KR100274380B1 - A hydraulic system for controlling a damping device and a shock absorber device of wheel type excavator - Google Patents

Abstract

PURPOSE: Brake device of a wheel typed excavator and a hydraulic system for controlling a suspension are provided to prevent a parking brake device from being damaged, to simplify structure by simplifying a circuit and to improve operation reliability. CONSTITUTION: Hydraulic system comprises two hydraulic pumps(2a,2b) driven by an engine(1); a travelling brake cylinder(7) actuated by one of the hydraulic pumps; a parking brake cylinder(13) and a suspension locking cylinder(16) actuated by the other of the hydraulic pump; a travelling brake valve(5) mounted between the hydraulic pump and the travelling brake cylinder; a first channel converting solenoid valve(10) installed between the hydraulic pump and the parking brake cylinder; a second channel converting solenoid valve controlling the suspension locking cylinder; and a third channel converting solenoid valve(20) mounted between the travelling brake valve and a brake cutoff valve(3) to control actuation of spool in the travelling brake valve.

Description

Hydraulic System for Braking and Suspension Control of Wheeled Excavators

1 is a hydraulic circuit diagram showing a system of a brake and a suspension of a conventional wheel type excavator.

2 is a hydraulic circuit diagram showing a system of a braking device and a suspension device of another conventional wheel time excavator.

3a to 3d is a hydraulic circuit diagram showing a system of a brake and a suspension of a wheel type excavator according to an embodiment of the present invention.

<Explanation of symbols for main parts of drawing>

1: engine

1a, 2b: hydraulic pump

3: braking cutoff valve

4: accumulator

5: running brake valve

7: Driving brake cylinder

13: parking brake cylinder

16: suspension lock cylinder

17: integrated switch unit

10: 1st flow path switching solenoid valve

12: 2nd flow path switching solenoid valve

20: 3rd flow path switching solenoid valve

18: diode

33: Running brake pedal

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake system and a hydraulic system for controlling a suspension device of various types of heavy equipment for construction (hereinafter, commonly referred to as a wheel type excavator) that can be driven, including wheel time excavators. A hydraulic system in which the devices can be operated independently or in combination with each other.

In wheel-time excavators, the field device is a device that acts to balance the machine during the operation of the machine and the slope operation.

On the other hand, the braking system of wheel type excavators generally includes a driving braking device that generates a braking force for stopping the equipment that is in operation, a parking braking device that prevents the equipment from flowing down when the equipment is stopped, and an excavation force during the digging operation of the equipment. It includes a work braking system that applies brakes on four wheels to ensure stable operation of the equipment by completely fixing the equipment from the rolling or pulling phenomenon caused by the equipment.

1 shows a system of a brake system and a suspension system of a conventional wheel type excavator, in which a plurality of hydraulic pumps 2a and 2b driven by a single engine 1 and the hydraulic pumps 2a and 2b are shown. The traveling brake cylinder 7, the parking brake cylinder 13 and the suspension lock cylinder 16 which are operated by the respective valves are installed. A brake cutoff valve 3, an accumulator 4, a traveling brake valve 5, and a pilot check valve 6 are installed in the flow path 31 connecting the hydraulic pump 2a and the traveling brake cylinder 7. In the oil passage 32 connecting the hydraulic pump 2b, the parking brake cylinder 13, and the suspension lock cylinder 16, respectively, a relief valve 14 is provided, whereby a predetermined pressure is formed in the oil passage 32. Meanwhile, a pedal or lever 33 operated by a driver is installed in the traveling brake valve 5 for operating the above-described traveling braking device, and each flow path switching for operating the suspension and parking braking device described above is performed. Solenoid valves 12 and 10 were installed. Moreover, the relief valve 14 was provided in this flow path 32, and predetermined | prescribed pressure was formed in the flow path 32. As shown in FIG. On the other hand, the driving brake valve 5 for operating the above-described driving braking device 5 is provided with a pedal or lever 33 operated by the driver, and each of the flow path switching solenoids for operating the above-mentioned suspension and parking braking device. The valves 12V and 10 are provided with respective electric switches 9 and 11 for receiving driving power from the respective batteries 8a and 8b when the driver operates.

In the braking system and suspension of the conventional wheel type excavator configured as described above, in the general driving state, the two electric switches 9 and 11 are turned on so that the two flow path switching solenoid valves 12 and 10 are switched. Accordingly, the hydraulic oil discharged from the hydraulic pump 2b is formed by the relief valve 14, and the suspension adjusting valve 15 is switched again through the solenoid valve 12, thereby suspending lock cylinder 16. The hydraulic fluid in the) was opened to have a suspension function, and the parking brake was released by acting on the parking brake cylinder 13 through the solenoid valve 10. In addition, the pilot check valve 6 loses the direction adjusting function of the pilot check valve 6 in the above-described flow path 31 through the pilot line 34, thereby traveling by the travel braking valve 5. The braking cylinder 7 can be operated, that is, the traveling braking device can be operated.

In order to switch from the driving state to the working state, first, the two electric switches 9 and 11 are turned off to cut off the driving power from the batteries 8a and 8b. When the electric switch 11 is turned off, Since the solenoid valve 10 is switched to the state shown in FIG. 1 to block the flow path 32, the hydraulic oil discharged from the hydraulic pump 2b is installed in the flow path 32 and the flow path 32. Return to tank (T) via relief valve (14). In addition, as the pressure applied to the pilot line 34 is removed, the pilot check valve 6 has a direction adjustment function. When the driving brake valve 5 is operated once in this state, the pilot check valve 6 is discharged from the hydraulic pump 2a. The stored hydraulic fluid is stored in the accumulator (4) through the brake cutoff valve (3), and then flows into the braking device through the driving brake valve (5), and continues between the pilot check valve (6) and the traveling brake cylinder (7). Pressure builds up, causing the parking brake and the driving brake to continue to operate.

On the other hand, when the electric switch 9 is turned OFF, the suspension regulating valve 15 is switched as shown in Fig. 1, and thus the suspension is locked.

However, in the braking system and the suspension of the conventional wheel type excavator as described above, in order to switch the driving state and the working state, as described above, the electric switches and the pedal or the lever had to be operated separately separately. It was accompanied by considerable inconvenience, and there was a high possibility of misoperation. In other words, the driver had to check and remember the operation state of each device part one by one, and the work efficiency was greatly reduced, and the brake system was fatally damaged during the misoperation. For example, a misoperation accident that occurs relatively frequently has a problem such that the parking brake device is damaged as the equipment is driven while the electric switch 11 is turned on.

On the other hand, the present applicant has filed a patent application No. 93-31448, "Hydraulic control system of wheel excavators" on December 30, 1993 to solve the above conventional problems.

In the above-described prior application technology, as shown in FIG. 2, an integrated switch unit 17 for electrically controlling the respective devices (braking device and suspension device) is provided, and the movable switch 17 has an operation. Depending on the switching position of the terminal SW (i.e. suspension lock position, travel braking position, parking braking position and work braking position), the suspension locking function, the driving braking function, the parking braking function and the working braking function are mutually separate or complex. Could be done with. On the other hand, in the flow path between the pilot check valve 6 and the traveling braking cylinder 7, a pressure switch 19 is turned on and off depending on the magnitude of the pressure acting on the flow path, and one side of the pressure switch 19 is provided. The terminal is connected to the work braking terminal W of the integrated switch 17 described above. In addition, a flow path 23 is installed between the accumulator 4 and the traveling braking cylinder 7, and the flow path switching solenoid valve 20, the pressure reducing valve 21, and the check valve 22 are installed in the flow path 23. It was installed sequentially. The terminal of the solenoid valve 20 is connected to the other terminal of the pressure switch 19 described above, so that the work braking terminal W of the integrated switch 17 is connected and the battery is turned on when the pressure switch 19 is turned on. The operating power was applied from (8) to open the flow path 23. Then, when a predetermined time has elapsed and the pressure in the flow path between the pilot check valve 6 and the traveling braking cylinder 7 described above increases, the pressure switch 19 is turned off, and the solenoid valve 20 flows through the flow path. Since the switching to the blocked state, the driving brake cylinder 7 is finally locked to the braking state to obtain a work braking effect.

However, in the above-described prior application technology, the damage of the parking brake function loss due to internal leakage of the pilot check valve 6 or pressure interference caused by the pressure of the driving braking system is applied to the parking brake cylinder 13 and the parking brake is broken. There was a fear of causing this. In addition to the aforementioned integrated switch unit 17, the flow path switching solenoid valve 20, the pressure reducing valve 21, the check valve 22, the pilot check valve 6, the pressure switch 19, and many other piping components This complicates the overall structure of the equipment and increases the probability of malfunction for each device.

Accordingly, an object of the present invention is to prevent damage to the parking brake system as described above, to simplify the structure of the equipment by simplifying the circuit, braking device and suspension device of the wheel type excavator that can improve the operation reliability of the equipment It is to provide a hydraulic system for control.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hydraulic system for controlling a brake and a suspension of a wheel type excavator, comprising: a plurality of hydraulic pumps driven by an engine; A driving brake cylinder operated by any one of the hydraulic pumps, a parking brake cylinder and a suspension lock cylinder operated by the other; A traveling braking valve installed between the one hydraulic pump and the traveling braking cylinder and moving a spring by a pedal or a predetermined pilot pressure to control the operation of the traveling braking cylinder; A first flow path switching solenoid valve installed between the other hydraulic pump and the parking brake cylinder to control an operation of the parking brake cylinder by receiving a predetermined electric signal; A second flow path switching solenoid valve installed between the other hydraulic pump and the suspension lock cylinder to control an operation of the parking brake cylinder by receiving a predetermined electric signal; A third flow path switching solenoid valve provided between the brake cutoff valve and the traveling brake valve to provide the pilot pressure for moving the spring of the traveling brake valve by receiving a predetermined electrical signal; And electric switching means for selectively applying the electrical signal from a predetermined electric supply source to operate the first, second and third solenoid valves independently or in combination, respectively. By providing a hydraulic system for device control.

According to a preferred feature of the present invention, the aforementioned switching means includes a suspension terminal connected to the first solenoid valve, and a conductive wire connected to the second solenoid valve and connecting the first solenoid valve from the suspension terminal. A driving braking terminal connected to the first solenoid valve, a work braking terminal connected to the third solenoid valve, a parking braking terminal not connected to any one of the first, second and third solenoid valves, The suspension terminal is connected between the movable terminal for connecting or disconnecting the terminals to the power supply and the conduit between the suspension terminal and the lead connecting the first solenoid valve to the running braking terminal. Reverse flow prevention die to prevent current from flowing from the air to the second solenoid valve Further included is a wood.

Hereinafter, preferred embodiments of the present invention will be described based on the accompanying drawings.

Prior to describing an embodiment of the present invention, it is to be noted that the same reference numerals will be given to the same components as those of the conventional hydraulic system described by FIGS. 1 and 2. In addition, the same general structure as the conventional hydraulic system is not redundantly described in this embodiment.

The hydraulic system of this embodiment is as shown in FIG. 3A.

According to FIG. 3a, two hydraulic pumps 2a, 2b driven by the engine 1 are provided, and the traveling braking cylinder 7 is operated to be operated by either one of the hydraulic pumps 2a, 2b. ) Is installed, the parking brake cylinder 13 and the suspension lock cylinder 16 is installed to be operated by the other (2b). Between the hydraulic pump 2a and the traveling braking cylinder 7 described above, a traveling braking valve 5 for controlling the operation of the traveling braking cylinder 7 is provided, and between the hydraulic pump 2b and the parking braking cylinder 13. The first flow path switching solenoid valve 10 for controlling the operation of the parking brake cylinder 13 is installed, and the suspension lock cylinder 16 is operated between the hydraulic pump 2b and the suspension lock cylinder 16. A second flow path switching solenoid valve 12 for controlling is provided. Further, a third flow path switching solenoid valve 20 for controlling the spring operation of the travel braking valve 5 is provided between the braking cutoff valve 3 and the travel braking valve 5.

On the other hand, in the hydraulic system of the present embodiment, an integrated switch unit 17 for electrically controlling the respective devices (braking device and suspension device) is provided. The integrated switch unit 17 operates the parking braking terminal P which cuts off the power supply of the first solenoid valve 10 and the second solenoid valve 12, the parking braking cylinder 13, and the second solenoid valve ( Suspension terminal (S) to cut off the power supply of 12, and supply power of the first solenoid valve 10 and the second solenoid valve 12, respectively, and the second solenoid valve ( 12) a driving terminal T connected to the first solenoid valve 10 through a backflow prevention diode 18 to prevent current from flowing through the third solenoid valve 20, and a first solenoid valve ( 10) and a work braking terminal (W) for shutting off the power supply of the second solenoid valve (12), for connecting or disconnecting the terminals (P, S, T, W) with the battery (8). The movable terminal SW is provided.

According to this embodiment, the suspension device can be locked according to the switching position (ie, suspension lock position, travel braking position, parking braking position and work braking position) of the movable terminal SW of one integrated yarn position 17, The driving braking function, the parking braking function and the working braking function may be performed separately or in combination with each other.

When the movable terminal SW of the integrated switch 17 is placed in the suspension lock position, only the suspension is locked and the other brakes are released. In addition, when the movable terminal SW is placed in the traveling braking position, all the devices are released. In addition, when the movable terminal SW is placed in the parking braking position, the parking brake is operated and the suspension is locked. In addition, when the movable terminal SW is placed in the work braking position, the driving braking device and the parking braking device are operated, and the suspension device is locked.

Hereinafter, the above operation will be described in more detail with reference to FIGS. 3A to 3D.

3A shows a parking braking state in which the solenoid valves 12, 10, and 20 are all electrically turned off, and the hydraulic oil discharged from the hydraulic pump 2b is returned to the tank T. As shown in FIG. Accordingly, when the hydraulic fluid in the parking brake cylinder 13 is returned to the tank, the parking brake device is in a braking state, and the suspension lock cylinder 16 is formed by the suspension control valve 15 to form a closed circuit. It is locked.

FIG. 3b shows the suspension locking state, in which the power supply from the battery 8 to the second solenoid valve 12 is cut off by the backflow prevention diode 18, while the first from the battery 8. Operating power is applied to the solenoid valve 10 so that the first solenoid valve 10 is switched to open the flow path. As a result, since the hydraulic oil supply from the second solenoid valve 12 to the suspension lock cylinder 16 is not made, the suspension lock cylinder 16 is locked by the closed circuit, while the parking brake cylinder 13 Since the hydraulic oil is supplied, the parking brake is released, and the driving brake is also released. As a result, the driving braking device operates in response to the operation of the driving braking pedal 33. In this way, it can be seen that in the suspension locking state, that is, in the state in which the movable terminal SW is connected to the suspension terminal S, the driving brake and the parking brake are released and only the suspension is locked.

3c shows the driving braking state, in which power is supplied from the battery 8 to the first and second solenoid valves 10 and 12 so that the two solenoid valves 10 and 12 open the flow path. Is switched to. Therefore, the hydraulic oil discharged from the hydraulic pump 2b is supplied to the suspension regulating valve 15 through the second solenoid valve 12 to switch the suspension regulating valve 15 to the open path, and the suspension apparatus The lock cylinder 16 is released by the open circuit. In addition, the hydraulic oil discharged from the hydraulic pump 2b is provided to the parking brake cylinder 13 through the first solenoid valve 10 to release the parking brake device, and the traveling brake device is also released. Thus, in this state, all devices are in a released state or in an independently operable state.

3d shows the working braking state. In this state, the power from the battery 8 is applied to the third solenoid valve 20 and the third solenoid valve 20 is switched to the illustrated state (the euro open state). Accordingly, the hydraulic oil stored in the accumulator 4 passes through the third solenoid valve 20 and acts on the spring of the traveling brake valve 5, thereby operating the traveling braking valve 5. The driving brake cylinder 7 is locked by being switched in the same manner as the pedal 33 is stepped on, and the traveling braking device is kept at a constant braking state at a predetermined pressure.

In this state, since power is not supplied from the battery 8 to the first and second solenoid valves 10 and 12, the hydraulic oil discharged from the hydraulic pump 2b passes through the relief valve 14. All of them are returned to the tank T. As a result, the driving brake and the parking brake are always kept in a locked state. A closed circuit is formed between the suspension control valve 15 and the suspension lock cylinder 16. It is locked. Therefore, the driving braking device, the parking braking device and the suspension device are all locked.

As described above, according to the present invention, the suspension locking function, the traveling braking function, the parking braking function, and the work braking function can be performed independently or in combination according to the switching position of the movable terminal of one integrated switch. In addition, the driver's operation convenience can be greatly improved, and the risk of misoperation can be reduced.

In addition, many components such as pilot check valves, pressure reducing valves, check valves, and pressure switches, which have been required in the prior art, are not required. Therefore, the structure of the equipment can be simplified, thereby reducing the cost and greatly improving the operation reliability of the equipment. Can be.

Claims (2)

A hydraulic system for brake and suspension control of a wheeled excavator, comprising: a plurality of hydraulic pumps driven by an engine; A driving brake cylinder operated by any one of the hydraulic pumps, a parking brake cylinder and a suspension lock cylinder operated by the other; A traveling braking valve installed between the one hydraulic pump and the traveling braking cylinder and moving a spring by a pedal or a predetermined pilot pressure to control the operation of the traveling braking cylinder; A first flow path switching solenoid valve installed between the other hydraulic pump and the parking brake cylinder to control an operation of the parking brake cylinder by receiving a predetermined electric signal; A second flow path switching solenoid valve installed between the other hydraulic pump and the suspension lock cylinder to control an operation of the parking brake cylinder by receiving a predetermined electric signal; A third flow path switching solenoid valve disposed between the brake cutoff valve and the traveling brake valve to provide a pilot pressure for moving the spring of the traveling brake valve by receiving a predetermined electrical signal; And electric switching means for selectively applying the electrical signal from a predetermined electric supply source to operate the first, second and third solenoid valves independently or in combination, respectively. Hydraulic system for device control According to claim 1, The switching means, Suspension terminal connected to the first solenoid valve; A traveling braking terminal connected to the second solenoid valve and simultaneously joined with a conductive line connecting the first solenoid valve from the suspension terminal to the first solenoid valve; A work braking terminal connected to the third solenoid valve; A parking brake terminal which is not connected to any of the first, second and third solenoid valves; A movable terminal for connecting or disconnecting the terminals to the power supply; And a confluence point between the running braking terminal and the conduit connecting the suspension terminal and the first solenoid valve to prevent current from flowing from the suspension terminal to the second solenoid valve when the suspension terminal is connected. Hydraulic system for braking and suspension control of a wheel type excavator, characterized by comprising a backflow preventing diode.