JPH0754812A - Stroke measuring device for hydraulic actuator - Google Patents

Abstract

PURPOSE:To effectively measure an expansion/contraction stroke by using a dummy hydraulic jack. CONSTITUTION:A hydraulic actuator 20A having a rotating drive shaft 1 is provided with a dummy hydraulic jack 20B connected to the hydraulic actuator 20A via a closed circuit; a stroke sensor 8 for detecting an expansion/contraction stroke of the hydraulic jack 20B; and a monitor 9 for displaying a detection signal of the stroke sensor 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stroke measuring device of a hydraulic actuator as a spike device applied to a gripper of a sharp bending machine for constructing a tunnel in a soft rock ground.

[0002]

2. Description of the Related Art As a measuring device of this type, for example, there is a stroke sensor of a hydraulic jack as shown in FIGS.

According to this, the stroke sensor 8 is composed of a sensor section 18 and a magnet section 19, and the sensor 1
When 8a moves relative to magnet 19a, sensor 18a
It is based on the principle that the relative positional relationship is calculated by integrating the number of magnetic field lines that cross each other.

The magnet portion 19 includes a piston rod 16
It is bolted to the hollow portion of the through the mounting hole 19b. Further, the sensor portion 18 is coupled to the head portion 17a of the cylinder 17 by a screw portion 18b so as to be concentric with the magnet portion 19.

Therefore, when the piston 15 reciprocates,
The sensor unit 18 moves relative to the magnet unit 19, and the position signal is displayed on a monitor (not shown).

[0006]

However, the stroke sensor described above is suitable for detecting the expansion / contraction stroke of the actuator in which the piston rod simply expands / contracts, but is incorporated in the actuator in which the piston rod rotates. It is very difficult to detect the expansion / contraction stroke of the actuator because it cannot be mounted in terms of flexibility and mounting space.

The present invention has been proposed in order to solve such a problem, and provides a stroke measuring device for a hydraulic actuator which can effectively measure the expansion and contraction stroke by using a dummy hydraulic jack. With the goal.

[0008]

In order to solve the above-mentioned problems, a stroke measuring device of a hydraulic actuator according to the present invention has a piston portion housed in a cylinder, and a pressure oil is supplied to oil chambers on both sides of the piston. In a hydraulic actuator equipped with a drive shaft that slides in the cylinder by supply and discharge and receives the rotational force of the motor output shaft by spline engagement, a dummy hydraulic jack connected to this hydraulic actuator in a closed circuit, A stroke sensor for detecting an expansion / contraction stroke of the hydraulic jack, and a monitor for displaying a detection signal of the stroke sensor are provided.

[0009]

According to the above construction, the stroke of the drive shaft of the hydraulic actuator is not directly measured but is indirectly detected by measuring the stroke of the dummy hydraulic jack. In addition, since the measuring device is not directly attached to the hydraulic actuator, there is room in the installation space for the device, and
Maintenance of each part is easily performed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

First, FIG. 2 shows a hydraulic actuator including a turning / extending / contracting drive shaft. The drive shaft 1 of the hydraulic actuator 20A is configured such that a spline 1a provided in the hollow portion meshes with a spline 2b provided on the output shaft 2a of the rotary motor 2 to transmit rotation.

Further, the drive shaft 1 has a piston portion 1b, and by receiving the pressure oil in the extension side port 3a, it moves in the cylinder 3 in the extension direction along the spline, and the compression side port 3b receives the pressure oil. It is designed to move in a contraction direction when received.

Next, FIG. 1 shows the overall structure of a stroke measuring apparatus according to the present invention. As shown, in addition to the hydraulic actuator 20A described above, a dummy hydraulic jack 2 is provided.
0B is provided.

In the hydraulic jack 20B, two dummy pistons 5 and 6 connected by a dummy piston rod 7 reciprocate in the dummy cylinder 4.

The port 5a of the dummy piston 5 is connected to the extension side port 3a of the hydraulic actuator 20A, and the hollow port in the drive shaft 1 is connected to the bypass port 1c, which is hydraulically connected in a closed circuit.

When the electromagnetic directional control valve 11 is operated and the dummy piston 6 receives the discharge oil of the hydraulic pump 10 and the dummy piston 5 sends the pressure oil to the expansion side port 3a, the drive shaft of the hydraulic actuator 20A. 1 rotates and extends in response to the movement of the dummy piston 6, but at this time, the oil component on the compression side of the piston 1b flows from the compression side port 3b to the port 5b of the dummy piston 5, and the shortage is the check valve. The oil is supplied from the hydraulic oil tank 12 through 13.

On the other hand, when the directional control valve 11 is operated and the dummy piston 6 receives the discharge oil of the hydraulic pump 10 and the dummy piston 5 sends the pressure oil to the compression side port 3b, the drive shaft 1 of the hydraulic actuator 20A rotates. However, it contracts in response to the movement of the dummy piston 6, but at this time, excess oil returns to the hydraulic oil tank 12 via the relief valve 14b.

The oil component on the extension side of the piston 1b is sent to the port 5a of the dummy piston 5 from the bypass port 1c and the extension side port 3a. 14a in the figure
Is a relief valve. In this way, the movement of the drive shaft 1 of the hydraulic actuator 20A corresponds to the movement of the dummy piston 6.

Finally, the stroke sensor 8 shown in FIGS. 3 and 4 is attached to the dummy piston rod 7, and the position signal thereof is displayed on the monitor 9.

[0020]

As described above, according to the present invention, the expansion / contraction stroke of the rotary drive shaft of the hydraulic actuator can be indirectly measured by measuring the expansion / contraction stroke of the piston rod of the dummy hydraulic jack. The effect that it can be obtained. Further, the stroke sensor used for measurement has advantages that it is highly marketable and easily available, and that it is located away from the hydraulic actuator and has good maintainability.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention.

FIG. 2 is a detailed sectional view of a hydraulic actuator.

FIG. 3 is a sectional view of a conventional hydraulic jack with a stroke sensor.

FIG. 4 is a detailed sectional view of a stroke sensor.

[Explanation of symbols]

 1 Drive shaft 2 Rotation motor 3 Cylinder 4 Dummy cylinder 5,6 Dummy piston 7 Dummy piston rod 8 Stroke sensor 9 Monitor 20A Hydraulic actuator 20B Dummy hydraulic jack

Claims (1)

[Claims] 1. A drive which has a piston portion housed in a cylinder, slides in the cylinder by supplying and discharging pressure oil to both side oil chambers of the piston, and receives a rotational force of a motor output shaft by spline engagement. In a hydraulic actuator equipped with a shaft, a dummy hydraulic jack connected to the hydraulic actuator in a closed circuit, a stroke sensor for detecting an expansion / contraction stroke of the hydraulic jack, and a monitor for displaying a detection signal of the stroke sensor. A stroke measuring device for a hydraulic actuator, comprising: