Work vehicle operation control system

Abstract

To provide a work vehicle operation control system capable of suppressing wear on crawlers.SOLUTION: A work vehicle operation control system 1 includes a hydraulic pump 30 driven by an engine, left and right hydraulic motors 40, and a hydraulic pump control unit 23 that controls an amount of pressurized oil discharged from the hydraulic pump 30 after the engine is started, and controls a traveling operation of the work vehicle. When one of a right side crawler traveling speed and a left side crawler traveling speed is equal to or lower than a predetermined traveling reference speed and the other of the right side crawler traveling speed and the left side crawler traveling speed is equal to or higher than the predetermined traveling reference speed, the hydraulic pump control unit 23 controls an amount of pressurized oil discharged from the hydraulic pump 30 so as to decelerate the other crawler traveling speed.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a work vehicle operation control system. [Background technology]

[0002] Some work vehicles such as construction machines use a hydrostatic transmission (HST) that has a hydraulic pump and a hydraulic motor to drive the work vehicle (see the following patent documents). Work vehicles using an HST control the operation of the vehicle (travel, turning, etc.) according to the driving situation.

[0003] In a work vehicle such as a construction machine, when the vehicle runs into soil or rocks while moving forward, or when the crawler gets stuck in sand, mud, slush, etc., the resulting sudden load fluctuation and the inertial force of the vehicle can cause slippage (crawler slippage). When slippage occurs, the rotation speed of the traveling hydraulic motor is reduced while the engine rotation speed is kept constant. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-38002 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, because the rotation speed of the traveling hydraulic motor is controlled after slippage is detected, for example, when the crawler becomes stuck in earth and sand while the work vehicle is traveling and slips, the operator (worker) may increase or decrease the amount of operation of a remote control lever for controlling the traveling hydraulic motor to increase or decrease the rotation speed of the traveling hydraulic motor in order to release the slippage. This operation of the remote control lever by the operator causes wear on the crawler, which has been an issue.

[0006] The present invention has been made in consideration of these problems, and has an object to provide a working vehicle operation control system that can reduce wear on the crawlers. [Means for solving the problem]

[0007] [1] The working vehicle operation control system of this embodiment has a hydraulic pump driven by an engine, left and right hydraulic motors that drive left and right crawlers independently with pressure oil discharged from the hydraulic pump, and a hydraulic pump control unit that controls the amount of pressure oil discharged from the hydraulic pump after the engine is started, and controls the traveling operation of the working vehicle. When one of the right crawler traveling speed and the left crawler traveling speed of the crawlers is equal to or lower than a predetermined traveling reference speed and the other of the right crawler traveling speed and the left crawler traveling speed is equal to or higher than the predetermined traveling reference speed, the hydraulic pump control unit controls the amount of pressure oil discharged from the hydraulic pump so as to decelerate the other crawler traveling speed. Therefore, when one of the left crawler and the right crawler slips, wear of the slipping crawler can be suppressed. [2] In the working vehicle operation control system of this embodiment, it is preferable that the hydraulic pump control unit controls the hydraulic oil discharge amount of the hydraulic pump so as to decelerate the left crawler traveling speed when the right crawler traveling speed of the crawler is equal to or lower than a predetermined right side traveling reference speed and the left crawler traveling speed is equal to or higher than a left side traveling reference speed that is higher than the right side traveling reference speed. This makes it possible to suppress wear on the left crawler when the left crawler slips.

[0008] [3] In the working vehicle operation control system of this embodiment, it is preferable that the hydraulic pump control unit controls the hydraulic oil discharge amount of the hydraulic pump to decelerate the right crawler travel speed when the left crawler travel speed of the crawler is equal to or lower than a predetermined left side travel reference speed and the right crawler travel speed is equal to or higher than a right side travel reference speed that is higher than the left side travel reference speed. This makes it possible to suppress wear on the right crawler when the right crawler slips.

[0009] [4] In the work vehicle operation control system of this embodiment, it is preferable that the system has a display unit with an information input function, and the hydraulic pump control unit determines via the display unit whether or not the driving operation restriction function has been selected and whether or not the operating lever has been operated at least forward by a predetermined tilt amount or more, and when it is determined that the driving operation restriction function has been selected and that the operating lever has been operated forward by at least the predetermined tilt amount, controls the pressurized oil discharge amount of the hydraulic pump so as to decelerate the driving speed of the crawler that is subject to the driving operation restriction. Effect of the Invention

[0010] The working vehicle operation control system of the present invention detects the travel speeds of the left and right crawlers of the working vehicle, detects slippage of the crawlers based on the detected travel speeds of the left and right crawlers, and reduces the travel speed of the slipping crawler, thereby suppressing wear of the slipping crawler. [Brief description of the drawings]

[0011] [Figure 1] 1 is a perspective view of a work vehicle on which a work vehicle operation control system according to an embodiment is mounted, as viewed obliquely from the front side. [Diagram 2] 1 is a block diagram showing a configuration of a working vehicle operation control system according to an embodiment. [Diagram 3] FIG. 2 is a block diagram showing a configuration of a hydraulic pump control unit. [Figure 4] 4 is a flowchart for illustrating a working vehicle operation control process by a hydraulic pump control unit. [Diagram 5] 5 is a schematic diagram illustrating the process from when slippage is detected to when the driving operation restriction process is released. Fig. 5(a) shows the state in which the left crawler slips when traveling straight and with full lever operation, Fig. 5(b) shows the state when the driving operation restriction process is released, and Fig. 5(c) shows the state when the driving operation restriction process is released. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] In the following description, when discussing up, down, left, and right, the bottom side of the work vehicle 10 will be referred to as the bottom and the side opposite the bottom as the top, and the left side of the work vehicle 10 when viewed from the rear will be referred to as the left, and the right side will be referred to as the right.

[0013] [Work vehicle configuration] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. A working vehicle motion control system 1 according to the embodiment will be described by taking as an example a crawler-type skid steer loader with a bucket attached to the end of an arm as a working vehicle. FIG. 1 is a perspective view of a working vehicle on which a working vehicle motion control system according to the embodiment is mounted, viewed obliquely from the front side. In addition, the external configuration of a working vehicle 10 according to the embodiment is not the gist of the present invention, so will only be described briefly.

[0014] As shown in FIG. 1, the work vehicle 10 has a traveling device 12, a main body frame 13 on which the traveling device 12 and the like are mounted, and a cabin 25 provided at the center upper part of the main body frame 13. The traveling device 12 has left and right endless tracks (hereinafter referred to as "crawlers") 11a, 11b, a hydraulic pump 30, and a hydraulic motor 40. The work vehicle 10 has the main body frame 13 to which the traveling devices 12 are attached on the left and right, and a cabin 25 provided at the center upper part of the main body frame 13. The cabin 25 is formed in a box shape, and an operator seat 35 is provided inside the cabin 25 on which an operator sits facing the front side of the vehicle. When an operator sits on the operator seat 35 and operates an operating lever, the traveling device 12 is driven in response to the operation of the operating lever to cause the work vehicle 10 to travel.

[0015] The work vehicle 10 is also provided with an engine 20 at a rear position of the cabin 25. The engine 20 is covered by left and right body frames 13. A first ECU (Electronic Control Unit: vehicle ECU) 22 (see FIG. 2) that functions as a control unit that comprehensively controls the operations of the hydraulic pump 30 (see FIG. 2) and the display unit 60, a second ECU 32 (engine ECU) that controls the engine 20, and a battery (not shown) are provided inside the left and right body frames 13. The first ECU 22 is electrically connected to the second ECU 32, the hydraulic pump 30, the display unit 60, and the battery. The second ECU 32 is electrically connected to the engine 20 and the battery.

[0016] The hydraulic pump 30 is driven by the engine 20. The hydraulic motor 40 is composed of a left hydraulic motor 140 and a right hydraulic motor 141, and is rotated by pressure oil (working oil) discharged from the hydraulic pump 30. The pressure oil of the hydraulic pump 30 is supplied to and discharged from the left hydraulic motor 140 and the right hydraulic motor 141, respectively, by a control signal from the hydraulic pump control unit 23 (see FIG. 2). The left crawler 11a is driven by the left hydraulic motor 140, and the right crawler 11b is driven by the right hydraulic motor 141. In other words, the left crawler 11a and the right crawler 11b are driven independently. Note that, although the present embodiment is described assuming the case where there is one hydraulic pump 30, there may be provided two hydraulic pumps in total, one corresponding to the left hydraulic motor and one corresponding to the right hydraulic motor.

[0017] A first speed sensor (rotational speed sensor) 24 and a second speed sensor (rotational speed sensor) 26 (see FIG. 2) are attached to the left and right hydraulic motors 40, respectively, to measure the rotational speed of the hydraulic motor 40. The rotational speeds detected by the first speed sensor 24 and the second speed sensor 26 are transmitted to the first ECU 22. The first ECU 22 determines whether or not to perform a traveling operation control, which will be described later, based on the traveling speed of the crawlers 11a, 11b based on the rotational speeds detected by the first and second speed sensors 24, 26 and traveling mode information from a traveling mode detection unit 28, which will be described later. Specifically, the first and second speed sensors 24, 26 detect the rotational speed of a drive shaft (not shown) that drives left and right driving sprockets (not shown) that constitute the traveling device 12. The driving sprockets are gear-shaped parts that transmit the rotation of the driving sprockets to the crawlers 11a, 11b. The traveling speeds of the left and right crawlers 11a, 11b are calculated based on the detected rotational speeds. It should be noted that the traveling speeds of the left and right crawlers 11a, 11b may be detected by other methods, for example, by using position information from a Global Positioning System (GPS), and are not limited to the above embodiment.

[0018] [Motion control system] Hereinafter, the working vehicle operation control system 1 that performs driving operation control based on the detection results from the first and second speed sensors 24, 26, the driving mode detection unit 28, and the operation lever sensor 27 will be described with reference to Figs. 2 to 5. Fig. 2 is a block diagram showing the configuration of the working vehicle operation control system 1 according to the embodiment. Fig. 3 is a block diagram showing the configuration of the hydraulic pump control unit 23. Fig. 4 is a flow chart for explaining the working vehicle operation control process of the hydraulic pump control unit 23. Fig. 5 is a schematic diagram showing the process from when slippage is detected to when the driving operation restriction process is released. Fig. 5(a) is a diagram showing a state in which the left crawler slips when traveling straight and the lever is fully operated. Fig. 5(b) is a diagram showing a state when the driving operation is restricted. Fig. 5(c) is a diagram showing a state when the driving operation restriction process is released. In Figs. 1 to 5, the same components as those shown in Fig. 1 are assigned the same reference numerals.

[0019] The working vehicle operation control system 1 has a first ECU 22, a first speed sensor 24, a second speed sensor 26, a driving mode detection unit 28, an operation lever sensor 27, and a display unit 60. The first ECU 22 has a hydraulic pump control unit 23. The first ECU 22 is configured with a microcomputer including, for example, a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), an input / output port, and a communication port (not shown). Examples of signals input to the first ECU 22 include drive shaft rotation speed information from the first speed sensor 24 and the second speed sensor 26, and creep state information from the driving mode detection unit 28. Various control signals are output from the first ECU 22 via an output port. Examples of signals output from the first ECU 22 include control signals to a fuel injection valve (not shown) of the engine 20 and a hydraulic pump 30.

[0020] The first speed sensor 24 measures the rotation speed of the right hydraulic motor 40. The second speed sensor 26 measures the rotation speed of the left hydraulic motor 40. The travel mode detection unit 28 detects whether the travel speed of the crawlers 11a, 11b is set to travel in a creep mode, which is a speed slower than the low speed (for example, a travel speed of 1 km / h or less). Specifically, the travel mode detection unit 28 detects information on whether a creep mode instruction has been issued by the operator (whether the vehicle is in the creep mode or not). The information on whether the vehicle is in the creep mode or not is, but is not limited to, on / off information on a creep mode setting instruction icon (mode setting / cancellation button) displayed on the display unit 60.

[0021] The operating lever sensor 27 is an angle sensor provided on an operating lever (not shown: for example, a joystick) that can be tilted forward, backward, left and right, and can be, for example, a potentiometer. The operating lever sensor 27 detects whether the operating direction of the operating lever is within a range (180 degrees) from forward (meaning going straight) to left and right (meaning movement in the left and right direction) and whether the tilt amount exceeds a predetermined tilt amount, based on the lever angle. For example, if the predetermined tilt amount is set to the maximum tilt amount (so-called full lever), when the operating lever is tilted forward to the upper limit, it is detected as going straight and being in the full lever state. Note that the detection method is not limited to this as long as it can detect the above-mentioned movements.

[0022] The display unit 60 is a touch panel monitor, and functions as a user interface that allows information to be input. This touch panel monitor has a display panel and a touch panel. The display panel is a liquid crystal panel or an organic EL (Electro Luminescence) panel, and displays various graphic information, text information, and buttons. The touch panel is provided over the display panel, and may be of the resistive or capacitive type.

[0023] The hydraulic pump control unit 23 includes a main control unit (main controller) 130, a determination unit 131, a calculation unit 132, an input unit 133, an output unit 134, and a storage unit 135. The main control unit 130 receives the determination result from the determination unit 131 and the calculation result from the calculation unit 132, and generates and outputs a control signal for adjusting the amount of pressure oil of the hydraulic pump 30, which is the object of control. The amount of pressure oil is adjusted to control the rotation speed of the drive shaft, and the traveling speed is controlled. The determination unit 131 determines whether or not to limit the discharge amount of the hydraulic pump 30 according to the detection results from, for example, the first speed sensor 24, the second speed sensor 26, the operation lever sensor 27, and the traveling mode detection unit 28, and outputs the determination result. The calculation unit 132 calculates the current traveling speed based on the detection results from the first speed sensor 24 and the second speed sensor 26, and calculates a control amount (for example, the discharge amount of the hydraulic pump) according to the determination result. The input unit 133 receives the detection results from the first speed sensor 24, the second speed sensor 26, and the driving mode detection unit 28, and information from the user via the display unit 60. The output unit 134 outputs a control signal from the main control unit 130 to a control target (such as the hydraulic pump 30). The memory unit 135 stores a right-side running reference speed, a left-side running reference speed, a predetermined tilt amount, and the like, which are reference values ​​(threshold values) for each judgment described later.

[0024] Display unit 60 is provided in front of the driver's seat inside cabin 25 of work vehicle 10. Display unit 60 displays, for example, an icon indicating whether or not the vehicle is in creep mode and an icon indicating whether or not the engine is on, based on a predetermined display control signal from a display control unit (not shown).

[0025] [Method for controlling the operation of a work vehicle] Specific conditions and how the driving operation is controlled will be described below with reference to the flowchart in Fig. 4. When the engine is started (ON) (step S101), in step S102, the determination unit 131 determines whether the current driving mode is the creep mode or not based on the detection result from the driving mode detection unit 28. If it is determined that the current driving mode is not the creep mode, in step S103, the determination unit 131 determines the following determination items (1) and (2).

[0026] (Judgment item) (1) Determine whether the driving operation restriction mode is selected (ON) (2) Determine whether the operating lever is tilted forward by a predetermined amount or more. Here, for the determination item (1), for example, when the driving operation restriction function button displayed on the display unit 60 is selected (ON), it is determined to be valid. The determination as to whether or not the driving operation restriction mode has been selected is not limited to this. For example, it may also be determined to be valid when a selection button capable of turning the driving operation restriction mode ON / OFF is located on a part other than the display unit 60 and is ON.

[0027] Regarding the judgment item (2), if the control lever is tilted forward by a predetermined amount or more, it is judged as valid. The predetermined amount of tilt refers to the amount of tilt of the control lever, and the larger this value is, the higher the control current value output from the first ECU 22 to the hydraulic pump is, and the higher the driving output is. Since it is difficult for a slip state to occur when the output is small, it is preferable that the predetermined amount of tilt of the control lever is set to an amount close to the maximum value. For example, if the control lever is operated forward (meaning going straight) and the predetermined amount of tilt is maximum (meaning full lever), it is judged as valid. If it is determined in step S103 that all of the above determination items (1) and (2) are valid, the process proceeds to step S104.

[0028] In step S104, the determination unit 131 determines the following determination items (3) and (4). (Judgment item) (3) Determine whether the right side travel speed (travel speed of the right crawler 11b) detected by the first speed sensor 24 is equal to or lower than a preset right side travel reference speed (e.g., 1 km / h (very low speed)) and whether the left side travel speed (travel speed of the left crawler 11a) detected by the speed sensor 26 is equal to or higher than a preset left side travel reference speed (e.g., 2 km / h (low speed)) (valid determination is made if the above conditions are met). The above condition is satisfied when, for example, the left crawler 11a slips and the right crawler 11b stops, as shown in FIG. 5(a). (4) Determine whether the left side travel speed (travel speed of the left crawler 11a) detected by the second speed sensor 26 is equal to or lower than a preset left side travel reference speed (e.g., 1 km / h (very low speed)) and whether the right side travel speed (travel speed of the right crawler 11b) detected by the speed sensor 24 is equal to or higher than a preset right side travel reference speed (e.g., 2 km / h (low speed)) (valid determination is made if the above conditions are met). The case where the above condition is satisfied is assumed to be a situation where, for example, the right crawler 11b slips and the left crawler 11a stops.

[0029] If it is determined in step S104 that either one of the above determination items (3) or (4) is valid, the process proceeds to step S105.

[0030] If the above determination item (3) is determined to be valid, the main control unit 130 controls the hydraulic pump 30 to reduce the hydraulic oil discharge rate of the hydraulic pump 30 and set the left side traveling speed to, for example, 1 km / h (step S105: see FIG. 5(b)), thereby reducing the rotation speed of the left hydraulic motor 40. Note that, although the right side traveling reference speed in determination item (3) is set to 1 km / h and the left side traveling reference speed is set to 2 km / h, they are not limited to these numerical values ​​and are appropriately set depending on the usage environment of the work vehicle 10. Also, although the left side traveling reference speed in determination item (4) is set to 1 km / h and the right side traveling reference speed is set to 2 km / h, they are not limited to these numerical values ​​and are appropriately set depending on the usage environment of the work vehicle 10.

[0031] If the above determination item (4) is determined to be valid, the main control unit 130 controls the hydraulic pump 30 to reduce the hydraulic oil discharge rate of the hydraulic pump 30 to set the second right side traveling speed to, for example, 1 km / h (step S105), and reduces the rotation speed of the right hydraulic motor 40. Note that although the second left side traveling reference speed is set to 1 km / h and the second right side traveling reference speed is set to 2 km / h, they are not limited to these numerical values ​​and are appropriately set depending on the usage environment of the work vehicle 10. Also, although an example has been shown in which the second right side traveling speed is controlled to, for example, 1 km / h, they are not limited to these numerical values ​​and are appropriately set.

[0032] After the transition to the driving operation restriction in step S105, an icon indicating that the driving operation restriction function is active is displayed on the display unit 60, and the process returns to step S102. If it is determined in step S102 that the vehicle is in the creep mode, or if it is determined in step S103 or step S104 that the driving operation restriction function is not active, the driving operation restriction function is disabled, and the driving operation restriction is released (see FIG. 5(c)).

[0033] If it is determined in step S102 that at least one of the judgment items (1) and (2) is not valid, the driving operation restriction function is disabled (step 107) and the process ends. This is because in the case of creep mode, since the vehicle is in ultra-low speed mode (slower than the low speed mode), it is not appropriate to enter the driving operation restriction state. If either of the judgment items (3) or (4) is not valid in step S103, the process proceeds to step 107. This is because if either of the judgment items (3) or (4) is not valid, it is not appropriate to enter the driving operation restriction state since the vehicle is not in a situation where one crawler is slipping and the other crawler is stopped.

[0034] According to the working vehicle operation control system 1 of the embodiment, when one of the left crawler traveling speed and the right crawler traveling speed of the crawlers 11a, 11b is equal to or lower than a predetermined traveling reference speed and the other of the left crawler traveling speed and the right crawler traveling speed is equal to or higher than a predetermined traveling reference speed, the pressure oil discharge amount of the hydraulic pump 30 is controlled so as to decelerate the other crawler traveling speed. Therefore, since the traveling speed of the crawler in a slipping state can be reduced to an extremely low speed, wear of the slipping crawler can be suppressed.

[0035] According to the working vehicle motion control system 1 according to the embodiment, when the right crawler traveling speed is equal to or less than the right side traveling reference speed and the left crawler traveling speed is equal to or greater than the left side traveling reference speed which is greater than the right side traveling reference speed, the hydraulic pump 30 pressure oil discharge amount is controlled to decelerate the left crawler traveling speed. Therefore, the traveling speed of the left crawler 11a in a slipping state can be reduced to an extremely low speed, thereby suppressing wear on the left crawler 11a.

[0036] According to the working vehicle operation control system 1 according to the embodiment, when the left crawler traveling speed is equal to or less than the left side traveling reference speed and the right crawler traveling speed is equal to or greater than the right side traveling reference speed which is greater than the left side traveling reference speed, the hydraulic pump pressure oil discharge amount is controlled to decelerate the right crawler traveling speed. Therefore, the traveling speed of the right crawler 11b in a slipping state can be reduced to an extremely low speed, thereby suppressing wear on the right crawler 11b.

[0037] The working vehicle operation control system 1 according to the embodiment detects the travel speeds of the left and right crawlers when the working vehicle is being operated forward at a predetermined tilt amount or more, and determines whether or not either of the left and right crawlers is in a slipping state based on the detected travel speeds of the left and right crawlers. Therefore, when a crawler in a slipping state is identified, the travel speed of the slipping crawler can be reduced to an extremely low speed (1 km / h) until the state of being operated forward at a predetermined tilt amount or more is released. Therefore, it is possible to transition to the travel operation restriction process in a short time, thereby suppressing wear of the slipping crawler.

[0038] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0039] REFERENCE SIGNS LIST 1 work vehicle operation control system, 10 work vehicle (crawler loader), 11a, 11b endless track (crawler), 12 running gear, 13 main body frame, 20 engine, 22 first ECU, 23 hydraulic pump control section, 24 first speed sensor, 25 cabin, 26 second speed sensor, 27 operation lever sensor, 28 driving mode detection section, 30 hydraulic pump, 32 second ECU, 40 hydraulic motor, 60 display section, 140 left hydraulic motor, 141 right hydraulic motor

Claims

1. A working vehicle operation control system for controlling the traveling operation of a working vehicle having a hydraulic pump driven by an engine and left and right hydraulic motors that independently drive left and right crawlers by pressure oil discharged from the hydraulic pump, a hydraulic pump control unit that controls the amount of pressure oil discharged from the hydraulic pump after the engine is started; the hydraulic pump control unit, when one of the right crawler travel speed and the left crawler travel speed of the crawlers is equal to or lower than a predetermined travel reference speed and the other of the right crawler travel speed and the left crawler travel speed is equal to or higher than a predetermined travel reference speed, controls the pressure oil discharge amount of the hydraulic pump so as to decelerate the other crawler travel speed. A work vehicle operation control system comprising:

2. the hydraulic pump control unit controls a pressure oil discharge amount of the hydraulic pump so as to decelerate the left crawler travel speed when a right crawler travel speed of the crawler is equal to or less than a predetermined right crawler travel reference speed and a left crawler travel speed of the crawler is equal to or greater than a left crawler travel reference speed that is greater than the right crawler travel reference speed.

2. The working vehicle operation control system according to claim 1 .

3. the hydraulic pump control unit controls a pressure oil discharge amount of the hydraulic pump so as to decelerate the right crawler travel speed when a left crawler travel speed of the crawler is equal to or less than a predetermined left side travel reference speed and a right crawler travel speed is equal to or greater than a right side travel reference speed that is greater than the left side travel reference speed.

2. The working vehicle operation control system according to claim 1 .

4. A display unit having an information input function is provided, the hydraulic pump control unit determines whether or not a travel operation limiting function has been selected via the display unit, and determines whether or not an operation lever has been operated at least forward by a predetermined tilt amount or more, and when it is determined that the travel operation limiting function has been selected and that the operation lever has been operated forward by a predetermined tilt amount or more, controls the pressure oil discharge amount of the hydraulic pump so as to decelerate the travel speed of the crawler that is the subject of travel operation limiting.

2. The working vehicle operation control system according to claim 1 .

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