JPH01295713A - In-process measuring method and device for thread shaft effective diameter - Google Patents

Abstract

PURPOSE:To contrive the improvement of grinding accuracy by connecting a probe to grinding tool supporting bed on a workpiece thread shaft to be integrally formed, bringing the probe into contact with a thread groove delayed by a half lead from a grinding point during grinding of the thread shaft, measuring the displacement and controlling a depth of cut. CONSTITUTION:A workpiece 3 is rotatably supported to and rotated on a table 2, grinding a thread with a grinding wheel 6 by moving the table 2. A probe 8 is connected to a grinding wheel bed 5 with an air cylinder 12 by a probe positioning one-axis table 11 and a turning plate 30, and grinding and measurement are performed from both sides of the workpiece 3 by the grinding wheel 6 and the probe 8. The table 11 is movable in the longitudinal direction. During grinding of a thread groove in the workpeice 3 by the grinding wheel 6, the probe 8 inserts its contact piece to be brought into contact with a thread groove delayed by a half lead from the groove during grinding by controlling the table 11 in the longitudinal direction, and the difference of a thread shaft effective diameter is measured. And being based on the difference, the grinding wheel 6 corrects its depth of cut.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention measures the effective diameter of a screw shaft during grinding of the screw shaft, and measures the effective diameter of the screw shaft to control the cutting feed of a processing tool during machining operation. The present invention relates to an in-process measuring method and an in-process measuring device used to carry out the measuring method.

[Prior art]

To measure the effective diameter of a screw shaft such as a lead screw or ball screw used in various feeding devices, conventionally, both ends of the screw shaft are supported horizontally, and two contacts are manually inserted from the diametrical direction into the flanks of the screw groove. There is a method of measuring by applying it to the surface, but this is a manual measurement and is inefficient, causes artificial variations in precision, and is highly tiring for the worker.

Examples of methods aimed at automating the measurement of the effective diameter of screw shafts include Japanese Patent Application Laid-Open No. 1983-1989. Publication No. 26202 or Japanese Unexamined Patent Publication No. 6
A device disclosed in Japanese Patent No. 2-54102 is known.

In the former, a U-shaped gauge body is provided so as to straddle a screw shaft to be measured whose both ends are supported horizontally, and a measuring device consisting of a detector and an anvil is attached to both ends of the gauge body. A spherical contact at the tip of is brought into contact with both flanks of the screw shaft with a predetermined pressure, and the effective diameter of the screw shaft is automatically measured by rotation of the screw shaft and relative movement of the gauge body in the direction of the screw ring axis. .

The latter measuring device of JP-A No. 62-54102 similarly has a measuring device attached to both ends of a U-shaped gauge body so as to straddle the screw shaft to be measured, and the lead angle of the screw shaft is attached to the gauge body. The degree of freedom in three directions corresponding to the change in lead amount, change in lead amount, and change in shaft deflection is provided, and the degrees of freedom in at least two of the three directions are perpendicular to the screw axis and approximately 90 degrees to each other. It is constructed by giving a degree of freedom by turning around two axes of the three axes, ie, two axes forming a shape, and an axle parallel to the screw shaft.

[Problem to be solved by the invention]

The above-mentioned conventional automatic screw shaft effective diameter measuring devices all measure the screw shaft that has been processed by attaching it to the support mechanism of a measuring device separate from the processing device for the purpose of inspection. It is difficult to immediately reflect the results in the groove machining of the screw shaft. That is, these measuring means are two-point measurements in which the screw shaft is clamped in the diametrical direction with a pair of probes, as in the case of manual measurement, and the structure is complicated and large in order to provide three degrees of freedom. Even when processing equipment and measuring equipment are used together, it is difficult to place the measuring equipment near the processing tool, and in this respect, so-called in-process measurement, which measures the effective diameter of the thread shaft while processing the thread groove, is difficult. There are problems in applying it.

The present invention uses a single gauge head and arranges it on the opposite side of the machined screw shaft from the machining tool, so that the machine tool and the gauge head sandwich the machined screw shaft, which reduces space constraints. An object of the present invention is to provide a measurement method and an in-process measurement device that enable in-process measurement without being subjected to turbulence.

[Means to solve the problem]

In the in-process measuring method of the effective diameter of a screw shaft according to the present invention, a measuring element is connected to and integrated with a support base of a processing tool for a screw shaft to be machined, and a half-lead from the processing point of the screw shaft is carried out during machining of the screw shaft. The measuring element is brought into contact with the delayed thread groove to detect its displacement, and the depth of cut of the processing tool can be controlled based on this displacement signal.

Further, the screw shaft effective diameter measuring device according to the present invention is pivotably mounted on a processing tool support stand of a screw shaft to be machined so as to straddle the screw shaft, and is capable of rotating within a plane perpendicular to the axis of the screw shaft. an l-axis table for positioning the probe, a drive device for rotating the single-axis table for positioning the probe above the screw shaft, and a screw groove that is delayed by half a lead from the processing point of the screw shaft relative to the processing tool. an elastic support mechanism that connects the measuring element to the single-axis table for positioning the measuring element so as to be able to elastically displace the measuring element in the axial direction of the screw shaft and in the horizontal direction perpendicular thereto; and an arithmetic processing device that calculates a correction value for the depth of cut of the machining tool from the displacement of the child.

〔Example〕

Next, the invention will be explained by way of example with reference to the drawings.

FIG. 2 is a schematic perspective view from the front side of an embodiment in which the present invention is applied to a screw grinder, and FIG. 1 shows an in-process measuring device for the effective diameter of a screw shaft according to an embodiment of the present invention. , is a side view shown during the measurement and grinding operation.

As shown in Fig. 2, a screw shaft (workpiece) 3 for grinding a thread groove and measuring its effective diameter is mounted on the headstock 4 of a table 2 that reciprocates left and right on the main body (bed) 1 of the grinder. A grindstone stand 5 is supported horizontally at both ends and has a grindstone shaft supported on the bed 1 side.

A measuring element 8, which will be described later, is arranged on the opposite side of the grinding wheel 6 by approximately 180 degrees across the workpiece 3, that is, on the front side of the bed 1. The measuring stylus 8 is connected to the grinding wheel 5 by a one-wheel table 11 for positioning the measuring stylus and a rotating plate 30.
With the workpiece 3 sandwiched between both sides of the workpiece 3 and the probe 8, the workpiece 3 is rotated and the workpiece is ground and the effective diameter of the thread is measured.

Fig. 3 is an enlarged side view of section A in Fig. 1, Fig. 4 is a front view seen from arrow F in Fig. 3, and Fig. 5 is an enlarged side view of section A in Fig. 4.
FIG. The supporting structure of the probe 8 will be explained in detail with reference to the first article and FIGS. 3 to 5. A pivot plate 30 is mounted on the front part of the grinding wheel head 5 which pivotally supports the grinding wheel 6 so as to be close to the side surface of the grinding wheel 6 and to straddle the workpiece 3.
The whetstone head 5 is pivotably mounted so as to be pivotable upward about the i30a, and an air cylinder device 12 is pivotably mounted to the upper part of the whetstone head 5. The tip of the piston rod 13 of the air cylinder device 12 is pivotally attached to the back (upper part) of the rotating plate 30, and the l-axis table 11 for positioning the probe is fixed to the side of the rotating plate 300. As will be described later, a measuring element 8 is attached to the measuring element positioning l-axis table bow l in an elastically supported manner. Swivel plate 3 is activated by air cylinder 11F12.
0 can be pivoted while holding the probe 8 from the measurement preparation position shown in FIG. 6(b) to the retracted position during non-measurement shown in FIG. 6(a). Reference numeral 14 denotes a stopper for positioning when the rotating plate 30 is lowered to the measurement position, and is adjustable on the grindstone head 5. The l-axis table 11 for measuring probe positioning attached to the rotating plate 30 is controlled by a pulse motor 33 from the measurement start position shown in FIG. .

The l-axis table 11 for positioning the measuring head has a l-axis for positioning.
A vertical slide block 1 that is movable vertically through the axis table 11, that is, movable vertically in the measurement operation position of the positioning l-axis table 11;
5 is provided, and at the bottom of this vertical slide block 15, there are provided an extension direction of the probe positioning l@tadale 11,
In other words, a front-rear slide guide 5916 that is horizontally movable in the front-rear direction of the grinding machine is provided, and this front-rear slide block 16 is further provided with a left-right slide block 17 that is movable horizontally in the extension direction of the workpiece, that is, in the left-right direction of the grinder.
is provided. These slide blocks 15,1
6.17 can be moved in each of the above-mentioned directions by a known manual screw feeding mechanism, and can be clamped at a predetermined position by tightening a bolt.

15a is a vertical feed screw in that case, 15b is a vertical clamp bolt, 16a is a longitudinal feed screw, 16b
17a is a front-rear clamp bolt, 17a is a left-right feed screw, and 17b is a left-right clamp bolt.

Referring to FIG. 4 and FIG. 5, the probe positioning l
A bracket is fixed to the lower surface of the shaft table 11 adjacent to the slide block, and a probe positioning proximity switch 19 is attached to the tip (lower end) of the bracket foot 18. The bracket lift 18 is divided into three parts and connected together, and the position can be adjusted in the vertical, horizontal, and front-back directions. The proximity swing 19 is a measuring element 8 which will be described later.
The lower portions of the left and right slide blocks 17, which are installed adjacent to and at approximately the same height position and whose position is adjustable in the front and back direction with respect to the bracket 18, are partially exposed from the slide guides 17c, and this exposure A pair of parallel plate springs 20 for floating the probe are connected to the lower portions of the left and right slide blocks so as to extend vertically downward, the plate surfaces of which are oriented in the length direction of the workpiece 3 (FIG. 1). A floating block 21 is fixed to the lower end of this parallel plate spring 20, and a pair of plates for small displacement in the measurement direction that similarly extend vertically downward and face the front surface of the grinding machine are attached to the floating block 21. A parallel leaf spring 22 is fixed.

As best shown in FIG. 3, a measuring element 8 having a contact piece 8a at its tip is fixed horizontally to the lower part of the parallel plate spring 22 for minute displacement in the measurement direction.

The contact piece 8a of the measuring stylus 8 is formed in such a shape and shape that it can contact the thread groove flank of the screw shaft (workpiece) 3 to be measured with an appropriate measurement pressure due to the spring force of the parallel leaf spring 22. For example, when the screw shaft 3 is a ball screw shaft, it is composed of carbide balls of the same size as the balls incorporated in this ball screw device. The rear end of the measuring head 8 is
It comes into contact with the electric micrometer 24 held on the bracket 23 fixed to the support part of the parallel plate spring 20 of the left and right slide block 17, and thereby the front-back displacement of the contact piece 8a at the tip of the probe changes to the electric micrometer 24. is retrieved via. Note that the contact 8a is at an angle of 180° (half lead) from the grinding point of the workpiece 3 by the grinding wheel 6.
The parallel plate spring 20 for floating the measuring head, which is in a position perpendicular to the parallel plate spring 22 that contacts the thread groove of the screw shaft at a delayed position and applies the measuring pressure, measures the drunken walking of the workpiece 3 during grinding. The measuring element 8 is supported in a floating manner so as not to affect the contact element 8a, so that the displacement of the contact element 8a in the left-right direction (in the direction of the threaded ring axis) is absorbed by the parallel plate spring 20, and only the radial displacement of the workpiece 3 is absorbed. is measured.

Next, the in-process measurement operation of the screw shaft 3 using the measuring device having the above configuration will be explained. First, before grinding the screw shaft and measuring the growth diameter, set the slide block 1 in the state shown in Fig. 6 (C).
5, 16. Using 17, move the probe in the height direction, front and back direction,
The positional relationship between the proximity switch 19 and the probe 8 is set so that the contact piece 8a lightly contacts the thread groove of the screw shaft 3 by adjusting in the left-right direction. After this adjustment, -1
The shaft table 11 is brought to the measurement preparation position shown in FIG. 6 (b), and then returned to the retracted position shown in FIG. When grinding is started, the position is confirmed by the grinding machine table position detection switch 31 (Fig. 2) which engages with the dog 32 of the workpiece feed table 2 of the grinding machine (Fig. 2), and then from Fig. 6 (a) The movement from FIG. 6(C) to FIG. 6(C), which is performed from FIG. When the probe positioning proximity switch 19 detects the outer diameter of the screw shaft 3, the single-axis table 11 stops. Even if there is a slight variation in the cutting feed rate of the grinding wheel 6, a variation in the amount of grinding due to a sloppy step of the screw shaft 3, or a bending of the screw shaft, the contact point will be held against the screw shaft by the aforementioned parallel plate springs 20 and 22. Since the contact piece 8a is pressed, the contact piece 8a does not separate from the thread groove of the screw shaft 3. The displacement of the probe 8 due to the contact of the contact piece 8a is detected by an electric micrometer, and the displacement of the probe 8 is detected by an electric micrometer. Processing device 2 via A/D converter 25
6, the discrepancy in the effective diameter of the screw shaft is calculated, a correction command for the depth of cut of the grindstone head is output, and the measurement results are displayed on the CR7 display section 27 and the plotter 28. In this case, the correction amount is stored using the data immediately after the start of measurement as a reference value, and compared with the measured values that are taken in sequentially, the grinding head cutting feed pulse motor is controlled. When the grinding wheel is corrected and one stroke of grinding is completed, the L-axis table 11 for positioning the measuring tip that holds the measuring tip retreats, and at the same time, the entire table rotates upward and retreats (Fig. 6(a) = (b) = (C ), and after confirming the position again using the table position detecting proximity switch 31, the operations shown in FIGS. In this way, in-process measurement is performed on the workpiece processing machine, and feedback measurement and processing for correcting discrepancies in effective diameter are possible based on the measurement data.

〔Effect of the invention〕

As explained above, according to the present invention, the machining tool becomes equivalent to one of the contacts in contact with the object to be measured, and the tool and
It is only necessary to apply the other contact to the opposite position of 80", which simplifies the structure, reduces space constraints, and enables in-process measurement.The contact itself is a flexible parallel 2
Since it is supported by a combination of leaf springs, it follows the workpiece in the axial direction and front-back direction without resistance, and the tip of the probe has little wear and does not damage the workpiece. By using this device, it is possible to grind while measuring the effective diameter during machining, which contributes to improving the dimensional accuracy of the screw shaft, and also allows for rework by measuring the workpiece after machining, as in Reina's grinding. Since it is not necessary to carry out grinding under such conditions, grinding efficiency is improved, which also leads to cost reduction.

[Brief explanation of the drawing]

Fig. 1 is a side view of an in-process measuring device for the effective diameter of a thread according to an embodiment of the present invention, and Fig. 2 is a schematic partially cutaway perspective view of an embodiment in which the present invention is applied to a thread grinder. , Fig. 3 is an enlarged side view of section A in Fig. 1, and Fig. 4 is an enlarged side view of section A in Fig. 3.
FIG. 5 is a front view seen from the side, and FIG. 6(a) is a side view seen from arrow G in FIG. 4. Φ) and (C) are side views for explaining the operation of the rotating plate and the single-axis positioning table. 3...Screw shaft (work), 5...Wheelhead, 6...
Grinding wheel, 8... Measuring head, 8a... Contact piece, 11...
・Single-axis table for measuring probe positioning, 12...Air cylinder LI! , 15... Vertical slide block, 16... Front and rear slide block, 17... Left and right slide block, 18.23... Frakent, 19... Proximity switch for positioning probe, 20...
Parallel plate spring for floating gauge head, 21... Floating link, 22... Parallel plate spring for minute displacement in measurement direction, 24... Electric micrometer, 25... A/D converter, 26...・Arithmetic processing unit, 3
0...Swivel plate, 31...Sinch for detecting the position of the grinding machine table.

Claims (2)

[Claims] (1) Connect the gauge head to the support base of the machining tool of the screw shaft to be machined and integrate it, and during the machining of the screw shaft, contact the gauge head with the thread groove that is delayed by half a lead from the machining point of the screw shaft. 1. An in-process measuring method for an effective diameter of a screw shaft, the method comprising: detecting the displacement of the machining tool; and controlling the depth of cut of the machining tool based on the displacement signal. (2) a single-axis table for positioning a probe, which is pivotally mounted on a machining tool support for a screw shaft to be machined so as to straddle the screw shaft, and is rotatable in a plane perpendicular to the axis of the screw shaft;
a driving device for rotating the one-axis table for positioning the measuring element above the screw shaft; and a measuring element arranged to contact a thread groove delayed by half a lead from the processing point of the screw shaft with respect to the processing tool. an elastic support mechanism that connects the gauge head to the single-axis table for positioning the gauge head so as to be able to elastically displace the gauge head in the axial direction of the screw shaft and in a horizontal direction perpendicular thereto; 1. An in-process measuring device for the effective diameter of a screw shaft, comprising: an arithmetic processing device that calculates a correction value for the depth of cut of a tool.