PRE-ClampING DEVICE FOR A CIRCUIT BOARD

Description

[0001] The present invention relates to a control device for a machine tool comprising at least one circuit board, a thermal conducting element, a cooling device for cooling the at least one circuit board and at least one housing element, wherein in an assembled state of the control device the circuit board and the thermal conducting element are arranged between the cooling device and the housing element and wherein the thermal conducting element is positioned between the circuit board and the cooling device.

[0002] Control devices for machine tools are largely known from the prior art. The control device serves to control or regulate the functions of the machine tool, such as the speed of the drive (e.g., electric motor) of the machine tool. The control device can also be referred to as a control and regulating device or regulating device.

[0003] The development of heat can be problematic in the control device, as excessively high temperatures inside the control device can lead to damage to individual components of the control device and / or to a total failure of the machine tool.

[0004] Various cooling devices are already largely known from the prior art. The design and construction of control devices with such cooling devices, and in particular the connection of heat-generating components, such as circuit boards with capacitors, coils, or other components, to the cooling devices, is often complex, costly, and insufficiently efficient. A control device according to the preamble of claim 1 is already known from US 2014 / 254100.

[0005] The object of the present invention is therefore to provide a control device for a machine tool comprising at least one circuit board, a thermal conducting element, a cooling device for cooling the at least one circuit board and at least one housing element, wherein in an assembled state of the control device the circuit board and the thermal conducting element are arranged between the cooling device and the housing element and wherein the thermal conducting element is positioned between the circuit board and the cooling device, which solves at least the aforementioned problems.

[0006] The problem is solved in each case by the subject matter of independent claim 1.

[0007] Further advantageous embodiments of the invention can be found in the corresponding dependent claims.

[0008] The problem is solved in particular by a control device for a machine tool comprising at least one circuit board, a thermal conducting element, a cooling device for cooling the at least one circuit board and at least one housing element, wherein in an assembled state of the control device the circuit board and the thermal conducting element are arranged between the cooling device and the housing element and wherein the thermal conducting element is positioned between the circuit board and the cooling device.

[0009] According to the invention, a preloading device is included between the housing element and the circuit board to press the at least one circuit board in a predetermined direction against the heat-conducting element. This achieves a better thermal connection between the heat-generating circuit board and the cooling device, thus improving the overall cooling of the control device.

[0010] The heat-conducting element can be made at least partially of metal or a metal alloy. It is possible for the heat-conducting element to be made at least partially of copper.

[0011] The control device can also be referred to as a control and regulation device or as a regulation device.

[0012] According to the invention, the preloading device comprises at least a first spring element and a second spring element.

[0013] The first and second spring elements have different shapes and designs. The first spring element can have a larger volume or dimensions than the second. Due to these different designs, the preloading device can exert varying degrees of force or pressure on the circuit board and the heat-conducting element at different points.

[0014] According to the invention, the first spring element has a first extension in a predetermined direction and the second spring element has a second extension in the predetermined direction.

[0015] This allows the first spring element to exert a different force or pressure at a specific position on the circuit board or heat-conducting element than the second spring element. In other words, the spring elements of different heights can exert correspondingly different contact forces or pressures. The extension of the spring elements can also be described as their height or height.

[0016] According to an advantageous embodiment of the present invention, the preloading device may be at least partially made of an elastic material. This gives the preloading device a spring-like function. Furthermore, the use of the elastic material allows the preloading device to be positioned more easily and, above all, more flexibly within the control device.

[0017] According to an alternative embodiment, the pre-tensioning device may contain a mat. The mat serves to connect the spring elements to one another.

[0018] According to an advantageous embodiment of the present invention, it is possible for the pre-tensioning device to be at least partially made of silicone. This allows for flexible adaptation of the pre-tensioning device within the control device.

[0019] Further advantages will become apparent from the following description of the figures. The figures illustrate various embodiments of the present invention. The figures, the description, and the claims contain numerous features in combination. It will be advantageous for those skilled in the art to also consider the features individually and combine them into meaningful further combinations.

[0020] They show: Figure 1 is a side view of a machine tool with a control device according to a first embodiment; Figure 2 is a perspective view of the components of the control device according to a second embodiment, comprising a cooling device, a first housing element, a heat-conducting element, a first circuit board, a preloading device, a second circuit board, and a second housing element; Figure 3 is a perspective view of the preloading device with a number of first and second spring elements; and Figure 4 is a detailed view of the control device according to the first embodiment. Examples of implementation:

[0021] In Figure 1A machine tool 1 in the form of a hammer drill is shown. The machine tool 1, designed as a hammer drill, essentially comprises a housing 2, a drive 3, a percussion mechanism 4, a tool holder 5, a power supply 6, and a control device 7.

[0022] The drive 3 can be designed as an electric motor. The electric motor drive 3 generates torque, which is transmitted via a gearbox 8 to the impact mechanism 4. The impact mechanism 4 generates pulsed impacts that can be transferred by means of the tool holder 5 to a tool 9 held in the tool holder. The drive 3, the gearbox 8, and the impact mechanism 4 are all located inside the housing 2.

[0023] Alternatively, the machine tool 1 can also be designed as a saw, grinder or the like instead of a hammer drill.

[0024] The housing 2 has a front end 2a, a rear end 2b, a top end 2c, and a bottom end 2d. A handle 10 is positioned at the rear end 2b of the housing 2. The handle 10 is used to hold and guide the machine tool 1. Opposite, at the front end 2a of the housing 2, the tool holder 5 is positioned. The tool holder 5 is used to receive and hold the tool 5. If the machine tool 1 is configured as a rotary hammer, the tool 9 is configured as a drill bit or chisel.

[0025] Power supply 6 serves to supply machine tool 1 with electrical energy. As in Figure 1The power supply 6 is indicated as being designed as a battery. The battery 6 can be detachably connected to the lower end 2d or rear end 2b of the housing 2 via an interface 11. Alternatively, the power supply 6 can also be designed as a power supply unit instead of a battery, with which the machine tool 1 can be detachably connected to a wall socket.

[0026] In Figure 1 and 4 The control device 7 is shown according to a first embodiment. Figure 2 shows the control device 7 according to a second embodiment.

[0027] The control device 7 is essentially positioned at the rear and lower end 2b, 2d of the housing 2 and serves to control and regulate the various functions of the machine tool 1. One of these functions is, for example, the speed of the drive 3, which is designed as an electric motor. According to the first embodiment, the control device 7 comprises a cooling device 12, a housing element 13, a heat-conducting element 14, a circuit board 15, and a preloading device 16, cf. Figure 1 and 4 .

[0028] According to the second embodiment, the control device 7 comprises a cooling device 12, a first housing element 13, a heat conducting element 14, a first circuit board 15, a preloading device 16, a second circuit board 17 and a second housing element 18, cf. Figure 2 The first housing element 13 is a lower housing element in direction B. The second housing element 18 is an upper housing element in direction A.

[0029] As in the Figures 1 and 4 It can be seen that the first (and only) housing element 13 of the first embodiment of the control device 7 is the housing element located at the bottom in the direction of B.

[0030] The cooling device 12 is essentially designed in the form of a base plate 12a with protruding cooling elements 12b. The cooling elements 12b are designed as cooling fins. The cooling fins can also be referred to as cooling fins. With the help of the cooling device 12, the transfer of heat generated in the interior of the control device 7 to the environment and thus the actual cooling can be achieved. As shown in Figure 2 The cooling device 12 can be seen arranged behind or next to ventilation openings 19 of the housing 2 of the machine tool 1. Air can flow through the ventilation openings 19 into the interior of the housing 2 of the machine tool 1 and along the cooling elements 19, which are designed as cooling fins.

[0031] As in Figure 2 The second housing element 18 is shown in the form of a lid. A recess 20 is provided on the upper side of the first housing element 18, over which the cooling element 12b is attached.

[0032] The heat-conducting element 14 is designed in the form of a flat mat made of a thermally conductive material. The thermally conductive material is copper. The heat-conducting element 14 is positioned in direction B below the second housing element 18, which is designed as a cup.

[0033] The first board 15 is designed as a power circuit board and is positioned in direction B under the heat conducting element 14. As shown in particular in Figure 2The first circuit board 15 consists of the actual carrier board 21 and a number of electrical or electronic components 22. These components 22 can be, for example, capacitors, inductors, transistors, or the like. The carrier board 21 has a first side 21a and a second side 21b. These components 22 are attached to the first side 21a of the circuit board. No components are attached to the second side 21b, so that the second side 21b is essentially flat. The first circuit board 15 is positioned in the control device 7 such that the first side 21a of the carrier board 21, with the components 22, faces direction B, and the second (flat) side 21b of the carrier board 21 faces direction A.

[0034] The pre-tensioning device 16 is designed in the form of an elastic mat with a number of spring elements 23. In Figure 3An exemplary embodiment of the preloading device 16 is shown, in which thirteen spring elements 23 in the form of small triangular protrusions 23a and three spring elements 23 in the form of large cylindrical protrusions 23b are positioned on a mat 23c. Between the individual spring elements 23, webs 23d in the form of elongated protrusions are present. Alternatively, there can be more or fewer than three large and thirteen small spring elements 23. The number, shape, and position of the large and small protrusions depend on the number, shape, and position of the electrical or electronic components 22 on the first circuit board 15. The smaller a component 22 is on the first circuit board 15, i.e., the shorter a component 22 extends in direction B from the first side 21a of the circuit board 15, the larger the spring element 23 on the preloading device 16, i.e., the further the spring element 23, designed as a protrusion, extends in direction A from the mat.

[0035] The preloading device 16 serves to exert force or pressure on the first circuit board 15, so that, in an assembled state of the control device 7, the first circuit board 15 is pressed in direction A toward the heat-conducting element 14 and the cooling device 12. Within a linear range, the more strongly the heat-generating circuit board 15 is pressed in direction A toward the heat-conducting element 14 and the cooling device 12, the better the heat transfer from the first circuit board 15 to the cooling device 12.

[0036] The first housing element 13 is designed in the form of a relatively flat cover. The first housing element 13, designed as a cover, serves to receive the two circuit boards 15, 17 and the preloading device 16 arranged between the two circuit boards 15, 17. The first circuit board 15, the second circuit board 17, the preloading device 16, the heat-conducting element 14 and the cooling device 12 are thus positioned between the two housing elements 13, 18.

[0037] As already mentioned, according to the first embodiment of the control device 7, the upper housing element 18 can be omitted.

[0038] For assembly or joining of the control device 7 according to the first embodiment, the cooling device 12 is screwed to the lower housing element 18, designed as a cover, so that a gap is created between the cooling device 12 and the housing element 13. The heat-conducting element 14, the circuit board 15, and the preloading device 16 are positioned in the gap, see. Figure 1 and 4 .

[0039] In contrast, for assembly or joining of the control device 7 according to the second embodiment, the cooling device 12 is screwed to the first housing element 18, designed as a cup. The first (upper) housing element 13 is in turn screwed to the second (lower) housing element 18, designed as a cover, by means of screws 24. Again, a gap is created between the first (upper) housing element 13 and the second (lower) housing element 18, in which gap the heat-conducting element 14, the first circuit board 15, the pretensioning device 16, and the second circuit board 17 are positioned, cf. Figure 2 . Reference symbol:

[0040] 1 Machine tool 2 Housing 2 Front end of housing 2 Rear end of housing 2 Upper end of housing 2 Lower end of housing 3 Drive 4 Impact mechanism 5 Tool holder 6 Power supply 7 Control device 8 Gearbox 9 Tool 10 Handle 11 Interface 12 Cooling device 12a Base plate 12b Cooling element 13 First housing element 14 Heat conducting element 15 First circuit board 16 Preloading device 17 Second circuit board 18 Second housing element 19 Ventilation openings 20 Recess 21 Carrier plate 21a First side of the carrier plate 21b Second side of the carrier plate 22 Component 23 Spring element 23a Small triangular protrusion 23b Large cylindrical protrusion 23c Mat 23d Web 24 Screw

Claims

1. Control apparatus (7) for a power tool (1) containing at least one circuit board (15), a heat-conducting element (14), a cooling device (12) for cooling the at least one circuit board (15), and at least one housing element (13), wherein, in a mounted state of the control apparatus (7), the circuit board (15) and the heat-conducting element (14) are arranged between the cooling device (12) and the housing element (13), and wherein the heat-conducting element (14) is positioned between the circuit board (15) and the cooling device (12), wherein a preload device (16) is included between the housing element (13) and the at least one circuit board (15) in order to press the circuit board (15) against the heat-conducting element (14) in a predetermined direction (A), wherein the preload device (16) comprises at least one first spring element (23a) and one second spring element (23b), characterized in that the first spring element (23a) has a first extent in a direction (A) and the second spring element (23b) has a second extent in the direction (A) and therefore has a different height.

2. Control apparatus (7) according to Claim 1, characterized in that the preload device (16) is configured at least partially from a resilient material.

3. Control apparatus (7) according to at least one of Claims 1 to 2, characterized in that the preload device (16) is configured at least partially from silicone.