EP2318656A1

EP2318656A1 - Chisel holder having a weld as a wear protection element

Info

Publication number: EP2318656A1
Application number: EP09777093A
Authority: EP
Inventors: Thomas Lehnert; Christian Berning; Martin Lenz
Original assignee: Wirtgen GmbH
Current assignee: Wirtgen GmbH
Priority date: 2008-09-05
Filing date: 2009-07-10
Publication date: 2011-05-11
Anticipated expiration: 2029-07-10
Also published as: CN201581895U; TWI405898B; US20110204702A1; EP2318656B1; DE102008045825B3; CN101666229A; US8783785B2; CN101666229B; TW201014963A; AU2009289875A1; WO2010025788A1; AU2009289875C1; AU2009289875B2

Abstract

The invention relates to a chisel holder (20) for a cutting machine, road milling machine, surface miner, or the like, having a chisel receptacle (29), which comprises an insertion opening, and having a chisel supporting surface (26), wherein at least one wear protection element (40) is arranged in an area associated with the chisel supporting surface. In order to bring about effective wear protection in such a chisel holder at low cost, it is provided that the at least one wear protection element is designed as a weld (40) and is arranged at least in areas in at least one opening (41).

Description

CHISEL HOLDER WITH WELDING AS WEAR PROTECTIVE ELEMENT

The invention relates to chisel holder for a cutting machine, road milling machine, surface miner or the like with a chisel holder, which has an insertion and with a chisel support surface, wherein in one of the chisel support surface associated region at least one wear protection element is arranged.

Such a bit holder is known from US 6,585,327 B2. In this case, the chisel holder has a bore as a chisel holder. In this the chisel can be used interchangeably. In the area of the bore entry in each case a bore extension is provided, are soldered into the carbide rings. The chisel attachment is aligned with the holes passing through the carbide rings. The chisel inserted into the chisel holder is supported with its chisel head on a chisel support surface of the facing carbide ring. At the same time, both carbide rings also support the bit in the area of its tool shank and thus act as wear protection during operation. The use of hard metal material for the purpose described above significantly increases the production costs.

In addition to the high material price, a tailor-made dimensioning of the receptacles and the absolutely aligned fixation of the carbide rings with respect to the drill bit bore designed as a bore is required. The fixation is done by soldering. This requires a high energy input and thermal stresses are introduced into the chisel holder in the soldering oven. But even without these stresses large-area carbide parts tend to break very easily due to their extreme brittleness. Occasionally, therefore, several smaller dimensioned carbide inserts were installed on chisel holders in the prior art, as shown in US Pat. No. 5,251,964. As a result, the production cost, which is due to the precise arrangement and alignment of the hard metal elements to each other, further increased.

Furthermore, DE 39 29 609 A1 discloses a method in which the bit support surface of the bit holder affected by wear is protected by means of an armor consisting of wear-resistant material. In this case, a powder mixed with hard metal particles and solder particles is melted onto the surface to be protected. The disadvantage here is that a non-planar surface results, which is not exactly orthogonal to the central longitudinal axis of the bit holder. By such a surface protection but then the rotational behavior of the bit is adversely affected. It is an object of the invention to provide a bit holder of the type mentioned, which is protected effectively and with little parts and manufacturing costs from the wear of the bit.

This object is achieved in that the at least one wear protection element is formed as a weld and at least partially disposed in at least one recess.

The weld is formed by a welding filler, which by means of a usual. Welding process can be introduced with low production costs in the recess. The welding is characterized by a high resistance to abrasion and thus sets the chisel or the wear plate high wear resistance. The wear characteristics of the chisel holder can be adjusted to a large extent by the choice of the suitable welding filler material. Thus, for different road surfaces to be processed (concrete, asphalt) or raw materials (coal, sandstone, salt, etc.) wear-optimized bit holder can be provided.

The fact that the weld is received in a specially provided recess, surfaces that are required for a perfect tool function and a long service life, unaffected by the wear element.

According to a preferred variant of the invention it can be provided that the recess is formed as a groove. The groove can be introduced, for example, by mechanical machining in a simple manner in the bit holder. Depending on the desired wear characteristics almost any groove geometries can be manufactured. By choosing a suitable groove for the purpose of the wear can be controlled. For example, provision may be made for the bit support surface to encircle around the insertion opening and to be arranged orthogonally to the central longitudinal axis of the bit receptacle, and for the recess to be recessed into the bit support surface. The chisel support surface, which guarantees the exact support of the chisel as a geometrical element of the chisel holder, is not functionally impaired by the groove. The degree of depression of the groove can be optimized material selected so that the wear limit for the bit holder is reached with the processing of the entire weld.

If it is provided that the weld is flush with the bit support surface, then the weld does not affect the exact bit support and is immediately available for operation. Alternatively, it can also be provided that the weld is arranged at least partially set back relative to the bit support surface in the direction of the central longitudinal axis of the bit receptacle.

In this way, a processing of the bit on the bit holder is allowed for a limited period starting from the start of operation. This allows these components to find their working position. Thereafter or increasingly, the wear protection effect of the weld begins. Another advantage is the easy manufacturability of the weld.

In order to reliably ensure the free rotation of the bit relative to the bit holder, it may be provided that the recess rotates about the insertion opening.

A possible embodiment of the invention may be such that the groove has a bottom wall and two groove walls adjoining it laterally at an angle, and that the groove side walls are parallel to one another. Then, a constant wear resistance is opposed over the entire duration of the weld. It is also conceivable, however, that the groove has a bottom wall and two laterally adjoining each at an angle groove side walls, and that at least one of the angles is greater than 90 °, so that there is a V-shaped groove geometry, or that the groove in Cross-section is U-shaped. It can be considered that with increasing wear of the bit holder is processed. This results in changed force conditions on the bit holder, which can be taken into account with the groove geometries.

10. Darübeπhinaus has the expanding groove geometry manufacturing advantages in terms of reliable introduction of the weld.

In particular, a bit holder according to the invention may also be such that two or more grooves are incorporated into the bit support surface, which are in the middle of the bit support surface.

15 longitudinal axis of the bit receptacle concentric or rotate that the weld or welds with respect to the central longitudinal axis of the chisel receiving areas with different radial extent (-en). This measure can be counteracted by an application-related uneven wear. This effect can also be achieved, for example, with a bit holder which is such that the weld or welds have regions which occupy different radial spacings from the central longitudinal axis of the bit holder.

A possible alternative to the invention may be such that one or more grooves 5 are formed as radial grooves and arranged offset from the bit support surface.

Due to the recessed arrangement, the bit support surface remains unaffected in the fabrication of the weld. The radial groove can preferably be so ange- orders that it is visible from the outside and thus reveals the wear state as a wear marking.

The invention will be explained in more detail below with reference to exemplary embodiments illustrated in the drawings. Show it:

Figure 1 in side view a chisel holder changing system with a base part, a chisel holder and a chisel;

Figure 2 in side view and in vertical section the bit holder changing system according to Figure 1;

FIG. 3 shows the bit holder shown in FIGS. 1 and 2 in a perspective front view;

Figure 4 is an enlarged detail view of the chisel holder according to Figure 3 in side view and in section;

Figures 5 to 13 further embodiment variants of chisel holders according to Figure 3 in side view and in section;

Figures 14 and 15 are each a plan view of a bit support surface of a chisel holder according to the invention.

FIGS. 1 and 2 show a bit holder changing system with a base part 10, a bit holder 20 and a chisel 30. As can be seen from FIG. 2, the base part 10 has a shank receptacle 15 which, starting from a shoulder 12 or a bottom surface 14, is incorporated as an opening in the base part 10.

At the shoulder 12 connects at an angle to a stop surface 13. With the bottom surface 14, the base part 10 can be placed on the outer periphery of a Fräswalzenrohrs (not shown) of a road milling machine. The base part 10 is welded to the Fräswalzenrohr. In the shank receiving 15 opens against the tool feed direction, a threaded receptacle 16 into which a pressure screw 17 can be screwed.

The pressure screw 17 serves for fastening the chisel holder 20. The chisel holder 20 has an apron 21, which is integrally coupled to a connecting portion 23. The connecting portion 23 carries a lug 22 which has a projecting over the skirt 23 cylindrical portion 24. The projection 22 and the cylindrical portion 24 are penetrated by a bit holder 29 in the form of a through hole.

The cylindrical portion 24 forms at its free end a chisel support surface 26 which extends annularly and concentrically around the central longitudinal axis of the chisel receiver 29. As FIG. 2 further shows, the bit receptacle 29 merges into the bit support surface 26 via an insertion bevel 29. 2 and a centering bevel 29. The centering bevel 29.1 expands the bit receptacle 29 in a V shape. The cylindrical projection 24 carries two wear marks 25. These are pierced as annular circumferential grooves in the outer contour of the cylindrical portion 24 and held parallel spaced from the chisel support surface 26.

In the chisel support surface 26 is a cross-sectionally substantially square or rectangular recess 41 incorporated. This recess 41 can be produced by machining (drilling, turning, milling) as annular and concentric around the central longitudinal axis of the bit holder 29 circumferential groove. This groove forms a bottom surface 44, which is parallel to the chisel support surface 26. At the bottom surface 44 close at right angles groove side walls 43.1 and 43.2. In this case, the groove side walls 43.1 and 43.2 are set so that they are held at a distance from the bit holder 29 (and the Einführfase 29.2 and the centering bevel 29.1) and the wear marks 25.

This keeps these surfaces mechanically unaffected. In the recess 41, a weld 40 is introduced. This fills the recess 41 completely, wherein opposite the bottom surface 44, an open space 42 of the weld 40 is formed, which is flush with the bit support surface 26.

The recess 41 and its arrangement are chosen such that the surfaces, such as the bit receptacle 29, the insertion bevel 29. 2, the centering bevel 29. 1 and the bit support surface 26, which are particularly important for perfect initial functioning of the overall system of bit 30 and bit holder 20 are not excluded from the Weld are formed or be influenced by this functionally.

During operation, parts of the chisel holder 20 can then be worn down due to wear and the weld 40 can be exposed in areas. However, this then takes place in such a way that the weld 40 is ground so that it can take over the task of the aforementioned functional surfaces, without a tool impairment occurring. The weld outlet 40 of the opposite bore outlet of the bit holder 29 opens into a counter surface 27. In the transition region of the mating surface 27 to the skirt 21, a plug neck 28.2 is formed on the bit holder 20. With this plug-in projection 28. 2, the bit holder 20 can be inserted into the plug-in receptacle 15 of the base part 10. the. The insertion movement is limited by the stop surface 13 against which the counter surface 27 abuts.

O

To fix the chisel holder 20 in the base part 10, the pressure screw 17 is screwed into the threaded receptacle 16 until it is braced against a pressure surface 28.1 of the plug-in projection 28.2. In the mounted state, a Nachsetzraum 11 is formed between a bottom 28 of the bit holder 20 and the shoulder 12 of the base member 10.

In . the bit holder 29, a chisel 30, in this case a Ründschaftsmeißel be installed. The chisel bit has a chisel head 31 and a chisel shaft 36 formed thereon. On the chisel shaft 36, a longitudinally slotted clamping sleeve 37 is axially captive, but held radially free to rotate.

The chisel head 31 is provided with a cup-shaped receptacle in which a chisel tip 32 is attached from hard material. In the rotationally symmetrical chisel head 31, a circumferential Ausziehnut 33 is incorporated, which is bounded by a collar 34 on the shank side.

The chisel shaft 36 carries in the transition region to the chisel head 31 a wear plate 35 which is rotationally symmetrical and provided on its side remote from the chisel head 31 side with a tapered centering collar 35.1. The outer diameter and the inner diameter of the wear plate 35 and the cylindrical portion 24 are approximately equal. Likewise, the centering collar 35.1 of the wear plate 35 and the centering bevel 29.1 of the bit receptacle 29 correspond to one another in order to ensure perfect functioning, eg, in the case of a tool. As the unimpeded bit rotation, to ensure the overall system in use. The bit 30 is inserted into the bit receptacle 29 in such a way that it is held therein by means of the clamping action of the clamping sleeve 37. In this case, the wear plate 35 rests on the bit support surface 26 and the free surface 42 of the weld 40. On the opposite side of the wear plate 35 of the chisel head 31 is supported.

Due to the indispensable chisel rotation during operation, the wear plate 35 grinds over the free surface 42 and the chisel support surface 26 and works this off. It should be noted that per life cycle of a chisel 30 only minimal signs of wear occur.

In particular, the weld 40 counteracts rapid wear. Whereby the choice of welding consumables reacts to the particular wear conditions of each individual application.

Over time, however, the cylindrical portion 24 is processed, the wear state can be determined optically by the position of the bit support surface 26 with respect to the wear marking 25. After reaching the second wear marking 25 of the bit holder 20 is replaced.

FIG. 9 shows that the weld 40 concentrically revolves around the central longitudinal axis of the bit receptacle 29.

In FIG. 4, the weld 40 can be seen more clearly on an enlarged scale. The recess 41 is so far deepened in the bit holder 20 that the bottom wall 44 extends approximately to the level of the lower wear marking 25. This wear protection is guaranteed almost over the entire life of the bit holder 20. FIGS. 5 to 13 show bit holders 20 which correspond to the bit holders 20 according to FIGS. 1 to 4. They differ only with regard to the design of the recess 41 or the weld 40.

According to FIG. 5, the groove sidewalls 43.1, 43.2 of the recess 41 are set in a V-shape relative to one another, the groove sidewall 43.2 being parallel to the axis of the central longitudinal axis of the bit receptacle 29.

FIG. 6 shows a symmetrical V-shaped groove configuration, with the opening angle (setting of a groove side wall 43.1, 43.2 to the bottom wall) preferably being selected to be greater than 90 ° for particularly simple generation of the weld.

According to the exemplary embodiment in FIG. 7, two annular welds 40 that rotate concentrically around the central longitudinal axis are used. The welds 40 are formed essentially analogously to the weld 40 according to FIG.

Figure 8 illustrates an annular circumferential groove as a recess 41 which is semicircular or part-circular in cross-section. This recess 41 is particularly easy to fill with the weld 40.

While in the embodiments according to Figures 1 to 8, the free surface 42 of the weld 40 is always flush with the chisel support surface 26, Figure 9 illustrates that all welds 40 may have a respect to the chisel support surface 26 recessed free surface 42.

FIG. 10 shows a weld 40, which again takes the form of a circumferential ring. However, the ring width extending in the radial direction is varied to to form a matched to different stress intensities wear protection element.

Figures 11 and 12 show the use of recesses 41 in the form of radial grooves. These are cut radially into the cylindrical outer surface of the cylindrical portion 24.

In the embodiment according to FIG. 11, the upper groove side wall 43.1 is kept parallel spaced apart from the bit support surface 26, while the other groove side wall 43.2 is set at an angle.

In the transition region of the free surface 42 of the weld 40 to the cylindrical portion 24 are wear marks 25. If the free surface 42 is designed analogous to Figure 9, then the wear marks 25 are visible as transitions of the troughed area optically well.

FIG. 12 shows an exemplary embodiment in which two recesses 41 arranged one above the other are used with welds 40 introduced therein. As the illustration illustrates, here the welds 40 can form outwardly projecting free surfaces 42 for identifying wear marks 25.

In the figure 13 an embodiment is shown, which illustrates that the recess 41 may be formed not only in the form of a groove, but also as a recess.

Instead of circumferential welds 40, it is also possible for punctiform, curved or linear recesses 41 with welds 40 to be provided, as shown by way of example in FIGS. 14 and 15. Only restriction for the The shape and arrangement of the recess (s) is that they are to be finished and refilled with the weld.

The invention described can be used not only in the chisel holders 20 shown in the drawings, but in chisel holders 20 of any desired shape and easy to implement.

Claims

A chisel holder (20) for a cutting machine, road milling machine, surface miner or the like having a bit receptacle (29) having an insertion opening and a bit support surface (26), at least one wear protection element (40) in an area associated with the bit support surface (26) ) is arranged, characterized in that the at least one wear protection element as a weld (40) and formed at least partially in at least one recess

(41) is arranged.

2. bit holder according to claim 1, characterized in that the recess (41) is formed as a groove.

3. bit holder according to claim 1 or 2, characterized in that the bit support surface (26) rotates annularly around the insertion opening and orthogonal to the central longitudinal axis of the bit receptacle (29) is arranged, and that the recess (41) in the bit support surface (26) is.

4. bit holder according to claim 3, characterized in that the weld (40) is flush with the bit support surface (26).

5. bit holder according to claim 3, characterized in that the weld (40) relative to the bit support surface (26) in the direction of the central longitudinal axis of the bit receptacle (29) is arranged at least partially set back.

6. bit holder according to one of claims 1 to 5, characterized in that the recess (41) rotates about the insertion opening.

7. bit holder according to one of claims 2 to 6, characterized in that the groove has a bottom surface 44 and two laterally thereto at an angle subsequent groove walls (43.1, 43.2), and that the groove side walls (43.1, 43.2) are parallel to each other.

8. bit holder according to one of claims 2 to 6, characterized in that the groove has a bottom surface 44 and two laterally thereto in each case in one

Angle adjoining groove side walls (43.1., 43.2), and that at least one of the angles is greater than 90 °, so that there is a V-shaped groove geometry, or that the groove is formed in cross-section U-shaped.

9. bit holder according to one of claims 1 to 8, characterized in that in the bit support surface (26) two or more grooves are incorporated, the concentric to the central longitudinal axis of the bit holder (29) umlauf.

10. bit holder according to one of claims 1 to 9, characterized in that the weld (40) or the welds (40) relative to the central longitudinal axis of the bit receptacle (29) has areas with different radial extent (-en).

11. bit holder according to one of claims 1 to 10, characterized in that the weld (40) or the welds (40) has regions (s), which occupy different radial distances to the central longitudinal axis of the bit holder (29).

12. bit holder according to one of the preceding claims, characterized in that one or more grooves formed as radial grooves and with respect to the bit support surface (26) are set back.

13. bit holder according to claim 12, characterized in that the introduced into the groove or in the grooves welds (40) form wear marks.