DE1732978U - CRAFT MACHINE WITH ELECTRIC MOTOR DRIVE. - Google Patents

Description

ΡΑ541

Lr / Hl 5793

15 * 9 * 1952 '■

Attachment to

Patent application

■ ο "bs τ t B osch"& mbH » _s '. Stuttgart, Breitsoheidstrasss 4

with electric motor drive

Until the invention relates to a hand machine tool with an electric drive motor ₉ which is housed insulated in a metallic outer housing. In the case of hand-held power tools with metallic housing parts that are directly accessible to contact, which can be directly connected to high voltages of more than 43 ToIt, there is a risk that the operating voltage will reach the metallic housing part ^ due to defective insulation of current-carrying ropes and lead to accidents. For this reason, it has long been common practice to manufacture individual housing parts that are "particularly at risk" or even the entire housing from insulating material. Such measures, however, are only appropriate for low-weight hand-held vacuum machines, since insulating material housings break easily even if they are too low ode ^ at least cracked,. ·

It has also been suggested for hand tool machines with a housing made of metal between the housing and the machine parts that are immediately under tension in the event of damage (Stand, anchor, etc.) To arrange construction parts made of insulating material.

The task on which this invention is based is _? To form and arrange such an insulating part in such a way? that on the one hand the motor as a whole insulates against the metallic outer casing.

Robert Bosch GmbH - 2 - Lr / El 5799

Stuttgart. '15c9 * 1952

on the other hand, however, the asial distance of the armature bearing as well as the mechanical see! Strength exclusively through the metallic outer housing is ensured.

A particularly expedient solution which meets the requirement of electrical insulation is fulfilled by mechanically weakly stressed insulating material, 'results according to the invention in that the isolation is achieved by two each for themselves in the metallic outer housing centered end shields "made of insulating material, at least one of which is cup-shaped and carries the stator of the motor,

F The invention and further details are described and explained in more detail below with reference to two exemplary embodiments shown in the drawing.

Fig. 1 shows one-in two mutually perpendicular cutting planes after; Line I-I in Fig. 2 guided longitudinal section by a hand drill,

Mg. 2 shows one ^; according to the line II-II in Fig * 1 - cross-section, but without motor armature »

Pig »5 shows another hand drill, also in an in two perpendicular to and mutually aligned longitudinal sections,

The hand drill essentially consists of an electric one Universal motor with. an anchor 11 and a stand 12, one Motor housing 15 made of cast aluminum., As well as one on the front Face of the motor housing, arranged handle 15 This loading

% is also made of metal. It contains a double-pole Heta switch 16 and an interference suppression capacitor 17 and also takes one end of the power cable 18. For complete electrical insulation of the motor and its metal parts (of the stator 12 and the entire armature 11) which are immediately under tension in the event of damage, a pot-shaped end shield 20 made of molded insulating material is arranged, which in its interior the motor [except for the shaft piece 21 protruding on the transmission side

■ completely covers. Deic cup-shaped end shield is only about the length of its outer circumference, over which the stator 12 fastened in it by screws 22 extends, including its field winding, in the cylindrical bore of the metallic outer

'<■ Robert Bosnh G-rifoH - 3 - Isr / Bl 5793 ί

Stuttgart. September 15, 1952 · "7

housing 13 fitted into the bottom part 27 of the topfxörsigen Jjager shield, stiffened by strong ribs 26, sits the outer ring 28 of a sugar bearing arranged in the "saw of the collector 30" diametrically arranged 'eyes 23 are provided. " each of which contains a guide bushing 24a and 240 to accommodate a grinding carbon. The guide bushings 24a and 24b are cut through a plug 29 made of insulating material, which has a narrow thread and with this in the Eyes 23 is screwed.

The ball bearing arranged on the transmission-side end of the armature shaft 21 with its outer ring 31 is also used as a bearing plate Serving · insulating piece 32 fitted into the aas metal housing 13 centered against the gear housing Η bottom wall 33 and is provided with a Sacklo0h.boh.rang 54 on the transmission side, which serves as a bearing point for the yoke shaft 36. Your second.

. This shaft is located in a blind hole bole 37 mounted in the gear housing 14 "which contains a lubrication groove 53 so that no voltage can be transmitted from the armature shaft 21 to the gear housing 14"

, 42 made of insulating material »

The design and arrangement of the cup-shaped end shield 20 itself deserves particular attention. "

This is lähe in άβτ its the collector-side ball bearing up ^£ receiving the base part 27 at its periphery with a flange ■ hand 52 is provided, which is inserted in a fitting 51 on the offenen.Stirnseite of the metal casing 13 and there through a housing in the handle 15 The incised counter surface 53 is clamped against the axial displacement. The distance D between the clamping surface 53 and the center of the ball bearing, which is approximately in the plane of the clamping surface, is very small and should not be more than 10 mm if possible

• Robert Bosch GmbH - 4 - · Lr / Rl 5799 Stuttgart ■ _; ·. 15.9 »1952

wear. This type of one-sided clamping of topfförmig'e'n camp there child 20 ₉ is achieved that its hollow cylindrical longitudinal, partly to stretch freely in the axial direction or disappear can without these changes in length to provide storage to the AnkeaS-wave, can be harmful . Only axial changes in length in the bottom part 27? d * $. Changes to from stand D ₅ can result in changes to the warehouse distance. As the distance B is kept very small, any changes in length can hardly affect the bearing distance «.

Any changes in the dimensions of the cup-shaped end shield 20 in radial sighting cannot affect the operational safety as a result of the construction of the insinanderge which can be seen from Pigur 2! the engine, a sheet metal section is used whose outer boundary line ^ Awei over approximately 90 ° includes extending diametrically opposed circular arcs, eieren Snd ~ '. points are connected by a straight line. The inner surface 'of the cup-shaped bearing plate 20 surrounding the Hotorstander 12 touches the motor stator, so only at two stubs (60 and 62), which together extend about half of the beginning \ can easily have an effect in the spaces opposite ... the straight boundary surfaces 61 and 63 of the motor stator ^ without excessive internal stresses occurring in the insulating material. ·

If the cup-shaped end shield 20 expands, for example due to the swelling of the insulating material, the recess 64 or 65? which run along the inner surface of the metal housing 13, absorb such expansions. These recesses are in assembling the flats 61 and .63 of the Motorständer3 disposed opposite _t - so that the cup-shaped housing 20 in these zones not applied and the motor stator 12 nor the metal housing 13 may follow due to the properties of the insulating material changes "

The described and illustrated arrangement and design of the insulating material results in a perfect solution for all conceivable operating cases safe protection against touch voltages, because even then, if, due to exceptional circumstances, the cup-shaped insulating end shield should break, the fragments are only slightly

äobert Bosch GmbH - 5 - Lr / Hl 5799 -

Stuttgart September 15, 1952

push! rönnen ^ but open; everybody prevent all? that the possibly Tenter metal parts of the motor which are at operating voltage, immediately come into contact with äea external rig housing.

The illustrated Eanawsrkzeugiaaschins in Figure "5 differs iron the previously described machine substantially me characterized _s that the pot-shaped end plate 80 on the Eitzelseite the motor armature 71 attached and equilateral the Srennwand Aryan the gear housing 74 and & ss motor housing 73 forms _B in the G-egonsats to after the machine! Pig * 1 and 2. is also the second here. " with 82 "designated end shield has a pot-shaped design. Like the front end shield, it is on a ring-shaped fire 83 ₉ which runs roughly in the same plane as the balls. 78 of the ball bearing accommodated in end shield 32 The chip surface with which it rests against the motor housing _s at least approximately in the plane of the angels 79 aes there -aufgenoiameiien ball bearings · With this arrangement , too, the changes in length that may occur in the cup-shaped bearing shapes can practically not affect the bearing spacing at all affect? since the bearing spacing is determined by the metallic motor housing 73, while the wall parts of the cup-shaped end shields can move at will along the cylindrical bore 85 of the motor housing 73 "during expansion or shrinking. taken in insulating bushes 93, which are not connected to the end shields 83 and 80, but from the outside! are fitted in the motor housing 73.

Claims (1)

flfue claims: 1 ») Hand tool base with electric drive motor» which is housed in an isolated metallic outer housing with the help of two? £ agersehilde of insulating material _t characterized in that the housing awischen to Srzielung a closed possible insulating the engine and the metallisciien outer housing is formed of one of the iageracMlde of insulating topff'drmig, LANS the stator of the motor over its entire £ ength umseiiliesst WL to at least the of the other storyteller's ireieiit » 2 ») HaHd-wörkzeugmasoiiinö nacii claim 1, daäarcii gekemizeiclinet that the pot Sraig» Bagersonild is at least approximately in the S "plane of the anchor bearing on the outer housing against axial 7erselaieliuag t estgespanat * 3 ») HandwerkzeugmascMiie after. To claim 1 and 2, characterized selehnet gekerm- ■ that the Ausaengehäuse divided two armature bearing transversely czar Anfceraonse in the plane of at least one of ", and that of the outer housing in the thus created! Erennfuge between & ^ n hone one of Lagersanilde at its gang is clamped » 4) Hand tool machine according to claim 3 * characterized by * that the bearing shield between the handle (15) serving and the cylindrical part connected to the transmission (14) (13) of the outer housing is clamped 5 ·) Hand machine tool according to claim 1, characterized in that » that one of the bearing shields is pressed in one piece, diametrically Opposite eyes (23) for receiving the collector brushes (25). -2- B 10 369 / gia Ga -2- Xv / Sä Ε.1γ 5799 Kotoert Bosch ß-iabH, Stgt. 3.9 »1956 β ·) Hand tools according to claim. 5 » characterized in that the eyes for receiving the brushes (25) on the cup-shaped bearing plate (20) are arranged in δ.βτ Habe of its bottom part (27), protrude through the outer housing and. a radial gap of 1 mm at their passageways. across from the Atissengeliäuse 7 ·} Handwerkseagmaseiiine after. ÄnsprnG & 1 »characterized by the fact that swiae & en the stator of the motor and the longitudinal part of the pot-shaped bearing cMldes Aiisaparangen are seMen> which altogether about half of the inner housing • sassaeiisn yxnä in a ^ daler höiung at least, uan · näliernd des Ständerfeleeirpaicets extend 8 ») HaaLdwörkseTzgiaascliine naöh Änspruoii 1 _r dadureh that <OCE stator of the motor attfgebaut of sheets is to use two iisram each having fOtev about 90 ° extending incisions» ^ fäkrend their swisehen these incisions extending itself. " Urar crack lines at least approximately circular arcs with essential gp ^ aseres Baüös siad # 9 ·} Appliance machine according to one of Claims 1-8, characterized in that that between the. Metal case and the wall of the üagersehiXdes recesses are provided »the extend axially at least approximately over the JtMgQ of the stator - * feleehpakets umä along the Ifantellinien deaf housing over those zones in which the motor stator is not directly on the inner and the top £ -shaped bearing shield. Io ·} handicraft brewing machine according to one of claims 1-9 «characterized > that the carbon brushes guided in the intermediate housing are covered on the outside by screw caps made of insulating material »which carry an external thread and with this, in a sewing boring screwed into the cup-shaped end shield are·