EP3221230B1 - Handheld tool gear closure and handheld machine tool - Google Patents

Description

The present invention relates to a hand tool transmission closure with a base body for closing a transmission housing opening of a transmission housing of a hand tool machine, in particular a hammer drill or combi hammer.

An example is from the EP2433755A1 known. The present invention also relates to a hand tool with a hand tool gear lock.

Within the gear housing of a typical hand tool, a percussion with a piston, connecting rod and an anvil can be arranged. These are lubricated by a lubricant in the transmission housing, for example a transmission oil, in order to cooperate with as little friction as possible. Typically, the lubricant is introduced into the transmission housing via the transmission housing opening. In order to avoid that the lubricant exits the gear housing, the gear housing opening is closed by a base body of a hand tool gearbox closure. The main body may be formed as a plug.

It is an object of the present invention to provide an improved hand tool transmission closure, which favors an increased life of a hand tool. It is also an object of the present invention to provide a hand tool with such an improved hand tool gear lock.

With regard to the hand tool gearbox closure, the object is achieved in that the hand tool gearbox closure has a tube protruding from the base body, which runs in the gearbox housing when the base body closes the gearbox housing opening. The hand tool gearbox closure has an air channel which runs in a first air duct section through the base body and in a second air duct section through the tube, so that an air mass can flow through the air duct into and out of the gearbox housing.

Advantageously, an air mass, which is expanded due to the machine tool operation and especially by heating the lubricant located in the transmission housing, now escape from the transmission housing. As a result of the tube projecting from the main body according to the invention, an undesired escape of the lubricant from the transmission housing is avoided.

The invention includes the recognition that a lubricant, in particular oil, must not escape from a transmission housing, since otherwise the lubricating capacity drops, on the one hand, and, on the other hand, contaminates the surface of the machine tool that is visible to the user. The invention also includes the recognition that increases by the closed design of a gear housing and its closure by means of a body without air duct, the internal pressure of a transmission housing during operation of the machine tool to an undesirably high pressure level. A high pressure level is detrimental to the life and in particular the work performance data, for example, the delivered impact energy of the power tool. The hand tool closure according to the invention contributes to eliminating these disadvantages.

In a preferred embodiment, the tube has an inner diameter between 0.2 and 0.8 mm. The inside diameter can be between 0.4 and 0.6 mm. It has proved to be particularly advantageous if the inner diameter of the tube is 0.5 mm. By such a selected inner diameter advantageously occurring in the course of the tool operation in the transmission housing pressure pulsation is effectively damped.

In terms of improved temperature stability, it has proven to be advantageous if the tube is made of metal. Alternatively, the tube may be made of a temperature resistant plastic or the like.

In order to enable a further safety margin for a lubrication-free air exchange by the hand tool gear lock according to the invention, it has proven to be advantageous if the tube protrudes from the body in such a way that it ends in the vicinity of a percussion mechanism arranged in the gear housing when the body closes the gear housing opening. Preferably, the tube ends near a connecting rod of the striking mechanism. The tube may protrude from the body so that it reaches up to the axis of movement of the connecting rod, without interfering with the range of movement of the connecting rod, i. especially without coming into contact with the connecting rod.

It has proven to be advantageous if the tube is dimensioned in such a way, in particular with regard to length, inner diameter and / or Abragwinkel of the body that a capillary increase of lubricant is avoided within the tube. Is, for example, within the gearbox a typical gear oil having a viscosity of 5-20 mm 2 / s at 100 ° C, a density between 850 kg / m ³ to 900 kg / m ³ at 20 ° C and a surface tension of 20 - 30 N / m at 100 ° C, so is the preferred Inner diameter of the tube of 0.5 mm already sufficiently large to prevent adverse capillary increase of the gear oil in the tube.

In a particularly preferred embodiment, the hand tool gear lock has a pressure valve arranged in the first air duct section. About the pressure valve occurring in the transmission housing pressure can be degraded. Preferably, a negative pressure occurring in the transmission housing can be compensated via the pressure valve.

The pressure valve may be formed as a plate-shaped membrane with a central opening, which is preferably arranged on a pin, in particular on a centrally arranged pin of the base body. Thus, on the one hand results in a particularly robust, on the other hand, an easily mounted pressure valve. The plate-shaped membrane may be made of an elastomeric material, a rubber, or other elastically deformable material, or at least have such.

The pressure valve may be designed so that it opens only when exceeding a predetermined pressure difference, for example 2 bar, between ambient pressure and transmission pressure. This is advantageous, for example, if the machine tool has an electropneumatic hammer mechanism for which a desired overpressure is desirable.

Also preferably, the base body has an annular pressure distribution chamber which is closed by the pressure valve designed as a plate-shaped diaphragm, in particular when the transmission internal pressure and the ambient pressure (air pressure outside the transmission housing) are substantially equal.

In a preferred embodiment, the base body has a sealing ring, which is arranged to seal the base body circumferentially to the transmission housing opening.

Preferably, the base body is designed as a plug. A plug function of the main body can be effected, for example, by a sealing ring provided on the main body. Alternatively or additionally, the main body can have lamellae, which are designed to hold the main body in a gear housing opening frictionally.

With regard to the hand tool machine, the object is achieved in that the hand tool machine has a prescribed hand tool gear lock.

Further advantages will become apparent from the following description of the figures. In the figures, various embodiments of the present invention are shown. The figures, 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 a meaningful further combination.

In the figures, identical and similar components are numbered with the same reference numerals.

Fig. 1

eine schematische und perspektivische Darstellung eines Schnitts durch einen erfindungsgemäßen Handwerkzeuggetriebeverschlusses;

Fig. 2

eine schematische Darstellung des Handwerkzeuggetriebeverschlusses aus Fig. 1, der eine Getriebegehäuseöffnung verschließt;

Fig. 3

eine schematische Darstellung des Handwerkzeuggetriebeverschlusses aus Fig. 2 in rückseitiger Darstellung und eingezeichneter Schnittlinie A-A;

Fig. 4

eine schematische Schnittdarstellung des Handwerkzeuggetriebeverschlusses entsprechend der Schnittline A-A aus Fig. 3, wenn Getriebeinnendruck und Umgebungsdruck im Wesentlichen gleich sind;

Fig. 5

eine zweite schematische Schnittdarstellung des Handwerkzeuggetriebeverschlusses entsprechend der Schnittline A-A auf Fig. 3, wenn der Getriebeinnendruck den Umgebungsdruck übersteigt;

Fig. 6

eine dritte schematische Schnittdarstellung des Handwerkzeuggetriebeverschlusses entsprechend der Schnittline A-A auf Fig. 3, wenn der Getriebeinnendruck den Umgebungsdruck unterschreitet;

Fig. 7

eine schematische Darstellung einer Handwerkzeugmaschine mit einem erfindungsgemäßen Handwerkzeuggetriebeverschluss.

Show it:

Fig. 1

a schematic and perspective view of a section through a hand tool gear lock according to the invention;

Fig. 2

a schematic representation of the hand tool gearbox closure Fig. 1 closing a transmission housing opening;

Fig. 3

a schematic representation of the hand tool gearbox closure Fig. 2 in reverse and drawn section line AA;

Fig. 4

a schematic sectional view of the hand tool gear lock according to the section line AA Fig. 3 when transmission internal pressure and ambient pressure are substantially equal;

Fig. 5

a second schematic sectional view of the hand tool gear lock according to the section line AA Fig. 3 when the transmission internal pressure exceeds the ambient pressure;

Fig. 6

a third schematic sectional view of the hand tool gear lock according to the section line AA Fig. 3 when the transmission internal pressure falls below the ambient pressure;

Fig. 7

a schematic representation of a power tool with a hand tool gear lock according to the invention.

embodiments

A hand tool gear lock 10 in Fig. 1 has a base body 1, which is provided for closing a transmission housing opening, not shown. The hand tool gear lock 10 has a protruding from the base body 1 tube 2, which is provided in the present case as a metal tube. The hand tool transmission closure 10 has an air channel, which is formed by a first air duct section L1, which runs through the base body 1, and by a second air duct section L2, which extends through the tube 2. Through this air channel formed by the air duct sections L1, L2, an air mass LM can flow into and out of the transmission housing, not shown.

In the present case, the tube 2 has an inner diameter D of 0.5 mm. Since the tube 2 protrudes from the underside of the main body 1, the tube 2 extends within a transmission housing when the main body 1 closes a transmission housing opening. On the circumference of the base body 1, a sealing ring 6 is arranged, which in the present case consists of an elastically deformable rubber.

As in Fig. 1 1, the hand tool transmission closure 10 has a pressure valve 3 which is arranged in the first air duct section L1 and which in the present case is designed as a plate-shaped membrane with a central opening 3 '. The designed as a plate-shaped diaphragm pressure valve 3 is arranged on a central pin 4 of the base body 1. Furthermore, the main body 1 has an annular pressure distribution chamber 5, which is closed by the pressure valve 3 designed as a plate-shaped membrane.

Through the pressure valve 3, an air mass LM can escape from the transmission housing, which is illustrated by the dashed line pointing away from the main body 1 with arrow. Furthermore, an air mass LM can pass from the transmission environment into the transmission housing, not shown, via the pressure valve 3, which is indicated by the dashed line pointing in the direction of the tube 2 with an arrow. The pressure regulating function of the pressure valve 3 will be described with reference to FIGS 4 to 6 explained in more detail below.

Fig. 2 shows the hand tool gear 10, which closes a gear housing opening 70 of a gear housing 80. The base body 1 of the hand tool transmission closure 10 is held by a circumferentially extending sealing ring 6 in the gear housing opening 70 and held by a arranged below a swing plate 50 leaf spring 40 in its position.

Like also out Fig. 2 it can be seen, the tube 2 protrudes from the base body 1 in such a way that the tube 2 ends in the vicinity of a connecting rod 30 of the striking mechanism 60. More specifically, stands out the tube 2 in such a way from the base body 1 that it reaches up to the axis of movement A of the connecting rod 30, without interfering with the range of movement of the connecting rod 30, that is, in particular without coming into contact with the connecting rod 30 - regardless of a respective Pleuellage. By the in Fig. 2 shown installation situation, an air exchange of the gear housing 80 is achieved without a lubricant can escape from selbigem.

Fig. 3 shows the hand tool gear 10 with the base body 2 and the bottom projecting tube 2, wherein in Fig. 3 a rear view of the hand tool transmission closure 10 is shown (viewing direction from the right with respect to Fig. 2 Marked in Fig. 3 is a section AA, whose section AA below with reference to Fig. 4 is explained in more detail.

The in Fig. 4 Section AA shows the hand tool transmission closure 10 in its state when transmission internal pressure DI within the transmission housing 80 and ambient pressure DU outside the transmission housing 80 are substantially equal. Trained as a plate-shaped diaphragm pressure valve 3 rests on the pin 4 of the body 1 in undeflected state. There is no exchange of air via the first and second air duct section L1, L2 and the pressure valve 3 instead. This is the case, for example, if the hand tool was not in operation for a long time or during operation of the power tool when pressure equalization has already taken place.

Fig. 5 shows the state of the hand tool transmission closure 10 when the transmission internal pressure DI exceeds the ambient pressure DU, ie there is an overpressure in the transmission housing. This is the case, for example, when the percussion mechanism has heated a lubricant in the transmission housing. An air mass LM flows according to the dashed arrow into the protruding from the base body 1 tube 2 and moves along the air duct section L2 defined by the tube 2 in the direction of the body 1. From there, the air mass LM passes according to the dashed arrow direction in the pressure distribution 5, wherein the pressure distribution chamber 5 is arranged in the first air passage portion L1 of the base body 1. By means of an elastic deflection of the pressure valve 3 provided as a plate-shaped membrane, the air mass LM on the upper side of the main body 1 can escape therefrom. Like also out Fig. 5 it can be seen, the pressure valve 3 designed as a plate-shaped diaphragm is lifted off by a first valve seat 1 'situated on the outer circumference of the main body 1. After pressure equalization, the pressure valve 3 returns to its in Fig. 4 shown starting position back.

Fig. 6 now shows the state of the hand tool transmission closure 10 when the transmission internal pressure DI falls below the ambient pressure DU, ie, there is a negative pressure in the transmission housing 80. This is for example the case when the percussion cools down after a tool operation. An air mass LM indicated by the dashed arrow can flow into the annular pressure distribution chamber 5 on the upper side of the main body 1 via the pressure valve 3 designed as a plate-shaped membrane. In the process, the pressure valve 3 designed as a plate-shaped diaphragm is lifted off a second valve seat 1 "located on the central pin 4 of the main body 1. As indicated by the dashed line with arrow in the following, the air mass LM flows along the first air duct section L1 continues through the main body 1 until it reaches the air duct section L2 of the tube 2 protruding from the main body 1, to emerge from the tube 2 at the end thereof, as illustrated by the dashed arrow 2. After pressure equalization has taken place, the pressure valve 3 returns to its in Fig. 4 shown starting position back.

A hand tool 100 according to the invention is shown in FIG Fig. 7 shown. This has a tool housing 90 which encloses a transmission housing 80. Within the gear housing 80 a percussion 60 is arranged with a connecting rod 30. The hand tool gear lock 10 is arranged in a gear housing opening 70 and is covered on the upper side by a swing plate 50 of the power tool 100. The tube 2 protruding from the base body 1 of the hand tool transmission closure 10 terminates in the vicinity of the connecting rod 30 of the percussion mechanism 60. Tubes 2 protruding from the base body 1 prevent undesired escape of the lubricant from the transmission housing 80.

LIST OF REFERENCE NUMBERS

D

Inner diameter of the tube

DI

Gearbox internal pressure

YOU

ambient pressure

L1

first air duct section

L2

second air duct section

LM

air mass

1

body

1'

first valve seat

1"

second valve seat

2

tube

3

pressure valve

3 '

central opening

4

central pin

5

pressure distribution

6

seal

10

Hand Tools Transmission closure

30

pleuel

40

leaf spring

50

vibration plate

60

striking mechanism

70

Gearbox housing opening

80

gearbox

90

tool housing

100

Hand tool

Claims (10)

1. Hand tool gear closure (10) with a base body (1) for closing a gear housing opening (70) of a gear housing (80) of a hand machine tool (100), particularly a hammer drill or a combination hammer,
   characterised in that the hand tool gear closure (10) has a tube (2) projecting from the base body (1), which runs in the gear housing (80), if the base body (1) closes the gear housing opening (70), in which the hand tool gear closure (10) has an air channel (L1, L2), which runs in a first air channel section (L1) through the base body (1) and in a second air channel section (L2) through the tube (2), so that an air mass (LM) may flow through the air channel (L1, L2) into and out of the gear housing (80).
2. Hand tool gear closure (10) according to claim 1,
   characterised in that the tube (2) has an internal diameter (D) of between 0.2 and 0.8 mm, preferably 0.5 mm.
3. Hand tool gear closure (10) according to claim 1 or 2,
   characterised in that the tube (2) projects from the base body (1) in such a way that it ends near a striking mechanism (60), particularly a connecting rod (30) of the striking mechanism (60), arranged in the gear housing (80), if the base body (1) closes the gear housing opening (70).
4. Hand tool gear closure (10) according to one of the previous claims,
   characterised in that the hand tool gear closure (10) has a pressure valve (3) arranged in the first air channel section (L1), through which an excess pressure occurring in the gear housing (80) may be reduced.
5. Hand tool gear closure (10) according to claim 4,
   characterised in that a vacuum occurring in the gear housing (80) may be compensated through the pressure valve (3).
6. Hand tool gear closure (10) according to claim 4 or 5,
   characterised in that the pressure valve (3) is made as a plate-shaped membrane with a central opening (3'), which is arranged on a pin (4) of the base body (1).
7. Hand tool gear closure (10) according to claim 6,
   characterised in that the base body (1) has a ring-shaped pressure distribution chamber (5), which is closed by the pressure valve (3) made as a plate-shaped membrane, if the pressure inside the gear (DI) and the ambient pressure (DU) are essentially the same.
8. Hand tool gear closure (10) according to one of the previous claims,
   characterised in that the base body (1) has a sealing ring (6), which is arranged to seal the base body (1) to the gear housing opening (70) on the circumference.
9. Hand tool gear closure (10) according to one of the previous claims,
   characterised in that the base body (1) is made as a plug.
10. Hand machine tool (100), particularly a hammer drill or a combination hammer, with a gear housing (80) enclosed by a tool housing (90), which may be accessed through a gear housing opening (70),
    characterised in that the hand machine tool (100) has a hand tool gear closure (10) according to one of the previous claims.

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