CN219317286U

CN219317286U - Hydraulic system for automatically adjusting tension of crawler belt and working machine

Info

Publication number: CN219317286U
Application number: CN202223308607.5U
Authority: CN
Inventors: 舒全禄; 杨洪波; 张为荣
Original assignee: Sany Heavy Machinery Chongqing Co ltd
Current assignee: Sany Heavy Machinery Chongqing Co ltd
Priority date: 2022-12-09
Filing date: 2022-12-09
Publication date: 2023-07-07
Anticipated expiration: 2032-12-09

Abstract

The utility model discloses a hydraulic system and a working machine for automatically adjusting the tension of a crawler belt. The hydraulic system includes: the telescopic device is used for adjusting the tension of the crawler belt; the first oil supply branch is connected with the telescopic device and is used for providing hydraulic oil with a first pressure value; the second oil supply branch is connected with the first oil supply branch in parallel and connected with the telescopic device, and is used for providing hydraulic oil with a second pressure value, and the second oil supply branch can be cyclically opened and closed according to a preset period, and the second pressure value is larger than the first pressure value; the energy storage oil way is connected with the telescopic device and is used for balancing the pressure change of the telescopic device within a preset pressure value range; the first safety oil way can be used for relieving pressure of the system when the second oil supply branch is opened, and is in a closed state when the second oil supply branch is closed. The hydraulic system and the working machine provided with the system can adapt to various complex working conditions, and can automatically calibrate the system pressure to realize automatic protection.

Description

Hydraulic system for automatically adjusting tension of crawler belt and working machine

Technical Field

The utility model relates to the technical field of engineering machinery, in particular to a hydraulic system for automatically adjusting the tension of a crawler belt and a working machine provided with the hydraulic system.

Background

Heavy machinery, such as an excavator, a crawler crane, a rotary drilling machine/pile machine and the like, commonly adopts a crawler travelling device, has the advantages of large traction force, low ground ratio, strong climbing capacity, small turning radius and the like, and is widely applied to the field of engineering machinery.

In the actual working process, the tension of the crawler belt greatly affects the walking performance of the crawler belt:

if the tension is too large, the rigidity of the crawler belt is too large, the tension device cannot play a role in buffering, and meanwhile, the internal friction of the crawler belt running machine is increased, so that the transmission efficiency is low and the crawler belt is excessively worn;

too small tension force can cause the loose track to play a role in tensioning, and meanwhile, the vibration and the jump of the track are caused, so that friction force is increased, and abrasion is increased.

If the crawler running device encounters obstruction during running, the tensioning degree of the crawler needs to be quickly adjusted so as to adapt to working conditions and overcome obstruction, and meanwhile, the requirement of running of the whole crawler running device is met.

In a hydraulic system for adjusting the tension of a track, a spring tensioning mode or a hydraulic tensioning mode of maintaining pressure of a hydraulic accumulator is mostly adopted. When the sudden change and heavy load working conditions are met, the problems of limited tensioning force and poor adaptability exist in a spring tensioning mode, and the problem of rising of a system danger coefficient caused by long-time high pressure exists in a hydraulic tensioning mode of pressure maintaining of the energy accumulator. The tensioning force is required to be manually and frequently adjusted in the using process of the two tensioning modes, so that the tensioning force is difficult to adapt to complex working conditions, and the component loss is high and the using effect is poor under heavy-load working conditions.

Disclosure of Invention

Accordingly, the present utility model is directed to a hydraulic system for automatically adjusting the tension of a track (simply referred to as a hydraulic system), and a working machine provided with the hydraulic system, which can adapt to various complex working conditions, has good overall durability, and can automatically calibrate the system pressure, thereby achieving an automatic protection effect and preventing accidents.

In order to achieve the above purpose, the present utility model provides the following technical solutions:

a hydraulic system for automatically adjusting track tension, comprising:

the telescopic device is used for adjusting the tension of the crawler belt;

the first oil supply branch is connected with the telescopic device and is used for providing hydraulic oil with a first pressure value P1;

the second oil supply branch is connected with the first oil supply branch in parallel and is connected with the telescopic device, the second oil supply branch is used for providing hydraulic oil with a second pressure value P3, the second oil supply branch can be opened and closed circularly according to a preset period, and the second pressure value P3 is larger than the first pressure value P2;

the energy storage oil way is connected with the telescopic device and is used for balancing the pressure change of the telescopic device within a preset pressure value range;

the first safety oil way can be used for releasing pressure for the system when the second oil supply branch is opened, and is in a closed state when the second oil supply branch is closed.

Optionally, in the above hydraulic system, a first relief valve is provided in the first oil supply branch, and a set pressure of the first relief valve is the first pressure value P2;

and/or a second pressure reducing valve and a first switching valve are arranged in the second oil supply branch, the set pressure of the second pressure reducing valve is the second pressure value P3, and the first switching valve is used for controlling the second oil supply branch to be cyclically opened and closed according to a preset period.

Optionally, in the above hydraulic system, a first relief valve and a second switching valve are disposed in the first relief oil path in series, the second switching valve is a normally closed valve, a set opening pressure of the second switching valve is the second pressure value P3, a set relief pressure of the first relief valve is a calibration pressure value P3', and the calibration pressure value P3' is greater than the first pressure value P2.

Optionally, in the above hydraulic system, the second switching valve is a two-position two-way switching valve, and a control oil path of the second switching valve is connected to the second oil supply branch, or is connected to an outlet oil path common to the second oil supply branch and the first oil supply branch.

Optionally, in the above hydraulic system, the first switching valve is an electromagnetic directional valve.

Optionally, in the above hydraulic system, an outlet of the first relief valve in the first oil supply branch is connected to a first check valve;

and/or, in the second oil supply branch, an outlet of the second pressure reducing valve is connected with a second one-way valve.

Optionally, in the above hydraulic system, a third switching valve is further included;

the third switching valve is disposed between the common inlet of the first oil supply branch and the second oil supply branch and the oil pump.

Optionally, in the above hydraulic system, further comprising:

the first energy accumulator is arranged on an oil inlet pipeline between the third switch valve and the oil pump;

and/or the second overflow valve is arranged on the oil inlet pipeline between the third switch valve and the oil pump, the set overflow pressure of the second overflow valve is a third pressure value P0, and the third pressure value P0 is larger than the second pressure value P3.

Optionally, in the hydraulic system, a second safety oil path is further included;

the second safety oil way is connected with the first safety oil way in parallel;

the set overflow pressure of the second safety oil path is larger than the set overflow pressure of the first safety oil path.

A working machine comprising a crawler running gear in which the hydraulic system for automatically adjusting the crawler tension described above is provided.

According to the technical scheme, in the hydraulic system and the working machine for automatically adjusting the tension of the crawler belt, the hydraulic energy storage mode is adopted to automatically adjust the tension of the crawler belt according to working conditions, so that the hydraulic system and the working machine are suitable for various complex working conditions, and the overall durability is good; moreover, the system pressure can be automatically calibrated regularly through the first safety oil way and the second oil supply branch way, so that the hydraulic system for adjusting the tension of the crawler belt has an automatic protection function and accidents are prevented.

Drawings

In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the utility model, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a hydraulic system diagram of a hydraulic system for automatically adjusting track tension provided by an embodiment of the present utility model.

Detailed Description

The utility model discloses a hydraulic system (hydraulic system for short) for automatically adjusting the tension of a crawler belt, and a working machine provided with the hydraulic system, which can adapt to various complex working conditions, has good integral durability, can automatically calibrate the pressure of the system, has the effect of automatic protection, and prevents accidents.

The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

Referring to fig. 1, a hydraulic system for automatically adjusting a track tension according to an embodiment of the present utility model includes a telescopic device 17, a first oil supply branch 101, a second oil supply branch 102, an energy storage oil path 105, and a first safety oil path 103. Wherein:

the telescopic device 17 is used for adjusting the tension of the crawler belt;

the first oil supply branch 101 is connected to the telescopic device 17, the first oil supply branch 101 being able to supply hydraulic oil with a first pressure value P2;

the second oil supply branch 102 and the first oil supply branch 101 are connected in parallel to form an oil supply path and are connected with the telescopic device 17; the second oil supply branch 102 can supply hydraulic oil having a second pressure value P3, and can be cyclically opened and closed according to a preset cycle, the second pressure value P3 being greater than the first pressure value P2;

the energy storage oil way 105 is connected with the telescopic device 17, and the energy storage oil way 105 can balance the pressure change of the telescopic device 17 within a preset pressure value range; specifically, the energy storage oil path 105 is connected between the oil supply path and the expansion device 17, and is configured to store energy of hydraulic oil within a preset pressure value range, and to be capable of delivering the stored energy to the expansion device 17;

the first safety oil path 103 can be used for releasing pressure for the system when the second oil supply branch 102 is opened, and is in a closed state when the second oil supply branch 102 is closed.

The "the second oil supply branch 102 is opened and closed according to a preset cycle" means that the second oil supply branch 102 can be automatically opened and closed, and the opening and closing actions automatically circulate according to a preset time cycle, and if the time cycle of the second oil supply branch 102 in the opened state is t1 and the time cycle of the second oil supply branch 102 in the closed state is t2, the opening and closing conditions of the second oil supply branch 102 are as follows:

(1) opening the second oil supply branch 102 until the duration of the second oil supply branch 102 kept in the open state reaches t1, and closing the second oil supply branch 102;

(2) returning to the previous step (1) when the duration of keeping the second oil supply branch 102 in the closed state reaches t 2;

the opening and closing operations are reciprocally circulated.

As can be seen, in this hydraulic system:

the first oil supply branch 101 has the function of normally opening and supplementing oil and pressure, and can continuously provide low-pressure oil for a subsequent oil way, namely the oil pressure of an outlet of the first oil supply branch 101 is a first pressure value P2;

the second oil supply branch 102 is turned on and off regularly, and has the function of regularly supplementing oil and pressure, and high-pressure oil can be intermittently provided for a subsequent oil way through the second oil supply branch 102, namely, the oil pressure of an outlet of the second oil supply branch 102 is a second pressure value P3;

the oil pressure change of the telescopic device 17 can be balanced in a preset pressure value range (for example, P1-P6, P1 is more than P2 is less than P3 is less than P6) through the energy storage oil way 105, so that energy storage and buffering are realized, the automatic adjustment of the tension of the crawler belt is realized, and the crawler belt can adapt to various different working conditions;

moreover, the pressure of the system can be regularly relieved through the first safety oil way 103, so that the system is prevented from being in a state of too high pressure for a long time, the problems of high component loss and poor using effect under a heavy load working condition are avoided, and the purpose of system protection is achieved. At this time, although the first relief oil passage 103 is regularly a system relief, the first relief oil passage 103 can be turned on only when the second oil supply branch passage 102 is opened, and the output oil pressure P3 of the second oil supply branch passage 102 is larger than the output oil pressure P2 of the first oil supply branch passage 101, so that even the relief can keep the system within the normal oil pressure range without affecting the normal function of the system. Therefore, the pressure relief process of the first relief oil passage 103 is referred to herein as a process of adjusting the pressure for the system.

In summary, the hydraulic system for automatically adjusting the tension of the track provided by the embodiment of the utility model not only adopts a hydraulic energy storage mode to automatically adjust the tension of the track according to working conditions, thereby being suitable for various complex working conditions and having good overall durability; moreover, the system pressure can be automatically calibrated periodically through the first safety oil path 103 and the second oil supply branch path 102, so that the hydraulic system has an automatic protection function and accidents are prevented.

In particular, the first relief valve 4 is provided in the first oil supply branch 101, and the set pressure of the first relief valve 4 is the first pressure value P2.

In specific implementation, the second pressure reducing valve 5 and the first switching valve 6 are disposed in the second oil supply branch 102, the set pressure of the second pressure reducing valve 5 is the second pressure value P3, and the first switching valve 6 is cyclically opened and closed according to a preset period (i.e., short-time conduction is provided in a fixed time period), so that the second oil supply branch 102 is cyclically opened and closed according to the preset period. For example, the first switching valve 6 is set to be electrified every 15 seconds for 2 seconds, and during the electrifying process, the second oil supply branch 102 supplies hydraulic oil with the oil pressure of the second pressure value P3 to act on the subsequent oil path; when the first switch valve 6 is closed, only the first oil supply branch 101 continuously supplies oil and maintains pressure for the subsequent oil path.

In specific implementation, the first relief valve 11 and the second switching valve 10 are disposed in the first relief oil path 103 in series, the second switching valve 10 is a normally closed valve, the set opening pressure of the second switching valve 10 is P3, the set relief pressure value P3', P3' of the first relief valve 11 defines a normal operating pressure calibration value of the expansion device 17, the settable range is P3' ∈ (P2, P4), P4 is a rated pressure stored in the pressure accumulating oil path for balancing pressure variation of the expansion device 17, and when the pressure accumulating oil path is a multi-stage pressure accumulating oil path with multi-stage pressure accumulating capability, P4 is a rated pressure of the lowest stage.

Specifically, P3 'may be preferably adjusted according to the actual working conditions, and in a preferred embodiment, P3' =p3. When the first switching valve 6 is electrified and the second oil supply branch 102 is opened, the second switching valve 10 in the first safety oil path 103 is automatically opened, the system adjusts the pressure through the first overflow valve 11, when the working pressure value PC of the telescopic device 17 is more than P3', the first overflow valve 11 is opened, and the working pressure value PC of the telescopic device 17 is reduced to P3'; when the operating pressure value PC of the telescopic device 17 is less than or equal to P3', the first relief valve 11 is kept closed, and the operating pressure value PC of the telescopic device 17 is kept unchanged.

Specifically, the second switching valve 10 may employ a two-position two-way switching valve, the control oil passage of which is connected to the second oil supply branch 102, or a common outlet oil passage connecting the second oil supply branch 102 and the first oil supply branch 101. When the first switching valve 6 is powered on and the second oil supply branch 102 is in an open state, the control oil path of the second switching valve 10 detects hydraulic oil with a pressure of a second pressure value P3, so as to control the valve body of the second switching valve 10 to be conducted, and the system regulates the pressure through the first relief valve 11.

Specifically, the first switching valve 6 may be a four-position four-way electromagnetic directional valve, or may be other parts capable of achieving a switching action.

Further, in the first oil supply branch 101, the outlet pipe of the first pressure reducing valve 4 is provided with a first check valve 7, and preferably, the first check valve 7 is a sprung check valve; and/or in the second oil supply branch 102, the outlet line of the second relief valve 5 is provided with a second non-return valve 8, preferably the second non-return valve 8 is a sprung non-return valve. By means of the non-return valves 7 and 8, it is ensured that the oil supply functions of the first oil supply branch 101 and the second oil supply branch 102 and the subsequent oil circuit pressure do not influence each other.

In particular, the hydraulic system further comprises a third switch valve 3. As shown in fig. 1, the third switching valve 3 is provided between the common inlet of the first oil supply branch 101 and the second oil supply branch 102 and the oil pump. After the whole machine is electrified, the third switch valve 3 is opened, at the moment, the oil inlet P is communicated with the first connecting port A, and pressure oil with a pressure value of P0 is provided for the whole hydraulic system. After the whole machine is powered off, an oil inlet P of the third switch valve 3 is communicated with the second connecting port B to form a circuit breaker; the first connecting port A is connected with the oil return port T, so that pressure oil in the subsequent pipeline is connected with an oil return tank, and the pressure is released.

In particular, the hydraulic system further comprises a first accumulator 1 and a second relief valve 2. As shown in fig. 1, the first accumulator 1 and the second relief valve 2 are both provided on the oil intake line between the third switching valve 3 and the oil pump, and the set relief pressure of the second relief valve 2 is a third pressure value P0, P0 > P3 > P2. Thus, the hydraulic oil whose initial supply pressure is stabilized at P0 can be supplied to the system through the first accumulator 1 and the second relief valve 2.

In specific implementation, a second safety oil path 104 is also provided in the hydraulic system. As shown in fig. 1, the second relief oil passage 104 is a normally open oil passage connected in parallel with the first relief oil passage 103, and the set relief pressure of the second relief oil passage 104 is greater than the set relief pressure of the first relief oil passage 103.

Specifically, the first relief oil passage 103 is provided with a first relief valve 11, and the set relief pressure (i.e., the pre-set relief pressure) of the first relief valve 11 is the set relief pressure value P3'; the second relief oil passage 104 is provided with a second relief valve 12, and the set relief pressure (i.e., the preset relief pressure) of the second relief valve 12 is a third pressure value P7, P7 > P3'. And, the third pressure value P7 is larger than the maximum oil pressure that can be supplied by the accumulator oil passage 105, that is, larger than the maximum value in the above-described preset pressure value range, to define the maximum pressure of the work implement system (the expansion device 17).

In particular, the energy storage oil path 105 is connected between the oil supply path and the expansion device 17, and includes a first energy storage oil path and a second energy storage oil path that are arranged in parallel. Wherein: the first energy storage oil path is used for storing energy with a pressure value in a first range and can convey the stored energy to the telescopic device 17; the second energy storage oil path is used for storing energy with a pressure value in a second range and can convey the stored energy to the telescopic device 17; the maximum pressure value in the second range is greater than the maximum pressure value in the first range and less than the set relief pressure (i.e., the third pressure value P7) of the second relief valve 12.

Specifically, as shown in fig. 1, a third relief valve 15, a first one-way throttle valve group 16, and a first accumulator 18 are provided in the first accumulator oil passage. The first one-way throttle valve group 16 is connected in parallel with the third pressure reducing valve 15, and the first accumulator 18 is connected in series with the third pressure reducing valve 15. Further, a third check valve 20 is included, the inlet of which is connected to the first accumulator circuit 105, and the outlet of which is connected to the tank through an oil return line and a shut-off valve 22.

Similarly, a fourth pressure reducing valve 13, a second one-way throttle valve group 14 and a second accumulator 19 are arranged in the second energy storage oil path. The second one-way throttle valve group 14 is connected in parallel with the fourth pressure reducing valve 13, and the second accumulator 19 is connected in series with the fourth pressure reducing valve 13. Further, a fourth check valve 21 is included, the inlet of which is connected to the second accumulator circuit, and the outlet of which is connected to the tank through an oil return circuit and a shut-off valve 22.

Therefore, the hydraulic system adopts a double-accumulator structure, so that multistage pressure setting can be realized, and large-range pressure regulation can be realized. When the pressure in the accumulator oil passage and the expansion device is released, the shutoff valve 22 may be opened.

In specific implementation, the telescopic device 17 comprises a telescopic oil cylinder, and a tensioning wheel is rotatably connected to a piston rod of the telescopic oil cylinder and used for adjusting the tensioning force of the crawler belt.

In specific implementation, the hydraulic system is provided with a first telescopic device for adjusting the tensioning force of the first crawler belt and a second telescopic device for adjusting the tensioning force of the second crawler belt; the energy storage oil circuit 105 comprises a first energy storage oil circuit connected with the first telescopic device and a second energy storage oil circuit connected with the first telescopic device; the first energy storage oil path and the second energy storage oil path are arranged at the common outlet of the first oil supply branch 101 and the second oil supply branch 102 in parallel. Referring specifically to fig. 1, two sets of tensioning automatic regulating valve groups (see rectangular dotted line area in fig. 1) are arranged in parallel at the common outlet of the first oil supply branch 101 and the second oil supply branch 102.

In addition, in an embodiment of the present utility model, there is also provided a working machine provided with a crawler running gear in which the hydraulic system for automatically adjusting the crawler tension described above is provided.

Specifically, referring to fig. 1, the hydraulic system for automatically adjusting the tension of the track according to the embodiment of the present utility model includes the following components and functions thereof:

the third accumulator 1: the hydraulic system is regulated and stabilized for the whole track tensioning and adjusting.

Third relief valve 2: the input pressure to the overall track tensioning hydraulic system is defined as P0.

Third switching valve 3: the valve can be an electromagnetic reversing valve; the whole machine is started after being electrified, an oil inlet P of a third switch valve 3 is communicated with a first connecting port A, and pressure oil with a pressure value P0 is provided for the whole hydraulic system; after the whole machine is powered off, an oil inlet P of the third switch valve 3 is communicated with the second connecting port B to form a circuit breaker; the pressure oil between the subsequent pipeline and the one-way valve 9 is connected back to the oil tank, and the pressure is released.

The first pressure reducing valve 4: setting the pressure as P2, and continuously providing low-pressure oil with the pressure value of P2 for the subsequent oil way.

Second pressure reducing valve 5: setting the pressure as P3, and under the combined action of the first switch valve 6, intermittently providing high-pressure oil with the pressure value of P3 for the subsequent oil way.

First switching valve 6: the valve can be an electromagnetic reversing valve; in operation, the first switch valve 6 is set to be turned on for a short time in a fixed period of time, for example, every 15 seconds, and during the power-up process, the second oil supply branch 102 applies the pressure oil with a pressure value of P3 to the subsequent oil path.

First check valve 7: the first oil supply branch 101 is conducted in one direction, and pressure oil with a pressure value of P2 is provided.

Second check valve 8: the second oil supply branch 102 is unidirectionally conducted to supply pressure oil with a pressure value P3.

Fifth check valve 9: the pressure (P2 or P3) of the front oil supply path (namely the first oil supply branch 101 and the second oil supply branch 102 which are connected in parallel) is communicated with the subsequent oil path in a unidirectional way and is arranged in the tensioning valve group, and meanwhile, high-pressure oil of the subsequent pipeline is prevented from channeling into the front oil supply path.

Second switching valve 10: the valve can be a two-position two-way switch valve; setting the opening pressure as P3, when the second oil supply branch 102 is in an open state and the control oil path of the second switching valve 10 detects the pressure P3, controlling the first safety oil path 103 to be conducted, and adjusting the pressure for the hydraulic system.

First relief valve 11: when the relief pressure value is set to P3', and the second on-off valve 10 is in the open state, the line pressure of the expansion device 17 and the line pressure connected thereto can be reduced to P3' by the first relief valve 11, thereby protecting the hydraulic system.

Second relief valve 12: when the relief pressure value is set to be P7 and the expansion device 17 exceeds P7, the relief protection is realized by the second relief valve 12.

Fourth pressure reducing valve 13: the pressure value is set to P6, and when the pressure of the expansion device 17 is lower than P6, the second accumulator 19 is connected.

Second one-way throttle valve group 14: the second accumulator 19 can back-charge the expansion device 17 with pressure via the second one-way throttle valve group 14.

Third pressure reducing valve 15: the pressure value is set to P4, and when the pressure of the expansion device 17 is lower than P4, the first accumulator 18 is connected.

First one-way throttle valve group 16: the first accumulator 18 can back-charge the expansion device 17 with pressure via the first one-way throttle valve group 16.

Telescoping device 17: the crawler tensioning cylinder is generally connected with the tensioning wheel and the frame, and thrust for supporting the tensioning wheel is provided according to the pressure of a subsequent hydraulic system. Most of the working time the cylinder pressure is P3', when the work machine encounters an obstacle, the cylinder contracts, storing the pressure in the first accumulator 18 (at system low pressure) and the second accumulator 19 (at system high pressure).

First accumulator 18: setting the initial pressure as P1, filling nitrogen into the cylinder, and setting the volume as R1, absorbing and releasing low-pressure, and smoothing hydraulic impact.

The second accumulator 19: setting the initial pressure as P5, filling nitrogen, and the volume as R2, absorbing and releasing high-pressure, and smoothing hydraulic impact.

Third check valve 20: one-way conduction low-pressure energy storage oil way.

Fourth check valve 21, the unidirectional conduction high pressure energy storage oil circuit.

Shut-off valve 22: when the system components are regulated during maintenance or the crawler belt is disassembled, the stop valve 22 is opened to release pressure.

The set pressure value of each part has the following relation: p1< P2< P3< P4< P5< P6< P7, P3< P0, P3' ∈ (P2, P4).

In summary, the working process of the hydraulic system for automatically adjusting the tension of the crawler belt provided by the embodiment of the utility model is as follows:

(1) After the third switching valve 3 is opened, the pressure oil having a pressure value P0 is supplied to the first pressure reducing valve 4 and the second pressure reducing valve 5.

(2) The first pressure reducing valve 4 continuously supplies the pressure oil with the pressure P2 to the subsequent system;

the first switch valve 6 is intermittently turned on according to program setting, and provides the pressure oil with the pressure of P3 to a subsequent system.

(3) When the crawler belt has no extra load (for example, the whole machine is stopped stably and in a static state), the hydraulic pressure PC of the telescopic device 17 is P3, and meanwhile, the first energy accumulator 18 stores energy to P3.

(4) When the whole machine stably walks, the load is stable, the impact force is gentle by the first energy accumulator 18, and meanwhile, under the condition that the second switch valve 10 is conducted, the system or the oil overflows through the first overflow valve 11, so that the hydraulic pressure PC of the telescopic device 17 is limited at P3'.

(5) When the crawler belt has additional impact load (for example, the whole machine stably walks and suddenly encounters obstacle), the second switch valve 10 is not conducted, or the first overflow valve 11 is not fast overflowed, the working pressure value PC of the telescopic device 17 suddenly rises:

if PC rises to P4, the pressure of the first accumulator 18 is stored to P4, and the third pressure reducing valve 15 reaches the upper operating limit P4 and closes;

if PC continues to rise, when P5 is reached and exceeded, the second accumulator 19 starts compression accumulation;

if PC continues to rise, when P6 is reached and exceeded, the second accumulator 19 accumulates to P6 and the fourth pressure reducing valve 13 reaches the upper operating limit P6 and closes.

If the PC continues to rise, when P7 is reached, the second relief valve 12 opens, releasing the pressure to the system. The upper limit of the pressure of the whole system is P7, and the system is protected.

(6) When the crawler additional load is suddenly removed, the hydraulic pressure PC of the telescopic device 17 drops rapidly:

when the PC is lower than P6 and higher than P5, the second energy accumulator 19 supplies high-pressure oil for the telescopic device 17;

when PC drops further, to a value greater than P1 and less than P4, the first accumulator 18 provides low pressure oil charge for the telescopic device 17.

(7) When the crawler traveling device needs to release pressure, for example, before the crawler is disassembled, the third switch valve 3 is powered off and closed, the stop valve 22 is opened manually, and the internal oil circuit (oil cylinder, valve bank and energy accumulator) of the whole hydraulic system is communicated with the oil return tank through the third check valve 20 and the fourth check valve 21. The internal pressure of the regulating system drops to zero.

The left and right tracks of the working machine are provided with a set of tensioning valve groups (see rectangular dotted line area in figure 1) and a telescopic device 17, and oil supply of the tensioning valve groups and the telescopic device is from a common oil supply circuit, and reference numerals 1 to 8 in the figure.

Finally, it is further noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present utility model. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the utility model. Thus, the present utility model is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A hydraulic system for automatically adjusting track tension, comprising:

a telescopic device (17) for adjusting the track tension;

a first oil supply branch (101) connected to the telescopic device (17), the first oil supply branch (101) being adapted to supply hydraulic oil having a first pressure value P2;

a second oil supply branch (102) connected in parallel with the first oil supply branch (101) and connected with the telescopic device (17), wherein the second oil supply branch (102) is used for providing hydraulic oil with a second pressure value P3, and can be cyclically opened and closed according to a preset period, and the second pressure value P3 is larger than the first pressure value P2;

an energy storage oil path (105) connected with the telescopic device (17) and used for balancing the pressure change of the telescopic device (17) in a preset pressure value range;

the first safety oil way (103) can be used for releasing pressure for the system when the second oil supply branch (102) is opened, and is in a closed state when the second oil supply branch (102) is closed.

2. The hydraulic system for automatically adjusting the tension of a track according to claim 1, characterized in that a first relief valve (4) is provided in the first oil supply branch (101), the set pressure of the first relief valve (4) being the first pressure value P2;

and/or a second pressure reducing valve (5) and a first switching valve (6) are arranged in the second oil supply branch (102), the set pressure of the second pressure reducing valve (5) is the second pressure value P3, and the first switching valve (6) is used for controlling the second oil supply branch (102) to be opened and closed in a circulating mode according to the preset period.

3. The hydraulic system for automatically adjusting the tensioning force of the crawler belt according to claim 2, wherein a first relief valve (11) and a second switching valve (10) are arranged in series in the first safety oil path (103), the second switching valve (10) is a normally closed valve, the set opening pressure of the second switching valve (10) is the second pressure value P3, the set relief pressure of the first relief valve (11) is a regulated pressure value P3', and the regulated pressure value P3' is larger than the first pressure value P2.

4. A hydraulic system for automatically adjusting the tensioning force of a track according to claim 3, characterized in that the second switching valve (10) is a two-position two-way switching valve, the control oil circuit of which is connected to the second oil supply branch (102) or to an outlet oil circuit common to the second oil supply branch (102) and the first oil supply branch (101).

5. Hydraulic system for automatically adjusting the tensioning force of a track according to claim 2, characterized in that the first switching valve (6) is an electromagnetic directional valve.

6. The hydraulic system for automatically adjusting the tension of a track according to claim 2, characterized in that in the first oil supply branch (101) the outlet of the first relief valve (4) is connected to a first one-way valve (7);

and/or, in the second oil supply branch (102), the outlet of the second pressure reducing valve (5) is connected with a second one-way valve (8).

7. The hydraulic system for automatically adjusting the tension of a track according to claim 1, further comprising a third on-off valve (3);

the third switching valve (3) is arranged between the common inlet of the first oil supply branch (101) and the second oil supply branch (102) and the oil pump.

8. The hydraulic system for automatically adjusting a track tension as recited in claim 7, further comprising:

the first energy accumulator (1) is arranged on an oil inlet pipeline between the third switch valve (3) and the oil pump;

and/or, a second relief valve (2) is arranged on an oil inlet pipeline between the third switch valve (3) and the oil pump, the set relief pressure of the second relief valve (2) is a third pressure value P0, and the third pressure value P0 is larger than the second pressure value P3.

9. The hydraulic system for automatically adjusting a track tension according to claim 1, further comprising a second relief oil circuit (104);

the second safety oil circuit (104) is connected with the first safety oil circuit (103) in parallel;

the set relief pressure of the second relief oil passage (104) is greater than the set relief pressure of the first relief oil passage (103).

10. A work machine comprising a track, further comprising a hydraulic system for automatically adjusting the tension of the track as claimed in any one of claims 1 to 9.