JPH10111122A - Device for measuring screw of ball screw unit and nut measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide ball screw unit measuring technology which is simpler than a three-dimensional measuring device and can be measured efficiently. SOLUTION: A screw measuring device 1 is constituted of a work support block 3, first to third measuring pins 27, 29, 31 bitten to a screw W1, a y-axis scale 17 for measuring the position of the first measuring pin 27, an x-axis scale 6 for measuring the position in the direction of the screw shaft of a first slider 5 collectively mounting the y-axis scale 17 and the first to the third measuring pins 27, 29, 31 and a calculator 25 for calculating on the basis of the position information from the x-axis scale 6 and the y-axis scale 17. The center diameter of a ball can be measured by the first to the third measuring pins 27, 29, 31, the y-axis scale 17 and the calculator 25. A lead can be measured by the first and second measuring pins 27, 29 except for the third measuring pin 31, the x-axis scale 6 and the calculator 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring the diameter and pitch of a ball screw unit comprising a screw, a nut and a ball.

[0002]

2. Description of the Related Art A ball screw unit in which a ball is interposed between a screw and a nut has a low friction torque, and is widely used in precision machinery. It is indispensable to measure the finishing accuracy of the screws and nuts for that purpose.

FIG. 13 is an explanatory view of a conventional three-needle method for measuring the diameter of a ball screw. One of the methods for measuring the ball center diameter of the screw 101 of the ball screw unit is as follows. Three pins 102 having the same diameter as the ball are prepared, and these pins 102...
Measure the outer dimensions with. By subtracting the diameter of the pin 102 from this outer dimension, the ball center diameter of the screw 101 is obtained.

The above three-needle method is a widely used method for determining the nominal diameter of a screw, but requires skill in handling the bottles 102... For this reason, it is difficult to improve the efficiency of the measurement operation and ensure the measurement accuracy. And you can't measure leads,

[0005] Therefore, for example, adoption of a three-dimensional measuring device disclosed in Japanese Patent Publication No. 2-61684 "3D surface shape measuring device" can be considered. This three-dimensional measuring device is a device that scans a measuring needle along an object to be measured, and measures and stores (x, y, z) coordinates of a number of points to obtain a shape and an outline. The center diameter and lead can be calculated.

[0006]

However, the above three-dimensional measuring device is a high-precision measuring device that is too expensive to measure the center diameter of the ball and the lead, and has a problem that the measuring time is long and the working efficiency is poor. is there. Therefore, an object of the present invention is to provide a measurement technique which is simpler than a three-dimensional measuring device and can measure efficiently.

[0007]

According to a first aspect of the present invention, there is provided a work support block for supporting a screw of a ball screw unit, wherein one of the supported screws is engaged by a three-needle method. A first measuring pin, a second measuring pin also engaged with the other side of the screw, a third measuring pin which is similarly engaged with the other side of the screw and detachable, and a screw shaft based on the second measuring pin. A y-axis scale for measuring the position of the first measurement pin in a right angle direction, and an x-axis scale for measuring the position in the screw axis direction of the first slider on which the first to third measurement pins are collectively mounted. And a calculator for calculating the ball center diameter or lead of the screw based on position information from the x-axis scale and the y-axis scale. Constitute a screw measuring device of Tsu door.

[0008] The first to third measurement pins, the y-axis scale, and the calculator can measure the ball center diameter of the screw. Except for the third measuring pin, the first and second measuring pins, the x-axis scale, and the calculator can measure the lead of the screw. Therefore, the center diameter and lead of the screw can be measured with a device much simpler than a three-dimensional measuring device, and the measuring time is shortened, and the work efficiency is increased. Further, since no human reading error is involved, the reliability of the measured value is improved.

A second aspect of the present invention provides a nut support block for supporting a nut of a ball screw unit, a nut measuring head having a pair of hemispherical members that bite into the screw of the supported nut projecting from each other in a direction perpendicular to the axis of the nut. An x-axis scale that measures the position of the nut measuring head in the direction perpendicular to the axis of the nut, a y-axis scale that measures the position of the nut measuring head in the axial direction of the nut, and a nut based on position information from the x-axis scale and the y-axis scale And a calculator for calculating the ball center diameter or lead of the nut.

The hemispherical member is moved in the x and y directions and pressed against the thread valley of the nut, the coordinates at that time are stored, and the arithmetic unit calculates the ball center diameter or lead. Therefore, the ball center diameter and the lead of the nut can be measured by a device much simpler than the three-dimensional measuring device, and the measuring time is shortened, and the work efficiency is improved. Further, since no human reading error is involved, the reliability of the measured value is improved.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings should be viewed in the direction of reference numerals. FIG. 1 is a plan view of an apparatus for measuring a ball center diameter and a pitch of a screw of a ball screw unit according to the present invention. Note that, as shown in the figure, the left-right direction in the figure is called the x direction, and the up-down direction is called the y direction. A screw ball center diameter and pitch measuring device 1 (hereinafter, abbreviated as “screw measuring device 1”) is provided with a pair of work support blocks 3 on a bed 2 and a first slider via rails 4. 5 is movably mounted in the x direction, the measuring head 7 of the x-axis scale 6 is connected to the first slider 5, and the second slider 12 is moved in the y direction on the first slider 5 via the rails 11, 11. One pin holder 13 is fixed to the second slider 12, and a third slider 15 is further mounted on the second slider 12 via the rails 14, movably in the y direction. The other pin holder 16 is fixed to the
The measurement head 18 of the y-axis scale 17 is connected to the slider 15. As shown, the one pin holder 13 and the other pin holder 16 are members arranged at positions sandwiching the work W1 from one side and the other side of the work W1.

Reference numerals 21 and 22 denote standby cylinders, reference numerals 23 and 24 denote springs.
The pin holder 13 can be pushed out to the screw W1 as a work via the spring 23 by moving the pin holder 2 to the standby position and extending the piston rod of the standby cylinder 21. The standby cylinder 22 also functions to push and pull the third slider 15. Numeral 25 denotes a calculator for calculating the ball center diameter or lead of the screw W1 based on the position information of the x-axis scale 6 and the y-axis scale 17.

FIG. 2 is a sectional view of the other pin holder of the screw measuring device according to the present invention.
Reference numeral 6 denotes a groove in which a first measuring pin 27 is fitted. The first measuring pin 27 is a precisely machined cylinder having the same diameter as the ball of the ball screw, and can move about several mm in the direction of the front and back of the drawing. .

FIG. 3 is an exploded perspective view of one of the pin holders of the screw measuring device according to the present invention. In one of the pin holders 13, semi-cylindrical recesses 28, 28 (one of which is inclined by the lead angle θ of the screw) are provided. (Not shown), a second measuring pin 29 is fitted on one side, integrated with the holder 19, and a third measuring pin 31 is detachably mounted on the other concave portion 28. For this purpose, the third measuring pin 31 is, for example, a cylinder 32 precisely machined to the same diameter as the ball of the ball screw unit.
And stud bolts 33 screwed into this cylinder 32
And nuts 34, 34. Note that the other pin holder 1 in FIG.
Attach to 6.

FIG. 4 is a diagram showing a relationship between a measuring pin and a work of the screw measuring device according to the present invention, and is a plan sectional view of a main part of FIG. When pressed against the root of the screw of the screw W1, the first measuring pin 27 does not move in the y direction because it hits the bottom of the groove 26 of the other pin holder 16, and can move about several mm in the x direction. The second measuring pin 29 is integrated with one of the pin holders 13, and the third measuring pin 31 is integrally fixed to the one of the pin holders 13 by tightening the nut 34. Therefore, the second and third measurement pins 29 and 31 do not move in the x direction. The distance L1 between the second and third measurement pins 29, 31 is the same as the lead of the screw W1.

The operation of the screw measuring device described above will now be described. The screw measuring device 1 can measure the ball center diameter and the lead of the screw. FIG. 5 is a flow chart for explaining the ball center diameter of the screw according to the present invention. Is shown. ST01: Move the second slider 12 downward in FIG.
Then, the third slider 15 is moved upward in the drawing. This operation corresponds to the movement to the standby position. ST02: A reference cylinder (a cylinder with no thread groove) is set on the work support blocks 3 and 3. ST03: Extrude the second slider 12 to the reference cylinder, and then extrude the third slider 15 to the reference cylinder. ST04: First, Second and Third Measuring Pins 27, 29 and 31
Against the reference cylinder.

FIGS. 6 (a) and 6 (b) are diagrams for explaining the measurement of the ball center diameter of the screw. The outer diameter D1 of the reference cylinder 36 is measured by the y-axis scale 17 in ST05 in the manner of (a). ST06: First, Second and Third Measuring Pins 27, 29 and 31
Is the diameter of d, the reference ball center diameter (D1-d) is obtained. This is stored. ST07: Put the second and third sliders 12, 15 on standby,
Remove the reference cylinder 36. The above steps ST01 to ST07 are the “calibration” step.

ST08: Screws to be measured are set on the work support blocks 3 and 3. ST09: Extrude the second and third sliders 12, 15 to the screws. ST10: First, Second and Third Measuring Pins 27, 29 and 31
Against the thread of the screw. ST11: Y-axis scale 17 as shown in FIG.
Is used to measure the ball center diameter D2 of the screw W1. ST12: Move the second and third sliders 12, 15 to the standby position. ST13: It is determined whether or not the number of measurements has reached a predetermined number N. If the number has been reached, the measurement is terminated, and if not, the process proceeds to ST14. ST14: The first slider 5 is moved by a necessary distance in the x direction, and the process returns to ST09 to repeat the measurement.

Next, a method for measuring the lead of the screw will be described. For this purpose, the third measuring pin 31 shown in FIG. FIG. 7 is a flowchart of the lead measurement of the screw according to the present invention. ST21: Examine the presence or absence of the third measurement pin 31. If you have
Remove it in ST22. ST23: Extrude the second and third sliders 12, 15 to the screws. FIGS. 8 (a) and 8 (b) are explanatory diagrams of lead measurement of a screw.
The first and second measuring pins 27 and 29 are pressed against the screw roots of the screw W1.

ST25: Calculate the ball center diameter D3 based on the measured value of the y-axis scale 17. ST26: This D3 should be the same as D2 obtained in ST11. Therefore, the difference between the two is obtained, and it is checked whether or not the difference is smaller than a small value α. If No, the first
Since there is a possibility that the second measuring pins 27 and 29 may not be set correctly on the screw W1, the cause is removed and the process is retried from ST23. If yes, proceed to the next.

ST27: The x coordinate of the second measuring pin 29 is set as the origin. ST28: Move the second and third sliders 12, 15 to the standby position. ST29: The first slider 5 is moved by one lead in the x direction. ST30: Extrude the second and third sliders 12, 15 to the screw. ST31: The first and second measuring pins 27 and 29 are pushed out into the screw roots of the screw. ST32: The ball center diameter D4 is calculated based on the measurement value of the y-axis scale 17.

ST33: This D4 should be the same as D2 obtained in ST11. Therefore, the difference between the two is obtained, and it is checked whether or not the difference is smaller than a small value α. If No, there is a possibility that the first and second measurement pins 27 and 29 may not be correctly set on the screw. Therefore, the cause is removed and the process is retried from ST30. If yes, proceed to the next. ST34: The x coordinate “x4” of the second measurement pin 29 is read.

As shown in FIG. 8B, the x coordinate "x4" is the distance from the origin and is a lead. This means that the lead at a certain location has been measured. ST35: Move the second and third sliders 12, 15 to the standby position. ST36: It is checked whether or not the number of measurements has reached a predetermined number M. If not, the process returns to ST29. ST3
7: After a predetermined number of measurements are completed, the screw W1 is removed.

FIG. 9 is a plan view of a nut measuring device according to the present invention. The nut measuring device 40 has a nut support block 42 on a bed 41 and rails 43 and 4.
3, an x-axis slider 44 is attached so as to be movable in the x-direction, a measuring head 46 of an x-axis scale 45 is connected to the x-axis slider 44, and a rail 4 is connected to the x-axis slider 44.
Y-axis slider 48 movably in the y-direction via 7, 47
, The measurement head 51 of the y-axis slider 49 is mounted on the y-axis slider 48, and the nut measurement head 60 is mounted on the y-axis slider 48. 52 is a cylinder, 53,
53 is a spring, and W2 is a nut. Numeral 55 denotes an arithmetic unit for calculating the ball center diameter or the lead of the nut W2 based on the position information of the x-axis scale 45 and the y-axis scale 49.

FIG. 10 is an enlarged view of a main part of the nut measuring head. The nut measuring head 60 has hemispherical members 62 and 63 protruding from the tip of a bar 61 in a direction perpendicular to the axis.
The hemispherical member 62 is precisely finished with the same radius R as the radius of the screw of the ball screw unit. The same applies to the hemispherical member 63. Assuming that the outer dimensions of the two hemispherical members 62 and 63 after attachment are L2, L2 =
A + 2R.

The operation of the nut measuring device having the above configuration will be described below. FIG. 11 is a nut measurement flowchart, and FIG.
(A)-(d) is operation | movement explanatory drawing of nut measurement. ST41: A reference cylinder (unthreaded hollow cylinder) 64 is set on the nut support block 42 in FIG. The internal diameter d1 of this reference cylinder is known. ST42: In FIG. 12A, the nut measuring head 60 is inserted into the reference cylinder 64, moved as indicated by the arrow, and the moving distance L3 is measured by the y-axis scale 49 in FIG. ST43: In FIG. 12A, d1 = (A + 2R)
Since + L3, A can be obtained by the calculation of A = d1-2R-L3. A corresponds to the ball center distance of the nut measuring head 60, and stores the ball center distance A of this jig. ST44: Remove the reference cylinder from the nut support block 42. Thus, the “calibration” step is completed.

ST45: The nut to be measured is set on the nut support block 42. ST46: The hemispherical member 62 is pressed against the thread valley of the nut W2 as shown in FIG. 12 (b). ST47: The coordinates of the center of the hemispherical member 62 at this time (x
(0, y0). ST48: In FIG. 12 (c), while moving the nut measuring head in the direction of the arrow (x
(移動 pitch movement in the direction). ST49:
The coordinates (x1, y1) of the center of the hemispherical member 62 after this are stored.

ST50: In FIG. 12 (d), the nut measuring head is moved in the direction of arrow (1 /
(2 pitch movement). ST51: The coordinates of the center of the subsequent hemispherical member 62 (x2,
y2) is stored. ST52: Based on the above data, ball center diameter of nut = | x0−x1 | + A, lead of nut = | y0
−y2 | A is the value stored in ST43. || is a symbol of an absolute value. ST53: The number of measurements is confirmed, and necessary measurements are performed by repeating ST48 to ST52.

In FIGS. 1 and 9, the standby cylinders 21, 22, 52 are eliminated, and the sliders 12, 1 are manually operated.
5, 48 may be moved.

[0030]

According to the present invention, the following effects are exhibited by the above configuration. Claim 1 is a work support block that supports the screw of the ball screw unit, a first measuring pin that bites into one side of the supported screw in a three-needle manner,
Similarly, a second measuring pin that is also engaged with the other side of the screw, a third measuring pin that is also capable of being engaged with and removed from the other side of the screw, and the first measuring pin in a direction perpendicular to the screw axis with respect to the second measuring pin. A y-axis scale for measuring the position of the measurement pin, an x-axis scale for measuring the position in the screw axis direction of the y-axis scale and the first slider on which the first to third measurement pins are collectively mounted, and an x-axis scale; An arithmetic unit for calculating the ball center diameter or lead of the screw based on the positional information from the y-axis scale constitutes a screw measuring device for a ball screw unit.

The first to third measuring pins, the y-axis scale, and the calculator can measure the center diameter of the ball of the screw. Except for the third measuring pin, the first and second measuring pins, the x-axis scale, and the calculator can measure the lead of the screw. Therefore, the center diameter and lead of the screw can be measured with a device much simpler than a three-dimensional measuring device, and the measuring time is shortened, and the work efficiency is increased. Further, since no human reading error is involved, the reliability of the measured value is improved.

A nut supporting block for supporting the nut of the ball screw unit, a nut measuring head in which a pair of hemispherical members which bite into the screw of the supported nut are mutually projected in a direction perpendicular to the axis of the nut, An x-axis scale that measures the position of the nut measuring head in the direction perpendicular to the axis of the nut, a y-axis scale that measures the position of the nut measuring head in the axial direction of the nut, and a nut based on position information from the x-axis scale and the y-axis scale And a calculator for calculating the ball center diameter or lead of the nut.

The hemispherical member is moved in the x and y directions and pressed against the thread of the nut, the coordinates at that time are stored, and the arithmetic unit calculates the ball center diameter or lead. Therefore, the ball center diameter and the lead of the nut can be measured by a device much simpler than the three-dimensional measuring device, and the measuring time is shortened, and the work efficiency is improved. Further, since no human reading error is involved, the reliability of the measured value is improved.

[Brief description of the drawings]

FIG. 1 is a plan view of a device for measuring the ball center diameter and pitch of a screw of a ball screw unit according to the present invention.

FIG. 2 is a sectional view of the other pin holder of the screw measuring device according to the present invention.

FIG. 3 is an exploded perspective view of one pin holder of the screw measuring device according to the present invention.

FIG. 4 is a view showing a relationship between a measuring pin and a work of the screw measuring device according to the present invention.

FIG. 5 is a flowchart for measuring the ball center diameter of the screw according to the present invention.

FIG. 6 is an explanatory view of measuring a ball center diameter of a screw.

FIG. 7 is a flow chart of a screw lead measurement according to the present invention.

FIG. 8 is an explanatory view of screw lead measurement.

FIG. 9 is a plan view of a nut measuring device according to the present invention.

FIG. 10 is an enlarged view of a main part of the nut measuring head.

FIG. 11 is a flow chart of nut measurement.

FIG. 12 is an explanatory diagram of an operation of nut measurement.

FIG. 13 is a diagram illustrating a conventional three-needle method for measuring the diameter of a ball screw.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Screw measuring device, 2 ... Bed, 3 ... Work support block, 5 ... First slider, 6 ... X-axis scale, 12
... second slider, 13 ... one pin holder, 15 ... third
Slider, 16 ... one pin holder, 17 ... y-axis scale, 27 ... first measuring pin, 29 ... second measuring pin, 31 ...
3rd measuring pin, 33, 34 ... bolt and nut as bolt structure of the 3rd measuring pin, 36 ... reference cylinder, 40 ... nut measuring device, 41 ... bed, 42 ... nut support block, 45 ... x-axis scale, 49 ... y-axis scale, 55 ...
Arithmetic unit, 60: nut measuring head, 62, 63: hemispherical member, 64: reference cylinder, W1: screw, W2: nut.

Claims (2)

[Claims] 1. A work support block for supporting a screw of a ball screw unit, a first measuring pin for engaging one side of the supported screw in a manner of a three-needle method, and similarly for engaging the other side of the screw. A second measuring pin, a third measuring pin which can be similarly engaged with the other side of the screw and can be removed, and a y-axis scale for measuring the position of the first measuring pin in a direction perpendicular to the screw axis with reference to the second measuring pin. The x-axis scale for measuring the position in the screw axis direction of the y-axis scale and the first slider on which the first to third measurement pins are collectively mounted, and position information from the x-axis scale and the y-axis scale. A screw measuring device for a ball screw unit, comprising: a calculator for calculating a ball center diameter or a lead of a screw. 2. A nut support block for supporting a nut of a ball screw unit, a nut measuring head in which a pair of hemispherical members that bite into the screw of the supported nut are projected from each other in a direction perpendicular to the axis of the nut, and a shaft of the nut. An x-axis scale that measures the position of the nut measuring head in the perpendicular direction, a y-axis scale that measures the position of the nut measuring head in the axial direction of the nut, and a ball center of the nut based on positional information from the x-axis scale and the y-axis scale. An arithmetic unit for calculating a diameter or a lead, and a nut measuring device for a ball screw unit.