WO2012143176A1

WO2012143176A1 - Striker bolt

Info

Publication number: WO2012143176A1
Application number: PCT/EP2012/054203
Authority: WO
Inventors: Otto Baumann; Hardy Schmid
Original assignee: Robert Bosch Gmbh
Priority date: 2011-04-19
Filing date: 2012-03-12
Publication date: 2012-10-26
Also published as: EP2699391A1; DE102011007699A1; CN103476550A

Abstract

The invention relates to a striker bolt for a striker device (10), in particular of an impact, drill and/or chipping hammer (12), having a main body (14). According to the invention, the main body (14) comprises at least two different hard areas.

Description

Description of the firing pin

State of the art

There are already firing pin for percussion devices, in particular a hammer, drill and / or chisel, with a body known.

Disclosure of the invention

The invention relates to a firing pin for a percussion device, in particular a hammer, drill and / or chisel hammer, with a base body.

It is proposed that the base body has at least two different hard areas. A "firing pin" is to be understood as meaning, in particular, a component of a percussion device which is movably mounted and / or is provided for impulse transmission from a racket to a tool Part of the firing pin to be understood with a main extension in the direction of a direction of impact. The firing pin preferably has an integrally formed on the base body supporting region, which advantageously in the radial

Direction over at least a portion of the body protrudes and is intended to support the firing pin in an impact position of the firing pin in the axial direction. In this context, a "hardness" of a range is to be understood as meaning a mechanical resistance that a material opposes to the mechanical penetration of a harder specimen matched to different tasks matched the material properties of the firing pin.

Advantageously, the base body has at least one hard tool contact region and at least one viscous residual region. A "tool contact area" is to be understood as meaning in particular a region of the base body which is provided for impulse transmission of a pulse of the firing pin, in particular on a tool inserted into a tool holder of the hammer, drill and / or chisel hammer. Area should be understood in this context, in particular an area with a high degree of hardness. In particular, the hardness of at least the surface of the tool contact area should advantageously be increased relative to a hardness of at least one residual area of the main body. A hard area can be achieved by a particularly high surface hardness. Preferably, a hard area is achieved by a particularly thick cured material layer. In particular, the thickness of a cured material layer is compared to the thickness of a hardened

Material layer of at least one remaining region of the body advantageously be increased. The tool contact region preferably has a hardness of 680-760 HV10 (Vickers). In this context, a "tough" region is to be understood as meaning, in particular, a region which has great resistance to crack propagation and / or fracture By "tempering", in this context, heating is to be understood up to a temperature in which the toughness of a material increases

Microstructure change takes place. Preferably, at least one residual area during curing and / or coating of the tool contact area can be covered with a covering means, in particular by copper. An undesired hardening and / or coating of the remaining area can be avoided by the covering means. The hard tool contact area can provide beneficial momentum transfer from the firing pin to the tool or other body. to which the firing pin is to transmit a pulse. By compared to the remaining region of the body reduced elasticity of the hard tool contact area energy and / or momentum losses can be reduced. The tough residual area can be particularly resistant to the formation of cracks and / or material fractures. A lifetime of

Striker can be increased advantageously.

It is proposed that the tool contact area has a deeply hardened surface. In this context, a "deep-hardened surface" should be understood as meaning, in particular, that a hardened material layer has a depth perpendicular to the surface of at least 1 millimeter A variety of suitable hardening methods are known to the person skilled in the art: In particular, the tool contact region can be case hardened A particularly thick, hard layer can be achieved. A hardening temperature can be generated in a particularly targeted manner in the tool contact area of the base body, a particularly wear-resistant surface can be produced, and a particularly effective impulse transmission of the firing pin can be achieved.

It is further proposed that the tool contact area is covered by a hard layer. In this context, a "hard layer" is to be understood as meaning, in particular, a hard material layer which is applied permanently to the tool contact region and / or which is produced in the tool contact region by introducing a further element For example, hard coating may be formed by incorporating carbon, boron and / or nitrogen into a base material of the firing pin Preferably, at least the tool contact region is case hardened, borated and / or nitrided to produce the hard layer The tool contact region may preferably have a deeply hardened surface that is covered by another hard layer, which may be particularly hard and wear-resistant Tool contact area can be achieved with a particularly advantageous momentum transfer.

It is further proposed that the remaining area has a tough core area with a surface hardening. In this context, "surface hardening" is to be understood as meaning, in particular, a thin, hard layer., In particular, the hard layer may be thinner than the deep-hardened surface of the tool contact region Surface hardening, like the deep-roughened surface, can be achieved by a hardening process, with surface hardening preferably taking place perpendicularly to the surface of the firing pin, with surface hardening preferably being achieved by mechanical hardening, such as Rolling and / or rolling can be produced Advantageously, wear of the firing pin can be reduced.The tough core region can effectively prevent breakage of the firing pin and / or cracking nn a surface quality can be further improved. A breaking strength can be further improved. Wear on surface sealing rings can be reduced.

In a particularly advantageous embodiment of the invention, the firing pin is integrally formed. By "in one piece" should be understood in particular to be at least materially bonded, for example by a welding process, a bonding process, an injection molding process and / or another process that appears expedient to a person skilled in the art, and / or advantageously shaped in one piece, for example by a production from a casting and / or by a production in a single or multiple component spraying process and advantageously from a single blank .Preferably the firing pin can be produced from a blank from a single, in particular curable base material Fastening points can be avoided and the firing pin can be particularly durable.

Advantageously, a hand-held power tool, in particular a hammer, drill and / or chisel, with a percussion mechanism, a erfindungsge- according to the firing pin. It can be achieved a particularly effective, wear-resistant and durable hand tool.

Furthermore, a method for producing a striker according to the invention is proposed. The striker may be made in one or more process steps from a tough, hardenable material, such as a steel, in particular from a tempering steel. Preferably, at least the remaining area can be surface-hardened. Particularly preferably, the tool contact region can be deeply hardened in a further method step. In particular, the tool contact region can be hardened by case hardening. Particularly preferably, the tool contact region can be heated inductively to a hardening temperature. Preferably, the residual area can be softened softer than the tool contact area. In this context, a "softer" quenching is to be understood as meaning that a temperature reduction takes place more slowly after a hardening temperature has been reached.A further method known to those skilled in the art for producing a deep-hardened surface is conceivable be manufactured particularly inexpensive and reliable.

Advantageously, the residual area is protected by a covering means during a surface treatment of the tool contact area. In this context, a "surface treatment" should be understood to mean hardening and / or coating of the surface of the tool contact area, in particular, the remaining area can be covered with copper, the remaining area can be effectively excluded from the surface treatment A masking agent can also prevent coating of the residual area with a hard layer of the tool contact area

Remaining area can be ensured.

It is further proposed that a hardness of the remaining portion is reduced by a tempering method. In particular, the remaining region can be annealed inductively. Particularly preferably, the residual region can be tempered at a higher temperature than the tool contact region. The toughness of the residual area can be further improved. Cracking and / or breakage of the firing pin in the remaining area can be prevented particularly effectively.

drawing

Further advantages emerge from the following description of the drawing. In the drawings, embodiments of the invention are 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.

Show it:

1 is a schematic representation of a hammer drill with a percussion device,

2 is a sectional view of a section of the hammer mechanism of a hammer drill,

3 shows a sectional drawing of a firing pin according to the invention, FIG. 4 shows process steps of a method for producing a firing pin according to the invention, FIG.

5 shows method steps of a further method for producing a firing pin according to the invention and

Fig. 6 is a sectional view of a firing pin according to the invention in a second embodiment.

Description of the embodiments

Figure 1 shows a schematic representation of a trained as a hammer drill 12a hand tool with a percussion device 10a with a firing pin 36a according to the invention. The percussion device 10a is provided for generating a striking drive of a tool 30a in a direction of impact 50a. The percussion device 10a contains the Schlagbol- zen 36a (Figure 2) with a main body 14a, wherein the base body 14a has two different hard areas. The main body 14a of the firing pin 36a has a hard tool contact area 16a and a tough residual area 18a (FIG. 3). The tool contact region 16a is arranged at an end 38a of the main body 14a of the firing pin 36a, which

Impact pulses on the tool 30a transmits. The tool contact region 16a has a deep-hardened surface 20a. Preferably, the tool contact region 16a is case hardened. A depth of the hard layer 22a is at least as great as a radius 32a of the base body 14a in the tool contact region 16a about the direction of impact 50a, so that the base body 14a in FIG

Tool contact area 16a is completely through hardened. The remaining area 18a has a tough core area 24a with a surface hardening 26a. The firing pin 36a is integral with the base 14a and a support portion 34a. With the support portion 34a, the firing pin 36a is supported in an impact position of the firing pin 36a in the axial direction on the

Impact device 10a from. The support region 34a has a hardness and a surface corresponding to the remaining region 18a.

In a method (FIG. 4) for producing a firing pin 36a, a residual area 18a is protected by a covering means 28a, for example a copper paste, during a surface treatment of a tool contact area 16a. On the firing pin 36a, the covering means 28a is applied in a first method step 40a. In a further method step 42a, the firing pin 36a is case hardened. Due to the covering means 28a, no carbon can penetrate into the remaining region 18a during case hardening. Alternatively, in this method step 42a, another hardening process that appears appropriate to the person skilled in the art can also be used. In a further method step 44a, the covering means 28a is removed from the firing pin 36a. The remaining area 18a may additionally receive a surface hardening 26a. The surface hardening 26a is produced prior to the surface treatment of the

Tool contact portion 16a at least the remaining portion 18a of the firing pin 36a is rolled.

In a further method (FIG. 5) for producing the firing pin 36a, the hardness of the remaining portion 18a is reduced by a tempering method. In one In a first method step 46a, the firing pin 36a is hardened. The deep-hardened surface 20a is formed. In a further method step 48a, the residual region 18a is inductively heated up to a tempering temperature, so that its hardness is reduced again. For this purpose, an induction coil 52 is moved over the remaining area 18a, so that it heats up. The tool contact area 16a is excluded from inductive heating, so that its temperature remains below the tempering temperature. The tool contact region 16a does not change its microstructure and the deep-hardened surface 20a is retained. The remaining area 18a may additionally receive a surface hardening 26a. The entire firing pin 36a or parts of the firing pin 36a can be coated with a wear-resistant layer, for example, the firing pin 36a can be completely or partially bored and / or nitrided.

Combinations of the proposed methods for producing the firing pin 36a, which seem useful to the person skilled in the art, are possible. During one

When the tool contact portion 16a is hardened, the residual portion 18a can be protected by the cover member 28a. After hardening, by additional tempering of the residual region 18a, its toughness can be further increased. The following description and the drawing of a further embodiment is essentially limited to the differences between the exemplary embodiments, reference being made in principle to the drawings and / or the description of the other exemplary embodiment with respect to identically named components, in particular with regard to components having the same reference numbers can. To distinguish the embodiments, instead of the letter a of the first embodiment of the letter b the reference numerals of the further embodiment are readjusted.

FIG. 6 shows a firing pin 36b with a main body 14b, wherein the main body 14b has two regions of different hardness. The main body

14b of the firing pin 36b has a hard tool contact area 16b and a tough residual area 18b. The tool contact region 16b has a deep-hardened surface 20b. The tool contact area 16b is additionally covered by a hard layer 22b. The hard layer 22b is created by boring the base body and permanently connected to the firing pin 36b.

Claims

Firing pin for a striking mechanism device (10), in particular a hammer, drill and/or chisel hammer (12), with a base body (14), characterized in that the base body (14) has at least two regions of different hardness.

Firing pin according to claim 1, characterized in that the base body (14) has at least one hard tool contact area (16) and at least one tough remaining area (18).

Firing pin according to claim 2, characterized in that the tool contact area (16) has a deeply hardened surface (20).

Firing pin at least according to claim 2, characterized in that the tool contact area (16) is covered by a hard layer (22).

Firing pin at least according to claim 2, characterized in that the remaining area (18) has a tough core area (24) with a surface hardening (26).

Firing pin according to one of the preceding claims, characterized by a one-piece design.

Hand tool, in particular impact, drill and/or chisel hammer (12), with a striking mechanism (10) with a firing pin (36) according to one of the preceding claims.

Method for producing a firing pin (36) according to one of claims 1 to 7.

9. A method for producing a firing pin (36) according to claim 8, characterized in that a remaining area (18) is protected by a covering means (28) during a surface treatment of a tool contact area (16).

10. A method for producing a firing pin (36) at least according to claim 8, characterized in that a hardness of a residual area (18) is reduced by a tempering process.