JPH04366237A - Slewing controller for hydraulic shovel - Google Patents

Abstract

PURPOSE:To provide a slewing controller for a hydraulic shovel capable of obtaining optimum slewing workability at all times. CONSTITUTION:The attitude of an attachment and a change as a slewing inertial body 12 by the presence of an end attachment are detected by the pressure (holding pressure) of a boom cylinder 13. A detecting signal is taken in as the signal of a check valve 16 with a variable throttle, in which throttle opening is increased when the inertial body is large and throttle opening is reduced when the slewing inertial body is small, and a selector valve 5 is changed over by the pressure signal of the check valve 16 with the variable throttle.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swing control device for a hydraulic excavator.

0002

2. Description of the Related Art A conventional example is shown in FIG. A motor 2 is installed to drive the rotating inertia body 1, and its movement is controlled by a switching valve 5. The switching valve 5 uses the sub pump 8 as a hydraulic pressure source and is switched in response to hydraulic pressure controlled by a pressure reducing valve type lever 7. When the rotating inertial body 1 rotates and is stopped, when the lever 7 is returned to neutral in steps, the switching valve 5 is also switched accordingly, causing a sudden brake on the motor 2 and a shock to the main body. Occur. In order to alleviate this shock, a check valve 11 with a throttle is provided in the pilot line 9, and even if the lever 7 is returned to neutral in steps, the switching valve 5
is switched slowly, and the inertial body 1 is slowly stopped.

According to this method, the inertial load changes depending on the attitude of the attachment and the state of the load, and if the check valve 11 with throttle is set, it is not possible to satisfy all turning operability.

0004

Problems to be Solved by the Invention The inertia of a hydraulic excavator as a revolving body varies greatly depending on the attitude of its attachments (boom, arm, bucket, etc.). The inertial mass of the rotating body becomes large when the vehicle is in the maximum reach position, and the mass becomes small when the vehicle is in the minimum turning position. The mass also changes depending on whether there is a load in the bucket or the like. Therefore, even if a check valve 11 (Fig. 5) with a throttle is installed in the operating system (pilot line) to reduce the shock when the swing is stopped, the inertia load changes depending on the attitude of the attachment, etc. It was not possible to set the settings, and optimum operability could not be obtained. SUMMARY OF THE INVENTION In view of these circumstances, it is an object of the present invention to provide a turning control device that can always provide optimum turning operability.

[0005]

[Means for solving the problem] Changes in the swinging inertial body due to the attitude of the attachment and the presence or absence of a load on the end attachment are detected by boom cylinder pressure (holding pressure), and the detection signal is sent when the inertial body is large. When the throttle opening is large and the rotating inertia body is small, the throttle opening is taken as a signal of the variable throttle check valve 16 which becomes small, and the switching valve 5 is switched by the pressure signal of the variable throttle check valve 16.

Further, the boom cylinder pressure is processed by a controller 18 and converted into an electric signal, and the throttle opening is controlled by a check valve 19 with an electromagnetic proportional variable throttle.

Furthermore, as an inertial load detection method, an angle sensor is used as a controller, and an electric signal from the controller is used to control the aperture opening.

[0008]

EXAMPLE FIG. 1 shows an example of the present invention. Changes in the inertial body 12 due to the attitude of the attachment, etc. are detected as changes in the driving pressure (holding pressure) of the boom cylinder 13 as a signal by the shuttle valve 14 (if only the holding pressure is used, only the check valve 17 is used to hold only the holding pressure side). (A method that detects pressure may also be used.) This signal pressure line 15 is connected to the check valve 1 with variable throttle.
6 variable aperture. If the relationship between the signal pressure and the throttle opening is set as shown in Figure 4, that is, the throttle opening changes in proportion to the signal pressure P, the attachment posture can be adjusted to the maximum reach (with a load). In this case, the holding pressure will be higher. At this time, the throttle opening is set to be the maximum, and since the holding pressure is the minimum in the case of minimum rotation (no load), the throttle opening at this time is set to be the minimum.

[0009] As a result, inertial bodies 1 to 1 as rotating bodies
When 2 is large, the aperture opening can be made large, and when the rotating inertia body is small, the aperture opening can be made small. As a result, when the lever 7 is returned to neutral in steps to stop the swing inertia body 1, when the swing inertia is large, there is no shock due to inertia, and when the swing inertia is small, the throttle is Since the switching valve 5 is small, the switching valve 5 returns to the neutral position slowly, so that shock can be eliminated.

0010

[Operation] Changes in the attitude of the attachment are taken out to the signal pressure line 15 as changes in the holding pressure of the boom cylinder 13, and applied to the variable throttle of the check valve 16 with variable throttle, and the signal pressure and throttle opening are adjusted as shown in Figure 5. Set it like the relationship. As a result, when the holding pressure is large (swinging inertia: large), the throttle opening is large, and when the rotating body is stopped, the flow shock is small due to inertia even if the lever 7 is returned to neutral in a stepwise manner. On the other hand, when the holding pressure is small (when the turning inertia is small) and the throttle opening is small, the switching valve 5 returns slowly and the shock can be alleviated.

Next, FIG. 2 shows an example in which the same function is performed using a controller 18, and its electrical output is realized by an electromagnetic proportional variable throttle check valve 19 to achieve the relationship shown in FIG.

The system shown in FIG. 3 does not use the boom cylinder pressure (holding pressure) as a signal, but rather uses an angle sensor 21 and a controller 22 to measure the attitude of the attachment, and controls the opening of the variable diaphragm depending on the attitude. It is a method.

[0013]

[Effect] Changes in the attitude of the attachment and the presence or absence of a load on the end attachment as a rotating inertial body are detected by the boom cylinder pressure (holding pressure), and this detection signal is used to indicate when the swinging inertial body is large, the throttle opening is large, When the rotating inertia body is small, the opening degree of the throttle is taken as a signal from the variable throttle check valve 16, etc., and the switching valve 5 is switched by the signal from the variable throttle check valve 16, etc. With this configuration, it is possible to achieve optimal turning operability, that is, to reduce shock when stopping, regardless of the attitude of the attachment and the presence or absence of a load on the end attachment.

[Brief explanation of drawings]

FIG. 1 shows a first embodiment circuit of the present invention.

FIG. 2 also shows a second embodiment circuit.

FIG. 3 similarly shows a third embodiment circuit.

FIG. 4 is a diagram showing the relationship between the signal pressure throttle opening degree of a check valve with a variable throttle.

FIG. 5 is a known circuit diagram.

[Explanation of symbols]

1 Rotating inertial body 2 Motor 3 Relief valve 4 Check valve 5 Switching valve 6 Main pump 7 Pressure reducing valve type lever 8 Sub pump 9 Pilot line 10 Parking brake 11 Check valve with throttle 12 Inertial body 13 Boom cylinder 14 Shuttle valve 15 Signal pressure line 16 Check valve (with variable throttle) 17 Check valve 18 Controller 19 Check valve with variable throttle 20 Electric circuit 21 Angle sensor 22 Controller

Claims (3)

[Claims] Claim 1: Changes in the attitude of the attachment and the presence or absence of a load on the end attachment as a swinging inertia body are detected by boom cylinder pressure (holding pressure), and the detection signal is used to determine the throttle opening when the swinging inertia body is large. Check valve with variable throttle (16
), and the variable throttle check valve (1
A swing control device for a hydraulic excavator, characterized in that the switching valve (5) is switched by the pressure signal of 6). [Claim 2] The boom cylinder pressure is controlled by a controller (1
2. The swing control device for a hydraulic excavator according to claim 1, wherein the signal is processed in step 8) and converted into an electric signal, and the throttle opening is controlled by an electromagnetic proportional variable throttle check valve (19). 3. The swing control device for a hydraulic excavator according to claim 1, wherein an angle sensor is used as a controller to detect the inertial load, and an electric signal from the controller is used to control the aperture opening degree.