Handheld power tool with a locking mechanism

Abstract

The invention relates to a hand-held power tool, in particular an impact drill, having a housing in which a drive unit for driving a driven main shaft (120) is arranged, wherein the drive unit is equipped with a locking mechanism (130) which has a first crown disk (222) torsionally connected to the driven main shaft (120) and a second crown disk (220) torsionally arranged in the housing (105), and wherein, in a first position, the first and second crown disks (222, 220) are in contact with one another via assigned locking geometries (291, 292), and in a second position, the second crown disk (220) is arranged spaced apart from the first crown disk (220) along the rotational axis (109) of the driven main shaft (120), and an annular friction element (230) is provided which is arranged frictionlessly in the first position and generates a predefined frictional force between the first and second crown disks (222, 220) in the second position.

Description

Technical Field

[0001] The present invention relates to a hand-held power tool, in particular an impact drill, having a housing in which a drive unit for driving a driven main shaft is arranged, wherein the drive unit is equipped with a locking mechanism which has a first crown disk torsionally connected to the driven main shaft and a second crown disk torsionally arranged in the housing, and wherein, in a first position, the first and second crown disks are in contact with each other by means of an assigned locking geometry, and in a second position, the second crown disk is arranged spaced apart from the first crown disk along the rotational axis of the driven main shaft. Background Art

[0002] This type of hand-held power tool configured as an impact drill is known from the prior art. The hand-held power tool has a drive unit which has a locking mechanism. The locking mechanism has a first and a second crown disk, wherein the first crown disk is torsionally arranged with respect to the driven main shaft of the drive unit, and wherein the second crown disk is torsionally arranged in the housing of the hand-held power tool. During drilling operation or when the locking mechanism is activated, the two crown disks are in contact with each other for a short time, while when the locking mechanism is deactivated, the two crown disks are arranged spaced apart from each other along the rotational axis of the driven main shaft. Summary of the Invention

[0003] The present invention relates to a hand-held power tool, in particular an impact drill, having a housing in which a drive unit for driving a driven main shaft is arranged, wherein the drive unit is equipped with a locking mechanism which has a first crown disk torsionally connected to the driven main shaft and a second crown disk torsionally arranged in the housing, and wherein, in a first position, the first and second crown disks are in contact with each other by means of an assigned locking geometry, and in a second position, the second crown disk is arranged spaced apart from the first crown disk along the rotational axis of the driven main shaft. An annular friction element is provided which is arranged without friction in the first position and generates a pre-defined frictional force between the first and second crown disks in the second position.

[0004] Accordingly, the present invention is able to provide a hand-held power tool with a locking mechanism in which a frictional force is safely and reliably generated only in the second position by means of the friction element. Thereby, the service life of the friction element can be significantly increased.

[0005] Preferably, the first crown disk has an outer circumferential groove at its end facing the drive unit for arranging the annular friction element.

[0006] Accordingly, a suitable arrangement of the friction element can be achieved in a simple manner.

[0007] According to another embodiment, the second crown disk has a circumferential groove on its inner circumference for arranging the annular friction element.

[0008] Therefore, an alternatively suitable arrangement of the friction element can be achieved in an easy and uncomplicated manner.

[0009] Preferably, the first crown disk has a circumferential ring on its outer circumference, which is configured perpendicular to the rotational axis of the driven main shaft, wherein the annular friction element abuts against the circumferential ring in the second position.

[0010] Therefore, an increase in the frictional force generated by the friction element in the second position can be achieved safely and reliably.

[0011] According to another embodiment, the driven main shaft has a circumferential groove on its outer circumference for receiving the annular friction element.

[0012] Therefore, another suitable arrangement of the friction element can be achieved in a simple manner.

[0013] Preferably, the annular friction element is an O-ring.

[0014] Therefore, a robust and stable friction element can be provided.

[0015] Preferably, the annular friction element has rubber and / or felt.

[0016] Therefore, a simple and cost-effective friction element can be provided.

[0017] Preferably, the drive unit includes a main shaft locking device, wherein the annular friction element prevents the triggering of the main shaft locking device in the second position.

[0018] Therefore, a safe and reliable operation of the main shaft locking device can be achieved, since the inadvertent activation of the main shaft locking device can be prevented by the friction element.

[0019] Preferably, the first and second crown disks are arranged in the second position during the drilling and / or screwing operation of the hand-held power tool.

[0020] Therefore, during the drilling and / or screwing operation, the frictional force can be generated simply and uncomplicatedly by the friction element.

[0021] According to one embodiment, the drive unit has a planetary gear transmission.

[0022] Therefore, a suitable transmission can be provided in a simple manner. Description of the Drawings

[0023] In the following description, the invention will be explained in more detail based on the embodiments shown in the drawings. The drawings show:

[0024] Figure 1 : A schematic front view of an exemplary hand-held power tool having a drive unit,

[0025] Figure 2 : Figure 1 Longitudinal section of a drive unit having a latching mechanism and a friction element,

[0026] Figure 3 : Figure 2 Front view of an enlarged area of in which the friction element is arranged in a passive first position;

[0027] Figure 4 : Figure 3 Front view of an enlarged area of in which the friction element is arranged in an activated second position;

[0028] Figure 5 : Figure 4 Front view of an enlarged area of having an alternative arrangement of the friction element, in which the friction element is arranged in a passive first position, and

[0029] Figure 6 : Figure 4 Front view of an enlarged area of having another alternative arrangement of the friction element, in which the friction element is arranged in a passive first position.

[0030] In the drawings, elements having the same or similar functions are provided with the same reference numerals and are described in detail only once. Detailed Description

[0031] Figure 1 An exemplary hand-held power tool 100 is shown, which preferably has a housing or machine housing 105 with a handle 115. According to one embodiment, the hand-held power tool 100 can be mechanically and electrically connected to a battery pack 190 in order to be independent of the mains power supply.

[0032] The hand-held power tool 100 has a drive unit 107 for driving a driven main shaft 120, which rotates about a rotational axis 109 during operation. Here, the hand-held power tool 100 is equipped with at least one drive motor 180 and a latching mechanism 130. Illustratively, the hand-held power tool 100 has an optional torque clutch 160, but can also be constructed without a torque clutch 160.

[0033] In Figure 1 the hand-held power tool 100 is, for example, constructed as a battery-powered impact drill. However, it should be noted that the present invention is not limited to battery-powered impact drills, but can be applied to different hand-held power tools that have a latching mechanism 130, regardless of whether the hand-held power tool can be electrically operated, i.e., operated with a battery pack 190 independently of the mains power supply or operated depending on the mains power supply and / or can be non-electrically operated.

[0034] Preferably, the drive unit 107 is arranged in the housing 105. According to one embodiment, the drive unit 107 is equipped with a transmission 170, which is preferably configured as a planetary gear transmission. Preferably, the transmission 170 is a planetary gear transmission configured with different gears or planetary stages, which is rotationally driven by the drive motor 180 during the operation of the hand-held power tool 100. Here, for example, an electric drive motor 180 powered by a battery pack 190, the transmission 170 and / or the locking mechanism 130 are arranged in the housing 105. The drive motor 180 is preferably connected to the driven spindle 120 via the transmission 170. The drive motor 180 is illustratively arranged in the motor housing 185 and the transmission 170 is arranged in the transmission housing 110, wherein the transmission housing 110 and the motor housing 185 are, for example, arranged in the housing 105. Preferably, the transmission 170 is equipped with the locking mechanism 130. In particular, the transmission 170 is thereby equipped with an impact function.

[0035] Preferably, the transmission 170 is configured to transfer the torque generated by the drive motor 180 to the driven spindle 120. The drive motor 180 can be, for example, operated by a manual switch 195, i.e., can be turned on and off, and can be of any motor type, such as an electronically commutated motor or a DC motor. Preferably, the drive motor 180 can be electronically controlled or adjusted such that not only reverse operation but also a pre-given operation with respect to the desired rotational speed can be achieved. The operating mode and structure of suitable drive motors are well known from the prior art, such that a detailed description is omitted here for the sake of brevity of the specification.

[0036] Preferably, the driven spindle 120 is rotatably supported in the housing 105 by a bearing assembly and is connected to the tool receiving portion 145, which is arranged in the region of the end side 112 of the housing 105 and is configured, for example, in the type of a drill chuck. The tool receiving portion 145 is used to receive the insert tool 150 and can be formed on the driven spindle 120 or connected to the driven spindle in an accessory-like manner.

[0037] Illustratively, the driven spindle 120 is equipped with a spindle locking device 250. The spindle locking device is arranged, for example, in the axial direction of the driven spindle 120 or along the rotational axis 109 of the driven spindle 120 between the transmission 170 and the tool receiving portion 145 and is used to fix the driven spindle 120 when the drive motor 180 is turned off. The function of the spindle locking device 250 is well known from the prior art, such that a detailed description of the function of the spindle locking device 250 is omitted here for the sake of brevity of the specification.

[0038] Figure 2 Shown Figure 1The transmission device 170, the main shaft locking device 250, the locking mechanism 130, and the tool receiving part 145 therein. For example, the transmission device 170 configured as a planetary gear transmission preferably has at least one annulus 241 and a planet carrier 240 with planet gears 242. Such a planetary gear transmission is well known from the prior art, and thus, for the sake of brevity of the specification here, the detailed description of the working mode of the planetary gear transmission device 170 is omitted.

[0039] The main shaft locking device 250 illustratively has a clamping ring 252 which is supported on a section of the driven main shaft 120 or the planet carrier 240 with a pre-given radial clearance, and at least one main shaft roller 254 is arranged on the clamping ring. It should be noted that the main shaft locking device suitable for implementing the main shaft locking device 250 and its working mode are also well known to those skilled in the art from the prior art, so that the detailed description thereof is also omitted here for the sake of brevity of the specification.

[0040] In addition, the driven main shaft 120 connected to the tool receiving part 145 illustratively has an internal thread 271 at its end facing away from Figure 1 the drive motor 180. As already described in Figure 1 , the tool receiving part 145 is illustratively configured in the type of drill chuck. Therefore, for simplicity, the tool receiving part 145 will also be referred to as the "drill chuck 145" hereinafter. Preferably, the drill chuck 145 is fixed on the external thread of the driven main shaft 120 and is preferably secured on the internal thread 271 with a screw 272.

[0041] The driven main shaft 120 illustratively has an annular ring 281 between the tool receiving part 145 and the locking mechanism 130. The locking mechanism 130 preferably has a first and a second crown plate 222, 220. Preferably, the first crown plate 222 is torsionally connected to the driven main shaft 120. Here, the first crown plate 222 is preferably arranged in a region facing away from the drill chuck 145 in a manner of abutting against the annular ring 281. In addition, the second crown plate 220 is preferably torsionally arranged in the housing 105.

[0042] Preferably, the first crown plate 222 has a section supported on the driven main shaft 120 and having an outer circumference 223. In addition, the second crown plate 220 preferably has an inner circumference 224 on its section facing the outer circumference 223 of the first crown plate 222. Preferably, the outer circumference 223 and the inner circumference 224 are configured such that the first crown plate 222 can move relative to the second crown plate 220, especially axially.

[0043] Preferably, the first crown plate 222 is provided with a locking geometry 292 and the second crown plate 220 is provided with a locking geometry 291. In Figure 2In the position shown, or the first position 310, the first and second crown disks 222, 220 are pressed against each other by the assigned locking geometries 291, 292. In the second position ( Figure 4 410 therein), the second crown disk 220 is arranged spaced apart from the first crown disk 222 along the axis of rotation 109 of the driven main shaft 120.

[0044] Preferably, an annular friction element 230 is provided, which is arranged frictionlessly in the first position 310 and generates a pre-given frictional force between the first and second crown disks 222, 220 in the second position ( Figure 4 410 therein). According to one embodiment, the first crown disk 222 has an outer circumferential groove 227 at its end facing the drive unit 107 for arranging the annular friction element 230. Preferably, the circumferential groove 227 is formed on the outer circumference 223 of the first crown disk 222. Preferably, the annular friction element 230 is an O-ring 232. Preferably, the annular friction element 230 comprises rubber and / or felt.

[0045] During the drilling and / or screwing operation of the hand-held power tool 100, the first and second crown disks 222, 220 are preferably arranged in the second position ( Figure 4 410 therein). The hand-held power tool 100 is shown having a mode selection switch 255 for switching between the assigned drilling and / or screwing mode and the impact mode.

[0046] Preferably, the annular friction element 230 is configured to prevent triggering of the spindle locking device 250 in the second position ( Figure 4 410 therein). In particular, it prevents accidental triggering of the spindle locking device 250 in the second position ( Figure 4 410 therein) or during the drilling and / or screwing operation. The spindle locking device 250 is configured to act when the deceleration of the driven main shaft 120 is greater than the deceleration of the planet carrier 240. Here, the spindle locking device 250 brakes the driven main shaft 120 until the speed of the driven main shaft 120 is less than the speed of the planet carrier 240.

[0047] In Figure 2 the position shown, or the first position 310, the transmission 170 is in the impact mode. Here, the driven main shaft 120 sinks into the transmission and the crown disks 220, 222 are disengaged from each other. The annular friction element 230 does not work here.

[0048] In the percussion mode, the mode selection switch 255 releases the bearing retaining device 212, whereby the driven main shaft 120 is released or movable in the axial direction or along the axis of rotation 109. Preferably, the driven main shaft 120 is equipped with a bearing 214. Preferably, the bearing 214 is fixedly arranged on the outer circumference 282 of the driven main shaft 120 and preferably at least sectionally arranged in the inner receiving part 225 of the second crown plate 220.

[0049] During drilling and / or screwing operation, the bearing retaining device 212 is preferably pushed or loaded to the second position or the right-hand position as shown in Figure 2 by the compression spring 262. Preferably, when no external force acts on the driven main shaft 120, the bearing retaining device 212 is in the second position or the right-hand position. Here, the bearing retaining device 212 loads the bearing 214 and the driven main shaft 120. Here, the axial movement or the movement of the driven main shaft 120 along the axis of rotation 109 is blocked. Here, an annular friction element 230 is arranged between the crown plates 220, 222 and causes a frictional force acting on the driven main shaft 120.

[0050] When no external force acts on the drill chuck 145, this effect can also occur in the percussion mode. Here, the compression spring 262 loads the bearing retaining device 212, the driven main shaft 120 with the bearing 214, the first crown plate 222 and the friction element 230, Figure 2 as shown in to the right. By loading with an externally acting force in the axial direction, the bearing retaining device 212 is loaded or loaded to the first position as shown in to the left. Depending on the position of the mode selection switch 255, the infeed movement is blocked during drilling and screwing operation or released during percussion drilling operation.

[0051] Furthermore, a locking mechanism 130 with first and second crown plates 222, 220 is arranged in the region 299. The region 299 is shown enlarged in the following figures.

[0052] Figure 3 Shows Figure 2 the region 299 and visually shows the locking mechanism 130 in the first position 130. In the first position 310, the first and second crown plates 222, 220 preferably abut against each other by means of their locking geometries 292, 291. Furthermore, in the first position 310, the annular friction element 230 is preferably arranged without friction, i.e. the annular friction element 230 does not exert a frictional force on the driven main shaft 120.

[0053] Figure 4 Shows Figure 2 and Figure 3region 299 and visually shows the latching mechanism 130 in the second position 410. In the second position 410, the second crown disk 220 is preferably arranged spaced apart from the first crown disk 222 along the axis of rotation 109 of the driven main shaft 120. In particular, in the second position 410, the latching geometries 291, 292 are arranged spaced apart from each other.

[0054] According to one embodiment, the inner circumference 224 of the second crown disk 220 is arranged here in the region of the annular friction element 230, wherein a pre-given frictional force is generated between the first and second crown disks 222, 220. In addition, Figure 4 visually shows the region 490 depicted diagrammatically above the axis of rotation 109.

[0055] Figure 5 shows Figure 4 region 490, which has the latching mechanism 130 in the first position 310. According to another embodiment, the annular friction element 230 is arranged here on the inner circumference 224 of the second crown disk 220. For this purpose, the second crown disk 220 preferably has a circumferential groove 227 on its inner circumference 224 for arranging the annular friction element 230.

[0056] Alternatively, the first crown disk 222 has a circumferential collar 510 on its outer circumference 223, which is constructed perpendicular to the axis of rotation 109 of the driven main shaft 120. In Figure 4 the second position 410, in which the annular friction element 230 acts or forms a frictional force, the annular friction element 230 preferably abuts against the circumferential collar 510.

[0057] Figure 6 shows Figure 4 region 490 with the latching mechanism 130, wherein, according to another embodiment, the annular friction element 230 is arranged on the outer circumference 282 of the driven main shaft 120. For this purpose, the driven main shaft 120 preferably has a circumferential groove 227 on its outer circumference 282 for receiving the annular friction element 230.

[0058] Compared with Figures 2 to 5 the embodiment of, according to Figure 6 the embodiment shown, the first crown disk 222 is constructed shorter along the axis of rotation 109. Here, the circumferential groove 227 is preferably arranged in the region of the bearing 214. In addition, compared with Figures 2 - 5 the embodiment of, the annular friction element 230 has a larger diameter. As an alternative to this, the driven main shaft 120 can also have Figure 5 a circumferential collar 510 in order to be able to use the annular friction element 230 according to Figures 2 to 5 the embodiment of.

[0059] It should be noted that the above different embodiments can also be combined with each other. Thus, the latching mechanism 130 can have an annular friction element 230 according to the embodiment of Figures 2 to 4 and a further annular friction element 230 according to the embodiment of Figure 5 . In addition, the latching mechanism 130 can also have a plurality of annular friction elements 230 arranged adjacent to each other, for example, along the rotational axis 109. The desired frictional force can be adjusted by the configuration and arrangement of the annular friction elements 230.

Claims

1. A hand-held power tool (100) having a housing (105) in which a drive unit (107) for driving a driven main shaft (120) is arranged, wherein, The drive unit (107) is provided with a latching mechanism (130) having a first crown disk (222) torsionally connected to the driven main shaft (120) and a second crown disk (220) torsionally arranged in the housing (105), and wherein, in a first position (310), the first and second crown disks (222, 220) abut against each other by means of assigned latching geometries (291, 292), and in a second position (410), the second crown disk (220) is arranged spaced apart from the first crown disk (220) along the rotational axis (109) of the driven main shaft (120), characterized in that an annular friction element (230) is provided which is arranged frictionlessly in the first position (310) and which generates a predefined frictional force between the first and second crown disks (222, 220) in the second position (410).

2. The hand-held power tool according to claim 1, characterized in that The first crown disk (222) has an outer circumferential groove (227) at its end facing the drive unit (107) for arranging the annular friction element (230).

3. The hand-held power tool according to claim 1, characterized in that, The second crown disk (220) has a circumferential groove (227) on its inner circumference (224) for arranging the annular friction element (230).

4. The hand-held power tool according to claim 3, characterized in that, The first crown disk (222) has a circumferential collar (510) constructed perpendicular to the rotational axis (109) of the driven main shaft (120) on its outer circumference (223), wherein, in the second position (410), the annular friction element (230) abuts against the circumferential collar (510).

5. The hand-held power tool according to claim 1, characterized in that The driven main shaft (120) has a circumferential groove (227) on its outer circumference (282) for receiving the annular friction element (230).

6. The hand-held power tool according to any one of claims 1 to 5, characterized in that, The annular friction element (230) is an O-ring (232).

7. The hand-held power tool according to any one of claims 1 to 5, characterized in that, The annular friction element (230) is made of rubber and / or felt.

8. The hand-held power tool according to any one of claims 1 to 5, characterized in that, The drive unit (107) has a spindle locking device (250), wherein the annular friction element (230) prevents triggering of the spindle locking device (250) in the second position.

9. The hand-held power tool according to any one of claims 1 to 5, characterized in that The first and second crown disks (222, 220) are arranged in the second position (410) during drilling and / or screwing operation of the hand-held power tool (100).

10. The hand-held power tool according to any one of claims 1 to 5, characterized in that The drive unit (107) has a planetary gear transmission (170).

11. The hand-held power tool according to any one of claims 1 to 5, characterized in that, The hand-held power tool (100) is configured as an impact drill.

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