Abstract:
In order to connect a pump (1) with an electric motor (2) quickly and form-fittingly, a hollow, tappet-shaped stud (6) is formed onto the pot-shaped motor housing (7), specifically onto the bottom of the pot (10). The stud engages an insertion recess (5) of the pump. A driving eccentric (4) of the driven shaft (3) is connected with the pump during the assembly of the pump. If the inside of the tappet-shaped stud (6) is to receive the first motor bearing, a fit is needed at the inside as well as at the outside of the stud. If the motor housing (7) is made from deep drawn sheet metal, the double fit is only possible, if, when viewed in the circumferential direction, the cross section of the wall of the stud (6) is formed like a wave. This facilitates the use of a plastic cover (18) in connection with the sheet metal housing (7) and the avoidance of a carbon brush support plate. In connection with a further embodiment, the lack of a support plate facilitates an automatic assembly of the motor (2) as well as the combination with plug connections and electronic housings.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to an electric motor connected with a pump. The housing of the pump has a cylindrical insertion recess which receives a tappet-shaped stud of the motor housing. The stud encloses the first bearing of the motor armature free from play. The recess is situated at the side of the pump and provides an aperture for the armature shaft. 
     Units including a pump and an electric motor are known. A specific field of use for such units is in the brake system of a motor vehicle and, especially, in the anti-locking-system for the brakes of a motor vehicle. Typically, the pump is a radial piston liquid pump which is driven by an eccentric on the driven shaft of an electric motor. According to the prior art, a motor housing made from sheet metal is used. The motor housing is equipped with an aluminium flange which receives the bearing and has to be treated accordingly. In addition, a separate carbon brush support plate is necessary. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to provide a motor housing in which a form-fitting connection to the pump, and to the assembly of the bearing situated at the side of the pump free from play, is achieved without additional treatment of the housing. This object is achieved according to the present invention by providing, in a conventional unit including an electric motor and a pump driven by the electric motor, a particular structural relationship between the housing of the motor and the cover closing it. The bottom of the pot-shaped housing is provided with a bulge, which forms the stud receiving the first bearing and which can form-fittingly be inserted into the recess of the pump housing. 
     The present invention renders it possible to form a motor housing with a tappet-shaped stud as a deep drawn member. The tappet-shaped stud facilitates a form-fitting centering, without additional treatment, both outside and inside the stud. The first bearing, situated at the side of the pump, can be pressed into the inside of the tappet-shaped stud. In addition, to connect the motor with the pump, the tappet-shaped stud is form-fitted to the recess of the pump housing. The cross section of the wall in the section of the motor housing which forms the tappet-shaped stud is selected to provide the elasticity and stability which is necessary for the outer and inner centering and the safe connection as well as to fix the first bearing and the pump. 
     In order to ensure support of the pump housing at the motor housing outside of the tappet-shaped stud, the present invention provides, at the bottom of the pot of the housing, a ring-shaped bead concentrically surrounding the stud. The bead has integral fixing eyes arranged approximately diametrically opposite each other and the whole embossed part forms a flat flange plane for the pump housing. The pump housing is situated directly on the flange plane, which is perpendicular to the longitudinal axis of the armature. Pressure nuts are placed into the fixing eyes when assembling the motor and the pump. It is also possible to put screw threads directly in the motor housing. 
     The outer surface of the bottom of the pot may be recessed slightly with respect to the flange surface. A groove in the bottom of the pot makes the use of a relatively big radius possible at the transition from the bottom of the pot to the stud. The groove forms a circumferential channel, together with the part of the motor housing turned towards the pump housing and the flat flange surface, which, if necessary, can remove leakage liquid. 
     In a preferred embodiment of the invention, a runoff for leakage fluid is provided. During operation, the leakage fluid runs down through the space between the ends of the C-shaped legs of the ring-shaped bead. The ends of the C-shaped legs point down and the bottom of the groove and the bottom of the drain channel are preferably situated in the same vertical plane. 
     The configuration of the tappet-shaped stud is advantageous in facilitating removal of leakage fluid because it creates axial channels in which the liquid can flow. Thus, an impenetrable connection of this stud with the recess of the pump is avoided. In case the pump is leaky, the overflowing hydraulic oil can flow through the channels. The channels are formed by the flutes of the wave-like circumference of the stud and the recess of the pump housing and are in connection with the circumferential groove of the pump housing. A further advantage is that the bottom of the pot of the motor housing is integrally made with the cover of the motor housing and the stud, so that there are no sealing problems in this area. If impermeability is especially required, the stud is preferably round in the first third of its length, adjacent to the bottom of the pot, so that a seal can be put around the stud in this area. 
     If the second bearing of the motor is formed like a ball, the first recess in the cover has a corresponding shape where it surrounds the bearing. The pipe-shaped second recess of the cover is preferably closed to the outside. 
     A support ring is situated between the second bearing and the commutator of the armature. The support ring may have an axially protruding edge facing the commutator on which the commutator can be put during assembly. Because it closes the inner mouths of the radial channels of the cover, if the cover is loose, the support ring retains the carbon brushes which are under spring pressure in the radial channels. The support ring is moved to the side during the assembly of the motor and the commutator moves in front of the inner mouths of the radial channels. Thus, the carbon brushes abut against the commutator once released by the support ring. 
     Therefore, the support ring is ideal for an automatic blind assembly of this motor. The support ring preferably protrudes slightly, when viewed in a radial direction, at least in the area of the inner mouths of the channels, so that the commutator has a smaller distance from those inner mouths after the assembly. The carbon brushes can, depending upon the size of this space, be moved radially after being released by the support ring, until they meet the commutator. This structural relationship and the fact that the cover is preferably made from heat-resistant plastic (and, therefore, all necessary additional components can be attached), renders unnecessary a separate brush support plate. This and the easier assembly lead to simplification and cheaper manufacture of this motor. 
     In another embodiment of the present invention, the support ring forms an axial support member for the armature at the side of the commutator in the end position of the shift. The support ring is held in its end position of the shift by a press fit in the second recess of the cover. An armature, mounted in the motor pot by a bearing bush, can support itself either directly or indirectly by putting a ring or the like in between the armature and the pot. 
     A sensor is helpful to monitor use of the motor and pump. If the cover is plastic, it is possible to form a rail-like stud integrally onto the cover. The sensor is mounted on the stud and no additional assembly work is needed. 
     The sensor has a coil body punched out of a flat metal sheet member. The flat metal sheet member is provided with two integrally made first connecting tabs for attaching the sensor and two second connecting tabs for the electrical connection with the two coil ends. This formation of the coil body makes a series production possible, by punching the coil bodies out of a metal blank using the cycle method. As far as changes in shape are necessary, it is possible to make them immediately or in the same cycle method or with a following tool. 
     The coil cannot be fixed directly to the metal member. Rather, the section of the punched metal sheet member, which receives the coil, is equipped with a plastic coating from which the first and second connecting tabs are omitted. This coating is fitted to the sheet-metal member in such a way that the wire cannot be damaged when winding the coil and that an electric contact with the coil body is reliably precluded. There is only an electric connection at the second connecting tabs, one of which is electrically connected with one wire end of the coil and the other with the other end of the coil. Those connections can be secured by solder, for example. 
     It is possible to use an injection molded plastic for the plastic coating. The plastic is folded around the area of the coil body which has to be electrically insulated. The plastic member is easily folded and fixed on the coil body, because it is formed as two substantially identical halves with a connecting web. Folding the plastic member is especially easy if the thickness of the wall between the two folding axes is smaller than the thickness of the remainder of the wall and the component is shortened in the area of the folding axes (when viewed in the longitudinal direction). 
     One half of the plastic member is provided with a spaced edge at least in the area of the winding. The height of the spaced edge approximately corresponds to the thickness of the metal sheet of the coil body. Thus electrical security is increased. Each half of the plastic member is H-shaped, whereby the web of the &#34;H&#34; receives the coil. This shape facilitates the manufacture of the coil. 
     If the coil body is a single sheet metal member, at which both connections for the sensor and also both connections for the two coil ends are fixed, the sensor and coil end connections must be electrically separated. The metal member is formed of two differently sized pieces connected by two webs. The two webs, which cause the mechanical connection of the two pieces of the metal member, are separately removed during manufacture. The first web is punched out after the plastic coating is applied to the coil body; the second web is removed after an insulating coating is applied. 
     The sensor can be connected with an external monitor by providing a plug or the like, integrally formed in the cover. The connecting tabs of the sensor can also be used directly as plug contacts. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is described more clearly by way of the drawings, in which: 
     FIG. 1 is a longitudinal section of the motor with a pump schematically indicated, 
     FIG. 2 is the lateral view and partial longitudinal section of the motor on a reduced scale, 
     FIG. 3 is a side view of the left end of the motor of FIG. 2, 
     FIG. 4 is a side view of the right end of the motor, 
     FIG. 5 is a detailed view of the motor housing in the area of the tappet-shaped stud illustrated on a highly enlarged scale, 
     FIG. 6 is a longitudinal section of the support ring of the motor, 
     FIG. 7 is a front view of the support ring, 
     FIG. 8 is a lateral view of the support ring, 
     FIG. 9 is a top view of a sheet metal blank with two punched coil bodies arranged one behind the other, 
     FIG. 10 is a partial section taken in the longitudinal direction of the coil body, 
     FIG. 11 is a top view of the coil body with the plastic coating and coil, 
     FIG. 12 is a lateral view of FIG. 11 in the longitudinal direction, 
     FIG. 13 is a view of FIG. 11 in cross direction, 
     FIG. 14 is a top view of the plastic coating which is spread out in a plane, 
     FIG. 15 is a lateral view of FIG. 14, 
     FIG. 16 is a top view of the finished sensor, and 
     FIG. 17 is a lateral view of the sensor. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in FIG. 1, the electric motor 2 is form-fittingly connected with the pump 1 via a plug connection. The eccentric tappet 4, which is fixed and formed on the free end of the driven shaft 3, can engage the pump, which is preferably formed as a radial piston pump, as required. The pump 1 has a conventional insertion recess 5 to receive a hollow tappet-shaped stud 6 of the motor housing 7. The first bearing 8 of the motor armature 9 is inside of this stud 6. 
     To ensure simultaneously an inner fitting for the first bearing 8 and an outer fitting for the tappet-shaped stud 6 in the insertion recess 5, the tappet-shaped stud 6 is formed in a specific way. This makes it possible to manufacture the motor housing 7 together with the tappet-shaped stud 6 as a single deep drawn member. 
     As is evident from FIG. 1 or 2 viewed in connection with FIG. 4, the cross section of the wall of the hollow, tappet-shaped stud 6, which protrudes beyond the bottom of the pot 10 in the axial direction, is made wave-like or is provided with longitudinal flutes 11. This shape of the stud 6 ensures (1) a tight and form-fitting connection between pump 1 and electric motor 2, and (2) a concentric, form-fitting assembly of the first bearing 8, which can withstand the consequent strain, in the inside of the hollow, tappet-shaped stud 6. 
     A disc 13 may be placed between the first bearing 8, which is formed as a rolling bearing, and the bottom 12 of the pot-shaped stud 6. A penetration bore 14 is provided in stud 6 for the driven shaft 3. The axial fixation of driven shaft 3 is provided on the other side of first bearing 8 by a pipe-shaped stud 15 of the motor armature 9. Furthermore, the second bearing 16 for the armature 9 or the driven shaft 3 of the motor 2 is situated in a first recess 17 of the cover 18. Cover 18 closes the pot opening 19 of the motor housing 7 which faces away from the pump 1. 
     Especially evident from FIG. 4 or 5, at the bottom of the pot 10 of the motor housing 7 there is a ring-shaped bead 20 approximately concentrically surrounding the stud 6 and protruding towards the outside. Bead 20 has integral fixing eyes 21 and 22 arranged approximately diametrically opposite each other. The surface of the pump 1 turned towards the bottom of the pot 10 meets this bead 20 directly. Conventional press nuts 24 and 25 are inserted into the respective bore of each fixing eye 21 and 22. The connection with the pump is made with the screws 23 in a known manner. 
     The plane surface of the bead 20, which extends vertically to the longitudinal axis 27 of the driven shaft 3, forms a flange surface 26. Bead 20, an embossed part, is essentially C-shaped (FIG. 4), whereby the space between the two C-leg ends forms a drain channel 28. In operational position, bead 20 is funnelled to the lower section of a groove 29 in the bottom of the pot 10 so that any leakage oil which might be in the groove 29 can completely flow off through the drain channel 28. The groove 29 is limited by the ring-shaped bead 20 at the outside and by the stud 6 at the inside, whereby the bottom of the groove 29 as well as the bottom of the drain channel 28 are situated in the plane of the outer surface of the bottom of the pot 10. FIG. 4 shows that the inner circumferential line 30 of the embossed part or bead 20 approximately corresponds to the outer circumferential line 31 of the tappet-shaped stud 6 in the area of the bottom of the pot 10 and, therefore, the groove 29 has a corresponding shape when viewed in the circumferential direction. 
     FIGS. 4 and 5 show, in broken lines 29a, 29b, that the stud 6 can form a cylindrical section 90 which is adjacent to the bottom of the pot 10. The outer diameter of stud 6 corresponds to the outer diameter in the areas outside of the longitudinal flutes 11. A conventional O-ring 91 may be placed in the cylindrical section 90, around the stud 6, so that the O-ring 91 is squeezed between the motor housing 7 and a chamfer 92 of the pump. In this way the pump 1 is sealed towards the outside in the area of the stud 6. 
     The edge 32 of the pot 10 is bent to the outside, as shown in FIG. 1, to form a contact area for the cover 18. Two eyes 33 and 34 are formed in the edge 32 and make it possible to connect the motor housing 7 with the cover 18 by screws 35 and 36. 
     As already explained, the cover 18 has a first recess 17 for the second bearing 16. Recess 17 is situated at the inner end of the second pipe-like recess 37, provided for a support ring 38, and joins it in the axial direction. The support ring 38 is shown in detail in FIGS. 6 to 8 and, more generally, in FIG. 1. In FIG. 1, the assembly end position of the support ring 38 is illustrated. Support ring 38 is arranged between the second bearing 16 for the armature shaft 3 and the commutator 39 of the armature shaft 3. 
     In the initial position, not shown in the drawings, taken by the support ring 38 when the cover is loose, the support ring 38 covers the inner mouth 40 of two radial channels 41. Radial channels 41 are displaced in the circumferential direction (only one of the radial channels 41 can be seen in FIG. 1). Thus, support ring 38 holds down the carbon brush 43 which is under the effect of a load spring 42 in each radial channel 41. Since the commutator 39 is fixed without rotation or translation on the shaft 3 of the armature 9, the end of the support ring 38 engages the front of the commutator 39 through its support members 45 and 46. 
     At this point in time the support ring 38 is spaced axially from the second bearing 16. The more the cover 18 approaches the housing 7 of the motor 2, the more the support ring 38 is pushed into the second recess 37 and the more the left end of the armature shaft 3 (illustrated in FIG. 1) enters the second bearing 16. Since the commutator 39 always touches the support ring 38 during this shifting movement, the commutator 39 overlaps each inner mouth 40 of each radial channel 41 to that extent to which each inner mouth 40 is left uncovered by the support ring 38. The carbon brush 43 cannot make an uncontrolled movement in its radial channel 41. Rather, when completely released by the support ring 38, the carbon brush 43 will contact the commutator 39 after penetrating the small space between the inner mouth 40 and the commutator 39. 
     In the end position of the shift, the support ring 38 is held without play in the second recess 37. The support ring 38 also forms a support for the armature 9 by engaging the front face of the commutator 39. The armature 9 is mounted in the motor housing 7, free from play, via a calotte cap or cylindrical bearing in the motor housing. 
     When the unit consisting of the pump 1 and the electric motor 2 is used in a vehicle brake system, the function of the electric motor must be monitored. For this purpose, a sensor 48 is provided. Sensor 48 is situated at a rail-like stud 47 of the cover 18. If the cover 18 is made from plastic, as is preferable, the rail-like stud 47 can be molded as part of the cover 18. According to FIG. 1, the sensor 48 interfaces with the armature 9 of the electric motor 2. The different elements of the sensor 48 are illustrated in FIGS. 9 to 17. Discussed indirectly below are the different steps for manufacturing this sensor 48. 
     The sensor 48 has a coil body 49, which is punched out of a sheet metal band 50 (see FIG. 9). As shown in FIG. 9, the different coil bodies 49 are connected to the remainder 52 of the sheet metal band 50 by a web 51. 
     This web 51 is later removed. Two first connecting tabs 53 and 54 for the sensor 48 and two second connecting tabs 55 and 56 for the electric connection of the two coil ends 57 and 58 are formed directly onto the coil body 49. Whereas the first connecting tabs 53 and 54 remain in the plane of the metal sheet band 50, the second connecting tabs 55 and 56 are bent twice in opposite directions (FIG. 10). Thus, the coil ends 57 and 58 can be fixed in several windings 59 or 60 at their second connecting tabs 55 and 56 without problem. This connection is secured by means of solder or the like. 
     The area 62 of the coil body 49 which takes up the coil 61 is surrounded by a plastic coating, the exact shape of which is shown in FIGS. 14 and 15. The exact shape of the coil body 49 is shown in FIGS. 9 and 10. Especially from FIG. 13, but also from FIGS. 11 and 12, it can be seen how the plastic coating 63 surrounds the coil body 49 in its area 62. It can also be seen that this coating 63 covers neither the first connecting tabs 53 and 54 nor the second connecting tabs 55 and 56. 
     The plastic coating 63 consists of two halves 64 and 65 which are more or less the same, but which differ slightly in detail, as explained below. They are connected via an intermediate web 66. The connection of the web 66 with each of the plastic coating halves 64 and 65 produces folding axes 67 and 68. The distance between the two folding axes 67 and 68 corresponds approximately to the thickness of the sheet metal band 50 of the coil body 49. 
     Two hook-like locking members 70 and 71 are formed onto a first longitudinal edge 69 which runs parallel to the folding axes 67 and 68. When the plastic coating 63 is assembled onto the coil body 49, each of these hook-like locking members 70 and 71 overlaps a second longitudinal edge 72, which runs parallel to the first longitudinal edge 69. The half 64 of the plastic member 63 is, at least in the area of the winding of the coil 61, provided with a spaced edge 73 which corresponds to the circumference of the plastic member 63 in this area. The height of the spaced edge 73 corresponds to the thickness of the sheet metal band 50 of the coil body 49. Furthermore, as shown in FIG. 14, each half 64 and 65 of the plastic member 63 is H-shaped. The web 74 of each H-shaped half 64 and 65, respectively, receives the coil 61. 
     As illustrated in FIG. 9, the punched coil body 49 consists of two dissimilar (at least in size) pieces 75 and 76. FIG. 11 shows that the one of the two webs, namely web 78, is removed after the plastic coating 63 has been fixed on the coil 61. Thus a mechanical, but also an electrical, connection between the two pieces 75 and 76 is provided only via the web 77. 
     The unit, shown in FIG. 11, consisting of the coil body 49, its insulating plastic coating 63, and the coil 61 fixed thereon, is surrounded by a plastic insulating coating 79 in an additional manufacturing step. According to FIG. 16, only the first two connecting tabs 53 and 54 project beyond this coating 79. By tabs 53 and 54, the sensor 48 can be connected to a source of electricity. After applying the coating 79, there is enough stability so that web 77, between the two pieces 75 and 76 of the coil body 49, can be removed. FIG. 16 shows a punched out area 80. Connecting tabs 53 and 54 are each connected with a connecting line or wire 81 which leads to a plug 82 of the cover 18. This plug 82 also can be integrally formed with the cover 18. 
     In a manner not shown in these drawings, an electronic box or the like can be integrated into the cover 18 without any problem due to the materials used and to the method of manufacture. When injection-molding the coating 79, the web 77 has to be punched out and, therefore, the coating 79 has to be made thinner at this point or a respective recess in the coating 79 has to be provided.