JPS58186525A - Error corrector of thread pitch diameter in thread grinding machine - Google Patents

Abstract

PURPOSE:To automatically correct an error of a thread pitch diameter at grinding, by providing a control unit, which performs sequence control of a switch circuit with a digital signal of a counter to supply a correction signal to a pulse motor, to facilitate centering work. CONSTITUTION:A work 19 is supported by a main spindle 17 of a main spindle bed 15 and a tailstock spindle 18 of a tailstock 16. A position detector 31 detects a moving position of a moving bed 14, and a detected signal of the detector 31 is converted into a digital signal by a counter 32. A grinding wheel bed 27 performs feed cutting by a pulse motor 28 through a feed screw 29, and a correction signal is supplied to the motor 28 by a control unit 34. On the basis of a corrective amount preset to a toggle switch 36 of a thread pitch diameter error corrector unit 33, an output signal from a switch circuit is fed to the motor 28 through the unit 34 to drive the motor 28, and a corrective amount of feed cutting is given to control the bed 27 through the feed screw.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a screw grinding method 111 for grinding a thread groove of a screw shaft in a ball screw, etc., and a screw effective diameter that automatically corrects the thread effective diameter error of a thread groove in % during grinding. This relates to an error correction device.

Figure 1 shows a conventional general example of grinding the thread grooves on the screw shaft of a ball screw, where l is the screw shaft, 2 is the thread groove on the screw shaft l, and 3 is the outer diameter direction of the screw shaft l. be. screw shaft l
When grinding the thread groove 2 of For example, grinding is performed while being supported by steady rests 6a and 6b at two locations. However, when the screw shaft l is long or has a small shaft diameter, the bending of the screw shaft l due to its own force, or the effect of the grinding force when grinding the two surfaces of the thread groove. Therefore, the effective thread diameter of the thread groove 2 after grinding has a dimensional difference due to the axial position tkK of the screw shaft 1, and the axial locus of the effective thread diameter is like the curve 7 shown by the imaginary line. Generally, when a ball screw is used with a fixed position preload type, the preload of the ball screw fluctuates due to the influence of the pitch error of thread groove 2 of the screw shaft as well as the error of the effective thread diameter of thread groove 2. Fluctuations in the preload of the ball screw affect the fluctuations in the friction torque of the ball screw, which is a factor that reduces the function of the ball screw.Therefore, in order to obtain a high-precision ball screw, the thread groove of one screw shaft must be In order to perform grinding so that the mutual difference in the effective diameter of the screw is small, it is necessary to perform rough grinding several times as necessary before finishing grinding. It was necessary to fine-tune the steady rest 61.6b and the tailstock shaft 5 to center the screw shaft l.This centering work needs to be performed in micron units, so it requires a high level of skill. However, there were drawbacks such as the fact that the adjustment required a lot of time.

The present invention is intended to solve the above-mentioned drawbacks, and includes a main body,
A screw grinding machine that has a grinding wheelhead feed mechanism that is provided on the main body and whose cutting feed is controlled by a pulse motor, and a movable table that is attached with a headstock and tailstock that supports the workpiece and is movable on the main body. , a position detector that detects the position of the moving table in the main body, a counter that converts the detection signal of this position detector into a digital signal, and a plurality of The screw effective diameter correction section has a switch circuit, and the switch circuit is sequence-controlled by the digital signal pressure of the counter.
By equipping the pulse motor with a control unit that supplies correction signals, it is extremely easy to center the workpiece, and it is also possible to automatically correct errors in the effective thread diameter of the workpiece during grinding. It is an object of the present invention to provide a screw effective diameter difference correcting device for screw grinding and high efficiency.

Embodiments of the effective screw diameter error correction device for a screw grinder according to the present invention will be described below with reference to the drawings.

In FIG. 2, 11 is a thread grinder, 12 is a main body of the thread grinder 11, and the main body 12 includes a grindstone head feeding mechanism 13 and a movable table 14 that slides on the main body 12 and moves in the direction of lateral force. It is provided. The moving table 14 has a headstock 15 and a tailstock 1.
6 is attached, and a trap is formed such that both ends of the workpiece 190 are supported by the main shaft 17 of the headstock 15 and the tailstock shaft 18 of the tailstock 16. Outer diameter surface 2 of workpiece 19
+J is a plurality of steady rests 21 attached to the moving table 14
a, 21b K. The moving table 14 is moved by a lead screw feeding mechanism 22, and the lead screw feeding mechanism n has a lead screw n and a nut screwed onto the lead screw, and one end of the lead screw is connected to the main shaft 17 by a gear. They are connected in row 6, and a moving base 14K is added at the other end, and a nut 24 is provided on the main body 12K[iN]. The grinding wheel head feeding mechanism 13 includes a grinding wheel head Z that supports the grinding wheel.
The grinding wheel head r can be fed into the cut via a feed screw 4 by means of a pulse motor path. Movable table 14 K 4'! A scale plate is attached, and the scale plate 30 has scales at regular intervals of, for example, 59 mm, and each scale is marked with a serial number (not shown) from the reference point. In the reference numerals in the figure, 31 is a position detector, which is a detector that can detect the rotational speed of a lead screw, for example, and detect the moving position of the movable base 14 with respect to the main body 12. It is a counter that converts the detection signal into a digital signal, and is a control section that supplies a correction signal to the pulse motor path. As shown in FIG. 3, a plurality of toggle switches I are added to the panel 35, and the screw effective diameter error correction section has a plurality of toggle switches I added to the panel 35.
They are arranged at the positions of l, . . . Sn.

As shown in Fig. 4, each toggle switch 36 has a switch lever 37 that can be shifted to the upper, neutral, and lower positions. It has a switch circuit that can output a correction signal.

4. The operation of the apparatus of the present invention configured as in 5 above will be explained. First, both ends of the workpiece 19 are supported by the main shaft 17 and the tailstock shaft IBK, and the outer diameter of the workpiece 19 is supported by the steady rests 21a and 21b provided on the moving table 14. The steady rests 21a and 21b are respectively bent to reduce the deflection due to their own weight.

Next, at the axially inner position ft of the workpiece 19, which corresponds to the extension line of each scale marked at regular intervals on the scale plate 31) provided on the moving table 14, the thread of the thread groove before grinding is effective. Measure in advance using a measuring device such as a diameter bassometer. Next, a cutting correction amount for the cutting feed gradation of the magnet base n is set based on the measured value of the effective thread diameter of the thread groove before the grinding process by each measuring device tlltK in the axial direction of the workpiece 19. The method of setting 2 of this correction will be explained with reference to FIG. Shift the switch lever 37 of the S1 position toggle switch arranged on the panel 35 upward (+l till K) corresponding to the scale lK on the scale plate side of the moving base and the corresponding scale number on the scale plate side. At correction position 2, if it is necessary to correct the unit correction amount for the correction position lVc, shift the switch lever 37 of the toggle switch in the S position on the panel to the (A) side.In this way, the workpiece is Set the correction amount for each correction amount by shifting the switch lever 37 of the toggle switch I arranged on the corresponding panel 35 and corresponding to the correction position INK of object 19 to any of the positions [K], (0), and H [K]. The unit correction amount can be selected, for example, by providing a digital switch (not shown) in the control unit 34 that can be arbitrarily selected from 1 to 1()μ.Next, the workpiece 1
After setting the correction lid for each correction amount [K] of 9 using each toggle switch of the screw effective diameter error correction section, the automatic grinding cycle of the screw grinder 11 is started. Next, when the automatic grinding cycle is started, the position detector 31 converts the position of the movable table 14 with respect to the main body 12, that is, the abrasive signal Kf, and supplies it to the control unit 34.

A signal that is sequence-controlled by the control section according to the output signal of the counter 32 is supplied to the screw effective diameter error correction section 33,
The switch circuit of the toggle switch of the screw effective diameter error correction section corresponding to the moving position of the moving table 14 detected by the position detector 31 is activated. An output signal from the switch circuit is supplied to the pulse motor 28 as a correction signal via the control section after setting the error correction section to the toggle switch 36 in advance. is driven, and a correction cover for the cutting feed is applied to the grindstone head υ via the feed screw to control it.

The screw effective diameter error correction device for the screw grinding machine of the present invention described above includes a main body, a grindstone feed mechanism provided in the main body and whose cutting feed is controlled by a pulse motor, a headstock and a center that support a workpiece. A screw grinding machine with an additional push shaft and a movable table movable on the main body has a plurality of switch circuits capable of determining the shift in the main body and the pre-measured cut correction cover of the workpiece. The centering work of the workpiece before the grinding process is achieved by providing a screw effective diameter error correction section having a screw diameter error correction section, and a control section that sequentially controls the switch circuit using the digital signal of the counter to supply correction signals to the russ motor. This method is extremely easy compared to the conventional method, and the machining error of the effective thread diameter of the workpiece is determined by setting the cutting depth correction amount of the grindstone based on the measurement value measured before the start of the grinding process. Since the correction is made in-house, it is significantly improved compared to the conventional method, and it is possible to perform grinding processing with small differences in the effective thread diameter of the workpiece, and the time required for centering adjustment of the workpiece is shortened. , effects such as improved work efficiency can be obtained.

[Brief explanation of the drawing]

Figure 3 is an explanatory diagram when the workpiece is a screw shaft of a ball screw, and Figures 2 to 4 show the effective screw diameter correction device in the screw grinding machine of the present invention. The figure is a plan view, FIG. 3 is a front view of the screw effective diameter error correction section, and FIG. 4 is an explanation of the symbols 12...main body, 13... ... Grindstone feed mechanism, 14... Moving table, 15... Axis table, 16... Tailstock, 19... Workpiece, A...Pulse motor, 31...Position detector, 32...Counter, O...Screw effective diameter error correction section, 34......・Ichirijo Section License Applicant: Nippon Choko Co., Ltd.

Claims (1)

[Claims] +11 A main body, a grindstone head feeding mechanism provided in the main body and whose cutting feed is controlled by a pulse motor,
A screw grinding machine having a headstock and a tailstock for supporting a workpiece and a movable base movable on the main body, a position detector for detecting the position of the movable base on the main body; a counter that converts a detection signal of a position detector into a digital signal; a screw effective diameter error correction section having a plurality of switch circuits capable of setting a pre-measured cutting depth correction amount of a workpiece; and a digital signal of the counter. A control unit 11 for sequentially controlling the switch circuit and supplying a correction signal to the pulse motor.