JPS6314998Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a machine tool chuck gripping force measuring device, and in particular to a machine tool chuck that can be attached to the chuck and measure the gripping force of the chuck when the machine tool is operating. This invention relates to a grasping force measuring device.

In recent years, as the rotational speed of the spindle of a turning machine has increased, safety in grasping a workpiece has become a problem.
As a countermeasure to this problem, methods have been developed for chucks, such as increasing the static gripping force and suppressing the loss of gripping force due to the centrifugal force acting on the jaw of the chuck during high-speed rotation, but there are problems with reliability. Therefore, we actually measure the gripping force of the chuck during high-speed rotation and set cutting conditions that match this gripping force.

The currently used measurement of grasping force during rotation is
As shown in Figure 1, chuck b of lathe a is equipped with a detecting part c having a sensor such as a strain gauge, and the output of detecting part c generated when chuck b is rotated is transmitted to a rotating part such as a slip ring or rotary transformer. There is one that takes out the signal through a relay section d, amplifies it, and then inputs it to a display device e for analog or digital display.

However, when the chuck grips the detection part c, since it is held in a cantilever manner, the rotational axis of the chuck and the rotational axis of the detection part c tend to be misaligned, and vibration occurs during rotation, resulting in unstable output from the rotary relay part. This has the drawback of decreasing measurement accuracy. Furthermore, if the sensor rotates at high speed with the rotational axis out of alignment, the detection section swings widely, which not only reduces measurement accuracy but also makes the measurement operation itself dangerous.
Furthermore, the chuck that grips the detection part has two or more jaws, and when the chuck rotates at high speed, the tip opens due to centrifugal force and the gripping force decreases, and the gripping force is reduced. Since the part is displaced in the axial direction together with the jaw, the misalignment between the axis of rotation and the axis of the detection part increases, which, together with a decrease in gripping force, results in extremely dangerous measurement work.

This invention eliminates the drawbacks of the conventional ones as described above, and supports the detection part and the rotary relay part that takes out the signal of the detection part by a chuck and a tailstock shaft of a tailstock provided on the lathe. To provide a gripping force measuring device for a chuck for a machine tool, which is capable of measuring the gripping force of a chuck even during high-speed rotation by preventing the axis of rotation of the chuck from being misaligned with the axis of rotation of a detection part. The purpose is to do.
In addition to the tailstock, the tailstock shaft that supports the rotating relay section is
It may be provided on a tool rest, a feed stand, or the like.

Embodiments of this invention shown in the drawings will be described below.

In Figs. 2 to 4, C is a detection unit formed into a polygon as shown in Fig. 3, and the detection button and support button 3
is provided. The support button 3 is provided only to align the center of rotation, and is screwed directly to the outer periphery of the main body.
A three-jaw chuck may be provided with any number of chucks as required, such as two. The detection button 1 is screwed to a strain shaft 2 that is fitted into a cylindrical hole C provided in the detector body C in the radial direction. The radial length and shape of each button 1 and 3 are determined by the dimensions of the chuck, the shape of the grasping part of the chuck, etc., and can be arbitrarily changed to suit the respective use.

The strain shaft 2 has a cylindrical hole on its lower end surface.
It is supported by coming into contact with the bottom surface of C', and a screw 6 is used to prevent it from coming out and preventing it from rotating. Further, a notch is provided in a part of the inner wall of the cylindrical hole C' to form a gap 5, and a strain gauge 4 is bonded to the strain shaft facing the gap 5.

When the strain shaft 2 configured as described above is grasped by the chuck, it produces a compressive strain proportional to the grasping force of the chuck, and this strain is converted into an electrical signal by the strain gauge 4, and an output corresponding to the strain is generated. It will be done. This output passes through a hole C' provided in the center of the main body C in the axial direction, is drawn out to the end face of the coupling part 8, is connected to the connector 10, and is connected to the connector 10.
The output relayed in is led through a hole A' provided in the rotating shaft 11 of the rotary relay A to a slip ring 13 by a lead wire 12. The slip ring 13 is kept insulated from the rotating shaft 11 and the adjacent slip ring 13 by a spacer ring 14 made of an insulating material. It is clamped and fixed between a stepped portion 16 of the rotating shaft 11 and a nut 17 that is screwed into a threaded portion at the end of the rotating shaft 11. The strain gauge 4 is guided to the slip ring 13 which rotates together with the rotating shaft 11.
In order to extract the output to the outside, a brush 18 is provided which makes sliding contact with the outer peripheral surface of the slip ring 13. This brush 18 uses its own elasticity to clamp the slip ring 13 with a constant force, so that stable conduction can be obtained even during rotation. The plate 19 is made of an insulating material and has a brush 18 attached thereto that holds the slip ring 13 therebetween, and also serves as an output relay terminal, and displays the output electrically connected to the brush 18 via a lead wire 20. Connector 2 connected to device e
Conducted to 1. Casing D of rotating relay A
A hole 30 is provided at the end opposite to the detection portion C, and a hole 31 that substantially communicates with the hole 30 is provided at the end of the rotating shaft 11. Inside the holes 30 and 31, a support bearing 22 having a large diameter end is fitted with the large diameter end in contact with the casing d, and the large diameter end and the casing d is fixed with a screw. Further, the center support bearing 22 is provided with a center hole 32 having a guide hole 23 that opens at the large diameter end and has a large diameter on the opening side, and further has a small hole 25 at the bottom of the center hole. It is perforated. A core support shaft 24 is disposed within the center hole 32 of the core support bearing 22 so as to be movable in the axial direction within the range of the large diameter opening of the guide hole 23, and a stem portion of the core support shaft 24 is provided. 26 is fixed with a nut 28 after passing through the compression coil spring 27 located inside the guide hole 23 and the small hole 25, so that there is a gap between the inner shoulder of the center support shaft 24 and the bottom surface of the center hole 32. The compression coil spring 27 is arranged in a preloaded state, and
This amount of preload can be adjusted by rotating the nut 28. A center hole 29 is provided at the center of the outer end surface of the support shaft 24 for supporting the center g of the tail stock f of the lathe.

When the gripping force measuring device configured as described above is to be gripped by a chuck, first advance the tail stock f of the lathe shown in Fig. 1 to the appropriate position, and push the center hole 29 of this measuring device into the center g of the tail stock f. After hitting it, operate the chuck b to grasp the main body C of the detection part. In this grasping operation, the support shaft 2
4 is guided by the center hole 29 and the center g of the tail stock f of the lathe to ensure the straightness of the center of the rotation axis of the lathe and chuck b and the center of the rotation axis of the measuring instrument, and the chuck yaw floats up when gripping. The grip force measuring device is pushed toward the tail stock f side, but the support shaft 24 compresses the coil spring 27 by this amount and moves inward, giving an inconvenient thrust load to the lathe spindle, chuck to be measured, measuring device, etc. There will be no. Furthermore, when the chuck is rotated at high speed from the grasped state, the chuck will further float due to the centrifugal force exerted on itself, increasing the degree of tip opening and displacing the measuring instrument.
Shifts to absorb the movement, so there is no undesirable thrust load acting on the lathe spindle, chuck to be measured, measuring instrument, etc.

In addition, in the case of the one shown in the above embodiment, the detection part C
The rotary relay section A can be separated by the couplings 8, 9 and the connector 10, so that it can be used to measure the gripping force while the chuck is rotating, as well as for measuring the gripping force when the chuck is stationary, thereby eliminating the need for an unnecessary rotary relay. By removing part A, the output connection line to the display e can be directly connected to the connector 10.

FIG. 5 shows another embodiment of this invention, in which the same members as in the previous embodiment are given the same numbers and their explanations will be omitted.

In this embodiment, the end of the rotating shaft 11 extends into the hole 30 of the casing D of the rotary relay A, and a compression coil spring 27 is disposed in the hole 31 at the end of the rotating shaft 11. , a core support shaft 34 having a spring hole 33 in the hole 31 is provided so as to be slidable within a range where it abuts on the tail presser bearing 35, and the center of the shaft on the outer end surface side of the core support shaft 34 is provided with the above-mentioned implementation. As in the example, the center g of the tail stock f of the lathe is
A center hole 36 is provided for support.

The installation of the above-mentioned item on the lathe is exactly the same as in the previous embodiment, and after installation, the center g of the tail stock f is inserted into the center hole 3.
5, the compression coil spring 27 can be maintained in a preloaded state.

In addition, the center holes 29, 36 of the support shafts 24, 34
may be made to correspond to the shape of the tip of the center g of the tail stock f, or conversely, it may be, for example, a center protrusion.

This invention is constructed as described above, and by supporting the measuring instrument with the chuck yaw and the tailstock shaft of the tailstock, it is possible to prevent the center of rotation of the chuck from misaligning with the axis of rotation of the measuring instrument. Furthermore, since the measuring instrument does not shake during the measurement, the measurement work is safe.Furthermore, even if the chuck is displaced during high-speed rotation measurement, this displacement is absorbed by the compression coil spring, which is the biasing member. It has excellent effects such as being able to carry out measurement work safely.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing a state in which a conventional measuring instrument is attached to a work plate, Fig. 2 is a longitudinal sectional front view showing an embodiment of the measuring instrument according to the present invention, and Fig. 3 is a view taken from arrow B in Fig. 2. FIG. 4 is a sectional view taken along the line -- in FIG. 2, and FIG. 5 is a longitudinal sectional front view showing another embodiment. 1...Detection button, 2...Strength shaft,
3... Support button, 4... Strain gauge, 8,
9... Coupling part, 10, 21... Connector, 11... Rotating shaft, 13... Slip ring,
18... Brush, 22, 35... Core support bearing, 2
3... Guide hole, 24, 34... Core support shaft, 25...
... Small hole, 26 ... Shaft stem, 27 ... Compression coil spring, 28 ... Nut, 29, 36 ... Center hole,
30, 31, 32...hole, 33...spring hole.

Claims (1)

[Scope of utility model registration request] A detection part that is gripped by a chuck of a machine tool and rotates together with the chuck, and has a detection member inside that detects the gripping force of the chuck and emits a signal, and is detachable from the detection part and has a detection member that detects the gripping force of the chuck and outputs a signal. a rotary relay section that transmits the information to the display section, and a support shaft that engages with the center of the tail stock of the machine tool is provided on the opposite side of the rotary relay section from the detection section, the axis of which is aligned with the rotational axis of the chuck. Measuring gripping force of a chuck for a machine tool, characterized in that the chuck is disposed so as to be movable in the axial direction while being aligned with each other, and is further provided with a biasing member that biases the support shaft toward the center side. vessel.