WO1998001331A1

WO1998001331A1 - Travelling brake control device for industrial vehicle and control method

Info

Publication number: WO1998001331A1
Application number: PCT/JP1997/002366
Authority: WO
Inventors: Noboru Kanayama; Masaaki Genji
Original assignee: Komatsu Ltd.
Priority date: 1996-07-10
Filing date: 1997-07-08
Publication date: 1998-01-15
Also published as: JP3804876B2; KR100493556B1; KR980009671A; JPH1024822A

Abstract

A travelling brake control device for industrial vehicles and a control method therefor are provided, in which rear wheels can be safely braked without locking even when fully braked at the time of high speed travelling, and the rear wheels are braked as strongly as front wheels by a brake locking operation at the time of work to ensure a stable work. Therefore, a travelling brake control device for stopping a vehicle to perform work such as excavation, and loading and for braking the vehicle by means of front and rear wheel brakes at the time of travelling and work comprises a rear wheel brake valve (12) for reducing pressure of a pressure oil in a pressure source in accordance with an operating force of a brake pedal (25) to supply the rear wheel brakes with the oil, a front wheel brake valve (11) for operating interlockingly with the rear wheel brake valve to supply the front wheel brakes with a pressure oil of higher pressure than that of the pressure oil supplied to the rear wheel brakes, and rear wheel brake booster means for supplying a high pressure oil, which is to be supplied to the front wheel brakes, as a pressure oil for the rear wheel brakes at the time of work.

Description

Oki Meihoso Traveling brake control device for industrial vehicles and its control method

The present invention relates to a traveling brake control device for an industrial vehicle that performs braking during operation using a brake during traveling of the industrial vehicle, and a control method thereof. Background technology

In conventional industrial vehicles, when full braking is applied during driving, the downward load on the front wheels increases, but the downward load on the rear wheels decreases. Therefore, when the front wheels and the rear wheels have the same braking force, the rear wheels are easily locked. Locking the rear wheels not only reduces the braking force of the entire vehicle, but also makes it easier to spin, which is a problem from the viewpoint of safety.

As a technique for solving this problem, for example, Japanese Patent Publication No. 2-17004 has been proposed. According to the publication, an operating oil pressure lower than the operating oil pressure of the front wheel brake is supplied to the rear wheel brake to make the braking force of the rear wheel smaller than the braking force of the front wheel. In addition, the rear wheels require a large braking force, as do the front wheels, in order to work while the vehicle is stable during work. For this reason, the technique disclosed in the above publication has a problem in that when a large load is applied to the work equipment during work, the vehicle moves due to insufficient braking force on the rear wheels, and excavation cannot be performed.

In addition, vehicles with an upper revolving superstructure may work on the rear wheel side. If a large work load lifts the front wheel side, the rear wheel alone will support the load applied to the work equipment. For this reason, there is a problem that the vehicle becomes unstable if the braking force of the rear wheels is small. Disclosure of the invention

The present invention has been made in view of such a problem. Even when full-brake braking is applied during high-speed driving, the rear wheels can be safely braked without licking. It is an object of the present invention to provide a traveling brake control device and a control method for an industrial vehicle in which wheels can be braked as strongly as the front wheels and stable work can be performed.

In the first invention of the traveling brake control device for an industrial vehicle according to the present invention,

The running brake of an industrial vehicle that performs work such as excavation and loading with the mounted work machine, and brakes the vehicle during running and work with the front wheel brake having strong braking force and the rear wheel brake having weak braking force -The key control device operates the rear wheel brake valve in conjunction with the rear wheel brake valve and the rear wheel brake valve to reduce the pressure oil from the pressure source according to the operation force of the brake pedal and supply it to the rear wheel brake. A front wheel brake valve that supplies higher pressure oil to the front wheel brake than the pressure supplied to the front wheel brake, and a rear wheel brake booster that supplies high pressure oil to be supplied to the front wheel brake as pressure oil for the rear wheel brake during operation. ing.

With the above configuration, when the operator depresses the brake pedal, the front wheel brake valve and the rear wheel brake valve are moved according to the amount of movement (stepping amount), and the pressure from the pressure source is reduced to reduce the front wheel brake and the rear wheel. Supply to each of the brakes. At this time, in normal traveling, the pressure of the front wheel brake is higher than that of the rear wheel brake, and the front wheel brake has a strong braking force. During operation, the pressure at this time is set to the same level as the pressure oil supplied to the front wheel brake by the rear wheel brake pressure increasing means. As a result, when the brake pedal is depressed during traveling, a strong braking force is generated on the front wheels and a weak braking force is generated on the rear wheels, and the same strong braking force is generated on the rear wheels as the front wheels during work. Therefore, the rear wheel and the front wheel do not move, so that the reaction force at the time of work can be maintained, and the vehicle can work in a stable state, the excavating force of the work machine increases, and the amount of work increases I do.

In the second invention mainly based on the first invention, the rear wheel brake pressure increasing means includes the front wheel A first brake valve for a rear wheel brake disposed between a pipe connecting the brake valve for the front wheel and the front wheel brake circuit, a pipe connecting the brake valve for the rear wheel and the rear wheel brake circuit, and the brake valve for the rear wheel And a shuttle valve connected to the rear wheel brake first pressure-up valve and connected to the rear wheel brake first booster valve to select one of the front wheel brake valve and the rear wheel brake valve. According to a brake pressure increase command, the pressure oil of the front wheel brake valve is supplied as pressure oil of the rear wheel brake circuit via the rear wheel brake first pressure increase valve and the shuttle valve.

With the above configuration, during operation, high pressure oil generated by the front wheel brake valve is supplied as pressure oil to the rear wheel brake via the first booster valve and the shuttle valve, and high pressure oil generated by the front wheel brake valve is also provided. The oil shuts off the low pressure from the rear wheel brake valve by the shuttle valve. As a result, the high pressure oil generated by the front wheel brake valve reliably acts on the rear wheels with a simple configuration, and increases the braking force of the rear wheels.

In the third invention mainly based on the first invention, the rear wheel brake pressure increasing means is disposed in a pipe connecting the rear wheel brake valve and the rear wheel brake circuit, and the front wheel brake valve and the front wheel brake are arranged. The rear wheel brake second pressure-up valve connected to the pipe connecting the circuit and the force, the pressure is increased, and the brake oil pressure command of the front wheel brake valve is applied to the rear wheel through the rear wheel brake second pressure-up valve according to the brake pressure increase command. It is supplied as pressure oil for the brake circuit o

With the above configuration, similarly to the second invention, the high pressure oil generated by the front wheel brake valve acts on the rear wheel brake via the second pressure increasing valve. Thus, with a configuration even simpler than in the second invention, it also reliably acts on the rear wheel, and increases the braking force of the rear wheel.

According to a fourth aspect of the invention, which is based on any one of the first to third aspects, the transmission of the operating force from the brake pedal to the rear wheel brake valve is performed by a pilot having a strength corresponding to the operation amount of the brake pedal. Pressure or a link connecting the brake pedal to the rear wheel brake valve.

With the above configuration, in the case of pilot pressure, the master cylinder attached to the brake pedal and the brake valve for the rear wheel can be connected by piping, which simplifies the configuration. You. In addition, by using the boost, a small brake pedal operation force can be used to operate a large rear wheel brake valve. In particular, in the case of industrial vehicles that often require a large braking force of the rear wheel brake due to the stroke end of the operation amount of the brake pedal during work, the operating force is lighter and the effect is greater. In the case of a link, since the brake valve is mechanically connected to the brake pedal, the operation of the brake pedal is reliably transmitted to the brake valve, and the brake valve is often used for industrial vehicles that frequently apply braking force. The responsiveness and drivability are improved.

According to a fifth aspect of the invention, which is based on any one of the first to third aspects, a brake lock means is provided which is locked in a state where the front wheel brake valve and the rear wheel brake valve are operated during operation.

With the above configuration, the work can be performed while the rear wheel braking force is reliably increased during the work, and the vehicle can be stably worked without moving during the work, and the workability is improved and the work amount is increased. .

In the sixth invention, the vehicle is stopped, digging, loading, and the like are performed by the mounted work implement, and the vehicle is driven and operated by the front wheel brake having a strong braking force and the rear wheel brake having a weak braking force. In a traveling brake control device for an industrial vehicle that brakes a vehicle, a brake pedal that outputs a pilot pressure having a strength corresponding to the operation amount, and operates in response to the pilot pressure and operates according to the pilot pressure strength. A variable pressure reducing valve for a rear wheel brake, which reduces the pressure oil of a pressure source and supplies the pressure to the rear wheel brake, and operates in conjunction with the variable pressure reducing valve for the rear wheel brake, thereby controlling the pressure supplied to the rear wheel brake. And a front wheel brake valve for supplying pressure oil to the front wheel brake. The variable pressure reducing valve for rear wheel brake supplies low pressure oil to be supplied to the rear wheel brake during operation. The pressure has been reduced to the same strength as the high pressure oil supplied to the front wheel brakes. With this configuration, during operation, the rear wheel brake receives the same pressure as the pressure oil supplied to the front wheel brake by the variable pressure reducing valve for the rear wheel brake. As a result, similarly to the first invention, a strong braking force is generated on the front wheels and a weak braking force is generated on the rear wheels during traveling, and the same strong braking force is generated on the rear wheels as the front wheels during work. So The rear wheel and front wheel can maintain the reaction force during the work without moving, and the vehicle can work in a stable state, the excavating power of the work equipment increases, and the amount of work increases .

In the seventh invention mainly based on the sixth invention, there is provided a brake locking means which is locked in a state where the front wheel brake valve and the rear wheel brake variable pressure reducing valve are operated at the time of work.

With the above configuration, at the time of work, the front wheel brake valve and the rear wheel brake variable pressure reducing valve are locked while operating by the brake locking means. As a result, as in the case of the fourth invention, at the time of work, the work can be performed with the rear wheel braking force surely increased, and the vehicle can be stably worked without moving during the work, thereby improving workability. At the same time, the amount of work increases.

In the eighth invention, which is based on the first invention, the second invention, the third invention, or the sixth invention, a shift position sensor attached to a shift means for selecting a stop and a traveling speed of the vehicle, and excavation by a work machine A mode sensor attached to a mode switching means for switching to a working mode for loading or the like or a traveling mode; and a vehicle speed sensor for detecting the speed of the vehicle. A control means that outputs a command to either the rear wheel brake pressure increasing means, the rear wheel brake first pressure increasing valve, the rear wheel brake second pressure increasing valve, or the rear wheel brake variable pressure reducing valve, and the brake opening means. It has a step.

With the above configuration, the mode is switched to the work mode by the mode switching means, and when the vehicle stops during the work, the rear wheel brake receives the same pressure as the pressure oil supplied to the front wheel brake. In this way, during work, the rear wheel brake force and the pressure that is the same strength as the pressure oil supplied to the front wheel brake are automatically received, so there is no force to work while the rear wheel brake is kept low.

The ninth invention, which is mainly based on the first invention, the second invention, the third invention, or the sixth invention, includes a brake lock switch for outputting a command to lock a brake, a rear wheel brake pressure increasing means during operation, Wheel brake first booster valve, rear wheel brake second booster valve Or, a command is output to either the variable pressure reducing valve for the rear wheel brake and the brake locking means.

With the above configuration, the brake lock switch causes the rear wheel brake to receive the same pressure as the pressure oil supplied to the front wheel brake. As a result, the rear wheel brake and the front wheel brake can be automatically set to the same strength during work with a simpler configuration than the eighth invention. In addition, reliability is improved because of the simple structure.

In the first invention of the traveling brake control method for an industrial vehicle according to the present invention, the vehicle is stopped, digging, loading, and the like are performed by a mounted work machine, and a front wheel brake having a strong braking force is compared with a weak braking force. In a traveling brake control method for an industrial vehicle in which a vehicle is braked at the time of traveling and working by a rear wheel brake having a brake, the pressure of the front wheel brake is used as the pressure of the rear wheel brake by a brake pressure increase command at the time of work. The braking force of the rear wheel brake is added.

According to the above method, at the time of work, the braking force of the rear wheel brake is increased by the booster. As a result, the same operation and effect as those of the first, second, and third inventions of the device can be obtained.

In the second invention of the method, the stop and running speed of the vehicle are selected, the vehicle is stopped, and the work such as excavation and loading is performed by the mounted work machine. In a traveling brake control method for an industrial vehicle in which a vehicle is braked during traveling and work by a brake and a rear wheel brake, a shift position sensor attached to a shift means for selecting a stop and traveling speed of the vehicle, and a work machine for excavating. X | Receives signals from the mode sensor attached to the mode switching means for switching to the work mode for loading, etc., or the traveling mode, and the vehicle speed sensor for detecting the speed of the vehicle, and outputs a command to the brake lock means. The front wheel brake and the rear wheel brake are being braked and licked.

By the above method, the rear wheel brake receives the same pressure as the pressure oil supplied to the front wheel brake. As a result, the same operation and effect as those of the eighth and ninth inventions of the device can be obtained. In the third invention mainly based on the second invention of the method, when the operation mode is switched to the work mode or a command is output to the brake opening means, the braking force of the rear wheel brake is increased to perform braking, And it is locked.

According to the above method, the front wheel brake and the rear wheel brake have the same braking force and are locked to the same braking force only by outputting a command to the work mode or the brake locking means. As a result, effects similar to those of the fifth and seventh aspects of the device can be obtained. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an electromagnetic and hydraulic circuit diagram of a traveling brake control device for an industrial vehicle according to a first embodiment of the present invention.

FIG. 2 is an electromagnetic / hydraulic circuit diagram according to a second embodiment of the present invention.

FIG. 3 is an electromagnetic / hydraulic circuit diagram according to a third embodiment of the present invention.

FIG. 4 is an electromagnetic / hydraulic circuit diagram according to a fourth embodiment of the present invention.

FIG. 5 is an electromagnetic / hydraulic circuit diagram according to a fifth embodiment of the present invention.

FIG. 6 is an electromagnetic / hydraulic circuit diagram according to a sixth embodiment of the present invention.

FIG. 7 is a side view showing an example of an industrial vehicle equipped with the traveling brake control device of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment A traveling brake control device and a control method for an industrial vehicle according to a first embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 7, the industrial vehicle 51 equipped with the traveling brake control device of the present invention includes a lower traveling body 52 and an upper revolving body 53. A front wheel 54 and a rear wheel 55 are attached to a front portion and a rear portion of the lower traveling structure 52, respectively, and a work implement 56 is attached to the upper revolving structure 53. Further, the front wheel 54 and the rear wheel 55 are respectively provided with a front wheel brake 19 having a strong braking force and a rear wheel brake 20 having a weak braking force, which will be described later. The industrial vehicle 51 stops running and performs work such as excavation and loading by the work machine 56. At this time, the front wheel 54 and the rear wheel 55 are braked by the front and rear wheel brakes 19, 20 so that the industrial vehicle 51 is working without moving.

The engine 1 mounted on the industrial vehicle 51 drives a hydraulic pump 2 as shown in FIG. The hydraulic oil sucked and discharged from the tank 3 by the hydraulic pump 2 is branched into the pipeline 4a and the pipelines 4a and 4b, the input port 1 la of the front wheel brake valve 1 1 and the rear wheel It is led to the input port 12a of the brake valve 12 respectively. Each of the pipelines 4a and 4b has an accumulator 5a and 5b for accumulating the pressure oil and a pressure oil accumulated in each accumulator 5a and 5b flowing back to the hydraulic pump 2. Prevent Check valves 7a and 7b are provided respectively. In addition, the pipeline 4 is provided with a relief valve 9 that discharges the pressure oil to the tank 3 when the oil pressure in each of the accumulators 5a and 5b exceeds a set value.

The front wheel brake valve 11 has an input port 11a, a tank port 11b, and an output port 11c. Input port 1 1a to line 4a, tank port 1 lb to tank 3, output port 1 1c through line 21 and line 21a, input of front wheel hydraulic booster 17 Connected to end 17a. The rear wheel brake valve 12 has an input port 12a, a tank port 12b, and an output port 12c. Input port 1 2a is connected to line 4b, tank port 1 2b is connected to tank 3, and output port 1 2c is connected to line 1 22 to the first input port 13a of shuttle valve 13. ing.

The shuttle valve 13 has a first input port 13a, a second input port 13b, and an output port 13c. The first input port 13a is connected to the output port 12c of the rear wheel brake valve 12 through line 22 and the output port 13c is connected to the rear wheel hydraulic booster through line 22a. 8 input terminals are connected to 18a. The output end 18 b of the rear wheel hydraulic booster 18 is connected to the rear wheel brake carrier 20 through a pipeline 24. The output end 17 b of the front wheel hydraulic booster 17 is also connected to the front wheel brake caliber 19 through a conduit 23.

The rear wheel brake valve 12 is held in the A position by the spring 12 d, and the first pressure receiving part This is a pilot pressure switching type two-position valve that switches to the Β position when pilot pressure is input to 1 2 e or the second pressure receiving section 12 ί. The first pressure receiving section 12 e is connected to the output end 26 a of the master cylinder 26 connected to the brake pedal 25 through a pipe 27. When the brake pedal 25 is depressed, the pilot pressure corresponding to this depressing force (operating amount) is input to the first pressure receiving section 12 e, and the main spool of the rear wheel brake valve 12 moves. .

The second pressure receiving section 12 ί is connected to an output port 15 c of the brake lock valve 15 through a pipe 28. When the brake lock valve 15 switches from the G position to the Η position, the pilot pressure is input from the pilot pump 2a to the second pressure receiving portion 12f.

Further, the rear wheel brake valve 12 is provided with a pressure reducing valve 32 between the input port 12a and the output port 12c at the position B. The pressure reducing valve 32 reduces the output pressure Pr with respect to the input pressure Pa from 0 to a maximum P2 according to the amount of movement of the main spool of the rear wheel brake valve 12.

The front wheel brake valve 11 is connected to the rear wheel brake valve 12 via a spring 12d in a tandem manner. Normally, a spring 11d fixed at one end is held at the C position. I have. When the pilot pressure is input to the first pressure receiving part 12 e or the second pressure receiving part 12 f of the rear wheel brake valve 12 during braking operation, the brake pressure becomes exactly the same as the rear wheel brake valve 12. Interlocks and switches to the D position.

Further, the front wheel brake valve 11 is provided with a pressure reducing valve 31 between the input port 11a and the output port 11c at the position D. The pressure reducing valve 31 reduces the output pressure P f with respect to the input pressure Pa from 0 to a maximum P 1 according to the amount of movement of the main spool of the rear wheel brake valve 12. Here, the reduced output pressures P 1 and P 2 are set so that P 1> P 2. In this embodiment, the front and rear wheel brake valves 11 and 12 are independently connected to the master cylinder 26, respectively, in which the front wheel brake valve 11 and the rear wheel brake valve 12 are connected. It may be operated by receiving pilot pressure. Between the input terminal 17a of the hydraulic booster 17 for the front wheel and the input terminal 18a of the hydraulic booster 18 for the rear wheel, a first booster valve 14 for the rear wheel brake is provided via a shuttle valve 13. It is interposed. Rear wheel brake first booster valve 14 has input port 14a, tank port

It has 14 b and output port 14 c. The input port 14a is connected to the output port 11c of the front-wheel brake valve 11 through line 21, the tank port 14b is connected to tank 3 and the output port 14c is connected to the shuttle valve through line 22b. 13 are connected to the second input port 13b. The rear wheel brake pressure increasing means of the present embodiment includes a rear wheel brake first pressure increasing valve 14 and a shuttle valve 13.

One end of the rear wheel brake first booster valve 14 is held at the E position by a spring 14 e at one end, and switches to the F position when the receiving part 14 d at the other end is energized, and is a solenoid-operated two-position valve. is there. By ON-operating the brake lock switch 41 (hereinafter referred to as brake lock sw 41) which is a brake lock means, a current is supplied from the power supply 47 to the receiving unit 14d.

Brake valve 15 is input port 15a, tank port 15b, output port

Has 15c. The input port 15a is connected to the pilot pump 2a, the tank port 15b is connected to the tank 3, and the output port 15c is connected to the second pressure receiving section 12f of the rear wheel brake valve 12 through the line 28. Have been. The brake lock valve 15 is an electromagnetic switching type two-position valve whose one end is held at the G position by a spring 15 e and is switched to the H position when the receiving part 15 d at the other end is energized. By operating the brake lock sw 41 ON, current is supplied from the power supply 47 to the receiver 15d. The operation unit 45 of the industrial vehicle 51 includes a mode switch 42 (hereinafter referred to as mode switch sw 42) as mode switching means for switching between the traveling mode T and the work mode W, and a shift switch for switching the vehicle speed. A shifter switch 43 (hereinafter referred to as a shifter sw43) is provided. The signals from the switches 42 and 43 are input to a TZM controller 44 as control means.

Next, the operation of the present embodiment, that is, the braking of the industrial vehicle 51 during traveling and the braking during work will be described with reference to FIG. First, when the brake pedal 25 is depressed during traveling, the input end 26a of the master cylinder 26 moves, and the hydraulic pressure at the output end 26b of the master cylinder 26 rises. This pressure acts as pilot pressure on the first pressure receiving portion 12 e of the rear wheel brake valve 12 through the line 27, and switches the rear wheel brake valve 12 from the A position to the B position. Accumre—Pressure oil (pressure = P a) accumulated in evening 5 b passes through line 4 b ′, rear wheel brake valve 12, line 22, shuttle valve 13, line 22 a It flows to the input end 18a of the rear wheel hydraulic booster 18. The hydraulic pressure acting on the input terminal 18a changes from 0 to the maximum P2 by the depression force of the brake pedal 25. Due to the boosting action (magnification-) of the hydraulic booster 18 on this hydraulic pressure, a hydraulic pressure ranging from 0 to a maximum αΧΡ2 is generated at the output end 18b, and this hydraulic oil is passed through the pipeline 24. The wheel brake carrier 20 guides the rear wheel to brake.

At this time, since the front wheel brake valve 11 is interlocked with the rear wheel brake valve 12, the position is switched from the position C to the position D. Then, the pressure oil (pressure = P a) accumulated in the accumulator 5a passes through the line 4a, the front wheel brake valve 11, the lines 21 and 21a, and is then input to the front wheel hydraulic booster 1m. Flow to end 17a. The hydraulic pressure acting on the input 17a varies from 0 to the maximum P1. A hydraulic pressure of 0 to a maximum XP 1 is generated at the output terminal 17 b by the boosting action (magnification =) of the hydraulic booster 17 against this hydraulic pressure, and this hydraulic oil is passed through the pipeline 23 to brake the front wheels. The vehicle is guided by the carrier 19 and the front wheels are braked.

Here, the maximum hydraulic pressure P1 acting on the input terminal 17a of the front wheel hydraulic booster 17 is set to be larger than the maximum hydraulic pressure P2 acting on the input terminal 18a of the rear wheel hydraulic booster 18 (usually PI = 1.5 X P2), the front wheel braking force is greater than the rear wheel braking force, and the well-balanced and safe braking of the entire vehicle can be performed without locking the rear wheels 55. it can.

Next, when the brake block sw41 is turned on during work, the receiving portion 15d of the brake block valve 15 is energized, and the brake block valve 15 switches from the G position to the H position. Then, the pressure oil of pilot pump 2a flows through pipe 28 to the rear wheel. Acts on the second receiver 12 f of the brake valve 12 for the rear wheel, and the brake valve 12 for the rear wheel switches from the A position to the B position. At the same time, the front wheel brake valve 11 switches from position C to position D. Also, power is supplied to the receiving portion 14 d of the rear wheel brake first pressure increasing valve 14, and the rear wheel brake first pressure increasing valve 14 switches from the E position to the F position.

As a result, the pressure oil accumulated in the accumulator 5b flows to the input end 18a of the rear wheel hydraulic booster 18 as described above. On the other hand, the hydraulic oil accumulated in the accumulator 5a flows to the input end 17a of the front-wheel hydraulic booster 17 as described above, and at the same time, from the pipe 21 to the rear-wheel brake first booster valve 14, the pipe The flow also flows to the input end 18a of the rear wheel hydraulic booster 18 through 22 b, the chateau nore valve 13 and the pipeline 22a. For this reason, the same oil pressure varying from 0 to the maximum P 1 acts on the input terminal 17 a of the front wheel hydraulic booster 17 and the input terminal 18 a of the rear wheel hydraulic booster 18. Due to the boosting action of each hydraulic booster 17, 18 (magnification = α) to this hydraulic pressure, the output terminals 17 b, 18 b of the hydraulic boosters 17, 18 have 0 to maximum a XPI. Hydraulic pressure is generated. This hydraulic pressure is guided to each brake caliper 19, 20 through each of the pipelines 23, 24, and the front wheel 54 and the rear wheel 55 are braked by the same braking force. Therefore, it is possible to work in a stable state of the vehicle body.

Next, a second embodiment of the present invention will be described with reference to FIG. The same components as in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the first embodiment, the shuttle valve 13 is used, but in the second embodiment, as shown in FIG. 2, the chateau nore valve 13 is omitted, and the first booster valve 14 for the rear wheel brake is connected to the second brake for the rear wheel. This is replaced with a booster valve 14B. That is, the rear wheel brake pressure increasing means in this embodiment is the rear wheel brake second pressure increasing valve i 4 B.

The rear wheel brake second pressure increasing valve 14B has a first input port 14f, a second manpower port 14g, and an output port 14h. The first input port 14 f is connected to the output port 11 c of the front wheel brake valve 11 through line 21, and the second input port 14 g is connected to the rear wheel brake valve 12 through line 22. The output port 12c and the output port 14h are connected to the input 18a of the rear wheel hydraulic booster 18 through line 22a. ing. One end of the rear wheel brake second booster valve 14B is held at the I position by a spring 14i, and is switched to the J position when the receiving part 14j at the other end is energized. is there. When the brake lock sw 41 is turned ON, current is supplied to the receiver 14 j.

The operation of this embodiment will be described with reference to FIG.

For braking during traveling, the hydraulic oil from the rear wheel brake valve 12 is used to supply the second input port 14 g of the rear wheel brake second booster valve 14 B, the output port 14 g, the output port 14 h, and the pipeline 22 After passing through a, it flows to the input end 18a of the rear wheel hydraulic booster 18. Except for this operation, the operation is the same as that of the first embodiment, and the braking of the front wheels 54 and the rear wheels 55 is completely the same as that of the first embodiment.

For braking during operation, the rear brake second booster valve 14 B is switched from the I position to the J position by turning on the brake lock sw 41, and the hydraulic oil from the front wheel brake valve 11 is released. Wheel brake second booster valve 14 B 1st input boat 14 f, output port 14 h, pipe 22 a, pass through to rear wheel hydraulic booster 18 input port 18 a I let it flow. The rest is the same as in the first embodiment, and the braking of the front wheels 54 and the rear wheels 55 is exactly the same as in the first embodiment.

According to this embodiment, in addition to the effects of the first embodiment, the structure is simplified, the reliability is improved, and the cost is reduced.

Next, a third embodiment of the present invention will be described with reference to FIG. The same components as in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the first embodiment, the shuttle valve 13 and the rear wheel brake first pressure increasing valve 14 are used. However, in the present embodiment, the shuttle valve 13 and the rear wheel brake first pressure increasing valve 14 are omitted. The pressure oil from the front wheel brake valve 11 is applied to the input terminal of the front wheel hydraulic booster 17.

In 17a, the pressure oil from the rear wheel brake valve 1 2 is supplied to the input terminal of the rear wheel hydraulic booster 18

18a, and the pressure reducing valve 32 provided in the rear wheel brake valve 12 is replaced with a variable pressure reducing valve 32B.

When no current is supplied to the receiving part 32a of the variable pressure reducing valve 32b for this rear wheel brake In the same manner as the pressure reducing valve 32 of the first embodiment, the output pressure Pr with respect to the input pressure Pa is reduced from 0 to the maximum P2 according to the amount of movement of the main spool of the rear wheel brake valve 12. ing. When the brake lock sw 41, which is the brake lock means, is turned on and the receiving section 32a is energized, the output pressure Pr is reduced from 0 to the maximum PI (same as the front wheel). It has become.

The operation of this embodiment will be described with reference to FIG.

For braking during traveling, hydraulic oil from the front wheel brake valve 11 is applied to the input terminal 17a of the front wheel hydraulic booster 17 and hydraulic oil from the rear wheel brake valve 12 is directly applied to the rear wheel hydraulic pressure. It flows to the input terminal 18a of the booster 18 respectively. Except for this operation, the operation is the same as that of the first embodiment, and the braking of the front wheels 54 and the rear wheels 55 is completely the same as that of the first embodiment.

For braking during work, the ON operation of the brake lock sw 41 energizes the receiving part 32 a of the variable pressure reducing valve 32 B, and the variable pressure reducing valve 32 B outputs the output pressure of the rear wheel brake valve 12. The decompression is reduced from 0 to the maximum PI from 0 to make it the same as the braking force of the front wheels 54. The same as in the first embodiment except that the pressure oil from the rear wheel brake valve 12 flows directly to the input end 18a of the rear wheel hydraulic booster 18 and brakes the front wheel 54 and the rear wheel 55. Is exactly the same as in the first embodiment.

According to the present embodiment, in addition to the effects of the first embodiment, the structure is further simplified, the reliability is improved, and the cost is reduced.

Next, a fourth embodiment of the present invention will be described with reference to FIG. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In this embodiment, all the hydraulic pressures of the main circuit are set to α times (= multiplication of the hydraulic boosters 17 and 18) in the first embodiment, and the hydraulic booster 17 for the front wheels and the hydraulic pressure for the rear wheels are set. Buses 18 are omitted. The pressure oil from the front wheel brake valve 11 Α and the rear wheel brake valve 12 直接 is directly led to each brake carrier 19, 20. That is, the set pressure of the relief valve 9A is set to α times the set pressure Pa of the relief valve 9 of the first embodiment.

The pressure reducing valve 31A provided on the front wheel brake valve 11 The output pressure P f with respect to Pa is reduced from 0 to the maximum XP 1 according to the amount of movement of the main spool of the rear wheel brake valve 12 A. The pressure reducing valve 32 A provided on the rear wheel brake valve 12 A is configured to output the output pressure Pr with respect to the input pressure << XP a in accordance with the movement amount of the main spool of the rear wheel brake valve 12 A. The pressure is reduced from 0 to a maximum α Χ Ρ2.

In addition, hydraulic pump 2 mm, accumulators 5 A and 5 B, front wheel brake valve 11 A, relief valve 9 A, rear wheel brake valve 12 A, shuttle valve 13 A, rear wheel brake first booster The valve 14 A is a high-pressure type, and the functions are the hydraulic pump 2 of the first embodiment, the accumulators 5 a and 5 b, the brake valve 11 for the front wheels, the brake valve 12 for the rear wheels, and the shuttle valve 1 3. The description is omitted because it is the same as the rear wheel brake first booster valve 14, respectively.

In this embodiment, the hydraulic fluid from the front wheel brake valve 11A and the rear wheel brake valve 12A is applied to the front wheel brake carrier 19 and the rear wheel brake carrier 20, respectively. Except for direct guidance, the operation is the same as that of the first embodiment, and the control of the front wheels 54 and the rear wheels 55 is exactly the same as that of the first embodiment.

According to this embodiment, in addition to the effects of the first embodiment, the structure is further simplified, the reliability is improved, and the cost is reduced.

A fifth embodiment of the present invention will be described with reference to FIG. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In this embodiment, the brake lock sw41 of the first embodiment is omitted, and the work mode W of the mode switching sw42 includes a brake lock function. When the mode switch sw42 is in the work mode W and the shifter sw43 is in the neutral N, the W signal is attached to the shifter sw43 by the mode sensor attached to the mode switch sw42. The N signal is input to the T / M controller 44 A by the shift position sensor. Then, the brake lock signal B is output from the TZM controller 44A to the receiving part 15d of the brake lock valve 15 and the receiving part 14d of the rear brake first booster valve 14. You. If the brakes are opened while the work mode W signal and shifter N signal are input while driving, sudden braking may occur. To prevent this, a pickup 46, which is a vehicle speed sensor, is provided. As a result, the vehicle speed is detected, and the brake lock B signal is output from the TZM controller 44A only when the vehicle speed 0 signal (vehicle speed = 0) is input to the T / M controller 44A. . The other configuration is the same as that of the first embodiment, and the braking of the front wheels 54 and the rear wheels 55 is exactly the same as that of the first embodiment.

According to the present embodiment, in addition to the effects of the first embodiment, it is possible to avoid troublesome operation of the brake lock sw41 and forgetting to insert the brake lock sw41, thereby improving the drivability. An embodiment will be described with reference to FIG. In the first to fifth embodiments, when the brake pedal 25 is depressed, a pilot pressure corresponding to the depressing force is input to the first pressure receiving portion 12e, and the main spool of the brake valve 12 moves. It has become. In this embodiment, the brake pedal 25 A and the brake valve 12 are connected via a link 27 A. When the brake pedal 25 A is depressed, the main spool of the brake valve 12 moves according to the amount of depression, and the output pressure Pr of the brake valve 12 is reduced. According to the present embodiment, since the brake valve 12 is mechanically connected to the brake pedal 25 A through the link 27 A, the operation of the brake pedal 25 A is reliably performed. As well as responsiveness and driving performance.

As a seventh embodiment, the pressure source of the main circuit can be changed from hydraulic pressure to pneumatic pressure. In this case, all the devices in the main circuit change from hydraulic to pneumatic, but the operation is the same as in the first embodiment, and the braking of the front wheels 54 and the rear wheels 55 is exactly the same as in the first embodiment. The circuit diagram of the present embodiment is omitted because only the main circuit in FIG. 1 is changed from hydraulic pressure to hydraulic pressure.

According to this embodiment, in addition to the effects of the first embodiment, handling and maintenance of the device are easy because the pressure medium is air. In the second to seventh embodiments, it is natural that various traveling brake control devices can be configured by appropriately combining these embodiments. Industrial applicability

INDUSTRIAL APPLICABILITY The present invention is useful as various traveling brake control devices and a control method thereof that can safely operate even when braking is performed with full brakes when an industrial vehicle is running at a high speed, and can perform stable work by a brake lock operation during work. .

Claims

The scope of the claims

1. Stop the vehicle, perform work such as excavation and loading with the mounted work machine, and brake the vehicle during traveling and work with the front wheel brake having strong braking force and the rear wheel brake having weak braking force. In a traveling brake control device for an industrial vehicle, the pressure oil of the pressure source is reduced according to the operating force of the brake pedal (25), and the rear-wheel brake valve (12) is connected to the rear-wheel brake (12). It operates in conjunction with the rear wheel brake valve, and is higher than the pressure supplied to the rear wheel brakes. The front wheel brake valve (11) supplies pressure oil to the front wheel brakes. The running brake control for industrial vehicles is provided with a rear wheel brake pressure increasing means for supplying high pressure oil to be supplied as rear wheel brake pressure oil.

2. The rear wheel brake pressure increasing means is provided between a pipe connecting the front wheel brake valve (11) and the front wheel brake circuit, and a pipe connecting the rear wheel brake valve (12) and the rear wheel brake circuit. A rear wheel brake first pressure increasing valve (14), which is disposed in a pipe connecting the rear wheel brake valve and the rear wheel brake circuit, and connected to the rear wheel brake first pressure increasing valve; The front-wheel brake valve is composed of a rear-wheel brake valve and a shuttle valve (13) for selecting either one of the pressure oils. 2. The brake control device according to claim 1, wherein pressure oil of the front wheel brake valve is supplied as pressure oil of the rear wheel brake circuit via a shuttle valve.

3. The rear wheel brake booster is disposed in a pipe connecting the rear wheel brake valve (12) and the rear wheel brake circuit, and connects the front wheel brake valve (11) and the front wheel brake circuit. And a rear wheel brake second booster valve (14B) connected to the connecting pipe. The brake oil boost command passes through the rear wheel brake second booster valve to supply the pressure oil of the front wheel brake valve to the rear wheel. 2. The brake control device according to claim 1, wherein the brake control device is supplied as pressure oil for a brake circuit.

4. The transmission of the operating force from the brake pedal (25) to the rear wheel brake valve (12) is performed by a pilot pressure of a strength corresponding to the operation amount of the brake pedal, or by the brake pedal and the rear wheel The brake control device according to claim 1, 2, or 3, characterized by a link (27A) connecting the brake valve and the brake valve.

5. A brake opening means (15) for operating the front wheel brake valve (11) and the rear wheel brake valve (12) during operation. Brake control device according to range 1, 2, or 3.

6. Stop the vehicle, perform work such as digging and loading with the mounted work machine, and brake the vehicle during traveling and work with the front wheel brake having strong braking force and the rear wheel brake having weak braking force. A brake pedal (25) that outputs a pilot pressure of a strength corresponding to the operation amount, and operates in response to the pilot pressure, and operates in response to the pilot pressure. A variable pressure reducing valve for a rear wheel brake (32B) that reduces the pressure oil of the source and supplies it to the rear wheel brake, and operates in conjunction with the variable pressure reducing valve for the rear wheel brake to supply the rear wheel brake. A front-wheel brake valve (11) for supplying pressure oil higher than the pressure to the front wheel brake, and the variable pressure-reducing valve for rear wheel brake supplies low pressure oil to be supplied to the rear wheel brake during operation. Running shake Ichiki control system for industrial vehicle, characterized in a decompression child to a pressure of as strong as the high pressure oil supplied to the wheel brake.

7. A brake lock means (15), which is locked when the front wheel brake valve (11) and the rear wheel brake variable pressure reducing valve (32B) are operated at the time of work. 6. The travel brake control device for an industrial vehicle according to 6.

8. A shift position sensor attached to the shift means (43) for selecting the stop and traveling speed of the vehicle, and a mode switching means (42) for switching to the work mode in which excavation, loading, etc. are performed by the work machine, or the traveling mode And a vehicle speed sensor (46) for detecting the speed of the vehicle, and

At the time of work, the rear wheel brake pressure increasing means, the rear wheel brake first pressure increasing valve (14), the rear wheel brake second pressure increasing valve (14B), or the rear wheel brake variable pressure reducing valve (32B The traveling brake control of an industrial vehicle according to any one of claims 1, 2, 3, and 6, further comprising a control means (44A) for outputting a command to any one of the brake lock means (15) and the brake lock means (15). apparatus.

9. Equipped with a brake opening switch (41) that outputs a command to release the brake. During work, the rear wheel brake booster, the rear wheel brake first booster (14), and the rear wheel brake second booster (14B) Or outputting a command to one of the variable pressure reducing valve for rear wheel brake (32B) and the brake opening means (15). A traveling brake control device for vehicles.

10. Stop the vehicle, perform work such as excavation and loading with the mounted work machine, and use the front wheel brake with strong braking force and the rear wheel brake with weak braking force to move the vehicle during running and work. In the method for controlling the traveling brake of an industrial vehicle to be braked, at the time of work, the pressure of the front wheel brake is set as the pressure of the rear wheel brake, and the braking force of the rear wheel brake is increased by a brake pressure increase command. A method of controlling the traveling brake of an industrial vehicle.

1 1. Select the stop and running speed of the vehicle, stop the vehicle, and perform work such as excavation and loading with the mounted work machine, switch to the work mode or the run mode, and set the front and rear wheel brakes. In the traveling brake control method for an industrial vehicle, the vehicle is braked during traveling and work by: The shift position sensor attached to the shift means (43) for selecting the stopping and running speed of the vehicle, and the mode switching means (42) for switching to the work mode for excavation, loading, etc. by the work machine, or to the running mode It receives signals from the attached mode sensor and a vehicle speed sensor (46) that detects the speed of the vehicle, and outputs a command to the brake lock means (15) to brake the front wheel brake and the rear wheel brake, and to lock the vehicle. A method for controlling the running brake of an industrial vehicle.

12. When the operation mode is switched to the work mode or a command is output to the brake locking means (15), the braking force of the rear wheel brake is increased to perform braking and lock. Range 11. The method for controlling a traveling brake of an industrial vehicle according to item 1.