JPH0711469U - Vehicle braking system - Google Patents

Abstract

(57) [Summary] [Purpose] Both the service brake mechanism and the parking brake mechanism brake the axle. [Structure] When the brake pedal 79 is depressed, hydraulic pressure is supplied from the brake valve 78 to the first inflow portion 71. The brake piston 63 projects and presses the brake ring 62, and the brake ring 62 comes into pressure contact with the brake disc 61, and the rotation of the axle 49 is stopped. When the parking brake valve 80 is switched by operating the valve lever 81 during parking, the parking brake fluid pressure circuit 53 is cut off and the hydraulic pressure is not supplied to the second inflow portion 72. The urging force of the compression spring 64 causes the brake piston 63 to press the brake ring 62, and the brake ring 62 is brought into pressure contact with the brake disc 61, so that the rotation of the axle 49 is stopped.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a braking device for braking an axle mounted on a large vehicle such as a wheel loader.

[0002]

[Prior art]

 Generally, braking devices for large vehicles such as wheel loaders include a service brake mechanism that drives when a worker steps on a brake pedal during normal vehicle operation, and a parking system that operates when a valve lever is operated during parking. A brake mechanism is provided.

Conventionally, as shown in FIG. 6, a service brake mechanism supplies a wet type disc brake 2 provided on an axle device 1 corresponding to all wheels, and a hydraulic pressure for operating the disc brake 2. And the service brake fluid pressure circuit 3. The disc brake 2 has a disc hub 4 installed in a brake housing 1a and connected to an axle, a brake disc 5 attached to the disc hub 4, and a press contact with the brake disc 5 to prevent rotation of the axle. The brake ring 6 includes a brake ring 6, a brake piston 7 that presses the brake ring 6 in a pressure contact direction, and a spring that biases the brake ring 6 in a separation direction.

The service brake fluid pressure circuit 3 is connected to a piston housing chamber 7 a formed in the brake housing 1 a and supplies hydraulic pressure so that the brake piston 7 moves toward the brake ring 6. The service brake fluid pressure circuit 3 is provided with a brake valve 10 that switches the supply of hydraulic pressure from the pump 8 by operating a pump 8, a regulator valve 9, and a brake pedal 11.

Further, as shown in FIG. 7, the parking brake mechanism provides a parking disc brake 17 provided at a connecting portion between the front wheel axle 15 and the propeller shaft 16 and a hydraulic pressure for operating the disc brake 17. It is composed of a parking brake fluid pressure circuit 18 to be supplied and has a function as an emergency brake. The disc brake 17 for parking includes a rotating disc 19 fixed to the front end of the propeller shaft 16, a brake pad 20 that presses against the rotating disc 19 to stop the rotation of the propeller shaft 16, and the brake. A crank 21 that presses and separates the pad 20 from the rotating disk 19 and a spring chamber 23 that moves a piston rod 22 connected to the crank 21 are provided. A spring 24 for urging the piston rod 22 in a direction in which the brake pad 20 is pressed against the rotating disc 19 is installed in the spring chamber 23.

The parking brake fluid pressure circuit 18 is connected to the head side of the spring chamber 23 and supplies hydraulic pressure to extend the piston rod 22 against the spring 24. The parking brake fluid pressure circuit 18 is provided with a parking brake valve 27 that switches the supply of hydraulic pressure from the pump 25 by operating a pump 25, a regulator valve 26, and a valve lever 28.

In the service brake mechanism, when the brake pedal 11 is not stepped on, the service brake fluid pressure circuit 3 is shut off by the brake valve 10, so that the hydraulic pressure from the pump 8 is not supplied to the brake disc 5. Is open and the axle is rotatable.

On the other hand, in the parking brake mechanism, the oil pressure from the pump 25 is supplied to the spring chamber 23 via the parking brake valve 27, and the oil pressure pushes the piston rod 22 against the spring 24. Therefore, the brake pad 20 is separated from the rotary disc 19, and the propeller shaft 16 is rotatable.

Here, when the brake pedal 11 is stepped on, the service brake fluid pressure circuit 3 is communicated and hydraulic pressure is supplied, and the brake ring 6 pressed by the brake piston 7 is brought into pressure contact with the brake disc 5 and the axle shaft The rotation is stopped.

During parking, the valve lever 28 is operated to switch the parking brake valve 27 to shut off the hydraulic pressure to the spring chamber 23. Then, the piston rod 22 is shortened by the spring 24, the brake pad 20 is pressed against the rotating disc 19, and the rotation of the propeller shaft 16 is stopped.

Further, as shown in FIG. 8, there is an air-over-hydraulic braking device in which a wet type disc brake is provided for each wheel. In this braking device, a service brake fluid pressure circuit 30 and a parking brake fluid pressure circuit 31 are branched by a right brake valve 32, and the compressed air pressure supplied to each fluid pressure circuit is controlled by switching the brake valve 32. It is said that.

The service brake fluid pressure circuit 30 transfers the compressed air pressure from the air compressor from the governor 34 to the air tank 35, to the lower chamber 33 a of the left brake valve 33, and to the lower chamber 32 a of the right brake valve 32. Of the brake valves 32, 33 from the upper chambers 32b, 33b to the double check valve 36, the quick release valve 37, the booster 38 including the chamber 38a and the cylinder 38b, and the hydraulic line from the booster 38 to the booster 38. It consists of a hydraulic line leading to the brake.

The parking brake fluid pressure circuit 31 includes an air line that guides compressed air pressure from the lower chamber 32 a of the right brake valve 32 to the parking brake valve 39, the quick release valve 37, and the spring chamber 40. In FIG. 8, 41 is a safety valve, 42 is a drain cock, 43 is a brake pedal, 44 is an oil tank, and the structure of the disc brake is the same as that described above.

When the brake pedal 43 is not stepped on, the service brake fluid pressure circuit 30 is shut off by the brake valve 32, and the compressed air pressure from the air compressor is not converted into hydraulic pressure in the booster 38. The axle is rotatable as in.

On the other hand, the parking brake fluid pressure circuit 31 is in communication, the compressed air pressure from the air compressor is supplied to the spring chamber 40, and the propeller shaft can rotate as described above.

Here, when the brake pedal 43 on the right side or the left side is depressed, compressed air pressure is supplied to the booster 38, and this compressed air pressure is converted into hydraulic pressure to stop the rotation of the axle.

During parking, the parking brake valve 39 is switched so that compressed air is released from the parking brake valve 39 to the atmosphere and compressed air pressure is not supplied to the spring chamber 40. Then, similarly to the above, the rotation of the propeller shaft is stopped.

Further, in an emergency such as breakage of the service brake fluid pressure circuit 30 and the parking brake fluid pressure circuit 31, the parking brake valve 39 automatically operates and compressed air is supplied from the parking brake valve 39 and the quick release valve 37. Release to the atmosphere and the rotation of the propeller shaft is stopped. When the brake pedal 43 on the left side is depressed, the braking action and the inching action can be performed.

[0019]

[Problems to be solved by the device]

 In the conventional braking device, the parking brake mechanism has a structure for braking the propeller shaft and other thrust shafts, but recently, the parking brake mechanism has a structure for braking the axle shaft according to the ISO standard (international standardization mechanism). Is about to be revised.

Further, in the conventional braking device, since the service brake mechanism brakes the axle and the parking brake mechanism brakes the propulsion shaft, it is necessary to provide the disc brakes 2 and 17 on both the axle and the propulsion shaft. As a result, the number of parts has increased and the cost has increased.

In view of the above, the present invention has an object of providing a vehicle braking device in which both the service brake mechanism and the parking brake mechanism brake the axle and the number of parts is reduced.

[0022]

[Means for Solving the Problems]

 The problem solving means according to the present invention is, as shown in FIG. 1, a brake disc 61 provided on an axle 49, a braking body 63 that is pressed against and separated from the brake disc 61, and a biasing force that biases the braking body 63 in the pressing direction. A body 64, a service brake fluid pressure circuit 52 for supplying a fluid pressure for moving the braking body 63 in a pressure contact direction, and a parking brake fluid pressure circuit 53 for supplying a fluid pressure for moving the braking body 63 in a separating direction. The service brake fluid pressure circuit 52 is provided with a brake valve 78 for controlling the fluid pressure by operating the brake pedal 79, and the parking brake fluid pressure circuit 53 is operated by operating the operating body 81. A parking brake valve 80 is provided.

[0023]

[Action]

 In the above problem solving means, the service valve fluid pressure circuit 52 is normally shut off by the brake valve 78. On the other hand, the parking brake fluid pressure circuit 53 is in communication, and the hydraulic pressure for moving the braking body 63 in the separating direction is supplied. For this reason, the braking body 63 is separated from the brake disc 61 against the biasing body 64, and the axle 49 is rotatable.

Here, when the brake pedal 79 is stepped on, the brake valve 78 is switched, the service brake fluid pressure circuit 52 is communicated, and the hydraulic pressure for moving the braking body 63 in the pressure contact direction is supplied. Then, the braking body 63 comes into pressure contact with the brake disc 61, and the rotation of the axle 49 is stopped.

At the time of parking, the operating body 81 is operated to switch the parking brake valve 80 to shut off the parking brake fluid pressure circuit 53. Then, the biasing force of the biasing body 64 causes the damping body 63 to come into pressure contact with the brake disc 61, and the rotation of the axle 49 is stopped. As described above, the service brake mechanism and the parking brake mechanism both have a structure for braking the axle 49, and the same braking body 63 can be used.

[0026]

【Example】

 (First Embodiment) A braking device for a large vehicle such as a wheel loader according to a first embodiment of the present invention has a structure in which a service brake mechanism and a parking brake mechanism are combined, and front and rear axles are arranged as shown in FIG. Wet type single plate type disc brake 51 provided on an axle device 50 corresponding to wheels at both ends of 49, a service brake fluid pressure circuit 52 for supplying hydraulic pressure for operating the disc brake 51, and a parking brake fluid body. And a pressure circuit 53.

The disc brake 51 is arranged in an axle device main body in which a gear housing 54 and a brake housing 55 are assembled, and is spline-fitted to the disc hub 60, which is spline-fitted to the axle 49. The brake disc 61, a brake ring 62 that presses the brake disc 61 to stop the rotation of the axle 49, a braking body 63 that presses and separates from the brake ring 62, and the braking body 63 in the pressing direction. And a biasing body 64 for biasing. The brake ring 62 is held by an end plate 65 movably supported by the brake housing 55.

The braking body 63 is composed of a ring-shaped brake piston having a flange 63 a, and is movable back and forth into a piston storage chamber 66 having an opening 66 a formed in the brake housing 55 so as to face the brake ring 62. It is distributed.

An O-ring 70 that seals the inside of the piston storage chamber 66 by slidingly contacting the inner and outer peripheral surfaces of the brake piston 63 is arranged near the opening 66 a of the piston storage chamber 66. Further, the piston accommodating chamber 66 is divided into left and right by a flange portion 63a, and the right side thereof is a first inflow portion 71 to which the hydraulic pressure from the service brake fluid pressure circuit 52 is supplied. Further, the left side of the piston storage chamber 66, which is divided by the flange portion 63a, is a second inflow portion 72 to which the hydraulic pressure from the parking brake fluid pressure circuit 53 is supplied. An O-ring 73, which is in sliding contact with the outer peripheral surface of the flange portion 63a, is arranged between the break housing 55 and the outer peripheral surface of the flange portion 63a.

The urging body 64 comprises a plurality of compression springs installed in the first inflow portion 71, and the compression springs are interposed between the brake piston 63 and the wall surface of the piston housing chamber 66. .

The service brake fluid pressure circuit 52 is connected to the opening 71 a of the first inflow portion 71, and the hydraulic pressure is supplied from the pump 76 by operating the pump 76, the regulator valve 77, and the brake pedal 79 as in the conventional case. A brake valve 78 for controlling the engine is provided.

The parking brake fluid pressure circuit 53 is connected to the opening 72 a of the second inflow portion 72, is branched from the service brake fluid pressure circuit 52 on the upstream side of the brake valve 78, and is operated by an operating body (hereinafter, valve lever). ) 81, a parking brake valve 80 for switching the supply of hydraulic pressure from the pump 76 is provided.

In FIG. 1, reference numeral 82 is a sun gear, 83 is a planet gear, 84 is a planet shaft, 85 is a planet carrier, 86 is a wheel hub, and 87 is a wheel hold bolt, which form a final reduction gear. There is.

In the above configuration, when the brake pedal 79 is not stepped on, the service valve fluid pressure circuit 52 is shut off by the brake valve 78, and the hydraulic pressure from the pump 76 is applied from the parking brake fluid pressure circuit 53 to the parking brake valve 80. It is then supplied to the second inflow portion 72 of the piston storage chamber 66. Due to the hydraulic pressure supplied to the second inflow portion 72, the brake piston 63 is housed in the piston storage chamber 66 against the compression spring 64. Therefore, the brake ring 62 is separated from the brake disc 61 so that the axle 49 can rotate.

Here, when the brake pedal 79 is stepped on, the service brake fluid pressure circuit 52 is connected to supply the hydraulic pressure to the first inflow portion 71. Then, the combined force of the oil pressure of the first inflow portion 71 and the urging force of the compression spring 64 overcomes the oil pressure of the second inflow portion 72, causing the brake piston 63 to project from the opening 66 a of the piston storage chamber 66. The rake ring 62 is pressed, the brake ring 62 is pressed against the brake disc 61, and the rotation of the axle 49 is stopped.

During parking, if the valve lever 81 is operated to switch the parking brake valve 80, the parking brake fluid pressure circuit 53 is shut off. Then, the pressure oil in the second inflow portion 72 is discharged to the outside from the parking brake valve 80, the brake piston 62 presses the brake ring 62 by the urging force of the compression spring 64, and the brake ring 62 presses against the brake disc 61. Then, the rotation of the axle 49 is stopped.

As described above, the service brake fluid pressure circuit 52 and the parking brake fluid pressure circuit 53 are connected to the disc brake 51, and the disk brake 51 is operated to brake the axle 49 by controlling the respective hydraulic pressures. That is, both the service brake mechanism and the parking brake mechanism are structured to brake the axle 49, and the same disc brake 51 can be used. Therefore, it is possible to comply with the revised ISO standard, reduce the number of parts, and reduce costs.

Second Embodiment As shown in FIG. 2, the braking device of the second embodiment supplies the service brake fluid pressure circuit 30 that supplies hydraulic pressure to the disc brakes of all wheels and the hydraulic pressure to the disc brakes of the front wheels. And a parking brake fluid pressure circuit 90. It should be noted that the same symbols are given to the same structural members as in the conventional case.

The disc brake in this braking device has the same structure as in the first embodiment. The service brake fluid pressure circuit 30 is connected to the opening 71a of the first inflow portion 71 of the piston storage chamber 66, and the parking brake fluid pressure circuit 90 is connected to the opening 72a of the second inflow portion 72 of the piston storage chamber 66. There is. In the parking brake fluid pressure circuit 90, a booster 91 including a chamber 91a and a cylinder 91b is provided between the parking brake valve 39 and the opening 72a. Other configurations are the same as conventional ones.

FIG. 3 shows the internal structure of the brake valves 32 and 33. 93 is a roller, 94 is a plunger, 95 is a boot, 96 is a stop rubber, 97 is a plate, 98 is a rubber spring, 99 is a piston, and 100 is A valve, 101 is a valve seat, and 102 is a diaphragm.

4 and 5 show the internal structure of the parking brake valve 39. 110 is a valve lever, 111 is a nut, 112 is an exhaust port, 113 is a spring, 114 is a valve shaft, and 115 is a valve. 4 shows a state in which the valve lever 110 is pushed and the parking brake fluid pressure circuit 90 is in communication, and FIG. 5 shows a state in which the valve lever 110 is pulled and the parking brake fluid pressure circuit 90 is cut off. Show.

In the above configuration, when the brake pedal 43 is not stepped on, the service brake fluid pressure circuit 30 is shut off by the brake valves 32 and 33, and the compressed air pressure from the air compressor is boosted by the parking brake fluid pressure circuit 90. Device 91. At this time, the compressed air pressure is converted into hydraulic pressure and supplied to the disc brake as in the first embodiment, so that the axle can rotate.

Here, when the right or left brake pedal 43 is stepped on, the service brake fluid pressure circuit 30 is communicated, compressed air pressure is supplied to the booster 38, and this compressed air pressure is converted to hydraulic pressure. As in one embodiment, the disc brake is supplied to stop the rotation of the axle.

At the time of parking, as shown in FIG. 5, the valve lever 110 is pulled to switch the parking brake valve 39, compressed air is discharged from the exhaust port 112 of the parking brake valve 39 to the atmosphere, and the compressed air pressure is boosted by the booster 91. Not supplied to. Then, the rotation of the axle is stopped as in the first embodiment.

Further, in an emergency such as breakage of the service brake fluid pressure circuit 30 and the parking brake fluid pressure circuit 90, the parking brake valve 39 automatically operates, and the exhaust port 112 of the parking brake valve 39 and the quick release valve 37 are connected. Compressed air is exhausted from the air and the rotation of the axle is stopped.

It should be noted that the present invention is not limited to the above embodiment, and it goes without saying that many modifications and changes can be made to the above embodiment within the scope of the present invention. For example, the disc brake 51 in the first and second embodiments may be a multi-disc type. The disc brake 51 in the first and second embodiments is arranged in front of the final reduction gear (between the differential and the final reduction gear), but after the final reduction gear (from the final reduction gear to the wheels). Up to).

[0047]

[Effect of device]

 As is clear from the above description, according to the present invention, the same brake body can be operated to brake the axle by controlling the fluid pressure from the service brake fluid pressure circuit or the parking brake fluid pressure circuit. That is, the service brake mechanism and the parking brake mechanism both have a structure for braking the axle, and the same brake body can be used. Therefore, the number of parts can be reduced and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a brake line of a braking device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a brake line of a braking device according to a second embodiment.

FIG. 3 is a vertical sectional view of a brake valve.

FIG. 4 is a vertical sectional view of the parking brake valve when the valve lever is pushed.

FIG. 5 is a vertical sectional view of the parking brake valve when the valve lever is pulled.

FIG. 6 is a diagram showing a brake line of a service brake mechanism in a conventional braking device.

FIG. 7 is a diagram showing a brake line of the parking brake mechanism.

FIG. 8 is a diagram showing a brake line of another conventional braking device.

[Explanation of symbols]

 49 Axle 30,52 Service brake fluid pressure circuit 53,90 Parking brake fluid pressure circuit 61 Brake disc 63 Brake element 64 Energizer 32,33,78 Brake valve 43,79 Brake pedal 39,80 Parking brake valve 81,110 Bubble lever

Claims (1)

[Scope of utility model registration request] 1. A brake disc provided on an axle,
A braking body that is pressed against and separated from the brake disc, an urging body that urges the braking body in the pressing direction, a service brake fluid pressure circuit that supplies a fluid pressure that moves the braking body in the pressing direction, and the braking body. And a parking brake fluid pressure circuit for supplying a fluid pressure for moving the vehicle in the separating direction, the service brake fluid pressure circuit is provided with a brake valve for controlling the fluid pressure by operating a brake pedal, and the parking brake fluid pressure circuit is provided. A braking device for a vehicle, wherein a parking brake valve for controlling fluid pressure by operating an operating body is provided in the vehicle.