JPH0470528A - Pin-type load cell - Google Patents

Abstract

PURPOSE:To easily monitor the load at all times or upon necessities by attaching a strain gauge outside of each connecting pin which interlocks and couples two members and at a position corresponding to the confronting surfaces of the members in parallel to the load direction. CONSTITUTION:Flat surfaces 12a parallel to each other formed at side faces of a pin part of a load cell 12, each corresponding to a part where the inner face of a cross head 10 and an outer face of a rod 11 confront. A strain gauge 13 such as a multiple wire strain gauge is attached to each flat surface 12a. A communicating hole 15 communicating with a central hole 14 is provided in the flat face 12a to which the strain gauge 13 is attached. A lead wire 13a of the strain gauge 13 is inserted into the central hole 14 through the communicating hole 15, an end of which is connected to a connector 16. By connecting a dynamic strain amplifier and a digital display device or the like to the connector 16, the load impressed to the rod 11 or cross head 10 is displayed via the strain gauge 13. Accordingly, the load can be measured at all times or upon necessities.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a load cell that detects, for example, the operating force of a servo motor, and particularly relates to a pin-type load cell in which a strain gauge is attached to a connecting pin. .

Figure 4 is a diagram showing a general guide vane operating device for water turbines, which controls the opening of the guide vane.One end of the guide ring rod 2 is pivotally attached to the guide ring 1. The other end of the guide ring rod 2 is connected to an operating rod 4 of an electric servo motor 3, and the base end of the electric servo motor 3 is pivotally connected to a fixed part via a pin 5.

When the electric servo motor 3 is actuated and its operating rod 4 is advanced or retreated, the guide ring 1 is rotated in the circumferential direction via the guide ring rod 2, and the guide vanes are opened and closed.

By the way, as means for detecting the operating force of the servo motor as described above, a load detection switch is provided inside or outside the servo motor.

However, in such a device, it is easy to detect whether the load has reached the load setting value, etc.
It is not possible to detect operating forces during normal operation.

Furthermore, abnormalities in the operating force of servo motors, etc. may suddenly increase at one time, or the friction force may gradually increase due to friction in the mechanism, and in order to know the lifespan of the machine, it is necessary to check the friction force in the latter case. Although the increase needs to be monitored,
Conventional devices such as those described above have problems such as the inability to perform the above-mentioned monitoring.

In view of these points, it is an object of the present invention to provide a pin-type load cell that allows the load generated in a servo motor or the like to be easily monitored.

[Structure of the invention]

(Means for Solving the Problems) The present invention comprises a connecting pin that interlocks and connects two members to each other, and a load direction is placed on the outer surface of the pin portion at a position corresponding to the surface where both the members are adjacent to each other. It is characterized in that at least one strain meter is attached in parallel with.

(Function) When a load is applied from one member to the other, the strain produced on the pin is measured by the strain gauge attached to the connecting pin that connects the two, and this causes the strain to be applied to the other member. The load is measured. Therefore, by displaying this measured value on a digital display or the like, the load can be easily monitored at all times or as needed.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 3 is a partial plan cross-sectional view of a connecting portion between two members, such as the connecting portion between the guide ring rod 2 and the operating rod 4, in which a crosshead 10 provided on one member is connected to the other member. The tip of the rod 11 is connected to the tip of the rod 11 by a pin-shaped load cell 12. For example, when the crosshead 10 moves in the left-right direction in the figure, the rod 11 is actuated in the left-right direction via the pin-type load cell 12.

Incidentally, planes 12a, 12a parallel to each other are formed on both side surfaces of the pin portion of the pin type load cell 12 at positions corresponding to the portions where the inner surface of the crosshead 10 and the outer surface of the rod 11 face each other. On the plane 12a,
A strain gauge 13, such as a multi-axis resistance wire strain cage, is attached to each of them (FIGS. 1 and 2).

The plane 12a to which the strain gauge 13 is attached is provided with a communication hole 15 that communicates with the center hole 14 drilled in the axial direction in the pin portion of the pin type load cell 12, and the lead wire 13a of the strain gauge 13 is provided with a communication hole 15. is inserted into the center hole 14 through the communication hole 15, and the tip of the lead wire 13a is connected to a connector 16 installed in the head 12b of the pin type load cell 12.

The pin-type load cell 12 is inserted through the crosshead 10 and the rod 11 so that the plane 12a to which the strain gauge 13 is attached is parallel to the direction of the load acting on the pin-type load cell 12 (the direction of the arrow in FIG. 3). By tightening the nut 17 on the tip, it is possible to prevent the nut from coming out.

Further, the head 12b of the pin-type load cell 12 is fixed to the crosshead 10 by a locking bolt 18, so that even when the crosshead 10 or the rod 11 swings, the crosshead 10 and the pin-type load cell 12 are fixed to each other.
This is done so that the relative positions of the two do not change.

By connecting a display device having a dynamic strain amplifier, a digital display, etc. to the connector 16, the load applied to the rod 11 or the crosshead 10 is displayed on the display device via the strain gauge 13. The above load can be measured constantly or as needed.

In addition, in the above embodiment, the pin applied to the connecting part between the crosshead and the rod was shown, but it can also be applied to the connecting pin used to simply connect links together, so that it corresponds to the opposing surfaces of both links where the load is applied. By using a pin type load cell with a strain gauge attached to the portion, the load can be measured in the same manner as described above.

〔Effect of the invention〕

Since the present invention is configured as described above, by using this pin-type load cell as a connecting pin that connects parts through which power is transmitted to each other, load can be measured without providing special parts, and the load can be measured at all times. Alternatively, the load can be measured and monitored very easily if necessary. Therefore, it is possible to detect changes in load, detect whether frictional force is increasing due to an increasing tendency of load, etc., and detect abnormalities in operating equipment before they have a serious impact on equipment. Can be detected.

14... center hole, 15...Communication hole,

Claims (1)

[Claims] A connecting pin that interlocks and connects two members to each other is configured, and at least one strain gauge is attached to the outer surface of the pin portion in parallel to the load direction at a position corresponding to the surface where the two members are adjacent to each other. Features a pin-type load cell.