Construction machinery

Abstract

This invention provides a construction machine that can prevent the vehicle from moving unintentionally when it comes to a stop due to deceleration control based on obstacle detection. [Solution] In a tire roller (construction machine), the controller (control device) performs braking control when the vehicle speed V falls below a predetermined speed Vref (step ST16) during deceleration control, by activating the parking brake device (brake device) (step ST21).

Description

【Technical Field】 【0001】 The present invention relates to construction machinery. 【Background Art】 【0002】 Conventionally, technologies related to construction machinery equipped with a drive device using an HST (Hydraulic Static Transmission), a brake device including a service brake device that applies frictional braking force to wheels, and a parking brake device for parking the vehicle body are known. For example, Patent Document 1 discloses a hydraulic drive vehicle that determines that the vehicle body has stopped when the accelerator operation amount is zero and the swash plate angle of a variable swash plate type hydraulic pump is zero, and operates a mechanical holding brake. That is, in this hydraulic drive vehicle, the holding brake is operated in a state where the vehicle body has stopped running according to the operator's intention. 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 Japanese Patent Application Laid-Open No. 9-295565 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 By the way, in construction machinery, when an obstacle exists in the traveling direction of the vehicle body during traveling, deceleration control may be executed to decelerate the vehicle body by reducing the rotational speed of the internal combustion engine. During the execution of this deceleration control, for example, as the working oil becomes high temperature, a leak of the working oil in the traveling circuit may occur, and as a result, the vehicle body may stop running without the operator's intention. Since that state is a state where the vehicle body can move by an external force or the like although it is in a traveling stop state, there is a risk that the vehicle body may start moving unintentionally by the operator. 【0005】 This invention has been made in view of the above problems, and its objective is to provide a construction machine that can prevent the vehicle from starting to move unintentionally when the vehicle has stopped moving due to vehicle deceleration control based on obstacle detection. [Means for solving the problem] 【0006】 To achieve the above objective, the present invention provides a construction machine comprising: a vehicle body; wheels provided on the vehicle body; a prime mover provided on the vehicle body; a hydraulic pump for travel driven by the prime mover; a hydraulic motor for travel connected in a closed circuit to the hydraulic pump for travel and outputting driving force to the wheels; a brake device for maintaining the vehicle body in a stopped state; a vehicle speed detection device for detecting the vehicle speed; an obstacle detection device for detecting obstacles located around the vehicle body; and a control device that, when the obstacle detection device detects an obstacle within a predetermined distance or less from the vehicle body while the vehicle body is traveling, performs deceleration control to reduce the rotational speed of the prime mover and decelerate the vehicle body, wherein the control device performs stopping brake control to activate the brake device when the vehicle speed detected by the vehicle speed detection device falls below a predetermined speed during the execution of the deceleration control. [Effects of the Invention] 【0007】 According to the construction machine of the present invention, when the vehicle body stops moving due to deceleration control based on obstacle detection, it is possible to restrict the vehicle body from starting to move unintentionally by the operator. [Brief explanation of the drawing] 【0008】 [Figure 1] This is a side view showing a tire roller as a construction machine according to an embodiment. [Figure 2] This is a perspective view showing the operating unit of a tire roller. [Figure 3] This is a system configuration diagram for a tire roller. [Figure 4] This flowchart shows an example of collision damage mitigation control. [Figure 5] This flowchart shows an example of brake control while stopped. [Figure 6] This flowchart shows an example of brake control while stopped. [Modes for carrying out the invention] 【0009】 One embodiment of the present invention will be described below with reference to the drawings. Figure 1 is a side view showing a tire roller 100 as a construction machine according to the embodiment. Figure 2 is a perspective view showing the operating unit 9 provided by the tire roller 100. Figure 3 is a system configuration diagram of the tire roller 100. The tire roller 100 is a compaction machine (construction machine) that performs compaction work in asphalt paving construction by compaction work. The tire roller 100 comprises a body 1, front wheels 3 and rear wheels 4 made of rubber and provided on the body 1 as compaction wheels, a drive unit 5, an operating unit 9, and a controller (control device) 10. 【0010】 The vehicle body 1 houses various devices such as a drive unit 5 and a controller 10 within a steel plate frame. The drive unit 5 includes an engine (prime mover) 11, an HST 13, and a drive shaft 15. The engine 11 is an internal combustion engine that operates when fuel is supplied from a fuel tank (not shown). The drive unit 5 may also include a prime mover other than the engine 11, such as an electric motor. An aftertreatment device 12 (Figure 3) is provided in the middle of the exhaust pipe of the engine 11 (not shown). The aftertreatment device 12 is, for example, a device for collecting particulate matter contained in the engine's exhaust gas, and has, for example, a CSF (Catalyzed Soot Filter) as a filter inside. The aftertreatment device 12 includes a temperature sensor for detecting the temperature of the exhaust pipe upstream of the filter, and a pressure sensor for detecting the differential pressure in the exhaust pipe before and after the filter. 【0011】 HST13 is a closed hydraulic circuit having a hydraulic pump (driving hydraulic pump) 13a, a hydraulic motor (driving hydraulic motor) 13b, and a hydraulic path 13c. HST13 drives the hydraulic motor 13b by circulating the hydraulic fluid from the hydraulic pump 13a to the hydraulic motor 13b via the hydraulic path 13c. The hydraulic pump 13a is a double-tilting hydraulic pump that circulates the hydraulic fluid using the driving force of the engine 11. The hydraulic pump 13a is adjusted by a hydraulically operated tilting cylinder (not shown) to a position corresponding to forward (F), reverse (R), and neutral (N, a neutral state that is neither forward nor reverse) as the direction of travel of the vehicle body 1, thereby adjusting the amount and direction of circulation of hydraulic fluid to the hydraulic motor 13b (the direction in which the hydraulic motor 13b rotates). The hydraulic motor 13b transmits the driving force to the rear wheels 4 as drive wheels via the drive shaft 15. 【0012】 Furthermore, the tire roller 100 is equipped with a braking device to maintain the vehicle body 1 in a stopped state. Specifically, the hydraulic motor 13b is provided with a parking brake device (brake device) 13d. The parking brake device 13d is a disc-type friction brake device that applies braking force to the hydraulic motor 13b to stop its drive when the supply of hydraulic fluid is released. In other words, the parking brake device 13d is configured to apply braking force to the hydraulic motor 13b even when the tire roller 100 is not in operation. The parking brake device 13d can be switched on and off by an operator operating a parking brake switch 26 (Figure 3) provided on the operation panel 25 (Figure 2), for example. In addition, the axle 14 is provided with a service brake device (brake device) 13e. The service brake device 13e is a disc-type friction brake device that applies friction braking force to the axle 14 by supplying hydraulic fluid when an operator presses down on the brake pedal 38. 【0013】 The operation unit 9 is a device for the operator to perform various operations on the tire roller 100, and as shown in Figure 2, it is equipped with a forward / reverse lever 21, a steering wheel 23, an operation panel 25, and the like. The forward / reverse lever 21 is an indicator device that allows the operator to change the direction of rotation of the rear wheels 4 by the HST 13 by operating its set position (indicated direction), and set the direction of travel of the vehicle body 1 to forward, reverse, or neutral. The steering wheel 23 allows the operator to rotate the front wheels 3 around the vertical axis of the vehicle body, and adjust the direction of travel of the vehicle body 1 in the left-right direction (vehicle width direction). The operation panel 25 has a monitor 31 that displays the vehicle body 1's travel speed, fuel level, and other various setting statuses, a speaker 33 that sounds a buzzer, and a lamp 34 that illuminates visible light visible to the operator. In addition, a warning light 35 is provided on the vehicle body 1 as a means of displaying warnings. The warning light 35 is mounted, for example, on the roof 2 and emits visible light of multiple colors, such as red, yellow, green, and blue, towards workers positioned around the vehicle body 1. 【0014】 Furthermore, as shown in Figure 1, an accelerator pedal 37 and a brake pedal 38 are located below the operating unit 9, which is at the operator's feet when they are seated. The operator adjusts the amount of pressure (depression) on the accelerator pedal 37 to accelerate and decelerate the vehicle 1, and adjusts the amount of pressure (depression) on the brake pedal 38 to adjust the braking force of the service brake device 13e. The amount of operation of the accelerator pedal 37 (hereinafter referred to as "accelerator operation amount") is detected by the accelerator operation amount detection sensor 47 (Figure 3) and output to the controller 10. The amount of operation of the brake pedal 38 (hereinafter referred to as "brake operation amount") is detected by the brake operation amount detection sensor 48 (Figure 3) and output to the controller 10. 【0015】 Furthermore, the vehicle body 1 is equipped with a hydraulic oil temperature sensor (hydraulic oil temperature detection device) 41 (Figure 3), a tilt sensor (tilt angle detection device) 42 (Figure 3), an infrared sensor (obstacle detection device) 43, and a rotation sensor (vehicle speed detection device, direction of travel detection device) 45. 【0016】 The hydraulic oil temperature sensor 41 is a sensor that detects the temperature of the hydraulic oil supplied to various hydraulic devices including the HST 13, and is provided at any position within the hydraulic circuit. The inclination sensor 42 detects the inclination angle of the vehicle body 1 with respect to the horizontal direction, that is, the inclination angle of the ground (road surface) on which the vehicle body 1 is grounded. The infrared sensor 43 emits infrared rays in the traveling direction of the vehicle body 1, and detects the presence or absence of an obstacle 50 (FIG. 1) in the traveling direction and the distance L between the vehicle body 1 and the obstacle 50. The infrared sensor 43 includes a front infrared sensor 43a disposed on the front side of the vehicle body 1 and a rear infrared sensor 43b disposed on the rear side of the vehicle body 1. Note that the infrared sensor 43 may be provided on the vehicle body 1 so as to be able to detect obstacles located around the vehicle body 1, not limited to the traveling direction of the vehicle body 1. 【0017】 The rotation sensor 45 is disposed, for example, on the rotation shaft of the front wheel 3, and detects the vehicle speed (rotation speed) based on the rotation speed of the front wheel 3. Further, the rotation sensor 45 can detect the current traveling direction of the vehicle body 1 by detecting the rotation direction of the front wheel 3. Here, "traveling" includes cases where the vehicle body 1 travels in one direction due to inertia, or cases where the vehicle body 1 travels in one direction due to its own weight on a slope or the like. The rotation sensor 45 may be a well-known rotation sensor capable of detecting the rotation speed and rotation direction, such as a rotary encoder. The hydraulic oil temperature sensor 41, the inclination sensor 42, the infrared sensor 43, and the rotation sensor 45 output the detection results to the controller 10. 【0018】 The controller 10 is a control device for performing comprehensive control including the operation control of the drive unit 5, and includes an input / output device, a storage device (ROM: Read Only Memory, RAM: Random Access Memory, non-volatile RAM, etc.), a central processing unit (CPU: Central Processing Unit), and the like. 【0019】 As shown in FIG. 3, the controller 10 receives inputs such as the set position of the forward / backward lever 21, the temperature of the hydraulic oil detected by the hydraulic oil temperature sensor 41, the inclination angle of the road surface detected by the inclination sensor 42, the presence or absence of an obstacle 50 detected by the infrared sensor 43 and the distance L between the vehicle body 1 and the obstacle 50, the vehicle speed and the actual traveling direction detected by the rotation sensor 45, the accelerator operation amount detected by the accelerator operation amount detection sensor 47, the brake operation amount detected by the brake operation amount detection sensor 48, the operation instruction of the parking brake switch 26, and values detected by temperature sensors, pressure sensors, etc. (not shown) included in the post-treatment device 12. 【0020】 Based on the set position of the forward / backward lever 21 and the accelerator operation amount, the controller 10 controls the drive unit 5 so that the driving force required for the vehicle body 1 to travel is output to the rear wheels 4. Further, the controller 10 controls the braking force output from the service brake device 13e based on the brake operation amount. Also, the controller 10 controls the operation and release of the parking brake device 13d according to the operation instruction of the parking brake switch 26. Thereby, a parking state of the vehicle body 1 is formed, and for example, it is possible to prevent the vehicle body 1 from moving due to gravity on a slope or the like. 【0021】 Further, while the engine 11 is driving, the controller 10 executes regeneration control of the post-treatment device 12, for example, at predetermined time intervals. The regeneration control is control for burning particulate matter deposited on the filter of the post-treatment device 12 by raising the temperature of the exhaust gas from the engine 11. Specifically, the controller 10 raises the temperature of the exhaust gas by causing post-injection to be performed on an injector (not shown) of the engine 11. 【0022】 Next, the collision damage reduction control will be described. FIG. 4 is a flowchart showing an example of the collision damage reduction control. The process shown in FIG. 4 is executed by the controller 10 at predetermined repetition times (for example, several msec) during the operation of the tire roller 100. 【0023】 The controller 10 determines whether a predetermined release condition is not satisfied (step ST1). The predetermined release condition includes, for example, the tire roller 100 being in the system-off state, the water spray pump of the water spray device mounted on the tire roller 100 being in operation, and when the tire roller 100 is equipped with a transmission (not shown), the gear position of the vehicle speed being set to a high gear. When the controller 10 determines that the predetermined release condition is satisfied (No in step ST1), it executes this routine from the beginning. When the controller 10 determines that the predetermined release condition is not satisfied (Yes in step ST1), it proceeds to step ST2. 【0024】 The controller 10 determines whether an obstacle 50 is detected within a range of a first predetermined distance L1 or less from the vehicle body 1 by each infrared sensor 43 (step ST2). The range of a first predetermined distance L1 or less is the range on the traveling direction side of the vehicle body 1. When the controller 10 determines that no obstacle is detected (No in step ST2), it executes this routine from the beginning. When the controller 10 determines that an obstacle is detected (Yes in step ST2), it proceeds to step ST3. 【0025】 Next, the controller 10 determines in which range the distance L from the vehicle body 1 to the obstacle 50 is included (step ST3). When the controller 10 determines that the distance L is in a range that is less than or equal to the first predetermined distance L1 and greater than a second predetermined distance (predetermined distance) L2 (<L1), it executes warning control (step ST4). Specifically, the controller 10 causes the vehicle body 1 to give notifications and warnings by, for example, displaying a predetermined notification video on the monitor 31, sounding a buzzer sound from the speaker 33, lighting the lamp 34 in a predetermined lighting mode such as flashing, or lighting the warning lamp 35. 【0026】 Further, when the controller 10 determines that the distance L is within a range where it is less than or equal to the second predetermined distance L2 and greater than the third predetermined distance L3 (< L2), it executes deceleration control (step ST5). Specifically, the controller 10 reduces the discharge pressure of the hydraulic pump 13a by reducing the rotational speed of the engine 11, thereby decelerating the vehicle body 1. 【0027】 Also, when the controller 10 determines that the distance L is within a range less than or equal to the third predetermined distance L3, it executes HST brake control (step ST6). Specifically, regardless of the set position of the forward / backward lever 21, the controller 10 sets the HST 13 to a neutral state, that is, sets the swash plate of the hydraulic pump 13a to a neutral position corresponding to neutral. Thereby, the circulating supply of the hydraulic oil from the hydraulic pump 13a to the hydraulic motor 13b is stopped, and a braking force is applied to the hydraulic motor 13b. After steps ST4, ST5, and ST6 above, the controller 10 executes this routine from the beginning. As a result, depending on the distance L between the vehicle body 1 and the obstacle 50, any one of the warning control, deceleration control, and HST brake control is executed. 【0028】 Here, during the execution of the deceleration control described above, there is a possibility that the vehicle body 1 may stop running regardless of the operator's intention. For example, during the execution of the regeneration control of the aftertreatment device 12, in a situation where the load on the hydraulic equipment mounted on the tire roller 100 increases, the temperature of the hydraulic oil rises and its viscosity decreases. As a result, a leak may occur in the hydraulic pressure supplied to the tilting cylinder that adjusts the tilt angle of the swash plate of the hydraulic pump 13a, causing the swash plate of the hydraulic pump 13a to approach the neutral position, and there is a possibility that the driving force output from the HST 13 may be insufficient. Also, for example, when climbing a slope or when the road surface resistance is large, a shortage of driving force is likely to occur. 【0029】 In this state, although the vehicle body 1 is stopped, it can move due to external forces, etc. Also, the factors that caused the vehicle to stop, such as a decrease in the temperature of the hydraulic fluid, may be resolved. As a result, there is a risk that the vehicle body 1 may start moving unintentionally by the operator. Therefore, in the tire roller 100 of this embodiment, the following braking control during stopping is performed to prevent the vehicle body 1 from moving unintentionally by the operator. Figures 5 and 6 are flowcharts of an example of braking control during stopping. The braking control during stopping shown in Figures 5 and 6 is performed by the controller 10 when the execution of deceleration control begins. 【0030】 The controller 10 sets the value of the timer that will be started in a later process to zero (step ST10). Next, the controller 10 determines whether or not a predetermined release condition for collision damage mitigation control is met (step ST11). If the controller 10 determines that the predetermined release condition for collision damage mitigation control is met (No in step ST11), it terminates this routine as shown in Figure 6. If the controller 10 determines that the predetermined release condition for collision damage mitigation control is not met (Yes in step ST11), it proceeds to step ST12. 【0031】 Next, the controller 10 determines whether a predetermined condition exists (step ST12). The predetermined condition here is a condition in which the vehicle body 1 is likely to stop moving during deceleration control. The predetermined condition is, for example, any of the following: (1) the temperature of the hydraulic fluid detected by the hydraulic fluid temperature sensor 41 is above a predetermined temperature, (2) the inclination angle detected by the inclination sensor 42 during uphill driving is above a predetermined angle, or (3) the regeneration control of the after-processing device 12 is in progress. 【0032】 The predetermined temperature is the temperature at which the hydraulic pump 13a may approach neutral due to hydraulic fluid leakage (for example, around 90°C), and is set in advance based on experiments and analyses. The predetermined angle is the slope angle of the road surface at which the vehicle body 1 may stop moving, for example, when the temperature of the hydraulic fluid is relatively high during deceleration control (for example, around 5 degrees), and is set in advance based on experiments and analyses. 【0033】 Furthermore, during regeneration control of the aftertreatment device 12, the load on an auxiliary pump (not shown) directly connected to the engine 11 is increased. Specifically, the hydraulic fluid circulating between the auxiliary pump and a hydraulic fluid tank (not shown) is routed through a relief valve that allows the flow of hydraulic fluid at a predetermined set pressure. As a result, the load on the auxiliary pump increases compared to when regeneration control is not performed, the load on the engine 11 increases, and the temperature of the exhaust gas rises. And because the hydraulic fluid passes through the relief valve, the temperature of the hydraulic fluid rises more easily, which can lead to a situation where the vehicle body 1 is more likely to stop moving during deceleration control. Therefore, when the controller 10 determines that any of the above situations (1) to (3) is occurring (Yes in step ST12), it proceeds to step ST13. 【0034】 Next, the controller 10 determines whether the forward / reverse lever 21 is set to forward (F) or reverse (R) (step ST13). If the controller 10 determines that the forward / reverse lever 21 is set to forward (F) or reverse (R) (Yes in step ST13), it is considered that the operator intends to continue driving the vehicle 1, and the process proceeds to step ST14. 【0035】 Next, the controller 10 determines whether or not the operator has pressed the brake pedal 38 (step ST14). If the controller 10 determines that the brake pedal 38 has not been pressed (Yes in step ST14), it is assumed that the operator intends to continue driving the vehicle 1, and the process proceeds to step ST15. 【0036】 Next, the controller 10 determines whether or not the operator has pressed the accelerator pedal 37 again (step ST15). Pressing the accelerator pedal 37 again by the operator means, for example, within a predetermined time from the current moment, the operator has released the accelerator pedal 37 and then pressed it again. Whether or not the pedal has been pressed again can be determined based on the amount of accelerator operation. If the controller 10 determines that the operator has not pressed the accelerator pedal 37 again (Yes in step ST15), it proceeds to step ST16. 【0037】 Next, the controller 10 determines, based on the detection result of the rotation sensor 45, whether the vehicle speed V of the vehicle body 1 has become less than or equal to a predetermined speed Vref (the rotation speed of the front wheels 3 has become less than or equal to a predetermined rotation speed) (step ST16). The predetermined speed Vref is the speed at which the vehicle body 1 has come to a complete stop or is nearly at a complete stop (for example, a speed of about 0 km / h to 0.2 km / h). The predetermined speed Vref is set to a speed at which even if the parking brake device 13d is activated (step ST21 described later), the impact on the road surface is extremely small and the impact on the operator is extremely small. When the controller 10 determines that the vehicle body 1 has come to a complete stop (Yes in step ST16), it proceeds to step ST17. 【0038】 Next, as shown in Figure 6, the controller 10 determines whether the timer has not yet started timing (step ST17). If the timer has not yet started (Yes in step ST17), the controller 10 starts timing (step ST18); if the timer has already started (No in step ST17), step ST18 is omitted. Then, the controller 10 determines whether a predetermined time Δt has elapsed since the timer started timing, that is, since the vehicle body 1 stopped moving (step ST19). 【0039】 When the controller 10 determines that a predetermined time Δt has elapsed (Yes in step ST19), it controls the HST13 to form a neutral state regardless of the set position of the forward / reverse lever 21 (step ST20). Then, the controller 10 automatically activates the parking brake device 13d regardless of the operation of the parking brake switch 26 (step ST21). This makes it possible to park the vehicle body 1 and restrict its movement. 【0040】 In response to this, if the controller 10 determines that a predetermined time Δt has not elapsed (No in step ST19), it executes the process from step ST11 onwards in Figure 5 again. Then, if the controller 10 determines that none of the above predetermined conditions are met (No in step ST12), that is, if the hydraulic fluid temperature is below the predetermined temperature, the inclination angle during uphill driving is below the predetermined angle, and the after-treatment device 12 is not in regeneration control mode, it can be considered unlikely that the vehicle body 1 will stop moving, so this routine is executed from the beginning. As a result, the timer is reset to zero. 【0041】 Furthermore, the controller 10 executes this routine from the beginning when it determines that the forward / reverse lever 21 is set to neutral (No in step ST13) and when it determines that the operator has pressed the brake pedal 38 (No in step ST14). In this case, since the operator is intentionally trying to stop the vehicle 1 from moving, it is considered that the vehicle 1 will not start moving unintentionally. 【0042】 Furthermore, the controller 10 also executes this routine from the beginning when it determines that the operator has pressed the accelerator pedal 37 again (No in step ST15). If the accelerator pedal 37 is pressed again, it is assumed that the operator has determined that there is no risk of the vehicle body 1 and the obstacle 50 coming into contact even if the vehicle body 1 is accelerated, for example, because the obstacle 50 has moved away from the vicinity of the vehicle body 1. In other words, since the operator intentionally tried to accelerate the vehicle body 1, it can be said that stopping the vehicle body 1 itself is unnecessary. 【0043】 Furthermore, the controller 10 also executes this routine from the beginning when it determines that the vehicle speed V of the vehicle body 1 is greater than a predetermined speed Vref (No in step ST16). In this way, if any of the operating conditions in steps ST12 to ST16 are not met, or if any of the operating conditions were met once but become unmet before the predetermined time Δt has elapsed, the parking brake device 13d will not be automatically activated. 【0044】 Returning to the explanation of Figure 6, after the controller 10 activates the parking brake device 13d in step ST21, it does not permit the release of the parking brake device 13d (step ST22). Next, the controller 10 determines whether the operator has set the forward / reverse lever 21 to neutral (N) (step ST23). If the controller 10 determines that the forward / reverse lever 21 is not set to neutral (No in step ST23), it returns to step ST22 and maintains the current state. In this case, even if the operator instructs to release the parking brake device 13d using the parking brake switch 26, the controller 10 will not release the parking brake device 13d. 【0045】 Meanwhile, when the controller 10 determines that the forward / reverse lever 21 is set to neutral (Yes in step ST23), it permits the release of the parking brake device 13d (step ST24) and terminates this routine. As a result, when the operator instructs to release the device using the parking brake switch 26, the parking brake device 13d is released, and the restriction on the movement of the vehicle 1 ends. 【0046】 As described above, in the tire roller (construction machine) 100 of the embodiment, the controller (control device) 10 performs a stop brake control by activating the parking brake device (brake device) 13d (step ST21) when the vehicle speed V falls below a predetermined speed Vref (step ST16) during deceleration control. With this configuration, when the vehicle body 1 stops moving due to deceleration control of the vehicle body 1 due to obstacle detection, it is possible to prevent the vehicle body 1 from starting to move unintentionally by the operator. 【0047】 Furthermore, the controller 10 does not activate the parking brake device 13d until a predetermined time Δt has elapsed after the vehicle speed V falls below a predetermined speed Vref during deceleration control, and activates the parking brake device 13d once the predetermined time Δt has elapsed after the vehicle speed V falls below a predetermined speed Vref during deceleration control. This configuration makes it possible to suppress frequent unnecessary activation of the parking brake device 13d. 【0048】 Furthermore, after the parking brake device 13d is activated during braking control while stopped, the controller 10 does not allow the release of the parking brake device 13d until the forward / reverse lever 21 is set to neutral, and then allows the release of the parking brake device 13d once the forward / reverse lever 21 is set to neutral (steps ST22 to ST24). This configuration prevents the operator from unintentionally releasing the parking brake device 13d. 【0049】 Furthermore, the controller 10 activates the parking brake device 13d when, during deceleration control, the vehicle speed V falls below a predetermined speed Vref, the direction of travel of the vehicle body 1 is set to forward or reverse by the forward / reverse lever 21 (Yes in step ST13), and the brake pedal 38 is not pressed (Yes in step ST14). This configuration avoids unnecessary activation of the parking brake device 13d when the operator intends to stop the vehicle body 1 from moving. 【0050】 Furthermore, the controller 10 activates the parking brake device 13d when the vehicle speed V falls below a predetermined speed Vref during deceleration control, and the operator has not pressed the accelerator pedal 37 again after releasing it (Yes in step ST15). This configuration avoids unnecessary activation of the parking brake device 13d when the operator intends to accelerate the vehicle 1. 【0051】 Furthermore, the controller 10 activates the parking brake device 13d when any of the following predetermined conditions are met during deceleration control: when the vehicle speed V falls below a predetermined speed Vref and the hydraulic fluid temperature is above a predetermined temperature; when the aftertreatment device 12 is performing regeneration control; or when the inclination angle during uphill driving is above a predetermined angle (Yes in step ST12). This configuration makes it possible to avoid unnecessary activation of the parking brake device 13d when conditions are not such that the vehicle body 1 is likely to stop moving unintentionally. 【0052】 Furthermore, the controller 10 activates the parking brake device 13d during braking control when the vehicle is stopped. This configuration allows for more reliable prevention of unintended movement of the vehicle body 1 by keeping it in a parked state. 【0053】 This concludes the description of the embodiments, but the aspects of the present invention are not limited to these embodiments. For example, in this embodiment, the present invention is applied to a tire roller 100, but the present invention may also be applied to compaction machines other than tire rollers 100, or other construction machines such as hydraulic excavators. In addition, in braking control when stopping, a service brake device 13e may be used instead of a parking brake device 13d. Furthermore, the processes of steps ST12 to ST15 in Figure 5 may be performed only in part, or all of them may be omitted. Also, the processes of steps ST17 to ST19 in Figure 6 may be omitted. That is, the parking brake device 13d may be activated when the vehicle speed V becomes less than or equal to a predetermined speed Vref. [Explanation of Symbols] 【0054】 1. Vehicle body 3. Front wheels 4 Rear wheel (wheel) 5. Drive Unit 10. Controller (control device) 11. Engine (prime mover) 12 Post-processing equipment 13 HST 13a Hydraulic pump (hydraulic pump for travel) 13b Hydraulic motor (hydraulic motor for travel) 13c Hydraulic pathway 13d Parking brake device 13e Service Brake System 21 Forward / Forward Lever 26 Parking brake switch 41. Hydraulic oil temperature sensor (hydraulic oil temperature detection device) 42. Tilt Sensor (Tilt Angle Detection Device) 43. Infrared sensor (obstacle detection device) 45. Rotation sensor (vehicle speed detection device, direction of travel detection device) 100 Tire Roller (Construction Machinery)

Claims

[Claim 1] The car body and, The wheels provided on the vehicle body, The engine installed in the vehicle body, A hydraulic pump for travel, driven by the aforementioned prime mover, A hydraulic motor is connected in a closed circuit to the aforementioned hydraulic pump for driving, and outputs driving force to the wheels. A braking device for maintaining the vehicle body in a stationary state, A vehicle speed detection device that detects vehicle speed, An obstacle detection device for detecting obstacles located around the vehicle body, When the obstacle detection device detects an obstacle within a predetermined distance or less from the vehicle body while the vehicle body is in motion, the control device performs deceleration control to reduce the rotational speed of the prime mover and decelerate the vehicle body. In construction machinery equipped with, The control device is characterized in that, during the execution of the deceleration control, if the vehicle speed detected by the vehicle speed detection device falls below a predetermined speed, it performs a stopping brake control that activates the brake device. [Claim 2] The construction machine according to claim 1, characterized in that the control device does not activate the brake device during the execution of the deceleration control until a predetermined time has elapsed after the vehicle speed falls below the predetermined speed, and activates the brake device during the execution of the deceleration control once the predetermined time has elapsed after the vehicle speed falls below the predetermined speed. [Claim 3] The vehicle is equipped with a forward / reverse lever to set the direction of travel of the vehicle body to forward, reverse, or neutral. The construction machine according to claim 1, characterized in that the control device does not permit the release of the brake device after the brake device has been activated in the braking control during stopping until the forward / reverse lever is set to neutral, and permits the release of the brake device once the forward / reverse lever is set to neutral. [Claim 4] The vehicle is equipped with a forward / reverse lever to set the direction of travel of the vehicle body to forward, reverse, or neutral. The construction machine according to claim 1, characterized in that the control device performs the stopping brake control when the vehicle speed becomes less than or equal to the predetermined speed and the direction of travel of the vehicle body is set to forward or reverse by the forward / reverse lever during the execution of the deceleration control. [Claim 5] The brake pedal is equipped with a brake that adjusts the braking force of the aforementioned brake device according to the amount of pressure applied by the operator. The construction machine according to claim 1, characterized in that the control device performs the stopping brake control when the vehicle speed becomes below the predetermined speed and the brake pedal is not pressed during the execution of the deceleration control. [Claim 6] The vehicle is equipped with an accelerator pedal that adjusts the acceleration and deceleration of the vehicle body by the amount of pressure applied by the operator. The construction machine according to claim 1, characterized in that the control device performs the stopping brake control when the vehicle speed becomes below the predetermined speed during the execution of the deceleration control and the operator has not pressed the accelerator pedal again after releasing it. [Claim 7] The system includes a hydraulic fluid temperature detection device for detecting the temperature of the hydraulic fluid supplied to the hydraulic pump and the hydraulic motor for travel, The construction machine according to claim 1, characterized in that the control device executes the stopping brake control when the vehicle speed becomes below the predetermined speed and the temperature of the hydraulic fluid detected by the hydraulic fluid temperature detection device is above the predetermined temperature during the execution of the deceleration control. [Claim 8] The system includes an aftertreatment device for collecting particulate matter in the exhaust gas of the internal combustion engine that constitutes the prime mover, The construction machine according to claim 1, characterized in that the control device performs the stopping brake control when the vehicle speed becomes below the predetermined speed and the regeneration control of the aftertreatment device that raises the temperature of the exhaust gas of the internal combustion engine is being performed during the execution of the deceleration control. [Claim 9] The vehicle body is equipped with a tilt angle detection device that detects the tilt angle of the vehicle body, The construction machine according to claim 1, characterized in that the control device executes the stopping brake control when the vehicle speed becomes less than or equal to the predetermined speed during the execution of the deceleration control and the inclination angle detected by the inclination angle detection device during uphill climbing is greater than or equal to the predetermined angle. [Claim 10] The aforementioned braking device consists of a parking brake device for parking the vehicle body. The construction machine according to any one of claims 1 to 9, characterized in that the control device activates the parking brake device in the braking control when stopping.

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