WO2012055670A1

WO2012055670A1 - Replaceable tool for an electric machine tool and electric machine tool comprising a replaceable tool

Info

Publication number: WO2012055670A1
Application number: PCT/EP2011/067099
Authority: WO
Inventors: Jochen Schlemmer; Matthias Kuntz; Hagen Kuckert; Max Seitter
Original assignee: Robert Bosch Gmbh
Priority date: 2010-10-29
Filing date: 2011-09-30
Publication date: 2012-05-03
Also published as: DE102010043143A1; EP2632667A1

Abstract

The invention relates to a replaceable tool (10) for an electric machine tool (100), which effects a high-frequency working motion of the tool (10), comprising a tool body (12) having a first end (14), which is designed for coupling to the electric machine tool (100), and a second end (16), which is designed for receiving a functional element (20), wherein the tool body (12) is designed at least as a longitudinal section (18) of a coupling element (150) provided for transmitting the high-frequency vibrations to at least the functional element (20).

Description

Description title

Interchangeable tool for a power tool and

Power tool with a replaceable tool

State of the art

The invention relates to a replaceable tool for a

Electric power tool and power tool with one

interchangeable tool.

Known ultrasonic powered hand held power tools include interchangeable tools, such as cutting blades, which are mounted in a receptacle on the power tool. Such a power tool machine is known, for example, from JP-A-2000-326291. The thin cutting blade is inserted between two jaws forming the receptacle and clamped by tightening a screw. If the cutting blade is exposed to vibrations, it may loosen in the worst case and worsen the result.

Disclosure of the invention

It is proposed a replaceable tool for a

Electric machine tool, which causes a high-frequency working movement of the tool, comprising a tool body having a first end, which is designed for coupling to the power tool and a second end, which is designed to receive a functional element, wherein the tool body is formed at least as a longitudinal portion of a coupling element, which is provided for transmitting the high-frequency vibrations to at least the functional element. The replaceable tool can form part of the coupling element or also comprise the entire coupling element. Advantageously, a stable and handy tool for an ultrasonic power tool can be created. A handling with fragile and sharp-edged parts at

Replacement of the tool can be avoided because the tool is sufficiently grippy and does not need to be held to the functional element to replace it. The function and the reliability can be improved by omission or reduction of unfavorable

Strength properties due to high local mechanical stresses on

Notches that can lead to breakage of the functional element, risk of fretting or poor vibration coupling. Lifetime and behavior of the tool are improved. According to an advantageous embodiment, the longitudinal section may be formed as a sonotrode or part of a sonotrode. Sonotrodes are elements which are set into resonant vibrations by the introduction of high-frequency mechanical vibrations, in particular ultrasound. You put in

Case of application, the connection of the drive unit, about one

Ultrasonic generator, to the workpiece forth and adjust the ultrasonic vibration by impedance matching to the machining task. A sonotrode is usually designed so that its resonant frequency coincides with the frequency provided by the generator provided. The amplitude or amplitude of the sonotrode at its working surface is affected by the output amplitude provided by the converter (transformation piece) and the respective gain by the booster and sonotrode itself.

The sonotrode interacts with a booster in terms of the required amplitude. The booster in ultrasonic tools, on the one hand, has the function required by the converter, i. the drive unit to change provided amplitude and forward them into the sonotrode. Booster and sonotrode can be combined in one component. According to the invention, at least a part of the sonotrode is detachably connected to the remaining component and carries a functional element, such as a drill or a blade tool. One

Blade tool may in particular be a cutting tool with one or more blades, a scraping tool or a polishing tool. According to a further advantageous development of the tool body may have a coupling for the supply of high-frequency vibrations. Thus, the tool body can be securely coupled to the power tool, such as a screw or a clamp connection. This can be made very robust, since the tool body provides a sufficient volume to perform a stable attachment.

According to a further advantageous development of the tool body may have a coupling for the supply of high-frequency vibrations. Advantageously, the coupling can be a screw connection or a clamping connection between the tool body and a contact element of

Enable power tool.

According to a further advantageous development, the functional element may be firmly connected to the tool body, in particular to the

Tool body shed or glued. This can be beneficial

Functional element in terms of its material properties on the

Machining task as cutting or drilling to be optimized, while the tool body can be designed for the vibration transmission to the functional element.

According to a further advantageous development of the tool body can be made of light metal die-cast, in particular of an aluminum die-cast.

According to a further advantageous development, the functional element may be made of a metallic or non-metallic tool material, for example of a high-speed steel. The term high speed steel, also known by the abbreviation HSS or HS according to standard EN ISO 4957, denotes a group of steel alloys having a carbon content of up to about 2% and alloying element contents of up to 30%, such as tungsten, molybdenum, vanadium, cobalt, nickel, Titanium, which forms carbides with the carbon, which have a very high hardness. As a tool material, of course, another material with suitably high hardness can be used, such as a hard metal, such as a carbide or a nitride, or a Ceramic material. Ceramics are characterized not only by their high hardness but also by their relatively low weight and high temperature resistance.

Due to the fixed connection of the functional element, for example

High speed steel, carbide or ceramic, and the tool body

Alloy metal can be provided a cheap stable tool. The functional element can be cast into the tool body, which can form a sonotrode or a part thereof. When changing tools, the complete component is made of e.g. Sonotrode and functional element replaced. Any additional costs per tool are negligible especially in the case of high quantities and due to the simple connection between functional element and tool body.

It is according to another aspect of the invention a

Power tool proposed with a replaceable

Tool, as described above, wherein the replaceable tool can be acted upon with ultrasound for at least one working movement. According to a further advantageous embodiment, the

Power tool especially a hand-held

Power tool in which all components can be combined in a single housing. Of course, the replaceable tool can also be used in a power tool that can be supplied with a separate generator. The tool can be connected to a

Coupling element be connected, which is provided for excitation transmission from an ultrasonic providing drive unit to the tool.

The electric machine tool may comprise a housing with a grip area and an actuating unit for activating the power tool and / or a working movement, a drive unit arranged in the housing for generating ultrasound, an electronics unit arranged in the housing for charging the drive unit with at least control and / or regulating signals, and a coupling element between the drive unit and the tool. The proposed power tool may be a handy one-piece device, in which disturbing connection cable between separate

Housing parts can be dispensed with. The power tool can be operated in particular cordless with batteries or rechargeable batteries.

Optionally, it may be - additionally or alternatively - operable or rechargeable with mains power via a mains cable.

Conveniently, at least the drive unit, the electronics unit and the operating voltage unit can be distributed in the housing such that a

The center of gravity of the power tool lies near the grip area. The handling of the power tool is facilitated, the

Work result can be better controlled.

Particularly compact, the power tool can be performed when the electronics unit is concentrated on a circuit board. Is that lying

Operating frequency of the actuator in the range between 10 kHz and 1000 kHz, preferably between 30 kHz and 50 kHz, in particular between 35 kHz and 45 kHz, the space required for the actuator can be reduced. It can be a favorable ratio of power and volume (and thus weight) can be achieved.

It is conceivable that the drive unit comprise at least one further drive component in addition to the at least one actuator. Advantageously, the working movement of a tool driven by the at least one further drive component can be superimposed by a movement generated by the at least one actuator, whereby the work progress can be significantly improved and the machining can be facilitated.

drawing

Further advantages emerge from the following description of the drawing. In the drawings, embodiments of the invention are shown. The drawings, the description and the claims contain numerous features

Combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations. They show by way of example:

1 shows a longitudinal section through a favorable embodiment of a

replaceable tool according to the invention;

Fig. 2 shows a first embodiment of a hand-held

Electric power tool having an elongated housing with a replaceable tool; and

Fig. 3 shows another embodiment of a hand-held

Electric machine tool with a T-shaped housing with a replaceable blade tool.

Embodiments of the invention

In the figures, the same or similar components are the same

Numbered.

Fig. 1 shows a longitudinal section through a favorable embodiment of a replaceable tool 10 for a power tool according to the

Invention. The replaceable tool 10 is designed to perform at least one working movement by means of a high-frequency oscillation, in particular in the ultrasonic range. The replaceable tool 10 has a tool body 12 with a first end 14 and a second end 16 and is detachable with the

Power tool connectable. For this purpose, a coupling 24 is provided at the first end 14 of the tool body 12, for example a

Screw thread or the like, with which the tool body 12 can be connected to a corresponding counterpart.

The second end 16 is designed to receive a functional element 20, which is fixedly connected to the tool body 12, in particular cast or glued. The tool body 12 is as a longitudinal portion 18 of a coupling element

(Coupling element 150 in FIG. 2 and FIG. 3), which is provided for transmitting the high-frequency vibrations to the functional element 20. The longitudinal section 18 is designed as a sonotrode or part of a sonotrode and typically has a catenoid shape, which tapers from the first end 14 to the functional element 20. The sonotrode can be manufactured as a component with a booster, wherein the coupling 24 is then formed to be connected to an ultrasonic actuator. If the sonotrode and the booster are separate components, the sonotrode can be designed in such a way that it can be connected to the booster arranged on the power tool machine side.

Conveniently, the tool body 12 of the interchangeable tool 10 is made of light metal die-cast, for example, aluminum or titanium, while the functional element 20 is made of steel.

In the illustrated embodiment, the tool 10 is formed elongated and the functional element 20 of the tool 10 in the

Longitudinal axis arranged. Of course, the tool 10 may be formed at an angle and / or the functional element 20 may also be arranged transversely to the longitudinal axis.

To further explain the invention, FIGS. 2 and 3 show various examples of hand-held electric machine tools 100

replaceable tool 10. Fig. 2 shows a hand-held

Electric machine tool 100 with elongated housing shape; Fig. 3 shows a hand-held power tool 100 with a T-shaped housing.

The power tool 100 may in particular be designed as a hand-held power tool 100, in which all components are arranged in a single housing 102. In particular, the

Power tool 100 power-free with a battery pack 110 are operated. The hand-held power tool 100 includes a housing 102 having a grip portion 104. An operator stops the power tool 100 the grip portion 104 or includes the handle portion 104 by hand and can safely guide the power tool 100, without by a

Cable connection to a generator to be disturbed. The grip area 104 may optionally be decoupled with a damping element, not shown, with respect to other housing areas.

A housing-side operating part 130 serves for the user-side activation of the tool 10 and / or of the electric machine tool 100. The operating part 130 may e.g. may be a switch or a regulator or may also comprise a plurality of operating elements 130, 122, of which e.g. one to turn on

Power tool 100 and one for turning on and / or controlling the tool 10 may be provided.

In the housing 102, a drive unit 140 is arranged, which in the examples according to FIG. 2 and FIG. 3 comprises only one drive component, which by a

Actuator is formed. This may be formed as a piezo-excited Langevin oscillator (also called a piezoactuator) comprising a volume of piezoelectrically active material 144, e.g. Piezoceramic discs in one

Stacking direction are stacked and pressed together and perform a change in length when exposed to electrical voltage.

When exposed to high-frequency electrical voltage ultrasound is generated in a conventional manner, which is passed via a coupling element 150 to the tool 10.

The coupling element 150 may be a per se known sonotrode. The length and the shape as well as the material of the coupling element 150 determine a resonant frequency of the actuator. Also, the tool 10, the

Affect resonant frequency. In the embodiment variants in FIGS. 2 and 3, the actuator is designed such that Langevin oscillators 144 and coupling element 150 are combined in one unit, and their entire length corresponds to approximately half the wavelength λ / 2 of the ultrasonic oscillation. Other embodiments may provide that the actuator is composed of several components with the length λ / 2. These can be:

Vibration generator, known as a converter, in particular, for example, a Langevin- oscillator 144, amplitude transformation pieces, known as boosters, possibly extension pieces, and the coupling element known as sonotrode. The replaceable tool 10 can be acted upon by ultrasound for at least one working movement. The tool body 12 is at least part of the sonotrode, in particular, the tool body 12 forms the sonotrode.

Optionally, the booster can be integrated into the sonotrode.

The trained as a sonotrode tool body 12 is detachably coupled to a coupling piece 152 and connected to the Langevin oscillator 144, so that an excitation transfer from the ultrasound providing drive unit 140 can be done on the tool 10.

An electronics unit 120 arranged in the housing 102 serves for

Actuation of the drive unit 140 with at least control and / or

Control signals, as well as the power supply of the actuator or the Langevin- vibrator 144 of the actuator. The electronics unit 120 can be accommodated on a single board in a space-saving manner (FIG. 2) or at e.g. be distributed two boards (Fig. 3), wherein one in the main part and in a transversely projecting from the main part of the handle portion of the T-shaped housing 102 is arranged. Drive unit 140, electronic unit 120 and operating voltage unit or battery pack 110 are advantageously distributed in housing 102 such that a center of mass in

Area of the handle portion 104 is located.

The operating voltage unit 110, here designed as a battery or accumulator pack with batteries or rechargeable batteries, serves to provide a direct electrical voltage for the electronics unit 120, which the

Operating voltage in a high-frequency voltage signal converts, with which the actuator is excited in the desired manner to oscillate.

The electronic unit 120 is in particular designed to operate the at least one actuator in a resonant frequency f_res. It includes the

Electronic unit 120, a control unit for tracking the resonance frequency f_res of the actuator. The control unit may comprise a phase locked loop, which can excite the actuator in the resonant frequency, wherein a

Phase shift between the injected current and the supplied voltage is set to 0 °. Preferably, the resonance frequency f_res is readjusted when due to heating or load changes on Tool changes the resonant frequency. Alternatively, a frequency tracking can be done by regulating to a maximum of the current fed into the actuator.

Claims

claims

An interchangeable tool (10) for a power tool (100) causing a high frequency working movement of the tool (10) characterized by a tool body (12) having a first end (14) adapted for coupling to the power tool (100) is and a second end (16), which is to receive a

Functional element (20) is formed, wherein the tool body (12) is formed at least as a longitudinal portion (18) of a coupling element (150) which is provided for transmitting the high-frequency vibrations to at least the functional element (20).

2. Interchangeable tool according to claim 1, characterized in that the longitudinal section (18) is designed as a sonotrode or part of a sonotrode.

3. Interchangeable tool according to claim 1 or 2, characterized

in that the tool body (12) has a coupling (24) for supplying high-frequency vibrations.

4. Interchangeable tool according to one of the preceding claims, characterized in that the functional element (20) is fixedly connected to the tool body (12).

5. Interchangeable tool according to claim 4, characterized in that the functional element (20) with the tool body (12) is cast.

6. Interchangeable tool according to claim 4, characterized in that the functional element (20) with the tool body (12) is glued.

7. Interchangeable tool according to one of the preceding claims, characterized in that the tool body (12) is made of light metal die-cast.

8. Interchangeable tool according to one of the preceding claims, characterized in that the functional element (20) is made of a metallic or non-metallic tool material.

9. Electric power tool (100), in particular a hand-held

Electric machine tool, with a replaceable tool (10) according to one of the preceding claims, wherein the interchangeable

Tool (10) can be acted upon with ultrasound for at least one working movement.

10. Power tool according to claim 9, wherein the tool (10) to a coupling element (150) can be connected, which for the excitation transmission from an ultrasonic providing drive unit (140) on the

Tool (10) is provided.