EP2038090A1

EP2038090A1 - Electric hand tool

Info

Publication number: EP2038090A1
Application number: EP07728817A
Authority: EP
Inventors: Dietmar Saur
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2006-06-27
Filing date: 2007-05-04
Publication date: 2009-03-25
Also published as: US20090308626A1; CN101479078A; DE102006029363A1; WO2008000545A1

Abstract

Electric hand tool embodied as a hammer drill and/or slide hammer, with a work spindle, a striking tool, and an electric drive motor which can be connected to an intermediate shaft driving the work spindle and/or to a striking tool drive, via a transmission and coupling device. The transmission and coupling device have a transmission, and the transmission (50) is a multi-stage spur gear mechanism (51), the gears of which are shifted by axial displacement of the intermediate shaft (15).

Description

description

Title electric hand tool

The invention relates to a trained as a drill and / or percussion hammer electric hand tool, with a work spindle, a striking mechanism and an electric drive motor, which is connectable via a gear and clutch device with a work spindle driving intermediate shaft and / or a striking mechanism drive, wherein the transmission and clutch device has a transmission.

State of the art

The field of application for drills and / or impact hammers is very diverse. The main applications are in hammer drilling (impact drilling) and chiselling (without rotary drive). Such electric hand tools are also used in the field of Bohroder impact drills or screwdrivers. The products differ depending on the main area of use. Cutting speeds for drilling concrete, wood, steel, non-ferrous metals or plastics are very different, meaning that corresponding speeds are required. When drilling rock, the working spindle speed is much smaller than when drilling wood and steel. The speed is also dependent on the cooling medium and the material of the drill bit. There are also applications where a fast working spindle speed is required, such as while stirring. The previous drilling and / or impact hammers are not particularly suitable or only limited use for the various applications shown. As drilling and / or impact hammers ever more power dense, that is compact, built These electric hand tools are also suitable in terms of their ergonomics for use in the field of drills.

Disclosure of the invention

Trained as a drill and / or percussion electric hand tool of the invention of the type mentioned should be versatile. The original field of application of such electric hand tools should be expanded and optimized for the respective work cases. For this purpose, the transmission is designed as a multi-stage spur gear whose gears are switched by axial displacement of the intermediate shaft. This design leads to a small, handy size and allows through the multi-stage spur gear setting different working spindle speeds, so that at least one speed in particular for impact drilling / drilling is available and at least one more, faster speed especially for drilling at high speed is present. By the gear change by means of axial displacement of the intermediate shaft a simple and compact design is realized, which ensures a safe function.

According to a development of the invention it is provided that the intermediate shaft at least two, different diameter having spur gears of the spur gear are assigned such that the spur gears maintain their axial position during the axial displacement of the intermediate shaft. The spur gears are thus arranged with respect to their axial arrangement fixed within the housing of the electric hand tool, and they do not leave these axial positions when the intermediate shaft is axially displaced to make a mode switch. An operating mode change is to be understood both as a working spindle speed change, and in particular also as a change from, for example, a pure drilling operation to a percussion drilling operation or a pure chisel operation. A development of the invention provides that the intermediate shaft has a driving profile, which is rotatably coupled in different axial positions of the intermediate shaft, each having a counter-driving profile of the one or the other spur gear or with none of the spur gears. Depending on the axial position of the intermediate shaft thus comes one or the other spur gear in function, which leads to different working spindle speeds. If the intermediate shaft is decoupled by its corresponding axial displacement of the spur gears, so this can be used, for example, to perform the chisel operation, in which only a beating of the tool, but not its rotation takes place.

It is also advantageous if a rotation of the intermediate shaft is provided which rotates the intermediate shaft in its corresponding axial displacement position. This is also known as the "Variolock" operating mode allows a rotationally fixed positioning of the insert tool during chiselling.Thus, the Variolockstellung serves for positioning of the insert tool.This is rotatably mounted around the hammer axis of rotation, since there is no positive connection to the drive train.In chisel mode, the insert tool through stored the Variolock rotatably.

Finally, it is advantageous if the electric hand tool is designed in pistol design, in which a drive shaft of the drive motor is arranged to extend parallel to the work spindle.

Brief description of the drawings

The drawings illustrate the invention with reference to an embodiment and shows: Figure 1 is a side view of the boring and / or

Impact hammer trained electric hand tool,

Figure 2a to e different positions of a

Mode selector switch of the electric hand tool of Figure 1,

FIG. 3 shows an inner region of the electric hand tool of FIG. 1,

Figures 4 to 7 different positions of functional groups of the electric hand tool of Figure 1 in order to bring about different modes.

Embodiment (s) of the invention

1 shows an electric hand tool 1, which is designed as a drill and / or percussion hammer 2. The electric hand tool 1 has a housing 3 with a handle 4, wherein the handle 4, an on / off switch 5 is assigned. An electric drive motor is supplied via a power cable 6 with electrical energy. On a work spindle (rotation axis 7) is a tool holder 8 for a tool, such as a drill, arranged. The mentioned electric drive motor has a drive shaft with an axis of rotation 9, wherein the axis of rotation 9 is parallel to the axis of rotation 7, so that accordingly the electric hand tool 1 is formed in pistol design.

On the housing 3 is a mode selector switch 10 with the according to Figures 2a to 2e different modes of the electric hand tool 1 can be adjusted. This is done by turning the mode selector switch 10. The figure 2a indicates a drilling operation in a second gear by the designation B2 and a drill symbol with the additional designation "2." Figure 2b indicates a drilling operation in a first gear, characterized by the designation B1 and symbolically represented by a drill symbol and the inscription "1 . ". Figure 2c indicates a position of the mode selector switch 10 in which a percussion drilling operation is performed. This is indicated by the designation SB and represented with a drill symbol and a hammer symbol. FIG. 2d identifies a Variolock operation, which is labeled VL. Finally, Figure 2e illustrates the mode selector switch 10 in a position in which there is a clean bit operation M indicated by a hammer.

FIGS. 3 to 7 show an inner region of the drilling and / or percussion hammer 2 of FIG. 1. An electric drive motor (not shown) has a motor shaft 11 on which a pinion 12 is arranged in a rotationally fixed manner. Further, the end portion 13 of the motor shaft 11 is provided with a Stirnzahnung 14. The motor shaft 11 is rotated about the axis of rotation 9 by the electric drive motor, not shown.

Below the motor shaft 11, an intermediate shaft 15 is rotatable with the rotation axis 9 parallel to the axis of rotation 16, but axially displaceable (double arrow 17) in the housing 3 of

Electric hand tool 1 stored. For the storage of one end of the intermediate shaft 15, the bearing 19 is provided. Furthermore, a ball bearing 20 supports a rotary part 21 of a striking mechanism drive 22, wherein the rotary part 21 has a sliding bearing 23 which comprises the intermediate shaft 15. An intermediate flange 24 of the housing 3 of the electric hand tool 1 has a ball bearing 25 for supporting the intermediate shaft 15. The motor shaft 11 is rotatably held in the housing 3 by means of a ball bearing 26 and axially immovable. An axle stub 27 of a spur gear 28 is mounted in a housing-side bearing 18 about the axis of rotation 16, wherein the spur gear 28 via a ball bearing 29 another spur gear 30 rotatably supported about the axis of rotation 16 and the spur gear 30 with an axial extension 31 to the sliding bearing 23rd extends. The spur gear 28 meshes with the pinion 12 and the spur gear 30 meshes with the spur gear 14 of the motor shaft eleventh

The intermediate shaft 15 has at one end 31 'a driving profile 32 which can cooperate with Gegenmitnahmeprofilen 33, 34 of the spur gear 28 and spur gear 30 - depending on the axial position of the intermediate shaft 15-, whereby the spur gear 28 or the spur gear 30, a rotational drive of the intermediate shaft 15th causes.

The intermediate shaft 15 has a smaller diameter

Bund region 35 and a larger diameter collar portion 36, wherein the arrangement is selected such that -in the longitudinal direction of the intermediate shaft 15 seen- first the driving profile 32 is provided, then the larger diameter collar portion 36 and then the smaller diameter collar portion 35 is present.

Beyond the ball bearing 25, the intermediate shaft 15, a pinion 37 which meshes with a toothed ring 38 which is rotatably mounted on a hammer tube 39 of a striking mechanism 40. The hammer tube 39 is rotatably mounted about the axis of rotation 7 and takes the tool holder 8 in rotation with.

For hammer mechanism drive 22 includes an angularly extending to the axis of rotation 16 ball bearing 41, which supports a pivot lever 42 on the rotary member 21. The pivoting lever 42 is pivotally connected to a non-illustrated piston, which is reciprocated within the hammer tube 39 during a pivoting movement of the pivoting lever 42 to produce an air cushion acting on an arranged in the hammer tube 39 striker, which in turn on a firing pin acts to striking a clamped in the tool holder 8 tool apply. The bearing 19 is an anti-rotation 43 associated with the corresponding Axialposition- the intermediate shaft 15, the pinion 37 and thus the intermediate shaft 15 rotatably locked.

The pinion 12, the spur gear 14, the spur gear 28 and the spur gear 30 form a gear 50, in particular a multi-stage spur gear 51. The gear 50 is part of a gear and clutch device 52, which further as coupling components, the driving profile 32 and the counter-driving profiles 33 and Has 34 and driving balls 44 and corresponding capture areas in the rotary member 21. On the driving balls 44 will be discussed in more detail below. The driving balls 44, together with corresponding catching areas of the rotary part 21, form a rotary driving clutch 53.

The function of the electric hand tool 1 will be explained below with reference to FIGS. 4 to 7 on the basis of five different operating modes, which can be set by means of the operating rate selection switch 10.

If the mode selector switch 10 is rotated, this leads to corresponding axial displacement of the intermediate shaft 15, wherein the power transmission path between mode selector switch 10 and intermediate shaft 15 is not shown in detail (for example gear rack-and-pinion principle). If the intermediate shaft 15 is in the position according to FIG. 3, the driving profile 32 and counter-driving profile 33 of the spur gear 28 are coupled. The spur gear 30 is not rotatably connected to the intermediate shaft 15. The result is that rotate by rotation of the motor shaft 11 due to the operation of the drive motor, both the pinion 12 and the spur gear 14 and consequently the two spur gears 28 and 30 are taken with different speeds due to their different sizes diameter, but the spur gear 30th only rotated on the intermediate shaft 15, however no rotational drive performs, but the spur gear 28, the intermediate shaft 15 with a correspondingly fast gear, so a correspondingly large speed rotates. Mitnahmekugeln 44, which store in the corresponding recesses of the axial extension 31 of the spur gear 30, are in the smaller diameter collar portion 35 of the intermediate shaft 15 and therefore exert on catching areas of the rotary member 21 no entrainment, so that the percussion drive 22 is not in operation. The driving balls 44 form with the catching areas the rotary driving clutch 53. The intermediate shaft 15, which rotates at a corresponding rotational speed, drives the hammer tube 39 with it via the pinion 37 and the toothed ring 38 in order to mount the tool holder 8. There is therefore a drilling operation with fast speed.

If an axial position of the intermediate shaft 15 according to FIG. 4 is brought about by means of the mode selector switch 10, then the carrier profile 32 of the intermediate shaft 15 leaves the counter-driving profile 33 of the spur gear 28 and enters the counter-driving profile 34 of the spur gear 30. The result is that the drive motor upon rotation of the motor shaft 11 transmits a torque via the Stirnzahnung 14 and the spur gear 30 and thus to the intermediate shaft 15, wherein due to a larger diameter of the spur gear 30 relative to the spur gear 28, a lower speed of the intermediate shaft 15 is present. The spur gear 28 is indeed rotated by the motor shaft 15 via the pinion 12, but this does not lead to a drive of the intermediate shaft 15 due to the above-mentioned decoupling. A further difference from the state according to FIG. 3 does not arise, so that correspondingly there is a drive (pure drill drive) of the tool holder 8 with a slower gear, that is to say at a lower rotational speed.

If the intermediate shaft 15 is displaced further axially in the direction of the arrow 45 by means of the mode selector switch 10, then the situation according to FIG. 5 is present. This corresponds to one Impact drilling with a speed as it has been set in the figure 4. The speed is maintained due to the coupling of the motor shaft 11 via the spur gear 30, but the larger diameter collar portion 36 pushes the driving balls 44 to the outside, so that they occur in Mitnahmehintergriff to a corresponding formation of the rotary member 21, that is, the intermediate shaft 15 drives the rotary member 21, whereby the pivot lever 42 is placed in a double arrow 46 marked reciprocation. As a result, the piston located in the hammer tube 39 is reciprocated, the one

Creates air cushion, which acts on the striker and thus on the tool, whereby the tool performs a striking movement. It is rotated at the same time, since the hammer tube 39 is placed on the pinion 37 and the toothed ring 38 in rotary motion.

If the intermediate shaft 15 is moved further in the direction of the arrow 45 by means of the operating mode selector switch 10, the situation according to FIG. 6 arises in the so-called Variolock operation, which makes it possible to position the hammer tube 39 and thus the tool used there during chiseling. The intermediate shaft 15 is positioned axially such that a rotational drive with the spur gear 30 is no longer present, but due to the radially outwardly urged driving balls 44 of the percussion drive 22 is still coupled to the intermediate shaft 15, the pinion 37, however, not yet engaged with the rotation 43 stands. The user can now set the angular position of the insert tool itself. This occurs when the drive motor is switched off. A manual rotation of the insert tool leads to a corresponding rotation of the hammer tube 39 and via the toothed ring 38 and the pinion 37 to a rotation of the intermediate shaft 15th

If, subsequently, according to FIG. 7, the intermediate shaft 15 is displaced even further in the direction of the arrow 45 by corresponding actuation of the mode selector switch 10, the teeth of the pinion 37 end up in corresponding housing-side receptacles the rotation 43, whereby the intermediate shaft 15 is secured against rotation. This leaves the insert tool in the desired rotational position. Now, if the drive motor is put into operation, the motor shaft 11 rotates via the spur gear 14, the spur gear 30 and thus its axial extension 31, which rotates about the driving balls 44, the rotary member 21 and thus the percussion drive 22 comes into operation, that is, the Schlagwerk 40 works. Since the intermediate shaft 15 is rotationally coupled by the two spur gears 28 and 30, no rotational movement of the tool is performed, so that a pure chisel operation is present.

Claims

claims

1. As a drilling and / or percussion hammer trained electric hand tool, with a work spindle, a percussion and an electric drive motor, which is connectable via a gear and clutch device with a work spindle driving intermediate shaft and / or a percussion drive, wherein the transmission and clutch device a transmission has, characterized in that the transmission (50) is a multi-stage spur gear (51) whose gears are connected by axial displacement of the intermediate shaft (15).

2. Electric hand tool according to claim 1, characterized in that the intermediate shaft (15) at least two different diameter having spur gears (28,30) of the spur gear (51) are assigned such that the spur gears (28,30) their axial position during axial displacement the intermediate shaft (15) maintained.

3. Electric hand tool according to one of the preceding claims, characterized in that the intermediate shaft (15) has a driving profile (32) which in different axial positions of the intermediate shaft (15) each having a counter-driving profile (33,34) of the one or the other spur gear ( 28,30) or with none of the spur gears (28,30) rotatably coupled.

4. Electric hand tool according to one of the preceding claims, characterized by a rotary driving coupling (53) of intermediate shaft (15) and percussion drive (22), which performs a coupling or disengagement in dependence of the axial position of the intermediate shaft (15).

5. Electric hand tool according to one of the preceding claims, characterized by a rotation (43) of the Intermediate shaft (15) which rotates the intermediate shaft (15) in a corresponding axial displacement position.

6. Electric hand tool according to one of the preceding claims, characterized by, the training in pistol design, in which a drive shaft of the drive motor is arranged to extend parallel to the work spindle.