Work machine

Abstract

This working machine may comprise: a left traveling motor; a right traveling motor; a first operator input device for receiving an operator's request (Dmd1) regarding the rotational speed of the left traveling motor; a second operator input device for receiving the operator's request (Dmd2) regarding the rotational speed of the right traveling motor; and a control unit for determining a required driving pattern on the basis of the Dmd1 and the Dmd2 and controlling the volumes of the left driving motor and the right driving motor according to the determined required driving pattern. This working machine may comprise: a left traveling motor; a right traveling motor; a first operator input device for receiving an operator's request (Dmd1) regarding the rotational speed of the left traveling motor; a second operator input device for receiving the operator's request (Dmd2) regarding the rotational speed of the right traveling motor; and a control unit for determining a required driving pattern on the basis of the Dmd1 and the Dmd2.

Description

work machines

[0001] The present disclosure relates to a work machine, and more particularly, to a work machine that recognizes a required driving pattern and a work machine that optimally controls the volumes of driving motors according to the recognized required driving pattern.

[0002]

[0003] Various work machines are known that derive power from pressurized fluids to perform tasks. For example, construction equipment such as excavators are one example. These work machines have left-hand and right-hand drive motors for movement. Therefore, excavators can drive in a straight line, rotate in place, and curve while moving straight with slight turns.

[0004] In order to drive straight, the operator must give the same amount of operation to the first operator input device and the second operator input device, but this is practically impossible, so the operator must carefully watch the direction of travel and operate the first operator input device and the second operator input device. Therefore, straight driving requires the driver's driving operation skills and concentration.

[0005] When performing high-torque stationary or directional turns around curves, the torque must be increased rapidly. However, in machines using variable displacement hydraulic motors as drive motors, the response time required to increase displacement through control makes it relatively difficult to increase torque quickly.

[0006] Therefore, optimal control of the driving motors is necessary depending on the driving pattern. Especially when using a variable displacement motor as the driving motor, it is necessary to ensure that these three driving patterns, each with different loads, can be handled effectively.

[0007]

[0008] According to a first aspect of the present disclosure, a left driving motor; a right driving motor; a first operator input device for receiving Dmd1, which is an operator's request for a rotation speed of the left driving motor; a second operator input device for receiving Dmd2, which is an operator's request for a rotation speed of the right driving motor; and a control unit for determining a desired driving pattern based on Dmd1 and Dmd2, and controlling capacities of the left driving motor and the right driving motor according to the determined desired driving pattern.

[0009] In some embodiments, the control unit may control the volume of the left driving motor and the volume of the right driving motor to have the same value when the required driving pattern is determined to be the straight driving.

[0010] In some embodiments, the control unit may control to increase the volume of the left driving motor and the right driving motor when either the actual differential pressure between the hydraulic pressure of the high pressure side and the hydraulic pressure of the inlet side of the left driving motor and the actual differential pressure between the hydraulic pressure of the high pressure side and the hydraulic pressure of the inlet side of the right driving motor or an average thereof is less than a preset reference differential pressure, and to decrease the volume of the left driving motor and the right driving motor when either the average thereof is greater than the reference differential pressure.

[0011] In some embodiments, the control unit controls the volume of the left driving motor and the volume of the right driving motor to be the same value when the required driving pattern is determined as the stationary rotation, and the same value may be a preset value smaller than the maximum volume of the left driving motor and the right driving motor.

[0012] In some embodiments, the control unit can control the volume of the driving motor corresponding to the larger one of Dmd1 and Dmd2 among the left driving motor and the right driving motor to be the maximum volume when the required driving pattern is determined to be the curved driving.

[0013] In some embodiments, the control unit controls the volume of the left driving motor and the volume of the right driving motor to be the same value when the required driving pattern is determined to be the curved driving, and the same value may be the maximum volume of the left driving motor and the right driving motor.

[0014] In some embodiments, the control unit may control the volume of the left driving motor and the volume of the right driving motor to be the same value when the desired driving pattern is determined to be a stationary rotation, and may control the volume of the driving motor corresponding to the larger one of Dmd1 and Dmd2 among the left driving motor and the right driving motor to be greater than the same value when the desired driving pattern is determined to be a curved driving.

[0015] In some embodiments, the work machine includes a first inlet valve configured to allow or block the inflow of fluid into the left travel motor, a first outlet valve configured to allow or block the outflow of fluid from the left travel motor, a second inlet valve configured to allow or block the inflow of fluid into the right travel motor, and a second outlet valve configured to allow or block the outflow of fluid from the right travel motor, wherein the control unit increases the opening amount of the first inlet valve when the actual rotation speed of the left travel motor is less than the required rotation speed of the left travel motor corresponding to the Dmd1, decreases the opening amount of the first inlet valve when the actual rotation speed of the left travel motor is greater than the required rotation speed of the left travel motor corresponding to the Dmd1, increases the opening amount of the second inlet valve when the actual rotation speed of the right travel motor is less than the required rotation speed of the right travel motor corresponding to the Dmd2, and opens the second inlet valve when the When the actual rotation speed of the right driving motor becomes greater than the required rotation speed, the opening amount of the second inlet valve can be controlled to decrease.

[0016] According to a second aspect of the present disclosure, a driving device may include a left driving motor, a right driving motor, a first operator input device for receiving Dmd1, which is an operator's request for a rotation speed of the left driving motor, a second operator input device for receiving Dmd2, which is an operator's request for a rotation speed of the right driving motor, and a control unit for determining a requested driving pattern based on Dmd1 and Dmd2.

[0017] In some embodiments, the requested driving pattern includes at least straight driving, and the control unit can determine the straight driving at least when Dmd1 ≠ 0, Dmd2 ≠ 0, and Dmd2 = Dmd1.

[0018] In some embodiments, the control unit may determine straight driving when Dmd1 and Dmd2 are in a region where Dmd1 ≠ 0 and Dmd2 ≠ 0 and Dmd2 = Dmd1 or is adjacent to it.

[0019] In some embodiments, the control unit determines the straight driving when 0 < Dmd1, 0 < Dmd2, and Dmd1 - a < Dmd2 < Dmd1 + a, or Dmd1 < 0, Dmd2 < 0, and Dmd1 - a < Dmd2 < Dmd1 + a, where a can be a positive integer.

[0020] In some embodiments, the requested driving pattern includes at least a stationary rotation, and the control unit can determine the stationary rotation at least when Dmd1 ≠ 0, Dmd2 ≠ 0, and Dmd2 = - Dmd1.

[0021] In some embodiments, the control unit may determine that Dmd1 and Dmd2 are in a rotation-in-place state when Dmd1 ≠ 0 and Dmd2 ≠ 0 and Dmd2 = - Dmd1 or are in their adjacent regions.

[0022] In some embodiments, the control unit determines the in-place rotation when 0 < Dmd1, Dmd2 < 0, - Dmd1 - b < Dmd2 < - Dmd1 + b, or when Dmd1 < 0, 0 < Dmd2, - Dmd1 - b < Dmd2 < - Dmd1 + b, where b can be a positive integer.

[0023] In some embodiments, the desired driving pattern may include at least curved driving.

[0024] In some embodiments, the control unit is configured such that 0 < Dmd1, 0 < Dmd2, and Dmd2 < Dmd1 - a, or 0 < Dmd1, 0 < Dmd2, and Dmd1 + a < Dmd2, or 0 < Dmd1, Dmd2 < 0, and - Dmd1 + b < Dmd2, or 0 < Dmd1, Dmd2 < 0, and Dmd2 < - Dmd1 - b, or Dmd1 < 0, Dmd2 < 0, and Dmd1 + a < Dmd2, or Dmd1 < 0, Dmd2 < 0, and Dmd2 < Dmd1 - a, or Dmd1 < 0, 0 < Dmd2, and - Dmd1 + b < Dmd2, or Dmd1 < 0, 0 < Dmd2, and Dmd2 < - Dmd1 - b, the curve is determined by driving, where a and b can be positive integers.

[0025] In some embodiments, a < b may be true.

[0026] In some embodiments, the first operator input device and the second operator input device are hydraulic or electric driving levers or driving pedals, and the magnitude of the pressure of the hydraulic signal or the magnitude of the current of the electric signal, which varies depending on the amount of operation of the driving levers or the driving pedals, can be input to the Dmd1 and the Dmd2.

[0027] In some embodiments, the work machine may include a first inlet valve configured to allow or block fluid communication between a high pressure side, a low pressure side, and an inlet side of the left drive motor, a first outlet valve configured to allow or block fluid communication between the outlet side of the left drive motor and the low pressure side, a second inlet valve configured to allow or block fluid communication between the high pressure side and the inlet side of the right drive motor, and a second outlet valve configured to allow or block fluid communication between the outlet side of the right drive motor and the low pressure side.

[0028] In some embodiments, the high pressure side may include at least one high pressure accumulator, and the low pressure side may include at least one low pressure accumulator.

[0029] According to the above configuration, there is an advantage in that a work machine having a quick response characteristic to the operator's request can be provided by recognizing a driving pattern according to the operator's request and controlling the volume of the driving motor to a preset value according to the recognized driving pattern.

[0030]

[0031] The above aspects, the appended claims and the examples disclosed herein, either before or after, may be suitably combined with each other, as will be apparent to a person of ordinary skill in the art.

[0032] Additional features and advantages are disclosed in the following description, claims, and drawings, and to some extent will be readily apparent to those skilled in the art or may be learned by practicing the teachings described herein.

[0033]

[0034] FIG. 1 is a drawing schematically showing the appearance of a working machine according to an example of the present disclosure.

[0035] Figure 2 is a schematic diagram illustrating stationary rotation and curved driving.

[0036] Figure 3 is a drawing showing the relationship between the first demand and the second demand and the driving pattern.

[0037] Figure 4 is a block diagram of a hydraulic system of a work machine according to an example of the present disclosure.

[0038] Fig. 5 is a partially enlarged view of the hydraulic system of Fig. 4 showing an example of valve arrangement.

[0039] Figure 6 is a conceptual diagram showing volume control of a driving motor during straight driving of a working machine according to an example of the present disclosure.

[0040] FIG. 7 is a conceptual diagram showing the control of the opening amount of the first inlet valve and the second inlet valve performed in a working machine according to an example of the present disclosure.

[0041]

[0042] Aspects of the present disclosure, cited as examples, are described in detail below with reference to the accompanying drawings. The aspects described below provide the information necessary to enable a person of ordinary skill in the art to implement the present disclosure.

[0043] The present disclosure is applicable to work machines in the fields of industrial construction machinery, material handling machinery, or construction equipment, particularly wheel loaders and excavators. While the present disclosure will primarily be described with respect to excavators, the present disclosure is not limited to this particular machine, and can be used in any work machine including a hydraulic system, particularly a hydraulic system having a high-pressure side and a low-pressure side as described below, such as wheel loaders, articulated or rigid haulers, and backhoe loaders.

[0044] Hydraulic systems are used in a variety of applications. For example, work machines typically rely on hydraulic systems to provide power to handle loads. Hydraulic systems for work machines may include various hydraulic actuators, such as hydraulic cylinders and hydraulic motors. Hydraulic cylinders may be provided to operate work devices, such as arms and buckets. Hydraulic motors may be used, for example, to propel and / or swing the work machine.

[0045]

[0046] FIG. 1 is a drawing schematically showing the appearance of a working machine according to an example of the present disclosure.

[0047] The work machine (10) may include a hydraulic system (12) according to the present invention. In Fig. 1, the work machine (10) is exemplified as an excavator.

[0048] The work machine (10) may include an upper swing structure (14), a lower driving structure (16), and a work device (18).

[0049] The upper swing structure (14) may include a cap (20) and a swing device (23) that rotates the load. The swing device (23) may perform a function of rotating the upper swing structure (14) relative to the lower driving structure (16). The swing device (23) may include a swing motor.

[0050] The lower driving structure (16) may include a driving device (25) for driving each crawler track. The driving device (25) may include a left driving motor and a right driving motor.

[0051] The working device (18) may include a boom (26), an arm (28), and a bucket (30). The working device (18) may further include two boom cylinders (32) (only one is visible in FIG. 1), an arm cylinder (34), and a bucket cylinder (36). The boom cylinder (32) may be operable between the upper swing structure (14) and the boom (26). The arm cylinder (34) may be operable between the boom (26) and the arm (28). The bucket cylinder (36) may be operable between the arm (28) and the bucket (30).

[0052] In addition, the work machine (10) may include a first operator input device that receives a first request, Dmd1, for the rotation speed of the left driving motor and a second operator input device that receives a second request, Dmd2, for the rotation speed of the right driving motor. The first operator input device and the second operator input device may be provided in the cab (20). In some examples, the first operator input device and the second operator input device may have the form of a lever or a pedal, but the present disclosure is not limited thereto and may have various other forms. The first operator input device and the second operator input device may be a hydraulic input device that receives an operator's operation as a hydraulic signal or an electrical input device that receives an operator's operation as an electrical signal. That is, the first operator input device and the second operator input device may receive, as Dmd1 and Dmd2, the magnitude of the pressure of the hydraulic signal or the magnitude of the current of the electrical signal, which vary depending on the amount of operation of the input device. Therefore, in this specification, Dmd1 and Dmd2 may be used to refer to any one of the driver's request, the amount of operation of the input device, the magnitude of the pressure of the hydraulic signal, and the magnitude of the current of the electric signal, which are equivalent to each other.

[0053] In addition, the work machine (10) may include a control unit that determines a driving pattern based on Dmd1 and Dmd2 and controls the capacities of the left driving motor and the right driving motor according to the determined driving pattern. When hydraulic input devices are used as the first operator input device and the second operator input device, the work machine (10) requires a hydraulic sensor for measuring the size of a hydraulic signal input to the input device (i.e., generated by the input device), and the hydraulic sensor can transmit the size of the measured hydraulic signal to the control unit as an electrical signal. When electrical input devices are used as the first operator input device and the second operator input device, the electrical input device can directly transmit the electrical signal input to the input device (i.e., generated by the input device) to the control unit.

[0054] Additionally, the work machine (10) may include regulators (not shown) for adjusting the capacities of the left and right drive motors by changing the inclination angles of the swash plate of the left drive motor and the swash plate of the right drive motor. Additionally, the work machine (10) may include electronic proportional pressure reducing valves (not shown) that receive an electric signal from a control unit and are switched to apply a hydraulic signal to the regulators to operate the regulators.

[0055]

[0056] Figure 2 is a schematic diagram illustrating stationary rotation and curved driving.

[0057] The driving pattern of the work machine can broadly include at least one of straight driving, standing still (Fig. 2 (a)), and curved driving (Fig. 2 (b)). In Fig. 2, 25l indicates the left track or left wheel, and 25r indicates the right track or right wheel. Additionally, the arrows indicate the torque applied to each track or wheel.

[0058] When the desired driving pattern requested by the driver is determined (recognized) to be straight driving, the control unit can control the volume of the left driving motor and the volume of the right driving motor to have the same value. Since the torque applied to the left driving motor and the right driving motor is the same when driving straight, the control unit can control the inclination angle of the swash plate of the left driving motor and the inclination angle of the swash plate of the right driving motor to be the same, thereby making the volume of the left driving motor and the volume of the right driving motor the same.

[0059] When the desired driving pattern requested by the driver is determined (recognized) to be a standing still, the control unit controls the volume of the left driving motor and the volume of the right driving motor to have the same value, and the same value may be a value smaller than the maximum volume of the left driving motor and the right driving motor. Since a standing still requires less torque than a curved driving, the control unit controls the inclination angle of the swash plate of the left driving motor and the inclination angle of the swash plate of the right driving motor to have a value smaller than the maximum, so that the volume of the left driving motor and the volume of the right driving motor may have a value smaller than the maximum. The value smaller than the maximum may be given as a preset constant value.

[0060] In the case of a standing still, the left and right driving motors must output the same torque in opposite directions, but in the case of curved driving, they must output torque in the same direction, but the inside driving motor must reduce speed but drive straight, and the outside driving motor must output higher torque than the inside driving motor to create a rotation, so a high torque is required. Therefore, when the required driving pattern is recognized (determined) as curved driving, the volume of the driving motor corresponding to at least the larger one of Dmd1 and Dmd2 among the left and right driving motors (the right driving motor in (b) of Fig. 2) can be controlled to have the maximum volume.

[0061] In some embodiments, the volume of the drive motor corresponding to the smaller one of Dmd1 and Dmd2 (the left drive motor in (b) of Fig. 2) may be given a preset constant value smaller than the maximum volume. In some other embodiments, the hydraulic pressure (P) of the high pressure side h ) and the inlet pressure (P) of the driving motor (left driving motor in (b) of Fig. 2) corresponding to the smaller one of Dmd1 and Dmd2 i ) pressure difference (ΔP = P h - P i ) of the actual differential pressure (ΔP act ) and the preset reference pressure difference (ΔP ref ), comparing the actual differential pressure (ΔP act ) is the preset reference pressure difference (ΔP ref ) becomes smaller than the volume (D) of the driving motor (the left driving motor in (b) of Fig. 2) m ) to generate a signal that increases the actual differential pressure (ΔP act ) is the reference pressure (ΔP ref ) becomes larger than the volume (D) of the driving motor (the left driving motor in (b) of Fig. 2) m ) can be controlled by a control unit (74) to generate a signal to reduce the hydraulic motor.

[0062] In some alternative embodiments, when the desired driving pattern requested by the driver is determined (recognized) to be curved driving, the control unit controls the volume of the left driving motor and the volume of the right driving motor to have the same value, and the same value may be the maximum volume of the left driving motor and the right driving motor. In order for the driving motor to have the maximum volume, the control unit may control the inclination angle of the swash plate of the driving motor to be maximum. That is, when the desired driving pattern is determined to be curved driving, the volume of the driving motor corresponding to the smaller one of Dmd1 and Dmd2 (the left driving motor in FIG. 2 (b)) may also be controlled to have the maximum volume equal to the volume of the driving motor corresponding to the larger one of Dmd1 and Dmd2 (the right driving motor in FIG. 2 (b)).

[0063] In some embodiments, when the desired driving pattern is determined to be a standing turn, the volume of the left driving motor and the volume of the right driving motor are controlled to have the same value, and when the desired driving pattern is determined to be a curved driving, the volume of the driving motor corresponding to the larger one of Dmd1 and Dmd2 among the left and right driving motors can be controlled to be larger than the same value, and the larger value can be smaller than the maximum volume, unlike the previous embodiments. Here, the volume of the driving motor corresponding to the smaller one of Dmd1 and Dmd2 can be controlled to have the same value as the volume of the driving motor corresponding to the larger one, or can be controlled to have a smaller value.

[0064] In conclusion, the volume value is also proportional to the torque demand in the order of standing rotation < curved driving. In the case of straight driving, instead of providing a constant volume value as described above, the volume value can be controlled to vary according to the required torque.

[0065] By operating the first and second operator input devices, the driver's desired driving pattern is distinguished, and the driving motor is controlled differently accordingly. This ensures that straight driving is important, and enables rapid generation of high torque in the case of turning in place and driving on curves. This allows for three driving modes with different loads to be handled effectively when using a variable displacement driving motor.

[0066] In a work machine that does not have such an optimal volume control configuration, for example, even if an operator requests curved driving, the work machine does not increase the volume immediately, but only when it determines, for example, that torque needs to be increased by sensing pressure, and thus the responsiveness to the operator's request may be relatively slow. In other words, even if the operator requests curved driving and operates the operator input device, the actual work machine may not be able to immediately perform the intended curved driving due to the lack of torque. In contrast, in a work machine that performs optimal volume control according to an embodiment of the present disclosure, a driving pattern is recognized according to an operator's request, and the volume of the driving motor is immediately controlled to a preset value according to the recognized driving pattern, thereby providing a work machine that has a quick response characteristic to the operator's request.

[0067]

[0068] Figure 3 is a drawing showing the relationship between the first demand and the second demand and the driving pattern.

[0069] As described above, the work machine may include a first operator input device for controlling the rotation speed of the left driving motor for driving operation and a second operator input device for controlling the rotation speed of the right driving motor.

[0070]

[0071] In some examples, the control unit can determine (recognize) straight driving when at least Dmd1 ≠ 0 and Dmd2 ≠ 0, and Dmd2 = Dmd1. In some of these embodiments, the control unit can determine straight driving when Dmd1 and Dmd2 are in the same region as Dmd1 ≠ 0, Dmd2 ≠ 0, and Dmd2 = Dmd1 or are adjacent thereto.

[0072] The following expressions are equivalent to each other as mentioned above.

[0073] - Dmd2 = Dmd1;

[0074] - The amount of manipulation of the second operator input device = the amount of manipulation of the first operator input device; and

[0075] - The size of the electric (or hydraulic) signal input to the second operator input device (or generated by the second operator input device) = The size of the electric (or hydraulic) signal input to the first operator input device (or generated by the first operator input device)

[0076] In Fig. 3, the horizontal and vertical axes represent the amount of manipulation of the input device, and for example, 100 represents when the lever is pushed to the maximum to request the maximum forward speed of the driving motor, and -100 represents when the lever is pulled to the maximum to request the maximum backward speed of the driving motor.

[0077] Furthermore, in some of these examples, the control unit, as illustrated in region I in FIG. 3,

[0078] 0 < Dmd1, 0 < Dmd2, and Dmd1 - a < Dmd2 < Dmd1 + a, or

[0079] When Dmd1 < 0, Dmd2 < 0, and Dmd1 - a < Dmd2 < Dmd1 + a,

[0080] It can be determined as straight driving. Here, a can be a positive integer. a can be adjusted to a preset value. As mentioned above, for straight driving, the amount of operation of the left and right drive levers must be equal. However, in reality, this is very difficult. Therefore, if the difference in the amount of operation of the left and right drive levers is within an acceptable range, the driver is recognized as requesting straight driving, and the capacities of the left and right drive motors are controlled equally.

[0081] In some examples, the control unit can determine a rotation in place when at least Dmd1 ≠ 0, Dmd2 ≠ 0, and Dmd2 = - Dmd1. In some of these embodiments, the control unit can determine a rotation in place when Dmd1 and Dmd2 are in the region of Dmd1 ≠ 0, Dmd2 ≠ 0, and Dmd2 = - Dmd1, or are adjacent thereto.

[0082] Furthermore, in some of these examples, the control unit, as illustrated in area II in FIG. 3,

[0083] 0 < Dmd1, Dmd2 < 0, - Dmd1 - b < Dmd2 < - Dmd1 + b, or

[0084] When Dmd1 < 0, 0 < Dmd2, and - Dmd1 - b < Dmd2 < - Dmd1 + b,

[0085] It can be determined by in-place rotation, where b can be a positive integer. b can be adjusted to a preset value.

[0086] In some examples, the control unit, as illustrated in area III in FIG. 3,

[0087] 0 < Dmd1, 0 < Dmd2, and Dmd2 < Dmd1 - a, or

[0088] 0 < Dmd1, 0 < Dmd2, and Dmd1 + a < Dmd2, or

[0089] 0 < Dmd1, Dmd2 < 0, - Dmd1 + b < Dmd2, or

[0090] 0 < Dmd1, Dmd2 < 0, Dmd2 < - Dmd1 - b, or

[0091] Dmd1 < 0, Dmd2 < 0, and Dmd1 + a < Dmd2, or

[0092] Dmd1 < 0, Dmd2 < 0, Dmd2 < Dmd1 - a, or

[0093] Dmd1 < 0, 0 < Dmd2, - Dmd1 + b < Dmd2, or

[0094] When Dmd1 < 0, 0 < Dmd2, and Dmd2 < - Dmd1 - b,

[0095] It can be determined by driving on a curve.

[0096] A point not mentioned above can be determined as one of the adjacent areas according to a preset condition. For example, when 0 < Dmd1, 0 < Dmd2, and Dmd2 = Dmd1 + a, which are the boundaries between straight driving and curved driving, the point can be determined as one of straight driving and curved driving according to a preset condition.

[0097]

[0098] Figure 4 is a block diagram of a hydraulic system of a work machine according to an example of the present disclosure.

[0099] The hydraulic system (12) may include a high-pressure side (38) and a low-pressure side (40). A hydraulic system including a dedicated high-pressure side and a dedicated low-pressure side may be referred to as a dual-pressure hydraulic system. Advantages associated with a dual-pressure hydraulic system include, for example, improved energy efficiency and controllability.

[0100] In the example of FIG. 4, the high pressure side (38) and the low pressure side (40) may be arranged in a common pressure rail (CPR) architecture. The high pressure side (38) may include a high pressure rail and the low pressure side (40) may include a low pressure rail. The high pressure side (38) and the low pressure side (40) may alternatively be referred to as a high pressure circuit and a low pressure circuit, respectively. The high pressure side (38) and the low pressure side (40) may form a dual pressure system, each including charging circuits of different pressure levels.

[0101] The high pressure side (38) can be connected to the hydraulic motor (60, 62) and the hydraulic cylinder (32, 34, 36) via inlet valves to introduce working fluid into the hydraulic motor (60, 62) and the hydraulic cylinder (32, 34, 36), and the hydraulic motor (60, 62) and the hydraulic cylinder (32, 34, 36) can be connected to the low pressure side (40) via outlet valves to discharge working fluid from the hydraulic motor (60, 62) and the hydraulic cylinder (32, 34, 36).

[0102] During operation of the hydraulic system (12), the pressure of the high pressure side (38) is higher than the pressure of the low pressure side (40). The pressure of the high pressure side (38) is maintained higher than the pressure of the low pressure side (40), although these pressure levels may vary somewhat during operation of the hydraulic system (12). The high pressure of the high pressure side (38) may be, for example, 200 to 350 bar±10%, for example, 250 bar±10%, during operation of the hydraulic system (12). The low pressure of the low pressure side (40) may be, for example, 15 to 30 bar±10%, during operation of the hydraulic system (12). The high pressure of the high pressure side (38) may be, for example, 330 bar when the boom (26) is in the low position and 200 bar when the boom (26) is in the high position.

[0103] The hydraulic system (12) may further include at least one high pressure hydraulic energy storage (42) and at least one low pressure hydraulic energy storage (44). The high pressure hydraulic energy storage (42) may be connected to the high pressure side (38) and the low pressure hydraulic energy storage (44) may be connected to the low pressure side (40). In FIG. 4, each of the high pressure hydraulic energy storage (42) and the low pressure hydraulic energy storage (44) is illustrated as an accumulator. The high pressure hydraulic energy storage (42) may store / release hydraulic energy from / to the high pressure side (38). The low pressure hydraulic energy storage (44) may store / release hydraulic energy from / to the low pressure side (40).

[0104] The hydraulic system (12) may further include a main pump (46). In FIG. 4, the main pump (46) may be connected to the high pressure side (38). The main pump (46) may be arranged to pressurize the high pressure side (38). The main pump (46) is exemplified here as a variable displacement hydraulic motor that operates as both a pump and a motor.

[0105] The hydraulic system (12) may further include an auxiliary pump (48). In the example of FIG. 4, the auxiliary pump (48) may be arranged to supply pressurized fluid from the tank (50) to the low pressure side (38). The auxiliary pump (48) in this example is a fixed displacement pump.

[0106] The main pump (46) and the auxiliary pump (48) can be driven by the power source (52) of the work machine (10). The power source (52) can include, for example, an internal combustion engine or an electric motor.

[0107] The hydraulic system (12) may further include a pressure relief valve (54) connected between the high pressure side (38) and the low pressure side (40) and the tank (50).

[0108] The hydraulic system (12) may further include variable displacement hydraulic motors (60, 62). The hydraulic motor (60) is arranged to rotate a load (22) and each of the two hydraulic motors (62) is arranged to rotate a respective load (24). Each hydraulic motor (60, 62) may have a displacement that varies between 0% and 100%. The hydraulic system (12) should be able to control the rotational speed of each hydraulic motor (60, 62) while the pressure on the high pressure side (38) is maintained within the high pressure range.

[0109] The hydraulic system (12) may further include three gear boxes (64). Each gear box (64) is positioned between a hydraulic motor (60, 62) and a rotating load (22, 24), and may be driven by a drive shaft (66) of each hydraulic motor (60, 62).

[0110] The swing device (23) of Fig. 1 can be implemented by including a variable volume hydraulic motor (60) and a gear box (64). The driving device (25) of Fig. 1 can be implemented by including a variable volume hydraulic motor (62) and a gear box (64).

[0111] The hydraulic system (12) may further include three valve arrangements (68). Each valve arrangement (68) may be in fluid communication with a high pressure side (38), a low pressure side (40), a first port or first side (70) of an associated hydraulic motor (60, 62), and a second port or second side (72) of an associated hydraulic motor (60, 62).

[0112] Additionally, each valve arrangement (68) can be configured to selectively establish fluid communication between the high pressure side (38) and the first side (70), to selectively establish fluid communication between the high pressure side (38) and the second side (72), to selectively establish fluid communication between the low pressure side (40) and the first side (70), and to selectively establish fluid communication between the low pressure side (40) and the second side (72). Accordingly, each valve arrangement (68) can be configured to switch fluid communication between the high pressure side (38) and the first side (70) to fluid communication between the high pressure side (38) and the second side (72).

[0113] The hydraulic cylinders (32, 34, 36) may also be configured so that the inlet side can be in fluid communication with the high pressure side through an inlet valve (not shown), and the outlet side can be configured so that the outlet side can be in fluid communication with the low pressure side through an outlet valve (not shown).

[0114] The hydraulic system (12) may include a first operator input device (75) and a second operator input device (77) configured to receive an operator's request for the rotation speed of the hydraulic motors (62). The operator input device may be provided in the form of a lever or a pedal, for example, but the present disclosure is not limited thereto.

[0115] The hydraulic system (12) may include an operator input device (not shown) configured to receive an operator's request for the rotation speed of the hydraulic motor (60).

[0116] The hydraulic system (12) may include an operator input device (not shown) configured to receive an operator's request for the operation of the hydraulic cylinders (32, 34, 36).

[0117] The hydraulic system (12) may further include a control unit (74). The control unit (74) includes a data processing device and a memory storing a computer program, and the computer program may include program codes that, when executed by the data processing device, cause the data processing device to perform various steps or execute various steps of instructions as described herein.

[0118] In some examples, the hydraulic system may be a hybrid hydraulic system, which may be used to reduce fuel consumption of, for example, an internal combustion engine by recovering energy in the working fluid exhausted from the hydraulic actuator.

[0119]

[0120] Fig. 5 is a partially enlarged view of the hydraulic system (12) of Fig. 4, showing an example of a valve arrangement (68). With reference to Fig. 5, a method of controlling a rotating load (24) by the hydraulic system (12) will be described. The rotating load (22) can also be controlled in the same manner.

[0121] As illustrated in FIG. 5, the control unit (74) is arranged to receive a request (76) for the rotational speed of the hydraulic motor (62) input to the operator input device (75, 77), a signal representing the rotational speed of the hydraulic motor (62), and signals representing the pressures of the high pressure side (38), the low pressure side (40), the first side (70), and the second side (72). The control unit (74) may be configured to control the valve arrangement (68) and to control the volume of the hydraulic motor (62) by the volume controller (78). The volume controller (78) may include the aforementioned regulator and electronic proportional valve.

[0122] The valve arrangement (68) of the present example may include four electro-hydraulic proportional valves (80a to 80d). Each valve (80a to 80d) includes a plurality of different positions that set a plurality of different opening areas. The first valve (80a) is disposed between the high pressure side (38) and the first side (70). The second valve (80b) is disposed between the high pressure side (38) and the second side (72). The third valve (80c) is disposed between the low pressure side (40) and the first side (70). The fourth valve (80d) is disposed between the low pressure side (40) and the second side (72). The valve arrangement (68) of the example of FIG. 5 may further include a controller (82), for example, a PWM (Pulse Width Modulation) controller, for controlling the valves (80a to 80d) based on a command from a control unit (74).

[0123] The second valve (80b) and the third valve (80c) can be closed, and the open area of ​​the first valve (80a) and the open area of ​​the fourth valve (80d) can be controlled to control the rotation of the rotation load (24) in the first direction. In this case, the first valve (80a) functions as an inlet valve (80i), the fourth valve (80d) functions as an outlet valve (80o), and the first side (70) is in fluid communication with the high-pressure side (38) as an inlet side, and the second side (72) is in fluid communication with the low-pressure side (40) as an outlet side.

[0124] In addition, the first valve (80a) and the fourth valve (80d) can be closed, and the open area of ​​the second valve (80b) and the open area of ​​the third valve (80c) can be controlled to control the rotation of the rotation load (24) in a second direction opposite to the first direction. In this case, the second valve (80b) functions as an inlet valve (80i), the third valve (80c) functions as an outlet valve (80o), and the second side (72) communicates with the high-pressure side (38) as an inlet side, and the first side (70) communicates with the low-pressure side (40) as an outlet side.

[0125]

[0126] Figure 6 is a conceptual diagram showing volume control of a driving motor during straight driving of a working machine according to an example of the present disclosure.

[0127] In one example of the present disclosure, when straight driving is determined, the volume of the hydraulic motor (D m ) as shown in Fig. 6, the hydraulic pressure (P) on the high pressure side h ) and the inlet pressure (P) of the left hydraulic motor i ) pressure difference (ΔP = P h - P i ) of the actual differential pressure (ΔP act ) and the hydraulic pressure on the high pressure side (P h ) and the inlet pressure (P) of the right hydraulic motor i ) pressure difference (ΔP = P h - P i ) of the actual differential pressure (ΔP act ) or their average values ​​and a preset reference pressure difference (ΔP ref ), by comparing the above one or their average values ​​to a preset reference pressure difference (ΔP ref ) is smaller than the hydraulic motor volume (D m ) generates a signal that increases the reference differential pressure (ΔP), and one or more of these average values ​​are ref ) is larger than the hydraulic motor's volume (D m ) can be performed by the control unit (74) to control the hydraulic motor, which generates a signal to reduce the differential pressure (ΔP). That is, assuming that the Ph is maintained at a fixed value, the actual differential pressure (ΔP act ) is the preset reference pressure difference (ΔP ref ) is smaller than the hydraulic motor's volume (D m ) to increase the inlet pressure (P i ) to generate a signal that lowers the actual differential pressure (ΔP act ) is the reference pressure (ΔP ref ) is larger than the hydraulic motor's volume (D m ) to reduce the inlet pressure (P i) can be controlled by a control unit (74) to generate a signal to increase the hydraulic motor. The control unit (74) can transmit the generated control signal to the hydraulic motor (62) (volume controller (78)).

[0128] Here, the hydraulic motor may be a driving actuator that drives the work machine, such as a driving motor. The reference differential pressure may be a preset differential pressure based on driving on a flat surface. In other words, the differential pressure normally obtained when driving on a flat surface may be the reference differential pressure (ΔP ref ) can be set. Therefore, the actual differential pressure (ΔP act ) is the reference pressure (ΔP ref ) may be considered as driving on an uphill slope rather than on flat ground.

[0129] In some embodiments, when the average value of the actual differential pressure between the hydraulic pressure on the high pressure side and the hydraulic pressure on the inlet side of the left drive motor and the actual differential pressure between the hydraulic pressure on the high pressure side and the hydraulic pressure on the inlet side of the right drive motor is less than a preset reference differential pressure, the volumes of the left drive motor and the right drive motor can be controlled to increase, and when the average value is greater than the reference differential pressure, the volumes of the left drive motor and the right drive motor can be controlled to decrease.

[0130]

[0131] FIG. 7 is a conceptual diagram showing the control of the opening amount of the first inlet valve and the second inlet valve performed in a working machine according to an example of the present disclosure.

[0132] As described above, the work machine (10) may include a first inlet valve installed on the inlet side of the left driving motor and configured to allow or block the inflow of fluid into the left driving motor, a first outlet valve installed on the outlet side of the left driving motor and configured to allow or block the outflow of fluid from the left driving motor, a second inlet valve installed on the inlet side of the right driving motor and configured to allow or block the inflow of fluid into the right driving motor, and a second outlet valve installed on the outlet side of the right driving motor and configured to allow or block the outflow of fluid from the right driving motor.

[0133] The required rotation speed (V) of the hydraulic motor corresponding to the request entered into the operator input device dmd ) than the actual rotational speed of the hydraulic motor (V act ) compared to the required rotational speed (V dmd ) than the actual rotational speed (V act ) becomes smaller, the opening of the inlet valve, for example, the valve capacity coefficient (K vi ) and generates a signal to increase the required rotational speed (V dmd ) than the actual rotational speed (V act ) increases, the opening amount, for example, the valve capacity coefficient (K Vi ) can be performed by the control unit to generate a signal for reducing the valve pressure. The control unit can transmit the generated control signal to the inlet valve (80i) (controller (82)).

[0134]

[0135] In addition, the present disclosure provides a method for controlling a work machine, which determines a required driving pattern based on the Dmd1 and the Dmd2, and controls the capacities of the left driving motor and the right driving motor according to the determined required driving pattern.

[0136]

[0137] In addition, the present disclosure discloses a control unit comprising a processing circuit configured to perform the method described above, and a computer program comprising a program code for performing the method described above when executed on the processing circuit of a computer or control unit.

[0138] The processing circuitry is provided using one or more combinations of a suitable central processing unit (CPU), multiprocessor, microcontroller, digital signal processor (DSP), etc., capable of executing software instructions stored in a computer program product, for example, in the form of a storage medium. The processing circuitry may further be provided as at least one application-specific integrated circuit (ASIC) or field-programmable gate array (FPGA).

[0139] In particular, the processing circuit is configured to cause the control unit to perform a set of operations or steps, such as the methods described above. For example, the storage medium may store the set of operations, and the processing circuit may be configured to retrieve the set of operations from the storage medium so that the control unit may perform the set of operations. The set of operations may be provided as a set of executable instructions. Accordingly, the processing circuit is configured to perform the methods disclosed herein.

[0140] The storage medium may also include persistent storage, which may be one or a combination of, for example, magnetic memory, optical memory, solid state memory, or further, remotely mounted memory.

[0141] The control unit may further include an interface for communicating with external devices. Accordingly, the interface may include an appropriate number of ports for wireline or wireless communication, and one or more transmitters and receivers containing analog and digital components.

[0142] The processing circuit controls the general operation of the control unit, for example, by sending data and control signals to the interface and storage media, receiving data and reports from the interface, and retrieving data and commands from the storage media. Other components, as well as the relevant functions of the control node, are omitted to avoid obscuring the concepts presented herein.

[0143] A computer-readable medium and program code together can form a computer program product.

[0144]

[0145] The terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the present disclosure. The singular form includes the plural form unless the context clearly dictates otherwise. Furthermore, the term "and / or" includes any and all combinations of one or more of the associated listed items. The term "comprising" or "including" specifies the presence of stated features, integers, steps, operations, elements, and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0146] Comparative terms such as "below," "above," "further above," "further down," "horizontal," or "vertical" may be used herein to describe the relationship of any element depicted in the drawings to other elements. These terms and the foregoing may encompass other orientations of the device in addition to the orientation depicted in the drawings. When an element is referred to as being connected or coupled to another element, this may not only be a direct connection, but may also involve other intervening elements. Conversely, when an element is referred to as being directly connected or coupled to another element, this means that no intervening elements are present.

[0147] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. Terms used herein should be interpreted to have a meaning consistent with their meaning in the context of this specification and the relevant art, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0148] The present disclosure is not limited to the aspects described above and illustrated in the drawings. Rather, those of ordinary skill in the art will appreciate that various changes and modifications can be made within the scope of the present disclosure and the appended claims. Many aspects have been disclosed in the drawings and specification for illustrative purposes, not for purposes of limitation, and the scope of the present inventive concepts is set forth in the following claims.

Claims

1. Left driving motor, Right drive motor; A first operator input device that receives Dmd1, which is an operator's request for the rotation speed of the left driving motor, A second operator input device that receives Dmd2, which is the operator's request for the rotation speed of the right driving motor; A control unit that determines a required driving pattern based on the Dmd1 and the Dmd2 and controls the volumes of the left driving motor and the right driving motor according to the determined required driving pattern. Work machinery.

2. In paragraph 1, The above control unit, When the above required driving pattern is determined to be straight driving, Controlling the volume of the left driving motor and the volume of the right driving motor to have the same value, Work machinery.

3. In paragraph 2, The above control unit, When either the actual differential pressure between the hydraulic pressure of the high pressure side and the hydraulic pressure of the inlet side of the left driving motor and the actual differential pressure between the hydraulic pressure of the high pressure side and the hydraulic pressure of the inlet side of the right driving motor or an average value thereof becomes smaller than a preset reference differential pressure, the volumes of the left driving motor and the right driving motor are controlled to be increased, and when either the average value thereof becomes larger than the reference differential pressure, the volumes of the left driving motor and the right driving motor are controlled to be decreased. Work machinery.

4. In paragraph 1, The above control unit, When the above required driving pattern is determined as a rotation in place, Controlling the volume of the left driving motor and the volume of the right driving motor to be the same value, and the same value is a preset value smaller than the maximum volume of the left driving motor and the right driving motor. Work machinery.

5. In paragraph 1, The above control unit, When the above required driving pattern is determined as curved driving, Among the left driving motor and the right driving motor, the driving motor corresponding to the larger one of the Dmd1 and the Dmd2 is controlled to have the maximum volume. Work machinery.

6. In paragraph 5, The above control unit, When the above-mentioned required driving pattern is determined as the above-mentioned curve driving, Controlling the volume of the left driving motor and the volume of the right driving motor to be the same value, and the same value is the maximum volume of the left driving motor and the right driving motor. Work machinery.

7. In paragraph 1, The above control unit, When the above-mentioned required driving pattern is determined as a rotation in place, the volume of the left driving motor and the volume of the right driving motor are controlled to have the same value, When the above-mentioned required driving pattern is determined as curved driving, the volume of the driving motor corresponding to the larger one of the Dmd1 and the Dmd2 among the left driving motor and the right driving motor is controlled to be greater than the same value. Work machinery.

8. In paragraph 1, The above working machine, A first inlet valve configured to allow or block the inflow of fluid into the left driving motor; A first discharge valve configured to allow or block the discharge of fluid from the left driving motor; A second inlet valve configured to allow or block the inflow of fluid into the right driving motor; A second discharge valve configured to allow or block the discharge of fluid from the right drive motor, The above control unit, When the actual rotation speed of the left driving motor corresponding to the Dmd1 becomes smaller than the required rotation speed of the left driving motor, the opening amount of the first inlet valve is increased, and when the actual rotation speed of the left driving motor becomes larger than the required rotation speed of the left driving motor corresponding to the Dmd1, the opening amount of the first inlet valve is decreased. When the actual rotation speed of the right driving motor corresponding to the Dmd2 becomes smaller than the required rotation speed of the right driving motor, the opening amount of the second inlet valve is increased, and when the actual rotation speed of the right driving motor corresponding to the Dmd2 becomes larger than the required rotation speed of the right driving motor, the opening amount of the second inlet valve is controlled to be decreased. Work machinery.

9. Left driving motor, Right drive motor; A first operator input device that receives Dmd1, which is an operator's request for the rotation speed of the left driving motor, A second operator input device that receives Dmd2, which is the operator's request for the rotation speed of the right driving motor; A control unit comprising a control unit that determines a required driving pattern based on the Dmd1 and the Dmd2. Work machinery.

10. In paragraph 9, The above required driving pattern includes at least straight driving, The above control unit determines the straight driving when at least Dmd1 ≠ 0, Dmd2 ≠ 0 and Dmd2 = Dmd1. Work machinery.

11. In paragraph 10, The above control unit determines the straight driving when Dmd1 and Dmd2 are Dmd1 ≠ 0 and Dmd2 ≠ 0 and Dmd2 = Dmd1 or is in the adjacent area. Work machinery.

12. In paragraph 11, The above control unit, 0 < Dmd1, 0 < Dmd2, and Dmd1 - a < Dmd2 < Dmd1 + a, or When Dmd1 < 0, Dmd2 < 0, and Dmd1 - a < Dmd2 < Dmd1 + a, Decided to drive straight ahead, Here, a is a positive integer, Work machinery.

13. In paragraph 9, The above required driving pattern includes at least a rotation in place, The above control unit, At least, when Dmd1 ≠ 0 and Dmd2 ≠ 0 and Dmd2 = - Dmd1, determined by the above in-place rotation, Work machinery.

14. In paragraph 13, The above control unit determines the in-place rotation when Dmd1 and Dmd2 are in the adjacent area, or when Dmd1 ≠ 0 and Dmd2 ≠ 0 and Dmd2 = - Dmd1. Work machinery.

15. In paragraph 14, The above control unit, 0 < Dmd1, Dmd2 < 0, - Dmd1 - b < Dmd2 < - Dmd1 + b, or When Dmd1 < 0, 0 < Dmd2, and - Dmd1 - b < Dmd2 < - Dmd1 + b, Determined by the above in-place rotation, Here, b is a positive integer, Work machinery.

16. In paragraph 9, The above required driving pattern includes at least curved driving, The above control unit, 0 < Dmd1, 0 < Dmd2, and Dmd2 < Dmd1 - a, or 0 < Dmd1, 0 < Dmd2, and Dmd1 + a < Dmd2, or 0 < Dmd1, Dmd2 < 0, - Dmd1 + b < Dmd2, or 0 < Dmd1, Dmd2 < 0, Dmd2 < - Dmd1 - b, or Dmd1 < 0, Dmd2 < 0, and Dmd1 + a < Dmd2, or Dmd1 < 0, Dmd2 < 0, Dmd2 < Dmd1 - a, or Dmd1 < 0, 0 < Dmd2, - Dmd1 + b < Dmd2, or When Dmd1 < 0, 0 < Dmd2, and Dmd2 < - Dmd1 - b, Determined by the above curve driving, Here, a and b are positive integers, Work machinery.

17. In paragraph 16, a < b, Work machinery.

18. In paragraph 9, The first operator input device and the second operator input device are hydraulic or electric driving levers or driving pedals, and the magnitude of the pressure of the hydraulic signal or the magnitude of the current of the electric signal, which varies according to the amount of operation of the driving levers or the driving pedals, are input to the Dmd1 and the Dmd2. Work machinery.

19. In paragraph 1 or paragraph 9, High pressure side, Low pressure side, A first inlet valve configured to allow or block fluid communication between the high pressure side and the inlet side of the left driving motor; A first outlet valve configured to allow or block fluid communication between the outlet side of the left driving motor and the low pressure side; A second inlet valve configured to allow or block fluid communication between the high pressure side and the inlet side of the right driving motor; A second outlet valve configured to allow or block fluid communication between the outlet side of the right drive motor and the low pressure side, Work machinery.

20. In paragraph 19, The high pressure side includes at least one high pressure accumulator, The above low pressure side includes at least one low pressure accumulator, Work machinery.

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