HOUSING FOR AN ELECTRIC HAND TOOL MACHINE

Description

[0001] The invention relates to a housing for an electric hand tool and the electric hand tool comprising this housing, in particular an angle grinder.

[0002] Power tools typically have a housing that can be opened for maintenance. Such maintenance is necessary, for example, when wear parts need to be inspected or replaced. Statistical observations have identified the power cord and its end section, which runs through an opening in the housing into the interior where the cord's wires are connected to terminals, as potential wear parts in power tools. Because power cords are frequently moved by the user, the cable ends, despite the often-used bend protection sleeves, exhibit a statistical residual susceptibility to cable breakage, intermittent contact, or other damage.

[0003] Opening the housing for maintenance purposes, on the other hand, poses a risk to the operational readiness of the power tool, as contaminants can unintentionally reach sensitive components during opening, or components can be accidentally manipulated and / or damaged by the user. The invention is based on the observation that the vast majority of components located in the housing rarely fail during the power tool's service life.

[0004] US 2018 / 366286 A1 discloses an electric hand-held power tool according to the preamble of claim 1.

[0005] The present invention therefore aims to provide an electric hand tool with a housing in which maintenance of wear-prone parts can be carried out efficiently and with a reduced risk to the operational capability of the other components of the electric hand tool.

[0006] This problem is solved by independent claim 1. Preferred technical solutions and preferred embodiments of the electric hand tool according to claim 1 can be found in the description and the figures and their descriptions. The maintenance cover of the housing offers the advantage that a large part of the housing interior can remain closed when maintenance of the power cord end is required. Only the limited area of ​​the interior section located under the maintenance cover is exposed, allowing maintenance of the power cord end, the electrical conductors exiting it, their contact points, and the condition of the contact points. In a preferred embodiment, the housing, and in particular the maintenance cover, is designed such that the power cord conductors can be disconnected from the contact points, especially when the housing is closed.In a further preferred embodiment, the housing, in particular the maintenance cover, is arranged such that the end of the power cord can be removed from the housing, especially in the open position of the maintenance cover.

[0007] An internal section is understood to be, in particular, that section of the housing interior enclosed by the housing in which, when the power cord is attached to the closed housing or a power tool, the end of the power cord runs inside the housing, and in which, in particular, the ends of the power cord and, especially, the contact points for connecting the power cord are located. More generally, the internal section is that section of the housing interior in which the component accessible through a maintenance opening is located. The internal section preferably comprises essentially the section of the housing interior located below the maintenance cover. In particular, this section extends perpendicularly to an inner wall of the maintenance cover towards the housing interior.

[0008] The housing has at least a first housing part and a second housing part which are connected to each other in a housing closure position and separated from each other in a housing opening position, wherein the housing is in particular arranged such that in the housing closure position the maintenance cover can be moved from its closure position to its opening position.

[0009] The housing extends along an imaginary longitudinal axis A of the housing, to which a drive shaft of the electric power tool's drive is arranged inside the housing, parallel to that axis. The first housing part is preferably a first housing shell, in particular a housing half, which surrounds a first housing interior section that is open parallel to a plane E. The second housing part is a second housing shell, in particular a housing half, which surrounds a second housing interior section that is open parallel to the same plane E. The first and second housing shells are connected along this plane E in the housing closure position to jointly define a housing interior formed by the first and second housing interior sections. The longitudinal axis A runs parallel to the plane E and is, in particular, arranged within this plane E.

[0010] The housing extends along an imaginary longitudinal axis A, to which a drive shaft of the electric power tool's drive is arranged inside the housing, parallel to this axis. The housing has a first, closed end in which the opening for the power cable is located, and, in particular, a second end, preferably connectable to an output housing, through which the drive shaft can be guided. Preferably, the maintenance cover is positioned closer to one end of the housing, and especially closer to the first end, than to the center of the housing, relative to the length of the housing measured along the longitudinal axis A. In this way, only a peripheral area of ​​the housing's interior is exposed to the environment during maintenance.

[0011] The first housing end is formed by an end wall whose outer surface is at least partially perpendicular to the longitudinal axis A. The housing opening is located in the area of ​​the first housing end. In the closed position, the end wall is formed partially by the first housing part, the second housing part, and, in the closed position, partially by the maintenance cover. This provides particularly easy access to the power cord end for maintenance purposes. Preferably, the maintenance cover includes at least a portion, particularly half, of the housing opening for the power cord end. This allows the power cord to be easily removed from the housing opening when the maintenance cover is open. Preferably, the housing opening for the power cord end and the maintenance opening merge seamlessly when the maintenance opening is open.Preferably, the housing opening for the power cable is arranged in such a way that a power cable end arranged in the housing opening in the closed position of the maintenance cover can be removed from the housing opening in the open position of the maintenance cover.

[0012] In its closed position, the maintenance cover has an edge section and a corner section of the housing, each of which may have a rounded shape. The edge and corner sections provide convenient maintenance access to the internal section.

[0013] The maintenance cover is designed to fit snugly against the housing edge that forms the maintenance opening. This prevents contaminants from entering the housing interior when the maintenance opening is closed, creating a dirt-protected housing interior. This also improves the seal of the maintenance opening.

[0014] Preferably, the maintenance cover forms a wall section of the housing that has an outer surface, wherein, in the closed position of the maintenance cover, the wall section of the maintenance cover is arranged, in particular, at least partially flush with the outer surface of the housing. Preferably, the wall section has an inner surface on which, in particular, at least one projection is formed that forms a positive fit with a recess in the housing when the maintenance cover is in its closed position. The recess for forming the positive fit can be formed on a projection of the housing inside its housing, and / or on a structure that can be arranged inside the housing.

[0015] Preferably, the maintenance cover is designed to be completely separable from the housing.

[0016] The housing has a connecting device for attaching the maintenance cover to the housing. The maintenance cover has at least two through holes, each of which can accommodate a screw for securing the maintenance cover to the housing.

[0017] Preferably, the maintenance cover is connected to the housing in its open position, in particular by means of a connecting device which may include in particular a hinge or a movable connecting element, in particular a cable, a strap or a film.

[0018] Preferably, the maintenance cover and / or the housing and / or a housing part is essentially formed from or comprises at least one injection-molded part.

[0019] Preferably, the outer surface area of ​​the maintenance cover occupies less than a fraction f of the outer surface area of ​​the housing, where f is selected from the group of preferred values ​​{0.25; 0.2; 0.15; 0.1; 0.05; 0.04; 0.03; 0.02; 0.01}. Preferably, the opening cross-section of the maintenance opening, which may in particular correspond substantially to the outer and / or inner surface area of ​​the maintenance cover, or the outer surface area or the inner surface area of ​​the maintenance cover, is smaller than a, where a is selected from the group of preferred values ​​{64 cm², 49 cm², 36 cm², 25 cm², 16 cm², 9 cm², 4 cm²}.

[0020] The invention relates to an electric hand tool, in particular an angle grinder, with a housing that surrounds an interior housing in which drive electronics for controlling a drive located inside the housing for driving a tool holder of the electric hand tool can be arranged. At least one serviceable component of the electric hand tool can be arranged or is arranged in an interior section of the housing. The housing has a maintenance opening adjacent to the interior section and a maintenance cover that closes the maintenance opening in a closed position and releases it in an open position. This allows access to the at least one serviceable component in the interior section, in particular for replacement.The at least one component to be serviced can, as claimed herein, be a power cable end, and / or in particular its lines running into the interior of the housing, and / or in particular the line contacts.

[0021] The invention relates to an electric hand tool, in particular an angle grinder, and especially an EC mains-powered angle grinder, with a housing according to the invention, comprising drive electronics arranged inside the housing for controlling a drive arranged inside the housing for driving a tool holder. Preferably, the tool holder is arranged on a tool shaft coupled to the drive, and a tool can be detachably mounted on the tool holder. The electric hand tool includes a mains cable for supplying power to the drive electronics, wherein preferably the end of the mains cable extends through the housing opening into the interior section of the housing and / or wherein preferably its conductors are connected to conductor contacts arranged in the interior section. The drive is in particular a brushless drive comprising a brushless motor.

[0022] The invention also relates to a method for manufacturing the housing according to the invention, in particular according to one or more of the described optional and advantageous embodiments, comprising the steps: Injection molding of the housing, which has the housing opening and the maintenance opening, in particular injection molding of a first housing part and injection molding of a second housing part, injection molding of the maintenance cover.

[0023] The invention also relates to a method for manufacturing the inventive electric hand tool, in particular the angle grinder, comprising the following steps: Providing the housing according to the invention; connecting the maintenance cover to the housing to close the maintenance opening.

[0024] Further preferred embodiments of the electric hand tool, in particular the angle grinder, will become apparent from the following description of the exemplary embodiment according to the figures. Reference numerals generally denote identical parts.

[0025] The figures show: Fig. 1 shows the perspective view of an electric hand tool equipped with the housing according to the preferred embodiment of the invention. Fig. 2 shows a top view of the electric hand tool machine of the Fig. 1 . Fig. 3 shows, in top view, an exploded view of the electric hand tool of the Fig. 1 , in which the two halves of the housing according to the invention and also the maintenance cover are detached from the electric hand tool. Fig. 4a bis 4d Each of the following is shown in perspective view in detail: the first end of the housing of the electric hand tool. Fig. 1 , in the open position of the maintenance cover. Fig. 5a shows a side view of the first housing end, here the first housing half, of the electric hand tool. Fig. 1 . Fig. 5b shows a side view of the first housing end, here the second housing half, of the electric hand tool. Fig. 1 . Fig. 6a und 6b Each image shows, in perspective view, the maintenance cover, in particular its inside, of the electric hand tool. Fig. 1 .

[0026] The figures each show an exemplary embodiment of an electric hand tool 1, here an angle grinder 1, which is equipped with a housing 20 according to an exemplary embodiment according to the invention.

[0027] In Fig. 3 The housing opening position is shown in which the first housing half 21 and the second housing half 22 are separated from each other by loosening the connecting element (not shown) for joining the housing halves, in this case screws. This allows a view of the components inside the housing.

[0028] Inside the housing is an electric drive 5, here implemented as a brushless EC mains electric motor 5, whose drive shaft (not shown) is arranged concentrically to the longitudinal axis A for rotation about it. The drive shaft extends into the output housing 6, which closes the open second housing end 26b and contains a gear head. The tool shaft, serving as the output and coupled to the drive shaft via a gearbox (not shown), is arranged perpendicular to the longitudinal axis A and is mounted to rotate about this perpendicular direction. The tool 8, here a grinding wheel 8 partially covered by a protective hood 8a, is detachably mounted on the tool shaft or tool holder.

[0029] A handle 9 is mounted on the output housing 6, the housing 20 itself also serves to handle the electric hand tool and can serve as an additional handle.

[0030] Inside the housing, adjacent to the closed first housing end 26a of the housing 20, the drive electronics 4 are arranged in the form of a circuit board 4, in particular attached to the inside of the housing. Electronic components are arranged on the circuit board 4, in particular parts of the power supply electronics are arranged on the side of the circuit board facing the first housing end 26a, furthermore IGBT components as components of the drive circuit, motor switches to supply power to the brushless EC mains electric drive, a rectifier, a capacitor, microcontroller, drivers, sensors, LED, and the power path of the power stage and motor.

[0031] The electronic components of this drive electronics 4 are all ultimately supplied with voltage via the power cable 10, which is transformed to the output voltages required by the drive electronics components. The power cable 10, or rather its visible end 10, is two-pole and contains two conductors (not shown) that emerge from the power cable sheath, which leads into the interior of the housing, and are guided through an internal section of the housing located at the first housing end 26a, in order to terminate in the conductor contacts 15, in which the copper conductors of the conductors are contacted by terminals of the conductor contacts 15.

[0032] The housing 20 has an opening 27, which in the housing closure position is formed by two recesses in the first housing half 21 and the second housing half 22. An actuating element 28, which is slidable in the direction of axis A towards the output housing, enters into this opening and serves as a start / stop switch for operating the angle grinder. The actuating movement is transmitted to a switch mounted on the circuit board by means of the switching rod 29, which runs axially in direction A inside the housing.

[0033] The power cable supplying the drive electronics, or more precisely, its end 10, penetrates through the housing opening 23 into the interior section of the housing where the line contacts 15 are located. The power cable end 10 is surrounded by an elastic sleeve 11, which serves as a strain relief and which, together with the power cable end 10, enters the interior section through the housing opening 23. Two conductors (not shown) emerge from the end of the power cable 10, their copper conductors connected by clamps to the terminal contacts of the two line contacts 15. As will be explained later, the housing opening 23, which is circular in cross-section in this example, is formed in the housing closure position by a first, semicircular recess in the first housing half 21 and a second, semicircular recess in the maintenance cover 50.

[0034] The geometric design of the first housing half 21 and the second housing half 22 is essentially such that the two housing halves 21, 22 exhibit almost mirror symmetry with respect to the plane E, which runs through the longitudinal axis A and parallel to the opening 21a of the first housing half 21 and the opening 22a of the second housing half 22. However, the second housing half 22 differs from the first housing half 21 in that the second housing half 22 – in the open position of the maintenance cover 50 – has a maintenance opening 31, or, in the case of the second housing half 22 – in the closed position of the maintenance cover 50 – a maintenance cover 50, which is separable from the rest of the housing half 22 and closes the maintenance opening, is arranged on the second housing half 22. The maintenance cover 50 includes a portion, here essentially half, of the housing opening 23 for the power cable end 10.

[0035] The interior subsection 30 is a section of the housing interior that is located in Fig. 3 The interior section 30 is marked with a dashed frame 30. The interior section 30 can be defined, in particular, as the section of the housing interior in which—with the angle grinder 1 mounted—the power cable end 10, and especially a strain relief 11, runs inside the housing, and in which the line contacts 15 for connecting the power cable wires are arranged. In this embodiment, the interior section 30 is arranged essentially within the section of the housing interior surrounded by the second housing half 22. The interior section 30 can extend slightly into the first housing half 21 from the housing half 22 in which it is arranged. Fig. 3 The first section of the housing interior extends in the first housing half 21 to level E, to which the second section of the housing interior in the second housing half 22 connects in the housing closure position.

[0036] The housing 20, in particular the second housing half 22, has the maintenance opening 31 adjacent to the interior section 30, and in particular a maintenance cover 50 which is in a closed position, as shown in Fig. 1 shown, the maintenance opening 31 is closed and placed in an open position, as shown in Fig. 2 The maintenance cover 50 is shown to allow manual access to the line contacts 15 that can be arranged in the interior section. It is designed to be completely detachable from the housing and is fastened by means of screws. The fastening means that receive the screws can be arranged on either the first housing half 21 or the second housing half 22.

[0037] A first housing end 26a of the housing 20 is formed by an end wall 32, the outer surface of which is at least partially perpendicular to the longitudinal axis A, and in which the housing opening 23 is arranged. In the housing closure position, the end wall 32 is formed partially by the first housing part 21 and the second housing part 22, wherein, in particular, the end wall 32 is formed partially by the maintenance cover 50 in the housing closure position (see figure). Fig. 1 . In the housing closure position, in which the maintenance cover 50 closes the interior section 30, the maintenance cover 50 is part of the housing part 22 and together with it forms the second housing half 22.

[0038] For example, in Fig. 4d As can be seen, when the maintenance opening 31 is open, the housing opening 23 and the maintenance opening 31 merge seamlessly into one another, meaning they are not separated by any components. This transition is designed in such a way that, when the maintenance opening is open, the power cable can be detached from the housing openings 23 and 31, and – after disconnecting the wires from the wire contacts 15 – the end of the power cable can be removed from the interior of the housing through the maintenance opening 31. This allows the power cable to be inspected and replaced even when the housing 20 is essentially closed overall, and only the maintenance opening 31 is open. This simplifies maintenance and prevents access to or damage to other interior sections or components, particularly those located outside the interior section 30 accessible through the maintenance opening 31.

[0039] As in Fig. 4a, 4b , 6a und 6b As can be clearly seen, the maintenance cover 50, in its closed position, forms an edge section 38 and a corner section 39 of the housing 20, each of which has a rounded shape. The maintenance cover 50 is designed to fit snugly against a housing edge 33 that forms the maintenance opening 31. Fig. 4b ) of the housing 20 or of the second housing part 22. For this purpose, the housing edge 33 has a stepped profile, at least in sections, which is complementary to the stepped profile, at least in sections, of the cover edge 53 ( Fig. 6a ) of the maintenance cover 50. By means of screws 59, which are secured by complementary screw bushings 55 ( Fig 4d ) on the maintenance cover 50 in through holes 55a, 56a ( Fig 5b ) grasp, the maintenance cover 50 is secured in the closed position. The threads 55b, 56b for securing the pins 59 are located on both the first housing part 21 and the second housing part 22.

[0040] The housing 20, 21 has openings 37 for air exchange between the inside of the housing and the environment ( Fig. 5a, 5b ).

[0041] The maintenance cover 50 forms part of the housing 20, which has an outer surface. In the closed position of the maintenance cover 50, the outer surface of the maintenance cover 50 is flush with the outer surface of the housing 20.

[0042] Fig. 6a Figure 1 shows the inner side 54 of the wall section 50, on which a total of three projecting sections 55, 56, 57 are formed. The projecting sections 55, 56, 57 are designed such that they form a positive-locking connection with preferably complementary raised sections in the closed position of the maintenance cover 50. The raised sections can be arranged on an inner side of the housing, on the first and / or the second housing part 21 / 22. The positive-locking connection can be in the form of a tongue and groove, a pin and bore, or a combination of both.

[0043] The housing has a connecting device with which the maintenance cover 50 can be connected to the housing 20. The connecting device includes two through holes 55a, 56a for receiving a screw 59 ( Fig. 6a ), at least one thread 55b, 56b formed in the housing 20 for receiving the screw and at least one screw 57.

[0044] The maintenance cover 50, the first 21 and second 22 housing part, which are formed in particular as housing halves, are each formed as one injection molded part.

[0045] The maintenance cover 50 is designed to be very compact. Its outer surface area is less than a fraction f of the outer surface area of ​​the housing, where f is, for example, 0.02. The cross-sectional area of ​​the maintenance opening 31 and the outer surface area of ​​the maintenance cover 50 are both smaller than a value a, where a is approximately 9 cm².

[0046] The maintenance cover 50 is sufficiently large to allow inspection of the power cable end 10, the strain relief 11, and the cable contacts 15, particularly inside the housing, and, if necessary, to enable maintenance or replacement of these components 10, 11, and 15. However, the maintenance cover can also be made as small as possible to minimize the internal section exposed to the environment during maintenance. A large portion of the housing interior, especially most of the drive electronics or all of the drive electronics (excluding the cable contacts 15), and the entire drive 5 remain protected by the housing 20 even when the maintenance cover is open. In the rarer case that maintenance of the drive electronics or the drive is required, the housing can also be opened by first removing the maintenance cover 50 and then separating the first 21 and second 22 housing sections, which are connected by screws. Reference symbol list

[0047] 1 Electric hand tool, in particular angle grinder 4 Drive electronics, circuit board 5 Drive, in particular brushless EC mains electric motor 6 Output housing 8 Tool 8a Protective guard 9 Handle 10 Mains cable, mains cable end 11 Bend protection sleeve 15 Line contacts 20 Housing 21 First housing part, first housing half 21a Opening of the first housing half 22 Second housing part, second housing half 22a Opening of the second housing half 23 Housing opening for 10 26a First housing end 26b Second housing end 27 Opening for 28 28 Switch 29 Switch rod 30 Interior section 31 Maintenance opening 32 End wall of the housing 33 Housing edge of the maintenance opening 37 Ventilation openings of the housing 38 Edge section of the housing 39 Corner section of the housing 50 Maintenance cover 53 Cover edge of the maintenance cover 54 Inside 55 Projection section, screw bushing 55a Through hole 55b Thread 56 Projection section, screw bushing 56a Through hole 56b Thread 57 Projection section 59 Screw Longitudinal axis, plane

Claims

1. Electric hand-held machine tool (1) with a housing (20), with drive electronics (4) arranged in the interior of the housing for controlling a drive (5) arranged in the interior of the housing for driving a tool holder, and with a power cord (10) serving to supply voltage to the drive electronics, whose power cord end extends through a housing opening (23) of the housing (20) into an interior part section (30) of the interior of the housing and whose lines are connected to line contacts (15) arranged in the interior section, the housing extending along an imaginary longitudinal axis (A), parallel to which a drive shaft of the drive (5) of the electric hand machine tool (1) is arranged in the interior of the housing, the housing (20) comprising a first closed housing end (26a) in which the housing opening (23) for the power cord (10) is arranged and which is formed by an end wall (32), the outer surface of which extends at least partially perpendicular to the longitudinal axis (A) and in which the housing opening (23) is arranged,and wherein the housing comprises at least a first housing part (21) and a second housing part (22) which are connected to one another in a housing closure position and are separated from one another in a housing opening position , characterized in that the housing (20) comprises a maintenance opening (31) adjoining the interior part section (30) and a maintenance cover (50) which closes the maintenance opening (31) in a closed position and opens it in an open position in order to enable manual access to the line contacts (15) which can be arranged in the interior part section (30), wherein the housing (20) is arranged such that in the housing closure position the maintenance cover (50) can be transferred from its closure position to its opening position, wherein the end wall (32) in the housing closure position is formed proportionally by the first housing part (21) and the second housing part (22) , and wherein the end wall (32) in the housing closure position is formed proportionally by the maintenance cover (50), so that the maintenance cover (50) in its closure position forms a edge portion (38) and a corner portion (39) of the housing (20) , wherein the maintenance cover (50) is configured for form-fit contact with an housing edge (33) forming the maintenance opening (31), wherein the housing edge (33) comprises an at least sectionally stepped course which is complementary to an at least sectionally stepped course of a cover edge (53) of the maintenance cover (50) wherein the maintenance cover (50) comprises through-holes (55a, 56a) for fastening and wherein threads (55b, 56b) for fastening screws (59), which engage through the through-holes (55a, 56a), are arranged both on the first housing part (21) and on the second housing part (22).

2. Electric hand-held machine tool (1) according to claim 1, wherein the first housing part (21) is a first housing shell (21) surrounding a first housing interior portion opened parallel to a plane (E), and wherein the second housing part (22) is a second housing shell (22) surrounding a second housing interior portion opened parallel to the same plane (E), which is open parallel to the same plane (E), wherein the first (21) and second (22) housing shells are connected along said plane (E) in the housing closure position to jointly define a interior of the housing formed of the first and second housing interior portions, and wherein said longitudinal axis (A) is parallel to said plane (E).

3. Electric hand-held machine tool (1) according to any one of the preceding claims, wherein the maintenance cover (50) comprises at least a part of the housing opening (23) for the power cord end (10).

4. Electric hand-held machine tool (1) according to one of the preceding claims, wherein the housing opening (23) and the maintenance opening (31) merge into each other when the maintenance opening (31) is open.

5. Electric hand-held machine tool (1) according to one of the preceding claims, wherein the housing opening (23) for the power cord (10) is arranged such that a power cord end (10) arranged in the housing opening (23) in the closed position of the maintenance cover (50) can be removed from the housing opening (23) in the open position of the maintenance cover (50).

6. Electric hand-held machine tool (1) according to one of the preceding claims, wherein the maintenance cover (50) is configured for form-fit abutment against the housing edge (33) forming the maintenance opening (30).

7. Electric hand-held machine tool (1) according to one of the preceding claims, wherein the maintenance cover (50) forms a wall piece of the housing, which comprises an outer side which is arranged in alignment with the outer side of the housing in the closed position of the maintenance cover, and the wall piece comprises an inner side (54), with which the maintenance cover is supported in its closed position on an inner side of the housing, on a projection section of the housing in its interior, or on a structure which can be arranged in the interior of the housing.

8. Electric hand-held machine tool (1) according to one of the preceding claims, wherein the maintenance cover (50) is configured to be completely separable from the housing (20).

9. Electric hand-held machine tool (1) according to one of the preceding claims, wherein the maintenance cover (50) and / or the housing (20) are substantially each formed from at least one injection-molded part.