JP2013066895A - Device for detecting bottom dead center of slide of press - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for detecting the bottom dead center which has little change in the position of a sensor, is manufactured easily and excellent in cost performance.SOLUTION: The device 14 for detecting the bottom dead center of the slide of the press includes: detecting sensors 15a; sensors 15b to be detected; and fixing members 16 for fixing at least one of the detecting sensor or a sensor to be detected to a slide 12 or a bolster 5. The fixing member is provided with a first member 17 and a second member 19 which is connected with one end of the first member and extends in parallel with and in the same direction as the first member. By making the length of the first member longer than the length of the second member and making the linear expansion factor of the first member smaller than the linear expansion factor of the second member, the respective change in the length of the first member and the second member caused by thermal expansion are made nearly equal to each other.

Description

  The present invention relates to a slide bottom dead center detection device for a press machine. More specifically, the present invention relates to a slide bottom dead center detection device that detects a change in the bottom dead center position of a slide.

  Due to the sliding heat generated by the operation of the press machine, the member that drives the slide and the member that suspends the member are thermally expanded. As a result, the lengths of these parts are extended and the bottom dead center of the slide is changed (hereinafter referred to as thermal displacement). In addition, the inertial force applied to the slide and the upper die changes as the operating speed of the press machine increases and decreases. As a result, a member that suspends the slide or the like is elastically deformed and changes the bottom dead center of the slide (hereinafter referred to as spm displacement). For this reason, the press machine is provided with a bottom dead center correction device for correcting the bottom dead center of the slide. The apparatus calculates a deviation between a detection value obtained from a sensor for detecting the bottom dead center of the slide and a set value by the control apparatus, and adjusts the height position of the slide so that the deviation is zero.

  In addition, the member having the position detection sensor attached to the press machine also thermally expands due to the influence of heat generated by the press machine and the mold and the surrounding temperature change. For this reason, some of the mounting members use a low thermal expansion material such as Ni-resist or Novinite (registered trademark). Further, there is a material using a super invar material whose thermal expansion is almost zero.

  Patent Document 1 discloses a die height correction device that takes into account the influence of the ambient temperature of the slide position detection means and its mounting member in the correction of the die height. This die height correcting device includes a driving device for adjusting die height, an NC device for instructing a driving amount command value to the driving device, slide position detecting means for detecting die height position information to be sent to the NC device, and And an auxiliary frame for attaching to the press machine. The lower end of the auxiliary frame is pivotally attached to the side of the frame of the main body of the press machine, and the auxiliary frame is held in an upright state by a fall-preventing means. The upper end of the auxiliary frame is a free end where the expansion and contraction is not restricted, and the sensor head of the slide position detecting means is provided there. On the other hand, the slide is provided with a sensor rod of a slide position detecting means, and the position of the sensor rod at the slide bottom dead center is detected by the sensor head. Based on the detected value, a command value that the NC device commands the drive device is calculated. The auxiliary frame and the sensor head are provided with temperature detecting means, respectively. These temperature signals are taken into the NC device, where the amount of expansion / contraction of the auxiliary frame and the amount of temperature drift of the slide position detecting means are calculated, and the calculated values are added to or subtracted from the command value. Thereby, the command value is corrected, and the corrected command value is commanded to the drive device.

  Patent Document 2 discloses a technique for covering a slide position detecting means and a mounting member provided with the position detecting means with a heat insulating sheet or forming these members with a heat insulating member. These heat insulating sheets reduce the temperature change of the position detecting means and its mounting member, and the length change due to thermal expansion is reduced.

Japanese Patent Laid-Open No. 10-15699 JP 2005-319489 A

In Patent Document 1, the control is complicated because the die height is corrected in consideration of the temperature change. Even if the position detecting means or the like is covered with a heat insulating sheet as in Patent Document 2 or a low thermal expansion material is used for the position detecting means or the like, the thermal expansion cannot be made substantially zero. When a super invar material of a low thermal expansion material is used, the coefficient of thermal expansion can be reduced to almost zero, but this is a difficult-to-process material containing a large amount of Ni as a component, and further expensive because it contains Co as a component.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a slide bottom dead center detection device that is less likely to change in sensor position, easy to manufacture, and excellent in cost performance.

A slide bottom dead center detection device according to the present invention (Claim 1) includes at least one of a detection sensor attached to one of a slide and a bolster, a detection sensor attached to the other, and the detection sensor or detection sensor. An attachment member attached to the slide or bolster at a predetermined height, the attachment member being connected to a first member disposed in the vertical direction, and one end connected to one end of the first member; A second member extending in parallel toward the other end, one end of the first member or the second member being attached to a slide or a bolster, and the other or the other end having the detection sensor or the detected sensor. Attached, the length of the first member is made longer than the length of the second member, the linear expansion coefficient of the first member is made smaller than the linear expansion coefficient of the second member, 1 the length of the member L1, the length of the second member L2, the linear expansion coefficient α2 of the linear expansion coefficient α1 and the second member of the first member, which satisfies the equation 1, is characterized in that.
| α1L1-α2L2 | <α1 (L1-L2) (Formula 1)

  In such a slide bottom dead center detection device, it is preferable that the first member and the second member have substantially the same length change due to thermal expansion (Claim 2). It is preferable that the first member and the second member have substantially the same heat capacity. It is preferable that a heat insulating member is provided between the mounting member and the slide or bolster. Further, it is preferable that one of the detection sensor and the detected sensor is attached to an attachment member and the other is attached to the slide or bolster via a heat insulating material. Further, it is preferable that the first member is two columnar members, and the second member is disposed between the first members.

  In the slide bottom dead center detecting device of the present invention (Claim 1), the first member and the second member are connected at the same end portion (connecting end). For this reason, when one member is thermally expanded or contracted due to a temperature change in the press machine or its surroundings, the other member is thermally expanded or contracted in the opposite direction. If the difference in length change due to thermal expansion or contraction between these two members (the first member and the second member) is within a range satisfying Equation 1, it is a detection sensor compared to using only a member having a small linear expansion coefficient. Alternatively, the relative position change of the detected sensor with respect to the slide or bolster can be reduced. For this reason, when a detection sensor or a detected sensor is attached to the other end of one member and the other end of the other member is fixed to the slide or bolster, the detection sensor or the detected sensor moves relative to the slide or bolster. Can be reduced. For this reason, even if the temperature changes, the accurate bottom dead center of the slide can be detected, and the height of the slide can be adjusted based on the detected value, so that the accuracy of press working is improved.

  The first member is longer than the second member, and the linear expansion coefficient of the second member is larger than that of the first member. Therefore, the difference between the length of the first member and the length of the second member can be used as the height at which the detection sensor is disposed.

In such a slide bottom dead center detection device, when the length changes due to the thermal expansion of the first member and the second member are substantially the same (claim 2), both members (the first member and the first member) The length change due to thermal expansion or contraction of each of the two members is prevented, and there is no relative position change between the other ends of the two members. For this reason, the accurate bottom dead center of the slide can be detected, and the height of the slide can be adjusted based on the detected value, thereby improving the accuracy of press working.

  Further, when the heat capacities of the first member and the second member are substantially the same (Claim 3), the rate of length change due to thermal expansion and contraction can be made substantially the same, so that more accurate The bottom dead center of the slide can be detected.

  Further, when a heat insulating member is provided between the mounting member and the slide or bolster (Claim 4), heat transfer to the mounting member is suppressed and thermal expansion and contraction are prevented. The bottom dead center of the slide can be detected. When one of the detection sensor and the detected sensor is attached to an attachment member and the other is attached to the slide or bolster via a heat insulating material (Claim 5), the sensor itself is heated. Since it is not easily affected, the bottom dead center of the slide can be detected more accurately. Furthermore, when the first member is two columnar members and the second member is disposed between the first members (Claim 6), the support of the second member is stable.

FIG. 1 is a schematic view showing an embodiment of a press machine using the slide bottom dead center detecting device of the present invention. FIG. 2 is an enlarged view of the slide bottom dead center detecting device shown in FIG. FIG. 3 is a side view of FIG. 4a, 4b, and 4c are enlarged views showing other embodiments of the slide bottom dead center detecting device, respectively. FIGS. 5 a, 5 b, 5 c, and 5 d are enlarged views showing embodiments of the slide bottom dead center detection device in which the attachment member is attached to the slide. 6a and 6b are enlarged views showing embodiments in which the attachment members are attached to the slide and the bolster, respectively.

  First, a press machine equipped with a slide bottom dead center detection device (hereinafter referred to as a bottom dead center detection device) of the present invention will be described with reference to FIG. A press machine 1 shown in FIG. 1 includes a frame that includes a bed 2, columns 3 that rise from four front, rear, left, and right sides of the bed, and a crown 4 that is provided at the upper end of the columns. A bolster 5 is disposed above the bed 2.

  As shown in FIG. 1, a press driving motor 6 is arranged on the upper surface of the crown 4. A pulley 6 a is attached to the drive shaft of the motor 6. A bearing (not shown) is provided on the side surface of the crown 4, and both ends of the crankshaft 7 are rotatably supported by the bearing. A flywheel 8 is attached to one end (right end portion in the figure) of the crankshaft 7, and a belt 9 is hung between the flywheel 8 and the pulley 6a. The belt 9 transmits the rotational force from the motor 6 to the flywheel 8. Further, the flywheel 8 has a clutch / brake 8a therein, which turns on and off the rotational drive of the crankshaft 7.

  Near the center of the crankshaft 7, two eccentric portions 7a, 7a are provided in series. Connecting rods 10 and 10 are connected to the eccentric parts 7a and 7a, respectively. A suspension 11 is connected to the small ends of the connecting rods 10 and 10 via a ball joint 10a. A slide 12 is attached to the lower end of the suspension 11.

  The suspension 11 adjusts the position of the bottom dead center of the slide 12 with respect to the bolster 5 by expanding and contracting its length. Each of the suspensions 11 and 11 includes a bolt-nut mechanism (not shown) that converts the rotational motion of the male screw member 13 into a telescopic motion. A slide adjusting servo motor 13a is provided at an end portion (right end in the figure) of the male screw member 13, and the male screw member 13 is driven to rotate. The rotational movement rotates the bolt member of the bolt-nut mechanism. The bolt member is provided near the lower end of the connecting rod 10. On the other hand, the nut member is provided on the slide 12 side so as not to rotate. For this reason, when the bolt member is rotated, the nut member moves relative to the bolt member. Thereby, the height of the slide 12 is adjusted. The male screw member 13 and the slide adjusting servo motor 13 a are fixed to the lower surface of the crown 4. By the expansion and contraction of the suspension 11, the displacement of the slide based on the spm displacement and the thermal displacement is corrected.

  The rotational force of the press drive motor 6 is transmitted to the flywheel 8 via the belt 9 to rotate the crankshaft 7. Thereby, the eccentric part 7a rotates around the axis of the crankshaft 7. The large end portion of the connecting rod 10 moves up and down while sliding with the peripheral surface of the eccentric portion 7a. On the other hand, the small end portion of the connecting rod 10 is guided by a plunger guide (not shown) provided on the lower surface of the crown 4 and moves up and down. Accordingly, the slide 12 is guided by a slide give (not shown) provided in the column 3 and moves up and down.

The bolster 5 and the slide 12 are provided with a bottom dead center detecting device 14 for detecting a bottom dead center of the slide 12. In FIG. 1, the bottom dead center detectors 14 are provided on both sides of the bolster 5, and the detection values obtained from the left and right bottom dead center detectors 14 and 14 are averaged to calculate the bottom dead center of the center of the slide 12. ing. As a result, even when a load does not act evenly on the slide 12 and the slide 12 is tilted left and right or front and rear, the bottom dead center of the center portion of the slide 12 can be accurately detected. The bottom dead center detection device 14 may be provided only at one location in the center of the slide 12.
As shown in FIG. 2, the bottom dead center detection device 14 includes a detection sensor 15 a attached to the bolster 5, a detected sensor 15 b attached to the slide 12, and the detection sensor 15 a at a predetermined height with respect to the bolster 5. And an attachment member 16 to be fixed. The attachment member 16 has a lower end attached to the upper surface of the bolster 5, a first member 17 extending upward, a connecting member (upper stay) 18 connected to the upper end of the first member, and an upper end connected to the upper stay 18. The second member 19 is provided in parallel with the first member 17 and extending downward. The detection sensor 15 a is attached to the free end (the lower end in the figure) of the second member 19. The first member 17 is longer than the second member 19, and the detection sensor 15 a is held at a position higher than the upper surface of the bolster 5 by the difference.

  Note that the first member 17 and the second member 19 may be directly connected without using the upper stay 18. For example, a step portion is formed on the upper portion of both the first member 17 and the second member 19 or on the upper portion of either member, and both the members are fastened with bolts or the like at the step portion. The free end is prevented from contacting the first member 17. Further, a concave portion may be provided on one of the first member 17 and the second member 19, and a convex portion may be provided on the other, and they may be combined and connected. Further, a connecting piece may be provided in one of the first member 17 and the second member 19, and a fitting hole for fitting the connecting piece may be formed in the other, and the two members may be connected by fitting them.

The detection sensor 15a for detecting the bottom dead center of the slide 12 is attached to a member (bolster 5) serving as a reference for detection, and is a sensor head in this embodiment. On the other hand, the detected sensor 15b is attached to the detected side (slide 12), which is a sensor rod in this embodiment. The sensor head 15a is a magnetic head for detecting magnetic force. Examples of the sensor rod and sensor head include a Magnescale (registered trademark) that detects the position of the sensor rod by detecting a magnetic pattern of a predetermined period provided on the sensor rod. When the position of the lower surface of the slide 12 is directly detected by the detection sensor 15a that detects the height of the slide 12, the lower surface itself becomes the detected sensor 15b. In addition to the Magnescale (registered trademark), an ultrasonic wave, a laser or a capacitor using a capacitance, or a contact type sensor may be used.

  The present invention is characterized by a combination of linear expansion coefficients and lengths of the first member 17 and the second member 19. That is, assuming that the linear expansion coefficient (1 / ° C.) is α and the member length is L (see FIG. 3), the length change due to thermal expansion of each member 17 and 19 is αL. Here, the linear expansion coefficient α1 of the first member 17 is smaller than the linear expansion coefficient α2 of the second member 19 (α1 <α2). The subscripts 1 and 2 indicate the first member and the second member, respectively. The length L1 of the first member 17 is longer than the length L2 of the second member 19 (L1> L2). In addition, the first member 17 and the second member 19 have substantially the same length change due to thermal expansion (α1L1 = α2L2). Therefore, when the temperature of the first member 17 increases by t ° C. and extends by tα1L1, even if the upper stay 18 moves upward by that amount, the second member 19 also increases by t ° C. and extends by tα2L2. Therefore, the elongation of both is offset, and the height of the detection sensor 15a relative to the upper surface of the bolster 5 does not change. Thereby, the bottom dead center position of the slide 12 can be accurately detected.

  If the first member 17 and the second member 19 have the same length change due to thermal expansion, there is no relative position change between the other ends of the members 17 and 19. For this reason, it is possible to prevent the detection sensor 15a from moving relative to the bolster 5. For this reason, even if the temperature changes, the accurate bottom dead center of the slide 12 can be detected, and the height of the slide 12 can be adjusted based on the detected value, so that the accuracy of press working is improved.

Even if the length changes due to thermal expansion or contraction of the two members 17 and 19 are not the same, the difference in length change due to thermal expansion or contraction of the both members 17 and 19 is within the range satisfying Equation 1. If so, the relative movement of the detection sensor 15a with respect to the bolster 5 can be reduced compared to using only a member having a small linear expansion coefficient α1. Thereby, the accurate bottom dead center of the slide 12 can be detected, the height of the slide 12 can be adjusted based on the detected value, and the accuracy of press working can be improved.
For example, when the mounting member 16 including the first member 17 and the second member 18 is regarded as one member, the apparent linear expansion coefficient αa of the mounting member 16 is | (α1L1−α2L2) / (
L1-L2) |. Each parameter is set so that the apparent linear expansion coefficient αa is further smaller than the smaller linear expansion coefficient α1, that is, | (α1L1-α2L2) / (L1-L2) | <α1 is satisfied. To do. As a result, the above-described equation 1 is derived.

  The first member 17 and the second member 19 preferably have substantially the same heat capacity (J / ° C.). If the amount of heat per hour received by each of the first member 17 and the second member 19 is substantially the same, both masses are adjusted so that the heat capacities of the first member 17 and the second member 19 are substantially the same. This is because the degree of temperature change of the members can be made substantially the same, and the speed of the length change due to the thermal expansion of the members can be made almost the same. Thereby, more accurate bottom dead center detection of the slide 12 can be performed.

The material of the first member 17 is Ni-resist, Novinite (registered trademark), etc., and Ni-resist is preferably used. The linear expansion coefficient (1 / ° C.) is 2 × 10 ^{−6 to} 7 × 10 ⁻⁶ . The first member 17 is a prismatic member having a square cross section. In addition, you may make the 1st member 17 into a plate-shaped member, or you may make it into the rod shape which made the cross section circular shape or rectangular shape.

The material of the second member 19 is stainless steel, iron or aluminum alloy. Their linear expansion coefficients (1 / ° C.) are 11 × 10 ⁻⁶ (iron) to 22 × 10 ⁻⁶ (aluminum alloy). The second member 19 has a plate shape. Since it is plate-shaped, it is easy to increase the heat capacity by increasing the dimension in the direction (lateral direction) perpendicular to the length L2 while keeping the length L2. The shape may be the same as that of the first member 17.

  The ratio of the length L2 of the second member 19 to the length L1 of the first member 17 is preferably set to about 0.2 to 0.3 by specifying the type of the member.

  As shown in FIG. 3, the number of the first members 17 is two, and a plate-like second member 19 is disposed between them. The upper ends of the first members 17 and 17 and the second member 19 are connected by an upper stay 18 (connection end). On the other hand, lower ends of the first members 17 and 17 are connected to each other by a lower stay 20, and the lower stay 20 is fixed to the bolster 5. A sensor head mounting member 21 is provided at the lower end (free end) of the second member 19, and the sensor head 15a is mounted thereon. The sensor head mounting member 21 is a plate-like member, and one end thereof is connected to the lower end of the second member 19. The other end side extends inward, and a through hole (not shown) through which the sensor rod 15b passes or a U-shaped notch is formed in the inwardly extending portion. A sensor rod attachment member 22 is attached to the side surface of the slide 12, and a sensor rod 15 b is attached to the sensor rod attachment member 22.

  The sensor head 15a may be attached to the slide 12, and the sensor rod 15b may be attached to the bolster 5 via the attachment member 16 (see FIG. 4a). At that time, the sensor head 15 a is fixed to the slide 12 through the sensor head mounting member 21, and the sensor rod 15 b is fixed to the mounting member 16 through the sensor rod mounting member 22.

  The upper stay 18 and the lower stay 20 connect the upper ends and the lower ends of the two first members 17 and 17, respectively. Therefore, the two first members 17 and 17 can be stably fixed to the bolster 5. The upper stay 18 is made of steel such as stainless steel, iron or aluminum alloy.

  A side surface on the long side of the second member 19 is disposed so as not to contact the adjacent first members 17 and 17. That is, since the members 17 and 19 have different linear expansion coefficients, a gap is formed so as not to prevent thermal expansion from each other.

  In the present embodiment, there are two first members 17, but one may be provided, or three or more may be provided. In the case of three or more, both ends may be connected by the above-described stays 18 and 20 as in the case of two.

  Furthermore, it is preferable to provide a heat insulating material 23 between the first member 17 and the bolster 5. Thereby, the thermal expansion of the 1st member 17 can be made small. Further, it is preferable to provide a heat insulating material 23 between the sensor rod mounting member 22 and the slide 12. As a result, the sensor rod 15b is not easily affected by heat, so that more accurate bottom dead center detection can be performed.

  The height detection value of the slide 12 detected by the sensor head 15a is transmitted to the control device 24. The control device 24 calculates the expansion / contraction amount of the suspension 11 based on the detected value, calculates the drive amount of the slide adjustment servo motor 13a that achieves the expansion / contraction amount, and uses the calculated drive amount as the slide adjustment servo. Commands the motor 13a. Here, since the mounting member 16 prevents a change in the position of the sensor head 15a due to heat, it is necessary to adjust the change in the thermal expansion of the mounting member 16 to the detected value transmitted from the sensor head 15a on the control device 24 side. There is no.

2, the first member 17 is fixed to the upper surface of the bolster 5, and the second member 1
A sensor head 15 a is provided at the lower end of 9. However, as shown in FIG. 4b, the second member 19 is fixed to the bolster 5 via the second member bracket 26 and extended downward, the lower end of the first member 17 is connected to the lower end, and the first member 17 is extended upward. A sensor head 15 a may be attached to the upper end of the member 17. Further, as shown in FIG. 4 c, the sensor head 15 a of the embodiment in FIG. 4 b may be attached to the slide 12 and the sensor rod 15 b may be attached to the first member 17. The second member bracket 26 is an L-shaped bracket formed by bending a plate-like member, and one plate is fixed to the upper surface of the bolster 5 via a heat insulating material 23. The other plate fixes the second member 19. The second member bracket 26 may be used to fix the second member 19 to the slide 12 as will be described later.

  In the above embodiment, the attachment member 16 is attached to a member serving as a reference for detecting bottom dead center such as the bolster 5, but the attachment member 16 may be attached to the slide 12 as shown in FIGS. In the bottom dead center correcting device 14 shown in FIG. 5 a, the first member 17 is attached to the slide 12. The sensor head 15 a is attached to the second member 19, and the sensor rod 15 b is attached to the bolster 5. The first member bracket 25 is an L-shaped bracket formed by bending a plate-like member. The first member bracket 25 may be used to fix the first member 17 to the bolster 5 as described later. Further, as shown in FIG. 5b, the mounting positions of the sensor head 15a and the sensor rod 15b in FIG. 5a may be interchanged. Further, as shown in FIG. 5c, the second member 19 may be fixed to the slide 12, extended upward, the upper end of the first member 17 connected to the upper end, and the sensor head 15a attached to the lower end. Further, as shown in FIG. 5d, the mounting positions of the sensor head 15a and the sensor rod 15b in FIG. 5c may be interchanged.

  As shown in FIGS. 6a and 6b, the sensor head 15a and the sensor rod 15b may be attached to the bolster 5 and the slide 12 via the attachment member 16, respectively. In FIG. 6 a, each attachment member 16 has a first member 17 attached to the slide 12 and the bolster 5, and a sensor head 15 a and a sensor rod 15 b attached to the second member 19. Further, as shown in FIG. 6b, the second member 19 may be attached to the bolster 5 and the slider 12 via the second member bracket 26, respectively. 6a and 6b, the mounting positions of the sensor head 15a and the sensor rod 15b may be interchanged. 6a may be combined with the lower mounting member 16 in FIG. 6b, and conversely, the lower mounting member 16 in FIG. 6a may be combined with the upper mounting member 16 in FIG. 6b. .

DESCRIPTION OF SYMBOLS 1 Press machine 2 Bed 3 Column 4 Crown 5 Bolster 6 Motor 7 Crankshaft 7a Eccentric part 8 Flywheel 8a Clutch and brake 9 Belt 10 Connecting rod 10a Ball joint 11 Suspension 12 Slide 13 Male screw member 13a Slide adjustment servo motor 14 Slide bottom dead Point detector (bottom dead center detector)
15a Sensor head (detection sensor)
15b Sensor rod (detected sensor)
16 Mounting member 17 First member 18 Upper stay (connecting member)
19 Second member 20 Lower stay 21 Sensor head mounting member 22 Sensor rod mounting member 23 Heat insulating material 24 Control device 25 First member bracket 26 Second member bracket α1 Linear expansion coefficient α2 of the first member Linear expansion coefficient αa of the first member Apparent linear expansion coefficient L1 First member length L2 Second member length t Temperature

Claims (6)

A detection sensor attached to one of a slide or a bolster;
A detected sensor attached to the other;
An attachment member for attaching at least one of the detection sensor or the detected sensor to a slide or bolster at a predetermined height;
The mounting member includes a first member disposed in the vertical direction, and a second member having one end connected to one end of the first member and extending in parallel toward the other end of the first member,
One end of the first member or the second member is attached to a slide or bolster, and the other end is attached to the detection sensor or detected sensor.
The length of the first member is longer than the length of the second member,
Reducing the linear expansion coefficient of the first member compared to the linear expansion coefficient of the second member;
The slide bottom deadline inspection of the press machine in which the length L1 of the first member, the length L2 of the second member, the linear expansion coefficient α1 of the first member, and the linear expansion coefficient α2 of the second member satisfy Expression 1. Out device.
| α1L1-α2L2 | <α1 (L1-L2) (Formula 1)   The slide bottom dead center detection device for a press machine according to claim 1, wherein the length changes due to thermal expansion of each of the first member and the second member are substantially the same.   The slide bottom dead center detection device for a press machine according to claim 1 or 2, wherein the heat capacities of the first member and the second member are substantially the same.   4. The slide bottom dead center detection device for a press machine according to claim 1, wherein a heat insulating member is provided between the mounting member and the slide or bolster. One of the detection sensor or the detected sensor is attached to an attachment member,
The slide bottom dead center detection device for a press machine according to any one of claims 1 to 4, wherein the other is attached to the slide or the bolster via a heat insulating material.   The slide bottom dead center detection device for a press machine according to any one of claims 1 to 5, wherein the first member is two columnar members, and the second member is disposed between the first members.

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