WO2001053045A1

WO2001053045A1 - Hand machine tool

Info

Publication number: WO2001053045A1
Application number: PCT/DE2001/000045
Authority: WO
Inventors: Helmut Wanek; Markus Heckmann
Original assignee: Robert Bosch Gmbh
Priority date: 2000-01-22
Filing date: 2001-01-09
Publication date: 2001-07-26
Also published as: EP1252000B1; DE50101843D1; CN1301828C; CN1395520A; EP1252000A1; JP2003522034A; DE10002749A1

Abstract

The invention relates to a hand machine tool for receiving tools with a grooving shank. Said tool holder comprises a base body (12) with at least one radially displaceable locking body (14) which can be introduced into a groove in the tool that is closed at the shank end and which is then held in its locking position by a blocking element (16). Said blocking element can be guided into a position in which the locking body (14) is radially released by means of an actuating element (18). At least one sealing device (20, 22, 24, 26, 28) is also provided, said sealing device outwardly sealing at least one chamber (30, 32) surrounding a locking body (14).

Description

Hand tool

State of the art

The invention is based on a hand tool according to the preamble of claim 1.

From DE 197 24 532.3, a rotary hammer with a tool holder that can be driven in a rotating and striking manner is known. The tool holder has a base body which is made in one piece with a spindle sleeve. The base body has a receiving bore into which a shank of a tool can be inserted and can be locked by means of a locking device. The locking device has a locking ball which is arranged in an opening in the base body and can be inserted into a groove of a tool which is closed at the shaft end.

In a locking position, the locking ball is covered radially on the outside by a locking sleeve. The locking sleeve is axially displaceably mounted on the base body. The

Locking sleeve can be axially inserted into an Guiding direction of the tool against the force of a preloaded coil spring in an unlocked position in which a space in the locking sleeve allows a radial escape of the locking ball from the groove of the tool shank to release the tool.

The spindle sleeve 'is mounted in a machine housing. The actuating sleeve surrounds a tool-side end of the machine housing with a sleeve-shaped extension. In order to guarantee the mobility of the actuating sleeve relative to the machine housing, there is an annular gap between the extension and the machine housing. The actuating sleeve delimits a space surrounding the locking ball radially outwards, which is delimited inwards by the base body. The space is protected against dust on the tool side by a dust protection cap, which is attached to the base body and seals radially inwards to the base body and radially outwards to the actuating sleeve. On the machine side, the room is protected against the ingress of drilling dust by a sealing device.

The sealing device has a support ring which serves for supporting the helical spring on the machine side and for this purpose has a cylindrical guide extension for the helical spring. The support ring is axially secured on the machine side to a shoulder of the spindle sleeve. In the support ring there are circumferential grooves on the inner circumference and on the outer circumference, in each of which a sealing ring is arranged. The outer sealing ring arranged in the radially outer circumferential groove seals the space between the actuating sleeve and the support ring and the inner sealing ring arranged in the radially inner circumferential groove. tring seals the space between the support ring and the base body.

Advantages of the invention

The invention relates to a handheld power tool, in particular a drilling and / or chiseling tool, with a tool holder which can be driven in a striking and / or rotating manner, for holding tools with a groove shank, one

Has base body with at least one radially displaceable locking body which can be inserted into a groove of the tool which is closed at the shank end and is held in its locking position by a locking element which can be guided into a position which releases the locking body radially, and with at least one sealing device , which seals at least one space surrounding a locking body to the outside.

It is proposed that the sealing device have at least one sleeve-shaped component separate from the actuating element, which at least partially delimits the space in the radial direction. The space can advantageously be formed independently of the actuating element and the sealing device can seal the space by means of sealing surface pairs that are at least mutually at least during operation, even when the actuating element is stationary and the rotating base body, for example when the actuating element contacts the wall during operation. A particularly advantageous sealing effect can be achieved, the ingress of dust can at least largely be avoided and, as a result, less wear on the Tool and in particular on the base of the tool holder and a long service life can be achieved. In addition, little wear can be achieved on the sealing device.

In order to at least largely avoid friction between the actuating element and the sleeve-shaped component when the actuating element is at a standstill, the actuating element advantageously has at least a radial distance from the sleeve-shaped component.

In a further embodiment of the invention, it is proposed that the sealing device have at least one sleeve-shaped, elastically deformable component. In spite of an adjustment movement of the locking element, pairs of sealing surfaces resting against one another can always be achieved. The pairs of sealing surfaces can be held against one another with large contact forces without hindering movement or causing large coefficients of friction, and overall a particularly advantageous sealing effect can be achieved.

If at least one pair of sealing surfaces is held on top of one another by a compression spring holding the locking element in its locking position, large contact forces supporting the sealing effect can advantageously be achieved between the sealing surfaces without additional components. Furthermore, the sleeve-shaped, in particular the elastically deformable, component advantageously encloses the compression spring and seals on its end faces to adjacent components, as a result of which the compression spring and the sleeve-shaped component can advantageously be designed as a preassembled assembly. Furthermore, the compression spring could also be made of sleeve-shaped, in particular elastically deformable partially overmolded. By means of a compression spring surrounded by the sleeve-shaped component, a simple dust seal can be achieved, which can easily be used in numerous design variants. The sleeve-shaped component can be arranged radially inside the compression spring or radially outside the compression spring.

It is also proposed that a pair of sealing surfaces be arranged axially in front and a pair of sealing surfaces axially after the locking body, and in both pairs of sealing surfaces a sealing surface is formed by the base body or by a component fastened to the base body. The sealing effect of the sealing device can be improved and, in particular, a space surrounding the locking body can be created, into which a lubricant can advantageously be introduced and which, in addition to initial lubrication, can be used for permanent forced lubrication. It is advantageously possible to use an already existing recess for the locking body to supply lubricant into the room and to discharge it from the room into a receiving area of the tool holder and to lubricate the receiving area and the tool shank and to reduce wear. Additional recesses and components for forced lubrication can be saved.

A good sealing effect can be achieved in a structurally simple manner by the sleeve-shaped component engaging in at least one groove in the base body. Furthermore, an additional inexpensive seal can be achieved with a labyrinth seal between the actuating element and an adjacent component, for example a protective cap attached to the base body. With the labyrinth seal a penetration can from .dust and dirt to the sleeve-shaped component and the escape of lubricant from the room to the outside.

drawing

Further advantages result from the following description of the drawing. Exemplary embodiments of the invention are shown in the drawing. 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 useful further combinations.

Show it:

1 shows a longitudinal section through a tool holder of a rotary hammer, FIG. 2 shows a variant according to FIG. 1 with two spring-loaded sealing surface pairs, FIG. 3 shows a variant according to FIG. 2 with a preassembled module, consisting of an elastically deformable sealing sleeve and a compression spring,

4 shows a variant according to FIG. 1 with a space sealed in the axial direction before and after a locking body to form a base body of the tool holder, FIG. 5 shows a variant according to FIG. 4 with a sheet metal sleeve, Fig. 6 shows an elastically deformable sealing sleeve from Fig. 5 in the assembled state in a locking position of a tool holder and

Fig. 7, the sealing sleeve of Fig. 6 in the assembled state in an unlocked position of a tool holder.

Description of the embodiments

1 shows a section of a rotary hammer with a tool holder 10, which is arranged in a lower housing shell 84 and can be driven in a rotating and impacting manner, for receiving tools with a groove shank. The tool holder 10 has a base body 12 with a radially displaceable locking ball 14 which can be inserted into a closed groove of the tool at the end of the shaft and is held in its locking position by a locking sleeve 16 which is axially movable within limits and a holding sleeve 56.

The locking sleeve 16 is loaded via the holding sleeve 56 with a compression spring 46 in the direction of its locking position. The compression spring 46 is supported on the machine side on a support ring 54. The locking sleeve 16 is supported on the side facing away from the compression spring 46 by a ring 76 and a snap ring 78 on the base body 12. In the locking position of the locking ball 14, the locking sleeve 16 radially covers the locking ball 14 and the holding sleeve 56 secures the locking ball 14 in the axial direction. When the tool is inserted, the locking ball 14 is displaced by the shaft end of the tool in a recess 74 in the direction of insertion of the tool. The retaining sleeve 56 is displaced via the locking ball 14 against the compression spring 46, which creates a free space between the locking sleeve 16 and the retaining sleeve 56, into which the locking ball 14 can move radially outward. The tool can be fully inserted. Then the prestressed compression spring 46 moves the retaining sleeve 56 into its starting position and the locking ball 14 m presses the groove of the

Tool. For rotary driving, 12 rotary driving webs 82 are arranged in a receiving bore 80 of the base body, which engage m open grooves at the end of the tool shank.

To remove the tool, the locking sleeve 16 is displaced with an actuating sleeve 18 against the holding sleeve 56 and against the compression spring 46 loading the holding sleeve 56, so that the locking ball 14 dodges radially outward and the tool can be removed. The compression spring then prints the retaining sleeves 56, the locking sleeves 16, the locking ball 14 and the actuating sleeve 18 back into their initial positions.

The tool holder 10 has a sealing device 20, which seals a space 30 surrounding the locking ball 14 to the outside. According to the invention, the sealing device 20 has an elastically deformable rubber sleeve 34 which is separate from the actuating sleeve 18 and which radially delimits the space 30 and encloses the support ring 54, the compression spring 46, the holding sleeve 56 and the locking sleeve 16. The rubber sleeve 34 seals the space 30 on the support ring 54 and on the locking sleeve 16 to the outside from. A dust protection cap 86 is positively attached to the base body 12 at the tool-side end via a latching connection 88, which seals the area of the locking ball 14 against dust on the tool side via a gap seal 90 to the actuating sleeve 18. In the tool holder 10 there is also a striker 112, which seals the receiving bore 80 on the machine side via seals (not shown) arranged in grooves 114, 116.

If the locking between the tool and the tool holder 10 is released by the locking sleeve 16 being displaced via the actuating sleeve 18 against the compression spring 46 or the tool shank being locked, the rubber sleeve 34 can deform elastically without pairs of sealing surfaces 92, 94 between the support ring 54 and the rubber sleeve 34 and the rubber sleeve 34 and the locking sleeve 16 lifted apart from each other can still be moved to each other. In order to prevent the rubber sleeve 34 from lifting axially from the support ring 54 or from the locking sleeve 16, this is braced with the support ring 54 and the locking sleeve 16, i.e. non-positively connected.

Furthermore, the actuating sleeve 18 is at a radial and axial distance 110 from the rubber sleeve 34. When the actuating sleeve 18 comes into contact with the wall during operation and the actuating sleeve 18 comes to a standstill, the rubber sleeve 34 can continue to rotate together with the base body 12. Wear between the rubber sleeve 34 and the actuating sleeve 18 is avoided.

For initial lubrication of the receiving bore 80, the space 30 is provided with a not shown in the recess 74. filled with viscous and temperature-resistant lubricants. When the tool is inserted, the locking ball 14 is displaced radially outward, the volume of the space 30 is reduced and the lubricant is pressed out of the space 30 into the receiving bore 80.

FIG. 2 shows a variant of the exemplary embodiment in FIG. 1 with a sealing device 22. Components that remain essentially the same are basically numbered with the same reference numerals in the exemplary embodiments described. Furthermore, with regard to the same features and functions, reference can be made to the description of the exemplary embodiment in FIG. 1.

The sealing device 22 has an elastically deformable rubber sleeve 36 which surrounds the compression spring 46 and the holding sleeve 56 and which seals the space 30 to the support ring 54 and the locking sleeve 16 to the outside. Sealing surface pairs 48, 50 between the support ring 54 and the rubber sleeve 36 and between the rubber sleeve 36 and the locking sleeve 16 are held together by the compression spring 46.

A variant shown in FIG. 3 has a sealing device 24 with an elastically deformable rubber sleeve 38, which forms a preassembled module with the compression spring 46. The rubber sleeve 38 surrounds the compression spring 46 and seals the space 30 on the end faces of the support ring 54 and the holding sleeve 56 to the outside. Sealing surface pairs 48, 52 between the support ring 54 and the rubber sleeve 38 and between the rubber sleeve 38 and the holding sleeve 56 are held against one another by the compression spring 46. An exemplary embodiment shown in FIG. 4 has a sealing device 26 with an elastically deformable rubber sleeve 40. The rubber sleeve 40 encloses the support ring 54, the compression spring 46, the holding sleeve 56, the locking sleeve 16, the ring 76 and the snap ring 78 and seals a space 32 to the support ring 54 and to the base body 12. On the machine side, the rubber sleeve 40 encloses the support ring 54 radially and from two axial sides and engages in the groove 68 of the base body 12 on the tool side. A pair of sealing surfaces 58 is arranged axially in front and a pair of sealing surfaces 62 is arranged axially behind the locking ball 14. In order to achieve a good hold of the rubber sleeve and a high wear resistance, the rubber sleeve can be reinforced with a fabric in various areas, for example in the area of the support ring 54, the compression spring 46, the holding sleeve 56 and / or the locking sleeve 16.

With the actuating sleeve 18, the locking sleeve 16 can be moved against the compression spring 46 via the rubber sleeve 40 and the ring 76. The rubber sleeve 40 is elastically deformed, the sealing surfaces of the sealing surface pairs 58, 62 always resting on one another.

A tough and heat-resistant lubricant is introduced into the space 32 for permanent forced lubrication via the recess 74. When inserting a tool into the

Tool holder 10, the locking ball 14 is moved radially outwards. The volume of the space 32 is reduced and the lubricant is pressed through the recess 74 into the receiving bore 80. The area around the rubber sleeve 40 is also via an O-ring 96 arranged between the actuating sleeve 18 and the housing shells 84 and via a ne labyrinth seal 72 between the actuating sleeve 18 and an adjacent dust cap 70 sealed.

5 shows a variant of the exemplary embodiment in FIG. 4 with a sealing device 28 which, in addition to a rubber sleeve 42 arranged on the tool side, elastically deformable and folded in multiple layers, has a sheet metal sleeve 44 on the machine side. The sheet metal sleeve 44 seals the space 32 on the machine side to form an O-ring 66, which is fastened in a circumferential groove 100 of a support ring 98 for the compression spring 46. The space 32 is sealed between the support ring 98 and the base body 12 via an O-ring 102, via which the support ring 98 is supported on the machine side on a shoulder 104 of the base body 12. On the tool side, the support ring 98 is supported on the base body 12 via a clamping ring 106.

On the tool side, the rubber sleeve 42 seals the space 32 between the sheet metal sleeve 44 and the locking sleeve 16 and at a second end to the base body 12. At its second end, the rubber sleeve 42 engages in a groove 68 of the

Basic body 12. The sheet metal sleeve 44 forms a sealing surface pair 60 axially with the O-Rmg 66, and the rubber sleeve 42 forms a sealing surface pair 64 axially with the basic body 12 after the locking ball 14.

With the actuating sleeve 18, the locking sleeves 16 can be moved against the compression spring 46 via the sheet metal sleeves 44 and the rubber sleeves 42. The actuating sleeve 18 engages radially outside a region 108 of the gui-sleeve 42 which is folded in multiple layers, as a result of which the region 108 folded in several layers can unfold advantageously during the unlocking process. FIG. 6 shows the rubber sleeve 42 in the locked position and FIG. 7 shows the rubber sleeve 42 in an unlocked position of the tool holder 10. The sheet metal sleeve 44 slides on the O-ring 66. As in the exemplary embodiment from FIG , introduced a tough and heat-resistant lubricant for permanent forced lubrication through the recess 74.

reference numeral

10 Tool holder 56 component

12 basic body 58 pair of sealing surfaces

14 locking body 60 pair of sealing surfaces

16 blocking element 62 pair of sealing surfaces

18 actuator 64 pair of sealing surfaces

20 sealing device 66 component

22 sealing device 68 groove

24 sealing device 70 component

26 Sealing device 72 labyrinth seal

28 sealing device 74 recess

30 room 76 ring 32 room 78 snap ring

34 Component 80 location hole

36 Component 82 Swivel drive bars

38 Component 84 housing shell

40 component 86 dust protection cap 42 component 88 snap-in connection 44 component 90 gap seal

46 compression spring 92 pair of sealing surfaces

48 pair of sealing surfaces 94 pair of sealing surfaces

50 pair of sealing surfaces 96 O-ring

52 pair of sealing surfaces 98 support ring

54 component 100 groove 102 O-ring

104 paragraph

106 tension ring

108 area

110 distance

112 strikers

114 groove

116 groove

Claims

Expectations

1. Hand tool, in particular rotary and / or chisel hammer, with a striking and / or rotating tool holder (10) for receiving tools with a groove shaft, which has a base body (12) with at least one radially displaceable locking body (14) Can be inserted into a closed groove of the tool at the shaft end and is held in its locking position by a locking element (16), which can be guided via an actuating element (18) into a position that releases the locking body (14) radially, and with at least one sealing device (20, 22, 24, 26, 28) which seals at least one space (30, 32) surrounding a locking body (14) to the outside, characterized in that the sealing device (20, 22, 24, 26, 28) at least one of the actuating element ( 18) has a separate, sleeve-shaped component (34, 36, 38, 40, 42, 44) which at least partially delimits the space (30, 32) in the radial direction.

2. Hand tool according to claim 1, characterized in that the actuating element (18) has at least a radial distance (110) to the sleeve-shaped component (34, 36, 38, 40, 42, 44).

3. Hand tool according to claim 1 or 2, characterized in that the sealing device (20, 22, 24, 26, 28) has at least one sleeve-shaped, elastically deformable component (34, 36, 38, 40, 42).

4. Hand tool according to one of the preceding claims, characterized in that at least one pair of sealing surfaces (48, 50, 52) is held on top of one another by a compression spring (46) holding the locking element (16) in its locking position.

5. Hand tool according to claim 4, characterized in that the sleeve-shaped component (38) surrounds the compression spring (46) and seals on its end faces to adjacent components (54, 56).

6. Hand tool according to one of the preceding claims, characterized in that a pair of sealing surfaces (58, 60) axially in front and a pair of sealing surfaces (62, 64) axially after the locking body (14) and in both pairs of sealing surfaces (58, 60, 62, 64 ) a sealing surface is formed by the base body (12) or by a component (54, 66) attached to the base body (12).

7. Hand tool according to one of the preceding claims, characterized in that a lubricant is introduced into the space (30, 32).

8. Hand tool according to one of the preceding claims, characterized in that at least one sleeve-shaped component (40, 42) engages in at least one groove (68) of the base body (12).

9. Hand tool according to one of the preceding claims, characterized in that a labyrinth seal (72) is arranged between the actuating element (18) and an adjacent component (70).