Chain saw

Abstract

The invention relates to a chain saw (2) having a motor (20) and a transmission (30), in particular a motor-transmission unit (10), and having a housing (3), the motor (20) and the transmission (30) being arranged at least partially in the housing (3), the transmission (30) having a planetary transmission (30), the planetary transmission (30) being arranged in the housing (3), and the planetary transmission (30) being arranged in the housing (3). The planetary gear (30) has at least one rotationally fixed ring gear (32), a sun gear (31) which can be driven by the motor (20), and at least one planet gear (37) which is mounted on a planet carrier (34). According to the invention, a sprocket (41) for driving the saw chain (42) is integrally formed with the planet carrier (34).

Description

Field of the Invention

[0001] The present invention relates to a chainsaw, in particular a chainsaw with an electric drive, such as a single-handed chainsaw, i.e., a chainsaw that is at least configured to be operated with one hand. Background Art

[0002] Chainsaws with the features of the preamble of claim 1 are known from the prior art. Summary of the Invention

[0003] The present invention relates to a chainsaw having the features of claim 1. Advantageous refinements result from the dependent claims.

[0004] The object of the present invention may be to provide an improved hand-held power tool in the form of a chainsaw. The hand-held power tool can be configured more compactly than chainsaws known from the prior art.

[0005] The present invention is based on a chainsaw having a motor and a transmission, in particular a motor-transmission unit, and having a housing, wherein the motor and the transmission are at least partially arranged in the housing, wherein the transmission has a planetary gear, and wherein the planetary gear has at least one torsion-resistant hollow wheel, a sun wheel that can be driven by the motor, and at least one planet wheel supported on a planet carrier.

[0006] It is proposed that the sprocket for driving the saw chain is integrally formed with the planet carrier.

[0007] The chainsaw is preferably a single-handed chainsaw. The motor is preferably an electric motor. The chainsaw in particular has a motor-transmission unit. The motor-transmission unit can be at least partially arranged in the housing. The motor-transmission unit in particular has an electric motor and a planetary gear. It can be provided that the planetary gear has a plurality of planet wheels supported on the planet carrier, for example two, three or four planet wheels. The output element of the motor-transmission unit, in particular the sprocket for driving the saw chain, is integrally formed with the planet carrier. The planet carrier is supported, in particular rotatably supported, on the housing by means of a planet carrier bearing. The "torsion-resistant (drehfest) hollow wheel" can in particular be understood as meaning that the hollow wheel is constructed to be immovable in the circumferential direction, but can be axially movable and / or tiltable relative to the axis of rotation or swingable about the axis of rotation. Thereby, for example, tolerances can be compensated, a sinking movement (Setzbewegung) can be achieved and / or a low-force or low-friction support or rolling of the planet wheel and / or the planet carrier can be achieved.

[0008] This arrangement allows for a compact configuration of the chainsaw. It can be provided that the hollow wheel is fixed in position. This can in particular mean that the hollow wheel can be non-axially movable, i.e., cannot be axially moved.

[0009] In one embodiment, when the hand-held power tool or the chainsaw is running, the output element or the sprocket is loaded unilaterally. This unilateral load can be caused, for example, by the chain of the chainsaw, but alternative configurations of the hand-held power tool can also be considered, in which the output element is loaded unilaterally. In such a configuration, it can be provided in particular that the output element or the sprocket and the planet carrier are supported only by the planet carrier bearing, so that in particular no additional bearings are provided for the planet carrier or the output element or the sprocket.

[0010] It is proposed that the central shaft is supported on the housing by means of a first central shaft bearing. The sun gear is fixedly connected to the central shaft. This connection can in particular be configured as a press fit or have other shaft-hub connections. The first central shaft bearing can here be a sliding bearing or a rolling bearing, for example a ball bearing. The motor can in particular be an electric motor. The rotor of the electric motor can be fixedly connected to the central shaft. This connection can be configured, for example, as a press fit, but can also be configured as a key connection or the like. The stator of the electric motor can at least partially, in particular completely, surround or enclose the rotor. The compact structure of the hand-held power tool or the chainsaw is further supported by the central shaft which is simultaneously connected to the sun gear of the planetary gear train.

[0011] It is proposed that the central shaft is supported on the planet carrier by means of a second central shaft bearing. The second central shaft bearing can in particular be a rolling bearing or a sliding bearing, for example a ball bearing. This enables a stable structure. Alternatively, it can be provided that the central shaft is supported only by the sun gear of the planetary gear train and no separate second central shaft bearing is provided.

[0012] It is proposed that the second central shaft bearing is at least partially, in particular completely, arranged in the inner region of the planet carrier bearing. In particular, the planet carrier bearing can have an inner cylinder, in which the planet carrier is at least partially arranged. The second central shaft bearing can be partially and in particular completely arranged within the inner cylinder of the planet carrier bearing. The second central shaft bearing can be arranged in the inner cylinder of the planet carrier.

[0013] It is proposed that the motor is an electric motor and the rotor and the sun gear are arranged between the first central shaft bearing and the second central shaft bearing. This also enables a compact structure of the hand-held power tool. In one embodiment, the rotor, the fan element and the sun gear are arranged between the first central shaft bearing and the second central shaft bearing.

[0014] It is proposed that the planet gears are supported on the planet carrier by means of needle bearings. Thereby, the stability of the motor and the transmission and / or the transmission and the sprocket can be increased, in particular when the output element is loaded unilaterally, preferably when the hand-held power tool is running.

[0015] It is proposed that the motor is an electric motor and a fan element is arranged between the rotor and the sun gear, and the fan element is connected to the central shaft. The fan element can be connected to the central shaft by means of a press fit in particular. The fan element can contribute to the cooling of the electric motor, thereby improving the efficiency of the electric motor. By arranging it between the sun gear and the rotor, a compact configuration of the hand-held power tool can be supported.

[0016] It is proposed that the fan element is arranged in a fan housing. The opening of the fan housing is connected to the housing opening of the housing. This can improve the ventilation effect.

[0017] It is proposed that the fan element is an impeller. The impeller has fastening elements. The fastening elements are fastened to the central shaft, for example by means of a press fit. The impeller is fastened to the fastening elements. The fastening elements can be injection-molded or cast by the impeller here. The impeller can contain or consist of plastic. The fastening elements can have a metal centering ring or be a metal centering ring.

[0018] Another housing opening can be provided, which points to the same side as the housing opening and is suitable for discharging sawdust. Preferably, the housing openings are offset from each other along the central axis. In particular, one or more housing openings are configured to guide the exhaust gas along the outer guard bow region of the guard. Thus, it is possible to guide the sawdust away from the hand holding the hand-held power tool.

[0019] It is proposed that the hollow wheel has at least one radial protrusion, by means of which the rotation of the hollow wheel around the central axis can be at least restricted. The central axis can correspond to the central shaft and / or the central axis of the electric motor here. The radial protrusion is arranged outward in particular. A plurality of radial protrusions can also be provided, such as two, three or four radial protrusions. By means of one or more radial protrusions, it is possible to make the hollow wheel torsion-resistant. It can be provided that, despite the protrusions, it is still possible to achieve the axial movement of the hollow wheel and / or the tilting movement of the hollow wheel along the central axis and / or the rocking movement around the central axis in particular.

[0020] It is proposed that the protrusion is arranged in a corresponding element of the housing. The corresponding element can be a form-locking element. If necessary, a corresponding element can be provided for each radial protrusion. The corresponding element can be configured as a groove in the housing in the direction parallel to the central axis. The side walls of the groove prevent the protrusion from twisting around the central axis. However, the groove enables the axial movement of the protrusion. Therefore, the protrusion can be torsion-resistant but not position-fixed. The corresponding element can restrict the movement of the hollow wheel in the circumferential direction in particular, and a clearance can be reserved in the axial direction. Thereby, for example, tolerances can be compensated. The hollow wheel can be tilted at least slightly relative to the central axis. Unilateral loads on the output element or the planet carrier and / or the planet gears can be compensated. A jam-free rolling of the transmission, in particular the planet gears, can be achieved. However, the corresponding element can provide a torsion-resistant but not position-fixed reception for the protrusion in particular.

[0021] It is proposed that the chain, or rather the saw chain, is guided around the guide bar. The central axis, or rather the central shaft, is substantially perpendicular to the guide bar, in particular at an angle between 80 and 100 degrees, preferably between 89 and 91 degrees, with respect to the guide bar.

[0022] It is proposed that the first central shaft bearing is arranged in the central shaft bearing receiving part of the housing. The planet carrier bearing is arranged in the planet carrier bearing receiving part of the housing. Description of the Drawings

[0023] Embodiments of the present invention will be described with reference to the following drawings. Shown in the schematic diagrams are:

[0024] Figure 1 : A view of a hand-held power tool in the form of a chainsaw;

[0025] Figure 2 : A cross-section of the hand-held power tool;

[0026] Figure 3 : Another cross-section of the hand-held power tool;

[0027] Figure 4 : Another cross-section of the hand-held power tool;

[0028] Figure 5 : Another cross-section of the hand-held power tool; and

[0029] Figure 6 : Another cross-section of the hand-held power tool. Detailed Description of the Embodiments

[0030] Figure 1 A view showing the hand-held power tool 1: The hand-held power tool 1 is configured as a chainsaw 2. The hand-held power tool 1 includes a housing 3. The motor 20 and the transmission 30 are at least partially arranged in the housing 3, in particular as a motor-transmission unit 10. In addition, Figure 1 the power supply device 8 is shown, which is configured as a storage battery in this case, in particular a rechargeable battery pack. Alternatively, it may also be provided that the power supply device 8 is realized by means of a cable. In addition, the housing 3 of the hand-held power tool 1 particularly has a hand guard 9. The hand-held power tool 1 can be driven by means of the motor-transmission unit 10. If the hand-held power tool 1 is Figure 1 configured as a chainsaw 2 as shown, the saw chain 42 can in particular be driven by means of the motor-transmission unit 10.

[0031] Figure 2 Shown Figure 1 is a cross-section of the hand-held power tool 1. The motor-transmission unit 10 has an electric motor 20 and a planetary transmission 30. The electric motor 20 can be, for example, Figure 1The power supply device 8 shown is supplied with direct current or alternating current. In particular, the electric motor 20 is a brushless DC motor. However, in principle, other motors, such as internal combustion engines or hydraulic motors, etc., can also drive the hand-held power tool 1. The planetary gear 30 has at least one torsion-resistant ring gear 32, a sun gear 31 that can be driven by the motor 20, and at least one planet gear 37 supported on the planet carrier 34. The output element 40 of the transmission 20, in particular of the motor-transmission unit 30, is constructed here as a sprocket 41 for driving the saw chain 42. This sprocket is connected to the planet carrier 34 or is integrally formed with the planet carrier 34. The planet carrier 34 is supported on the housing 3 by means of planet carrier bearings 35.

[0032] It can be provided that the ring gear 32 is stationary. This can in particular mean that the ring gear 32 is axially immovable, i.e., cannot move axially. In particular, it can be provided that the ring gear 32 cannot move to the left or right in the Figure 2 configuration. In another configuration, it can be provided that the ring gear 32 has an axial clearance and can move at least a small range to the left or right in the Figure 2 configuration.

[0033] It can be provided that the planetary gear 30 has a plurality of planet gears 37 supported on the planet carrier 34, for example two, three or four planet gears 37. Here, three planet gears 37 are provided.

[0034] In one embodiment, when the hand-held power tool 1 is running, the output element 40 is loaded unilaterally. This unilateral load can in particular be caused by the saw chain 42 of the chain saw 2, but alternative configurations of the hand-held power tool 1 can also be considered, in which the output element 40 is loaded unilaterally. The output element 40 and the planet carrier 34 can be supported only by means of the planet carrier bearings 35, such that in particular no additional bearings are provided for the planet carrier 34.

[0035] The central shaft 11 can be supported on the housing 3 by means of a first central shaft bearing 12. The sun gear 31 can be fixedly connected to the central shaft 11. The first central shaft bearing 12 can here be a sliding bearing or a rolling bearing, for example a first ball bearing 13. The rotor 21 of the electric motor 20 can be fixedly connected to the central shaft 11. The stator 25 of the electric motor 20 can at least partially surround the rotor 21. The connection between the rotor 21 and the central shaft 11 can be realized, for example, by means of a press fit, but can also be configured as a key connection, etc. It can be provided that the stator 25 completely surrounds the rotor 21. In particular, the stator 25 can surround the rotor 21. The connection between the sun gear 31 and the central shaft 11 can in particular be configured as a press fit or other shaft-hub connection. By means of the central shaft 11 that is simultaneously connected to the sun gear 31 of the planetary gear 30 and the rotor 21 of the electric motor 20, a compact structure of the hand-held power tool 1 can be obtained.

[0036] The rotor 21 may include a rotor magnet 22, and the stator 25 includes a stator winding 26. Energizing the stator winding 26 can in particular cause a rotational movement of the rotor 21.

[0037] The central shaft 11 can be supported on the planet carrier 34 by means of a second central shaft bearing 14. The second central shaft bearing 14 can in particular be a rolling bearing or a sliding bearing, for example a second ball bearing 15. This enables a stable structure. Alternatively, it can be provided that the central shaft 11 is supported only by the sun gear 31 of the planetary gear unit 30 and no separate second central shaft bearing 14 is provided. If the second central shaft bearing 14 is omitted, this configuration is obtained (not shown in Figure 2 ).

[0038] The second central shaft bearing 14 can be at least partially arranged in the inner region of the planet carrier bearing 35. In particular, the second central shaft bearing 14 can be completely arranged in the inner region of the planet carrier bearing 35. In particular, the planet carrier bearing 35 can have an inner cylinder in which the planet carrier 34 is at least partially arranged. The second central shaft bearing 14 can be partially and in particular completely arranged within the inner cylinder of the planet carrier bearing 34. In particular, it can be provided that a cross-section through the hand-held power tool 1 perpendicular to the central shaft 11 (and also perpendicular to Figure 2 the drawing plane) intersects not only the planet carrier bearing 35 but also the second central shaft bearing 14. In this arrangement, the second central shaft bearing 14 is at least partially arranged in the inner region of the planet carrier bearing 35.

[0039] The rotor 21 and the sun gear 31 can be arranged between the first central shaft bearing 12 and the second central shaft bearing 14. The planet gears 37 can be supported on the planet carrier 34 by means of needle bearings 38. The first central shaft bearing 12 can be arranged in the central shaft bearing receiving part 4 of the housing 3. The planet carrier bearing 35 can be arranged in the planet carrier bearing receiving part 5 of the housing 3. A fan element 51 can be arranged between the rotor 21 and the sun gear 31, and this fan element is connected to the central shaft 11. The fan element 51 can in particular be connected to the central shaft 11 by means of a press fit or by means of a key connection. The fan element 51 can in particular contribute to the cooling of the electric motor 20 and thus in particular improve the efficiency of the electric motor 20. By being arranged between the sun gear 31 and the rotor 21, a compact configuration of the motor-drive unit 10 and thus of the hand-held power tool 1 can be supported.

[0040] Figure 3 Shows a further cross-section of the hand-held power tool 1 through the Figure 2 section plane denoted by A in Figure 1 and Figure 2 The fan element 51 can be arranged in a fan housing 54, where an opening 55 of the fan housing 54 is connected to the housing opening 6 of the housing 3. This can improve the ventilation effect.

[0041] The fan element 51 may have an impeller 52 and a fastening element 53. The fastening element 53 may be fastened to the central shaft 11. The fastening element 53 may be fastened to the central shaft 11, for example, by means of a press fit or a key connection. The impeller 52 may be fastened to the fastening element 53. Here, the fastening element 53 may be injection-molded or cast by the impeller 52. The fastening element 53 may have or be a metal centering ring. The impeller 52 may comprise or be made of plastic, in particular comprise or be made of a plastic composite material.

[0042] In Figure 3 another housing opening 56 is shown, which points to the same side as the housing opening 6 and is suitable for discharging sawdust. Preferably, the housing openings 6, 56 are offset from each other along the central axis. In particular, one or more housing openings 6, 56 are configured to guide the exhaust gas along the outer guard bow region 57 of the guard 9. Thus, it is possible to guide the sawdust away from the hand holding the hand-held power tool.

[0043] Figure 4 Shown by Figure 2 the cross-section of the hand-held power tool 1 represented by B in Figures 1 to 3 is another cross-section. The hollow wheel 32 may have at least one radial protrusion 33, by means of which the rotation of the hollow wheel 32 about the central axis can be at least restricted, in particular prevented. The central axis may here correspond to the central shaft 11, be arranged parallel to the central shaft 11 or be the central axis of the electric motor 20. The radial protrusion is arranged outward in particular. The radial protrusion has in particular a rectangular basic shape. It is also possible to provide a plurality of radial protrusions 33, for example two, three, four or more radial protrusions 33. Here, three protrusions are provided. Alternatively, as a protrusion, as a covering of the protrusion or instead of the protrusion, in particular as a covering of the hollow wheel, elastic connecting elements, in particular elastic rings, for example made of a rubber-elastic material, may also be provided. By means of one or more radial protrusions 33, the hollow wheel can be held torsionally resistant on the housing 3. The corresponding element 7 may also be elastically configured, in particular axially and / or radially elastically with respect to the central axis, for example in order to enable a slight movement of the hollow wheel in the axial, radial and / or circumferential directions.

[0044] The protrusion 33 may be arranged in the corresponding element 7 of the housing 3. The corresponding element 7 may be a form-fitting element. If necessary, a corresponding element 7 may be provided for each radial protrusion 33. The corresponding element 7 can in particular restrict the movement of the hollow wheel 32 in the circumferential direction, wherein in particular a clearance in the axial direction can be retained. For this purpose, the corresponding element 7 can in particular be configured as a groove in the direction parallel to the central axis.

[0045] Instead of the radial projections 33 and the corresponding elements 7, it is also possible to provide that the housing element is inserted into the groove of the annulus 32, thereby also at least restricting the rotation of the annulus 32 about the central axis (not shown).

[0046] By means of the radial projections 33 and the corresponding elements 7 or alternatively by means of the housing element (not shown) and the groove of the annulus 32, it is in particular possible to achieve self-centering of the annulus 32, such that there is a certain clearance during running-in, starting and / or under load during operation of the hand-held power tool 1, such that the probability of damage to the planetary gear 30 can be reduced, and thus for example the service life of the hand-held power tool 1 can be increased. The radial projections 33 are arranged in such a way that they are evenly distributed on the annulus 32, here being arranged relative to each other at an angle of 120 degrees. Of course, other angles are also possible, and the radial projections 33 can also be unevenly distributed. Figure 4 in such a way that they are evenly distributed on the annulus 32, here being arranged relative to each other at an angle of 120 degrees. Of course, other angles are also possible, and the radial projections 33 can also be unevenly distributed.

[0047] The transmission ratio of the planetary gear 30 can in particular be between 3 and 6, for example 3.6 or 4.6 or 5.5. This can mean that the sun gear 31 rotates three to six times, in particular 3.6 times, 4.6 times or 5.5 times faster than the planet carrier 34. The transmission ratio can be determined by appropriately selecting the number of teeth of the annulus 32, the planet gears 37 and / or the sun gear 31.

[0048] Likewise shown in Figure 4 is that the planetary gear 30 includes three planet gears 37, which have three needle roller bearings 38, and these needle roller bearings are respectively arranged on the bearing pins 39. The bearing pins 39 can be inserted into the planet carrier 34 here, for example as a press fit, such that the bearing pins 39 are fixedly connected to the planet carrier 34.

[0049] Figure 5 Shown by Figure 2 is another cross-section of the hand-held power tool 1 through the cutting plane denoted by C in Figures 1 to 4 . This cutting plane guides through the planet carrier bearing 35 and the second central shaft bearing 14. Thus, the planet carrier bearing 35 and the second central shaft bearing 14 at least share Figure 5 the cutting plane, such that the second central shaft bearing 14 is at least partially arranged within the planet carrier bearing 35. In particular, the second central shaft bearing 14 can be completely arranged within the planet carrier bearing 35.

[0050] Figure 6 Shown by Figure 2 is another cross-section of the hand-held power tool 1 through the cutting plane denoted by D in Figures 1 to 5 . The output element 40 is a sprocket 41. The sprocket 41 drives a chain 42 or a saw chain 42. In one embodiment, as also shown in Figure 6 the sprocket 41 and the planet carrier 34 are integrally constructed.

[0051] The chain 42 can be guided around the chain guide plate 43. The central axis 11 can be substantially perpendicular to the chain guide plate 43. This can especially mean that the angle between the central axis 11 and the chain guide plate 43 is between 80 and 100 degrees, preferably between 89 and 91 degrees.

[0052] Although the present invention has been described in detail, the present invention is not limited to the disclosed examples, and other variations can be derived therefrom by those skilled in the art without departing from the scope of protection of the present invention.

Claims

1. A chain saw (2), having a motor (20) and a transmission (30), in particular a motor-transmission unit (10), and having a housing (3), wherein, The motor (20) and the transmission (30) are at least partially arranged within the housing (3), wherein the transmission (30) has a planetary gear (30), and wherein the planetary gear (30) has at least one torsion-resistant annulus (32), a sun gear (31) drivable by the motor (20), and at least one planet gear (37) supported on a planet carrier (34), characterized in that a sprocket (41) for driving a saw chain (42) is integrally formed with the planet carrier (34).

2. The chainsaw (2) according to claim 1, wherein, The sprocket (41) integrally formed with the planet carrier (34) is supported on the housing (3) by means of a planet carrier bearing (35).

3. The chainsaw (2) according to claim 1 or 2, wherein, The sprocket (41) is loaded unilaterally, especially when the chain saw (2) is operating.

4. The chainsaw (2) according to claims 1 to 3, wherein, The central shaft (11) is supported on the housing (3) by means of a first central shaft bearing (12), wherein the sun gear (31) is fixedly connected to the central shaft (11), especially wherein the motor (20) is an electric motor (20) and the rotor (21) of the electric motor (20) is fixedly connected to the central shaft (11), preferably wherein the stator (25) of the electric motor (20) at least partially surrounds the rotor (21).

5. The chainsaw (2) according to claim 4, wherein, The central shaft (11) is supported on the planet carrier (32) by means of a second central shaft bearing (14).

6. The chainsaw (2) according to claim 5, wherein, The second central shaft bearing (14) is at least partially arranged in an inner region of the planet carrier bearing (35).

7. The chain saw (2) according to claim 5 or 6, wherein, The motor (20) is an electric motor (20) and the rotor (21) of the electric motor (20) is fixedly connected to the central shaft (11), wherein the rotor (21) and the sun gear (31) are arranged between the first central shaft bearing (12) and the second central shaft bearing (14).

8. A chainsaw (2) according to any one of claims 4 to 7, wherein, The motor (20) is an electric motor (20) and the rotor (21) of the electric motor (20) is fixedly connected to the central shaft (11), wherein a fan element (51) is arranged between the rotor (21) and the sun gear (31) and the fan element is connected to the central shaft (11).

9. The hand-held power tool (1) according to any one of claims 1 to 8, wherein, The planet gear (37) is supported on the planet carrier (34) by means of needle bearings (38).

10. The chainsaw (2) according to claim 8, wherein, The fan element (51) is arranged in a fan housing (54), wherein an opening (55) of the fan housing (54) is connected to a housing opening (6) of the housing (3), especially wherein the housing opening (6) and another housing opening (56) for discharging sawdust open towards the same side, preferably wherein the housing openings (6, 56) are offset relative to each other along the central axis, especially wherein the housing openings (6, 56) are configured to guide exhaust gas along an outer guard bow region (57) of the guard (9).

11. The chain saw (2) according to claim 8 or 10, wherein, The fan element (51) has an impeller (52) and a fastening element (53), wherein the fastening element (53) is fastened to the central shaft (11), and wherein the impeller (52) is fastened to the fastening element (53).

12. A chainsaw (2) according to any one of claims 1 to 10, wherein, The hollow wheel (32) has at least one radial projection (33), wherein the rotation of the hollow wheel (32) about the central axis can be at least restricted by means of the projection (33), preferably wherein, despite the projection (33), axial movement of the hollow wheel (32) and / or tilting movement of the hollow wheel (32) along the central axis and / or rocking movement of the hollow wheel (32) about the central axis can be achieved.

13. The chain saw (2) according to claim 12, wherein, The projection (33) is arranged in a corresponding element (7) of the housing (3), preferably wherein the corresponding element (7) is configured as a groove in the housing (3) in the direction parallel to the central axis, in particular wherein the corresponding element (7) provides a torsion-resistant but non-position-fixed reception for the projection (33).

14. A chainsaw (2) according to any one of claims 1 to 13, wherein, The saw chain (42) is guided around a guide bar (43), wherein the central axis (11) is substantially perpendicular to the guide bar (43), preferably at an angle between 89 degrees and 91 degrees.

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