Tracked chassis and work machine having a track drive

Abstract

A tracked chassis for a working machine has a track which includes at least one roller path, preferably two roller paths extending in parallel, on whose running surface at least one plain roller of the tracked chassis is movable during crawler operation. The running surface of at least one roller path of the track and the running surface of at least one roller have a transverse section with an at least sectionally convex contour.

Claims

1. A tracked chassis for a work machine having a track which comprises a roller path on whose running surface at least one roller of the tracked chassis is movable during crawler operation, wherein the running surface of the roller path of the track has a recess (25), the running surface of the at least one roller has a flange (30) received in the recess (25) and the running surfaces of the roller path and at least one roller each have a transverse section on opposite sides of the respective flange (30) and recess (25) and having a convex or concave contour immediately adjacent the respective flange (30) and recess (25), an outermost convex contour, and being straight between the outermost contour and the contour immediately adjacent the respective flange (30) and recess (25).

2. The tracked chassis in accordance with claim 1, wherein the running surface of the roller path of the track at an inner marginal region of the transverse section has a convex contour and the running surface of the roller has a convex contour at an outwardly disposed marginal region of the transverse section.

3. The tracked chassis in accordance with claim 1, wherein the convex contour of the roller and/or of the track is arcuate and/or complex arcuate.

4. A tracked chassis for a work machine having a track which comprises a roller path on whose running surface at least one roller of the tracked chassis is movable during crawler operation, wherein the running surface of the roller path of the track and the running surface of the at least one roller have a transverse section with a sectionally convex contour, and the length R.sub.Horizontal of the transverse section of the surface of the at least one roller is composed of a linear portion R2.sub.Horizontal and a convex portion R3.sub.Horizontal, where the following formula applies: $\frac{1}{10}.Math.R_{\mathrm{Horizontal}}<R{2}_{\mathrm{Horizontal}}<\frac{9}{10}.Math.R_{\mathrm{Horizontal}}\mathrm{where}$ $R{3}_{\mathrm{Horizontal}}=R_{\mathrm{Horizontal}}-R{2}_{\mathrm{Horizontal}}.$

5. The tracked chassis in accordance with claim 4, wherein due to the convex contour of the convex portion R3.sub.Horizontal, a height offset R3.sub.Vertical of the transverse section R.sub.Horizontal at a margin side results with respect to the linear contour R2.sub.Horizontal of the transverse section R.sub.Horizontal, where the following formula applies: $\frac{1}{500}.Math.R_{\mathrm{Horizontal}}<R{3}_{\mathrm{Vertical}}<\frac{1}{10}.Math.R_{\mathrm{Horizontal}}.$

6. A tracked chassis for a work machine having a track which comprises a roller path on whose running surface at least one roller of the tracked chassis is movable during crawler operation, wherein the running surface of the roller path of the track and the running surface of the at least one roller have a transverse section with a sectionally convex contour, and the length P.sub.Horizontal of the transverse section of at least one running surface of the track is composed of a linear portion P3.sub.Horizontal and a convex portion P2.sub.Horizontal, where the following formula applies:
P3.sub.Horizontal=P.sub.HorizontalP2.sub.Horizontal.

7. The tracked chassis in accordance with claim 6, wherein due to the convex contour of the convex portion P2.sub.Horizontal, a height offset P2.sub.Vertical of the transverse section P.sub.Horizontal at a margin side results with respect to the linear contour P3.sub.Horizontal of the transverse section P.sub.Horizontal, where the following formula applies: $\frac{1}{500}.Math.P_{\mathrm{Horizontal}}<P{2}_{\mathrm{Vertical}}<\frac{1}{10}.Math.P_{\mathrm{Horizontal}}.$

8. The tracked chassis in accordance with claim 6, wherein the following applies to the relationships of the running surface of the track and of the running surface of the roller:
P.sub.HorizontalR.sub.Horizontal,
P2.sub.HorizontalR2.sub.Horizontal.

9. The tracked chassis in accordance with claim 1, wherein at least one running surface of the track is divided into a plurality of running surface segments having a linear portion in the transverse direction, with convex portions adjoining the linear portions at both sides.

10. The tracked chassis in accordance with claim 1, wherein the at least one roller comprises a center flange for guiding the plain roller on the track, with side flanks of the center flange having a convex contour at least sectionally in the radial direction.

11. The tracked chassis in accordance with claim 10, wherein a flank section has a contour alternating linearly and convexly in the radial direction.

12. The tracked chassis in accordance with claim 11, wherein each said side flank comprises at least two linear sections which are separated by at least one convex part, with the linear portions having different angles of inclination with respect to the vertical, between 0 and 50 or 0 and 30, and with the linear portion disposed closer to the center flange dome having a greater inclination.

13. The tracked chassis in accordance with claim 12, wherein at least one running surface of the track is divided into a plurality of running surface segments having a linear portion in the transverse direction, with convex portions adjoining the linear portions at both sides, and the oppositely disposed side wall of the recess of the track receiving the center flange has a convex contour at least sectionally and is composed of a linear portion and a convex portion.

14. The tracked chassis in accordance with claim 13, wherein the linear portion of the side wall of the recess is inclined with respect to the vertical, at an identical angle to the oppositely disposed linear portion of the side flank of the center flange.

15. A crawler excavator or a crawler-mounted crane, having the tracked chassis in accordance with claim 1.

16. A tracked chassis for a work machine having a track which comprises a roller path on whose running surface at least one roller of the tracked chassis is movable during crawler operation, wherein the running surface of the roller path of the track and the running surface of the at least one roller have a transverse section with a sectionally convex contour, the running surface of the roller path of the track at an inner marginal region of the transverse section has a convex contour and the running surface of the roller has a convex contour at an outwardly disposed marginal region of the transverse section, and the convex contour of the roller and/or of the track is arcuate and/or complex arcuate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages and properties of the invention will be explained in more detail in the following with reference to an embodiment shown in the drawings. There are shown:

(2) FIG. 1: a side view of the tracked chassis in accordance with the invention;

(3) FIG. 2: a sectional representation through the tracked chassis of FIG. 1 in the region of the contact surface between the plain roller and the track link;

(4) FIG. 3: a contour sketch of the running surfaces of the roller and of the track;

(5) FIG. 4: a sketch of the running surface contour of the track;

(6) FIG. 5: a sketch of the running surface contour of the plain roller;

(7) FIGS. 6A-6C: various sketches of the running surface contours under differ ent operating conditions, with FIG. 6A showing a cross-section through the contact surface of the roller and track link, FIG. 6B showing the cross-section where the roller is laterally offset on the track link, and FIG. 6C showing the center flange of the roller displaced to the left and the track pressed upwardly towards the roller at the left;

(8) FIGS. 7A-7D: an overview of possible track designs of a tracked chassis, with FIG. 7A showing an asymmetrical design of roller paths, FIG. 7B showing a symmetrical design of roller paths, FIG. 7C showing a modified symmetrical design of roller paths, and FIG. 7D showing a top plan view of a possible track design;

(9) and

(10) FIG. 8: an alternative embodiment of a track link with divided running surfaces.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(11) FIG. 1 shows a side view of the crawler drive in accordance with the invention for an earth-moving machine or a crawler-mounted crane. The crawler drive shown is fastened to the undercarriage of the work machine and serves the locomotion of the machine.

(12) The chassis design comprises a driven sprocket wheel 4 which is driven via a drive mounted at the undercarriage and suitable for the locomotion. The idler 1 over whose periphery the crawler track runs is located at the end of the crawler drive at the left in the illustration. The idler 1 provides sufficient tensioning of the track, which is achieved by the movable support of the idler 1 at the undercarriage. The crawler track runs on the tension rollers 5 mounted at the upper edge of the superstructure to support the track sufficiently and to avoid sag.

(13) A total of six plain rollers 3 are provided close to the ground along the contact area to introduce the machine weight, loads (e.g. equipment forces) or the contact pressure evenly over the contact area into the ground. In the embodiment shown, the plain rollers 3 are fastened at equal intervals between the sprocket wheel 4 and the idler 1; differences in the number and also with respect to the spacings of the plain rollers 3 from one another are easily conceivable. The crawler track is composed of individual track links 2 which are bolted together in an articulated manner via bolt connections.

(14) FIG. 2 shows a sectional representation of an individual plain roller 3 transversely to the running direction which runs off on a track link 2. Two separate running surfaces 31, 32 of the plain roller 3 can be recognized having the same diameter and an identical surface width. Both running surfaces 31, 32 run over the inner side of the individual track links 2 during the vehicle locomotion, that is they are carried by defined running surfaces 21, 22 on the inner side of the track links 2.

(15) The center flange 30 of the plain roller 3 serves for forming of a guide wheel having a diameter increased in size with respect to the running surfaces 31, 32. The center flange engages into the recess 25 of the track link 2 which is continuous in the longitudinal direction and ensures a sufficient guidance of the roller 3 on the track by means of its side flanks 33, 34 which abut the side walls 23, 24 of the recess 25.

(16) The present invention now describes a suitable modification of the running surface sections as well as optionally of the flanks 33, 34 or side wall contours 23, 24 to minimize loads for the track and the plain rollers 3 as much as possible. The modification of the running surface contours will be explained in the following with reference to the representation in FIG. 3 which sketches a part of the right hand running surface 31 of the plain roller 3 and the associated running surface 21 of the track link 2.

(17) The transverse section of the track link 2, i.e. the total width of the running surface 21 transverse to the running direction will be termed P.sub.Horizontal in the following. This running surface is divided into a linear portion P3.sub.Horizontal, i.e. a portion having a straight-line surface contour, and a convex portion P2.sub.Horizontal, i.e. a portion with a convex contour extent. The convex portion P2.sub.Horizontal takes up the left hand marginal region of the total running surface P.sub.Horizontal and is consequently adjacent to the recess 25. The resulting running surface 21, i.e. the total width of the transverse section P.sub.Horizontal consequently corresponds to the sum of the linear portion and the convex portion P2.sub.Horizontal+P3.sub.Horizontal.

(18) It can furthermore be recognized that, due to the convex portion P2.sub.Horizontal, a height offset of the running surface results with respect to the linear portion P3.sub.Horizontal, which adopts a value of P2.sub.Vertical. The maximum value P2.sub.Vertical is consequently present at the inner end of the convex portion P2.sub.Horizontal. The transition of the transverse section P.sub.Horizontal into the side wall 23 takes place over a rounded corner having a constant radius whose transverse length is designated by P1.sub.Horizontal. The same applies to the outer edge of the running surface 21 having the transverse length P4.sub.Horizontal. The regions P4.sub.Horizontal and P1.sub.Horizontal can alternatively also be configured as convex, in particular as arcuate or in the manner of a basket bottom. The hatched region represents the permitted radius range of the convex portion P2.sub.Horizontal. The convex portion P2.sub.Horizontal can comprise a constant radius, be of a complex shape/arc-like shape.

(19) FIG. 3 furthermore shows the contour section of the running surface 31 of the plain roller 3 running off on the described running surface. This transverse section R2.sub.Horizontal is also composed of a linear portion R2.sub.Horizontal and a convex portion R3.sub.Horizontal. The convex portion is in this respect provided at the outer marginal region of the transverse section R.sub.Horizontal. The likewise resulting height offset of the transverse section is designated by the value R3.sub.Vertical which is measured at the outer end region of the convex section R3.sub.Horizontal. As with the track link 2, the transition to the outer side flank 35 is also rounded; the transverse length of the rounding is designated as R4.sub.Horizontal. The transition of the linear portion R2.sub.Horizontal to the side flank 33 of the center flange takes place with a constant radius, with the transverse length of the transition being designated by R1.sub.Horizontal. The parallel running surfaces 22, 32 are axially symmetrical. The regions R4.sub.Horizontal and R1.sub.Horizontal can alternatively also be configured as convex, in particular as arcuate or complex arcuate. The hatched region represents the permitted radius range of the convex portion R3.sub.Horizontal. The convex portion R3.sub.Horizontal can comprise a constant radius and be of a complex shape/arc-like shape The plain roller is preferably axially symmetrical, at least with respect to the configuration of the center flange 30 and of the running surfaces 31, 32.

(20) The dimensioning of the linear portions or convex portions of the respective running surfaces 21, 22, 31, 32 is fixed by the following formulas:

(21) $\frac{1}{10}.Math.R_{\mathrm{Horizontal}}<R{2}_{\mathrm{Horizontal}}<\frac{9}{10}.Math.R_{\mathrm{Horizontal}}$$R{3}_{\mathrm{Horizontal}}=R_{\mathrm{Horizontal}}-R{2}_{\mathrm{Horizontal}}$$\frac{1}{500}.Math.R_{\mathrm{Horizontal}}<R{3}_{\mathrm{Vertical}}<\frac{1}{10}.Math.R_{\mathrm{Horizontal}}$$P_{\mathrm{Horizontal}}{R}_{\mathrm{Horizontal}}$$P{2}_{\mathrm{Horizontal}}R{2}_{\mathrm{Horizontal}}$$P{3}_{\mathrm{Horizontal}}=P_{\mathrm{Horizontal}}-P{2}_{\mathrm{Horizontal}}$$\frac{1}{500}.Math.P_{\mathrm{Horizontal}}<P{2}_{\mathrm{Vertical}}<\frac{1}{10}.Math.P_{\mathrm{Horizontal}}$$R{1}_{\mathrm{Horizontal}}20\mathrm{mm}$$R{4}_{\mathrm{Horizontal}}20\mathrm{mm}$$P{1}_{\mathrm{Horizontal}}20\mathrm{mm}$$P{4}_{\mathrm{Horizontal}}20\mathrm{mm}$

(22) In accordance with the present invention, however, not only the running surfaces 21, 22, 31, 32 are to be modified, but also the contour of the center flange 30 of the plain roller 3 and of the corresponding recess 25 of the track link 2.

(23) In FIG. 4, P.sub.M denotes a central plane or line within the link 2, with P.sub.g denoting the central portion encompassed by recess 25 and P.sub.RP and P.sub.RP denoting lateral portions of respective running surfaces 22 and 21 on either side of recess 25. P.sub.4 denotes the transition region on the opposite outer side of link 2 from transition region P.sub.1. In FIG. 5, R.sub.M denotes a central plane or line within the roller 3, with R.sub.g denoting the central portion encompassed by central flange 30 and R.sub.RP and R.sub.RP denoting lateral portions of respective running surfaces 32 and 31 on either side of central flange 30. R.sub.4 denotes the corner on the opposite outer side of roller 3 from corner R.sub.1.

(24) The specific shape of the side flank of the recess 25 can be seen from FIG. 4. For reasons of simplicity, the index horizontal was omitted in the Figure representation. It can be recognized in this respect that a linear portion P6, which opens into the base of the recess 25 over the curved region, adjoins the transition region P1 of the convex portion P2 to the side wall 23. The region P7 can likewise be a curve with a constant radius or can have a complex arcuate design. The linear portion P6 is inclined at an angle P.sub. with respect to the vertical 50.

(25) The side flank 33 of the center flange 30 of the plain roller 3 is shown in FIG. 5. The linear portion R2 of the running surface 3 merges over the rounded corner R1 into a linear portion R6 of the side flank 33 of the center flange 30. A first convex portion R7 adjoins the linear portion R6; it again merges into a linear portion R8 and finally ends in the convex portion R9 which directly adjoins the dome of the center flange 30. The convex regions R6, R8 can also have a constant radius of curvature or can also be of an arcuate design.

(26) It can furthermore be recognized that the linear portions R6, R8 adopt different angles of inclination R.sub., R.sub. with respect to a vertical 50. The angle of inclination R.sub. of the linear portion R6 is selected to be smaller than the angle of inclination R.sub. of the linear portion R8. Rules for the dimensioning of the corresponding angle of inclination were fixed as follows:
0<R.sub.<30
0<R.sub.<50

(27) The angle of inclination P.sub. of the side part 23 of the track link 2 is typically dimensioned equal in amount to the angle of inclination R.sub. of the plain roller 3.

(28) An understanding of the advantageous characteristic operating properties of the modified contour of the plain roller 3 and of the track link 2 will be given with reference to the Figure representations 6a, 6b, 6c. The representation of FIG. 6a shows a cross-section through the contact surface of the roller 3 and of the track link 2. The plain roller 3 in this respect lies centrally on the track link 2, i.e. the center flange 30 engages centrally into the recess 25.

(29) The following statements are made for the example of the running surfaces 21, 31 and apply equally to the running surfaces 22, 32 due to the axially symmetrical design of the track link 2 or of the plain roller 3. The main contact surface between the plain roller 3 and the track link 2 is achieved by the contacting of both linear portions R2, P3. The spacing between the two running surfaces is increased in these regions by the convex portions R3, P2. An optimum contact surface between the two components thereby results which allows an optimum flow of forces. The occurrence of load peaks at points can consequently be avoided.

(30) FIG. 6b shows an operating situation in which the plain roller 3 lies laterally offset on the track link 2. The right hand side flank 33 of the center flange 30 thereby contacts the side wall 23 of the recess 25. Furthermore, due to external influences, the track is pressed upwardly on the side shown at the right in the drawing so that the plain roller 3 runs obliquely on the track and the left hand running surface 32 rises from the running surface 22 of the track link. Due to the contour modification in accordance with the invention with the convex portions P2, R3, the running surface 31 can roll off to the right on the running surface 21 without load peaks arising on the running surface 21. The convex portion R3 contacts the linear portion P3 of the track link 2. The specific dimensioning of the convex portion R3 is selected in this respect such that the resulting contact pressure does not exceed or only slightly exceeds the regular contact pressure of the operation situation in accordance with FIG. 6a.

(31) In FIG. 6c, the center flange 30 is displaced to the left and the track is pressed upwardly in the direction of the plain roller 3 at the left hand side due to the characteristic at the site of use. The convex contour of the two running surfaces 21, 31 also provides a uniform load and contact here; the plain roller is in contact with the convex portion P2 of the track link 2 by means of the linear portion R2.

(32) The plain roller 3 can optionally completely lose contact with the track link 2 during working operation. The specific embodiment of the region R8, in particular the more acute tapering of the center flange 30 due to the larger angle of inclination R.sub. of the center flange 30 allows a reliable new engagement of the center flange 30 in the recess 25. At the start of the engagement, the region R8 contacts the region P1 of the track link.

(33) A further advantage of the embodiment in accordance with the invention comprises the fact that the linear portions P6 and R6 of the track link 2 or of the plain roller 3 are in parallel with one another and thus allow an areal contact between the center flange and the side wall of the recess 25. The wear which occurs in this region can thereby be further limited.

(34) FIG. 7 shows different track designs in which the roller paths 21, 22 extending in parallel are composed of individual track links 2 in different manners. FIG. 7a shows an asymmetrical design of the roller paths of a single track link 2. It is thereby achieved that the transition gaps between individual track links 2 lie offset in the longitudinal direction to reduce vibrations during the rolling-off of the roller 3. FIG. 7b shows a symmetrical design with symmetrical or identical track links 2. The variant of FIG. 7c shows a slight modification with respect to the symmetrical design of FIG. 7b. In this respect, the individual running surfaces 21, 22 of an individual track link are admittedly of identical design, but are slightly offset in the running direction to realize the aforesaid advantages of the asymmetrical design. However, the resulting wear at the track links 2 can be considerably reduced for all variants of FIGS. 6a to 6c by means of the contour modification in accordance with the invention.

(35) FIG. 8 shows a further embodiment whose running surface is divided into two or more running surface segments P.sub.RP1 to P.sub.RPX. The running surface 31 of the plain roller 3 then rolls off simultaneously on two or more roller paths P.sub.RP1, P.sub.RP2, P.sub.RPX. The linear portion of the running surface 21 is divided in this case in linear portions P.sub.31, P.sub.32, P.sub.3X of the running surface segments P.sub.RP1 to P.sub.RPX. Convex portions P.sub.2, P.sub.RP12, P.sub.RP21, . . . , P.sub.RPX2, P.sub.RPX1, P.sub.4 adjoin at both sides of the linear portions of a running surface segment.