JP6567404B2 - Vehicle brake system - Google Patents

Description

  The present invention relates to a brake system for a vehicle that generates a braking force to decelerate or stop the vehicle.

  Conventionally, as a vehicle such as a transport vehicle or rough terrain vehicle used in frozen soil or muddy ground, a hydraulic motor is rotated by a hydraulic pump that is driven according to an operation amount of an accelerator operating means, and a pair of left and right axles is driven by the hydraulic motor There is known one provided with traveling drive means for rotating the wheel. Moreover, many conventional transport vehicles and rough terrain vehicles travel at a relatively low speed, but in recent years, an increasing number of vehicles travel at a relatively high speed of 30 km / h or more.

  The vehicle is provided with brake means for releasing braking of the vehicle when hydraulic oil is supplied from the hydraulic pump via the brake pilot pipeline, an electromagnetic switching valve disposed in the brake pilot pipeline, and an accelerator operation. A brake having a control means for detecting an operation state of the means, opening the electromagnetic switching valve during the operation of the accelerator operating means, and closing the electromagnetic switching valve after a predetermined delay time has elapsed since the operation signal is in a non-input state. A system is provided (see, for example, Patent Document 1).

  The reason why the delay time is given to the operation of the electromagnetic switching valve is to generate a braking force on the brake means after the vehicle is completely stopped. Since the hydraulic motor does not stop rotating immediately after the hydraulic oil is not supplied, the vehicle travels by inertia until the hydraulic motor stops rotating. If the brake means is operated while the vehicle is traveling inertia, an impact is generated when the vehicle is stopped, and a load is applied to the brake means. Therefore, a delay time is given to the operation of the electromagnetic switching valve.

JP 05-106244 A

  As described above, the current vehicle traveling at a relatively high speed has a longer time until the hydraulic motor stops rotating than the conventional low-speed vehicle. It is necessary to set a long delay time until operation. However, if the delay time of the electromagnetic switching valve is lengthened, the distance that the vehicle travels by inertia is also lengthened. Therefore, the deviation between the stop position intended by the driver and the actual stop position becomes large, which may be dangerous. .

  In order to make it possible to stop the vehicle urgently, the electromagnetic switching valve can be opened manually to apply sudden braking, but the braking force cannot be controlled, so the shock during sudden braking increases, which may be dangerous. Conceivable. In addition, the sudden braking is inferior in sensitivity compared with the case where the braking force is controlled so as to gradually change.

  In order to solve the above-mentioned problems, an object of the present invention is to provide a vehicle brake system that has a small shock during sudden braking of the vehicle and that can provide a sensitive brake operation feeling.

  In order to solve the above-mentioned problem, the invention described in claim 1 is a travel drive unit that rotates a hydraulic motor by a hydraulic pump that is driven according to an operation amount of an accelerator operation unit, and rotates a pair of left and right axles by the hydraulic motor. A brake means for releasing the braking of the vehicle when hydraulic oil is supplied from the hydraulic pump via the brake pilot line, and an electromagnetic switching valve disposed in the brake pilot line. A control means for detecting an operating state of the accelerator operating means, opening the electromagnetic switching valve during the operation of the accelerator operating means, and closing the electromagnetic switching valve after a predetermined delay time has elapsed after the operation signal is not input. A brake system for a vehicle provided. The brake system further includes a bypass pipe that bypasses the electromagnetic switching valve and connects the hydraulic pump and the brake device, and an electromagnetic proportional pressure reducing valve that is disposed in the bypass pipe. The amount of opening of the electromagnetic proportional pressure reducing valve is adjusted so as to be proportional to the operation amount of the brake operation means operated when decelerating or stopping the engine, and the hydraulic pressure of the hydraulic oil supplied to the brake means is reduced.

  According to the present invention, when the brake operation means is operated, the opening amount of the electromagnetic proportional pressure reducing valve is adjusted so as to be proportional to the operation amount, and the hydraulic pressure of the hydraulic oil supplied to the brake means is reduced. That is, a braking force is generated in the brake means so as to be proportional to the operation amount of the brake operation means, and the vehicle is decelerated or stopped.

  According to a second aspect of the present invention, in the vehicle brake system according to the first aspect, the control means operates the electromagnetic proportional pressure reducing valve until the operation amount of the brake operation means reaches a predetermined operation amount. It has a dead zone that is not performed.

  According to a third aspect of the present invention, in the vehicle brake system according to the second aspect, the control means is an electromagnetic proportional pressure reduction so that the control means is proportional to the operation amount of the brake operation means linearly or in a multi-order curve. This is to adjust the opening of the valve.

  According to a fourth aspect of the present invention, in the vehicle brake system according to any one of the first to third aspects, a pair of left and right planetary gear mechanisms respectively connected to a pair of left and right axles as travel drive means; Power from a traveling hydraulic motor is input to the sun gears of a pair of left and right planetary gear mechanisms to rotate a pair of axles in the same direction and at the same speed, and a pair of left and right power from a turning hydraulic motor. And a turning drive system that causes the difference between the rotational speeds of the pair of left and right axles to be input to the ring gear of the planetary gear mechanism and rotated in opposite directions.

  According to the first aspect of the present invention, when the brake operation means is operated, the opening amount of the electromagnetic proportional pressure reducing valve is adjusted so as to be proportional to the operation amount, and the hydraulic pressure of the hydraulic oil supplied to the brake means is adjusted. By reducing the braking force, the braking force can be generated in the brake means so as to be proportional to the operation amount of the brake operating means, so that the impact when the vehicle is stopped urgently can be reduced. In addition, since the vehicle can be gradually decelerated and stopped, it is possible to obtain a sensitive brake operation feeling.

  According to the second aspect of the present invention, even when the brake operating means is operated more strongly than the driver intends when the vehicle is stopped urgently, the electromagnetic proportional pressure reducing valve is immediately activated by the predetermined dead zone. Since it does not operate, the impact generated by the deceleration of the vehicle can be reduced.

  According to the third aspect of the present invention, the opening amount of the electromagnetic proportional pressure reducing valve is proportional to the operation amount of the brake operation means linearly or in a multi-order curve in accordance with the operation feeling of the brake operation means. As a result, the brake operation feeling excellent in sensitivity can be obtained.

  According to the fourth aspect of the present invention, the traveling drive means includes a pair of left and right planetary gear mechanisms, a traveling drive system, and a turning drive system, and the brake system can be used for a vehicle traveling at a relatively high speed. Even when the vehicle travels by inertia until the braking means generates braking force after the delay time has elapsed, the vehicle can be stopped urgently.

It is a perspective view which shows the chassis part of the vehicle with which the traveling drive device of 1st Embodiment was attached. It is an external appearance perspective view of the travel drive device of a 1st embodiment. It is sectional drawing of the horizontal direction of the traveling drive apparatus of 1st Embodiment. It is a power transmission block diagram of the traveling drive device of a 1st embodiment. It is a control block diagram which shows the hydraulic system and electric system of the traveling drive apparatus of 1st Embodiment. It is a timing chart of the brake system of a 1st embodiment. It is a power transmission block diagram of the travel drive apparatus of 2nd Embodiment.

(Embodiment 1)
The present invention will be described below based on the illustrated embodiments.

  FIG. 1 is a perspective view showing a chassis portion of a vehicle 2 to which a travel drive device (travel drive means) 1 according to the present embodiment is attached. The vehicle 2 is, for example, a transport vehicle used on frozen soil or muddy ground, or a rough terrain vehicle, and is a vehicle that travels at a relatively higher speed than agricultural machinery or construction vehicles. The vehicle 2 has a vehicle front portion on the right side in the drawing and a vehicle rear portion on the left side in the drawing, and has chassis 3L and 3R arranged along the front-rear direction on both sides of the vehicle 2. The chassis 3L, 3R are integrated by a plurality of frames (not shown) arranged in the width direction of the vehicle 2. The travel drive device 1 is disposed at the rear of the vehicle and is fixed to the chassis 3L, 3R by a pair of left and right shaft support members 4L, 4R and a lower frame (not shown) that supports the lower portion of the travel drive device 1. Has been. In addition, an engine 5 serving as a power source of the traveling drive device 1, a traveling hydraulic pump 6 and a turning hydraulic pump 7 (see FIG. 5) driven by the engine 5 are disposed in the front portion of the vehicle 2. .

  The vehicle 2 includes a pair of left and right crawlers 8L and 8R when the vehicle 2 is viewed from the rear. The pair of left and right crawlers 8L and 8R includes a pair of drive wheels 10L and 10R rotated by a pair of left and right axles 9L and 9R (see FIG. 3) provided in the travel drive device 1, and a chassis 3L at the rear of the vehicle 2. An idler wheel (not shown) fixed to 3R and biased forward, crawler belts 11L and 11R wound around drive wheels 10L and 10R and idler wheels, and chassis 3L and 3R A plurality of lower rollers 12L, 12R that support the lower inner peripheral surfaces of the crawler belts 11L, 11R are provided. The vehicle 2 moves straight forward or backward as the left and right drive wheels 10L, 10R rotate at the same speed, and turns left or right forward or backward as the left and right drive wheels 10L, 10R rotate at different speeds. Turn. In addition, the vehicle 2 makes a super turn as the left and right drive wheels 10L and 10R rotate in opposite directions.

  FIG. 2 is an external perspective view of the travel drive device 1, FIG. 3 is a horizontal sectional view of the travel drive device 1, and FIG. 4 is a power transmission block diagram of the travel drive device 1. The travel drive device 1 accommodates and integrates main components such as a travel input shaft 14, a turning input shaft 15, and a pair of left and right planetary gear mechanisms 16 </ b> L and 16 </ b> R in one case 13. The case 13 is roughly divided into a gear case 17 that accommodates the planetary gear mechanisms 16L and 16R, a shaft case 18 that accommodates the traveling input shaft 14 and the turning input shaft 15, and a brake case 19 described later. It is composed of a pair of left and right side cases 20L, 20R and axle cases 21L, 21R.

  The brake case 19 is a substantially box-shaped case attached to the vehicle front side of the shaft case 18, and includes two attachment spigots 19a to which a traveling hydraulic motor (hydraulic motor) 22 and a turning hydraulic motor 23 are attached. 19b. The traveling hydraulic motor 22 and the turning hydraulic motor 23 are rotated by hydraulic oil supplied from the traveling hydraulic pump 6 and the turning hydraulic pump 7 disposed in the front part of the vehicle. Further, in the brake case 19, a traveling brake (brake means) 24 that cuts off power transmission from the traveling hydraulic motor 22 and the turning hydraulic motor 23 to the traveling input shaft 14 and the turning input shaft 15, and turning A brake 25 is incorporated.

  The traveling brake 24 and the turning brake 25 constitute a braking system of the present invention, and are a so-called negative brake. The traveling brake 24 and the turning brake 25 generate a braking force by pressing a friction plate and a separate plate via a brake piston by a spring (not shown), and hydraulic oil is supplied to the brake piston. The braking force is released when the pressing of the plate and the separate plate is released. The traveling brake 24 is operated when the vehicle 2 turns in a super-confident manner. The turning brake 25 is operated when the vehicle 2 travels straight. Furthermore, the traveling brake 24 and the turning brake 25 function as a parking brake that brakes the stopped vehicle 2 in addition to a service brake that reduces the speed according to the operation of the driver while the vehicle 2 is traveling. .

  The travel hydraulic motor 22, the travel brake 24, and the travel input shaft 14 constitute a travel drive system 1 </ b> A that causes the vehicle 2 to move forward or backward in the travel drive device 1. The traveling input shaft 14 transmits the driving force of the traveling hydraulic motor 22 to the planetary gear mechanisms 16L and 16R. Between the traveling brake 24 and the traveling input shaft 14, a speed change mechanism 33 that decelerates the driving force of the traveling hydraulic motor 22 is provided.

  Further, the turning hydraulic motor 23, the turning brake 25, and the turning input shaft 15 constitute a turning drive system 1B for turning the vehicle 2 left and right in the travel drive device 1. The turning input shaft 15 transmits the driving force of the turning hydraulic motor 23 to the planetary gear mechanisms 16L and 16R.

  The traveling input shaft 14 and the turning input shaft 15 are coaxially arranged, and the traveling input shaft 14 passes through the turning input shaft 15 formed in a cylindrical shape. The traveling drive system 1A and the turning drive system 1B are arranged in parallel in the left-right direction so as to sandwich the traveling input shaft 14 and the turning input shaft 15.

  The pair of left and right planetary gear mechanisms 16L and 16R includes sun gears 44L and 44R, three planetary gears 46L and 46R that are supported by gear holders 45L and 45R and mesh with the sun gears 44L and 44R, respectively, and three planetary gears. 46L and 46R are comprised from the cylindrical ring gear 47L and 47R with which the tooth row meshed | engaged was provided in the inner surface. A pair of left and right axles 9L and 9R are connected to the left and right gear holders 45L and 45R, respectively. The gear holders 45L, 45R and the ring gears 47L, 47R are rotatably supported via a plurality of bearings by bearings provided inside the side cases 20L, 20R.

  When the traveling input shaft 14 rotates, the rotation is transmitted to the left and right sun gears 44L, 44R. The rotation of the sun gears 44L, 44R is transmitted to the axles 9L, 9R via the planetary gears 46L, 46R and the gear holders 45L, 45R. As a result, the pair of left and right axles 9L and 9R rotate in the same direction and at the same speed, so the vehicle 2 goes straight. When the turning input shaft 15 rotates, the rotation is transmitted to the left and right ring gears 47L, 47R, and the left and right ring gears 47L, 47R rotate in opposite directions. Since the rotation of the ring gears 47L and 47R is transmitted to the axles 9L and 9R via the planetary gears 46L and 46R, a difference occurs in the rotational speeds of the left and right axles 9L and 9R, and the vehicle 2 turns to the side where the rotational speed is slow. To do.

  FIG. 5 is a control block diagram showing a hydraulic system and an electric system of the travel drive device 1. The control device (control means) 50 is a computer including a CPU (Central Processing Unit) and a storage medium storing a program processed by the CPU, and comprehensively controls each part of the vehicle 2. A data bus 51 connected to the control device 50 includes an accelerator pedal (accelerator operation means) 52, a forward / reverse switching lever 53, a shift lever 54, a brake pedal (brake operation means) 55 provided in the driver's seat of the vehicle 2, Operation signals from the steering wheel 56 and the super-spinning turning mode changeover switch 57 are input.

  In response to an operation signal input to the data bus 51, the control device 50 includes the engine 5, the traveling hydraulic pump 6, the turning hydraulic pump 7, the traveling hydraulic motor 22, the turning hydraulic motor 23, the electromagnetic switching valve 58A, An instruction signal is transmitted to 58B, 58C and the electromagnetic proportional pressure reducing valve 60 for control. More specifically, the control device 50 changes the rotational speed of the engine 5 and the flow rate of the traveling hydraulic pump 6 in accordance with the operation amount of the accelerator pedal 52, and performs an automotive control for adjusting the straight traveling speed of the vehicle 2. Do. The control device 50 adjusts the turning speed and the turning amount of the vehicle 2 by changing the flow rate of the turning hydraulic pump 7 according to the operation amount of the handle 56.

  The engine 5 is, for example, a diesel engine that can obtain a high torque from a low speed rotation. The traveling hydraulic pump (hydraulic pump) 6 and the turning hydraulic pump 7 are connected to the engine 5 and driven. The traveling hydraulic pump 6 is a closed circuit pump, and is a variable displacement hydraulic pump provided with a bidirectional tilting mechanism in which the suction port and the discharge port can be reversed. The traveling hydraulic pump 6 switches the hydraulic oil circulation direction in the main pipelines 61 </ b> A and 61 </ b> B in response to a switching command for the forward position F or the reverse position R of the forward / reverse switching lever 53. When the vehicle 2 travels forward, the traveling hydraulic pump 6 sucks hydraulic oil from the main pipeline 61A and discharges hydraulic fluid to the main pipeline 61B. Conversely, when the vehicle 2 travels backward, the traveling hydraulic pump 6 sucks hydraulic oil from the main pipeline 61B and discharges hydraulic fluid to the main pipeline 61A.

  The turning hydraulic pump 7 is similarly a closed circuit pump, and is a variable displacement hydraulic pump provided with a bi-directional tilt mechanism capable of reversing the suction port and the discharge port. The turning hydraulic pump 7 switches the circulation direction of the hydraulic oil in the main pipelines 62A and 62B in accordance with an operation command for the handle 56. For example, when the vehicle 2 turns left, the turning hydraulic pump 7 sucks hydraulic oil from the main pipeline 62B and discharges hydraulic fluid to the main pipeline 62A. Conversely, when the vehicle 2 turns to the right, the turning hydraulic pump 7 sucks hydraulic oil from the main pipeline 62A and discharges hydraulic fluid to the main pipeline 62B.

  The traveling hydraulic pump 6 has a built-in pilot pump, and the discharge port 6a and the electromagnetic switching valves 58A to 58C are connected by a pilot line 63. The pilot line 63 is provided with a check valve 64 for preventing leakage of hydraulic oil from the electromagnetic switching valves 58A to 58C to the pilot pump when the vehicle 2 is stopped, and an accumulator 65 for maintaining pressure. Between the electromagnetic switching valves 58A, 58B, and 58C and the speed change mechanism 33, the travel brake 24, and the turning brake 25, a speed change pilot line 66 and a travel brake pilot line (brake pilot line) 67 are provided. Are connected by a pilot line 68 for turning brake.

  The control device 50 opens the valve of the electromagnetic switching valve 58A in response to the switching command of the transmission lever 54, and discharges hydraulic oil to the hydraulic cylinder of the transmission mechanism 33 via the transmission pilot pipe 66, thereby causing the transmission mechanism 33 to operate. Change speed. The control device 50 also functions as a control unit for a brake system including the traveling brake 24 and the turning brake 25. When the operation signal is not input from the accelerator pedal 52, that is, when the vehicle 2 is stopped. The electromagnetic switching valves 58B and 58C are closed, the supply of hydraulic oil to the traveling brake pilot pipe 67 and the turning brake pilot pipe 68 is stopped, and a braking force is generated in the traveling brake 24 and the turning brake 25. It functions as a parking brake. Further, when the operation signal is input from the accelerator pedal 52 and the vehicle 2 starts to travel, the control device 50 opens the solenoid switching valves 58B and 58C to open the traveling brake pilot pipe 67 and the turning brake. The hydraulic oil is supplied to the pilot pipe 68, and the braking by the traveling brake 24 and the turning brake 25 is released.

  Further, as shown in the timing chart of FIG. 6, when the operation signal is not input from the accelerator pedal 52 while the vehicle 2 is traveling, the control device 50 starts from the time T1 when the operation of the accelerator pedal 52 is stopped. The electromagnetic switching valves 58B and 58C are closed at time T2 after the elapse of the predetermined delay time Td, and the supply of hydraulic oil to the traveling brake 24 and the turning brake 25 is stopped to generate a braking force.

  The reason why the delay time Td is given to the operation of the electromagnetic switching valves 58B and 58C is to generate a braking force on the traveling brake 24 and the turning brake 25 after the vehicle 2 is completely stopped. Since the traveling hydraulic motor 22 and the turning hydraulic motor 23 do not stop rotating immediately after the hydraulic oil is not supplied, in the vehicle 2, the traveling hydraulic motor 22 and the turning hydraulic motor 23 stop rotating. Travel with inertia. If the driving brake 24 and the turning brake 25 are operated while the vehicle 2 is running inertia, an impact is generated when the vehicle 2 stops, and a load is applied to the driving brake 24 and the turning brake 25. End up. Therefore, a delay time Td is given to the operation of the electromagnetic switching valves 58B and 58C.

  Since the vehicle 2 of the present embodiment has a higher traveling speed than conventional agricultural equipment and the like, it takes a longer time for the traveling hydraulic motor 22 and the turning hydraulic motor 23 to stop rotating. Therefore, in the vehicle 2 of the present embodiment, it is necessary to set the delay time Td until the electromagnetic switching valves 58B and 58C operate longer than the conventional agricultural equipment, and the distance that the vehicle 2 travels by inertia is also increased. End up. However, if the distance that the vehicle 2 travels by inertia increases, the shift between the stop position intended by the driver and the actual stop position increases, and therefore, a dangerous case can be considered. The electromagnetic switching valves 58B and 58C can be opened manually to suddenly brake the vehicle 2. However, since the braking force cannot be controlled, the shock at the time of sudden braking becomes large, and conversely, it may be dangerous. In addition, the sudden braking is insensitive to the case of controlling the braking force. Therefore, in the present embodiment, in order to be able to stop the vehicle 2 by operating the brake pedal 55 during the delay time Td, the electromagnetic proportional pressure reducing valve 60, the bypass conduit 69, the travel brake bypass conduit 70, and the turn A brake bypass pipe 71 and check valves 72 and 73 are provided.

  For example, when the brake pedal 55 is operated at time T3 during the delay time Td, the control device 50 adjusts the opening amount of the electromagnetic proportional pressure reducing valve 60 so as to be proportional to the operation amount of the brake pedal 55 to The hydraulic pressure of the hydraulic oil supplied to the brake 24 and the turning brake 25 is reduced. The brake pedal 55 is operated stronger than intended by the driver at the start of the operation, and an impact due to deceleration is often generated in the vehicle 2. Therefore, in the present embodiment, a predetermined dead zone F that does not react to the operation of the brake pedal 55 is provided so that a braking force is not generated immediately even if the brake pedal 55 is operated. Therefore, the electromagnetic proportional pressure reducing valve 60 is opened at the timing of time T4 when the brake pedal 55 is operated beyond the dead zone F.

  When the electromagnetic proportional pressure reducing valve 60 is opened, the hydraulic oil supplied to the traveling brake 24 and the turning brake 25 is detoured from the traveling brake pilot line 67 and the turning brake pilot line 68. It flows into the pipeline 70 and the bypass brake bypass pipeline 71. As a result, the hydraulic pressure of the hydraulic oil supplied to the traveling brake 24 and the turning brake 25 gradually decreases as indicated by the broken line indicated by the symbol P. Therefore, the traveling brake 24 and the turning brake 25 are connected to the brake pedal 55. The braking force corresponding to the operation amount is generated, and the vehicle 2 stops at the timing of time T5. Thus, the vehicle 2 can be stopped according to the amount of operation of the brake pedal 55 even during the delay time Td from when the accelerator operation is released until the vehicle 2 is completely stopped.

  The operation of the electromagnetic proportional pressure reducing valve 60 is changed to a multi-order curve shape indicated by a symbol M1 in accordance with the operation feeling of the brake pedal 55, but is linear like a two-dot chain line indicated by a symbol M2. You may make a transition to. In this case, the hydraulic pressure P of the hydraulic oil supplied to the traveling brake 24 and the turning brake 25 also changes linearly.

  Next, the operation of the first embodiment will be described. When the engine 5 is started, the control device 50 rotates the engine 5 at a predetermined rotational speed, and drives the traveling hydraulic pump 6 and the turning hydraulic pump 7 at a flow rate corresponding to the idling rotation. Since the vehicle 2 is braked by the traveling brake 24 and the turning brake 25 that function as a parking brake, the vehicle 2 does not travel at the flow rates of the traveling hydraulic pump 6 and the turning hydraulic pump 7 based on idling rotation.

  When the accelerator pedal 52 is operated, the control device 50 opens the electromagnetic switching valve 58B, supplies hydraulic oil to the traveling brake 24, and releases the braking. Further, the control device 50 drives the traveling hydraulic motor 22 by adjusting the rotational speed of the engine 5 and the flow rate of the traveling hydraulic pump 6 according to the operation amount of the accelerator pedal 52. The power of the traveling hydraulic motor 22 is transmitted to the pair of left and right axles 9L and 9R via the traveling speed reduction mechanism 26, the traveling input shaft 14, and the pair of left and right planetary gear mechanisms 16L and 16R. Since the vehicle 2 rotates in the same direction at the same speed, the vehicle 2 starts to travel straight at a speed corresponding to the operation amount of the accelerator pedal 52.

  When the handle 56 is operated while the vehicle 2 is traveling, the control device 50 opens the electromagnetic switching valve 58C, supplies hydraulic oil to the turning brake 25, and releases the braking. Further, the flow rate of the turning hydraulic pump 7 is adjusted according to the operation amount, and the turning hydraulic motor 23 is driven. The power of the turning hydraulic motor 23 is transmitted to the pair of left and right planetary gear mechanisms 16L and 16R via the turning speed reduction mechanism 27 and the turning input shaft 15, and the planetary gear mechanisms 16L and 16R are at the same speed in opposite directions. Rotate. As a result, a difference occurs in the rotational speeds of the axles 9L and 9R, so that the vehicle 2 turns at a direction and speed corresponding to the operation amount of the handle 56.

  When the operation of the accelerator pedal 52 is stopped while the vehicle 2 is traveling, the control device 50 closes the electromagnetic switching valves 58B and 58C after a predetermined delay time Td has elapsed from the stop of the operation of the accelerator pedal 52, and the traveling brake The supply of hydraulic oil to the brake 24 and the turning brake 25 is stopped to generate a braking force. When the brake pedal 55 is operated beyond the dead zone F during the delay time Td, the control device 50 adjusts the opening amount of the electromagnetic proportional pressure reducing valve 60 so as to be proportional to the operation amount of the brake pedal 55, and travels. The hydraulic oil pressure supplied to the brake 24 and the turning brake 25 is reduced. As a result, the hydraulic oil supplied to the traveling brake 24 and the turning brake 25 passes from the traveling brake pilot line 67 and the turning brake pilot line 68 to the traveling brake detour line 70 and the turning brake detour. Since the hydraulic pressure of the hydraulic oil flowing into the pipeline 71 and supplied to the traveling brake 24 and the turning brake 25 decreases, the traveling brake 24 and the turning brake 25 are controlled according to the operation amount of the brake pedal 55. Generate power. Therefore, the vehicle 2 stops according to the operation of the brake pedal 55 even during the delay time Td.

  According to the present embodiment, when the brake pedal 55 is operated, the opening amount of the electromagnetic proportional pressure reducing valve 60 is adjusted so as to be proportional to the operation amount, and supplied to the traveling brake 24 and the turning brake 25. By reducing the hydraulic pressure of the hydraulic oil, a braking force can be generated in the traveling brake 24 and the turning brake 25 in proportion to the amount of operation of the brake pedal 55, so that when the vehicle 2 is stopped urgently Impact can be reduced. Further, since the vehicle 2 can be gradually decelerated and stopped, it is possible to obtain a sensitive brake operation feeling.

  Further, even when the brake pedal 55 is operated more strongly than the driver intends when stopping the vehicle 2 urgently, the electromagnetic proportional pressure reducing valve 60 is not immediately activated by the predetermined dead zone F. Therefore, the impact generated by the deceleration of the vehicle 2 can be reduced. Further, the opening amount of the electromagnetic proportional pressure reducing valve 60 is adjusted so as to be proportional to the operation amount of the brake pedal 55 linearly or in a multi-order curve in accordance with the operation feeling of the brake pedal 55. An excellent brake operation feeling can be obtained.

  In addition, the travel drive device 1 includes a pair of left and right planetary gear mechanisms 16L and 16R, a travel drive system 1A, and a turning drive system 1B, and a brake system can be used for the vehicle 2 that travels at a relatively high speed. Even when the vehicle 2 travels by inertia until the braking brake 24 and the turning brake 25 generate braking force after the delay time Td has elapsed, the vehicle 2 can be stopped urgently.

(Embodiment 2)
Next, a second embodiment of the present invention will be described. In addition, about the same component as 1st Embodiment, detailed description is abbreviate | omitted using a same sign. FIG. 7 is a power transmission block diagram of the travel drive device 80 to which the second embodiment is applied. In this travel drive device 80, contrary to the travel drive device 1 of the first embodiment, the travel input shaft 14 has a cylindrical shape, and the travel input shaft 15 is passed through the turning input shaft 15. . In the traveling drive device 1, a plurality of bevel gears are used to connect the traveling input shaft 14 and the turning input shaft 15 to the pair of left and right planetary gear mechanisms 16 </ b> L and 16 </ b> R. Using the spur gear and the transmission gears 81L and 81R provided on the outer periphery of the left and right ring gears 47L and 47R, the traveling input shaft 14 and the turning input shaft 15 are connected to a pair of left and right planetary gear mechanisms 16L and 16R. ing.

  In this way, the traveling input shaft 14 and the turning input shaft 15 can be arranged so as to penetrate either one to the other, and the traveling input shaft 14 and the turning input shaft 15 are input by one. It can arrange | position in the arrangement | positioning space of a shaft. The present invention can also be applied to the traveling drive device 80 that does not use a bevel gear, and the same effect can be obtained.

  As mentioned above, although each embodiment of this invention has been described in detail, the specific configuration is not limited to this embodiment, and even if there is a design change or the like without departing from the scope of this invention, It is included in this invention. For example, in the above-described embodiment, the description has been made by taking the transport vehicle and rough terrain vehicle used in frozen soil and muddy land as an example, but the present invention may be applied to agricultural machinery and construction vehicles. Moreover, although the crawler belt 2 has been described as an example, the present invention can be applied to a vehicle using tires.

DESCRIPTION OF SYMBOLS 1, 80 Travel drive device 1A Travel drive system 1B Turning drive system 2 Vehicle 5 Engine 6 Travel hydraulic pump (hydraulic pump)
7 Turning hydraulic pump 8L, 8R Crawler 9L, 9R Axle 13 Case 14 Traveling input shaft 15 Turning input shaft 16L, 16R Planetary gear mechanism 22 Traveling hydraulic motor (hydraulic motor)
23 Hydraulic motor for turning 24 Brake for traveling (brake means)
25 Brake for turning 33 Transmission mechanism 50 Control device (control means)
52 Accelerator pedal (accelerator operation means)
55 Brake pedal (brake operating means)
57 Super-revolution turning mode changeover switch 58A, 58B, 58C Electromagnetic switching valve 60 Electromagnetic proportional pressure reducing valve 67 Travel brake pilot line (brake pilot line)
69 Detour pipeline 70 Detour pipeline for driving F Dead zone

Claims (4)

Provided in a vehicle provided with traveling drive means for rotating a hydraulic motor by a hydraulic pump driven according to an operation amount of an accelerator operating means and rotating a pair of left and right axles by the hydraulic motor, and from the hydraulic pump to a pilot pipe for brake Detecting the operation state of the brake means for releasing the braking of the vehicle when the hydraulic oil is supplied through the road, the electromagnetic switching valve arranged in the pilot line for brake, and the accelerator operation means, A control unit that opens the electromagnetic switching valve during operation of the accelerator operating means and closes the electromagnetic switching valve after a predetermined delay time has elapsed since the accelerator operating means has become inoperative. There,
Bypassing the electromagnetic switching valve, and a bypass pipe connecting the hydraulic pump and the brake device;
An electromagnetic proportional pressure reducing valve disposed in the bypass line;
With
The control means adjusts an opening amount of the electromagnetic proportional pressure reducing valve so as to be proportional to an operation amount of a brake operation means operated when the vehicle is decelerated or stopped, and the hydraulic oil supplied to the brake means Reduce the hydraulic pressure of the
A brake system for a vehicle. The control means has a dead zone in which the electromagnetic proportional pressure reducing valve is not operated until the operation amount of the brake operation means reaches a predetermined operation amount set in advance.
The vehicle brake system according to claim 1. The control means adjusts the opening amount of the electromagnetic proportional pressure reducing valve so that it is proportional to the operation amount of the brake operation means linearly or in a multi-order curve.
The vehicle brake system according to claim 1, wherein the vehicle brake system is a vehicle brake system. The travel drive means includes
A pair of left and right planetary gear mechanisms respectively connected to the pair of left and right axles;
A driving drive system for inputting power from the hydraulic motor to the sun gears of the pair of left and right planetary gear mechanisms and rotating the pair of axles in the same direction at the same speed;
A turning drive system that inputs power from the hydraulic motor to the ring gears of the pair of left and right planetary gear mechanisms and rotates them in opposite directions to cause a difference in rotational speed between the pair of left and right axles;
The vehicle brake system according to any one of claims 1 to 3, further comprising:

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