KR102328900B1 - Hydraulic brake system - Google Patents

Abstract

The present invention relates to a hydraulic brake device. The hydraulic brake device according to the present invention has an actuator operated by hydraulic oil to generate braking force, a work line for supplying hydraulic oil to the actuator, and a flow path independent of the work line, for supplying hydraulic oil to the actuator A travel line, a flow path switching valve for selectively supplying hydraulic oil supplied from the hydraulic pump to the work line or the travel line, and the travel line provided on the travel line so that the travel line has a lower pressure than the work line It includes a pressure reducing valve for reducing the pressure of the

Description

Hydraulic brake system {HYDRAULIC BRAKE SYSTEM}

The present invention relates to a hydraulic brake device operated by hydraulic oil to generate braking force.

A wheel-type construction machine such as a wheel-type excavator and a wheel loader is provided with a driving wheel to change a working position and travel on a road. In addition, in order to brake and release the wheel, the construction machine is provided with a brake. Brakes provided in construction machines are generally hydraulic brakes, which are operated by hydraulic oil to brake and release the brakes.

On the other hand, the operation of the construction machine can be divided into a work operation and a driving operation. The work operation refers to various operations of processing a work object using a work machine, such as digging soil, sand, or the like using a work machine provided in a construction machine or loading it in a vehicle. The 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 a road.

Working motions are usually performed with the wheel stopped by the brake. During a work operation, for example, if the braking force of the brake during the excavation work of the excavator is weak, the main body of the construction machine may be dragged toward the work machine by the load of the work object. Therefore, it is preferable that the braking force of the brake is sufficiently large for stable operation. On the other hand, when a construction machine stops suddenly while driving, if the braking force of the brake is too large, the center of gravity is high and the construction machine may be overturned due to the characteristics of the construction machine, which is attached to the front of the main body. Therefore, it is preferable to set the braking force of the brake to be sufficiently small to prevent the construction machine from being overturned when the construction machine is stopped while being able to stop the running construction machine for driving stability of the construction machine.

However, in the conventional hydraulic brake device, since the size of the hydraulic pressure supplied to the brake actuator is fixed, the hydraulic oil supplied to the brake actuator is set to have a pressure intermediate between a pressure suitable for braking during driving and a pressure suitable for braking during operation. do. Therefore, there is a problem that the construction machine cannot stably maintain a stopped state during the operation operation, and there is a problem that there is still a possibility that the construction machine may fall during braking during the driving operation.

US 10-1997-0040698 A

An object of the present invention is to provide a hydraulic brake device capable of supplying hydraulic oil having pressures of different sizes depending on the type of operation of a construction machine to an actuator of a brake in order to solve the problems of the prior art.

In order to solve the above problems, the present invention, an actuator operated by hydraulic oil to generate a braking force; a work line for supplying hydraulic oil to the actuator; a traveling line having a flow path independent of the work line and supplying hydraulic oil to the actuator; a flow path switching valve operating between a first position for supplying hydraulic oil supplied from a hydraulic pump to the traveling line and a second position for supplying the working line to the working line; 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 flow path switching valve may be a solenoid valve.

In addition, the pressure reducing valve may be a relief valve that is opened when the pressure of the traveling line is greater than or equal to a preset pressure and drains a portion of the hydraulic oil of the traveling line.

In addition, it may further include a mode selection unit for switching the position of the flow path switching valve.

In addition, the work machine control unit sensor for detecting the operation of the work machine control unit; a driving control unit sensor for detecting an operation of the driving control unit; and receiving a signal from the work machine control unit sensor and the travel control unit sensor, and when it is determined that the work machine control unit is operated, the position of the flow path switching valve is switched so that hydraulic oil is supplied to the work line, and the traveling control unit is operated When it is determined, the control unit may further include a control unit for switching the position of the flow path switching valve so that the hydraulic oil is supplied to the travel line.

In addition, when on, the flow path selector valve 40 is switched to the second position 44 , and when off, the brake pressure selector 78 for switching the flow path selector valve 40 to the first position 42 . may further include.

According to an embodiment of the present invention, by supplying hydraulic oil to the brake actuator through any one of the work line and the travel line having a pressure lower than that of the work line, the braking force is increased during work and the braking force is reduced during driving to improve work stability and driving. There is an effect that the stability is improved at the same time.

In addition, according to an embodiment of the present invention, the position of the flow path switching valve is automatically switched when it is detected that the working device operating unit or the traveling operating unit is operated by the working device operating unit sensor and the traveling operating unit sensor, so that the user can use the working device operating unit and the traveling operating unit. It has the effect of being able to concentrate on the operation of the system and preventing accidents that may occur by operating the flow path switching valve incorrectly.

1 is a view showing the overall configuration of a hydraulic brake device according to an embodiment of the present invention.
2 is a view showing the relationship between the control unit and the flow path switching valve in the hydraulic brake device 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. First, in adding reference numerals to the components of each drawing, it should be noted that the same components are given the same reference numerals as much as possible even though they are indicated on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

1 is a view showing the overall configuration of a hydraulic brake device according to an embodiment of the present invention, Figure 2 is a view showing the relationship between the control unit and the flow path switching valve in the hydraulic brake device according to an embodiment of the present invention am.

Referring to FIG. 1 , the hydraulic brake device according to an embodiment of the present invention includes a front wheel actuator 22 , a work line 86 , a travel line 85 , a flow path switching valve 40 , and a pressure reducing valve 50 . do. Furthermore, the hydraulic brake device according to an 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 operated by hydraulic oil to brake the front wheel and the rear wheel, respectively. In the present embodiment, the front and rear wheel actuators 22 and 24 are illustrated as hydraulic cylinders, but the types of the front and rear wheel actuators 22 and 24 may be changed according to the type of brake. In this description, supplying hydraulic oil to the brake means supplying hydraulic oil to the actuator of the brake, and operating the brake means that the actuator of the brake is actuated by the hydraulic oil to cause the brake to generate 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 hydraulic oil to the front wheel actuator 22 and the rear wheel actuator 24, respectively. The pressure of the hydraulic oil 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 is Although shown to be supplied to the rear wheel actuator 24, only one hydraulic pump for supplying hydraulic oil to the front and rear wheel actuators 22 and 24 may be provided, and at this time, the hydraulic oil supplied from the hydraulic pump is the front wheel actuator 22 and the rear wheel actuator 24 may be distributed and supplied.

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 hydraulic 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 flow path 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 flow path switching valve 40 or may be connected through another medium, which is also the second hydraulic oil supply line 84 . am.

The brake valve 30 is provided on the hydraulic oil supply lines 82 and 84, and the position of the brake pedal 60 is switched by operating the brake pedal 60, and thus the hydraulic oil discharged from the hydraulic pumps 12 and 14 is transferred to the actuators 22 and 24. side, or drain the hydraulic oil from the actuators 22 and 24 to the tank side. In other words, the brake valve 60 controls the flow direction of the hydraulic oil flowing along the hydraulic oil supply lines (82, 84). The brake valve 30 has a first position 32 for draining hydraulic oil from the front and rear wheel actuators 22 and 24, a second position 34 for supplying hydraulic oil to the front and rear wheel actuators 22 and 24, and a third It operates between positions 36 . If the user does not step on the brake pedal 60, the hydraulic oil discharged from the hydraulic pumps 12 and 14 as the brake valve 30 maintains the first position 32 is not supplied to the front and rear wheel actuators 22 and 24. The hydraulic fluid in the front and rear wheel actuators 22 and 24 is drained to the tank. When the user steps on the brake pedal 60, the brake valve 30 is switched to the second position 34, and accordingly, the hydraulic oil discharged from the hydraulic pumps 12 and 14 passes through the brake valve 30 to the front and rear wheels. It is supplied to actuators 22 and 24 . At this time, the second position 34 of the brake valve 30 is provided with an orifice inside the valve to reduce the flow rate of the hydraulic oil passing through the brake valve 30 . When the user presses the brake pedal 60 more deeply, the brake valve 30 is switched to the third position 36 , so that the maximum flow rate of hydraulic oil passes through the brake valve 30 . When the user takes their foot off the brake pedal 60 , the brake valve 30 returns to the first position 32 , so that the hydraulic oil of the front and rear wheel actuators 22 and 24 is drained into the tank.

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

The flow path switching valve 40 selectively connects the first hydraulic oil supply line 82 with the traveling line 85 or the work line 86 . The flow path switching valve 40 has a first position 42 connecting the first hydraulic oil supply line 82 with the travel line 85 and a second position 42 connecting the first hydraulic oil supply line 82 with the work line 86 . It operates between positions 44 . 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 travel line 85 or the work line 86 by the flow path switching valve 40 , the hydraulic oil supplied through the first hydraulic oil supply line 82 is transferred to the travel line 85 . ) or the work line 86 . That is, the flow path switching valve 40 selectively supplies the hydraulic oil supplied from the first hydraulic pump 12 to the travel line 85 or the work line 86 . The user may 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 brake device may be provided with a mode selection unit 76 that can be operated by the user. The mode selection unit 76 may be configured to select any one of a driving mode and a work mode. When the user selects any one of the two modes, it is transmitted to the control unit ( 70 in FIG. 2 ), and 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 travel line 85 to reduce the pressure of the hydraulic oil supplied to the front wheel actuator 22 . The pressure reducing valve 50 may be a relief valve that opens when the pressure in the travel line 85 is greater than or equal to a preset pressure and reduces the pressure in the travel line 85 by draining a portion of the hydraulic oil in the travel line 85 . Since both the traveling line 85 and the work line 86 receive hydraulic oil from the first hydraulic oil supply line 82 , the pressure of the hydraulic oil supplied to the travel line 85 is the pressure of the hydraulic oil supplied to the work line 86 . Although the same as above, the traveling line 85 is provided with a pressure reducing valve 50 so that the traveling line 85 may have a lower pressure than the working line 86 . The braking force of the brake is proportional to the pressure of the hydraulic oil supplied to the actuator. Therefore, since the pressure of the hydraulic oil supplied through the travel line 85 is smaller than the pressure of the hydraulic oil supplied through the work line 86 , when the hydraulic oil is supplied to the front wheel actuator 22 through the travel line 85 , it is relatively A small braking force can be generated, and when hydraulic oil is supplied to the front wheel actuator 22 through the work line 86, a relatively large braking force can be generated. Therefore, when the running line 85 is set to have an appropriate pressure for driving braking and the working line 86 is set to have an appropriate pressure for working braking, the hydraulic oil flows through the driving line 85 when the construction machine is running. By being supplied to the front wheel actuator 22, it is possible to generate a braking force suitable for driving braking, and during work, hydraulic oil is supplied to the front wheel actuator 22 through the work line 86 to generate a braking force suitable for work braking. In other words, it is possible to provide an appropriate braking force according to the type of operation of the construction machine even without changing the discharge pressure of the first hydraulic pump 12 .

The rear wheel actuator 24 is operated by hydraulic oil supplied through the second hydraulic oil supply line 84 to generate a braking force on the rear wheel. 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 greater than the pressure of the travel line 85 and smaller than the pressure of the work line 86 . Since braking is mainly performed by the front wheel brake during driving or work of the construction machine, hydraulic oil is selectively supplied to the front wheel actuator 22 through the driving line 85 or the working line 86, and the second hydraulic oil supply line to the rear wheel brake. By supplying hydraulic oil directly through (84), the brake system can be configured simply while improving working stability and driving stability. However, as with the front wheel actuator 22, hydraulic oil is selectively supplied to the rear wheel actuator 24 through the traveling line 85 and the work line 86, and the pressure reducing valve 50 is provided on the traveling line 85. It is self-evident that even if the configuration of the brake system becomes somewhat complicated, driving stability and working stability can be improved.

On the other hand, like the operation of the excavator digging the ground with a bucket, loading the soil into the bucket, moving the soil, and then emptying the soil from the bucket, the conversion of the work operation and the driving operation occurs repeatedly in the construction machine. Therefore, when the user manually operates the mode selection unit 76 to switch the flow path switching valve 40 during the operation of the construction machine, it causes inconvenience due to the frequent operation of the mode selection unit 76, and the user makes a mistake. If the raw mode selection unit 76 is incorrectly selected, there is a risk that the construction machine moves during operation or the construction machine falls during braking. Accordingly, in order to automatically switch the position of the flow path switching valve 40 , the hydraulic brake device may include a working machine control unit sensor 72 and a traveling control unit sensor 74 .

The work machine control unit sensor 72 may detect the operation of the work machine control unit and output it to the control unit 70 , and the traveling control unit sensor 74 may detect the operation of the traveling control unit and output it to the control unit 70 . The work machine operation unit is operated by the user to operate the work machine of the construction machine, and the running operation unit is operated by the user to drive the construction machine. When the control unit 70 determines that the working device operating unit is operated by the signal received from the working device operating unit sensor 72 , the control unit 70 operates the flow path switching valve 40 so that hydraulic oil can be supplied to the working line 86 . By switching to the second position 44, a large braking force can be generated at the front wheels. When the control unit 70 determines that the traveling control unit is operated by the signal transmitted from the traveling control unit sensor 74 , the control unit 70 operates the flow path switching valve 40 so that hydraulic oil can be supplied to the traveling line 85 . Switching to the first position 42 allows a relatively small braking force to be generated at the front wheels.

On the other hand, the hydraulic brake device may be provided with a brake pressure selector 78 that can be operated by the user. The brake boost selection unit 78 may be configured so that the user can operate it on/off. The brake boost selection unit 78 is for the user to arbitrarily increase the braking force of the brake. The on/off state of the brake boosting selection unit 78 is transmitted to the control unit 70 , and accordingly, the control unit 70 may output a control signal to control the position of the flow path switching valve 40 . When the brake pressure selector 78 is turned on, the control unit 70 switches the flow path switching valve 40 to the second position 44 regardless of whether the construction machine is in the driving mode or the working mode, thereby generating a large braking force to the front wheels. can make it happen In addition, the operation signal of the brake boost selection unit 78 may be directly input to the flow path switching valve 40 without going through the control unit 70 . At this time, when the brake boost selection unit 78 is turned on, the flow path selector valve 40 is switched to the second position 44, and when the brake boost selector 78 is turned off, the flow path selector valve 40 moves to the first position ( 42) can be converted to The user can realize a large braking force at any time by turning on the brake boost selector 78 .

The above description is merely illustrative of the technical idea of the present invention, and various modifications, changes and substitutions will be possible without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains. . Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the equivalent range should be construed as being included in 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 unit 72: work machine operation unit sensor
74: driving control unit sensor 76: mode selection unit

Claims (6)

an actuator operated by hydraulic oil to generate a braking force;
a work line for supplying hydraulic oil to the actuator;
a running line having a flow path independent of the work line and supplying hydraulic oil to the actuator;
a flow path switching valve operating between a first position for supplying hydraulic oil supplied from a hydraulic pump to the traveling line and a second position for supplying the working line to 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. According to claim 1,
The flow path switching valve is a solenoid valve hydraulic brake device. According to claim 1,
The pressure reducing valve is a hydraulic brake device, which is a relief valve that is opened when the pressure of the travel line exceeds a preset pressure and drains a portion of the hydraulic oil of the travel line. According to claim 1,
The hydraulic brake device further comprising a mode selection unit for switching the position of the flow path switching valve. According to claim 1,
a work machine control unit sensor for detecting the operation of the work machine control unit;
a driving control unit sensor for detecting an operation of the driving control unit; and
When it is determined that the working machine control unit is operated by receiving a signal from the working machine control unit sensor and the traveling control unit sensor, the position of the flow path switching valve is switched so that hydraulic oil is supplied to the work line, and it is determined that the traveling control unit is operated The hydraulic brake device further comprising a control unit for switching the position of the flow path switching valve so that when the hydraulic oil is supplied to the traveling line. The method of claim 1
When on, the flow path selector valve 40 is switched to the second position 44, and when it is off, a brake booster selector 78 for switching the flow path selector valve 40 to the first position 42 is further added. Includes hydraulic brake system.

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