Mobile working machine, and method for controlling a safety function of the mobile working machine
Patent Information
- Application Number
- EP2023847743
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-12-19
- Filing Date
- 2023-11-20
- Publication Date
- 2025-10-29
AI Technical Summary
Mobile work machines, such as tractors and wheel loaders, are prone to collisions with obstacles due to limited visibility and low-speed operations, which can result in damage and injury, and existing driving assistance systems are not effectively adapted for these vehicles.
A mobile work machine equipped with an electronically controllable brake system, an apron monitoring device with a distance sensor, and a front load monitoring device with a positioning position sensor, allowing for the detection of obstacles and initiation of emergency braking to prevent collisions.
The system effectively prevents collisions by issuing warnings and initiating emergency braking when obstacles are detected, ensuring the safety of both the machine and its operators by adapting to the work machine's specific operational conditions.
Smart Images
Figure 1.1
Abstract
Description
[0001] Mobile work machine and method for controlling a safety function of the mobile work machine
[0002] Description
[0003] The invention relates to a mobile, i.e., self-propelled, work machine with a front loading device having a raising and lowering loading device, a hydraulic or pneumatic braking system having at least one electronically controllable brake circuit, and a central control unit by means of which the brake circuit can be at least indirectly controlled and a safety function of the work machine can be operated. Furthermore, the invention relates to a method for controlling such a safety function of such a work machine, with which a collision with an obstacle located in front of the work machine can be avoided.
[0004] Mobile work machines, such as tractors, wheel loaders, forklifts, and telehandlers, are often equipped with a front loading device, depending on their design. This device has a lifting and lowering loading device, such as a loading shovel or loading fork. To pick up the load, the load to be picked up, such as a pile of bulk material or a pallet with objects stacked on it, is carefully approached at a low forward speed with the loading device lowered, making contact. To unload the picked-up load, the load is first reversed away from the pick-up location with the loading device raised, and then moved forward to the unloading location, such as the loading area of a truck or trailer, or the loading floor of a storage rack.This can lead to an unintentional collision of the work machine, in particular its loading device, with an obstacle such as a truck, a trailer or the load rack, partly due to poor visibility for the driver when the loading device is raised. It is also possible for a person in the unloading area to be accidentally hit. Such a collision can damage the work machine and equipment, as well as injure people, and should therefore be avoided. Driver assistance systems for motor vehicles primarily intended for road traffic, as well as methods for controlling them, are already known. These systems, in which internal and external data about the vehicle's surroundings are at least partially recorded and evaluated by sensors.If the evaluation of this data indicates a risk of collision with an obstacle in front of the vehicle, an emergency braking of the vehicle is initiated and carried out.
[0005] For example, DE 102014 004 110 A1 describes a method for operating an autonomous driving safety or driver assistance system of a motor vehicle that can function as an emergency braking system. When using an emergency braking function, emergency braking is initiated and executed if the evaluation of at least partially sensor-determined internal and external vehicle data indicates an imminent collision with a vehicle ahead or a stationary obstacle.
[0006] DE 102017 100 980 A1 discloses a method for automatically executing an emergency braking maneuver in a motor vehicle, in which internal and external vehicle parameters are determined and evaluated. The method provides for an emergency braking maneuver to be performed if a dangerous situation is detected based on the evaluation of the internal and external vehicle parameters.
[0007] Against this background, the invention is based on the object of presenting a mobile work machine of the type mentioned above, which has a device for avoiding a collision with an obstacle located in front of the work machine. Furthermore, a method for controlling a safety function of such a work machine is to be specified, with which a collision with an obstacle located in front of the work machine can be avoided.
[0008] The solution to these problems is defined in the independent claims. Advantageous embodiments and further developments are defined in the respective dependent claims. Accordingly, the invention initially relates to a work machine with a front loading device having a raising and lowering loading device, a hydraulic or pneumatic braking system having at least one electronically controllable brake circuit, and a central control unit by means of which the brake circuit can be at least indirectly controlled and a safety function of the work machine can be operated.
[0009] To achieve the task of the device, it is intended that the following components are also present and connected to the central control unit via signal technology to carry out the safety function and thus to avoid a collision with an obstacle in front of the working machine:
[0010] - an apron monitoring device with at least one distance sensor arranged at the front of the working machine for determining the distance of the working machine to an obstacle in front of the working machine, and
[0011] - a front load monitoring device with a position sensor arranged on the front loading device to determine the current position of the loading device.
[0012] The invention is therefore based on a mobile, i.e., self-propelled work machine, such as a tractor, a wheel loader, a forklift, or a telehandler, which has a front loading device with a raising and lowering loading device, such as a loading shovel or a loading fork, as well as a hydraulic or pneumatic braking system with at least one electronically controllable brake circuit. Furthermore, a central control unit is provided, by means of which the brake circuit can be at least indirectly controlled and a safety function of the work machine can be operated.
[0013] The electronically controllable brake circuit of the braking system provides the safety function of electronically triggering an emergency brake. The distance sensor of the apron monitoring system can determine the distance to an obstacle in front of the machine, allowing an acoustic or visual warning signal to be issued and / or emergency braking to be initiated and carried out if the current distance to the obstacle has reached or fallen below a critical distance. The position sensor of the front load monitoring system can determine the current position of the loading device and thus determine whether the loading device is within or outside the detection range of the distance sensor.Depending on the result of the detection, a decision can then be made as to whether the relevant safety function is activated or deactivated to avoid a collision with an obstacle in front of the working machine.
[0014] Since the driving speed of mobile work machines is relatively low and the distances to other vehicles and stationary obstacles in the working environment of mobile work machines are comparatively small, the distance sensor of the apron monitoring system is preferably designed as an ultrasonic sensor. The distance sensor is connected to the electronic control unit via an electrical sensor cable. However, other distance sensor designs are also possible, such as an infrared sensor, laser sensor, or imaging sensor.
[0015] The setting position sensor of the front load monitoring device can be designed as a rotation angle sensor, which is arranged on a suitable joint of the front loading device and is connected to the electronic control unit via an electrical sensor line.
[0016] Alternatively, or additionally for redundancy, the setting position sensor of the front load monitoring device can also be designed as a pressure sensor, which is connected to a suitable setting cylinder of the front loading device and is connected to the electronic control unit via an electrical sensor line.
[0017] If the drive transmission of the off-road vehicle is designed as an electronically controlled CVT transmission, emergency braking can be supported by continuously increasing the transmission ratio. CVT transmissions are typically referred to as belt-driven conical-pulley transmissions whose transmission ratio is continuously variable. If the drive transmission of the off-road vehicle is designed as an electronically controlled multi-step transmission and can be shifted into its neutral position, in which the power transmission between a drive motor and a drive axle is interrupted, emergency braking of the off-road vehicle can also be supported by a corresponding control of the drive transmission due to the loss of drive power from the drive motor.
[0018] If an electronically controllable separating clutch is arranged in the drive train of the working machine and the power transmission between the drive motor and the drive axle can be interrupted by disengaging the separating clutch, emergency braking of the working machine can also be supported by appropriate control of the separating clutch.
[0019] As mentioned at the outset, the invention also relates to a method for controlling a safety function of a mobile work machine, which has a front loading device with a lifting and lowering loading device, which has a hydraulic or pneumatic braking system with at least one electronically controllable braking circuit, and which has a central control unit by means of which the braking circuit can be controlled at least indirectly and a safety function of the work machine can be operated.
[0020] To achieve the object relating to the method, it is provided that the distance of the work machine to an obstacle located in front of the work machine is determined by means of at least one distance sensor of an apron monitoring device arranged on the front of the vehicle of the work machine, and that a warning signal is emitted and / or an emergency braking is carried out depending on the size of the determined distance.
[0021] This method for controlling a safety function of a mobile work machine is intended to prevent a collision with an obstacle located in front of the work machine. It requires that the mobile work machine be equipped with a front loader with a raising and lowering loading device, as well as a hydraulic or pneumatic braking system with at least one electronically controllable brake circuit. By using sensors to determine the distance of the work machine from an obstacle located in front of the work machine, a warning signal can be issued when the distance to the obstacle is reached or undershot, and / or emergency braking can be initiated and executed when the distance to the obstacle is reached or undershot.
[0022] In order to avoid obstruction of the distance sensor and resulting malfunction of the safety function, according to a further development of the method, the current position of the loading device is determined by means of a position sensor of a front load monitoring device arranged on the front loading device, and the safety function is activated or deactivated depending on whether the loading device is outside or within a detection range of the distance sensor.
[0023] For this purpose, the charging device's positioning range is divided into an upper positioning range, in which the charging device is outside the detection range of the distance sensor, and a lower positioning range, in which the charging device is within the detection range of the distance sensor. The safety function is activated when the charging device's current positioning position is within the upper positioning range and deactivated when the charging device's current positioning position is within the lower positioning range. This largely eliminates any interference with the distance sensor and the resulting malfunction of the safety function.
[0024] Since the safety function is limited to monitoring the area in front of the construction machine, a further embodiment of the method can provide for the current direction of travel of the work machine to be determined by means of at least one acceleration sensor and / or at least one wheel speed sensor, and for the safety function to be activated when the work machine is moving forward and deactivated when the work machine is moving backward or at a standstill. To warn the driver of the work machine of a possible collision with an obstacle and the possible triggering of an emergency braking maneuver, it can also be provided for an acoustic and / or visual warning signal to be emitted, for example in the driver's cab of the work machine, when the determined distance has reached or fallen below a predetermined, larger first distance limit value.
[0025] By appropriately controlling the electronically controllable brake circuit of the braking system, emergency braking is preferably triggered when the detected distance has reached or fallen below a predefined lower second distance limit value.
[0026] Since the braking distance of a vehicle increases quadratically with the driving speed, several distance limit values are preferably provided for different forward driving speeds, with the distance limit values increasing quadratically with the forward driving speed.
[0027] Alternatively, the specified distance limits can also be multiplied by a speed-dependent correction factor K, which increases quadratically with the forward driving speed.
[0028] According to another refinement of the method, a braking value signal output to an electronic brake control unit for emergency braking is advantageously determined variably depending on the forward driving speed, with the braking value signal increasing with increasing forward driving speed. A quadratic increase in the output braking value signal is not absolutely necessary, since emergency braking is initiated earlier at higher forward driving speeds, i.e., at a greater distance from the obstacle.
[0029] To support emergency braking of the work machine, if a trailer is coupled to the work machine and the emergency braking is triggered, an electronically controllable trailer control valve of the work machine should be activated in such a way that the trailer is also braked.
[0030] An emergency braking of the work machine can also be supported by an electronically controllable drive motor of the work machine being activated in such a way that it operates in overrun mode when an emergency braking is triggered, or by the gear ratio of a drive transmission of the work machine designed as an electronically controllable CVT transmission being continuously and continuously increased when an emergency braking is triggered, or by a drive transmission of the work machine designed as an electronically controllable stepless transmission being switched to its neutral position when an emergency braking is triggered, in which the power transmission between a drive motor and the at least one drive axle is interrupted, or by an electronically controllable separating clutch arranged in the drive train of the work machine being disengaged when an emergency braking is triggered in order to interrupt the power transmission between the drive motor and the drive axle.
[0031] The invention will be explained in more detail below with reference to an embodiment shown in the accompanying drawing.
[0032] Fig. 1 a mobile work machine with a front loading device in a first working position,
[0033] Fig. 2 the working machine according to Fig. 1 in a second working position, and
[0034] Fig. 3 shows a braking system of a mobile work machine in a schematic illustration.
[0035] The mobile work machine 2 depicted in Figures 1 and 2 is designed as a wheel loader and has a vehicle frame 6 on which a front axle 24 and a rear axle 28 are suspended. The rear axle 28 forms the drive axle of the work machine 2. A front loading device 4 with a raisable and lowerable loading device 12, which is designed as a loading shovel, is arranged at the front of the wheel loader 2. The front loading device 4 has a support arm 10, which is pivotally mounted on the vehicle frame 6 of the wheel loader 2 via a joint 8 and can be pivoted up and down via a hydraulic actuating cylinder 14.
[0036] The wheel loader 2 has a hydraulic braking system 22 with an electronically controllable braking circuit, which is schematically illustrated in Fig. 3 and whose structure and operation are explained below. In addition, the wheel loader 2 has an apron monitoring device 122 with at least one distance sensor 124 arranged on the front of the work machine 2 for determining the distance to an obstacle 18, 18* located in front of the work machine 2, and a front load monitoring device 128 with a setting position sensor 130 arranged on the front loading device 4 for determining the current setting position of the loading device 12, here the loading shovel 12. The setting position sensor 130 can be designed as a rotation angle sensor, which is arranged on the joint 6 of the front loading device 4 and is connected to a central electronic control unit 60 of the work machine 2 via an electrical sensor line 132.Alternatively, the setting position sensor 130 can also be designed as a pressure sensor which is connected to the setting cylinder 14 of the front loading device 4 and is connected to the central control unit 60 via an electrical sensor line 132.
[0037] A safety function for preventing a collision of the work machine 2 with an obstacle 18, 18* located in front of the work machine 2 provides that the distance to an obstacle 18, 18* located in front of the work machine 2 is determined by means of the distance sensor 124 of the apron monitoring device 122, and that, depending on the determined distance, a warning signal is issued and / or an emergency braking is triggered and carried out. Furthermore, it is provided that the current position of the loading device 12, here the loading shovel 12, is detected by means of the setting position sensor 130 of the front load monitoring device 128, and that the safety function is activated or deactivated depending on whether the loading device 12 is outside or within the detection range of the distance sensor 124.
[0038] For this purpose, the positioning range B of the charging device 12 is divided into an upper positioning range Bo, in which the charging device 12 is located outside the detection range of the distance sensor 124, and a lower positioning range Bu, in which the charging device 12 is located within the detection range of the distance sensor 124. The safety function is activated when the current positioning position of the charging device 12 is within the upper positioning range Bo and is deactivated when the current positioning position of the charging device 12 is within the lower positioning range Bu.
[0039] In Fig. 1, the work machine 2 is depicted in a first working position, in which the work machine 2, with the lowered loading shovel 12, is ready to drive forward into a pile of bulk material 16, such as sand, gravel, corn, or grain, located in front of the work machine 2 to pick up the load. Since the lowered loading shovel 12 is within the lower adjustment range Bu and thus within the detection range of the distance sensor 124, the safety function is deactivated here.
[0040] In Fig. 2, the work machine 2 is depicted in a second working position, in which the work machine 2, with its loading shovel 12 raised, is ready to unload previously picked-up bulk material 16 onto the loading area 20 of a trailer 18* parked in front of the work machine 2. This trailer 18* represents the aforementioned obstacle 18. Since the raised loading shovel 12 is within the upper adjustment range Bo and thus outside the detection range of the distance sensor 124, the safety function is activated.In order to avoid an undesirable collision of the working machine 2 with the trailer vehicle 18* during further forward travel, the safety function, which is also only activated during forward travel, provides that an acoustic and / or optical warning signal is emitted in the driver's cab of the working machine 2 when the detected distance A of the working machine 2 from the trailer vehicle 18* has reached or fallen below a previously defined larger first distance limit value Ai.
[0041] As the work machine 2 approaches the trailer 18* further, the safety function provides that an emergency braking is triggered and carried out by appropriately controlling the electronically controllable brake circuit 106 of the braking system 22 if the determined distance A has reached or fallen below a predefined, lower second distance limit value A2 (A < A2). The two aforementioned distance limit values Ai, A2 can be variably determined depending on the driving speed VF of the work machine 2 and can be determined to be larger with increasing driving speed VF, in particular increasing quadratically with the driving speed VF (Ai ~ VF 2 , A2 ~ VF 2 ).
[0042] Likewise, a braking value signal output to an electronic brake control unit 40 of the braking system 22 for emergency braking can be variably determined depending on the forward speed VF, with the braking value signal increasing with increasing forward speed VF. If the braking system 22, as shown in Fig. 3, has an electronically controllable trailer control valve 88, emergency braking of a trailer 18* coupled to the work machine 2 can also be supported by a corresponding control of the trailer control valve 88 and thus the braking of the trailer 18*.
[0043] The schematic illustration in Fig. 3 shows a known braking system 22 of a mobile work machine 2, in which the method having the features of the invention can be applied. The work machine 2 has a non-driven front axle 24 with two front wheels 26a, 26b arranged on either side, and a rear axle 28 designed as a drive axle with two rear wheels 30a, 30b arranged on either side. A wheel speed sensor 32a, 32b, 36a, 36b is arranged on each of the wheels 26a, 26b, 30a, 30b of the two vehicle axles 24, 26, which are connected to the aforementioned electronic brake control unit 40 via sensor lines 34a, 34b, 38a, 38b. The brake control unit 40 can determine the direction of travel and the driving speed VF of the working machine 2 from the sensor signals of the wheel speed sensors 32a, 32b, 36a, 35b.
[0044] The braking system 22 has a hydraulic primary braking system 72 and a hydraulic secondary braking system 106, as well as the aforementioned pneumatic trailer control valve 88. A hydraulic pressure medium source 42 comprises an oil pump 46, from which hydraulic oil can be pumped from a hydraulic reservoir 44 via a relay valve 48 into a hydraulic pressure medium treatment device 50. In the pressure medium treatment device 50, the pumped hydraulic oil is cleaned, cooled, and fed into two supply lines 52, 62. A hydraulic pressure sensor 54, 64 and a hydraulic pressure accumulator 58, 68 are connected to each of these two supply lines 52, 62. The two pressure sensors 54, 64 are connected to the central electronic control unit 60 of the work machine 2 via electrical sensor lines 56, 66.Also connected to this control unit 60 is an operating element 70 designed as a direction of travel lever, via which the direction of travel of the work vehicle 2, i.e. forward and reverse, can be selected.
[0045] The primary brake system 72 can be used as a service brake system and as a steering brake system and, in this case, has two brake circuits, each assigned to a side of the vehicle. The primary brake system 72 comprises the first supply line 52 with the associated hydraulic pressure accumulator 58, two foot brake valves 74a, 74b that can be mechanically actuated by the driver of the work machine 2 via a brake pedal, an axle relay valve 76, and two wheel brake lines 78a, 78b. The two foot brake valves 74a, 74b are connected on the inlet side to the supply line 52 and on the outlet side to the axle relay valve 76. The axle relay valve 76 is also connected to the supply line 52. The two wheel brake lines 78a, 78b are each routed from the axle relay valve 76 to a wheel brake cylinder 80a, 80b. The two wheel brake cylinders 80a, 80b are designed as actively acting diaphragm or piston brake cylinders and are arranged on the wheel brakes of the rear wheels 30a, 30b.
[0046] When functioning as a service brake system, the brake pedals of the foot brake valves 74a, 74b are mechanically coupled to one another, so that when one of the two brake pedals is actuated, both wheel brake cylinders 80a, 80b are synchronously subjected to the same brake pressure, thereby braking the work vehicle 2 in a directional manner. When functioning as a steering brake system, the brake pedals are mechanically separated, so that when one of the two brake pedals is actuated, only the associated wheel brake cylinder 80a; 80b is actuated with brake pressure, thereby assisting a cornering or turning maneuver of the work vehicle 2 in the respective direction. A travel sensor 82a, 82b arranged on each of the two foot brake valves 74a, 74b detects the travel of the respective valve piston and transmits this information via an electrical sensor line 84a, 84b to the central control unit 60, in which a brake value signal can be generated from the respective travel signal.The central control unit 60 is connected to the brake control unit 40 via a data bus 86, such as a CAN bus.
[0047] The trailer control valve 88 is connected on the inlet side via a third supply line 92 to a compressed air source 90 and via a brake control line 94 to the axle relay valve 76 of the primary brake system 72. In addition, the trailer control valve 88 is connected to the brake control unit 40 via an electrical control line 96 and can thus also be controlled electronically. During normal operation, the pneumatic supply pressure present on the inlet side is reduced as needed and passed through the trailer control valve 88 and on the outlet side via a fourth supply line 98 to a "supply" coupling head (red) 100. In addition, a brake control pressure is set in the trailer control valve 88 depending on the brake pressure present in the brake control line 94 and / or a control signal transmitted via the control line 96, which brake control pressure is passed via a brake control line 102 to a "brake" coupling head (yellow) 104.When a trailer is coupled, its compressed air-operated braking system is supplied with the supply pressure applied to the “supply” coupling head 100 and is controlled as a function of the brake control pressure applied to the “brake” coupling head 104.
[0048] The secondary brake system 106 is designed to be electronically controllable and can be used at least as an auxiliary brake system, in whose function the work vehicle 2 can be safely braked in the event of a failure of the primary brake system 72. The secondary brake system 106 has only one brake circuit and includes the second supply line 62 with the associated hydraulic pressure accumulator 68, a brake control valve 108, an axle brake line 110 branching into two wheel brake lines 112a, 112b, and two wheel brake cylinders 114a, 114b, each connected to one of the wheel brake lines 112a, 112b. The two wheel brake cylinders 114a, 114b are designed as actively acting diaphragm or piston brake cylinders and are arranged on the wheel brakes of the front wheels 26a, 26b.The brake control valve 108 is designed as a 3 / 3-way proportional solenoid valve with a pressure medium inlet, a pressure medium outlet, and a working port. The working port is continuously adjustable between a connection to the pressure medium outlet and the pressure medium inlet. The pressure medium inlet is connected to the hydraulic pressure medium source 42 via the second supply line 62, the pressure medium outlet is connected to a pressureless hydraulic reservoir, and the working port is connected to the wheel brake cylinders 114a, 114b via the axle brake line 110.By means of a corresponding control of the brake control valve 108, the brake pressure acting in the axle brake line 110 and in the wheel brake cylinders 114a, 114b connected to this axle brake line 110 can be continuously adjusted between a minimum pressure corresponding to the ambient pressure and a maximum pressure corresponding to the supply pressure present in the supply line 62.
[0049] The electromagnet of the brake control valve 108 can be controlled directly by the brake control unit 40 via a two-wire electrical control line 116. The working connection of the brake control valve 108 is connected to the pressure fluid outlet in the de-energized state and, in the fully energized state, to the pressure fluid inlet without any restriction. To determine and monitor the brake pressure introduced into the axle brake line 110 via the brake control valve 108, an electrohydraulic pressure sensor 118 is connected to the axle brake line 110. This pressure sensor is connected to the brake control unit 40 via an electrical sensor line 120. The secondary brake system 106 is thus purely electronically controllable.The brake pressure in the axle brake line 110 and in the wheel brake cylinders 114a, 114b connected to this axle brake line 110 can thus be adjusted independently of the primary brake system 72 as a function of a brake value signal, which can be determined in the brake control unit 40 from the sensor signals of the travel sensors 82a, 82b or in another way.
[0050] To implement the safety function, Fig. 3 also shows two distance sensors 124a, 124b of the apron monitoring device 122, preferably designed as ultrasonic sensors, and a setting position sensor 130 of the front load monitoring device 128. The two distance sensors 124a, 124b are arranged laterally offset on the front of the work machine 2 and connected to the central control unit 60 via electrical sensor lines 126a, 126b. The setting position sensor 130 is arranged on the front loader device 4, as shown in Figures 1 and 2, and is connected to the central control unit 60 via an electrical sensor line 132.
[0051] List of reference symbols (part of the description)
[0052] Mobile work machine, wheel loader
[0053] Front loading device
[0054] vehicle frame
[0055] joint
[0056] Support arm
[0057] Loading device, loading shovel
[0058] Actuating cylinder
[0059] Bulk goods
[0060] Obstacle * Trailer vehicle, obstacle
[0061] loading area
[0062] braking system
[0063] Front axle a First front wheel b Second front wheel
[0064] Rear axle, drive axle a First rear wheel b Second rear wheel a First wheel speed sensor b Second wheel speed sensor a First sensor line b Second sensor line a Third wheel speed sensor b Fourth wheel speed sensor a Third sensor line b Fourth sensor line
[0065] brake control unit
[0066] Hydraulic pressure medium source
[0067] Oil pump collection tank
[0068] Relay valve
[0069] Pressure medium treatment device
[0070] First supply line
[0071] First pressure sensor
[0072] Fifth sensor line
[0073] First pressure accumulator
[0074] Central control unit
[0075] Second supply line
[0076] Second pressure sensor
[0077] Sixth sensor line
[0078] Second pressure accumulator
[0079] Control element, direction lever
[0080] Primary brake system a First foot brake valve b Second foot brake valve
[0081] Axle relay valve a First wheel brake line b Second wheel brake line a First wheel brake cylinder b Second wheel brake cylinder a First travel sensor b Second travel sensor a Seventh sensor line b Eighth sensor line
[0082] Data bus, CAN bus
[0083] Trailer control valve
[0084] Compressed air source
[0085] Third supply line
[0086] First brake control line
[0087] First control line
[0088] Fourth supply line 100 coupling head “supply” (red)
[0089] 102 Second brake control line
[0090] 104 Coupling head “Brake” (yellow)
[0091] 106 Secondary brake system, brake circuit
[0092] 108 Brake control valve
[0093] 110 axle brake line
[0094] 112a Third wheel brake line
[0095] 112b Fourth wheel brake line
[0096] 114a Third wheel brake cylinder
[0097] 114b Fourth wheel brake cylinder
[0098] 116 Second control line
[0099] 118 Third pressure sensor
[0100] 120 Ninth sensor line
[0101] 122 apron surveillance facility
[0102] 124 First distance sensor, ultrasonic sensor
[0103] 124a Second distance sensor, ultrasonic sensor
[0104] 124b Third distance sensor, ultrasonic sensor
[0105] 126a Tenth sensor line
[0106] 126b Eleventh sensor line
[0107] 128 Front load monitoring device
[0108] 130 Position sensor, angle sensor or pressure sensor
[0109] 132 Twelfth sensor line
[0110] A Detected distance
[0111] Ai First distance limit
[0112] A2 Second distance limit
[0113] B Adjustment range, swivel range
[0114] Bo Upper adjustment range, upper swivel range
[0115] Bu Lower adjustment range, lower swivel range
[0116] K Correction factor
[0117] VF Travel speed, forward travel speed
Claims
Patent claims 1. A mobile work machine (2) comprising a front loading device (4) having a lifting and lowering loading device (12), a hydraulic or pneumatic braking system (22) having at least one electronically controllable braking circuit (106), and a central control unit (60) by means of which the braking circuit (106) can be controlled at least indirectly and a safety function of the work machine (2) can be operated, characterized in that, in order to carry out the safety function and thus to avoid a collision with an obstacle (18, 18*) located in front of the work machine (2), the following components are also present and are connected to the central control unit (60) by means of signals: - an apron monitoring device (122) with at least one distance sensor (124, 124a, 124b) arranged on the front of the working machine (2) for determining the distance (A) of the working machine (2) to an obstacle (18, 18*) located in front of the working machine (2), and - a front load monitoring device (128) with a setting position sensor (130) arranged on the front loading device (4) for determining the current setting position of the loading device (12).
2. Mobile work machine according to claim 1, characterized in that the at least one distance sensor (124, 124a, 124b) of the apron monitoring device (122) is designed as an ultrasonic sensor and is connected to an electronic control unit (60) via an electrical sensor line (126a, 126b).
3. Mobile work machine according to claim 1 or 2, characterized in that the setting position sensor (130) of the front load monitoring device (128) is designed as a rotation angle sensor, is arranged on a suitable joint (8) of the front loading device (4), and is connected to the electronic control unit (60) via an electrical sensor line (132).
4. Mobile work machine according to one of claims 1 to 3, characterized in that the setting position sensor (130) of the front load monitoring device (128) is designed as a pressure sensor, is connected to a setting cylinder (14) of the front loading device (4), and is connected to the electronic control unit (60) via an electrical sensor line (132).
5. Mobile work machine according to one of claims 1 to 4, characterized in that the drive transmission of the work machine (2) is designed as an electronically controllable CVT transmission, the ratio of which is continuously variable.
6. Mobile work machine according to one of claims 1 to 4, characterized in that the drive transmission of the work machine (2) is designed as an electronically controllable step-change transmission, and in that the drive transmission can be switched into a neutral position in which the power transmission between a drive motor of the work machine (2) and at least one drive axle (28) of the work machine (2) is interrupted.
7. Mobile work machine according to one of claims 1 to 6, characterized in that an electronically controllable separating clutch is arranged in the drive train of the work machine (2), and that the power transmission between the drive motor and the at least one drive axle (28) can be interrupted by disengaging the separating clutch.
8. Method for controlling a safety function of a mobile work machine (2), which has a front loading device (4) with a lifting and lowering loading device (12), which has a hydraulic or pneumatic braking system (22) with at least one electronically controllable braking circuit (106), and which has a central control unit (60) by means of which the braking circuit (106) can be controlled at least indirectly and a safety function of the work machine (2) can be operated, characterized in that by means of at least one distance sensor (124, 124a, 124b) of an apron monitoring device (122) arranged on the vehicle front of the work machine (2), the distance (A) of the work machine (2) to a working machine (2) is determined, and that depending on the determined distance (A) a warning signal is issued and / or an emergency braking is carried out.
9. The method according to claim 8, characterized in that the current position of the loading device (12) is determined by means of a setting position sensor (130) of a front load monitoring device (128) arranged on the front loading device (4), and in that the safety function is activated or deactivated depending on whether the loading device (12) is outside or within a detection range of the distance sensor (130).
10. The method according to claim 9, characterized in that the setting range (B) of the charging device (12) is divided into an upper setting range (Bo), in which the charging device (12) is located outside the detection range of the distance sensor (130), and a lower setting range (Bu), in which the charging device (12) is located within the detection range of the distance sensor (130), and in that the safety function is activated when the current setting position of the charging device (12) is within the upper setting range (Bo), and is deactivated when the current setting position of the charging device (12) is within the lower setting range (Bu).
11. Method according to one of claims 8 to 10, characterized in that the current direction of travel of the work machine (2) is determined by means of at least one acceleration sensor and / or by means of at least one wheel speed sensor (32a, 32b, 36a, 35b), and in that the safety function is activated when the work machine (2) is traveling forwards and is deactivated when the work machine is traveling backwards or at a standstill.
12. Method according to one of claims 8 to 11, characterized in that an acoustic and / or optical warning signal is emitted when the determined distance (A) has reached or fallen below a previously defined larger first distance limit value (Ai).
13. Method according to one of claims 8 to 12, characterized in that an emergency braking is triggered by actuating the electronically controllable braking circuit (106) of the braking system (22) when the determined distance (A) has reached or fallen below a previously defined lower second distance limit value (A2).
14. Method according to claim 12 and 13, characterized in that a plurality of distance limit values (Ai, A2) are provided for different forward travel speeds (VF), wherein the distance limit values (Ai, A2) increase quadratically with the forward travel speed (VF).
15. Method according to claim 12 and 13, characterized in that the provided distance limit values (Ai, A2) are multiplied by a speed-dependent correction factor (K), wherein the correction factor (K) increases quadratically with the forward speed (VF) (K ~ VF 2 ).
16. Method according to one of claims 13 to 15, characterized in that a braking value signal output to an electronic brake control unit (40) for emergency braking is determined variably as a function of the forward driving speed (VF), the braking value signal increasing with increasing forward driving speed (VF).
17. Method according to one of claims 8 to 16, characterized in that, in the case of a trailer vehicle (23) coupled to the work machine (2), when emergency braking is triggered, an electronically controllable trailer control valve (88) of the work machine (2) is activated in such a way that the trailer vehicle is also braked.
18. Method according to one of claims 8 to 17, characterized in that when emergency braking is triggered, an electronically controllable drive motor of the working machine (2) is controlled in such a way that it operates in overrun mode.
19. Method according to one of claims 8 to 17, characterized in that when emergency braking is triggered, the ratio of a CVT designed as an electronically controllable Gearbox-designed drive gear of the working machine (2) is continuously and steplessly increased.
20. Method according to one of claims 8 to 17, characterized in that when emergency braking is triggered, a drive transmission of the work machine (2) designed as an electronically controllable step-shift transmission is switched to its neutral position, in which the power transmission between a drive motor and at least one drive axle (28) is interrupted.
21. Method according to one of claims 8 to 17, characterized in that when emergency braking is triggered, an electronically controllable separating clutch arranged in the drive train of the working machine (2) is disengaged, whereby the power transmission between the drive motor and the drive axle (28) is interrupted.