Device for controlling hydraulic pressure of construction machine

• US 20040060205A1
• Filed: 02/10/2003
• Published: 04/01/2004
• Est. Priority Date: 08/24/2001
• Status: Active Grant

• Current Assignee: Shin Caterpillar Mitsubishi Ltd. (Caterpillar Incorporated)
• Original Assignee: Shin Caterpillar Mitsubishi Ltd. (Caterpillar Incorporated)
• Inventors: Yoshino, Kazunori
• Granted Patent: US 6,817,277 B2
• Time in Patent Office: Days
• US Class Current: 37/348
• CPC Class Codes: E02F 9/2025 Particular purposes of control systems not otherwise provided for E02F3/16, E02F3/26, sub-groups of E02F3/43, E02F3/651, sub-groups of E02F3/84, E02F3/907, E02F5/145 take precedence
• CPC Class Codes: E02F 9/2203 Arrangements for controlling the attitude of actuators, e.g. speed, floating function
• CPC Class Codes: F15B 21/082 with different modes
• CPC Class Codes: F15B 9/09 with electrical control means
• CPC Class Codes: G05D 16/2026 with a plurality of throttling means

Abstract

The invention relates to a hydraulic control apparatus for a construction machine. The hydraulic control apparatus includes a target velocity table (4) which stores target actuation velocities of a hydraulic actuator (30) corresponding to operation amounts of the operation member (2) to be operated by the operator, a target acceleration table (5) which stores target actuation accelerations of the hydraulic actuator (30) corresponding to operation amounts of the operation member (2), and one of the target velocity table (4) and the target acceleration table (5) can be selected by operation of a selection switch (3) by the operator. Further, by the control means, the target value corresponding to the operation amount of the operation member (2) using the table selected by the selection switch (3), and a control valve (17) for controlling the pressure oil supplying amount from a hydraulic pump (16) to the hydraulic actuator (30) is controlled based on the set target value. Consequently, the operation characteristic of the hydraulic actuator (30) can be changed in accordance with the liking of the operator.

Claims

1. A hydraulic control apparatus for a construction machine including a hydraulic pump (16), a hydraulic actuator (30) driven by pressure oil supplied from said hydraulic pump (16), a control valve for controlling a pressure oil supplying amount from said hydraulic pump (16) to said hydraulic actuator (30), characterized in that it comprises:

an operation member (2) for being operated by an operator;

a target velocity table (4) which stores target actuation velocities of said hydraulic actuator (30) corresponding to operation amounts of said operation member (2);

a target acceleration table (5) which stores target actuation accelerations of said hydraulic actuator (30) corresponding to operation amounts of said operation member (2);

a selection switch (3) for selecting one of said target velocity table (4) and said target acceleration table (5) in response to an operation by the operator; and

control means for setting a target value corresponding to an operation amount of said operation member (2) using one of said tables selected by said selection switch (3) and controlling said control valve (17) based on the set target value.

2. The hydraulic control apparatus for a construction machine as set forth in claim 1, characterized in that said control means includes:

first signal detection means (20) for detecting a first signal correlating to the actuation velocity or the actuation acceleration of said hydraulic actuator (30);

second signal calculation means (21) for differentiating or integrating the first signal to calculate a second signal correlating to the actuation velocity or the actuation acceleration of said hydraulic actuator (30) but different from the first signal;

comparison means (7) for selecting, in an interlocking relationship to the selection of said selection switch (3), one of the first signal detected by said first signal detection means (20) and the second signal calculated by said second signal calculation means (21) and comparing the selected signal with the target value; and

control signal production means (9) for producing a control signal for controlling said control valve (17) based on a comparison signal from said comparison means (7).

3. The hydraulic control apparatus for a construction machine as set forth in claim 2, characterized in that said control means further comprises:

a bandpass filter (10A) for passing a characteristic frequency of pressure vibration of said hydraulic actuator (30) and vibration component signals around the characteristic frequency but cutting a DC component;

a high-pass filter (10B) for extracting a positive vibration component signal from the vibration component signal passed through said bandpass filter (10A);

a low-pass filter (10C) for extracting a negative vibration component signal from the vibration component signal passed through said bandpass filter (10A); and

control signal correction means (11, 12) for correcting the control signal using the signal from said high-pass filter (10B) and the signal from said low-pass filter (10C).

4. The hydraulic control apparatus for a construction machine as set forth in any one of claims 1 to 3, characterized in that said hydraulic actuator (30) is a revolving motor for revolving an upper revolving unit of said construction machine with respect to a lower traveling unit.

5. The hydraulic control apparatus for a construction machine as set forth in any one of claims 1 to 3, characterized in that said hydraulic actuator (30) is a hydraulic cylinder of said construction machine.

6. The hydraulic control apparatus for a construction machine as set forth in any one of claims 1 to 3, characterized in that said hydraulic actuator (30) is a traveling motor for driving a lower traveling unit of said construction machine.

7. The hydraulic control apparatus for a construction machine as set forth in any one of claims 1 to 6, characterized in that said target velocity table (4) can be selected as a basic table and said target acceleration table (5) can be selected when necessary by said selection switch (3).