KR20160119486A - Hydraulic brake system - Google Patents

Abstract

The present invention relates to a hydraulic brake system. The hydraulic brake system, according to the present invention, comprises: an actuator which is operated by working fluid to generate braking force; a work line which supplies the working fluid to the actuator; a moving line which has a flow path independent from the work line and supplies the working fluid to the actuator; a flow conversion valve which selectively supplies the working fluid supplied from a hydraulic pump to the work line and the moving line; and a decompression valve which is formed on the moving line and reduces the pressure of the moving line to allow the moving line to have a lower pressure than the work line. Therefore, the present invention supplies the working fluid having a different pressure according to the operation type of a construction machine to the actuator.

Description

HYDRAULIC BRAKE SYSTEM [0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a hydraulic brake apparatus which is operated by operating oil to generate a braking force.

Wheel type construction machines such as wheel type excavators and wheel loaders are equipped with a traveling wheel for changing the working position and driving the road. Further, the construction machine has a brake for braking and releasing the brake. The brakes provided in the construction machine are generally hydraulic brakes, which are actuated by hydraulic oil to brak and release the wheels.

On the other hand, the operation of the construction machine can be divided into a work operation and a running operation. The operation of the work means various operations of processing a workpiece by using a working machine such as digging earth, sand or loading it on a vehicle by using a working machine provided in the construction machine. Driving operation means that the construction machine drives the wheel to move from one point to another, and in particular includes the construction machine running on the road.

The work operation is generally performed with the wheel braked and stopped by the brake. When the braking force of the brakes is weak, for example, during excavation work, the main body of the construction machine can be pulled toward the working machine by the load of the workpiece. Therefore, it is preferable that the braking force of the brake is sufficiently large for stable operation. On the other hand, if the braking force of the brake is too high when the construction machine suddenly runs, the construction machine may be turned over due to the nature of the construction machine in which the center of gravity is high and the heavy working machine is attached to the front of the main body. Therefore, it is preferable that the braking force of the brake is sufficiently small so that the construction machine in operation can be stopped for the stability of the running of the construction machine, but the construction machine is not turned on at the time of sudden stop.

However, in the conventional hydraulic brake apparatus, since the hydraulic pressure supplied to the brake actuator is fixed, the operating oil supplied to the brake actuator is set to have a pressure suitable for braking at the time of traveling and a pressure intermediate to a pressure suitable for braking at work do. Therefore, there is a problem that the construction machine can not be stably stopped at the time of the operation, and there is still a concern that the braking operation may be conducted during the braking operation.

KR 10-1997-0040698 A

SUMMARY OF THE INVENTION It is an object of the present invention to provide a hydraulic brake device capable of supplying hydraulic fluid having different pressures to an actuator of a brake in accordance with the type of operation of a construction machine.

In order to solve the above-described problems, the present invention provides an engine control apparatus comprising: an actuator operated by operating oil to generate a braking force; An operation line for supplying operating fluid to the actuator; A traveling line having a flow path that is independent of the working line and for supplying operating fluid to the actuator; A flow path switching valve operating between a first position for supplying the hydraulic fluid supplied from the hydraulic pump to the traveling line and a second position for supplying the working line; And a pressure reducing valve provided on the traveling line and reducing the pressure of the traveling line such that the traveling line has a lower pressure than the working line.

The flow path switching valve may be a solenoid valve.

The pressure reducing valve may be a relief valve that opens when the pressure of the traveling line becomes equal to or higher than a preset pressure and drains a part of the working fluid of the traveling line.

The apparatus may further include a mode selection unit for switching the position of the flow path switching valve.

Further, a work machine operation unit sensor that detects the operation of the work machine operation unit; A travel control unit sensor for sensing an operation of the travel control unit; And a control unit that receives a signal from the working machine operation unit sensor and the traveling operation unit sensor and switches the position of the flow switching valve so that the working oil is supplied to the operation line when it is determined that the working machine operation unit is operated, And a control unit for switching the position of the flow path switching valve so that the operating fluid is supplied to the traveling line.

A brake step-up selector 78 for switching the flow path switching valve 40 to the second position 44 when it is turned on and switching the flow path switching valve 40 to the first position 42 when the flow path switching valve 40 is turned off, As shown in FIG.

According to an embodiment of the present invention, since the operating fluid is supplied to the brake actuator through any one of the working line and the traveling line having lower pressure than the working line, the braking force is increased at the time of operation and the braking force is reduced at the time of operation, The stability is improved at the same time.

According to an embodiment of the present invention, the position of the channel switching valve is automatically switched when the operation unit operation unit or the travel operation unit is detected by the operation unit operation sensor and the travel operation unit sensor, So that it is possible to prevent an accident that may be caused by erroneous operation of the flow path switching valve.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram showing the overall configuration of a hydraulic brake device according to an embodiment of the present invention; FIG.
2 is a diagram showing a relationship between a control unit and a flow path switching valve in a hydraulic brake apparatus according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to designate the same or similar components throughout the drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

FIG. 1 is a diagram showing the overall configuration of a hydraulic brake apparatus according to an embodiment of the present invention, and FIG. 2 is a diagram showing the relationship between a control unit and a flow path switching valve in a hydraulic brake apparatus according to an embodiment of the present invention to be.

1, a hydraulic braking device according to an embodiment of the present invention includes a front wheel actuator 22, a working line 86, a traveling line 85, a flow path switching valve 40, and a pressure reducing valve 50 do. Further, the hydraulic braking device according to the embodiment of the present invention may further include a rear wheel actuator 24, hydraulic oil supply lines 82 and 84, and a brake valve 30.

The front wheel actuator 22 is provided in the front wheel brake and the rear wheel actuator 24 is provided in the rear wheel brake. The front wheel actuator 22 and the rear wheel actuator 24 are actuated by operating oil to brake the front wheels and the rear wheels, respectively. Although the front wheel and rear wheel actuators 22 and 24 are shown as hydraulic cylinders in the present embodiment, the types of the front wheel and rear wheel actuators 22 and 24 can be changed depending on the type of the brakes. In the present description, supplying hydraulic oil to the brake means supplying hydraulic oil to the actuator of the brake, and operation of the brake means that the actuator of the brake is actuated by the hydraulic oil so that the brake generates the braking force.

The hydraulic pumps 12 and 14 may include a first hydraulic pump 12 and a second hydraulic pump 14. The first hydraulic pump 12 and the second hydraulic pump 14 supply the hydraulic fluid to the front wheel actuator 22 and the rear wheel actuator 24, respectively. The pressures of the hydraulic fluid discharged from the first hydraulic pump 12 and the second hydraulic pump 14 may be different from each other. In this embodiment, two hydraulic pumps 12 and 14 are provided, the hydraulic oil discharged from the first hydraulic pump 12 is supplied to the front wheel actuator 22, and the hydraulic oil discharged from the second hydraulic pump 14 The hydraulic fluid supplied from the hydraulic pump is supplied to the front wheel actuator 22 and the front wheel actuator 22 via the front wheel actuator 22 and the rear wheel actuator 24, And the rear wheel actuator 24, respectively.

The hydraulic oil supply lines 82 and 84 include a first hydraulic oil supply line 82 and a second hydraulic oil supply line 84. The operating oil discharged from the first hydraulic pump 12 is supplied to the first hydraulic oil supply line 82 and the hydraulic oil discharged from the second hydraulic pump 14 is supplied to the second hydraulic oil supply line 84. The first hydraulic oil supply line 82 connects the first hydraulic pump 12 and the oil line switching valve 40 and the second hydraulic oil supply line 84 connects the second hydraulic pump 14 and the rear wheel actuator 24 Connect. At this time, the first hydraulic oil supply line 82 may be directly connected to the first hydraulic pump 12 and the oil line switching valve 40, or may be connected through another medium, to be.

The brake valve 30 is provided on the hydraulic oil supply lines 82 and 84 so that hydraulic fluid discharged from the hydraulic pumps 12 and 14 is supplied to the actuators 22 and 24 by switching the position by the operation of the brake pedal 60. [ Or the hydraulic fluid is drained from the actuators 22, 24 to the tank side. In other words, the brake valve 60 controls the flow direction of the hydraulic fluid flowing along the hydraulic oil supply lines 82, 84. The brake valve 30 has a first position 32 for draining hydraulic oil from front and rear wheel actuators 22 and 24, a second position 34 for supplying hydraulic oil to the front wheel and rear wheel actuators 22 and 24, Position 36. [0035] The hydraulic oil discharged from the hydraulic pumps 12 and 14 is not supplied to the front and rear wheel actuators 22 and 24 as the brake valve 30 maintains the first position 32 when the user does not step on the brake pedal 60 And the hydraulic fluid in the front and rear wheel actuators 22 and 24 is drained to the tank. When the user depresses the brake pedal 60, the brake valve 30 is switched to the second position 34, so that the operating oil discharged from the hydraulic pumps 12, 14 passes through the brake valve 30, And supplied to the actuators 22 and 24. At this time, the second position 34 of the brake valve 30 is provided with an orifice inside the valve, thereby reducing the flow rate of the hydraulic fluid passing through the brake valve 30. [ When the user depresses the brake pedal 60 deeper, the brake valve 30 is switched to the third position 36 so that the hydraulic oil at the maximum flow rate passes through the brake valve 30. When the user releases his / her foot from the brake pedal 60, the brake valve 30 is returned to the first position 32 so that the operating fluid of the front and rear wheel actuators 22 and 24 is drained to the tank.

The traveling line 85 and the working line 86 have an independent flow path and connect the front wheel actuator 22 and the flow path switching valve 40 to each other. The running line 85 and the working line 86 are supplied with the working oil through the running line 85 and the working line 86 since the running line 85 and the working line 86 have independent flow paths. The supplied hydraulic fluid may have different pressures. The hydraulic fluid is supplied to the front wheel actuator 22 only through one of the traveling line 85 and the working line 86 connected to the first hydraulic oil supply line 82 by the oil line switching valve 40. When the operating fluid is supplied through the traveling line 85 or the working line 86, the front wheel actuator 22 is operated to generate a braking force on the front wheels. The running line 85 is for supplying the hydraulic fluid to the front wheel actuator 22 during the traveling operation of the construction machine and the working line 86 is for supplying the hydraulic oil to the front wheel actuator 22, .

The oil line switching valve 40 selectively connects the first hydraulic oil supply line 82 with the traveling line 85 or the operation line 86. The flow path switching valve 40 is connected to a first position 42 for connecting the first hydraulic oil supply line 82 to the traveling line 85 and a second position 42 for connecting the first hydraulic oil supply line 82 to the working line 86, Position 44. [0035] The flow path switching valve 40 may be a solenoid valve operated by an electrical signal. When the first hydraulic oil supply line 82 is connected to the traveling line 85 or the working line 86 by the hydraulic oil switching valve 40, the hydraulic oil supplied through the first hydraulic oil supply line 82 is supplied to the traveling line 85 Or operation line 86, as shown in FIG. That is, the flow path switching valve 40 selectively supplies the operating fluid supplied from the first hydraulic pump 12 to the traveling line 85 or the working line 86. The user can select the position of the flow path switching valve 40 according to the type of work to be performed through the construction machine. To this end, the hydraulic braking device may be provided with a mode selector 76 which can be operated by the user. The mode selection unit 76 may be configured to select either the traveling mode or the working mode. When the user selects any one of the two modes, it is transmitted to the control unit (70 in FIG. 2). Accordingly, the control unit 70 outputs a control signal to control the position of the flow path switching valve 40.

The pressure reducing valve (50) is provided on the traveling line (85) to reduce the pressure of the operating fluid supplied to the front wheel actuator (22). The pressure reducing valve 50 may be a relief valve that opens when the pressure of the traveling line 85 becomes equal to or higher than a preset pressure and reduces the pressure of the traveling line 85 by draining a part of the working oil of the traveling line 85. Since both the traveling line 85 and the working line 86 are supplied with the working oil from the first working oil supply line 82, the pressure of the working oil supplied to the traveling line 85 is lower than the pressure of the working oil supplied to the working line 86 But the travel line 85 may be provided with the pressure reducing valve 50 so that the travel line 85 can have a lower pressure than the operation line 86. [ The braking force of the brake is proportional to the pressure of the operating oil supplied to the actuator. Therefore, when the operating fluid is supplied to the front wheel actuator 22 through the traveling line 85, the pressure of the operating fluid supplied through the traveling line 85 is smaller than the pressure of the operating fluid supplied through the working line 86, So that a relatively large braking force can be generated when the operating fluid is supplied to the front wheel actuator 22 through the operation line 86. [ Therefore, when the traveling line 85 is set to have a proper pressure for the traveling braking and the working line 86 is set to have a proper pressure for the working braking, The braking force suitable for the braking operation can be generated by supplying the front wheel actuator 22 with the working oil through the working line 86 during the work. In other words, it is possible to provide an appropriate braking force according to the type of operation of the construction machine without changing the discharge pressure of the first hydraulic pump 12.

The rear wheel actuator 24 is operated by operating oil supplied through the second hydraulic oil supply line 84 to generate a braking force on the rear wheels. At this time, the pressure of the hydraulic oil supplied to the rear wheel actuator 24, that is, the pressure of the second hydraulic oil supply line 84, may be larger than the pressure of the traveling line 85 and smaller than the pressure of the working line 86. The braking operation is performed mainly by the front wheel brake when the traveling or working of the construction machine is performed so that the front wheel actuator 22 is selectively supplied with the operating oil through the traveling line 85 or the working line 86, It is possible to simplify the construction of the brake system while improving the work stability and the running stability by supplying the hydraulic fluid directly through the oil passage 84. [ If the hydraulic fluid is selectively supplied to the rear wheel actuator 24 through the traveling line 85 and the working line 86 and the pressure reducing valve 50 is provided on the traveling line 85 in the same manner as the front wheel actuator 22, It is obvious that the running stability and the work stability can be improved even if the configuration of the brake system becomes somewhat complicated.

On the other hand, the construction machine is repeatedly changed over between the work operation and the traveling operation, such as an excavator moving the soil by bucket after loading the soil on the bucket, and emptying the soil from the bucket. Therefore, when the user manually operates the mode selection unit 76 during the operation of the construction machine to switch the flow path switching valve 40, it is troublesome according to the frequent operation of the mode selection unit 76, There is a risk that the construction machine moves during the operation or the construction machine is turned on when the braking operation is performed. Therefore, the hydraulic braking device may include a working machine operation part sensor 72 and a traveling operation part sensor 74 to automatically switch the position of the flow path switching valve 40. [

The operation device sensor 72 senses the operation of the operation device operation unit and outputs it to the control unit 70. The operation unit sensor 74 senses the operation of the operation unit and outputs the operation to the control unit 70. [ The machine operation portion is operated by the user to operate the working machine of the construction machine, and the running operation portion is operated by the user to drive the construction machine. When the control unit 70 determines that the working machine operating unit is operated by the signal received from the working machine operating unit sensor 72, the control unit 70 controls the flow path switching valve 40 to supply the operating fluid to the working line 86 By switching to the second position 44, a large braking force can be generated on the front wheels. When the control unit 70 determines that the travel control unit is operated by the signal received from the travel control unit sensor 74, the control unit 70 controls the flow control valve 40 to supply the hydraulic fluid to the travel line 85 By switching to the first position 42, a relatively small braking force can be generated on the front wheels.

On the other hand, the hydraulic braking device may be provided with a brake step-up selector 78 which can be operated by a user. The brake step-up selector 78 can be configured to enable the user to turn on / off the brake pedal. The brake step-up selector 78 is for the user to arbitrarily raise the braking force of the brake. The ON / OFF state of the brake step-up selector 78 is transmitted to the control unit 70, and the control unit 70 outputs a control signal to control the position of the flow path switching valve 40. When the brake step-up selecting part 78 is turned on, the control part 70 switches the flow path switching valve 40 to the second position 44 regardless of whether the construction machine is in the traveling mode or the working mode so that a large braking force is generated in the front wheel Can be done. Further, the operation signal of the brake step-up selector 78 can be input directly to the oil line switching valve 40 without passing through the control part 70. [ At this time, when the brake step-up selector 78 is turned on, the flow path switching valve 40 is switched to the second position 44, and when the brake step-up selector 78 is turned off, 42). The user can implement a large braking force at any time by turning on the brake step-up selector 78. [

It will be apparent to those skilled in the art that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. . Therefore, the embodiments disclosed in the present invention are not intended to limit the scope of the present invention but to limit the scope of the technical idea of the present invention. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

12, 14: Hydraulic pump 22, 24: Actuator
30: brake valve 40: flow path switching valve
50: Pressure reducing valve 60: Brake pedal
70: control part 72: work machine operation part sensor
74: traveling operation sensor 76: mode selection unit

Claims (6)

An actuator for being operated by the operating oil to generate a braking force;
An operation line for supplying operating fluid to the actuator;
A traveling line having a flow path that is independent of the working line and for supplying operating fluid to the actuator;
A flow path switching valve operating between a first position for supplying the hydraulic fluid supplied from the hydraulic pump to the traveling line and a second position for supplying the working line; And
And a pressure reducing valve provided on the traveling line and reducing the pressure of the traveling line so that the traveling line has a lower pressure than the working line. The method according to claim 1,
Wherein the flow path switching valve is a solenoid valve. The method according to claim 1,
Wherein the pressure reducing valve is a relief valve that opens when the pressure of the traveling line becomes equal to or higher than a preset pressure and drains a part of the working oil of the traveling line. The method according to claim 1,
Further comprising a mode selection unit for switching the position of said flow path switching valve. The method according to claim 1,
A work machine operation unit sensor for detecting an operation of the work machine operation unit;
A travel control unit sensor for sensing an operation of the travel control unit; And
And a control unit that receives a signal from the operating unit sensor and the traveling control unit sensor and switches the position of the flow control valve so that the operating fluid is supplied to the working line when it is determined that the working control unit is operated, Further comprising a control unit for switching the position of the flow path switching valve so that the hydraulic fluid is supplied to the traveling line. The method of claim 1, wherein
The brake pressure increase selector 78 for switching the flow path switching valve 40 to the second position 44 when the switching valve 40 is turned on and switching the flow path switching valve 40 to the first position 42 when the switching valve 40 is turned off, Hydraulic brake device included.

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