Hand planer

Abstract

Hand planer, with a planer shaft (6) rotatably mounted in a housing (2), which can be driven by an electric drive motor (7), and with a fan wheel (9) for generating a cooling airflow (11), wherein at least one cooling channel (15) is integrated into the planer shaft (6), wherein the outflow opening (17) of the cooling channel (15) in the planer shaft (6) has a greater radial distance to the axis of rotation of the planer shaft (6) than the inflow opening (16) of the cooling channel (15) in the planer shaft (6), characterized in that the drive motor (7) is integrated into the hollow cylindrical planer shaft (6) and the cooling airflow (11) is guided axially along the drive motor (7) until it reaches the inflow opening (16) of the cooling channel (15).

Description

[0001] The invention relates to a hand planer according to the preamble of claim 1. State of the art

[0002] Hand planing machines are known, for example from DE 198 53 374 A1, DE 10 2005 062 697 A1, DE 10 2004 063 542 A1, DE 41 34 768 A1, DE 35 42 466 A1, DE 331 635 A and US 2005 / 0 284 543 A1. Disclosure of the invention

[0003] The invention is based on the object of designing a hand planer with effective cooling using simple design measures.

[0004] This object is achieved according to the invention with the features of claim 1. The subclaims specify expedient further developments.

[0005] The hand-held planer according to the invention comprises a rotatably mounted planer shaft in a housing, which is driven by an electric drive motor. Furthermore, the hand-held planer is equipped with a fan wheel, which generates a cooling air flow, which is directed through the housing, particularly along the drive motor. The fan wheel is expediently driven by the drive motor, in particular, it is non-rotatably connected to a rotating part of the drive motor.

[0006] In the hand-held planer according to the invention, at least one cooling duct is integrated into the planer shaft, through which the cooling air flow generated by the fan impeller is directed. The cooling duct in the planer shaft extends at an angle to the planer shaft's rotational axis, with the inlet opening of the cooling duct in the planer shaft being at a smaller radial distance from the rotational axis than the outlet opening. The cooling duct is advantageously formed in a straight line in the planer shaft, although curved designs are also possible if necessary. Due to the oblique course of the cooling duct, with the outlet opening being at a greater radial distance from the rotational axis than the inlet opening, a flow-supporting effect is achieved that supports the flow-generating effect of the fan impeller.The greater distance between the exhaust opening in the cooling channel and the planer shaft creates a suction effect at this point, which is superimposed on the increased pressure at the inlet opening located downstream of the fan wheel. Thus, a cooling air stream is drawn in from the ambient air by the fan wheel and conveyed downstream of the fan wheel into the cooling channel in the planer shaft, which runs radially outward within the planer shaft. The cooling effect is improved due to the supporting effect of the angled cooling channel. The cooling air stream is directed, in particular, along a component of the electric drive motor.

[0007] According to the invention, several cooling channels are incorporated into the planer shaft, distributed around its circumference. For example, it may be expedient to provide a total of twelve cooling channels, whereby the cooling channels can be arranged in groups, for example, in four different segments of three cooling channels each. Advantageously, all cooling channels in the planer shaft have the same angle relative to the planer shaft's rotation axis.

[0008] According to the invention, the planer shaft is hollow-cylindrical, with the inlet opening located on the radially inner side of the planer shaft. The cooling air flow, coming from the fan wheel, is initially directed axially—parallel to the planer shaft rotation axis—through the interior of the hollow-cylindrical planer shaft to the inlet opening. The cooling air flow then flows through the cooling channel of the planer shaft and is discharged via the radially outwardly located outlet opening on the planer shaft. The outlet opening is advantageously located on the end face of the planer shaft facing away from the fan wheel.

[0009] With a hollow-cylindrical planer shaft design, the electric drive motor can be integrated into the interior of the planer shaft. This has the advantage that the cooling air flow can be directed axially along the drive motor until it reaches the inlet opening of the cooling channel on the inside of the planer shaft. The flow through the cooling channel simultaneously cools the planer shaft.

[0010] When the drive motor is integrated into the interior of the hollow cylindrical planer shaft, the motor can either be designed as an external rotor motor, with the rotor located on the outside and firmly connected to the planer shaft. An internal rotor motor is also possible, with the motor shaft being non-rotatably connected to a hollow cylindrical connecting component that is firmly coupled to the planer shaft. In this case, the motor shaft also supports the fan impeller located on the front of the drive motor.

[0011] According to a further advantageous embodiment, the fan impeller also generates a chip removal flow in addition to the cooling air flow, which serves to remove chips generated during workpiece machining, which are sucked into the housing via the fan impeller, from the hand-held planer. If necessary, the mass flow conveyed in the chip removal flow is greater than that of the cooling air flow, for example, twice as large.

[0012] The chip removal flow and the cooling air flow are advantageously guided through the hand planer via different paths. It may be expedient to convey the chip removal flow along an annular channel which is formed in the circumferential direction on the fan wheel or a flange radially surrounding the fan wheel and is axially delimited by a cover which can be fastened to the housing and engages over the fan wheel. One or more air guiding or flow guiding elements can be formed on the inside of the cover, which are preferably formed integrally with the cover and can be used to influence the chip removal flow. For example, it is expedient for the annular channel to have a variable cross-section in the flow direction, in particular to widen radially and / or taper axially along the flow path.A flow guide element, for example, is ramp-shaped and projects axially into the annular channel, thereby axially reducing the cross-section of the annular channel. Several partial flows of the chip removal flow can be generated or directed via the flow guide element(s). For example, a first partial flow of the chip removal flow is accelerated within the fan wheel by the rotation and thrown radially or tangentially into a section of the annular channel, where it merges with the air flow through the annular channel. The entire chip removal flow can then flow into a discharge channel that extends transversely to the longitudinal axis of the hand planer through the housing, so that on the side opposite the fan wheel the chip removal flow is guided out of the housing, whereby the chip removal flow entrains the chips created by the knife on the planer shaft during processing.

[0013] Further advantages and practical embodiments can be found in the further claims, the description of the figures, and the drawings. They show: Fig. 1 in perspective view a hand planer, Fig. 2 a cross-section through the hand planer, in whose planing shaft cooling channels are integrated, which extend at an angle to the planing shaft rotation axis, with a fan wheel driven by the drive motor, Fig. 3 a view of the front of the hand planer below the fan wheel, with several inlet openings through which the air flow generated by the fan wheel is directed into the interior of the hand planer, Fig. 4 a view of the front side of the planer shaft on the side facing away from the fan wheel, with several outflow openings of the cooling channels, which are incorporated in the planer shaft, Fig. 5 in perspective view a cover which can be placed on the fan wheel and connected to the housing of the hand planer, Fig. 6 the lid in another perspective view, Fig. 7 the fan wheel in mounted position on the hand planer without the cover attached, Fig. 8 a detailed view of the air flow of a chip removal stream through which chips are blown out of the hand planer, Fig. 9 a further perspective view of the hand planer with an outlet opening in the side housing area for discharging the chip discharge flow.

[0014] In the figures, identical components are provided with identical reference symbols.

[0015] In Fig. 1 shows a hand-held planer 1, which has an electric drive motor and a planer shaft in a housing 2, which is rotatably mounted in the housing and driven by the drive motor. The planer shaft has one or more knives with a cutting edge on its circumference, which removes workpiece material during workpiece processing. On the underside of the housing 2 there is a base plate 3, which rests on the upper side of the workpiece and has a recess through which the knife of the planer shaft protrudes. Furthermore, a handle 4 for holding and guiding the hand-held planer is arranged on the housing 2. A cover 5 is arranged on the side of the housing and connected to it; the cover 5 covers a fan wheel, which is seated axially on the front of the electric drive motor and is driven by the latter. The hand-held planer 1 can be equipped with a planing depth adjustment.

[0016] As shown in the sectional view Fig. As can be seen from Figure 2, the planer shaft 6 is hollow-cylindrical and accommodates the coaxially arranged electric drive motor 7 within its interior. The motor shaft 8 of the drive motor 7 carries the fan wheel 9, which is non-rotatably connected to the motor shaft 8 and is arranged on the front side of the drive motor 7 or the planer shaft 6. The fan wheel 9 is overlapped by the cover 5, which is connected to the housing 2.

[0017] The drive motor 7 has a connecting part 10 that is connected to the motor shaft 8 and rotates together with it. The connecting part 10 is hollow-cylindrical and rests against the inner wall of the planer shaft 6. It is firmly connected to the planer shaft 6, so that when the drive motor 7 is running, the planer shaft 6 is also driven.

[0018] The fan impeller 9 generates two air streams that are guided through the housing of the hand-held planer 1 and serve different functions. A first air stream 11 is directed axially along the drive motor 7 as a cooling air stream to cool it. A second air stream 12 serves as a chip removal stream, through which chips generated during workpiece machining are removed from the housing of the hand-held planer and expelled back to the outside. Both air streams 11, 12 are introduced into the housing 2 via ventilation slots in the cover 5.

[0019] The fan wheel 9 extends no further outwards in the radial direction than the planer shaft 6, which has a larger outer diameter than the fan wheel 9. The cooling air flow 11 is offset radially further inwards than the chip removal flow 12.

[0020] The cooling air flow 11 is guided axially along the inside of the hollow cylindrical connecting part 10 on the drive motor 7. A cylindrical or annular channel 18 is formed between the connecting part 10 and the radially inner stator 13 of the drive motor 7, which extends in the axial direction relative to the rotational axis 14 of the planer shaft 6 and the motor shaft 8.

[0021] On the downstream side of the first cooling channel section 18 between the stator 13 and the cylindrical connecting part 10, the cooling air flow 11 enters cooling channels 15 formed in the planer shaft 6. The cooling channels 15 are linear and extend at an angle to the rotational axis 14, which in the exemplary embodiment is approximately 30°. Each cooling channel 15 has an inlet opening 16 on the radially inner side of the planer shaft 6 and an outlet opening 17 on the end face of the planer shaft, which faces away from the fan wheel 9. Due to the oblique course of the cooling channel 15, the inlet opening 16 has a smaller radial distance from the rotation axis 14 than the outlet opening 17. When the planer shaft 6 rotates, this supports the flow path from the cooling channel section 18 into the cooling channels 15. Downstream of the outlet opening 17, the cooling air flow can reach the environment via slots in the housing.

[0022] Between the fan wheel 9 and the drive motor 7 there is a cover plate 19 on the housing side, into which, as Fig. 3, flow openings 20 are provided. The cooling air flow 11 passes through the flow openings 20 into the first cooling channel section 18 and from there into the cooling channels 15 in the planer shaft 6.

[0023] In Fig. Figure 4 shows the end face 21 of the planer shaft 6. The cooling channels 15, which are incorporated into the planer shaft 6, open with their outlet openings 17 at the end face 21. A total of twelve cooling channels, each with an outlet opening 17, are incorporated into the planer shaft 6, distributed around the circumference. The cooling channels with the outlet openings 17 are each grouped into three closely adjacent cooling channels, each located in a 90° angular segment.

[0024] Fig. 4 also shows the knife 22, which is arranged on the planing shaft 6 and periodically projects through a recess in the base plate 3 when the planing shaft rotates.

[0025] In the Fig. 5 and Fig. Figure 6 shows the cover 5, which overlaps the fan wheel when installed. The cover 5 has mounting lugs 23 and 24, which allow attachment to the housing of the hand planer.

[0026] Adjacent to the annular outer wall, a circumferentially extending annular channel 25 for the chip removal channel 12 is formed in the cover 5. The cover 5 defines the chip removal channel axially and radially outward. In the assembled state, the annular channel 25 is defined radially inward by the outer side of the fan wheel 9.

[0027] In the direction of flow, the cross-section of the annular channel 25 expands radially. A flow guide element 26 is formed integrally with the outer wall of the cover 5 and limits the flow cross-section of the annular channel 25 in the axial direction. As shown in the illustration, Fig. 6, the flow guide element 26 is ramp-shaped and limits the flow cross-section in the flow direction axially in an increasing manner.

[0028] The ring channel 25 is also in the housing side Fig. 7. In conjunction with further Fig. 8 and Fig. 9 it can be seen that the chip removal flow 12 opens into a discharge channel 27 in the housing, which extends transversely to the longitudinal axis of the hand planer 1 through the housing 2 and guides the chip removal flow 12 transversely through the housing from the fan wheel 9 to the opposite side of the hand planer and releases it into the environment at this point.

[0029] According to Fig. 8 and Fig. 9, the chip removal flow is divided into a first partial flow 12 and a second partial flow 12a, wherein the first partial flow 12 is guided, as described above, through the annular channel 25 in the circumferential direction between the outside of the fan wheel 9 and the inside of the cover 5. The second partial flow 12a is located inside the fan wheel 9 and flows into the last section of the annular channel 25 ( Fig. 8), which merges at a 90° angle into the transversely extending discharge channel 27. The ramp-shaped flow guide element 26 on the cover 5 deflects the first partial flow 12 axially in the annular channel 25, so that in the end section of the annular channel 25, as Fig. 8, the first and second partial streams 12 and 12a flow parallel and at different levels in the direction of the discharge channel 27.

Claims

[1] Hand planer, with a planing shaft (6) rotatably mounted in a housing (2), which can be driven by an electric drive motor (7), and with a fan wheel (9) for generating a cooling air flow (11), wherein at least one cooling channel (15) is integrated into the planing shaft (6), wherein the outflow opening (17) of the cooling channel (15) in the planing shaft (6) has a greater radial distance from the planing shaft rotation axis than the inflow opening (16) of the cooling channel (15) in the planing shaft (6), characterized by that the drive motor (7) is integrated into the hollow cylindrical planing shaft (6) and the cooling air flow (11) is guided axially along the drive motor (7) until it reaches the inlet opening (16) of the cooling channel (15). [2] Hand planer according to claim 1, characterized by that the planing shaft (6) is hollow-cylindrical and the inlet opening (16) of the cooling channel (15) is located on the radial inside of the planing shaft (6). [3] Hand planer according to claim 1, characterized by that the rotor or the motor shaft (8) of the drive motor (7) is firmly connected to the planer shaft (6). [4] Hand planer according to one of claims 1 to 3, characterized by that the outflow opening (17) of the cooling channel (15) is located on the front side (21) of the planing shaft (6). [5] Hand planer according to one of claims 1 to 4, characterized by that several cooling channels (15) are provided distributed over the circumference of the planing shaft (6). [6] Hand planing machine according to one of claims 1 to 5, characterized by that the fan wheel (9) is covered by a cover (5) which can be fastened to the housing (2), an annular channel (25) extending in the circumferential direction being formed between the inside of the cover and the fan wheel (9). [7] Hand planer according to claim 6, characterized by that the annular channel (25) has a variable cross-section over its length. [8] Hand planer according to claim 7, characterized by that a flow guide element (26) protrudes into the annular channel (25) and is formed in one piece with the cover (5). [9] Hand planer according to claim 9, characterized by that the flow guide element (26) is ramp-shaped and axially tapers the cross section of the annular channel (25). [10] Hand planer according to claim 8 or 9, characterized by that downstream of the flow guide element (26) an air flow generated directly by the fan wheel (9) flows into the annular channel (25). [11] Hand planing machine according to one of claims 6 to 10, characterized by that the annular channel (25) opens into a discharge channel (27) which extends transversely to the longitudinal axis of the hand planer (1) through the housing (2).

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