Title of Invention

"ELECTRIC MOTOR INTENDED FOR FIXING ON A PRINTED CIRCUIT BOARD"

Abstract

An electric motor intended for fixing on a printed circuit board, having a rotor and a stator, which has a plurality of coils and stator laminations,the stator laminations extending from the coils to the rotor, wherein the motor has contact springs (4,9), which are respectively connected in an electrically conducting fashion to a winding end (6) of the coils (1,8), and wherein the contact springs (4,9)., are configured in such a way that they bear against electric conductors (33) of the printed circuit board (28) under resilient biasing after the electric motor has been fastened to the printed circuit board (28).

Full Text

1A Description The invention relates to an electric motor intended for fixing on a printed circuit board, having a rotor and a stator which has a plurality of coils and stator laminations, the stator laminations extending from the coils to the rotor. There are known from the prior art electric motors, in particular as measuring elements in motor vehicle indicators, in which the coil ends of the electric motors are connected in an electrically conducting fashion to pins which are connected in an electrically conducting fashion to a printed circuit board using through-hole mounting, for example by means of wave soldering. Also known from the prior art is an electric motor in which the coils can be connected with the ends of their windings to electric conductors of a printed circuit board by soldering using surface mounting technology, the winding ends being wound around electrically non-conducting fork-shaped formations of the coil former of the respective coil. The complicated production of the electric connection between the coil and the printed circuit board is disadvantageous here. It is therefore the object of the invention to specify an electric motor which can be connected simply in an electrically conducting fashion to a printed circuit board without through-hole mounting. This object is achieved by virtue of the fact that the motor has contact springs, which are respectively - 2 - connected in an electrically conducting fashion to an end of the coils, and that the contact springs are configured in such a way that they bear against electric conductors of the printed circuit board under biasing citer the electric motor has been fixed = to the printed circuit board. Owing to this pressure of the contact springs on electric conductors of the printed circuit board, it is possible given an appropriate corrosion-resistant material of the surfaces of the contact springs such as, for example, tin, gold or platinum, to dispense with an additional soldering operation. The configuration of the motor is particularly simule when the contact springs are fixed on the coils. A housing which has openings for the contact sprincs through which the contact springs project from the housing on the cne hand protects the motor against external influences and, furthermore, simplifies the mounting and permits direct mounting of the contact springs on the coils. If the contact springs are configured in such a way that they are supported below the housing after the motor has been mounted on the printed circuit board, there is, furthermore, a saving of space on the printed circuit board. Moreover, the housing can then be fashioned such that after the motor has been mounted on ' the printed circuit beard the printed circuit beard completely covers the openings and the housing is thus-closed. Thus, the mechanical and electrical components of the motor are better protected against the action of heat, in particular, in the case, for example, of surface mounting of other components on "he printed circuit board which is required after mounting. - 3 -By configuring the contact springe in such a way that they are supported in the side of the housing after the motor has been mounted on the printed circuit board, it is possible for the contact springs additionally to be soldered to conductors of the printed circuit board by surface mounting when special requirements are placed on the durability of the electric connection. The opening in the housing can be fashioned in this case such that the housing largely protects the motor, with the result that the action of heat, for example, owing to a reflow soldering operation, does not damage the motor. The motor can be fixed particularly simply and quickly on the printed circuit board with the aid of one or more locating pins. This fixed is even more stable when one or more of the locating pins can respectively be spread by a spreading member which can be inserted into the interior of the respective locating pin. The durability of the connection described above can be increased further when the spreading member can be latched tight in the locating pin and can therefore also not leave its position in the case of all conceivable instances of shaking or vibrations. Simple mounting results for the contact springs when the coils in each case , have a coil former and the contact springs are-fixed on or in the coil former. The mounting can be carried out in a particularly simple fashion when the coil former is configured as an injection molded part and the contact springs are encapsulated with parts of the coil former by injection molding. A permanent electric connection between the coil windings and the contact springs can be produced by - 4 - fixing the ends of the coil windings on the contact springs in an electrically conducting fashion, for example by soldering or welding, and then cranking the contact springs at these ends in such a way that the coil ends are relieved. A compact design of the electric motor can be achieved by virtue of the fact that the stator laminations form a stator which has in the centre an opening for holding the rotor, the individual stator laminations being arranged around the opening. The motor is rendered particularly compact when it has four stator laminations and two coils. By virtue of the fact that two mutually opposed stator laminations are cranked simply relative to one another in such a way that parts of the stator laminations between which the first coil is arranged in a magnetically coupled fashion are aligned parallel to one another, the two other stator laminations have a first crank in the vicinity of the opening, and a second crank in the vicinity of the free ends, and the second coil is magnetically coupled between the free ends, it is possible to achieve that the coils can be arranged in parallel at the same level and can therefore be of identical configuration. When the stator laminations are magnetically coupled to the openings, they can be produced together in one piece from one sheet. The motor is particularly easy to drive when the stator laminations are interconnected at the opening via a non-magnetic metal. The coils can be magnetically coupled quickly, permanently and effectively to the stator laminations - 5 -by welding coil cores of the coils to the stator laminations. The invention is explained in more detail below with the aid of figures for particularly preferred exemplary embodiments. In the drawing, Figure 1 shows the view of a particularly preferred embodiment of a coil of the electric motor according to the invention. Figure 2 shows the view of a second particularly preferred embodiment of a coil of the electric motor according to the invention, Figure 2 shows the perspective view of a particularly preferred exemplary embodiment of the stator laminations of the electric motor according to the invention. Figure 4 shows the perspective view and the partial section of a stator comprising coils from Figure 1 which are inserted into stator laminations from Figure 3, in cooperation with a particularly preferred rotor. Figure 5 shows a plan view of a particularly preferred housing lower part of an electric motor according to the invention, for holding the stator and rotor, for example from Figure 4, and Figure 6 shows the view and the partial section of a particularly preferred motor on the partial view of a printed circuit board. The exemplary embodiment in Figure I of a particularly preferred coil 1 has a coil winding 2, a coil former 3, - 6 - two contact springs 4 and a coil core 5. The coil winding 2 is wound onto the injection molded coil former 3 in which parts of the contact springs 4 are encapsulated by injection molding with the material of the coil former 3, and are thus fixed. Winding endings 6 of the coil winding 2 are respectively connected in an electrically conducting fashion to one end of a contact spring 4, for example by soldering or welding. After connecting, the appropriate end of the contact spring 4 is, as represented, cranked or bent upward, in order to relieve the end of the coil winding 2. The contact springs 4 are produced from a strip spring material and entered by roughly 165° approximately in the middle, as may be seen from Figure 1. At its other end, the contact spring 4 has a bump 7 with which an electric conductor on a printed circuit board is intended to make contact. The embodiment described above is provided for making contact below the housing when used in the case of an electric motor with a housing. The coil 8 represented in Figure 2 differs from the coil 1 represented in Figure 1 in that its contact spring 9 is bent only by roughly 45° approximately in its middle. Otherwise, its remaining components of coil winding 2, coil former 3, coil core 5 and winding end £ corrospond to coil 1 in Figure 1. The coil 8 io provided for making contact on the side of the housing in the case of use with an electric motor having a housing. The use of the two coils 1, 6 described above is also possible in the case of a motor without a housing. Visible in Figure 3 ara four stator laminations 10, 11, 12 or 13 which form with their one end 10a, 11a, 12a, 13a an opening 14 for holding a rotor, and are magnetically coupled to the opening 14. The stator laminations 10, 11, 12, 13 are bent in such a way that in each case two stator laminations 10, 11 and 12, 13 - 7 -are located parallel to one another with in each case one end 10b, l1b and 12b, 13b for the purpose of holding the coils 1 and 8, respectively, represented in Figure 1 and Figure 2, respectively. In order to achieve this shape, the stator laminations 10, 11 respectively have a crank 10c, l1c and the stator laminations 12, 13 respectively have two cranks 12c 12d, 13c, 13d. One coil 1 each is respectively arranged in Figure 4 between two ends 10b, l1b and 12b, 13b of the stator laminations 10, 11, 12, 13. The coil cores 5 (not visible in Figure 4) are preferably welded to the stator laminations 10, 11, 12, 13 in the region of the ends 10b, l1b, 12b, 13b. This effects a stable, quick connection in cimultancous conjunction with passing on the magnetic flux efficiently. The connection between the otator laminations 10, 11, 12, 13 and the coils 1 can, however, also be performed by other connecting techniques such as, for example, screwing or riveting. Also to be seen in Figure 4 is a rotor comprising a diametrically magnetized disk 15 which is largely Arranged in the opening 14 and connected to a shaft 16 in a fashion fixed in terms of rotation. A worm (not represented) which cooperates with a worm wheel 17 represented in Figure 6 is preferably arranged on the shaft 16. The bearing of the shaft 16 is likewise not represented in Figure 4. When current is passed through the two coils 1, they generate a magnetic flux which is conducted via the atratcr laminationc 10, ll, l0 , 13 and exertc a force on the diametrically magnetized disk 15. Thus, the electric- motor can be oprated as a stepping motor, for example, when direct current is applied to the coils one after another or else simultaneously. By driving the two coils 1 with sinusoidal currents offset by 90°, it is also possible to operate the motor as a synchronous motor in which the speed of the shaft 16 - 8 -corresponds to the frequency of the sinusoidal currents. In Figure 5, a housing lower part 18 has two flat troughs 19, 20, four openings in the form of longitudinal slots; 21, shaft bearings 22, 23, a worm wheel shaft hearing 24 locating ring 25 with spreading members 26 and a locating clip 27. The flat troughs 19, 20 are configured in such a way 'that the stator lamination 11 can be supported in the trough 19, and the stator lamination 13 can be supported in the trough 20, and so the stator comprising stator laminations 10, 11, 12, 13 and coils 1, can assume a predetermined position in the housing lower part 18. In this arrangomont, the eontact cpringc 4 thou project out of the housing lower part through the longitudinal slots 21. The shaft 16 from Figure 4 can be borne in the shaft bearings 22, 23, and then assumes the correct position in the stator described in Figures 3 and 4. The spreading members 26 are connected to the locating pin 25 via webs 26a. In Figure 6, a stator is inserted into a housing comprising a housing lower part 18 and housing upper part 30. The stator differs from the stator described in Figures 3 and 4 only in that the stator laminations 10, 11, 12, 13 are not coupled magnetically in the region of the opening 14, but are interconnected via a ring 2 9 made from non-magnetic material, for example brass. This connection can be produced, for example, by projection welding of the stator laminations 10, 11, 12, 13 in a ring 29. Via the shaft 16 (not represented in Figure 6) and the worm (likewise not represented in . Figure 6) arranged on the shaft 16, the diametrically magnetized disk 15 is connected to the worm wheel 17, which is connected on both sides in the axial direction to a worm wheel shaft 31. The worm wheel shaft 31 is mounted in the housing lower part 16 in the worm wheel - 9 -shaft bearing 24 (see Figure 5) and in the housing upper part 30 in a bearing which i s not represented. The housing upper part 30 rests on the housing lower part 18, and is retained via locating clips of which the locating clip 27 is represented in Figure 6. The locating pins 25 are fashioned to be rotationally symmetrical, and are connected to the remaining housing lower part 18 via webs 25a. The locating pins 25 are split into arms 25b by axially running slots 25c. The locating pins 25 can be plugged through round holes 32 of the printed circuit board 2 8 through the slots 2 5c and the Lettering ends 25d, the diameter of the round holes 32 being smaller than the diameter of the locating pin 25 in the unloaded state represented in Figure 6. Owing to the elasticity of the locating pin 25 or insertion of the spreading member 26 in the locating pin 25, the locating pin assumes is original shape, with the result that the motor is fixed on the printed circuit board 28. The webs 26a (see Figure 5) of the spreading member 26 are designed such that they break in the event of a pressure from above on the spreading member 26. The spreading member 26 can then be inserted into the locating pin 2 5 by further pressure from above on the spreading member 26. The motor is pressed in this way against the printed circuit board 2 6 with the underside of its housing lower part 18. At the same time, the contact springs 4 (not represented in Figure 6) are pressed onto th© printed circuit board 30 and electrically connected to electric conductors 33 located on the printed circuit board 28. A pointer of an indicator, for example a tachometer or revolutions counter, or a clock can be mounted on the worm wheel shaft 31. - 10-WE CLAIM: 1. An electric motor intended for fixing on a printed circuit board, having a rotor and a stator, which has a plurality of coils and stator laminations./the stator laminations extending from the coils to the rotor, wherein the motor has contact springs (4,9), which are respectively connected in an electrically conducting fashion to a winding end (6) of the coils (1,8), and wherein the contact springs (4,9), are configured in such a way that they bear against electric conductors (33) of the printed circuit board (28) under resilient biasing after the electric motor has been fastened to the printed circuit board (28). 2. The electric motor as claimed In claim 1, wherein the contact springs (4,9), are fixed on the coils (1,8). 3. The electric motor as claimed in claim 1 or 2, wherein the electric motor has a housing (18) in which openings (21) are formed through which the contact springs (4,9) project from the housing. 4. The electric motor as claimed in claim 3, wherein the contact springs (4) are configured in such a way that they are supported below the housing (18) after the motor has been mounted on the printed circuit board (28). 5. The electric motor as claimed in claim 3, wherein the contact springs (8) are configured in such a way that they are supported in the side of the - 11 -housing (18) after the motor has been mounted on the printed circuit board (28) . 6. The electric motor as claimed in one of the preceding claims, wherein the electric motor has one or more locating pins (25) with the aid of which it can be latched tight in cutouts in the printed circuit board (28). 7. The electric motor as claimed in claim 6, wherein the locating pin or pins (25) can be spread in each case by a spreading member (26) which can be inserted into the interior of the locating pin (25) . 8. The electric motor as claimed in claim 7, wherein the spreading member (26) can be latched tight in the locating pin (25). 9. The electric motor as claimed in one of the preceding claims, wherein the coils (l, 8) have a coil former. (3) , and wherein the contact springs (4, 9) are fixed in or on the coil former (3) . 10. The electric motor as claimed in claim 9, wherein the coil former (3) is injection molded, and the contact springs (4f 9) are encapsulated with parts of the coil former (3) by injection molding. 11. The electric motor as claimed in claim 9 or 10, wherein the winding ends (6) of the ceil windings (2) are respectively fixed in tin electrically conducting fashion on one end of a contact spring (4, 9), and wherein the contact springs (4, 9) are cranked at this end. .2. The electric motor as claimed in one of the preceding claims, wherein the stator laminations - 12 -(10, 11, 12, 13) form a stator which has in the centre an opening (14) for holding the rotor (15), the individual stator laminations (10, 11, 12, 13) being arranged around the opening (14). 13. The electric motor ,as claimed in claim 12, wherein in each case two opposed stator laminations (10, 11, 12, 13) are arranged relative to one another such chat they hold a coil (1, 8). 14. The electric motor as claimed in claim 13, wherein the electric motor has four stator laminations (10, 11, 12, 13) and two coils (1, 8). 15. The electric motor as claimed in claim 14, wherein two mutually opposed stator laminations (10, 11) are cranked simply relative to one another in such a way that parts of the stator laminations (10b, l1b) between which the first coil (1, 8) is arranged in a magnetically coupled fashion are aligned parallel to one another. 16. The electric motor as claimed in claim 15, wherein the two other mutually opposed stator laminations (12, 13) have a first crank (12c, 13c) in the vicinity of the opening (14), and a second crank (12d, 13d) in the vicinity of the free ends (12b, 13b), and the second coil (1, 6) is arranged in a magnetically coupled fashion between the free ends. 17. The electric motor as claimed in one of claims 12 to 16,wherein . the stator laminations (10, 11, 12, 13) are magnetically coupled at the opening (14). 18. The electric motor as claimed in one of claims 12 to 16, wherein the stator laminations (10, 11, 12, - 13 -13) are interconnected at the opening (14) via a non-magnetic metal (29). 19. The electric motor as claimed in one of the preceding claims, wherein the coils (1, 8) each have a coil core (5) which is welded to the stator laminations (10, 11, 12, 13). An electric motor intended for fixing on a printed circuit board, having a rotor and a stator, which has a plurality of coils and stator laminations,the stator laminations extending from the coils to the rotor, wherein the motor has contact springs (4,9), which are respectively connected in an electrically conducting fashion to a winding end (6) of the coils (1,8), and wherein the contact springs (4,9)., are configured in such a way that they bear against electric conductors (33) of the printed circuit board (28) under resilient biasing after the electric motor has been fastened to the printed circuit board (28).

Documents:

00980-cal-1999-abstract.pdf

00980-cal-1999-claims.pdf

00980-cal-1999-correspondence.pdf

00980-cal-1999-description(complete).pdf

00980-cal-1999-drawings.pdf

00980-cal-1999-form-1.pdf

00980-cal-1999-form-18.pdf

00980-cal-1999-form-3.pdf

00980-cal-1999-form-5.pdf

00980-cal-1999-letters patent.pdf

00980-cal-1999-p.a.pdf

00980-cal-1999-priority document others.pdf

00980-cal-1999-priority document.pdf

980-CAL-1999-ASSIGNMENT.pdf

980-CAL-1999-CORRESPONDENCE 1.1.pdf

980-CAL-1999-CORRESPONDENCE 1.2.pdf

980-CAL-1999-FORM 27.pdf