CN101100006A - hammer drill and/or impact hammer - Google Patents

Abstract

The invention relates to a hand-held electric tool designed as a hammer drill and/or percussion hammer, having a working spindle, an impact mechanism and a drive motor, which can be connected via a transmission and clutch device with a drive spindle The countershaft and/or is connected to a hammer mechanism drive element, wherein the transmission and clutch arrangement has a transmission with a bevel gear. The invention proposes that the transmission and clutch device ( 21 ) has only the bevel gear transmission ( 54 ) as transmission ( 20 ).

Description

hammer drill and/or impact hammer

technical field

The present invention relates to a hand-held power tool in the form of a hammer drill and/or percussion hammer, having a working spindle, a drive motor, which can be connected to an intermediate shaft and/or driving the working spindle via a drive-and-clutch device Or a percussion mechanism drive element connection, wherein the transmission and clutch device has a transmission with a bevel gear transmission.

Background technique

Hammer drills and/or percussion hammers of the weight class up to approximately 3 kg are mostly constructed in the form of pistols. This pistol design is characterized by axes arranged parallel to one another, so that the motor axis of the drive motor runs parallel to the work spindle to which a tool, for example a drill, can be coupled. The structural form of the pistol is characterized by a large structural length.

The hammer drill and/or percussion hammer of the L-design has a shorter construction length than the pistol design. The L-design is characterized in that the motor axis of the drive motor runs at an angle to the working spindle.

A known construction of an electric hand tool designed as a hammer drill and/or percussion hammer is the L-design, in which a drive motor can be connected via a transmission to an intermediate shaft. The transmission consists of a bevel gear and a spur gear connected to the bevel gear. A clutch device makes it possible to drive the transmission element of the hammer mechanism in order to operate the hammer mechanism. As soon as the clutch device also drives the working spindle via the layshaft, a combined drilling and percussion operation results. If the clutch device decouples the layshaft, only the transmission element of the impact mechanism remains coupled to the drive motor, so that a pure chisel operation results. If the drive element of the hammer mechanism is decoupled from the drive motor by means of a clutch, while the intermediate shaft is still driven, a purely drilling operation results.

The construction of known hand-held power tools is relatively complex and therefore expensive. Furthermore, such a design requires a considerable space requirement, which results in a corresponding size of the hand power tool.

Contents of the invention

In the case of an electric hand tool of the type mentioned at the outset designed according to the invention as a hammer drill and/or percussion hammer, it is provided that the drive and clutch device has only a bevel gear drive as a drive. Thus, a simple and cost-effective construction is achieved. The high quality of hand power tools is maintained. By eliminating the spur gear directly downstream of the bevel gear, fewer structural components are required and construction space is saved by eliminating the spur gear. A very compact construction can thus be achieved.

According to a refinement of the invention it is provided that the bevel gear is designed as a single stage. The bevel gearing preferably consists of only a driving bevel gear which is non-rotatably connected to the motor shaft and in particular a driven bevel gear which meshes with the driving bevel gear and is coupled with a sliding sleeve for rotary drive. Drive bevel gears, driven bevel gears and sliding sleeves belong to the transmission and clutch arrangements mentioned.

The electric hand tool according to the invention is in particular designed as an L-design, in which case a motor shaft of the drive motor extends at an angle relative to the working spindle.

In a first sliding position, the sliding sleeve is coupled for rotational drive with the hammer-mechanism drive element and is decoupled from the hammer-mechanism drive element in a second slide position. Thus, the striking mechanism is driven in the first slide position and stopped in the second slide position. Furthermore, it is preferably provided that the countershaft is axially displaceably mounted and is coupled for rotational drive to the sliding sleeve in a first sliding position and is decoupled from the sliding sleeve in a second sliding position. If the countershaft is not driven, this countershaft cannot drive the work spindle either. The assignment of the individual operating modes is preferably effected by axial displacement of the countershaft. Here too, the intermediate shaft controls the sliding position of the sliding sleeve. In total, three operating modes are possible: a) combined drilling and percussion operation, b) pure chiseling operation and c) pure drilling operation.

According to a refinement of the invention, it is provided that the axis of rotation of the driven bevel gear is centered with the axis of rotation of the intermediate shaft and/or the axis of rotation of the sliding sleeve. Thus, the two or three structural components are connected in series with concentric axes of rotation.

An axially displaceable countershaft also belongs to the mentioned transmission and clutch arrangement.

Description of drawings

The accompanying drawings illustrate the invention by means of an embodiment, showing:

Figure 1 A kind of L-structured hand power tool as a hammer drill and/or impact hammer,

Fig. 2 A longitudinal section view of an internal area of the hand power tool in Fig. 1,

Figure 3 is a longitudinal section view of an interior region of a hand power tool according to another embodiment, and

Fig. 4. Longitudinal section view of an intermediate shaft area of a hand power tool.

Detailed ways

FIG. 1 shows a hand power tool 1 which is designed as a hammer drill and/or percussion hammer 2 . The housing 3 of the hand power tool 1 is provided with a handle 4 which has an on/off switch 5 . In addition, a working mode selection switch 6 is also arranged on the housing 3 . A tool holder 7 connected to the working spindle of the hand-held power tool 1 can receive a tool 8 , for example a drill bit. A drive motor of the electric hand tool 1 is powered via a power supply lead 9 . The longitudinal extension of a motor shaft of the drive motor is marked with a dotted line 10 . The motor shaft extends at an angle, in particular at an angle of 90°, to the axis of rotation of the working spindle marked with dashed line 11 .

According to FIG. 2 , a drive motor 12 is mounted inside the housing 3 of the hand-held power tool 1 , the motor shaft 13 of which has an axis of rotation 14 . The motor shaft 13 is rotatably mounted by means of a ball bearing 15 and carries on its end 16 a driving bevel gear 17 which meshes with a driven bevel gear 18 whose axis of rotation 19 An angle of 90° is formed with respect to the above-mentioned axis of rotation 14 . The driving bevel gear 17 and the driven bevel gear 18 form a transmission 20 of a transmission and clutch arrangement 21 .

The driven bevel gear 18 is rotatably mounted by means of a ball bearing 22 and a slide bearing 23 axially downstream of the ball bearing. In addition, the driven bevel gear 18 has a formed-in axial rotary projection 24 which extends in the direction of the rotational axis 19 and is connected to the driven bevel gear 18 in a rotationally fixed manner. A sliding sleeve 25 is movably supported on the carrying projection 24 in such a way that it can be moved along the axis of rotation 19 in the direction of the double arrow 26 in FIG. in rotary drive. A helical compression spring 28 , which acts on an inner ring flange 29 of the slide sleeve 25 and presses the slide sleeve in the direction of the arrow 30 , is supported on a shoulder 27 of the drive projection 24 . Carry and turn protruding part 24 on the end 31 of sliding sleeve 25 and fit into its interior, wherein, construct a corresponding counter-shaping structure with this carrying turning shaping structure there, therefore can be on driven bevel gear 18 or its Torque transmission is realized between the rotating protrusion 24 and the sliding sleeve 25 . This torque transmission is independent of which sliding position the sliding sleeve 25 is in. An end section 33 of the intermediate shaft 34 fits into the other end 32 of the sliding sleeve 25 in such a way that a toothing 35 on the end section 33 of the intermediate shaft 34 is aligned with An internal toothing 36 of the sliding sleeve 25 engages. Furthermore, the end face 37 of the intermediate shaft 34 rests on the inner ring flange 29 .

The holding cup 38 of the housing 3 supports a ball bearing 39 which supports a hammer mechanism drive element 40 which is also supported on the intermediate shaft 34 by means of a bearing sleeve 41 . The bearing sleeve 41 is located in the region of the end section 33 . The countershaft 34 has a toothing 42 , with which an end section 43 of the countershaft 34 engages, which end section is rotatably and axially displaceably mounted in the housing 3 . The intermediate shaft 34 can be moved axially in the direction of the double arrow 26 by means of the operating mode selector switch 6 . According to FIG. 4 , a ball bearing 60 is located on the intermediate shaft 34 in addition to the toothing 42 . This ball bearing is arranged between the rotating body 52 and the toothing 42 and cooperates with a switching block 61 . The manual rotation of the working mode selection switch 6 is converted into linear motion through the eccentric connection with the conversion block 61 , so that the intermediate shaft 34 can move axially in the direction of the double arrow 26 .

A pivoting lever 44 is supported on the impact mechanism drive element 40 at an acute angle d with respect to the axis of rotation 19 by means of a ball bearing 45 , which also forms the axis of rotation for the intermediate shaft 34 , wherein the pivoting lever 44 and A piston 46 of the striking mechanism 47 is in rotational connection. The piston 46 is supported in the direction of the double arrow 26 in a hammer tube 48 of the hammer mechanism 47 (axis 49 ). Axis 49 is parallel to axis of rotation 19 . The toothing 42 of the intermediate shaft 34 meshes with a spur gear 50 arranged on the hammer tube 48 so that the hammer tube 48 can rotate about the axis 49 . The spur gear 50 is positively and non-positively connected to a positioning disc 62 . The positioning disc 62 is positively connected to the hammer tube 48 . If the working tool, such as a drill bit, is stuck, the spur gear 50 moves in the direction of the arrow 30 against the force of the spring 63 and disconnects the positioning disc 62 (pawl, cam and/or ball or the like) and The connection to the drive motor 12 is thus disconnected.

The following function is obtained: If the operating mode selector switch 6 is in a position that results in the sliding position of the intermediate shaft 34 known from FIG. 2 , the rotation of the motor shaft 13 is transmitted to the driven bevel gear 18 via the driving bevel gear 17 On, wherein the carrying protrusion 34 makes the moving sliding sleeve 39 rotate. Through the meshing of the internal tooth structure 36 and the tooth structure 35 on the intermediate shaft 34, the sliding sleeve 25 drives the intermediate shaft 34 to rotate. At this time, the rotation of the intermediate shaft 34 is transmitted to the hammer tube 48 through the tooth structure 42 and the cylindrical gear 50 and is transmitted by the There it is passed on to the work spindle of the hand power tool 1 which cannot be seen from FIG. 2 . The rotating projection 51 at the end 32 of the sliding sleeve 25 transmits the rotational movement of the sliding sleeve 25 to a rotating body 52 of the impact mechanism drive element 40 on which—in the inclined position—the Ball bearings 45 and corresponding rocker levers 44. Through the rotation of the rotor 52 , the rocker lever 44 is swiveled back and forth according to the double arrow 53 , so that the piston 46 in the hammer tube 48 is moved back and forth. As a result, the air cushion generated by the piston movement acts on a hammer which acts on a striking pin, so that the tool 8 performs a striking movement. Since the working spindle not only rotates but also performs a percussion movement, a combined drilling and percussion movement results.

If the operating mode selection switch 6 is adjusted such that the intermediate shaft 34 moves in the direction of the arrow 30, that is, it is in a new sliding position, the tooth structure 35 withdraws from the internal tooth structure 36, that is to say, between the sliding sleeve 25 and the intermediate There is no longer synchronous rotation between the shafts 34 . The result is that the working spindle is no longer driven, but nevertheless the work of the striking mechanism 47 is carried out, so that a pure chiseling operation is obtained.

The operating mode selector switch 6 can also be adjusted such that the intermediate shaft 34 is moved axially against the direction of the arrow 30 to such an extent that the sliding sleeve 25 is driven axially by means of the end face 37 via the inner ring flange 29 to such an extent. Move, cause to carry and turn protruding part 51 to withdraw from a corresponding corresponding tooth structure of rotating body 52 and therefore do not carry out the rotational driving of rotating body 52, make impact mechanism 47 stop operation thus. Nevertheless, the rotational drive between the sliding sleeve 25 and the intermediate shaft 34 remains, so that a purely drilling mode of operation results.

Thus, according to the invention, a simple operating mode changeover with an axially movable countershaft 34 takes place. Here, a very simple design structure is obtained. The construction is also characterized by tolerance independence based on the functional separation between striking mechanism 47 and transmission 20 . All parts have a good support and a compact construction is achieved. This mounting is characterized by a separate mounting of the bevel gear 54 , which is formed by the driving bevel gear 17 and the driven bevel gear 18 , and of the impact mechanism 47 . The torque transmission of the drive motor is achieved by the optimal mounting of the bevel gear 54 , but there is no transmission of the bearing force via the impact mechanism. The tolerance chain is short and the tooth play of this bevel gear 54 is small. The transmission 20 is realized directly on the axis of the intermediate shaft 34 (axis of rotation 19 ).

The embodiment in FIG. 3 differs from the embodiment in FIG. 2 only in that the driven bevel gear 18 is mounted by means of a radial/thrust bearing 55 . This results in a precise and low-play construction in which the forces from the torque transmission are directed directly to the housing 3 (transmission flange). The sliding sleeve 25 is not supported on the driving protrusion 24 of the driven bevel gear 18 , but is axially movably fitted into the driving groove 56 of the driven bevel gear 18 . In other respects, this configuration corresponds to the embodiment according to FIG. 2 , so that reference is made to the embodiment in FIG. 2 .

Thanks to the sliding sleeve 25 , axis misalignment and/or tolerance compensation between the bevel gear 54 and the countershaft 34 or the gear carrier is achieved. The bevel gears (driving bevel gear 17 and/or driven bevel gear 18 ) can be constructed in one piece or in multiple pieces. Processing of a sintered component or forming technology, respectively, is also conceivable. In the case of a multi-part construction, one spindle (Dorn) of the respective bevel gear can be mounted by means of extrusion. The sliding sleeve 25 can be realized as a shaped part or as a sintered part.

Claims (8)

1. Electric hand tools consisting of hammer drills and/or percussion hammers, having a working spindle, an impact mechanism and a drive motor which can be connected via a transmission-and-clutch device with an intermediate shaft driving the working spindle and /or connected to a percussion mechanism drive element, wherein the transmission and clutch has a transmission with a bevel gear, characterized in that the transmission and clutch (21) has only the bevel gear The transmission (54) serves as the transmission (20). 2. The electric hand tool as claimed in claim 1, characterized in that the bevel gear (54) is designed as a single stage. 3. The electric hand tool as recited in one of the preceding claims, characterized in that it has an L-shape in which a motor shaft (13) of the drive motor (12) extends at an angle relative to the working spindle. 4. The electric hand tool as claimed in claim 1, characterized in that the bevel gear (54) has a drive bevel gear (17) which is non-rotatably connected to the motor shaft (13). 5. The electric hand tool according to one of the preceding claims, characterized in that the bevel gear transmission (54) has a driven bevel gear (18) which meshes with a driving bevel gear (17) A sliding sleeve (25) is coupled for rotary drive. 6. The electric hand tool as claimed in one of the preceding claims, characterized in that the sliding sleeve (25) is coupled for rotational drive with the impact mechanism drive element (40) in a first sliding position and in a second sliding position Disconnect from the impact mechanism drive element (40). 7. The electric hand tool as claimed in one of the preceding claims, characterized in that the intermediate shaft (34) is supported axially displaceably and is coupled with the sliding sleeve (25) in a first sliding position for rotational drive and In a second sliding position it is decoupled from the sliding sleeve (25). 8. The electric hand tool according to one of the preceding claims, characterized in that the axis of rotation (19) of the driven bevel gear (18) is connected to the axis of rotation (19) of the intermediate shaft (34) and/or the sliding sleeve (25) ) of the axis of rotation (19) to the center.

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