JP3503472B2 - Revolving body brake device for construction machinery - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technical field of a brake device for braking a swing of a swing body in a construction machine such as a hydraulic excavator having an upper swing body on a traveling vehicle.

[0002]

2. Description of the Related Art In a construction machine such as a hydraulic excavator machine, an upper swing body is provided on a traveling vehicle, and a boom for performing work such as excavation is provided above the upper swing body.
A front attachment equipped with an arm and a bucket is attached. This upper revolving structure has a revolving hydraulic motor,
The turning is controlled by a switching valve that controls the flow rate and flow direction of the pressure oil supplied to the turning motor, and a remote control valve that remotely operates the switching valve. On the other hand, when the upper revolving structure is not operated to revolve, an accident may occur if the upper revolving structure freely turns by some external force during work or running, and it is inconvenient. Therefore, the turning of the upper revolving structure is braked. A mechanical brake for it is installed.

On the other hand, when a large rotational moment acts on the upper swing body by an external force while the mechanical brake is operating, the brake and speed reducer connected to the swing motor may be damaged. In such a case, it is necessary to release the brake. Therefore, in addition to the case of turning the upper-part turning body, a control system for releasing the braking of the brake as necessary has been conventionally used. Figure 3
Is an example showing a conventional control circuit of a brake device. The conventional circuit will be described below.

In FIG. 3, switching control valves 3 to 6 are provided on the oil passage 2 of the hydraulic pump 1, and the downstream thereof is connected to the oil tank T. The switching control valve 6 is a switching valve that controls the left traveling motor 14. Similarly, switching control valves 9 to 12 are provided on the oil passage 8 of the hydraulic pump 7, and the downstream thereof is connected to the oil tank T. The switching control valve 9 is a switching valve that controls the swing motor 13, and the switching control valve 12 is a switching valve that controls the right traveling motor 19.

A brake device 15 is connected to the rotary shaft 13a of the turning motor 13. The brake device 15 includes a brake desk 16, a brake shoe 17, and a hydraulic cylinder 18 for releasing the brake. The hydraulic cylinder 18 is internally provided with a spring 18a so that the brake shoe 17 is constantly pressed to perform a braking operation. Also, to release the braking operation, port 1 is
8b is provided, and braking is released when pressure oil is supplied to the port 18b. The port 18b is connected to the auxiliary hydraulic pump 24 by an oil passage 20.

A check valve 21 and a throttle 22 are inserted in parallel in the oil passage 20. The auxiliary hydraulic pump 24 also connects the neutral oil passages of the switching control valves 3 to 5 and 9 to 11 with the oil passage 23 branched from the oil passage 20, and is connected to the oil tank T. Therefore, when all the neutral oil passages are in the communicating state, the brake 15 holds the brake, and when any of the neutral oil passages is cut off, the brake 15 releases the braking.

The above-mentioned conventional apparatus is constructed as described above and functions as follows. First, a case of performing a turning operation will be described. When a turning remote control valve (not shown) is operated, the switching control valve 9 is switched in the turning direction, and hydraulic oil flows out to the turning motor 13. At the same time, the oil passage 23 is also blocked so that the hydraulic pressure rises. Therefore, pressure oil from the auxiliary pump 24 flows into the port 18b through the oil passage 20 and the check valve 21, the brake shoe 17 is pushed downward against the spring 18a, and the brake is released. As a result, the turning motor 13 rotates.

Further, when the turning control valve is returned to the neutral state when the turning is stopped, the switching control valve is also returned to the neutral state, and the turning motor 13 is delayed and stopped due to inertia. On the other hand, since the oil passage 23 communicates with the oil tank T, the pressure drops,
The oil pressure of the oil passage 20 also decreases. Since the pressure oil in the hydraulic cylinder 18 flows through the port 18b and the throttle 22, the brake shoe 18 slowly moves upward, and the brake 15 operates after the turning motor stops.

Next, the case of operating another actuator will be described. Since the oil passage 23 communicates with the neutral control oil passages of the switching control valves 3 to 5 and 10 and 11 in addition to the switching control valve 9 for the swing motor, these switching control valves 3 to 5 and 10 and 11 are connected. The oil passage 23 is also blocked when operating the actuator connected to the secondary port. Therefore,
In these cases as well, the braking of the braking device is released. Actuators controlled by these switching control valves include boom cylinders, arm cylinders, bucket cylinders, etc., as disclosed in, for example, Japanese Patent Publication No. 4-44650. The brake device disclosed in the above publication has almost the same structure,
Works the same way.

[0010]

As described above, in the above conventional device, the braking of the brake device is not released when no operation is performed or when only operation is performed. However, even if only the traveling operation is performed, it is common for the bucket to move while the soil is piled up.In this case, if the steering wheel is suddenly turned off, a very large inertial force will act and the braking force will increase. It may lose power and start sliding. If such a situation is repeated, the degree of wear of the friction plate becomes large, the braking force is lost, and it may cause an accident, which is a problem.

In addition, when the arm or bucket is operated in the air without excavation work, the braking of the brake is released. Therefore, on a sloping ground, the boom position is changed from the work position due to an oil leak of a turning motor or the like. There was a problem that it could shift without knowing it, which was a problem. The present invention has been made under the background as described above, and it is an object of the present invention to solve the above problems and provide a brake device in which the brake is released when it is actually necessary to reduce the wear of the brake. I am trying.

[0012]

To solve the above problems, the present invention employs the following means. That is, claim 1
According to the invention described above, in a brake device capable of holding and releasing a swing of the swing body in a construction machine having an upper swing body, a first detection means for detecting traveling and a hydraulic pressure of a main oil passage of a hydraulic pump are detected. Second detecting means for detecting a turning operation, third detecting means for detecting a turning operation, a mechanical brake for braking the turning of the revolving structure, and control means for releasing the braking of the mechanical brake, the controlling means comprising: When the turning operation is detected, the brake is released, and the brake is held after a lapse of a fixed time after the end of the turning operation,
When the oil pressure in the main oil passage rises above a predetermined pressure or rises above a predetermined speed, the brake is released, and when the oil pressure falls below the predetermined pressure, the brake is held after a certain period of time has elapsed. In addition, when traveling is detected and the hydraulic pressure of the main oil passage rises above a certain pressure or rises above a certain speed, the brake is released for a short period of time, and the brake is held after the passage of time. It is characterized by doing.

The invention of claim 1 is characterized mainly in that first to third detecting means are provided, and a control means for holding and releasing the braking of the brake is provided in a predetermined case based on the detection results. To do.

According to a second aspect of the present invention, in the first aspect of the invention, the first and third detecting means are pressure switches, the second detecting means is a pressure sensor, and the mechanical brake is A hydraulic cylinder is provided with a spring and an oil inflow port, the spring constantly performs a braking and holding operation, and a braking release operation is performed when a hydraulic pressure is applied to the oil inflow port. Connected to the auxiliary hydraulic pump via a solenoid valve,
The solenoid of the solenoid valve is provided with a controller that outputs a solenoid current based on the signals of the first to third detection means. Further, the invention according to claim 3 is, in the invention according to claim 1 or claim 2, which is a case where traveling is detected and steering is turned during a steady traveling to change direction, or traveling is started, When the hydraulic pressure in the main oil passage rises above a predetermined pressure or rises above a predetermined speed, the brake release operation of the mechanical brake is performed only for a short time so that the working machine does not deviate from the track even on a slope. It is characterized in that control is performed so as to perform a braking holding operation of the mechanical brake after a short time has passed.

[0015]

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows a circuit configuration of an embodiment of the present invention. FIG. 2 shows a pressure change of the hydraulic pump in the traveling state of the present embodiment. Embodiments of the present invention will be described below with reference to the drawings. The same components as those described in the conventional device are designated by the same reference numerals, detailed description thereof will be omitted, and different components will be described in detail.

In FIG. 1, a remote control valve 33 is connected to both pilot ports of a switching control valve 9 for controlling the swing motor 13 via oil passages 30 and 31. Oil passage 30, 3
1 is connected to the input port of the shuttle valve 34 by a branched oil passage, and the output port of the shuttle valve 34 is connected to the pressure switch 35.
Are connected, and the output end of the pressure switch 35 is connected to the input end of the controller 36. Also, the hydraulic pump 1,
The input port of the shuttle valve 38 is connected to the oil passages 2 and 8 of 7 by a branched oil passage. The output port of the shuttle valve 38 is connected to the pressure sensor 39, and the pressure sensor 39
The output end of is connected to the input end of the controller 36.

The oil passage 41 of the auxiliary pump 40 communicates with the neutral oil passages of the traveling switching valve control valves 6 and 12 via the throttle 42.
It is connected to the oil tank T. A pressure switch 43 is connected downstream of the throttle 42, and an output end of the pressure switch 43 is connected to an input terminal of the controller 36. The output end of the controller 36 is connected to the solenoid 46a of the solenoid valve 46 by the wiring 45, the output port of the solenoid valve 46 is connected to the port 18b of the hydraulic cylinder 18,
The input port of the solenoid valve 46 is connected to the auxiliary pump 40 and the oil tank T.

The controller 36 outputs a solenoid current Y1 according to the following rules based on the on / off signal X3 from the pressure switch 35, the signal X2 from the pressure sensor 39, and the on / off signal X1 from the pressure switch 43. In the following rules, the symbols V1 and V2 are preset or predetermined values, and V1 and V2 may be the same value. t1, t2, and t3 are also preset or predetermined times.

When X1 is on and X2 <V1, the current Y1 is off, X1 is on, and X2 ≧ V
In the case of 1, the current Y1 is turned on for a short time t1. When X2 ≧ V2, the current Y1 is turned on and X2 <
Even when it reaches V2, it remains on for the time t2. When X3 is on, the current Y1 is turned on, and even when X3 is off, it continues to be on for the time t3.

The rule means that the brakes are not released during steady running except in special cases. That is, it means that the brake is released only for a short time t1 when the steering is turned to change the direction or the running is started during steady running. This prevents damage due to friction of the brake plate even if a large rotational torque is generated by the upper revolving superstructure when the upper revolving superstructure rotates 90 degrees with respect to the traveling direction and is suddenly started. The purpose is to prevent damage due to the friction of the brake plate in the same manner even when the direction is suddenly changed during steady running and a large rotating torque is generated by the upper swing body. It should be noted that the time t1 is defined as a short time in which the work machine does not run away even if the work machine is on a slope.

The rule is that the brake is not released when X2 <V2, the brake is released when X2 becomes ≧ V2, and the brake release is stopped after a lapse of time t2 when X2 <V2. Means that. That is, for example, when a large rotating torque is not generated as in the case of operating an excavator in the air, the braking of the brake is not released, and when the excavating work is started, a large rotating torque acts on the upper revolving structure. Release braking. Further, in consideration of the case where the excavation work is continuously performed repeatedly, the consideration time of the time t2 is provided.

The rule means that when the turning operation is performed, the braking brake is released, and the release is continued for a fixed time t3 even after the turning operation is stopped. When the turning operation is performed, it is natural that the braking brake is released, but the release of the check valve 21 and the throttle 22 shown in FIG. 3 is omitted in the circuit of the embodiment of FIG. This is because. That is, the braking brake continues to be released while the turning motor 13 is rotating due to inertia.

Since this embodiment is constructed as described above,
It works as follows. The case of traveling will be described with reference to FIG. At the start of running, the discharge pressures of both hydraulic pumps 1 and 7 suddenly increase. In this case, the signal X1 of the pressure switch 43 is turned on, and the signal X2 of the pressure sensor 39 is the hydraulic pressure at which the discharge pressures of the hydraulic pumps 1 and 7 are large as shown in the figure. Therefore, according to the rule, X2 is the predetermined hydraulic pressure V1.
From the moment it becomes larger, Y1 is turned on for a short time t1 and the braking is released.

When the steering is turned and the direction is changed during steady running, one of the discharge pressures of the hydraulic pumps 1 and 7 increases and the other decreases. Therefore, the signal X2 suddenly rises as shown in the figure and becomes larger than the hydraulic pressure V1. In this case as well, the brake is released for a short time t1 in the same manner as described above. In addition,
When the steady running is continued, the discharge pressure X2 is smaller than the predetermined hydraulic pressure V1 as shown in FIG. 2, so Y1 is turned off and the braking of the brake 15 is maintained.

At the time of work such as excavation work, a high discharge pressure is applied to both of the main oil passages of the hydraulic pumps 1 and 7 as when the work machine is moved at a low speed in the air such as changing the posture of the work machine. When the oil pressure does not occur, that is, when both oil pressures are lower than V2, the output Y1 is turned off according to the rule, and the oil pressure is V
When the value exceeds 2, the output Y1 is turned on and the brake braking is released. Further, even if the oil pressure drops below V2, the output Y1 is turned on for a certain time t2, and the brake braking is continuously released.

During the turning operation of the turning body, the signal X3 from the pressure switch 35 is turned on, and the output Y1 is turned on according to a rule. Further, when the turning operation is stopped, the output Y1 is kept on for a certain time t3. As a result, the braking brake holds the braking after the turning motor 13 is stopped.

In view of the configuration and functions described above, the present embodiment releases the braking for a short time at the time of starting the traveling or at the time of changing the direction during traveling, and at the time of working, when a large rotational torque such as during excavation acts. Only by releasing the braking, and by releasing the braking for the required time even during turning operation, damage due to abrasion of the friction plate of the brake is prevented, so that the life of the braking device is extended and the work machine on a sloping ground. Since the braking is maintained when the is operated in the air, there is no inconvenience that the working position is displaced due to an oil leak or the like, so that the work is facilitated.

Further, even if the braking is released during traveling, it takes only a short time, and there is no inconvenience that the working machine escapes even on a sloping ground. In the present embodiment, the discharge pressure of the hydraulic pump is set in order to set the brake release conditions at the time of traveling and at the time of operating the working machine, but the rising speed of the discharge pressure may be adopted instead.

The embodiments and examples of the present invention have been described in detail above with reference to the drawings. However, the specific structure is not limited to the examples, and the design is modified within the scope not departing from the gist of the present invention. Etc. are included in the present invention.

[0030]

As described above, according to the configuration of the present invention, the braking of the brake is released when a large rotational moment occurs during traveling, work, and turning operation, and the friction plate is damaged by abrasion. As a result, the effect of extending the life of the brake device is obtained. Further, when the working machine is operated in the air on a sloping ground, since the braking is maintained, there is no inconvenience that the working position is displaced due to an oil leak or the like, so that the work is facilitated.

[0031]

[Brief description of drawings]

FIG. 1 shows a circuit configuration of an embodiment of the present invention.

FIG. 2 is a diagram illustrating a state change at the time of running start and at the time of changing direction.

FIG. 3 is a diagram showing a circuit configuration of a conventional device.

[Explanation of symbols]

1, 7 hydraulic pump 13 Swing motor 14, 19 Traveling motor 15 Mechanical brake 16 brake desk 18 Hydraulic cylinder for brake release 35 Pressure switch (third detection means) 36 controller (control means) 39 Pressure sensor (second detection means) 43 Pressure switch (first detection means)

Claims (3)

(57) [Claims] In a construction machine having an upper swing body, a brake device capable of two operations, a brake holding operation for holding a swing of the swing body by a brake and a brake release operation for releasing a brake, is provided. Detecting means, second detecting means for detecting the hydraulic pressure of the main oil passage of the hydraulic pump, third detecting means for detecting the turning operation, mechanical brakes for braking the turning of the revolving structure, and braking holding of the mechanical brakes. Operation and a control means for controlling a brake release operation for releasing the brake holding operation, the control means performs a brake release operation of the mechanical brake when a turning operation is detected, and a fixed time after the turning operation is completed. When the hydraulic pressure in the main oil passage rises above a predetermined pressure or rises above a predetermined speed, the brake release operation of the mechanical brake is performed while the brake holding operation is performed after the passage of time. When the oil pressure falls below the predetermined pressure, the braking holding operation of the mechanical brake is performed after a certain period of time has elapsed, the running is detected, and the oil pressure in the main oil passage rises above a certain pressure. Of the construction machine, the brake release operation of the mechanical brake is performed only for a short time when the speed rises above a certain speed, and the brake holding operation of the mechanical brake is performed after the short time has passed. Revolving structure brake device. 2. The first and third detecting means are pressure switches, the second detecting means is a pressure sensor, and the mechanical brake is provided with a spring and an oil inflow port in a hydraulic cylinder. A braking holding operation is performed at all times, and a braking release operation is performed when hydraulic pressure is applied to the oil inflow port, and the control means is connected to an auxiliary hydraulic pump via an electromagnetic valve at the port,
The revolving structure brake apparatus for a construction machine according to claim 1, wherein the solenoid of the solenoid valve is provided with a controller that outputs a solenoid current based on the signals of the first to third detection means. 3. When the traveling is detected and the steering is turned during the steady traveling to change the direction or the traveling is started, when the hydraulic pressure in the main oil passage rises above a predetermined pressure or at a predetermined speed or more. When rising, perform a braking release operation of the mechanical brake for a short time so that the working machine does not run off the track even on a sloping ground, and control to perform a braking holding operation of the mechanical brake after the short time has elapsed. The revolving structure brake device for a construction machine according to claim 1, wherein: