EP1871574B1 - Hand-held machine tool - Google Patents

Description

State of the art

The invention relates to a hand tool according to the preamble of claim 1. Such a power tool is disclosed in US5692574 , There are known power tool machines with a housing having a motor housing and a cup-shaped housing cover. The motor housing surrounds inner components, such as an electric motor, and the cup-shaped housing cover surrounds other electrical components, such as switches, power supply, etc. In the assembled state of the power tool, the cup-shaped housing cover is added in the axial direction of the housing cover to the motor housing. A seal of the housing is achieved in that the housing cover and the motor housing rest against each other without play. This is made possible by a corresponding design of the motor housing and the housing cover on the one hand and by the use of a press during assembly on the other.

Advantages of the invention

The invention relates to a hand tool with a motor housing and a housing cover, which is attached to the motor housing.

It is proposed that the power tool has an applied to the motor housing and the housing cover insulating means which is guided by a guide means in the direction of the motor housing and / or housing cover. With the Insulating can be insulated from the housing enclosed interior to the outside and it can effectively counteract the formation of an electrical bridge of eg metal and / or coal dust from the engine to a hand of the operator, whereby a high level of security for the operator can be achieved. Alternatively or additionally, the housing cover and the motor housing can be isolated from each other to minimize transmission of vibrations from the motor housing to the housing cover. As a result, a high level of comfort for the operator can be achieved. This vibration isolation, which can be achieved by the choice of design and / or the material of the insulating, is particularly suitable for use in, for example, grinding machine tools in which vibrations, for example due to imbalances of a rotating grinding wheel arise.

By the guide means, for example a stop element in the motor housing or in the housing cover, a displacement of the insulating means in the axial direction can be prevented, e.g. when the housing cover is pushed onto the motor housing. In this case, an undesired crushing of the insulating means between the motor housing and the housing cover and a resulting bad seal are prevented.

The insulating means is preferably made of an elastic material, such as an elastomer or a plastic, which is provided for vibration damping. Due to the possible sealing of the interior by the insulating means to the outside, a high assembly cost, eg the exact adaptation of the housing cover to the motor housing or the use of a Press, be bypassed. The motor housing may be the part of the housing in which a motor of the power tool, for example, during assembly, is used.

A high ease of use of the power tool can be achieved when the housing cover is cup-shaped and is attached in particular in the axial direction of the motor housing. An operator can guide the hand tool primarily on the housing cover and the housing cover can be well dampened against vibrations emitted by the engine and transmitted to the motor housing. The axial direction may be the axial direction of the cup-shaped housing cover. The insulating is guided in the axial direction. The housing cover may be one or more parts, with parts of a multi-part housing cover can be mounted laterally. The housing cover is preferably arranged on the side of the hand tool machine facing away from a tool.

Advantageously, the guide means is part of a stage in the motor housing or in the housing cover. With this embodiment of the invention, the insulating means can be applied to the guide means with little installation effort. In addition, assembly errors, such as unwanted crushing of the insulating in a running example as a groove guide means can be prevented.

It is also proposed that the insulating means is guided by the interaction of the motor housing and the housing cover in the radial and axial directions. Through this guide assembly errors can be avoided. Furthermore, the arrangement of the insulating means between the housing cover and the motor housing done in a compact manner by the design of the insulating means of the corresponding configuration of the motor housing and the housing cover is adjusted.

In a further embodiment of the invention, the insulating means has recesses. As a result, the insulating means, for example in the tangential direction, be positively connected to the motor housing and / or the housing cover, which prevents twisting of the insulating means during operation of the power tool.

Advantageously, the hand tool has internal elements which are arranged within the motor housing and / or the housing cover and engage in the recesses. Thus, the arrangement of the insulating means with the internal components of the hand tool, e.g. a carbon brush holder, done in a compact manner, since the insulating means is adapted to the configuration of these internal components.

Conveniently, the insulating material is integrally connected to the motor housing or the housing cover. It can be assembly errors and loss of the insulating, for example, during a repair, avoided. The material bond can be achieved by injecting the insulating means on the housing cover or on the motor housing or by gluing, soldering, welding or fusing.

In a further embodiment of the invention, it is proposed that the insulating means be manufactured with at least two outer surfaces aligned parallel to each other is, wherein in the mounted state at least one of these outer surfaces rests against the motor housing and the other outer surface on the housing cover. This embodiment of the insulating means is particularly suitable for the damping of the at least substantially vertically aligned vibrations to the outer surfaces, which are transmitted from the motor housing to the housing cover.

It is also proposed that the insulating means has at least one introduced in the axial direction recess. Efficient damping of both axially and radially aligned vibrations can be achieved since the insulating means has high flexibility in the axial direction. In addition, the recess can form an expansion space for expansion of the insulating means in the axial direction.

In a simple way, a complete seal of the motor housing and the housing cover can be achieved in that the insulating means closed annularly applied to the motor housing and the housing cover.

Advantageously, the insulating means is open annular on the motor housing and the housing cover and has a gap - in particular in the radial direction - on. Due to the interruption of the annular insulating means, a high elasticity of the insulating medium in the radial direction can be achieved, which allows the use of large material hardnesses, eg polyamide, in the production of the insulating agent.

In order to achieve a complete seal of the motor housing and the housing cover, the motor housing may have a rib which is arranged in the gap.

In an advantageous embodiment of the invention, the insulating means is biased in the radial direction attached to the motor housing or the housing cover. The insulating material is not loose on the motor housing or on the housing cover, but exerts on its own force a pressure in the radial direction of the motor housing or the housing cover. Thereby assembly errors and the loss of the insulating means, e.g. during a repair, to be avoided.

A further embodiment provides that the insulating means surrounds the housing cover or the motor housing L-shaped. By means of this form-fit adapted to an edge, during assembly of the hand-held power tool, e.g. in a sliding of the housing cover on the motor housing, a shearing of the insulating means are prevented from the edge.

It is also proposed a stop that prevents complete compression of the insulating. Thus, crushing of the insulating means disposed between the motor housing and the housing cover can be prevented, e.g. when the hand tool falls down and hits.

drawing

Further advantages emerge from the following description of the drawing. In the drawing are Embodiments of the invention shown. The drawing, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

Fig. 1

eine Schnittansicht eines Winkelschleifers mit einem Motorgehäuse, einem Gehäusedeckel und einem Isoliermittel,

Fig. 2a

einen vergrößerten Ausschnitt aus Fig. 1,

Fig. 2b

ein alternatives Isoliermittel,

Fig. 2c

ein weiteres Isoliermittel, das stoffschlüssig mit dem Motorgehäuse verbunden ist,

Fig. 2d

ein weiteres Isoliermittel,

Fig. 3

eine Explosionsansicht eines Teils eines Winkelschleifers mit einem Motorgehäuse, einem Gehäusedeckel und einem geschlossen ringförmigen Isoliermittel,

Fig. 4

eine Schnittansicht eines Abschnitts des Winkelschleifers aus Fig. 3 in montiertem Zustand und

Fig. 5

ein offen ringförmiges Isoliermittel.

Show it:

Fig. 1

a sectional view of an angle grinder with a motor housing, a housing cover and an insulating means,

Fig. 2a

an enlarged section Fig. 1 .

Fig. 2b

an alternative insulating agent,

Fig. 2c

a further insulating means, which is materially connected to the motor housing,

Fig. 2d

another insulating agent,

Fig. 3

an exploded view of a portion of an angle grinder with a motor housing, a housing cover and a closed annular insulating means,

Fig. 4

a sectional view of a portion of the angle grinder Fig. 3 in the assembled state and

Fig. 5

an open-ring insulating means.

Description of the embodiments

FIG. 1 shows a sectional view of an angle grinder 10a with a front part 12 and a rear part 14. The front part 12 has an output shaft 16 and a transmission housing 18, a the output shaft 16 with a Motor shaft 20 connecting and not shown in the figure gear comprises. To the output shaft 16 may be provided for grinding surfaces provided grinding wheel. The rear part 14 comprises a motor housing 22a, which engages around an electric motor 24, and a cup-shaped housing cover 26a attached to the motor housing 22a, with an axial direction 28 and a radial direction 30, which covers a switch 32 and a carbon brush holder 34. Through an opening 36 of the housing cover 26a, a power cable 38 is guided. The motor housing 22a and the housing cover 26a enclose an inner space 40a. In an arranged between the motor housing 22a and the housing cover 26a gap 42a an insulating means 44a is arranged, which rests closed closed ring on the motor housing 22a and the housing cover 26a. It isolates on the one hand the inner space 40a to the outside and on the other hand, the housing cover 26a of the motor housing 22a.

FIG. 2a shows an enlarged section II FIG. 1 , The motor housing 22a and the housing cover 26a have a step 46a and 48a, respectively. The insulating means 44a is guided by a guide means 50a in the motor housing 22a and a further guide means 52a in the housing cover 26a in the axial direction 28, which are each designed as a aligned in the radial direction 30 portion of the step 46a and 48a.

During operation of the angle grinder 10a, pulverized coal may form in the interior 40a. In addition, metallic grinding dust can surround the angle grinder 10a, be sucked by the engine ventilation in the interior 40a and settle there.

By means of the insulating means 44a insulating the inner space 40a in the region of the gap 42a, filling of the gap 42a by these dusts and a resulting electrical bridge from the electric motor 24 to a hand of the operator can be effectively prevented and security gained. In addition, an operator can be relieved of the vibrations in the axial direction 28 and the radial direction 30 transmitted from the motor housing 22a to the housing cover 26a by the insulating means 44a.

In assembling the angle grinder 10a, in a first step, the insulating means 44a, which may be made smaller in diameter than the diameter of the step 46a and then biased in the radial direction 30, is fitted onto the step 46a until it is annular on the guide means 50a is applied. In a second assembly step, the housing cover 26a is pushed in the axial direction 28 on the insulating means 44a, whereby the insulating means 44a annularly abuts against the guide means 52a. By the interaction of the guide means 50a and 52a, an undesirable pinching of the insulating means 44a between the motor housing 22a and the housing cover 26a and a resulting poor sealing of the inner space 40a can be avoided in the second assembly step.

FIG. 2b shows a section of an alternative angle grinder 10b, which comprises a motor housing 22b with a guide means 50b, a housing cover 26b with a guide means 52b and an insulating means 44b. The housing cover 26b and the motor housing 22b enclose an inner space 40b. The insulating means 44b surrounds the Housing cover 26b
L-shaped and can be molded onto it. As a result, a shearing off of the insulating means 44b by an edge of the housing cover 26b when the housing cover 26b is pushed onto the motor housing 22b can be prevented. Furthermore, the insulating means 44b is visible to an operator. Alternatively, the insulating means 44b may be configured so as to surround the motor housing 22b in an L shape. The insulating means 44b may be made with a smaller inner diameter than the diameter of the step 46b and exert a pressure on the motor housing 22b under its own power in the installed state, which allows a good sealing of the inner space 40b to the outside. Furthermore, the motor housing 22b and the housing cover 26b form a gap 53b, whose function in the description of Figure 2d given is.

Figure 2c shows a section of an alternative angle grinder 10c. The angle grinder 10c comprises a motor housing 22c with a guide means 50c, a housing cover 26c and an insulating means 44c, which is materially connected to the motor housing 22c. The material bond can be achieved by injecting the insulating means 44c to the motor housing 22c or by gluing or fusing. During assembly of the angle grinder 10c, the housing cover 26c is pushed onto the insulating means 44c until an end face 54 abuts against an edge 56 of the motor housing 22c. When disassembling the angle grinder 10c, for example, in a repair case, the insulating agent 44c remains by the material connection to the motor housing 22c fitting. Thereby, a loss of the insulating 44c and assembly errors in an assembly of the Angle grinder 10c can be prevented. Alternatively, the insulating means 44c may be materially connected to the housing cover 26c.

Figure 2d shows an alternative angle grinder 10d with a housing cover 26d, which comprises a guide means 52d, an insulating means 44d and a motor housing 22d, which has a guide means 50d and a stop 58 designed as a contact surface. The housing cover 26d and the motor housing 22d enclose an inner space 40d. The housing cover 26d is fixed to inner members 55d of the angle grinder 10d by a screw 57d screwed in a screw bearing 59d. The insulating means 44d is made with a first outer surface 60 and a second outer surface 62 aligned parallel to the first outer surface 60. In the mounted state of the angle grinder 10d, the outer surface 60 lies on the housing cover 26d and the outer surface 62 on the motor housing 22d. Furthermore, the insulating means 44d is provided with a plurality of recesses 64 introduced in the axial direction 28.

In operation of the angle grinder 10d, vibrations transmitted from the motor housing 22d to the housing cover 26d may be damped by the insulating means 44d. Vibrations which are oriented perpendicular to the outer surfaces 60 and 62 can be attenuated efficiently by a deformation of the insulating means 44d, since the insulating means 44d with the recesses 64 a deformation space in the axial direction 28 is available. By the recesses 64 also a high flexibility of the insulating means 44d is achieved in the axial direction 28, the one efficient damping of aligned in the axial direction 28 vibrations allows. The insulating means 44d, for example, closed annular abut the motor housing 22d and the housing cover 26d, which allows a good seal of the interior 40d, or have a plurality of separate segments, which provides additional space between the segments. Furthermore, vibrations transmitted from the inner members 55d via the screw bearing 59d and the screw 57d to the housing cover 26d can be damped by the choice of the material of the screw bearing 59d, eg, an elastic material. When a high pressure in the radial direction 30 is exerted on the housing cover 26d from the outside, for example when the angle grinder 10d falls down, the stop 58 designed as a contact surface prevents complete compression of the insulating means 44d since the housing cover 26d strikes the stop 58.

FIG. 3 11 shows an exploded view of a portion of an angle grinder 66 having a motor housing 68, a closed annular hard rubber-made insulating means 70a, and a cup-shaped housing cover 72 having an axial direction 74 and a radial direction 76 which, when assembled, surrounds inner members 78. The inner members 78 include a switch 80, a brush holder 82 and walls 84. The motor housing 68 has an outer surface 86 which forms a shoulder 88 with a shoulder. The insulating means 70a has a plurality of recesses 90a, in which the walls 84 engage in the assembled state of the angle grinder 66. The housing cover 72 has a plurality of guide means 92 formed as ribs on, which are arranged on an inner side 94 of the housing cover 72. The guide means 92 are offset behind an inner edge 96 of the housing cover 72 in the axial direction 74 and run through to the rear wall of the housing cover 72. Furthermore, the motor housing 68 and the housing cover 72 enclose an interior space 98 in the mounted state of the angle grinder 66.

When mounting the angle grinder 66, the insulating means 70a, which is produced with a larger outer diameter than the inner diameter of the inner side 94, biased in the radial direction 76 inserted into the housing cover 72 in a first assembly step. After insertion, it exerts a pressure on the housing cover 72 by its own power. In a second assembly step, the housing cover 72 is pushed with the insulating means 70 a used on the projection 88 until the insulating means 70 a abuts the end face of the projection 88 and is pushed by the latter in the axial direction 74 to the rear until it is performed on the guide means 92 as ribs is applied.

FIG. 4 shows a sectional view of a portion of the angle grinder 66 in the mounted state. The insulating means 70a abuts against the end face of the projection 88 and on the guide means 92. The arrangement of the insulating means 70a in the axial direction 74 behind the projection 88 allows a compact design in the radial direction 76. Due to the bias, the insulating means 70a remains in the housing cover 72 when the housing cover 72 is removed from the motor housing 68, for example in a repair case, causing a loss of the insulating material 70a and assembly error in an assembly of the angle grinder 66 can prevent.

FIG. 5 shows an alternative insulating means 70b, the recesses 90b and a gap 100 in the radial direction 76 and consists of a harder material, such as polyamide, as the insulating means 70a. Compared to the insulating means 70a, the insulating means 70b also has a high flexibility in the radial direction 76 through the gap 100. When mounting the angle grinder 66, as described for the insulating means 70a, a rib of the angle grinder 66, not shown in the figures, additionally engages into the gap 100. As a result, on the one hand, a high stability of the insulating means 70b in the mounted angle grinder 66 and, on the other hand, a good sealing of the interior 98 to the outside can be achieved.

Claims (12)

1. Hand-held machine tool having a motor housing (22a, 22b, 22c, 22d, 68), a housing cover (26a, 26b, 26c, 26d, 72), which is joined to the motor housing (22a, 22b, 22c, 22d, 68), and an insulating means (44a, 44b, 44c, 44d, 70a, 70b) which bears on the motor housing (22a, 22b, 22c, 22d, 68) and on the housing cover (26a, 26b, 26c, 26d, 72) and is guided in the direction towards the motor housing (22a, 22b, 22c, 22d, 68) and/or housing cover (26a, 26b, 26c, 26d, 72) by a guide means (50a, 50b, 50c, 50d, 52a, 52b, 52d, 92), where a displacement of the insulating means (44a, 44b, 44c, 44d, 70a, 70b) in the axial direction (28, 74) can be prevented by the guide means (50a, 50b, 50c, 50d, 52a, 52b, 52d, 92) when the housing cover (26a, 26b, 26c, 26d, 72) is pushed onto the motor housing (22a, 22b, 22c, 22d, 68), characterized in that the housing cover (26a, 26b, 26c, 26d, 72) is cup-shaped and is joined to the motor housing (22a, 22b, 22c, 22d, 68) in the axial direction (28, 74).
2. Hand-held machine tool according to Claim 1, characterized in that the guide means (50a, 50b, 52a) is part of a step (46a, 46b, 48a) in the motor housing (22a, 22b) or in the housing cover (26a).
3. Hand-held machine tool according to Claim 1 or 2, characterized in that the insulating means (70a, 70b) has cut-outs (90a, 90b).
4. Hand-held machine tool according to Claim 3, characterized by internal elements (78), which are arranged inside the motor housing (68) and/or the housing cover (72) and engage in the cut-outs (90a, 90b).
5. Hand-held machine tool according to one of the preceding claims, characterized in that the insulating means (44c) is integrally bonded to the motor housing (22c) and/or the housing cover (26c).
6. Hand-held machine tool according to one of the preceding claims, characterized in that the insulating means (44d) is produced with at least two outer surfaces (60, 62) that are aligned parallel to one another, wherein, when mounted, at least one of these outer surfaces (60, 62) bears on the motor housing (22d) and the other outer surface (60, 62) bears on the housing cover (26d).
7. Hand-held machine tool according to one of the preceding claims, characterized in that the insulating means (44d) has at least one recess (64) introduced in the axial direction (28).
8. Hand-held machine tool according to one of the preceding claims, characterized in that the insulating means (70b) bears in an open manner in the form of a ring on the motor housing (68) and on the housing cover (72) and has a gap (100) - in particular in the radial direction (76).
9. Hand-held machine tool according to one of the preceding claims, characterized in that the insulating means (44a, 44b, 70a, 70b) is fitted to the motor housing (22a, 22b, 68) or the housing cover (26a, 26b, 72) so as to be preloaded in the radial direction (30, 76).
10. Hand-held machine tool according to one of the preceding claims, characterized in that the insulating means (44b) engages in the shape of an L around the housing cover (26b) or the motor housing (22b).
11. Hand-held machine tool according to one of the preceding claims, characterized by a stop (58), which prevents complete compression of the insulating means (44d).
12. Hand-held machine tool mounting method for fitting an insulating means to a motor housing and a housing cover, characterized in that in a first step, the insulating means is pushed onto a step (46a) of the motor housing (22a) until the insulating means bears in the form of a ring on the guide means, and in a second step the housing cover is pushed onto the insulating means in the axial direction until the insulating means bears on a guide means.

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