GB2357724A

GB2357724A - Hammer drill

Info

Publication number: GB2357724A
Application number: GB0025776A
Authority: GB
Inventors: Gerhard Meixner; Jurgen Bauer
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1999-10-21
Filing date: 2000-10-20
Publication date: 2001-07-04
Also published as: CN1302710A; GB0025776D0; DE19950759A1

Abstract

A hammer drill has a drilling spindle (22) for driving a tool in a rotating manner, and a driving pinion (18) which is disposed perpendicularly to a longitudinal axis (29) of the said drilling spindle (22). The filter meshes with a driven toothing system (19) which is connected to the said drilling spindle (22) in a torsion-proof manner. The driven toothing system (19) is located in a plane perpendicular to the longitudinal axis (29) and parallel to an axis of rotation (32) of the driving pinion (18).

Description

2357724 Hammer drill

Prior art

The starting point of the invention is a hammer drill according to the precharacterising clause of claim 1. A hammer drill is already known (EPA-583 7 10) which has a drilling spindle for driving a tool in a rotating manner, the said drilling spindle being constructed as a hollow shaft with the striking mechanism accommodated in it. In that instance, the drilling spindle can be driven via a bevel pinion which meshes with a bevel wheel disposed on the said drilling spindle in a torsion-proof manner. Because of the tooth forces occurring in the bevel toothing system, the bevel wheel has to be mounted on the drilling spindle via a relatively broad guide region. The bevel gear unit therefore takes up a relatively large structural space and is relatively heavy. In addition, it requires manufacture which predominantly involves machining, a fact which increases the manufacturing costs.

Advantages of the invention In contrast to this, the hammer drill according to the invention having the features in claim 1 has the advantage of having a small, light and cost-effective toothedwheel gear unit for rotationally driving the drilling spindle.

Advantageous further developments of, and improvements to, the hammer drill according to the invention are possible as a result of the measures set out in the dependent claims.

2 An exemplified embodiment of the invention is represented in the drawings and explained in greater detail in the subsequent description. In the drawings: Figure 1 shows a longitudinal partial section through a hammer drill, and Figure 2 shows a diagrammatic representation of a driving pinion construe ed according to the invention and having a driven toothed wheel.

Description of the exemplified embodiment

In figure 1, 10 designates a hammer drill which has a driving motor 11 wit i a motor shaft 12 which carries a motor pinion 13 at the end. The motor pinion 13 is in engagement with a driving toothed wheel 14 which is mounted on an intermediate shaft 15 in a torsion-proof manner. The intermediate shaft IS is received in a rotatable manner in a part 16 of the housing. At its output end, the i: intermediate shaft 15 carries a driving pinion 18 which is in engagement wilh a driven toothing system 19 which is constructed on the end face of a toothed ng n' 20. Via a key-and-slot connection 21, the toothed ring 20 is connected, in a fo locking manner in the direction of rotation, to a drilling spindle 22 which, at nie end, drives a tool-holder, of which no further details are represented, for a to in a rotating manner. The drilling spindle 22 is constructed as a hollow shaft nd carries, in its interior, a striking mechanism of which no further details are represented. As regards the disclosure of the basic make-up of the hammer d -ill, reference is expressly made, at this point, to EP-A- 5 83 7 10.

The drilling spindle 22 is mounted in, inter alia, a guide sleeve 23 formed by the machine housing. The guide sleeve 23 forms an axial stop 24 for the toothed ing 20. The said toothed ring 20 may be axially secured by a guide sleeve 25 see figure 1, upper half of the section). Under these circumstances, the guide sI eve 3 is supported, at one end, on a projection 26 on the housing, which projection protrudes inwards in the form of a ring. As an alternative to this, the toothed ring 20 may also be axially secured directly on the drilling spindle 22 by means of a securing ring 27 (see figure 1, lower half of the picture).

The combination of toothing systems formed by the driving pinion 18 and the driven toothing system 19 is represented in plan view in figure 2, in the direction of viewing according to II-II in figure 1. The toothed ring 20 has, uniformly distributed in the peripheral direction, a multitude of individual teeth 28 which are disposed in a plane perpendicular to the longitudinal axis 29. Each tooth 28 has tooth flanks, 28a, b respectively, which are at a wedge-shaped angle to one another. The interstices 30 formed between adjoining teeth 28 are delimited by mutually opposed tooth flanks 28 b, a, which are located approximately parallel to one another. The driving pinion 18 is provided with a straight-toothed end-face toothing system 31 which is in engagement with the driven toothing system 19. A gear unit of this kind is also described as a "crown-wheel gear unit".

In the hammer drill 10, the toothed-wheel connection according to the invention has the advantage that the intermediate shaft 15 is particularly insensitive as regards position. Thus, the toothed-wheel connection according to the invention compensates for the differences in the axial length of the intermediate shaft 15. In addition, the toothed ring 20 can be manufactured largely without cutting, in a manner which is particularly favourable from the manufacturing point of view. Unfavourable tooth forces are reduced to a minimum on account of the straight toothing system used.

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Claims

Claims

Hammer drill having a drilling spindle (22) for driving a tool in a rotating manner, and having a driving pinion (18) which is disposed i perpendicularly to a longitudinal axis (29) of the said drilling spindle (22) and which meshes with a driven toothing system (19) which is connected to the 5 aid drilling spindle (22) in a torsion- roof manner, characterised in that the driven p toothing system (19) is located in a plane perpendicular to the longitudinal xis (29) and parallel to an axis of rotation (32) of the driving pinion (18).
2. Hammer drill according to claim 1, characterised in that the t eth t (28) widen outwards in the radial direction in a wedge-shaped manner, mutu lly opposed tooth flanks (28a, b) of adjoining teeth (28) being located approxima ely parallel to one another.
3. Hammer drill according to claim 1 or 2, characterised in that the driving pinion (18) carries a straight-toothed end-face toothing system (3 1).
4. Hammer drill according to claim 3, characterised in that the driving pinion (18) is constructed on the end of an intermediate shaft (15) in one piece.
5. Hammer drill according to claim 1, characterised in that the dr 1 toothing system (19) is constructed on a toothed ring (20) which is mounted axially displaceable manner on the drilling spindle (22) and is connected tc said drilling spindle (22) in a form-locking manner in the direction o,.rotati(
6. Hammer drill according to claim 5, characterised in that the toed ring (20) is axially secured between parts (23, 26) of a machine housing (16) belonging to the hammer drill by a guide sleeve (25) mounted on the drilling spindle (22).
7. Hammer drill according to claim 5, characterised in that the toothed ring (20) is axially secured by means of a securing ring (27) disposed on the drilling spindle (22).
8. Hammer drill substantially as herein described with respect to the accompanying drawings.