastomer is a foamed polyurethane. Device according to one of claims 1 to 13, characterized in that the thickness (d ₁ ) of the elastic thrust bearing part (9) is reduced by the bias voltage by at least 5%, preferably by at least 10%, compared to its relaxed state. Device according to one of claims 1 to 14, characterized in that the thickness (d ₂ ) of the elastic Zuglagerteils (10) is reduced by the bias of at least 5%, preferably at least 10%, compared to its relaxed state.

Images