JPH0726443Y2 - Excavator revolving structure - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a revolving superstructure of an excavator such as a power shovel, and more particularly to a revolving superstructure device which is fixed by applying a brake when stopped.

[0002]

2. Description of the Related Art An excavator of this kind such as a power shovel has a brake provided on a revolving structure, and the brake is applied when the engine is stopped. The brake is not released unless the revolving structure is rotated, thereby preventing accidents due to accidental rotation of the revolving structure.

FIG. 7 shows a hydraulic circuit of a conventional revolving structure apparatus, in which a revolving structure 2 attached to a revolving motor 1 is in a braked state. When the operating lever 3 is operated, pilot pressure is generated to move the spool of the direction switching valve 4, and the pressure switch 5 operates to switch the solenoid valve 6. Therefore, the pilot pump 7
Hydraulic fluid is discharged from the pilot line 8 through the solenoid valve 6 to the brake release cylinder 9, the brake is released, and the revolving unit 2 becomes rotatable. When the operation lever 3 is returned to the neutral position, the solenoid valve 6 returns to the illustrated position by the action of the timer 10 after a lapse of a certain time, the pressure oil of the brake release cylinder 9 communicates with the tank 11, and the revolving structure again. Two
The brake is applied to.

FIG. 8 shows a structure in which the pressure switch and the solenoid valve are eliminated. When the engine rotates and the pilot pump 7 is driven, hydraulic oil is led to the brake release cylinder 9 through the pilot pipe line 12. The brake of the revolving structure 2 is always released.

[0005]

Among the conventional techniques, the former does not release the brake of the revolving structure 2 when only the front attachment (not shown) of the excavator is actuated, and the external force in the horizontal direction is applied to the front attachment. When it works, there is no escape, and an overload is applied to the front attachment, the revolving structure, etc., causing a problem in durability. Therefore, the brake torque is set low, and the revolving unit 2 is caused to flow (the brake is loosened and dragged) to protect the front attachment and the like. Therefore, when transporting the excavator, the rotation of the revolving structure must be fixed by a lock pin or the like.

On the other hand, in the latter, when the engine is rotated and each hydraulic pump is driven, hydraulic oil flows into the brake release cylinder 9 and the brake is always released, so that the front is the same as the former. The attachment is not overloaded. However, when the operation lever 3 is set to the neutral position with the body tilted on a slope or the like, the swing motor 1
The problem arises that the revolving unit 2 flows by the leak amount and cannot be held.

Therefore, the turning body is fixed without using a lock pin for turning prevention so that an overload is not applied even when only the front attachment is operated, and the turning body does not flow due to leakage on a slope or the like. Therefore, a technical problem to be solved arises, and the present invention aims to solve this problem.

[0008]

This invention has been proposed to achieve the above object, and in an excavator in which a rotating body is braked so that its rotation can be locked, the brake is released. When the engine is rotated and the hydraulic pump is driven, the hydraulic pressure control means first operates the brake release cylinder at an intermediate pressure to release the brake halfway, and the vehicle turns. When the body is operated, the hydraulic control means is formed so that the brake releasing cylinder is operated at a high pressure to release all the brakes. Is provided, and a means for detecting a turning operation signal is provided, and a hydraulic control means for releasing the brake by applying an electric signal proportional to both signals to the solenoid valve is provided. And a pressure reducing valve for reducing the discharge oil of the hydraulic pump, and a solenoid valve for deriving the discharge oil of the hydraulic pump when a swing operation signal is detected. The present invention provides a revolving superstructure device for an excavator, which is provided with a hydraulic control means for selecting the hydraulic oil and releasing the brake.

[0009]

When the hydraulic control means is constituted by the means for detecting the engine rotation signal and the means for detecting the turning operation signal, the hydraulic control means first applies an electric signal proportional to the rotation signal at the time of engine start to the electromagnetic signal. Act on the valve to operate the brake release cylinder at intermediate pressure to release the brake halfway. Here, when the revolving structure is operated, the hydraulic control means causes an electric signal proportional to the engine rotation signal and the revolving operation signal to act on the solenoid valve to operate the brake release cylinder at high pressure to release all the brakes. To do.

Further, when the hydraulic control means is composed of the pressure reducing valve and the electromagnetic valve which is operated by the turning operation signal, when the engine is started and the hydraulic pump is driven, the shuttle valve of the hydraulic control means is operated first. Select the secondary pressure reduced by the pressure reducing valve, operate the brake release cylinder at the intermediate pressure, and release the brake halfway. Here, when the swing structure is operated, the solenoid valve is actuated by the swing operation signal to derive the discharge oil of the hydraulic pump, and this discharge oil is selected by the shuttle valve of the hydraulic control means, and the brake release cylinder is opened. Operates at high pressure to release all brakes.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a hydraulic circuit of a swing structure of an excavator, in which hydraulic oil discharged from a main hydraulic pump 21 is switched and adjusted by a direction switching valve 22 and sent to a swing motor 23.
In the illustrated state, the revolving structure 24 attached to the revolving motor 23 is in a braked state, and the solenoid valve 2
When the spool of No. 5 moves from the position of 25a to the position of 25b, the pressure oil of the pilot pump 26 is led to the brake release cylinder 28 through the pipe 27, the brake is released, and the revolving structure 24 is made rotatable. Become. In addition, the relief valve 2 is provided between the direction switching valve 22 and the turning motor 23.
9 and a check valve 30 are provided.

When the revolving unit 24 is rotated, the operating lever 31 is operated to guide the discharge oil of the pilot pump 32 to the pilot conduit 33 or 34, and either the pilot port 35 or the pilot port 35 of the directional control valve 22. Apply pilot pressure to 36. At this time, the pilot pressure in the pilot conduit 33 or 34 is selected by the shuttle valve 37 and sent to the pressure switch 38, and the turning operation signal i _B indicating that the operation lever 31 has been operated is output. This turning operation signal i
_B is sent to the controller 40 via the timer 39. When the operation lever 31 is returned to the neutral position,
The turning operation signal i _B is no longer output after the elapse of a certain time set by the timer 39. Further, when the engine 41 is started, the engine rotation signal i _{A is} sent from, for example, an alternator or the like.
The engine rotation signal i _A is sent to the controller 40.

The controller 40 is provided with a means for detecting the engine rotation signal i _A and a means for detecting the turning operation signal i _B. For example, the output signal I is transferred to the solenoid valve 25 in the relationship shown in FIG. Send to the solenoid. The solenoid valve 25 moves the spool when there is an output signal I from the controller 40, and sends hydraulic oil having a brake release pressure proportional to the output signal I to the brake release cylinder 28. That is, in FIG. 1, the controller 40 and the solenoid valve 25 constitute a hydraulic pressure control means 42. FIG. 3 is a graph showing the relationship between the brake release pressure and the brake torque, and the brake torque decreases in proportion to the increase of the brake release pressure.

More specifically, when the engine 41 is not rotating, i _A = 0, and since there is no output signal I from the controller 40, the solenoid valve 25 does not operate and the revolving structure 2
The brake torque applied to No. 4 is 100%. here,
When the engine 41 is started, the engine rotation signal i _A is input to the controller 40, and i _A =
If i ₁ , the output signal I becomes I ₁ . Then, the solenoid valve 25 obtains the brake release pressure Pα corresponding to the output signal I ₁ from the controller 40, and as shown in FIG.
Brake torque becomes α%. Therefore, the brake of the revolving structure 24 is released halfway, and even if an external force in the horizontal direction acts when the front attachment is operated in this state, the revolving structure 24 does not flow and the front attachment or the like is not overloaded. .

Next, the operating lever 31 is operated to operate the revolving unit 2.
4, when the pressure switch 38 is actuated and the turning operation signal i _B is input to the controller 40, and i _A + i ₂ = i _Z or i _B = i ₂ is set as shown in FIG. The output signal I becomes I ₂ . Then, the solenoid valve 25 obtains the brake release pressure Pβ corresponding to the output signal I ₂ from the controller 40, and the brake torque becomes 0% as shown in FIG. Therefore, all the brakes of the revolving unit 24 are released, and the revolving unit 24 freely rotates. That is, the brake torque is 100% when the engine is stopped,
The revolving structure 24 is in a fixed state without using a lock pin for preventing revolving. Then, when the engine is turned on, the brake torque automatically decreases to α%, and when the turning operation is performed, the brake torque becomes 0% and the brake of the revolving structure is released, so the front attachment is overloaded. Never give.

The electric processing in the controller 40 does not increase the output signal I stepwise as shown in FIG. 2, but increases the output signal I proportionally as shown in FIG. Can also obtain the same effect. FIG. 5 shows another embodiment of the configuration of the hydraulic control means 42, and a part of the oil discharged from the pilot pump 32 is led out to the pressure reducing valve 44 and the electromagnetic valve 45 through the pilot conduit 43. Pressure reducing valve 4
4 reduces the discharge oil of the pilot pump 32 to a constant pressure Pγ and sends it to the shuttle valve 46. When the pressure switch 38 operates and outputs a turning operation signal, an electric signal is input to the solenoid of the solenoid valve 45 via the timer 39, the spool moves from the position 45a to the position 45b, and the discharge oil of the pilot pump 32 is discharged. It is sent to the shuttle valve 46. The shuttle valve 46 compares the hydraulic pressures of both the hydraulic oil sent from the pressure reducing valve 44 and the hydraulic oil sent from the solenoid valve 45, selects one of the hydraulic oils having a high hydraulic pressure, and connects it to the pipe line 47. When the operation lever 31 is returned to the neutral position, the solenoid valve 45 returns to the position shown in the figure after a certain time set by the timer 39 has elapsed.

In FIG. 5, the pressure reducing valve 44 and the solenoid valve 45 constitute the control means 42. When the engine rotates to drive the hydraulic pump 21 and the pilot pump 32, the pilot pipe The hydraulic oil also flows through the passage 43 and is led out to the pressure reducing valve 44. In the illustrated state, the spool of the solenoid valve 45 is located at the position 45a, so that the hydraulic oil in the conduit 43 is shut off, and the hydraulic oil whose pressure has been reduced to a constant pressure Pγ by the pressure reducing valve 44 is sent to the shuttle valve 46 and the shuttle valve 46. The spool 46 moves to the opposite side, and hydraulic fluid is sent to the brake release cylinder 28. As described with reference to FIG. 3, the brake torque decreases in proportion to the increase of the brake release pressure, and as shown in FIG. 6, the secondary pressure Pγ of the pressure reducing valve 44 becomes the brake release pressure and the brake torque becomes γ%. Become. Therefore, the brake of the revolving structure 24 is released halfway, and even if an external force in the horizontal direction acts when the front attachment is operated in this state, the revolving structure 24 does not flow and the front attachment or the like is not overloaded. .

Next, the operating lever 31 is operated to operate the revolving unit 2.
4 is rotated, an electric signal is input to the solenoid of the solenoid valve 45 by operating the pressure switch 38, the spool moves, and hydraulic oil having the same pressure as the discharge pressure Pξ of the pilot pump 32 is sent to the shuttle valve 46. . Shuttle valve 46 is pressure reducing valve 4
The hydraulic pressure Pγ on the fourth side is compared with the hydraulic pressure Pξ on the solenoid valve 45 side, and the hydraulic oil on the solenoid valve 45 side having a high hydraulic pressure is selected and led to the brake release cylinder 28. Then, as shown in FIG. 6, at the brake release pressure Pξ, the brake torque becomes 0%, all the brakes of the swing structure 24 are released, and the swing structure 2 is released.
4 can rotate freely. That is, the same effect as that of the hydraulic circuit of FIG. 1 described above can be obtained.

The present invention can be variously modified without departing from the spirit of the invention, and it goes without saying that the invention extends to the modified version.

[0020]

As described in detail in the above embodiment, the present invention applies a brake to the revolving structure to fix the revolving structure when the engine is stopped, and the revolving structure is inadvertently used without using a lock pin or the like. Rotation can be prevented. Then, when the engine rotates and the hydraulic pump is driven, the brake is automatically released halfway, so even if horizontal force acts when the front attachment is operated, the revolving structure flows and the front attachment is overloaded. No load is applied. Further, when the revolving structure is operated, all the brakes are released and the turning action is not hindered.

Thus, there are various practical ideas such as that the workability of the excavator is remarkably improved and the durability of the machine is improved.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of an embodiment of a swing structure of an excavator.

[FIG. 2] Engine rotation signal i _A and turning operation signal i _B
And a graph showing the relationship between the output signal I from the controller.

FIG. 3 is a graph showing the relationship between brake release pressure and brake torque.

FIG. 4 is an engine rotation signal i _A and a turning operation signal i _B
And a graph showing the relationship between the output signal I from the controller.

FIG. 5 is a hydraulic circuit diagram of another embodiment of the swing structure of the excavator.

FIG. 6 is a graph showing the relationship between brake release pressure and brake torque.

FIG. 7 is a hydraulic circuit diagram of a swing structure of a conventional excavator.

FIG. 8 is a hydraulic circuit diagram of a conventional swing structure device for an excavator.

[Explanation of symbols]

21 hydraulic pump 24 revolving unit 25,45 solenoid valve 26,32 pilot pump 28 brake release cylinder 42 hydraulic control means 44 pressure reducing valve 46 shuttle valve i _A engine rotation signal i _B revolving operation signal I output signal

Claims (3)

[Scope of utility model registration request] 1. An excavator in which a revolving structure is braked to lock its rotation, and hydraulic control means for releasing the brake is provided so that the engine rotates to drive a hydraulic pump. First, the hydraulic pressure control means operates the brake release cylinder at an intermediate pressure to release the brake halfway, and when the swing structure is operated, the hydraulic pressure control means operates the brake release cylinder at a high pressure. A revolving structure for an excavator, which is formed so as to operate to release all brakes. 2. Means for detecting an engine rotation signal,
2. A revolving unit for an excavator according to claim 1, further comprising: a means for detecting a turning operation signal, and a hydraulic control means for applying an electric signal proportional to both signals to the solenoid valve to release the brake. apparatus. 3. A pressure reducing valve for reducing the discharge oil of the hydraulic pump, and a solenoid valve for deriving the discharge oil of the hydraulic pump when a turning operation signal is detected are provided, and one of the hydraulic oil is selected by a shuttle valve. The swing structure for an excavator according to claim 1, further comprising hydraulic control means for releasing the brake.