Hydraulic circuit control device and molding machine

Abstract

This hydraulic circuit control device comprises: a drive motor; a drive-side cylinder including a drive-side fluid chamber, and a drive-side piston moved by the drive motor; a driven-side cylinder including a driven-side fluid chamber, a fluid path that connects the driven-side fluid chamber and the drive-side fluid chamber, and a driven-side piston which is moved according to an increase / decrease in the amount of a working fluid inside the driven-side fluid chamber through the fluid path which is caused by the movement of the drive-side piston; and a fluid path volume adjustment mechanism which increases / decreases the volume of the fluid path according to an increase / decrease in the volume of the working fluid.

Description

[Technical Field]

[0001] The present invention relates to a hydraulic circuit control device and a molding machine, and more particularly to a hydraulic circuit control device and a molding machine that include a drive cylinder and a driven cylinder driven by the drive cylinder. [Background technology]

[0002] BACKGROUND ART Conventionally, a hydraulic cylinder device including a drive cylinder and a driven cylinder driven by the drive cylinder has been known. Such a hydraulic cylinder device is disclosed, for example, in Japanese Patent Application Laid-Open No. 2000-356202.

[0003] The above-mentioned Japanese Patent Application Laid-Open No. 2000-356202 discloses a hydraulic cylinder device including a drive cylinder and a control cylinder (driven cylinder) driven by the drive cylinder. The oil chamber in the drive cylinder and the oil chamber in the control cylinder are connected via a hydraulic hose (fluid path). The hydraulic cylinder device is configured such that as the piston of the drive cylinder moves forward and backward, hydraulic oil from the oil chamber in the drive cylinder flows into the oil chamber in the control cylinder via the hydraulic hose, causing the piston of the control cylinder to move. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-356202 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the hydraulic cylinder device described in JP 2000-356202 A, the volume of the hydraulic oil may fluctuate due to temperature changes, leakage, etc. In this case, the amount of movement of the piston of the control cylinder (driven cylinder) relative to the predetermined amount of movement of the piston of the drive cylinder changes (deviation from the set value) before and after the volume of the hydraulic oil fluctuates, which poses a problem in that it is not possible to ensure the positional accuracy of the piston of the control cylinder (driven cylinder).

[0006] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide a hydraulic circuit control device and a molding machine that can ensure the positional accuracy of the driven piston of the driven cylinder even when the volume of the working fluid fluctuates due to temperature changes or leakage of the working fluid. [Means for solving the problem]

[0007] In order to achieve the above object, a hydraulic circuit control device according to a first aspect of the present invention comprises: a drive motor, a drive cylinder including a drive piston moved by the drive motor; a driven cylinder including a driven piston; a fluid passage connecting the driven piston and the drive piston; and a driven piston that is moved as the drive piston moves and the amount of hydraulic fluid in the driven piston increases or decreases through the fluid passage; and a fluid passage volume adjustment mechanism that increases or decreases the volume of the fluid passage in accordance with an increase or decrease in the volume of the hydraulic fluid. The fluid path includes a main fluid path portion through which hydraulic fluid flows between the driven-side fluid chamber and the driving-side fluid chamber, and an adjustment fluid path portion connected to the main fluid path portion. The fluid path volume adjustment mechanism includes a volume adjustment motor that moves the inner wall surface of the adjustment fluid path portion, and is configured to increase or decrease the volume of the adjustment fluid path portion by moving the inner wall surface. .

[0008] As described above, the hydraulic circuit control device according to a first aspect of the present invention includes a drive-side cylinder including a drive-side piston, a driven-side cylinder including a driven-side piston that moves as the drive-side piston moves and the amount of hydraulic fluid in the driven-side fluid chamber increases or decreases through the fluid passage, and a fluid passage volume adjustment mechanism that increases or decreases the volume of the fluid passage in response to an increase or decrease in the volume of the hydraulic fluid. This allows the fluid passage volume adjustment mechanism to increase or decrease the volume of the fluid passage in response to an increase or decrease in the volume of the hydraulic fluid, even if an increase or decrease in the volume of the hydraulic fluid occurs due to temperature changes or leakage of the hydraulic fluid in the fluid passage, the driven-side fluid chamber, and the drive-side fluid chamber. Therefore, by increasing or decreasing the volume of the fluid passage using the fluid passage volume adjustment mechanism, an increase or decrease in the volume of the hydraulic fluid can be absorbed so that the increase or decrease in the volume of the hydraulic fluid does not affect the amount of movement of the driven-side piston. In other words, the amount of movement of the driven-side piston can be corrected so that the amount of movement of the driven-side piston relative to a predetermined amount of movement of the drive-side piston is maintained approximately constant. As a result, even if the volume of the hydraulic fluid fluctuates due to temperature changes or leakage of the hydraulic fluid, the positional accuracy of the driven-side piston of the driven-side cylinder can be ensured. In addition, the volume of the adjustment liquid path section can be increased or decreased by moving the inner wall surface of the adjustment liquid path section using the volume adjustment motor, so the amount of movement of the driven side piston can be easily corrected and the positional accuracy of the driven side piston in the driven side cylinder can be easily ensured.

[0011] In the hydraulic circuit control device according to the first aspect, the fluid path volume adjustment mechanism preferably includes a movement adjustment detection unit that detects at least one of the positions of the driven side piston and the driving side piston and the state of the hydraulic fluid in order to adjust the amount of movement of the driven side piston relative to the movement of the driving side piston, and is configured to increase or decrease the volume of the fluid path based on the detection result of the movement adjustment detection unit.

[0012] With this configuration, the movement amount of the driven piston can be corrected based on the results of detection by the movement adjustment detection unit of at least one of the positions of the driven piston and the driving piston and the state of the hydraulic fluid, so that the positional accuracy of the driven piston in the driven cylinder can be more reliably ensured depending on the positions of the driven piston and the driving piston and the state of the hydraulic fluid.

[0013] In this case, the movement adjustment detection unit preferably includes at least one of a position detection unit that detects the positions of the driving side piston and the driven side piston, a liquid temperature detection unit that detects the temperature of the working liquid, and a liquid pressure detection unit that detects the pressure of the working liquid, and the liquid path volume adjustment mechanism is configured to increase or decrease the volume of the liquid path based on the detection results of at least one of the position detection unit, the liquid pressure detection unit, and the liquid temperature detection unit.

[0014] With this configuration, the positions of the driving piston and the driven piston, which indicate a change in the amount of movement of the driven piston (deviation from the set value), and the temperature and pressure of the working fluid, which affect the change in the amount of movement of the driven piston, can be detected, and the amount of movement of the driven piston can be appropriately corrected according to various conditions.

[0015] A hydraulic circuit control device according to a second aspect of the present invention comprises a drive motor, a drive cylinder including a drive fluid chamber and a drive piston moved by the drive motor, a driven cylinder including a driven fluid chamber, a fluid passage connecting the driven fluid chamber and the drive fluid chamber, and a driven piston that is moved as the drive piston moves and the amount of hydraulic fluid in the driven fluid chamber increases or decreases through the fluid passage, and a fluid passage volume adjustment mechanism that increases or decreases the volume of the fluid passage in accordance with an increase or decrease in the volume of the hydraulic fluid, The liquid path volume adjustment mechanism includes a volume adjustment piston provided in the liquid path, and a volume adjustment ball screw mechanism having a volume adjustment piston attached to the volume adjustment piston, which increases or decreases the volume of the liquid path by moving the volume adjustment piston together with the volume adjustment ball screw.

[0016] As described above, a hydraulic circuit control device according to a second aspect of the present invention includes a drive-side cylinder including a drive-side piston, a driven-side cylinder including a driven-side piston that moves as the drive-side piston moves and the amount of hydraulic fluid in the driven-side fluid chamber increases or decreases through the fluid passage, and a fluid passage volume adjustment mechanism that increases or decreases the volume of the fluid passage in response to an increase or decrease in the volume of the hydraulic fluid. This allows the fluid passage volume adjustment mechanism to increase or decrease the volume of the fluid passage in response to an increase or decrease in the volume of the hydraulic fluid, even if an increase or decrease in the volume of the hydraulic fluid occurs due to temperature changes or leakage of the hydraulic fluid in the fluid passage, the driven-side fluid chamber, and the drive-side fluid chamber. Therefore, by increasing or decreasing the volume of the fluid passage using the fluid passage volume adjustment mechanism, an increase or decrease in the volume of the hydraulic fluid can be absorbed so that the increase or decrease in the volume of the hydraulic fluid does not affect the amount of movement of the driven-side piston. In other words, the amount of movement of the driven-side piston can be corrected so that the amount of movement of the driven-side piston is maintained approximately constant relative to a predetermined amount of movement of the drive-side piston. As a result, even if the volume of the hydraulic fluid fluctuates due to temperature changes or leakage of the hydraulic fluid, the positional accuracy of the driven piston of the driven cylinder can be ensured. Since the volume adjustment piston can be moved by the volume adjustment ball screw mechanism, the volume adjustment piston can be moved with precision, and the volume of the adjustment liquid path portion can be adjusted with precision.

[0017] The hydraulic circuit control device according to the first aspect preferably further comprises a drive-side ball screw mechanism having a drive-side ball screw to which a drive-side piston is attached and driven by a drive motor to move the drive-side piston together with the drive-side ball screw, and a drive-side ball screw cooling passage provided inside the drive-side ball screw and through which a refrigerant flows to cool the drive-side ball screw.

[0018] With this configuration, the drive side ball screw to which the drive side piston is attached can be cooled by the drive side ball screw cooling path, thereby suppressing the temperature rise of the working fluid through the drive side ball screw and the drive side piston, and suppressing the volume change of the working fluid itself caused by the temperature rise of the working fluid.

[0019] In the hydraulic circuit control device according to the first aspect, the hydraulic path volume adjustment mechanism is preferably configured to increase or decrease the volume of the hydraulic path based on at least one of a state index value that directly indicates an increase or decrease in the volume of the hydraulic fluid and a state index value that indirectly indicates an increase or decrease in the volume of the hydraulic fluid.

[0020] This configuration allows the volume of hydraulic fluid to be increased or decreased more accurately by taking into account at least one of an index value that directly indicates an increase or decrease in the volume of hydraulic fluid and an index value that indirectly indicates an increase or decrease in the volume of hydraulic fluid, thereby improving the positional accuracy of the driven piston of the driven cylinder.

[0021] The first aspect of this invention 3 The molding machine in this aspect comprises a fixed section to which a fixed mold is attached, a movable section to which a movable mold is attached, and a hydraulic circuit control device provided on the movable section to move the movable section relative to the fixed section, wherein the hydraulic circuit control device comprises: a drive motor, a drive cylinder having a drive cylinder piston moved by the drive motor, a driven cylinder having a drive cylinder piston and a hydraulic passage connecting the drive cylinder piston and the driven cylinder piston, the driven cylinder having a driven piston moved by the drive piston moving and increasing or decreasing the amount of hydraulic fluid in the driven cylinder through the hydraulic passage; and a hydraulic passage volume adjustment mechanism increasing or decreasing the volume of the hydraulic passage in accordance with the increase or decrease in the volume of the hydraulic fluid. fruit, The fluid path includes a main fluid path portion through which hydraulic fluid flows between the driven-side fluid chamber and the drive-side fluid chamber, and an adjustment fluid path portion connected to the main fluid path portion. The fluid path volume adjustment mechanism includes a volume adjustment motor that moves the inner wall surface of the adjustment fluid path portion, and is configured to increase or decrease the volume of the adjustment fluid path portion by moving the inner wall surface. .

[0022] The first aspect of this invention 3As described above, the molding machine according to this aspect includes a drive-side cylinder including a drive-side piston, a driven-side cylinder including a driven-side piston that is moved as the drive-side piston moves and the amount of hydraulic fluid in the driven-side fluid chamber increases or decreases through the fluid passage, and a fluid passage volume adjustment mechanism that increases or decreases the volume of the fluid passage in response to an increase or decrease in the volume of the hydraulic fluid. This allows the fluid passage volume adjustment mechanism to increase or decrease the volume of the fluid passage in response to an increase or decrease in the volume of the hydraulic fluid, even if an increase or decrease in the volume of the hydraulic fluid occurs due to temperature changes or leakage of the hydraulic fluid in the fluid passage, the driven-side fluid chamber, and the drive-side fluid chamber. Therefore, by increasing or decreasing the volume of the fluid passage using the fluid passage volume adjustment mechanism, an increase or decrease in the volume of the hydraulic fluid can be absorbed so that the increase or decrease in the volume of the hydraulic fluid does not affect the amount of movement of the driven-side piston. In other words, the amount of movement of the driven-side piston can be corrected so that the amount of movement of the driven-side piston relative to a predetermined amount of movement of the drive-side piston is maintained approximately constant. As a result, it is possible to provide a molding machine that can ensure the positional accuracy of the driven piston of the driven cylinder even if the volume of the working fluid fluctuates due to temperature changes or leakage of the working fluid. In addition, the volume of the adjustment liquid path section can be increased or decreased by moving the inner wall surface of the adjustment liquid path section using the volume adjustment motor, so the amount of movement of the driven side piston can be easily corrected and the positional accuracy of the driven side piston in the driven side cylinder can be easily ensured.

[0023] In the hydraulic circuit control device according to the first aspect and the molding machine according to the second aspect, the following configurations are also possible.

[0024] (Additional note 1) That is, the hydraulic circuit control device and the molding machine further include a hydraulic fluid cooling passage provided in the hydraulic passage and through which a refrigerant flows to cool the hydraulic fluid in the hydraulic passage.

[0025] With this configuration, the working fluid can be cooled by the working fluid cooling path, thereby suppressing the temperature rise of the working fluid and suppressing the volume change of the working fluid itself caused by the temperature rise of the working fluid. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a front view showing a press molding machine equipped with a hydraulic circuit control device according to an embodiment. [Figure 2]1 is a diagram showing the overall configuration of a hydraulic circuit control device according to an embodiment; [Figure 3] 3 is a diagram showing a fluid passage volume adjustment mechanism of the fluid pressure circuit control device according to the embodiment; FIG. [Figure 4] 10 is a diagram showing a fluid passage volume adjustment mechanism of a fluid pressure circuit control device according to a modified example. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, an embodiment will be described with reference to the drawings.

[0028] [Embodiment] (Configuration of press molding machine) The configuration of a press molding machine 100 (an example of the "molding machine" in the claims) equipped with a hydraulic circuit control device (hydraulic cylinder device) 101 according to an embodiment will be described with reference to FIGS.

[0029] As shown in Figure 1, the press molding machine 100 includes a fixed part 100a (bolster) to which a fixed mold M1 is attached, a movable part 100b (slide) to which a movable mold M2 is attached, and a hydraulic circuit control device 101 provided in the movable part 100b.

[0030] The press molding machine 100 is configured to open and close the fixed mold M1 and the movable mold M2 by moving the movable part 100b back and forth in the vertical direction (direction B) from above relative to the fixed part 100a using the hydraulic circuit control device 101.

[0031] (Configuration of hydraulic circuit control device) 2, the hydraulic circuit control device 101 includes a drive servomotor 1 (an example of the "drive motor" in the claims), a drive-side ball screw mechanism 2, a drive-side ball screw cooling path 3, a drive-side cylinder 4, a driven-side cylinder 5 including fluid paths 50 and 51 connected to the drive-side cylinder 4, a hydraulic fluid cooling path 6 (see FIG. 3), and a fluid path volume adjustment mechanism 7. One fluid path volume adjustment mechanism 7 is provided for each of the fluid paths 50 and 51.

[0032] The driving cylinder 4 and the driven cylinder 5 are configured to exchange hydraulic fluid through hydraulic paths 50 and 51 when moving the movable part 100b forward or backward. The hydraulic circuit control device 101 is configured to move the driven piston 53 of the driven cylinder 5 forward or backward by moving the driving piston 41 of the driving cylinder 4 forward or backward. The driven cylinder 5 has the movable part 100b of the press molding machine 100 attached to the tip of the driven piston 53 in the forward direction (direction B1), and is configured to generate a propulsive force within the hydraulic circuit control device 101 that ultimately moves the movable part 100b forward or backward. Note that, as an example, the hydraulic fluid is a liquid such as oil or water.

[0033] Here, the cross-sectional area of ​​the driven-side cylinder 5 in a cross section perpendicular to the moving direction of the driven-side piston 53 is larger than the cross-sectional area of ​​the driving-side piston 41 in the driving-side cylinder 4 in a cross section perpendicular to the moving direction. Therefore, the hydraulic circuit control device 101 is configured to be able to generate a large thrust for moving the movable part 100b by using the driving-side piston 41 and the driven-side piston 53 to perform boosting. Note that the cross-sectional area of ​​the driven-side piston may be less than or equal to the cross-sectional area of ​​the driving-side piston. When the cross-sectional area of ​​the driven-side piston is smaller than the cross-sectional area of ​​the driving-side piston, the moving speed (moving amount) of the driven-side piston is greater than the moving speed (moving amount) of the driving-side piston.

[0034] In each drawing, the movement direction of the drive-side piston 41 is indicated by direction A, the forward direction of direction A is indicated by direction A1, and the backward direction of direction A is indicated by direction A2. In addition, the axis extending in direction A and positioned at the center of the drive-side piston 41 and drive-side ball screw 21 is indicated by central axis α.

[0035] In each drawing, the movement direction of the driven-side piston 53 is indicated by direction B, the forward direction of direction B is indicated by direction B1, and the backward direction of direction B is indicated by direction B2. Note that direction B is also the movement direction of the movable part 100b of the press molding machine 100.

[0036] In each drawing, the movement direction of the volume adjustment piston 72 of the liquid path volume adjustment mechanism 7 is indicated by direction C, the forward direction of direction C is indicated by direction C1, and the backward direction of direction C is indicated by direction C2. When the volume adjustment piston 72 moves in direction C1, the volume of the liquid path 50 (51) decreases, and when the volume adjustment piston 72 moves in direction C2, the volume of the liquid path 50 (51) increases.

[0037] (Drive servo motor configuration) The drive servo motor 1 is configured to move the drive-side piston 41 of the drive-side cylinder 4 back and forth in direction A via the drive-side ball screw mechanism 2. The drive-side cylinder 4 is provided with a position detector 73a (an example of a "detector for movement adjustment" in the claims) that detects the position of the drive-side piston 41. The drive servo motor 1 is provided with a control unit 1a that controls the drive of the drive servo motor 1. The control unit 1a is configured to obtain the detection result of the position detector 73a through feedback and adjust the drive of the drive servo motor 1. In short, the fluid path volume adjustment mechanism 7 is configured to increase or decrease the volume of the fluid paths 50, 51 based on the piston position, which is a state indicator value that directly indicates an increase or decrease in the volume of the hydraulic fluid. The fluid path volume adjustment mechanism 7 is also configured to increase or decrease the volume of the fluid paths 50, 51 based on the temperature of the hydraulic fluid, which is a state indicator value that indirectly indicates an increase or decrease in the volume of the hydraulic fluid. Note that the state indicator value that directly indicates an increase or decrease in the volume of the hydraulic fluid is not limited to the piston position. Furthermore, the indicator value of the state that indirectly indicates an increase or decrease in the volume of the working fluid is not limited to the temperature of the working fluid, but may be the pressure of the working fluid or the like.

[0038] The control unit 1a includes a computer numerical control (CNC) device that generates pulse signals for driving the drive servo motor 1, and a servo amplifier (driver) that drives the drive servo motor 1 based on the pulse signals.

[0039] The drive servo motor 1 includes a motor body 10 having a core, and a rotary shaft 11 (output shaft) that is rotated about a central axis α by the motor body 10. A through hole 12 extending along the central axis α is formed in the motor body 10 and the rotary shaft 11. Inside the through hole 12, a refrigerant supply pipe 3a that supplies refrigerant to the drive-side ball screw cooling path 3 and a refrigerant discharge pipe 3b that discharges refrigerant from the drive-side ball screw cooling path 3 are arranged.

[0040] (Configuration of the drive side ball screw mechanism) The drive-side ball screw mechanism 2 connects the drive servo motor 1 and the drive-side piston 41 of the drive-side cylinder 4. The drive-side ball screw mechanism 2 includes a drive-side rotating nut 20 and a drive-side ball screw 21. The drive-side ball screw mechanism 2 is configured to be driven by the drive servo motor 1 to move the drive-side piston 41 together with the drive-side ball screw 21 back and forth in the A direction.

[0041] The drive-side rotating nut 20 is attached to the rotating shaft 11 of the drive servo motor 1. Therefore, the drive-side rotating nut 20 is configured to rotate together with the rotating shaft 11 around the central axis α while maintaining its position in the A direction without moving in the A direction. The drive-side ball screw 21 extends in the A direction while always being threadedly engaged with the drive-side rotating nut 20. A drive-side piston 41 is attached to the end of the drive-side ball screw 21 in the A1 direction. The drive-side ball screw 21 is arranged coaxially (on the central axis α) with the drive-side piston 41 of the drive-side cylinder 4. The drive-side ball screw 21 is configured to move in the A direction without rotating when the rotating shaft 11 rotates.

[0042] (Configuration of the drive side ball screw cooling passage) The drive-side ball screw cooling passage 3 is provided inside the drive-side ball screw 21. The drive-side ball screw cooling passage 3 is configured so that a refrigerant that cools the drive-side ball screw 21 flows through it. As an example, the drive-side ball screw cooling passage 3 is an elongated U-shaped passage that extends along the longitudinal direction (direction A) of the drive-side ball screw 21. The drive-side ball screw cooling passage 3 is connected to a refrigerant supply pipe 3a and a refrigerant discharge pipe 3b at the end of the drive-side ball screw 21 in the A2 direction, and is formed so as to turn back near the end of the drive-side ball screw 21 in the A1 direction.

[0043] The temperature of the drive-side ball screw 21 may rise significantly when it moves at high speed together with the drive-side piston 41. In such a case, the drive-side ball screw cooling path 3 cools the drive-side ball screw 21 and suppresses expansion of the drive-side ball screw 21, thereby suppressing obstruction of movement of the drive-side ball screw 21 by the drive-side rotation nut 20 with which the drive-side ball screw 21 is threaded. In addition, the drive-side ball screw cooling path 3 suppresses a rise in the temperature of the working fluid around the drive-side piston 41 attached to the drive-side ball screw 21, via the drive-side piston 41, which is attached to the drive-side ball screw 21, from rising due to a rise in temperature of the drive-side ball screw 21.

[0044] (Configuration of the driving cylinder) The drive-side cylinder 4 includes a drive-side cylindrical portion 40, a drive-side piston 41 that is moved by the drive servo motor 1, and drive-side fluid chambers 42a and 42b. The drive-side cylindrical portion 40 and the drive-side piston 41 are provided with an oil seal S1 that prevents (suppresses) leakage of the hydraulic fluid.

[0045] The drive-side cylinder portion 40 is a hollow housing that accommodates the drive-side piston 41 in a state where it can move in the front-to-rear direction (direction A) and has drive-side fluid chambers 42a and 42b provided therein. A position detection unit 73a that detects the position of the drive-side piston 41 is also provided inside the drive-side cylinder portion 40. The position detection unit 73a is a non-contact detection unit that detects the distance from the position detection unit 73a to the drive-side piston 41 using, for example, light or magnetism.

[0046] The drive-side piston 41 divides the internal space of the drive-side cylinder portion 40 into a drive-side fluid chamber 42a on the A1 direction side and a drive-side fluid chamber 42b on the A2 direction side. Therefore, the hydraulic fluid in the drive-side fluid chamber 42a and the hydraulic fluid in the drive-side fluid chamber 42b do not mix with each other.

[0047] When the driving side piston 41 moves forward (in the direction A1), hydraulic fluid flows out from the driving side fluid chamber 42a to the driven side cylinder 5 (driven side fluid chamber 54b) through fluid passage 50, and hydraulic fluid flows into the driving side fluid chamber 42b from the driven side cylinder 5 (driven side fluid chamber 54a) through fluid passage 51.

[0048] In addition, when the driving side piston 41 moves backward (towards A2), hydraulic fluid flows from the driven side cylinder 5 (driven side fluid chamber 54b) to the driving side fluid chamber 42a via the fluid path 50, and hydraulic fluid flows out from the driving side fluid chamber 42b to the driven side cylinder 5 (driven side fluid chamber 54a) via the fluid path 50.

[0049] (Configuration of driven cylinder) The driven-side cylinder 5 includes fluid passages 50 and 51, a driven-side cylindrical portion 52, a driven-side piston 53, and driven-side fluid chambers 54a and 54b. The driven-side cylindrical portion 52 and the driven-side piston 53 are provided with an oil seal S2 that prevents (suppresses) leakage of the hydraulic fluid.

[0050] The fluid passage 50 connects the drive-side fluid chamber 42a and the driven-side fluid chamber 54b. The fluid passage 50, the drive-side fluid chamber 42a, and the driven-side fluid chamber 54b form a closed circuit that allows hydraulic fluid to flow between the drive-side fluid chamber 42a and the driven-side fluid chamber 54b without changing the total amount of hydraulic fluid therein. This closed circuit is filled with hydraulic fluid. However, the total amount of hydraulic fluid in the fluid passage 50, the drive-side fluid chamber 42a, and the driven-side fluid chamber 54b may decrease over time due to leakage of hydraulic fluid through the oil seals S1 to S3.

[0051] Fluid passage 51 connects drive-side fluid chamber 42b and driven-side fluid chamber 54a. Fluid passage 51, drive-side fluid chamber 42b, and driven-side fluid chamber 54a form a closed circuit that allows hydraulic fluid to flow between drive-side fluid chamber 42b and driven-side fluid chamber 54a without changing the total amount of hydraulic fluid therein. This closed circuit is filled with hydraulic fluid. However, the total amount of hydraulic fluid in fluid passage 51, drive-side fluid chamber 42b, and driven-side fluid chamber 54a may decrease over time due to leakage of hydraulic fluid through oil seals S1 to S3. Fluid passages 50 and 51 are provided with a plug V (see FIG. 3) for replenishing hydraulic fluid lost due to leakage.

[0052] The fluid path 50 includes a main fluid path portion 5a through which the hydraulic fluid flows between the driven-side fluid chamber 54b and the drive-side fluid chamber 42a, and an adjustment fluid path portion 5b (see FIG. 3) connected to the main fluid path portion 5a. The adjustment fluid path portion 5b is disposed outside the driven-side cylinder portion 52 and the drive-side cylinder portion 40.

[0053] The main fluid path section 5a is formed by a long, narrow pipe through which the hydraulic fluid passes. The main fluid path section 5a is a flow path whose inner wall surface is fixed and does not move, and is configured so that its volume does not increase or decrease.

[0054] The adjustment liquid path section 5b is configured such that a portion of its inner wall surface W is movable, and the volume increases or decreases with the movement of the inner wall surface W. The inner wall surface W of the adjustment liquid path section 5b is configured by the front surface (the surface on the liquid path 50 side) of a volume adjustment piston 72 (described later) of the liquid path volume adjustment mechanism 7. The adjustment liquid path section 5b is connected to the main liquid path section 5a from the side (the intersecting direction) and is a convex space protruding laterally from the main liquid path section 5a. The adjustment liquid path section 5b extends in the C direction while maintaining a cross-sectional shape perpendicular to the C direction. In other words, the extension direction of the adjustment liquid path section 5b and the extension direction of the main liquid path section 5a are approximately perpendicular. As an example, the adjustment liquid path section 5b is a cylindrical hollow space extending in the C direction. The liquid path 51 is also configured similarly to the liquid path 50 and includes the main liquid path section 5a and the adjustment liquid path section 5b.

[0055] The driven-side cylinder portion 52 is a hollow housing that accommodates the driven-side piston 53 inside in a state where it can move back and forth (direction B), and that has driven-side liquid chambers 54a and 54b provided inside. Also, a position detection unit 73b that detects the position of the driven-side piston 53 is provided inside the driven-side cylinder portion 52. The position detection unit 73b is a non-contact detection unit that detects the distance from the position detection unit 73b to the driven-side piston 53, for example, using light or magnetism.

[0056] The driven-side piston 53 divides the internal space of the driven-side tubular portion 52 into a driven-side fluid chamber 54a on the B1 direction side and a driven-side fluid chamber 54b on the B2 direction side. Therefore, the hydraulic fluid in the driven-side fluid chamber 54a and the hydraulic fluid in the driven-side fluid chamber 54b do not mix with each other. The driven-side piston 53 is configured to move as the drive-side piston 41 moves and the amount of hydraulic fluid in the driven-side fluid chambers 54a and 54b increases or decreases via the fluid paths 50 and 51.

[0057] Specifically, when the drive-side piston 41 moves forward (in the direction A1), hydraulic fluid flows from the drive-side fluid chamber 42a to the driven-side fluid chamber 54b via the fluid path 50, increasing the amount of hydraulic fluid in the driven-side fluid chamber 54b, and hydraulic fluid flows from the driven-side fluid chamber 54a to the drive-side fluid chamber 42b via the fluid path 51, decreasing the amount of hydraulic fluid in the driven-side fluid chamber 54a. As a result, the driven-side piston 53 moves forward (in the direction B1) together with the movable part 100b of the press molding machine 100. This causes the fixed mold M1 (see FIG. 1) and the movable mold M2 to be clamped together.

[0058] Furthermore, when the drive-side piston 41 moves rearward (in the direction A2), hydraulic fluid flows out from the driven-side fluid chamber 54b to the drive-side fluid chamber 42a via the fluid path 50, decreasing the amount of hydraulic fluid in the driven-side fluid chamber 54b, and hydraulic fluid flows from the drive-side fluid chamber 42b to the driven-side fluid chamber 54a via the fluid path 51, increasing the amount of hydraulic fluid in the driven-side fluid chamber 54a. As a result, the driven-side piston 53 moves rearward (in the direction B2) together with the movable part 100b of the press molding machine 100. This causes the fixed mold M1 and the movable mold M2 to open.

[0059] (Configuration of working fluid cooling path) The working fluid cooling path 6 (see FIG. 3) is provided in the liquid paths 50 and 51, and is configured so that a refrigerant flows through it to cool the working fluid in the liquid paths 50 and 51. The working fluid cooling path 6 is disposed outside the liquid paths 50 and 51, while being in contact with the liquid paths 50 and 51. The working fluid cooling path 6 is spirally wound around the liquid paths 50 and 51. The working fluid cooling path 6 is made of a material with a high heat transfer coefficient. As an example, the working fluid cooling path 6 is made of copper.

[0060] (Configuration of liquid path volume adjustment mechanism) The fluid passage volume adjustment mechanism 7 is configured to increase or decrease the volume of the fluid passage 50 (51) in response to an increase or decrease in the volume of the hydraulic fluid. As a result, the fluid passage volume adjustment mechanism 7 is configured to perform control to maintain a substantially constant amount of movement of the driven-side piston 53 relative to a predetermined amount of movement of the drive-side piston 41. The increase or decrease in the volume of the hydraulic fluid occurs due to factors such as leakage of the hydraulic fluid from the oil seals S1 to S3 and expansion or contraction of the hydraulic fluid due to temperature changes of the hydraulic fluid.

[0061] As an example, let us assume that the forward movement (direction B1) of the driven-side piston 53 is set to 50 mm relative to the forward movement (direction A1) of 100 mm of the driving-side piston 41. If the actual forward movement (direction B1) of the driven-side piston 53 becomes 52 mm instead of 50 mm due to expansion of the hydraulic fluid, the fluid path volume adjustment mechanism 7 is configured to move the volume adjustment piston 72 (inner wall surface W) backward to increase the volume of the adjustment fluid path section 5b. As a result, the expanded volume of the hydraulic fluid is absorbed by the enlarged adjustment fluid path section 5b, and the movement of the driven-side piston 53 relative to the predetermined movement of the driving-side piston 41 is maintained approximately constant.

[0062] The liquid path volume adjustment mechanism 7 includes a volume adjustment servo motor 70 (an example of the "volume adjustment motor" in the claims), a volume adjustment ball screw mechanism 71, a volume adjustment piston 72, a position detection unit 73a, a position detection unit 73b (an example of the "movement adjustment detection unit" in the claims), a liquid temperature detection unit 73c (an example of the "movement adjustment detection unit" in the claims), a liquid pressure detection unit 73d (an example of the "movement adjustment detection unit" in the claims), and a control unit 74.

[0063] The volume adjustment piston 72 is provided in the adjustment liquid path portion 5b of the liquid path 50 (51). The position detection unit 73a, the position detection unit 73b, the liquid temperature detection unit 73c, and the liquid pressure detection unit 73d are detection units for adjusting the amount of movement of the driven-side piston 53 relative to the movement of the drive-side piston 41. The liquid path volume adjustment mechanism 7 is configured to adjust the volume of the liquid path 50 (adjustment liquid path portion 5b) based on the detection results of the position detection unit 73a, the position detection unit 73b, the liquid temperature detection unit 73c, and the liquid pressure detection unit 73d.

[0064] 3, the volume adjustment servomotor 70 is configured to move a volume adjustment piston 72 back and forth in direction C via a volume adjustment ball screw mechanism 71. The drive of the volume adjustment servomotor 70 is controlled by a control unit 74.

[0065] The volume adjustment ball screw mechanism 71 connects the volume adjustment servomotor 70 and the volume adjustment piston 72. The volume adjustment ball screw mechanism 71 includes a volume adjustment rotating nut 71a and a volume adjustment ball screw 71b.

[0066] The volume adjustment ball screw mechanism 71 is configured to be driven by a volume adjustment servo motor 70, and to move the volume adjustment piston 72 back and forth in direction C together with the volume adjustment ball screw 71b. The volume adjustment rotating nut 71a is attached to the rotating shaft 70a (output shaft) of the volume adjustment servo motor 70. Therefore, the volume adjustment rotating nut 71a is configured to rotate together with the rotating shaft 70a while maintaining its position in direction C without moving in direction C.

[0067] A volume adjustment piston 72 is attached to the end of the volume adjustment ball screw 71b in the C1 direction. The liquid path volume adjustment mechanism 7 is configured to increase or decrease the volume of the liquid path 50 (51) by moving the volume adjustment piston 72 (inner wall surface W) in the C direction together with the volume adjustment ball screw 71b.

[0068] The volume adjustment ball screw 71b extends in the C direction while always being threadedly engaged with the volume adjustment rotating nut 71a. A volume adjustment piston 72 is attached to the C1-direction end of the volume adjustment ball screw 71b. The front surface (the surface facing the C1 direction) of the volume adjustment piston 72 forms the inner wall surface W of the adjustment liquid path section 5b. An oil seal S3 is provided on the volume adjustment piston 72.

[0069] The volume adjustment piston 72 separates the adjustment liquid path portion 5b, which is the space on the C1 side that is filled with hydraulic fluid, from the space on the C2 side into which hydraulic fluid does not flow. The volume adjustment piston 72 is configured to move the inner wall surface W in the C direction to increase or decrease the volume of the adjustment liquid path portion 5b.

[0070] For example, when the volume adjustment rotating nut 71a rotates in one direction (the R1 direction indicated by the white arrow), the volume adjustment piston 72 moves in the C2 direction, increasing the volume of the adjustment liquid path section 5b. Since the volume of the main liquid path section 5a does not change, the volume of the entire liquid path 50 (51) also increases by the amount that the adjustment liquid path section 5b becomes larger.

[0071] Furthermore, when the volume adjustment rotating nut 71a rotates in the other rotation direction (the R2 rotation direction indicated by the black arrow), the volume adjustment piston 72 moves in the C1 direction, reducing the volume of the adjustment liquid path section 5b. Since the volume of the main liquid path section 5a does not change, the volume of the entire liquid path 50 also reduces by the amount that the adjustment liquid path section 5b becomes smaller.

[0072] 2 is configured to detect the position of the drive-side piston 41. As described above, the position detection unit 73b is provided inside the drive-side cylinder portion 40. The detection value of the position detection unit 73b is acquired by the control unit 1a and the control unit 74.

[0073] The position detection unit 73a is configured to detect the position of the driven-side piston 53. The position detection unit 73a is provided inside the driven-side cylinder portion 52. The detection value of the position detection unit 73a is acquired by the control unit 74.

[0074] The fluid temperature detector 73c is configured to detect the temperature (state) of the hydraulic fluid. The fluid temperature detector 73c is provided in the fluid path 50 (51). The detection value of the fluid temperature detector 73c is acquired by the control unit 74.

[0075] The hydraulic pressure detection unit 73d is configured to detect the pressure (state) of the hydraulic fluid. The hydraulic pressure detection unit 73d is provided in the hydraulic passage 50 (51). The detection value of the hydraulic pressure detection unit 73d is acquired by the control unit 74.

[0076] The control unit 74 is configured to obtain the detection results of the position detection unit 73a, the position detection unit 73b, the liquid temperature detection unit 73c, and the liquid pressure detection unit 73d through feedback, and adjust the drive of the volume adjustment servomotor 70. The control unit 74 includes a computer numerical control (CNC) device that generates a pulse signal for driving the volume adjustment servomotor 70, and a servo amplifier (driver) that drives the volume adjustment servomotor 70 based on the pulse signal.

[0077] (Control configuration of the control unit) The control configuration of the control unit 74 will be described.

[0078] When the control unit 74 determines, based on the detection values ​​of the position detectors 73a and 73b, that the displacement of the driven-side piston 53 relative to the predetermined displacement of the drive-side piston 41 is smaller than the set value (reference value) when there is no change in the temperature of the hydraulic fluid, the control unit 74 controls the volume adjustment piston 72 (inner wall surface W) to move (advance) in the C1 direction to reduce the volume of the adjustment fluid path section 5b. That is, the control unit 74 controls the hydraulic fluid in the adjustment fluid path section 5b to be pushed into the main fluid path section 5a. In this case, the decrease in the volume of the adjustment fluid path section 5b is approximately equal to the decrease in the volume of the driven-side fluid chamber 54a (driven-side fluid chamber 54b) calculated based on the displacement of the driven-side piston 53 that is smaller than the set value. As a result, the displacement of the driven-side piston 53 relative to the predetermined displacement of the drive-side piston 41 is corrected to the set value. When there is no change in the temperature of the hydraulic fluid, the movement amount of the driven piston 53 relative to the predetermined movement amount of the driving piston 41 may become smaller than the set value due to, for example, leakage of the hydraulic fluid.

[0079] In addition, when the control unit 74 determines that the temperature of the working fluid is lower than the set value based on the detection value of the fluid temperature detection unit 73c when there is no leakage of working fluid, it is configured to control the volume adjustment piston 72 (inner wall surface W) to move (advance) in the C1 direction, taking into account the contraction rate of the working fluid in response to the temperature drop, thereby reducing the volume of the adjustment fluid path unit 5b.

[0080] In addition, when the control unit 74 determines that the temperature of the working fluid is higher than the set value based on the detection value of the fluid temperature detection unit 73c when there is no leakage of working fluid, it is configured to control the volume adjustment piston 72 (inner wall surface W) to move (reverse) in the C2 direction, taking into account the expansion rate of the working fluid in response to the temperature increase, thereby increasing the volume of the adjustment fluid path unit 5b.

[0081] Furthermore, when the control unit 74 determines, based on the detection value of the fluid pressure detection unit 73d, that the pressure of the hydraulic fluid is (significantly) lower than the set value (when the control unit 74 determines that the pressure is lower than a predetermined threshold value), the control unit 74 moves (advances) the volume adjustment piston 72 (inner wall surface W) in the C1 direction to increase the volume of the adjustment fluid path unit 5b. Note that when the pressure of the hydraulic fluid is (significantly) lower than the set value (when the control unit 74 determines that the pressure is lower than a predetermined threshold value), the propulsive force of the movable part 100b, which moves together with the driven-side piston 53, is insufficient, and the clamping force of the fixed mold M1 and the movable mold M2 is not fully exerted.

[0082] (Effects of this embodiment) In this embodiment, the following effects can be obtained.

[0083] As described above, this embodiment includes the drive-side cylinder 4 including the drive-side piston 41, the driven-side cylinder 5 including the driven-side piston 53 that is moved as the drive-side piston 41 moves and the amount of hydraulic fluid in the driven-side fluid chambers 54a, 54b increases or decreases through the fluid paths 50, 51, and the fluid path volume adjustment mechanism 7 increases or decreases the volume of the fluid paths 50, 51 in accordance with the increase or decrease in the volume of the hydraulic fluid. As a result, even if the volume of the hydraulic fluid increases or decreases due to temperature changes or leakage of the hydraulic fluid in the fluid paths 50, 51, the driven-side fluid chambers 54a, 54b, and the drive-side fluid chambers 42a, 42b, the fluid path volume adjustment mechanism 7 can increase or decrease the volume of the fluid paths 50, 51 in accordance with the increase or decrease in the volume of the hydraulic fluid. Therefore, by increasing or decreasing the volume of the fluid paths 50, 51 using the fluid path volume adjustment mechanism 7, the increase or decrease in the volume of the hydraulic fluid can be absorbed so that the increase or decrease in the volume of the hydraulic fluid does not affect the amount of movement of the driven-side piston 53. That is, the amount of movement of the driven-side piston 53 can be corrected so that the amount of movement of the driven-side piston 53 is maintained substantially constant relative to a predetermined amount of movement of the drive-side piston 41. As a result, even if the volume of the working fluid fluctuates due to temperature changes or leakage of the working fluid, the positional accuracy of the driven-side piston 53 of the driven-side cylinder 5 can be ensured.

[0084] In this embodiment, as described above, the fluid paths 50, 51 include a main fluid path portion 5a that allows hydraulic fluid to flow between the driven-side fluid chambers 54a, 54b and the drive-side fluid chambers 42a, 42b, and an adjustment fluid path portion 5b connected to the main fluid path portion 5a, and the fluid path volume adjustment mechanism 7 includes a volume adjustment servomotor 70 that moves the inner wall surface W of the adjustment fluid path portion 5b, and is configured to increase or decrease the volume of the adjustment fluid path portion 5b by moving the inner wall surface W. This allows the volume adjustment servomotor 70 to move the inner wall surface W of the adjustment fluid path portion 5b to increase or decrease the volume of the adjustment fluid path portion 5b, so that the movement amount of the driven-side piston 53 can be easily corrected and the positional accuracy of the driven-side piston 53 of the driven-side cylinder 5 can be easily ensured.

[0085] In the present embodiment, as described above, the fluid passage volume adjustment mechanism 7 includes movement adjustment detectors (position detectors 73a, 73b, fluid temperature detector 73c, fluid pressure detector 73d) that detect at least one of the positions of the driven-side piston 53 and the driving-side piston 41 and the state of the hydraulic fluid in order to adjust the amount of movement of the driven-side piston 53 relative to the movement of the driving-side piston 41, and is configured to increase or decrease the volume of the fluid passages 50, 51 based on the detection results of the movement adjustment detectors. This allows the movement amount of the driven-side piston 53 to be corrected based on the detection results of at least one of the positions of the driven-side piston 53 and the driving-side piston 41 and the state of the hydraulic fluid by the movement adjustment detectors, making it possible to more reliably ensure the positional accuracy of the driven-side piston 53 of the driven-side cylinder 5 in accordance with the positions of the driven-side piston 53 and the driving-side piston 41 and the state of the hydraulic fluid.

[0086] In this embodiment, as described above, the movement adjustment detector includes at least one of position detectors 73a, 73b that detect the positions of drive-side piston 41 and driven-side piston 53, a fluid temperature detector 73c that detects the temperature of the hydraulic fluid, and a fluid pressure detector 73d that detects the pressure of the hydraulic fluid, and the fluid path volume adjustment mechanism 7 is configured to increase or decrease the volume of the fluid paths 50, 51 based on the detection results of at least one of the position detectors 73a, 73b, the fluid pressure detector 73d, and the fluid temperature detector 73c. ​​This allows the detection of either the positions of drive-side piston 41 and driven-side piston 53, which indicate a change in the amount of movement of driven-side piston 53 (deviation from a set value), or the temperature and pressure of the hydraulic fluid, which affect the change in the amount of movement of driven-side piston 53, and makes it possible to appropriately correct the amount of movement of driven-side piston 53 according to various situations.

[0087] In this embodiment, as described above, the liquid path volume adjustment mechanism 7 includes a volume adjustment ball screw mechanism 71 having a volume adjustment piston 72 provided in the liquid paths 50, 51 and a volume adjustment ball screw 71b to which the volume adjustment piston 72 is attached, and which increases or decreases the volume of the liquid paths 50, 51 by moving the volume adjustment piston 72 together with the volume adjustment ball screw 71b. This allows the volume adjustment ball screw mechanism 71 to move the volume adjustment piston 72, so that the volume adjustment piston 72 can be moved with precision, thereby enabling the volume of the adjustment liquid path section 5b to be precisely adjusted.

[0088] As described above, this embodiment further includes a drive-side ball screw mechanism 2 that has a drive-side ball screw 21 to which a drive-side piston 41 is attached and is driven by a drive servo motor 1 to move the drive-side piston 41 together with the drive-side ball screw 21, and a drive-side ball screw cooling passage 3 that is provided inside the drive-side ball screw 21 and through which a refrigerant flows to cool the drive-side ball screw 21. As a result, the drive-side ball screw 21 to which the drive-side piston 41 is attached can be cooled by the drive-side ball screw cooling passage 3, which suppresses a temperature rise of the working fluid via the drive-side ball screw 21 and the drive-side piston 41, and thereby suppresses a change in the volume of the working fluid itself that would be caused by a temperature rise of the working fluid.

[0089] As described above, this embodiment further includes a working fluid cooling path 6 that is provided in the fluid paths 50, 51 and through which a refrigerant flows to cool the working fluid in the fluid paths 50, 51. This allows the working fluid to be cooled by the working fluid cooling path 6, thereby suppressing a temperature rise in the working fluid and suppressing a change in the volume of the working fluid itself that would otherwise be caused by a temperature rise in the working fluid.

[0090] In this embodiment, as described above, the fluid passage volume adjustment mechanism 7 is configured to increase or decrease the volume of the fluid passages 50, 51 based on both the state indicator value that directly indicates an increase or decrease in the volume of the hydraulic fluid and the state indicator value that indirectly indicates an increase or decrease in the volume of the hydraulic fluid. This allows the volume of the hydraulic fluid to be increased or decreased with greater accuracy by taking into account both the state indicator value that directly indicates an increase or decrease in the volume of the hydraulic fluid and the state indicator value that indirectly indicates an increase or decrease in the volume of the hydraulic fluid. As a result, the positional accuracy of the driven-side piston 53 of the driven-side cylinder 5 can be improved.

[0091] [Variations] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not by the description of the above embodiments, and further includes all modifications (variations) within the meaning and scope of the claims.

[0092] For example, in the above embodiment, an example was shown in which the volume adjustment piston of the fluid path volume adjustment mechanism was directly attached to the tip (end in the C1 direction) of the volume adjustment ball screw, but the present invention is not limited to this. In the present invention, as in the hydraulic circuit control device 201 shown in Fig. 4, a plate member 272a may be directly attached to the tip (end in the C1 direction) of the volume adjustment ball screw 71b, and a spring member 272b may be provided between the plate member 272a and the volume adjustment piston 272. The spring member 272b enables the hydraulic circuit control device 201 to absorb (cushion) impacts applied to the driven-side piston.

[0093] In the above embodiment, the molding machine of the present invention is configured as a press molding machine, but the present invention is not limited to this. In the present invention, the molding machine may be configured as an injection molding machine, a die-casting machine, or the like.

[0094] In the above embodiment, the hydraulic circuit control device is provided in a press molding machine (molding machine), but the present invention is not limited to this. In the present invention, the hydraulic circuit control device may be provided in a machine tool, an inspection device, or the like.

[0095] In the above embodiment, the driving-side fluid chamber on the front side of the driving-side piston and the driven-side fluid chamber on the rear side of the driven-side piston are connected by one fluid path, and the driving-side fluid chamber on the rear side of the driving-side piston and the driven-side fluid chamber on the front side of the driven-side piston are connected by the other fluid path, but the present invention is not limited to this. In the present invention, the driving-side fluid chamber on the front side of the driving-side piston and the driven-side fluid chamber on the front side of the driven-side piston may be connected by one fluid path, and the driving-side fluid chamber on the rear side of the driving-side piston and the driven-side fluid chamber on the rear side of the driven-side piston may be connected by the other fluid path.

[0096] In the above embodiment, the working fluid cooling passage is disposed outside the fluid passage, but the present invention is not limited to this. In the present invention, the working fluid cooling passage may be disposed inside the fluid passage so that the working fluid cooling passage is in direct contact with the working fluid.

[0097] In the above embodiment, the drive motor of the present invention is configured as a servo motor, but the present invention is not limited to this. In the present invention, the drive motor may be configured as a different type of motor, such as a stepping motor.

[0098] In the above embodiment, the fluid path includes two types of portions, a main fluid path portion and an adjustment fluid path portion, but the present invention is not limited to this. In the present invention, the fluid path may include only a fluid path portion (main fluid path portion) through which hydraulic fluid flows between the driven-side fluid chamber and the drive-side fluid chamber. In other words, the fluid path volume adjustment mechanism may be configured to move the inner wall surface of the fluid path portion (main fluid path portion) through which hydraulic fluid flows between the driven-side fluid chamber and the drive-side fluid chamber.

[0099] In the above embodiment, the hydraulic circuit control device is provided with two hydraulic passage volume adjustment mechanisms, but the present invention is not limited to this. In the present invention, the hydraulic circuit control device may be provided with one hydraulic passage volume adjustment mechanism, or three or more hydraulic passage volume adjustment mechanisms.

[0100] Furthermore, in the above embodiment, an example was shown in which the volume adjustment piston was attached to the volume adjustment ball screw and moved in the C direction together with the volume adjustment ball screw, but the present invention is not limited to this. In the present invention, the volume adjustment piston may be attached to a volume adjustment rotating nut and moved in the C direction together with the volume adjustment rotating nut. In this case, the volume adjustment ball screw mechanism is configured so that the volume adjustment ball screw does not move in the C direction.

[0101] In addition, in the above embodiment, an example was shown in which the liquid path volume adjustment mechanism is configured to increase or decrease the volume of the liquid path based on both a state index value that directly indicates an increase or decrease in the volume of the working fluid and a state index value that indirectly indicates an increase or decrease in the volume of the working fluid, but the liquid path volume adjustment mechanism may also be configured to increase or decrease the volume of the liquid path based on only one of a state index value that directly indicates an increase or decrease in the volume of the working fluid and a state index value that indirectly indicates an increase or decrease in the volume of the working fluid. [Explanation of symbols]

[0102] 1 Drive servo motor (drive motor) 2. Drive side ball screw mechanism 3 Drive side ball screw cooling passage 4 Drive side cylinder 5 Driven cylinder 5a Main liquid path 5b Adjustment liquid path 7 Liquid channel volume adjustment mechanism 21 Drive side ball screw 41 Drive side piston 42a, 42b Drive side fluid chamber 50, 51 Liquid path 53 Driven side piston 54a, 54b Driven side liquid chamber 70 Volume adjustment servo motor (volume adjustment motor) 71 Ball screw mechanism for volume adjustment 71b Volume adjustment ball screw 72, 272 Volume adjustment piston 73a (detects the position of the drive-side piston) position detector (detector for movement adjustment) 73b Position detector (detector for movement adjustment) (detects the position of the driven piston) 73c Liquid temperature detector (detector for moving adjustment) 73d Liquid pressure detector (detector for movement adjustment) 100 Press molding machine (molding machine) 100a fixed part 100b Moving part 101, 201 Hydraulic circuit control device M1 Fixed mold M2 movable mold W inner wall

Claims

1. A drive motor; a drive-side cylinder including a drive-side fluid chamber and a drive-side piston moved by the drive motor; a driven-side cylinder including a driven-side fluid chamber, a fluid passage connecting the driven-side fluid chamber and the drive-side fluid chamber, and a driven-side piston that is moved as the drive-side piston moves and the amount of hydraulic fluid in the driven-side fluid chamber increases or decreases via the fluid passage; a fluid passage volume adjustment mechanism that increases or decreases the volume of the fluid passage in accordance with an increase or decrease in the volume of the hydraulic fluid, the fluid path includes a main fluid path portion through which the hydraulic fluid flows between the driven-side fluid chamber and the drive-side fluid chamber, and an adjustment fluid path portion connected to the main fluid path portion; A hydraulic circuit control device, wherein the liquid path volume adjustment mechanism includes a volume adjustment motor that moves the inner wall surface of the adjustment liquid path section, and is configured to move the inner wall surface to increase or decrease the volume of the adjustment liquid path section.

2. 2. The hydraulic circuit control device according to claim 1, wherein the fluid path volume adjustment mechanism includes a movement adjustment detection unit that detects at least one of the positions of the driven side piston and the driving side piston and the state of the hydraulic fluid in order to adjust the amount of movement of the driven side piston relative to the movement of the driving side piston, and is configured to increase or decrease the volume of the fluid path based on the detection result of the movement adjustment detection unit.

3. the movement adjustment detector includes at least one of a position detector that detects positions of the driving piston and the driven piston, a fluid temperature detector that detects the temperature of the hydraulic fluid, and a fluid pressure detector that detects the pressure of the hydraulic fluid; 3. The hydraulic circuit control device according to claim 2, wherein the hydraulic passage volume adjustment mechanism is configured to increase or decrease the volume of the hydraulic passage based on detection results of at least one of the position detection unit, the hydraulic pressure detection unit, and the hydraulic temperature detection unit.

4. A drive motor; a drive-side cylinder including a drive-side fluid chamber and a drive-side piston moved by the drive motor; a driven-side cylinder including a driven-side fluid chamber, a fluid passage connecting the driven-side fluid chamber and the drive-side fluid chamber, and a driven-side piston that is moved as the drive-side piston moves and the amount of hydraulic fluid in the driven-side fluid chamber increases or decreases via the fluid passage; a fluid passage volume adjustment mechanism that increases or decreases the volume of the fluid passage in accordance with an increase or decrease in the volume of the hydraulic fluid, The liquid passage volume adjustment mechanism includes: a volume adjusting piston provided in the liquid path; a volume adjustment ball screw mechanism having a volume adjustment ball screw to which the volume adjustment piston is attached, and which increases or decreases the volume of the hydraulic path by moving the volume adjustment piston together with the volume adjustment ball screw.

5. a drive-side ball screw mechanism having a drive-side ball screw to which the drive-side piston is attached, the drive-side ball screw mechanism being driven by the drive motor to move the drive-side piston together with the drive-side ball screw; 2. The hydraulic circuit control device according to claim 1, further comprising: a drive-side ball screw cooling passage provided inside the drive-side ball screw, through which a refrigerant for cooling the drive-side ball screw flows.

6. 2. The hydraulic circuit control device according to claim 1, wherein the hydraulic passage volume adjustment mechanism is configured to increase or decrease the volume of the hydraulic passage based on at least one of a state index value that directly indicates an increase or decrease in the volume of the hydraulic fluid and a state index value that indirectly indicates an increase or decrease in the volume of the hydraulic fluid.

7. a fixed portion to which a fixed mold is attached; a movable part to which a movable mold is attached; a hydraulic circuit control device provided on the movable portion to move the movable portion relative to the fixed portion, The hydraulic circuit control device includes: A drive motor; a drive-side cylinder having a drive-side fluid chamber and a drive-side piston moved by the drive motor; a driven-side cylinder having a driven-side fluid chamber, a fluid passage connecting the driven-side fluid chamber and the drive-side fluid chamber, and a driven-side piston that is moved as the drive-side piston moves and the amount of hydraulic fluid in the driven-side fluid chamber increases or decreases via the fluid passage; a fluid path volume adjustment mechanism that increases or decreases the volume of the fluid path in accordance with an increase or decrease in the volume of the hydraulic fluid, the fluid path includes a main fluid path portion through which the hydraulic fluid flows between the driven-side fluid chamber and the drive-side fluid chamber, and an adjustment fluid path portion connected to the main fluid path portion; A molding machine wherein the liquid path volume adjustment mechanism includes a volume adjustment motor that moves the inner wall surface of the adjustment liquid path section, and is configured to increase or decrease the volume of the adjustment liquid path section by moving the inner wall surface.

Images