Interchangeable unit for texturing ground surface work and road construction machine having such an interchangeable unit

Abstract

The present invention relates to an interchangeable unit (28) for material-removing work on a subsoil (U) starting from ground surface (A), the interchangeable unit (28) being designed for operational physical and functional coupling to a machine frame (12) of a road construction machine (10), the interchangeable unit (28) comprising: a housing (30), a removal tool (32), which is mounted on the housing (30) so as to be rotatable about a working axis (R) and of which a circumferential section protrudes from a working opening (30c), a drive belt pulley (62), which is rotatably mounted on the housing (30) and is able to be coupled to a drive belt (58), a transmission gear unit (76), which transmits torque and rotary motion from the drive belt pulley (62) to the removal tool (32) by reversing the direction of rotation, at least the axis of rotation (P62) of the drive belt pulley (62) running at a distance from the working axis (R).

According to the invention, a working shaft assemblage (74) penetrates a housing wall (30d) of the housing (30), the working shaft assemblage (74) connecting the removal tool (32) with a working gear component (70) situated on the side of the housing wall (30d) facing away from the removal tool (32) for equidirectional joint rotation, the transmission gear unit (76) being situated between the drive belt pulley (62) and the working gear component (70).

Claims

1-18. (canceled)

19. An interchangeable unit for removing material from a ground surface, the interchangeable unit being configured for operational physical and functional coupling to a machine frame of a road construction machine, the interchangeable unit comprising: a housing including: a connecting section configured to physically couple the interchangeable unit to the road construction machine, the connecting section including a plurality of connecting configurations configured to mount the interchangeable unit to the machine frame of the road construction machine; and a working section including a working opening, the working section located remotely from the connecting section; a removal tool, mounted to the housing and rotatable about a working axis such that a circumferential section of the removal tool protrudes from the working opening; a drive belt pulley rotatably mounted on the housing and configured to be coupled to a drive belt for functionally coupling the interchangeable unit to the road construction machine, the drive belt pulley including an axis of rotation spaced from the working axis of the removal tool; a transmission gear unit configured to transmit torque and rotary motion from the drive belt pulley to the removal tool; a start-up motor; and a start-up clutch configured to connect the start-up motor and the removal tool in a torque-transmitting fashion such that the start-up motor is disengageable from the removal tool.

20. The interchangeable unit of claim 19, wherein: the transmission gear unit includes an intermediate belt pulley; and the start-up clutch is configured to connect the start-up motor to one of the drive belt pulley or the intermediate belt pulley.

21. The interchangeable unit of claim 19, further comprising: a controller configured to switch the start-up clutch into a, or hold the start-up clutch in a, torque-transmitting connection state if the removal tool rotates at a speed that is lower than or equal to a first limit speed, the first limit speed being lower than a removal speed of the removal tool during normal removal operation of the removal tool.

22. The interchangeable unit of claim 21, wherein: the controller is further configured to switch a drive belt tensioner into an, or hold the drive belt tensioner in an, operating state such that a belt tension of the drive belt is at an idling tension when the removal tool rotates at a speed lower than a second limit speed, the idling tension being lower than an operating tension of the drive belt during normal removal operation of the removal tool, and the second limit speed being lower than or equal to the first limit speed.

23. The interchangeable unit of claim 22, wherein: the controller is further configured to change the belt tension of the drive belt such that the belt tension of the belt drive is between the idling tension and the operating tension, the change in the tension of the drive belt corresponding to the change of the speed of the removal tool between the second limit speed and the removal speed.

24. The interchangeable unit of claim 19 in combination with the road construction machine, wherein: the road construction machine includes: the machine frame; a traveling gear including at least three drive units configured to rollably stand on the ground surface; a motor including an output shaft configured to provide torque; an output belt pulley drivable by the motor; a plurality of counterpart configurations engaged with the plurality of connecting configurations for mounting the interchangeable unit to the machine frame of the road construction machine; and the drive belt connecting the output belt pulley to the drive belt pulley in torque-transmitting fashion.

25. The interchangeable unit in combination with the road construction machine as recited in claim 24 further comprising: a controller configured to: switch the start-up clutch into a, or hold the start-up clutch in a, torque-transmitting connection state if the removal tool rotates at a speed that is lower than or equal to a first limit speed, the first limit speed being lower than a removal speed of the removal tool during normal removal operation of the removal tool; switch a drive belt tensioner into an, or hold the drive belt tensioner in an, operating state such that a belt tension of the drive belt is at an idling tension when the removal tool rotates at a speed lower than a second limit speed, the idling tension being lower than an operating tension of the drive belt during normal removal operation of the removal tool, and the second limit speed being lower than or equal to the first limit speed; and change the belt tension of the drive belt such that the belt tension of the belt drive is between the idling tension and the operating tension, the change in the tension of the drive belt corresponding to the change of the speed of the removal tool between the second limit speed and the removal speed.

26. The interchangeable unit of claim 19, wherein: the start-up motor and the start-up clutch are located within the housing of the interchangeable unit.

27. The interchangeable unit of claim 19, wherein: the start-up motor is an electric motor.

28. The interchangeable unit of claim 19, wherein: the start-up motor is a hydraulic motor.

29. A method of starting up a removal tool of an interchangeable unit of a road construction machine: wherein the interchangeable unit includes: a housing; a removal tool mounted on the housing; a drive belt pulley rotatably mounted on the housing; a transmission gear unit configured to transmit torque and rotary motion from the drive belt pulley to the removal tool; a start-up motor; and a start-up clutch configured to connect the start-up motor and the removal tool in a torque-transmitting fashion such that the start-up motor is disengageable from the removal tool; wherein the road construction machine includes: a machine frame, the housing being mounted to the machine frame; at least three drive units configured to rollably stand on a ground surface; a motor; an output belt pulley drivable by the motor; and a drive belt connecting the output belt pulley to the drive belt pulley; the method comprising: switching the start-up clutch into a, or holding the start-up clutch in a, torque-transmitting connection state if the removal tool rotates at a speed that is lower than or equal to a first limit speed, the first limit speed being lower than a removal speed of the removal tool during normal removal operation of the removal tool.

30. The method of claim 29, further comprising: switching a drive belt tensioner into an, or holding the drive belt tensioner in an, operating state such that a belt tension of the drive belt is at an idling tension when the removal tool rotates at a speed lower than a second limit speed, the idling tension being lower than an operating tension of the drive belt during normal removal operation of the removal tool, and the second limit speed being lower than or equal to the first limit speed.

31. The method of claim 30, further comprising: changing the belt tension of the drive belt such that the belt tension of the belt drive is between the idling tension and the operating tension, the change in the tension of the drive belt corresponding to the change of the speed of the removal tool between the second limit speed and the removal speed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0079] FIG. 1 a rough schematic lateral view in the transverse direction of the machine frame of a road construction machine of the present invention in the exemplary form of a large milling machine, the machine frame of the road construction machine being connected to an interchangeable unit of the present invention.

[0080] FIG. 2 a rough schematic top view onto a gear wheel transmission stage on the interchangeable unit of the road construction machine from FIG. 1.

[0081] FIG. 3 a rough schematic perspective view of the interchangeable unit of the road construction machine from FIG. 1 shown in isolation.

DETAILED DESCRIPTION

[0082] The viewer of FIG. 1 is looking onto the only schematically drawn road construction machine or simply “machine” 10 in the direction of the transverse machine frame direction Q which is orthogonal to the drawing plane of FIG. 1. The longitudinal machine frame direction is labeled L and extends parallel to the drawing plane of FIG. 1. The vertical machine direction H runs likewise parallel to the drawing plane of FIG. 1 and orthogonal to the longitudinal machine direction L and the transverse machine direction Q. The arrowhead of longitudinal machine frame direction L in FIG. 1 points in the forward direction. Vertical machine frame direction H is parallel to the extension direction of lifting columns 14 and 16. Vertical machine direction H extends parallel to the yaw axis G.sub.i of machine 10, longitudinal machine direction L extends parallel to the roll axis R.sub.o, and transverse machine direction Q extends parallel to pitch axis N.sub.i.

[0083] Road construction machine 10 may comprise an operator's platform 24, from which a machine operator is able to control machine 10 via a control panel 26. Control panel 26 may accommodate a controller 27 of road construction machine 10, which is operated from control panel 26 and which through control interventions of an operator and/or on the basis of preprogrammed control program sequences controls the switching operations and work operations on road construction machine 10 mentioned in the present application. For this purpose, controller 27 comprises at least one integrated circuit and a data memory connected to the latter in data-transmitting fashion.

[0084] Below machine frame 12, an interchangeable unit 12 is indicated merely by dashed lines and only in FIG. 1, in this case by way of example as device 28 for texturing ground surfaces using groove cutting drum 32 accommodated in a housing 30 of interchangeable unit 28, which extends along the transverse machine frame direction Q and is rotatable about a working axis R extending in the transverse machine frame direction Q in order thereby to be able to cut grooves into ground material starting from the contact surface A of the ground U to a cutting depth determined by the relative vertical position of machine frame 12. Such grooving-texturing surface work may be used to reduce the generation of rolling noises on the contact surface A and/or to ensure a defined drainage of precipitation and/or to increase the quantity of precipitation removable per unit of time. The groove cutting drum 32 may include a plurality of circular diamond-impregnated saw blades and is sometimes referred to as a grinder or a grinding head.

[0085] The vertical adjustability of machine frame 12 by way of lifting columns 14 and 16 therefore also serves to set the cutting depth, or generally working depth, of machine 10 when working the ground. Earth working machine 10 depicted by way of example is a large road milling machine, for which the placement of interchangeable unit 28 between the front and rear drive units 18 and 20 in longitudinal machine frame direction L is typical. Large road milling machines of this kind, or indeed ground-removing machines in general, usually comprise a transport belt in order to transport removed ground material away from machine 10. In the interest of better clarity, a transport belt that is also present in principle in the case of machine 10 is not depicted in FIG. 1. Furthermore, due to the small quantity of removed ground material in comparison with milling work, no transport belt is required for the present surface-texturing ground work, for which the road construction machine 10 depicted in FIG. 1 is currently equipped. The removed material is bound by water and is suctioned off from housing 30, which is advantageously under negative pressure.

[0086] It is not apparent from the lateral view of FIG. 1 that machine 10 comprises, in both its front end region and its rear end region, two respective lifting columns 14 and 16 each having a drive unit 18, 20 connected to it. Lifting columns 14 are coupled to drive unit 18 by a coupling structure 34 in a manner known per se. Rear lifting columns 16 are connected to their respective drive unit 20 via a coupling structure 36 constructed identically to coupling structure 34. Drive units 18 and 20 are of substantially identical construction and constitute traveling gear 22 of the machine.

[0087] In the example depicted, drive unit 18, having a possible travel direction indicated by double arrow D, comprises a radially inner accommodation structure 38 on which a circulating drive track 40 is arranged. In a departure from the depicted crawler track units 18 and 20, drive units 18 and/or 20 may also be designed as wheel drive units.

[0088] Each of lifting columns 14 and 16, and along with these drive units 18 and 20, is respectively rotatable about a steering axis S by way of a steering apparatus (not further depicted).

[0089] Interchangeable unit 28 is exchangeable for an interchangeable milling unit. For most of the time of its removal operation, road construction machine 10 carries an interchangeable milling unit comprising a milling drum. The interchangeable unit 28 depicted in rough schematic fashion in FIG. 1, for grooving surface work by way of example, makes it possible to expand the spectrum of work that road construction machine 10 is able to perform. By installing the interchangeable unit 28 including the grooving-cutting drum 32 supported therein, the large road milling machine 10, which hitherto merely performed milling work, becomes also surface-texturing road construction machine 10.

[0090] On its side facing machine frame 12, housing 30 has a connecting section 30a, by which interchangeable unit 28 is connected to machine frame 12. As connecting configurations 42, connecting section 30a has mounting links 44 having through-holes 47 (see FIG. 3), which in the depicted example are penetrated by threaded bolts 46. Threaded bolts 46 also penetrate connecting counterpart configurations 48 of machine frame 12, which likewise have through-holes. Like connecting configurations 42, connecting counterpart configurations 48 are also developed as mounting links 50 for better access for workers who insert and tighten threaded bolts 46. The number of mounting links 44 and 50 as well as threaded bolts 46 may and normally will deviate from the number depicted in FIG. 1.

[0091] In its lower end region opposite from connecting section 30 along yaw axis G.sub.i, housing 30 or interchangeable unit 28 has a working section 30b having a working opening 30c, through which grooving-cutting drum 32 protrudes in order to make material-removing contact with ground U.

[0092] Supported on machine frame 12, an internal combustion engine 52 having a crankshaft 53 extending along pitch axis N.sub.i as a motor output shaft is indicated by dashed lines on road construction machine 10, crankshaft 53 being coupled on the output side to a preferably switchable pump transfer gear 54, which is likewise indicated only in rough schematic fashion by dashed lines. A gear output shaft 55 of pump transfer gear 54, which is coaxial with respect to the axis of rotation of crankshaft 53, supports an output belt pulley 56, which rotates about an output belt pulley axis P56 that is parallel to pitch axis N.sub.i. The pump transfer gear 54 may also be referred to as a pump gear drive 54.

[0093] Using the drive force of motor 52 transmitted to it by pump transfer gear 54, output belt pulley 56 drives a revolving drive belt 58, which is able to be tensioned by variable tensional force via a drive belt tensioner 60. For this purpose, drive belt tensioner 60 has a tensioning roller 60a abutting against the inner circumference of drive belt 58, which is displaceable via a piston-cylinder assemblage 60b as actuator against the inner circumference of drive belt 58 and away from the latter. Changing the tension of drive belt 58 makes it possible to change the force transmittable from output belt pulley 56 to drive belt 58 and thereby change the torque maximally transmittable by drive belt 58.

[0094] For retooling road construction machine 10 in a precisely targeted manner, road construction machine 10 may carry along a further output belt pulley 56′ in a storage space 57, which is exchangeable for the output belt pulley 56 active in FIG. 1, if required. The further output belt pulley 56′ has a different diameter than output belt pulley 56.

[0095] Drive belt 58 transmits torque onto a drive belt pulley 62 situated on interchangeable unit 28, which rotates about a drive belt pulley axis P62 extending parallel to pitch axis N.sub.i. Drive belt pulley 62 is connected to a gear wheel transmission stage 64 (not shown in detail in FIG. 1), which transmits torque from drive belt pulley 62 to an intermediate belt pulley 66. Each belt pulley 62 and 66 is coupled respectively to one gear wheel of gear wheel transmission stage 64 comprising an even number of pairwise mutually meshing gear wheels so that the direction of rotation is reversed in the transmission of torque from drive belt pulley 62 to intermediate belt pulley 66. Intermediate belt pulley 66 therefore rotates in the opposite direction as drive belt pulley 62. Intermediate belt pulley 66 rotates about an intermediate belt pulley axis P66 that is parallel to pitch axis N.sub.i and thus also to working axis R.

[0096] Intermediate belt pulley 66 drives a working belt 68, which runs at a distance from intermediate belt pulley 66 about a working belt pulley 70. Working belt 68 is tensionable by a working belt tensioner 72 in the same manner as drive belt 58 is tensionable by drive belt tensioner 60. Working belt tensioner 72 is structurally designed like drive belt tensioner 60.

[0097] Working belt pulley 70 rotates about a working belt pulley axis P70 that is coaxial to working axis R. In the depicted example, working belt pulley 70 is rigidly connected to grooving-cutting drum 32 via a working shaft assemblage 74 formed by a single working shaft 73 and transmits the torque received from intermediate belt pulley 66 directly and immediately in the same direction to grooving-cutting drum 32. Working shaft 73 and therewith working shaft assemblage 74 penetrate lateral wall 30d of housing 30. The shaft connections of intermediate belt pulley 66 and of drive belt pulley 62 with their respective gear wheels of gear wheel transmission stage 64 also penetrate lateral wall 30d of housing 30.

[0098] Gear wheel transmission stage 64, intermediate belt pulley 66, working belt pulley 70, and working belt 68 form a transmission gear 76, which transmits torque from drive belt pulley 62 to grooving-cutting drum 32 while reversing the direction of rotation. Drive belt pulley 62 and grooving-cutting drum 32 therefore rotate in opposite directions.

[0099] FIG. 2 shows gear wheel transmission stage 64, a front wall of transmission housing 78, which faces lateral wall 30d of housing 30 and lies directly across from it in the installed state, having been omitted in order to show the gear wheels of gear wheel transmission stage 64 in more detail.

[0100] Transmission housing 78 comprises a circumferential mounting flange 78a having a plurality of mounting bores 78b, which are penetrated by screws (not shown) in order to fasten the transmission housing 78, which completely encloses gear wheel transmission stage 64, to the inner side of lateral housing wall 30d that is facing away from the viewer of FIG. 1. The back wall 78c shown in FIG. 2 is ribbed in a manner known per se to increase its stiffness.

[0101] Belt pulley axes P62 and P66 run orthogonally with respect to the drawing plane of FIG. 2. Belt pulley shafts rotating about the respective belt pulley axes may be seen in the FIG., namely, drive belt pulley shaft 80 connected in a rotationally fixed manner to drive belt pulley 62 and intermediate belt pulley shaft 82 connected in a rotationally fixed manner to intermediate belt pulley 66.

[0102] Drive belt pulley shaft 80 penetrates a drive gear wheel 84 and is coupled with positive fit to drive gear wheel 84 via two springs 86 for joint rotation. In the same manner, intermediate belt pulley shaft 82 is connected in a rotationally fixed manner to the intermediate gear wheel 88 that it penetrates.

[0103] Drive gear wheel 84 meshes with a first mediator gear wheel 87, which in turn meshes with a second mediator gear wheel 89, which in turn meshes with intermediate gear wheel 88. Gear wheels 84, 87, 89, and 88 form a gear wheel train for transmitting torque between drive belt pulley 62 and intermediate belt pulley 66. If drive gear wheel 84 and intermediate gear wheel 88 are sufficiently large, they may also mesh directly with one another, in which case given the center distance between the belt pulley axes P62 and P66 depicted in FIG. 2 the volume enclosed by transmission housing 78 would have to be greater.

[0104] The entire gear wheel transmission stage 64 has a speed transmission ratio of between 0.9 and 1.3. Each individual meshing gear wheel pairing of gear wheel transmission stage 64 likewise has a speed transmission ratio of between 0.9 and 1.3. The concrete embodiment of the speed transmission ratio also depends on the selection of the diameters of the belt pulleys 56, 62, 66, and 70 involved in the torque transmission since the diameter ratios of belt pulleys that are coupled by a common belt also establish a transmission ratio.

[0105] As is indicated in FIG. 2 by dashed lines, intermediate belt pulley shaft 88 exits transmission housing 78 through back wall 78c and is there connected, concealed for the viewer of FIG. 2 by transmission housing 78, to a first clutch component of a switchable start-up clutch 90. A second clutch component, which selectively may be brought into a torque-transmitting connection with the first clutch component or may be separated from the latter by switching the start-up clutch 90, is connected to a start-up motor 92. Start-up motor 92 may be an electric motor or a hydraulic motor. It is preferably supplied with energy by a machine frame-side source of energy. This energy supply connection is established when interchangeable unit 28 is connected to machine frame 12 and is disconnected again when interchangeable unit 28 is released from machine frame 12.

[0106] Start-up motor 92 is able to accelerate grooving-cutting drum 32, which is coupled to intermediate belt pulley shaft 82 and to intermediate belt pulley 66 supported by it, from standstill or from a low starting speed to a first limit speed, from which point onward motor 52 of road construction machine 10 takes over the further acceleration up to the predetermined removal speed. When transferring the drive function from start-up motor 92 to main motor 52, drive belt tensioner 60 together with drive belt 58 may be used as a slip clutch by displacement and consequently by changing the tension of drive belt 58.

[0107] Likewise, when braking grooving-cutting drum 32, start-up motor 92 may be used as a resistance to rotation, for example in that grooving-cutting drum 32 drives start-up motor 92 in generator operation or drives it as a hydraulic pump in the case in which start-up motor 92 is a hydraulic motor.

[0108] FIG. 3 shows a perspective view of interchangeable unit 28. The figure shows a drum basin 94 surrounding the grooving-cutting drum 32 at a small radial distance, which is formed in the lower region of housing 30 and which comprises working opening 30c. An end strip 96 comprising an elastic lip toward ground surface A terminates working opening 30c as tightly as possible with ground surface A so that a dirt load produced by the grooving-cutting drum during ground work is as low as possible in the outer surroundings of interchangeable unit 28.

[0109] A region 30e of housing 30 situated above drum basin 94 and extending up to connecting section 30a is protected by drum basin 94 against the dirt produced and stirred up by grooving-cutting drum 32 and is therefore able to act as a cavity for accommodating for example gear wheel transmission stage 64, switchable start-up clutch 90 and start-up motor 92. A longitudinal wall 30f in region 30e, which is orthogonal with respect to working axis R, may be used for mounting start-up motor 92, for example. The front wall of transmission housing 78 may therefore be formed by lateral wall 30d of housing 30.

[0110] Working belt tensioner 72 comprises a tensioning roller 72a and a piston-cylinder assemblage 72b as actuator for displacing tensioning roller 72a, tensioning roller 72a and piston-cylinder assemblage 72b being coupled by a lever mechanism 72c.