Track vehicle, in particular a construction machine, in particular a road construction machine, having a chain tensioner and method for operating a track vehicle having a chain tensioner
阅读说明:本技术 具有链条张紧装置的履带式车辆、尤其工程机械、特别是道路工程机械以及用于运行具有链条张紧装置的履带式车辆的方法 (Track vehicle, in particular a construction machine, in particular a road construction machine, having a chain tensioner and method for operating a track vehicle having a chain tensioner ) 是由 J·福斯特 J·施塔尔 于 2019-03-27 设计创作,主要内容包括:本发明涉及一种履带式车辆、尤其工程机械、尤其道路工程机械,其具有至少一个驱动马达和用于产生驱动行驶压力的行驶驱动液压回路的被驱动马达驱动的行驶泵、至少一个履带行走机构,所述履带行走机构包括通过行驶驱动液压回路驱动的驱动轮、至少一个引导轮、环状地环绕驱动轮和引导轮的链条以及用于张紧链条的链条张紧装置,并且链条张紧装置包括具有链条张紧液压缸的调节装置,通过链条张紧液压缸能调整在履带行走机构的两个车轮(尤其驱动轮和引导轮)之间的间距以张紧链条,链条张紧液压缸通过液压张紧管路连接到液压的预紧源上,其能通过液压的预紧源以初始预紧压力加载。张紧装置还具有带有弹簧的缓冲装置,用于缓冲在调节装置中的压力峰值。本发明也涉及一种用于运行具有履带行走机构的履带式车辆的方法。(The invention relates to a crawler vehicle, in particular a construction machine, in particular a road construction machine, having at least one drive motor and a travel pump driven by the drive motor for generating a travel drive hydraulic circuit for driving a travel pressure, having at least one crawler track, the crawler traveling mechanism comprises a driving wheel driven by a traveling driving hydraulic circuit, at least one guide wheel, a chain annularly surrounding the driving wheel and the guide wheel, and a chain tensioning device for tensioning the chain, the chain tensioning device also comprises an adjusting device having a chain tensioning hydraulic cylinder, by means of which the distance between the two wheels of the crawler track (in particular the drive wheel and the idler wheel) can be adjusted in order to tension the chain, and which is connected via a hydraulic tensioning line to a hydraulic pretensioning source, which can be acted on by the hydraulic pretensioning source with an initial pretensioning pressure. The tensioning device also has a damping device with a spring for damping pressure peaks in the adjusting device. The invention also relates to a method for operating a tracked vehicle having a crawler track.)
1. A tracked vehicle (1) having:
-at least one drive motor (3) and a travel pump (9) driven by the drive motor (3) for generating a travel drive hydraulic circuit (10) for driving a travel pressure,
-at least one crawler track (4), wherein the crawler track (4) comprises: a drive wheel (12) driven by the travel drive hydraulic circuit (10), at least one guide wheel (14), a chain (13) looped around the drive wheel (12) and the guide wheel (14), and a chain tensioning device (15) for tensioning the chain (13);
Wherein the chain tensioning device (15) comprises an adjusting device (16) having a chain tensioning hydraulic cylinder (17), by means of which the distance between the two wheels (12, 14) of the crawler track can be adjusted in order to tension the chain (13), wherein the chain tensioning hydraulic cylinder (17) is connected via a hydraulic tensioning line (18) to a hydraulic pretensioning source (19), by means of which it can be acted upon with an initial pretensioning pressure,
and the chain tensioner (15) further has a damping device (21) with a spring (23, 23') for damping pressure peaks in the adjusting device (16),
it is characterized in that the preparation method is characterized in that,
the damping device (21) has an additional tensioning device (22) which is designed in such a way that it changes the initial pretensioning pressure independently of the pretensioning source (19) as a function of the drive travel pressure in the travel drive hydraulic circuit (10) toward the pretensioning pressure in the chain tensioning hydraulic cylinder (17) which is associated with the change in the drive travel pressure, and the additional tensioning device (22) comprises an additional tensioning hydraulic cylinder (25), the additional tensioning hydraulic cylinder has a hydraulic cylinder (24) and a cylinder piston (26) which is adjustably mounted in the hydraulic cylinder, the cylinder piston divides the inner space of the additional tensioning hydraulic cylinder (25) into a piston space and a piston rod space, wherein the additional tensioning hydraulic cylinder (25) is acted upon by a spring (23, 23') of the damping device (21), in particular on the piston rod side, with an adjusting force.
2. The tracked vehicle (1) according to claim 1, characterized in that the additional tensioning device (22) is configured such that it increases the actual pretensioning pressure in the chain tensioning hydraulic cylinder (17) relative to the initial pretensioning pressure when driving backwards.
3. The tracked vehicle (1) according to any one of the preceding claims, characterised in that the additional tensioning device (22) is constructed in the form of a hydraulic conversion unit, in particular so that it converts pressure changes in the drive running pressure into smaller pressure changes in the chain tensioning hydraulic cylinder (17).
4. The tracked vehicle (1) according to any one of the preceding claims, characterised in that the additional tensioning hydraulic cylinder (25) has, in addition to the piston rod space, a pressure spring space which is separate from the piston rod space, into which pressure spring space the cylinder piston projects at the end side and in which pressure spring space the pressure spring of the damping device is arranged completely.
5. The tracked vehicle (1) according to any one of the preceding claims, wherein the additional tensioning device (22) is connected in a fluid-tight manner to the hydraulic tensioning tube or directly to the chain tensioning hydraulic cylinder (17) by means of an additional tensioning connection line (27).
6. The tracked vehicle (1) according to any one of the preceding claims, characterised in that there is a travel drive connection line (28) from the travel drive hydraulic circuit (10), in particular from the high-pressure side thereof during backward travel, to the additional tensioning hydraulic cylinder (25), by means of which the additional tensioning hydraulic cylinder (25) is in fluid-conducting connection with the travel drive circuit (10).
7. The tracked vehicle (1) according to claims 5 and 6, characterized in that the additional tensioning connection line (27) and the travel drive connection line (28) are arranged such that the additional tensioning connection line (27) is in fluid connection with the piston space and the travel drive connection line (28) is in fluid connection with the piston rod space of the additional tensioning hydraulic cylinder (25).
8. The tracked vehicle (1) according to any one of the preceding claims, characterised in that the damping device (21) is arranged outside the crawler track.
9. The tracked vehicle (1) according to any one of the preceding claims, characterised in that the damping device (21) is centrally connected simultaneously with two or more chain-tensioning hydraulic cylinders (17) of two or more crawler tracks (4).
10. The tracked vehicle (1) according to any one of the preceding claims, characterized in that it is a working machine, in particular a road working machine.
11. Method for operating a tracked vehicle (1), in particular a tracked vehicle (1) according to claims 1 to 10, with a chain tensioner (15), in particular a chain tensioner of a tracked vehicle (1) according to the preceding claim, comprising the steps of:
a) pretensioning (29) a chain of the crawler chassis around the drive wheel (12) and the idler wheel (14) with an initial pretensioning pressure by means of a chain tensioning hydraulic cylinder connected to a hydraulic pretensioning source;
b) damping (30) pressure peaks occurring in the chain tensioning hydraulic cylinder by means of a pressure spring of a damping device;
c) the initial pretensioning pressure is changed (31) by means of an additional tensioning device acting as a function of the drive travel pressure in the travel drive hydraulic circuit, toward the pretensioning pressure in the chain tensioning hydraulic cylinder, which is associated with the change in the drive travel pressure.
12. Method according to claim 11, characterized in that in step c) the cylinder piston of an additional tensioning hydraulic cylinder is loaded with hydraulic fluid on the input side via a travel drive connection line, which is fluidly connected to a travel drive hydraulic circuit, and which is fluidly connected to the chain tensioning hydraulic cylinder on the output side.
13. Method according to any of claims 11 or 12, characterized in that in step c) the hydraulic pressure is converted by the additional tensioning device, in particular in such a way that the pressure in the travel drive circuit is changed to the chain tensioning hydraulic cylinder becoming smaller.
Technical Field
The invention relates to a tracked vehicle (in particular a construction machine, in particular a road construction machine) having a chain tensioner, and to a method for operating a tracked vehicle (in particular a construction machine) having a chain tensioner.
Background
A prior type of tracked vehicle is a tracked vehicle having a crawler track. The main elements of a crawler are a chain (also commonly referred to as a track) and at least two wheels surrounded by the chain, of which one is driven (drive wheel) and at least one guide (idler wheel) essentially for the chain, and optionally pulleys. In practical use, it is important that the chain is tensioned in a defined tensioning region in order to prevent, on the one hand, the dropping off of the chain and, on the other hand, to keep the wear on the chain as low as possible. For this purpose, so-called chain tensioners are generally used. Chain tensioners of this type with a track running gear for tracked vehicles, in particular for construction machines, are known from the prior art. A prior type of chain tensioner is a walking chain tensioner. Such track-type vehicles (and in particular also construction machines, in particular road construction machines) usually comprise at least one drive motor (usually an internal combustion engine) and a drive pump driven by the drive motor for generating a drive hydraulic circuit for driving the drive pressure. The driving running pressure is used for running the driving crawler (in particular, driving the driving wheel). For this purpose, the drive wheels are typically driven by a travel drive hydraulic circuit. For tensioning, the chain tensioning device comprises in particular an adjusting device with a chain tensioning hydraulic cylinder, by means of which the distance between at least two wheels of the crawler track, in particular between the drive wheel and the idler wheel and/or the distance between the first and second idler wheels, can be adjusted, typically in the horizontal direction, in order to tension the chain, wherein the chain tensioning hydraulic cylinder is connected to a hydraulic pretensioning source by means of a hydraulic tensioning line, by means of which the chain tensioning hydraulic cylinder can be loaded with an initial pretensioning pressure. The chain is thus tensioned to an initial value by the pretensioning source, for example in particular by generating the desired hydraulic pressure in the chain tensioning cylinder. Of course, starting from such a pretensioning or such a pretensioning pressure, a change in the pressure acting in the chain tensioning cylinder during operation may occur, either due to wear or due to a change in the direction of rotation of the chain (for example when changing from forward to backward travel), in the case of a foreign body penetrating between the drive or guide wheel and the chain, for example due to stones or the like, or due to a polygonal action of the individual links of the chain during travel operation. Such pressure peaks are undesirable, since they can lead to unreliable operating conditions and significantly increase wear phenomena. In order to avoid or to dampen pressure peaks that may occur in the chain tensioning hydraulic cylinder, it is known to provide the chain tensioning device with a damping device having a spring (in particular a compression spring or a tension spring) for damping pressure peaks in the adjusting device. Such a spring may for example be functionally arranged between the chain tensioning hydraulic cylinder and the guide pulley, as is for example disclosed in DE 102009013708 a 1. However, it is problematic in such an arrangement that the tensioning force fluctuates with a change in the compression position of the spring of the damping device and increases in particular with an increasing compression position of the spring. However, it is desirable to configure the chain tensioner in such a way that the pressure in the adjusting cylinder is as constant as possible over almost the entire spring travel of the spring of the damping device.
A further challenge in the operation of the crawler track described above is that the pressure level required to maintain sufficient chain tension changes during the change of direction of travel. The guide wheel can, for example, be arranged in front of the drive wheel in the forward direction, so that in this case the chain is supported on the drive wheel, which receives the force resulting from the propulsion torque. When the direction of travel is reversed, the situation changes in such a way that the support of the chain on the guide wheel is now taking place, which often triggers a strong compression of the damping device. Thereby, the risk of the chain undesirably falling off when traveling backward rises. In this case, for example, US 6224172B 1 has proposed a chain tensioner with pressure control in relation to the direction of travel. For this purpose, sensors are provided which determine the pressure conditions in the hydraulic circuit of the driving system. The control unit then adapts the pressure in the control cylinder in such a way that it is greater or smaller in relation to the respectively opposite direction of travel. This solution is relatively complex and costly, since, for example, an electric control and an additional hydraulic valve are required. Furthermore, so-called Delta-Laufwerke is also known, in which the drive wheels are located vertically above the two guide wheels and horizontally between the two guide wheels. For such crawler track units, it is also known to attach a chain tensioner to one of the idler wheels.
Disclosure of Invention
The object of the present invention is therefore to provide a crawler vehicle (in particular a construction machine having at least one crawler track) of the type mentioned above and a method for operating a crawler vehicle (in particular a construction machine) which eliminate the above-mentioned problems, in particular to provide a possibility for a chain tensioner in which, on the one hand, the tensioning pressure in the chain tensioning cylinder can be optimally controlled, in particular adjusted, depending on the current direction of travel and, on the other hand, the tensioning pressure prevailing in the chain tensioning cylinder is simultaneously influenced by the different compression positions of the pressure spring of the damping device in as small an amount as possible. Basically, for this purpose, the "tensioning" and "damping" functions are decoupled from one another.
The object is achieved by a track vehicle, in particular a construction machine, in particular a road construction machine, and a method for operating a track vehicle, in particular according to the invention, according to the independent claims. Preferred embodiments are specified in the dependent claims.
One type of tracked vehicle of the above-mentioned type comprises at least one drive motor, typically an internal combustion engine or an electric motor. The drive motor is used to drive a travel pump of a travel drive hydraulic circuit, by means of which a drive travel pressure is generated, for example in order to operate a hydraulic motor that drives the drive wheels. The tracked vehicle further comprises at least one and in particular a plurality of crawler tracks. The main elements of the at least one crawler track are a drive wheel which is driven by a travel drive hydraulic circuit (wherein the drive is in particular effected, for example, by a hydraulic motor), at least one idler wheel, a chain (for example a crawler belt) which surrounds the drive wheel and the idler wheel in an endless manner, and a chain tensioning device for tensioning the chain. In contrast to the drive wheel, the at least one guide wheel is therefore not driven directly, but rather passively, and therefore essentially performs the guide function for the revolving chain. In addition, the crawler can have one or more pulleys. The main task of the chain tensioner is to configure a tensioning of the circulating chain that is sufficient, in particular, for driving operation. For this purpose, the chain tensioner comprises an adjusting device having a chain tensioning hydraulic cylinder, by means of which the distance between two wheels of the crawler track, in particular between the drive wheel and the at least one idler wheel, can be adjusted for tensioning the chain. For this purpose, the chain tensioning hydraulic cylinder is connected via a hydraulic tensioning line to a hydraulic pretensioning source, via which the chain tensioning hydraulic cylinder can be acted upon with an initial pretensioning pressure. The task of the hydraulic tensioning line is therefore essentially to achieve a supply of fluid to the chain tensioning hydraulic cylinder in order to build up a pretension (by a pushing-away movement of the guide wheel and the drive wheel from each other). As will be shown below, this line can also be used for damping purposes. For this purpose, the hydraulic tensioning line is supplied with hydraulic fluid by a hydraulic preloading source, for example, comprising a pump and at least one valve (in particular a switchable non-return valve). In particular, it can be provided, in particular, that the hydraulic pretensioning source builds up the desired pretensioning force at the chain tensioning cylinder as the drive motor is started when the machine is at a standstill and, when the desired pretensioning force is reached, the fluid connection between the chain tensioning cylinder and the hydraulic pretensioning source is blocked or interrupted by a valve. In addition to such a mechanism for establishing the desired chain tension when starting the machine, the tensioning device comprises a damping device with a spring (in particular a tension spring or a compression spring) for damping pressure peaks in the adjusting device. Such pressure peaks can occur, for example, when driving over an edge or can be caused by foreign bodies (e.g., stones) located between the chain and the drive wheel or the at least one guide wheel or, however, also by pressure fluctuations due to the polygonal action of the drive chain.
In order to solve this object, it is provided according to the invention that the damping device has an additional tensioning device which is designed in such a way that it changes the initial pretensioning pressure independently of the pretensioning source as a function of the driving travel pressure in the travel drive hydraulic circuit towards the pretensioning pressure in the chain tensioning hydraulic cylinder which is dependent on the change in the driving travel pressure. The damping device thus comprises a device by means of which the influencing and changing of the pressure loading of the chain tensioning cylinder by means of the hydraulic line can be effected independently of the above-mentioned pretensioning device. The control and regulation of the pressure application during the driving operation of the work machine is therefore not performed by the pretensioning source, but by an additional tensioning device which ideally acts hydraulically. In this case, the adaptation by means of the additional tensioning source takes place as a function of the driving pressure in the driving hydraulic circuit. If there is a pressure rise, this, according to the invention, leads to a rise in the pretensioning pressure in the chain tensioning cylinder by means of the additional tensioning device, which rise is effected by the additional tensioning device acting separately from the pretensioning source. This brings the advantages at the same time: the control of the pretension source during driving operation can be dispensed with.
The additional tensioning device is preferably designed such that, when driving backwards, it increases the actual pretensioning pressure in the chain tensioning cylinder relative to the initial pretensioning pressure, relative to the forward driving. The actual pretensioning pressure is the pressure of the hydraulic fluid acting on the chain tensioning hydraulic cylinder during driving operation, which can be varied depending on the situation from the initial pretensioning pressure generated by the hydraulic pretensioning source prior to driving operation, as already explained above. When the driving wheel is arranged behind the guide wheel, seen in the forward direction of the working machine, an increase in the actual pretensioning pressure during backward travel is advantageous in order to improve the support properties of the guide wheel.
The pressure changes occurring in the driving hydraulic circuit usually do not correspond to the chain tension changes for an optimized chain tension in different operating states or driving directions. For this reason, it has proven to be preferred if the additional tensioning device is designed in the form of a hydraulic switching unit, in particular such that it switches the pressure change in the drive travel pressure into a smaller pressure change in the chain tensioning hydraulic cylinder. This enables as good a coordination as possible: the pressure in the travel drive hydraulic circuit varies to the extent that it is acted upon by an additional tensioning device in the chain tensioning hydraulic cylinder. The main variables which play a role in the determination of the optimized conversion ratio can be the supply pressure, the maximum driving pressure, the hydraulic volume per switching fluid of the respective hydraulic motor, the transmission ratio, the hydro-mechanical efficiency of the transmission and the hydraulic motor, the sprocket diameter, the diameter of the chain tensioning cylinder and/or the pretensioning force of the springs used.
In a particularly preferred embodiment, the additional tensioning device comprises an additional tensioning hydraulic cylinder having a cylinder and a cylinder piston which is mounted therein in an adjustable manner and which divides the interior of the additional tensioning hydraulic cylinder into a piston space and a piston rod space, wherein the additional tensioning hydraulic cylinder is acted upon with an adjusting force by a spring of the damping device, in particular on the piston rod side. In general, therefore, spring tensioning cylinders are used for the construction of the additional tensioning device. The spring-loaded, in particular pressure-spring-loaded, cylinder piston can be adjusted in a floating or lock-free manner between two stop end positions inside the cylinder.
Preferably, the additional tensioning hydraulic cylinder has, in addition to the piston rod space, a spring space which is separate from the piston rod space and into which the cylinder piston projects at the end face and in which the spring (in particular the pressure spring) of the damping device is arranged completely. The spring space can in particular be a space which is ventilated with respect to the outside environment. Alternatively, it is also possible for the spring to be arranged completely in the cylinder piston space, in particular on the low-pressure side.
In order to achieve a most direct possible attachment of the additional tensioning device to the chain tensioning hydraulic cylinder, the additional tensioning device is preferably connected in a fluid-tight manner to the hydraulic tensioning line via an additional tensioning connection line or directly to the chain tensioning hydraulic cylinder. Thus, if a connection to the hydraulic tensioning line is made, it is also used for fluid guidance in the event of damping. This can be advantageous in that there is usually only very limited installation space available around the chain tensioning hydraulic cylinder.
In a particularly simple and efficient embodiment, a travel drive connection line is provided from the travel drive hydraulic circuit, in particular from the high-pressure side of the travel drive hydraulic circuit during backward travel, to the additional tensioning hydraulic cylinder, via which the additional tensioning hydraulic cylinder is connected in a flow-conducting manner to the travel drive circuit. In this case, it is particularly preferred that the attachment of the additional tensioning hydraulic cylinder to the travel drive hydraulic circuit is effected only via the single travel drive connecting line on the high-pressure side of the travel drive hydraulic circuit during backward travel. The travel drive hydraulic circuit as described thus relates to a hydraulic circuit between the travel pump and the travel drive (e.g. a hydraulic motor for driving the drive wheels). This includes not only embodiments in which the hydraulic circuit comprises only a single travel pump and a single travel drive, but also variants in which the hydraulic circuit comprises a single travel pump and a plurality of travel drives. The main feature is, in particular, the use of an additional tensioning hydraulic cylinder for each pump circuit. Depending on which direction of rotation the hydraulic motor is operated or in which direction the travel pump is delivering, a higher pressure level exists on one side of the hydraulic circuit between the travel pump and the hydraulic motor than on the opposite side. The side with the correspondingly higher pressure level corresponds to the current high-pressure side. Since the chain of the crawler track is usually supported by the idler wheel during backward travel of the work machine, it is preferable if the additional tensioning device according to the invention engages and selectively increases the pretensioning in the chain tensioning cylinder for backward travel, precisely in this operating situation. This travel direction dependency also reflects the main use case according to the invention of the additional tensioning device. It is therefore also sufficient for the attachment of the additional tensioning device to the travel drive hydraulic circuit to take place only via this one travel drive connection.
Preferably, the additional tensioning connection line and the travel drive connection line are arranged in such a way that the additional tensioning connection line is fluidically connected to the piston space and the travel drive connection line is fluidically connected to the piston rod space of the additional tensioning hydraulic cylinder. The additional tensioning hydraulic cylinder thus converts the pressure changes occurring in the travel drive hydraulic circuit into smaller pressure changes at the chain tensioning hydraulic cylinder. In this way, it is avoided that a relatively high driving pressure (for example in the range of 425 bar) acts on the chain tensioning cylinder in this order of magnitude, which can be disadvantageous, in particular, with regard to chain wear and the layout of the chain tensioning cylinder to be used.
One essential advantage of the invention is that the damping device according to the invention can be arranged separately from the crawler track and therefore in particular outside the crawler track, since the attachment of the damping device, including the additional tensioning device, to the chain tensioning cylinder takes place jointly and exclusively via a hydraulic line, in particular an additional tensioning connecting line. This not only achieves a particularly space-saving overall arrangement, but additionally exhibits the possibility of: the damping device, including the additional tensioning device, is arranged outside a dirty region of the working machine, for example inside the machine. This reduces susceptibility to wear and eases maintenance work. Preferably, the arrangement of the additional tensioning device or its damping device on the machine frame takes place.
In principle, it is possible to equip several or each of the crawler tracks of the construction machine with its own damping device according to the invention. However, the present invention now exhibits the advantages of both: the damping device can be connected centrally at the same time to two or more crawler tracks of a crawler vehicle, in particular a construction machine, in particular to two or more adjusting cylinders of all crawler tracks. For this purpose, the additional tensioning hydraulic cylinder can be in fluid connection with a plurality of chain tensioning hydraulic cylinders simultaneously, for example, via an additional tensioning connection line and a branch. Thus, one central damping device of all connected crawler tracks is possible and at the same time a travel direction-dependent pressure increase in all connected chain-tensioning hydraulic cylinders is possible.
The present invention generally relates to tracked vehicles. Preferably, according to the invention, the tracked vehicle relates to a working machine, in particular to a road working machine. The invention is also particularly suitable for use in road-cooled grinding mills
A road finisher or feeder.A further aspect of the invention consists in a method for operating a tracked vehicle, in particular according to the preceding claims. The main step of the method according to the invention is to pretension the chain of the crawler track running gear around the drive wheel and the idler wheel with an initial pretensioning pressure by means of a chain tensioning hydraulic cylinder connected to a hydraulic pretensioning source. In this step, the chain tensioning hydraulic cylinder is therefore initially loaded with a tensioning pressure. This is done, for example, when the drive motor of the tracked vehicle is activated. The hydraulic pretensioning source used for this purpose is used only for this pretensioning and has no influence on the change in the pretensioning pressure on the chain tensioning cylinder during driving operation. Thus, if the desired pretensioning pressure has already been established by the pretensioning source, it can also be provided that the fluid connection is then interrupted by a valve or the like toward the pretensioning source. The pretensioning pressure prevailing in the chain pretensioning cylinder is then also referred to herein as the initial pretensioning pressure. In addition, during the driving operation of the tracked vehicle, pressure peaks occurring in the chain tensioning hydraulic cylinder are damped by means of the springs (in particular compression springs or tension springs) of the damping device. Here, such pressure peaks can be at least partially compensated for, for example, by the compression of the spring. Furthermore, according to the invention, the method according to the invention simultaneously comprises changing the initial pretensioning pressure by means of an additional tensioning device acting as a function of the driving travel pressure in the travel drive hydraulic circuit towards a pretensioning pressure in the chain tensioning hydraulic cylinder which is dependent on the change in the driving travel pressure in the travel drive hydraulic circuit. The additional tensioning device therefore has the task of: the pressure of the hydraulic fluid acting on the chain tensioning hydraulic cylinder is varied independently of the pretensioning device, specifically depending on the direction of travel of the tracked vehicle. The increase in the fluid pressure in the chain tensioning cylinders, for example when the tracked vehicle is traveling backwards, is therefore not effected by the hydraulic pretensioning source, but only by the additional tensioning device. For this purpose, for example, existing valves for establishing a fluid connection to a hydraulic preloading source are kept closed. In the method according to the invention, it is therefore not necessary to use a hydraulic pretensioning source for adapting the pretensioning during driving operation.
Preferably, with the method according to the invention, it is provided that, when the initial tensioning pressure is changed by means of the additional tensioning device, the input side of the cylinder piston of the additional tensioning hydraulic cylinder is acted upon with hydraulic fluid via a travel drive connection line which is fluidically connected to the travel drive hydraulic circuit and the additional tensioning hydraulic cylinder is fluidically connected on the output side to the chain tensioning hydraulic cylinder. In addition or alternatively, the hydraulic pressure can also be converted by an additional tensioning device, in particular in such a way that the pressure in the travel drive circuit is changed to a smaller chain tensioning hydraulic cylinder. For details, reference is additionally made to embodiments relating to the tracked vehicle according to the invention.
Drawings
The invention will be described in more detail below on the basis of embodiments illustrated in the drawings. The figures are schematic:
fig. 1 shows a side view of a track-laying vehicle of the construction machine type, in particular a road grinding mill;
FIG. 2 shows a view of a crawler track;
FIG. 3 shows a detail from a hydraulic circuit diagram;
FIG. 4 shows a comparison of the dependence of chain tension on spring travel according to an embodiment of the present invention with a graph of a known solution from the prior art;
FIG. 5 shows a flow chart of a method according to the invention;
FIG. 6 shows a side view of a work machine of the road finisher type;
figure 7 shows a side view of a work machine of the feeder type;
FIG. 8 shows a portion of a hydraulic circuit diagram from an alternative embodiment;
9A-9D illustrate an alternative embodiment of a spring tensioning cylinder;
FIG. 10 shows a view of a triangular undercarriage type crawler track;
fig. 11 shows the profile of the drive travel pressure and the pretensioning pressure in the chain tensioning hydraulic cylinder adapted thereto; and
fig. 12A-12E illustrate additional preferred versions of the tracked vehicle.
Functionally and/or structurally identical components are denoted by the same reference numerals in the figures, wherein repeated components in the figures are not necessarily denoted in each figure.
Detailed Description
Fig. 1 first illustrates a
Fig. 2 diagrammatically shows one of the crawler tracks 4 of fig. 1 and the drive of the crawler track. The
Furthermore, the chain tensioner comprises a damping
Such an embodiment of the damping
It is now essential that the additional tensioning hydraulic cylinder is at the same time in a flow-conducting connection via the travel
A particularly great advantage of the arrangement described above is now that the transmission of pressure changes from the travel drive hydraulic circuit has virtually no effect on the damping characteristic achieved by the
A further major advantage of the arrangement described is that a central damping
In the case of a plurality of simultaneous chain-tensioning hydraulic cylinders, the attachment of the damping
Fig. 5 diagrammatically shows a method according to the invention for operating a working machine as described above in the form of a flow chart. In
Fig. 6 and 7 schematically depict exemplary further working machines, in particular road working machines, for which a damping device of the type explained above is particularly suitable, wherein reference is made to the previous embodiment for details of the damping device. Fig. 6 shows a road finisher and fig. 7 shows a feeder.
Fig. 8 shows a partial alternative example of the hydraulic circuit diagram according to fig. 3, wherein, with regard to construction and operating principle, reference is made essentially to the previous embodiment, in particular to the embodiment of fig. 3. The main difference here is that the travel
Fig. 9A to 9D diagrammatically show alternative configurations of the spring tensioning cylinder of the
Fig. 10 shows an embodiment according to the invention of a so-called tripod. Essentially, reference is made herein to the above embodiment in fig. 2. The difference is now that the
The diagram from fig. 11 shows the profile of the change in the driving hydraulic pressure in the driving
Fig. 12A to 12E finally show a further tracked vehicle which is particularly suitable for the use of the damping
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