JP2878956B2 - Method and apparatus for correcting bottom dead center position of cam press - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for correcting a bottom dead center position of a press machine, particularly a cam press having a structure in which a slide is moved up and down by a cam.

[0002]

2. Description of the Related Art Conventionally, the position of the bottom dead center of a slide in a mechanical press fluctuates due to the influence of thermal expansion and the like as the operation is continued. For example, JP-A-2-165900 and JP-A-5-185299 disclose devices for correcting the bottom dead center position.
There is a prior art known under the name No. The former is a device for correcting the position of the bottom dead center in a knuckle press, and as shown in FIG. 7, the position of the knuckle fulcrum shaft 101 can be displaced in the vertical direction, and the position of the bottom dead center of the slide 102 is changed. The position of the knuckle fulcrum shaft 101 is corrected. The latter is a device for correcting the position of the bottom dead center in the crank press machine. As shown in FIG. 8, the bearing housing 104 of the crankshaft 103 is a rotatable eccentric body, According to the crankshaft 103
The vertical position is corrected.

[0003] In a cam press machine as well, the position of the bottom dead center of the slide fluctuates due to the heat generated during operation. In particular, the viscosity of lubricating oil changes due to the rotational frictional heat of the bearing portion of the camshaft within a predetermined time after starting. The position of the bottom dead center of the slide is most likely to fluctuate due to elongation caused by the sliding frictional heat of the slide, and the fluctuation width may reach a maximum of about 0.2 mm. Therefore,
When performing severe press forming of a work that is out of the allowable dimension range due to such a change in the bottom dead center position,
After a predetermined time elapses after the start, the temperature rise reaches the saturation point, and the amount of change in the bottom dead center position of the slide decreases, and then the position of the mold in the reciprocating direction is adjusted. The current situation is that defective workpieces that have been press-formed during that time are discarded.

[0004]

The method corresponding to the change of the bottom dead center position in the cam press described in the prior art is based on a method in which the cam press is stopped after a lapse of a predetermined time from the start, and the direction of the reciprocation of the mold is changed. Since the position must be adjusted, there has been a problem that it is complicated and the production efficiency is low. In addition, since the defective work that has been press-formed is discarded between the start and the elapse of a predetermined time, material costs and time are wasted, and the manufacturing cost is increased. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the related art, and has as its object to automatically set the bottom dead center position of a slide with respect to a bolster to a desired position without stopping a cam press machine. It is an object of the present invention to provide a method and an apparatus for correcting a bottom dead center position of a cam press capable of performing stable press forming from the start.

[0005]

In order to achieve the above object, a method of correcting a bottom dead center position of a cam press according to the present invention comprises the steps of:
In a method of correcting a bottom dead center position of a slide with respect to a bolster which is changed by a thermal displacement of a cam press machine, a correction is performed by comparing a detected value of an actual bottom dead center position changed by a thermal displacement of the slide with a preset reference value. Find the value,
A pair of eccentric roller support shafts supporting a pair of cam rollers abutting on both sides of the rotating cam substantially on the vertical line are simultaneously rotated by an equal amount, and the axis of the journal portion of the roller support shaft is moved up or down by the correction value. To correct the position of the bottom dead center of the slide with respect to the bolster.

Further, in a bottom dead center position correcting device for a cam press machine having a pair of cam rollers rotatably abutting on substantially vertical sides of a cam rotating on a vertically movable slide, the cam is rotatably provided on the slide. A pair of roller support shafts in which a portion where the cam roller is fitted are eccentric, driving means for simultaneously rotating the pair of roller support shafts by the same amount, and a sensor for detecting a bottom dead center position of the slide;
The driving means is controlled such that the actual bottom dead center position detected by the sensor is compared with a preset reference bottom dead center position so that the actual bottom dead center position approaches the reference bottom dead center position. And a correction control means. Further, a bearing bush whose inner peripheral portion and outer peripheral portion are eccentric, which support one of the journal portions of the pair of eccentric roller support shafts,
A clamp member for loosening and tightening the bearing bush to the slide is added to make the distance between the axes of the pair of cam rollers variable.

[0007]

According to the first and second aspects of the present invention, the same value as the sensor output value when the slide is at the desired bottom dead center position is previously set and stored as a reference value. Detects the dead center position at each stroke, compares it with the reference value to determine a correction value, and rotates the pair of eccentric roller support shafts in phase with each other and simultaneously rotates the slide up or down. The position of the bottom dead center of the slide relative to the bolster is automatically corrected by displacing by the value. According to a third aspect of the present invention, the eccentric bearing bush interposed between one of the journal portions of the pair of roller support shafts and the corresponding hole of the slide is rotated, and the relationship between the axial centers of the pair of cam rollers with respect to the cam. Is adjusted, and after the adjustment is completed, the bearing bush is fixed to the slide by the clamp member to maintain the best distance between the shaft centers.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments will be described below with reference to the drawings. In the cam press machine shown in FIG. 1, a box-shaped frame 1 erected on the floor has a bolster 1a integrally at a position closer to the lower side, and a vertical guide 2 is provided inside the both side plates 1b, 1b.
2 are installed. A cam shaft 3 is rotatably and horizontally supported at a position closer to the upper side of the frame 1.
The central portion is rotatably supported on the lower surface of the upper plate portion 1c of the frame 1 by half-shaped bearings 4, 4 which are fixed. Two cams 5 and 5 having the same cam shape are fitted on the cam shaft 3 in the same phase at an interval from each other.
As shown in the enlarged view of FIG. 1, the cam shaft 3 is a cylindrical cam having the same dimension between the cam surfaces passing through the center of rotation, and the cam shaft 3 has a gear 8 meshed with a pinion of a flywheel shaft (not shown) by a motor 7 fixed on the upper plate 1c. Driven through.

A slide 9 is movably provided along the guides 2 and 2 of the frame 1, and a pair of cam rollers 11A and 1 abut on the slide 9 on substantially vertical sides of the cams 5 and 5 respectively.
1B and 11A, 11B are rotatably supported.
Each of the cam rollers 11A and 11B is a roller fitting portion 2r.
Are mounted via roller bearings on roller support shafts 12A, 12B which are eccentric to the journal portions 12j, 12j at both ends by a predetermined amount. The roller support shafts 12A, 12B are pivotally supported on the slide 9 via bearing bushes. ing.

The roller fitting portions 12 of the roller support shafts 12A, 12B with the journal portions 12j, 12j shown in FIG.
The eccentricity [alpha] of the upper and lower roller support shafts 12A, 12r is preferably in the range of 0.3 to 0.7 mm, preferably about 0.5 mm.
The 12A and the lower roller support shafts 12B, 12B are connected to each other at one end of a journal portion 12j coaxially by connecting shafts 13, 13, and worm wheels 14A, 14B are fitted to the center of each connecting shaft 13, respectively. ing. A correction motor 15 for NC driving is fixed on the upper plate portion 1c of the frame 1, and a bevel gear 16 fitted to the output shaft of the motor 15 has two worms 17a and 17b that mesh with the worm wheels 14A and 14B. The vertical drive shaft 18 having the spline 18a is meshed with a bevel gear 19 which is fitted to be vertically movable.

A pair of upper and lower roller support shafts 12A, 12B
3, only when the maximum eccentricity point a of the axis of the roller fitting portion 12r with respect to the axis of the journal portion 12j is on a horizontal line passing through the axis of the journal portion 12j as shown in FIG.
It is preferable that the maximum eccentric point a is vertically rotated about the horizontal line passing through the axis of the journal 12j by an equal amount. When the vertical drive shaft 18 is rotated, the upper worm 17a and the worm wheel 14A and the lower worm 17b and the worm wheel 14B rotate the worm wheels 14A and 14B in opposite directions and at the same rotation angle. It is a combination that you do.

The rotation angle θt of the journal portions 12j, 12j of the roller support shafts 12A, 12B shown in FIG. 4 is, for example, when α = 0.5 mm, the roller support shafts 12A, 12B.
Rotation angle θt of journal portions 12j, 12j of B = 30
In degrees, the downward displacement amount δ of the journal portions 12j, 12j
t can be secured approximately 0.25 mm, and the upward displacement amount δt can be secured approximately 0.25 mm by the rotation angle θr in the opposite direction shown in FIG. 5, so that θt + θr = 60 °
By rotating the slide 9 by approximately 30 ° within the range, the change in the bottom dead center of the slide 9 can be dealt with without any trouble.
3 to 5 are diagrams in which the amount of eccentricity α is exaggeratedly displayed. Further, an eccentric bearing bush 21 is rotatably interposed between the upper support shaft 12A and the corresponding hole 9a of the slide 9, and the bearing bush 21 can be fixed to a desired phase by a clamp bolt 22, and a cam is provided. 5, it is possible to cope with manufacturing errors or aging.

A sensor 24 is fixed upward on the bolster 1a via a mounting member 23, and a dog 25 is mounted on the slide 9 at a position facing the sensor 24.
As the sensor 24, for example, a displacement sensor such as an eddy current type proximity sensor can be used. When the slide 25 moves up and down and the dog 25 serving as a detection conductor approaches, a signal corresponding to the approach amount is output. The sensor can be used as long as it can output a signal corresponding to the amount of linear movement, such as a magnescale or a linear scale.

The block diagram in FIG. 2 shows that the correction motor 15 is controlled based on the sensor output to control the roller support shaft 1.
A correction control system 26 for displacing the axial positions of the journal portions 12j, 12j of the 2A, 12B upward or downward.
The maximum approach value storage unit 27 stores the maximum approach value of the sensor 24 when the slide 9 approaches the bolster 1a most. The comparison unit 28 compares a reference value stored in advance in the reference set value storage unit 29 with the maximum approach value. The correction amount calculation unit 30 calculates a correction amount by calculation. The motor drive unit 31 has a roller support shaft 12A corresponding to the correction amount,
The axial center amount δr of the journal portions 12j, 12j of the 12B,
This is a portion for supplying drive power to the correction motor 15 so as to obtain δt.

Next, the operation of this embodiment will be described. First, the same value as the output signal value of the sensor 24 when the bottom dead center position of the slide 9 is at the desired position is input and stored in the reference setting storage unit 29 as a reference setting value, and the operation of the cam press machine is started. Then, initially, the output signal of the sensor 24 and the storage unit 2
Since the reference set value of No. 9 is the same value, a signal of zero correction amount is output from the arithmetic unit 30 and no power is output from the motor drive unit 31, and press forming of a high precision work can be smoothly performed without correction. .

However, when the temperature of the components of the cam press machine gradually increases due to the operation and the bottom dead center position of the slide 9 lowers, the sensor 24 detects this at a resolution of, for example, 0.01 mm, and sets the reference set value. (Correction amount), and the driving unit 31 supplies electric power corresponding to the correction amount to rotate the correction motor 15. The rotation of the correction motor 15 is transmitted to the vertical drive shaft 18 by bevel gears 16 and 19, and the worms 17a and 17b
5, the journal 12j of the upper roller support shaft 12A in FIG. 5 is rotated counterclockwise and the journal 1 of the lower roller support shaft 12B via the connecting shaft 13.
2j is rotated clockwise and the roller support shafts 12A, 12A
The axis positions of the journal portions 12j, 12j of B are moved upward by an amount corresponding to the correction amount.

As a result, the position of the bottom dead center of the slide 9 for pivotally supporting the roller support shafts 12A and 12B is raised, and the sensor 24
Is equal to the reference value, and the desired bottom dead center position is maintained. If the bottom dead center position of the slide 9 changes upward for some reason, in FIG. 4, the journal portion 12j of the upper roller support shaft 12A is rotated clockwise and the journal of the lower roller support shaft 12B is rotated. Part 12
j is rotated counterclockwise to return to the desired bottom dead center position.

Next, a bolster 1a shown in FIGS.
The mechanical operation of correcting the bottom dead center position of the slide 9 for the slide 9 will be described in more detail. Roller support shafts 12A, 12B
As shown in FIG. 3, the slides 9 slide at a position where the pivot axes of the journal portions 12j and 12j oppose each other on the vertical line of the cam shaft 3.
And the upper and lower sides are rotated in opposite directions by the rotation of the vertical drive shaft 18 so that the roller fitting portions 12r, 1
The axis of 2r is the radius of the amount of eccentricity α and the journals 12j, 1
2j, the cam rollers 11A and 11B abut on the cam 5 at positions opposed to each other with the axis of the camshaft 3 interposed therebetween, thereby displacing the relative position. The position of the slide 9 is displaced with respect to the axis of the camshaft 3 together with 12j, and the position of the bottom dead center of the slide 9 with respect to the bolster 1a is corrected in accordance with the corrected rotation amount of the vertical drive shaft 18.

For example, when correcting the slide 9 in the state shown in FIG. 3 downward with respect to the bottom dead center position, the upper journal 12j of the roller support shafts 12A and 12B is clockwise and the lower journal 12j is When they are simultaneously rotated counterclockwise by θt degrees, the maximum eccentric point a becomes as shown in FIG.
Since it is displaced to the position of the intersection of the circumference of the eccentricity α and θt,
The relative position of the axis of the roller fitting portions 12r, 12r is displaced to this maximum eccentric point a, and the distance between the axes of the roller fitting portions 12r, 12r (that is, the rotation axes of the cam rollers 11A, 11B) is changed. While maintaining the distance P, the cam rollers 11A and 11B are respectively δ with respect to the axis of the journals 12j and 12j.
The journal part 12 rotates around the positions of t and αt as axes.
Since the axes of j and 12j are respectively displaced downward by δt, the slide 9 is corrected downward by δt. Then
When correcting the slide 9 in the state shown in FIG. 3 upward with respect to the bottom dead center position, the journals 12j and 12j are rotated by θr degrees as shown in FIG. By the same action as above, the slide 9 is moved upward by δ.
Correct by r.

Further, since the journal portion 12j of the upper roller support shaft 12A is supported by the slide 9 via the eccentric bearing bush 21, the eccentric bearing bush 2A is supported.
1 by changing the phase of the cam rollers 11A and 11B.
Can be adjusted, and a pair of cams 5,
In the case where there is some manufacturing error in the dimension between the cam surfaces passing through the rotation axis of the pair 5, or due to wear due to aging, the cam 5
When a gap equal to or more than a predetermined gap is formed between the cam rollers 11A and 11B, the clamp bolt 22 is loosened and the eccentric bearing bush 21 is rotated to adjust the best condition. After the adjustment, the clamp bolt 22 is tightened. The best condition can be maintained by fixing the bearing bush 21 to the slide 9.

[0021]

Since the present invention is configured as described above, the following effects can be obtained. A roller support shaft that supports a pair of cam rollers abutting on a cam of a cam press machine can be moved up and down, and the correction amount obtained from the actual bottom dead center position of the slide and a desired reference bottom dead center position stored in advance can also be determined. The bottom dead center position of the slide can be automatically corrected without stopping the cam press machine, so that high-quality work can be stably press-formed. As a result, the processing efficiency is improved and the defective rate is reduced. In addition, since one of the pair of cam rollers can be displaced up and down, it is possible to easily cope with errors in the manufacture of the cam or wear due to aging, etc., and always maintain the best relationship between the cam and the cam roller. Can be.

[Brief description of the drawings]

FIG. 1 is a front view of a cam press in which a cam and a cam roller according to an embodiment of the present invention are shown in cross section.

FIG. 2 is a side sectional view of FIG. 1 including a block diagram of a correction control system.

FIG. 3 is an enlarged view of a cam and a cam roller in which an eccentric amount of a support shaft is exaggeratedly displayed.

FIG. 4 is an enlarged view of a case where correction is performed downward with respect to a reference position in FIG. 3;

FIG. 5 is an enlarged view of a case where correction is performed upward with respect to the reference position of FIG. 3;

FIG. 6 is a diagram showing a displacement structure of an upper cam roller for making the distance between the axes of a pair of cam rollers variable.

FIG. 7 is a diagram of a bottom dead center position adjusting device of a conventional knuckle press.

FIG. 8 is a diagram of a bottom dead center position adjusting device of a prior art crank press.

[Explanation of symbols]

1 frame 3 cam shaft 5 cam 9 slide 11A, 11B cam roller 12A, 12B eccentric roller support shaft 13 connecting shaft 14A, 14B worm wheel 15 correction motor 17a, 17b worm 16, 19 bevel gear 18 vertical drive shaft 21 eccentric bearing bush 22 Clamp bolt 24 Sensor 26 Correction control system

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-53-144079 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B30B 15/06 B30B 1/26

Claims (3)

(57) [Claims] 1. A method of correcting a bottom dead center position of a slide with respect to a bolster which is changed by a thermal displacement of a cam press machine, wherein a detected value of an actual bottom dead center position which is changed by a thermal displacement of the slide and a preset reference value are determined. , And a pair of cam rollers abutting on almost both sides of the rotating cam on a vertical line are simultaneously rotated by the same amount by a pair of eccentric roller support shafts, and the journal portion of the roller support shaft is rotated. A method of correcting a bottom dead center position of a cam press, wherein the bottom center position of the slide relative to the bolster is corrected by moving an axis center upward or downward by the correction value. 2. A bottom dead center position correcting device for a cam press machine having a pair of cam rollers rotatably abutting on substantially vertical sides of a cam rotating on a slide movable up and down, wherein the slide is rotatably provided on the slide. A pair of roller support shafts in which a portion where the cam roller is fitted is eccentric, and a driving means for simultaneously rotating the pair of roller support shafts by the same amount,
A sensor for detecting the bottom dead center position of the slide, and comparing the actual bottom dead center position detected by the sensor with a preset reference bottom dead center position, A bottom dead center position correcting device for a cam press, comprising: a correction control unit that controls the driving unit so that the dead center position approaches. 3. A bearing bush whose inner peripheral portion and outer peripheral portion are eccentric to support one journal of a pair of eccentric roller support shafts, and a clamp member for loosening and tightening the bearing bush to a slide. The bottom dead center position correcting device according to claim 2, wherein the distance between the axes of the pair of cam rollers is made variable by adding the following.