Mold clamping device

Abstract

To provide mold clamping device capable of properly cooling the ball screw shaft.SOLUTION: In a mold clamping device, a tailstock has a main body supporting one end of a pair of guide bars and one end of a ball screw shaft, a pair of overhangs protruding tangentially from both ends of the main body in the width direction, and a pair of supports provided at the ends of the pair of overhangs to support the other end of each pair of guide bars. A fan is installed at a position that is vertically displaced from the guide bar and facing a through opening that penetrates the overhang, to supply cooling air to the internal space surrounded by the main body, the pair of overhangs, and the crosshead.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a mold clamping device that clamps a mold. [Background technology]

[0002] Conventionally, there has been known a clamping device that opens and closes a fixed mold and a movable mold and clamps the molds by moving a movable die plate that supports a movable mold toward and away from a fixed die plate that supports the fixed mold (see, for example, Patent Document 1).

[0003] The clamping device described in Patent Document 1 includes a tailstock, a pair of guide bars and a ball screw shaft supported by the tailstock, an advance / retract nut screwed onto the ball screw shaft, and a crosshead that advances and retreats together with the advance / retract nut by the rotation of the ball screw shaft. Grease is applied to the ball screw shaft to lubricate the space between the ball screw shaft and the advance / retract nut. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-037065 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the clamping device described in Patent Document 1, a ball screw shaft is disposed in an internal space sandwiched between a tailstock, a crosshead, and a pair of guide bars. Therefore, there is a problem that heat generated when the clamping device is driven is trapped in the internal space, accelerating the deterioration of the grease applied to the ball screw shaft and reducing the durability of the ball screw shaft.

[0006] The present invention has been made to solve such problems in the conventional technology, and an object of the present invention is to provide a mold clamping device capable of appropriately cooling a ball screw shaft. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the present invention provides a mold clamping device which opens / closes a fixed mold and a movable mold and clamps the molds by moving a movable die plate which supports a movable mold toward and away from a fixed die plate which supports a fixed mold in a moving direction, the mold clamping device comprising: a tailstock; a pair of guide bars which are supported by the tailstock at positions spaced apart in a width direction of the mold clamping device perpendicular to the moving direction and each extend in the moving direction; a ball screw shaft which is rotatably supported by the tailstock between the pair of guide bars and extends in the moving direction; an advance / retract nut which is screwed onto the ball screw shaft; and a ball screw which is attached to the advance / retract nut which advances and retreats in the moving direction by rotation of the ball screw shaft and moves along the pair of guide bars. and a toggle link mechanism that moves the movable die plate in the approaching and separating direction in conjunction with the advancement and retreat of the crosshead, wherein the tailstock comprises a main body supporting one end of the pair of guide bars and one end of the ball screw shaft, a pair of protrusions protruding in the approaching and separating direction from both ends of the main body in the width direction, and a pair of support parts provided at tips of the pair of protrusions and supporting the other ends of the pair of guide bars, and further comprises a fan attached at a position shifted in the vertical direction from the guide bar and facing a through hole penetrating the protrusions, and supplying cooling air to an internal space surrounded by the main body, the pair of protrusions, and the crosshead. Effect of the Invention

[0008] According to the present invention, it is possible to obtain a mold clamping device capable of appropriately cooling a ball screw shaft. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a side view of an injection molding machine according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view of the main parts of the mold clamping device, omitting the crosshead and the fan. [Diagram 3]FIG. 2 is a perspective view of a main part of a mold clamping device to which a crosshead and a fan are attached. [Figure 4] FIG. [Diagram 5] FIG. 2 is a view of the mold clamping device as seen from the movable die plate side. [Figure 6] FIG. 2 is a hardware block diagram of the injection molding machine. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An injection molding machine 10 according to the present invention will be described below with reference to the drawings. The injection molding machine 10 is a device that injects a measured amount of molding material into a mold to form an injection molded product (hereinafter referred to as "injection molding"). However, a specific example of the molding machine is not limited to the injection molding machine 10, and may be an electric die-casting machine that injects molten metal (molding material) into a mold to form a molded product.

[0011] [Configuration of injection molding machine 10] Fig. 1 is a side view of an injection molding machine 10 according to this embodiment. As shown in Fig. 1, the injection molding machine 10 mainly includes a clamping unit 20, an injection unit 30, and a control unit 60 (see Fig. 6). The injection molding machine 10 also includes a base 11 member that supports the clamping unit 20 and the injection unit 30 at positions spaced apart in the left-right direction.

[0012] The clamping device 20 opens, closes, and clamps the mold 21. Specifically, the clamping device 20 mainly includes a fixed die plate 23 that supports a fixed-side mold 22, and a movable die plate 25 that supports a movable-side mold 24. The fixed-side mold 22 and the movable-side mold 24 are supported so as to face each other in the left-right direction (horizontal direction) of the injection molding machine 10.

[0013] The movable die plate 25 moves in the left-right direction by transmitting the driving force of a die opening / closing motor 49 (see FIG. 6). When the movable die plate 25 moves in the left direction, the fixed die 22 and the movable die 24 move away from each other. On the other hand, when the movable die plate 25 moves in the right direction, the fixed die 22 and the movable die 24 come into contact with each other, and a cavity (internal space) is formed inside the die 21. Then, when pressure is further applied in a direction that moves the movable die plate 25 in the right direction, the fixed die 22 and the movable die 24 are clamped. Details of the die clamping device 20 will be described later with reference to FIGS. 2 to 5.

[0014] The injection device 30 plasticizes, measures, and injects the molding material. The injection device 30 according to this embodiment is disposed apart from the mold clamping device 20 in the horizontal direction (to the right of the mold clamping device 20). The injection device 30 mainly includes a heating cylinder 31, a screw 32, a hopper 33, and a hopper block 34.

[0015] The heating cylinder 31 is a cylindrical member extending in the left-right direction of the injection molding machine 10. The heating cylinder 31 mainly includes a resin passage 35 and a nozzle 36. In addition, a band heater for heating the heating cylinder 31 is attached to the outer circumferential surface of the heating cylinder 31.

[0016] The resin passage 35 is a cylindrical space extending in the axial direction (longitudinal direction) inside the heating cylinder 31. The resin passage 35 communicates with the outside of the heating cylinder 31 (the cavity of the mold 21) through a nozzle 36 provided at the tip (front end) of the heating cylinder 31. In other words, the resin passage 35 is a space extending from the nozzle 36 along the axial direction.

[0017] The screw 32 is a cylindrical member. A spiral groove is formed on the outer circumferential surface of the screw 32. The screw 32 is accommodated in the internal space of the heating cylinder 31 in a state in which the screw 32 can move in the left-right direction of the injection molding machine 10 (hereinafter, referred to as "advance and retreat") and can rotate. The screw 32 advances and retreats when a driving force of an injection motor 37 is transmitted thereto, and rotates when a driving force of a metering motor 38 is transmitted thereto.

[0018] More specifically, when the injection motor 37 is rotated in the forward direction, the screw 32 moves (forward) toward the tip of the heating cylinder 31 (i.e., the nozzle 36). On the other hand, when the injection motor 37 is rotated in the reverse direction, the screw 32 moves (rearward) toward the base end of the heating cylinder 31 (i.e., the side opposite the nozzle 36). Hereinafter, within the range that the tip position of the screw 32 can reach within the heating cylinder 31, the position closest to the nozzle 36 is referred to as the "forward limit," and the position farthest from the nozzle 36 is referred to as the "rear limit." In addition, the terms "forward rotation" and "reverse rotation" of the injection motor 37 do not specify an absolute direction of rotation, but merely specify a relative relationship (i.e., forward rotation and reverse rotation are rotations in opposite directions).

[0019] The hopper 33 is a funnel-shaped member that stores the raw molding material. The hopper block 34 is a member that supports the heating cylinder 31 and the hopper 33. The hopper 33 communicates with a resin passage 35 through the hopper block 34 at a portion of the heating cylinder 31 closer to the base end than the tip end. The molding material stored in the hopper 33 is supplied to the resin passage 35 of the heating cylinder 31 through an opening provided at the lower end. The molding material used in this injection molding machine 10 is, for example, so-called "pellets" that are formed into a cylindrical shape.

[0020] In the injection device 30, the screw 32 moves backward while rotating by rotating the injection motor 37 in the reverse direction and rotating the metering motor 38. As a result, the pellets supplied through the hopper 33 are filled (metered) into the resin passage 35 ahead of the screw 32 while being plasticized. In addition, in the injection device 30, the injection motor 37 rotates forward to move the screw 32 forward. As a result, the plasticized resin ahead of the screw 32 is injected into the cavity of the mold 21 through the nozzle 36.

[0021] Fig. 2 is a perspective view of the main parts of the mold clamping device 20, omitting the crosshead 44 and the fans 48a to 48d. Fig. 3 is a perspective view of the main parts of the mold clamping device 20 to which the crosshead 44 and the fans 48a to 48d are attached. Fig. 4 is a side view of the tailstock 40. Fig. 5 is a view of the mold clamping device 20 as seen from the movable die plate 25 side.

[0022] In this embodiment, the direction in which the movable die plate 25 approaches and separates from the fixed die plate 23 coincides with the left-right direction in Fig. 1. The width direction of the mold clamping device 20 (injection molding machine 10), which is perpendicular to the approaching and separating direction, coincides with the front-rear direction (direction perpendicular to the paper surface) in Fig. 1. In other words, the approaching and separating direction and the width direction are each perpendicular to the up-down direction (i.e., horizontal directions), and are also perpendicular to each other on a horizontal plane. However, the relationship between the approaching and separating direction and the width direction and the left-right direction and the front-rear direction is relative, and is not limited to the above example.

[0023] As shown in Figures 2 to 5, the mold clamping device 20 includes a tailstock 40, a pair of guide bars 41a, 41b, a pair of ball screw shafts 42a, 42b, a pair of advance / retract nuts 43a, 43b, a crosshead 44, a toggle link mechanism 45, tie bars 46a, 46b, 46c, 46d, brackets 47a, 47b, and fans 48a, 48b, 48c, 48d.

[0024] The tailstock 40 is supported (fixed) on the upper surface of the base member 11 at the left end of the base member 11 (the position farthest from the injection unit 30). The tailstock 40 directly or indirectly supports components of the mold clamping unit 20. The tailstock 40 is configured to be movable in the left-right direction on the base member 11 depending on the thicknesses of the fixed mold 22 and the movable mold 24. The tailstock 40 further includes a main body 50, a pair of overhanging portions 51a, 51b, and a pair of supporting portions 52a, 52b.

[0025] The main body 50 is the leftmost part of the tailstock 40. The main body 50 is a rectangular part extending in the up-down and front-rear directions. The main body 50 supports the guide bars 41a, 41b, the ball screw shafts 42a, 42b, and one end (left end) of each of the tie bars 46a to 46d.

[0026] The overhanging parts 51a, 51b are provided at both ends in the width direction of the main body 50. The overhanging parts 51a, 51b overhang to the right (toward the movable die plate 25) from both ends in the width direction of the main body 50. The overhanging parts 51a, 51b are generally trapezoidal in shape. That is, the overhanging parts 51a, 51b have a shorter vertical height as they move away from the main body 50. Furthermore, the overhanging parts 51a, 51b are formed with through holes 53a, 53b.

[0027] The through holes 53a, 53b penetrate the protruding parts 51a, 51b in the thickness direction. The through holes 53a, 53b extend in the vertical direction across the installation positions of the guide bars 41a, 41b and the ball screw shafts 42a, 42b. That is, the upper ends of the through holes 53a, 53b are located above the guide bars 41a, 41b and the ball screw shafts 42a, 42b. The lower ends of the through holes 53a, 53b are located below the guide bars 41a, 41b and the ball screw shafts 42a, 42b.

[0028] Support portions 52a and 52b are provided at the tips of overhanging portions 51a and 51b (i.e., at positions spaced apart from main body 50 in the approaching and separating direction). Support portions 52a and 52b support the other ends (right ends) of guide bars 41a and 41b.

[0029] The guide bars 41a, 41b have one end supported by the main body 50 and the other end supported by the supports 52a, 52b. The guide bars 41a, 41b extend in the approaching and separating direction (left and right direction). The guide bars 41a, 41b are disposed at positions spaced apart in the width direction of the mold clamping unit 20. The guide bars 41a, 41b serve to guide the movement of the crosshead 44 in the approaching and separating direction.

[0030] The ball screw shafts 42a, 42b are rotatably supported at one end (left end) by the main body 50 of the tailstock 40. The ball screw shafts 42a, 42b are extended in the approaching and separating direction. The ball screw shafts 42a, 42b are disposed between (inside) the guide bars 41a, 41b. That is, the guide bars 41a, 41b and the ball screw shafts 42a, 42b are disposed in parallel to each other at the same position in the vertical direction. The ball screw shafts 42a, 42b are disposed apart from each other in the width direction of the mold clamping device 20. However, the mold clamping device 20 may include one ball screw shaft 42 disposed in the center of the width direction of the mold clamping device 20 and extended in the approaching and separating direction.

[0031] A male screw is formed on the outer circumferential surface of the ball screw shaft 42a, 42b, and extends helically in the extension direction. The advance / retract nuts 43a, 43b are screwed onto the ball screw shaft 42a, 42b. When the driving force of the mold opening / closing motor 49 is transmitted to rotate the ball screw shaft 42a, 42b, the advance / retract nuts 43a, 43b advance / retract in the approach / separation direction along the ball screw shaft 42a, 42b.

[0032] The crosshead 44 is disposed at a position closer to the movable die plate 25 than the main body 50 in the approaching / separating direction. The crosshead 44 is disposed between the overhanging portions 51a, 51b in the width direction of the mold clamping device 20. The guide bars 41a, 41b are inserted into the crosshead 44. The crosshead 44 is attached to the advance / retract nuts 43a, 43b. The crosshead 44 advances and retreats in the approaching / separating direction along the guide bars 41a, 41b together with the advance / retract nuts 43a, 43b that advance and retreat with the rotation of the ball screw shafts 42a, 42b.

[0033] More specifically, when the ball screw shafts 42a, 42b rotate in the first direction, the crosshead 44 and the advancing / retracting nuts 43a, 43b move (advance) in a direction away from the main body 50. On the other hand, when the ball screw shafts 42a, 42b rotate in the second direction, the crosshead 44 and the advancing / retracting nuts 43a, 43b move (retreat) in a direction approaching the main body 50. Note that the first direction and the second direction are opposite directions.

[0034] The toggle link mechanism 45 is connected to the movable die plate 25 and the crosshead 44. The toggle link mechanism 45 transmits the movement of the crosshead 44 to the movable die plate 25. That is, the toggle link mechanism 45 moves the movable die plate 25 closer to or farther from the fixed die plate 23 in conjunction with the forward and backward movement of the crosshead 44. More specifically, the toggle link mechanism 45 moves the movable die plate 25 closer to the fixed die plate 23 (i.e., mold closing and mold clamping) in conjunction with the forward movement of the crosshead 44. Also, the toggle link mechanism 45 moves the movable die plate 25 farther from the fixed die plate 23 (i.e., mold opening) in conjunction with the backward movement of the crosshead 44. The configuration of the toggle link mechanism 45 is already known, so a detailed description thereof will be omitted.

[0035] The tie bars 46a to 46d are arranged at positions spaced apart in the up-down and front-rear directions. The tie bars 46a to 46d extend in the approaching and separating directions. One end of each of the tie bars 46a to 46d is supported by the body 50 of the tailstock 40, passes through the movable die plate 25, and is supported by the fixed die plate 23 at the other end. The tie bars 46a to 46d guide the movable die plate 25 which approaches and separates from the fixed die plate 23.

[0036] Here, the mold clamping unit 20 has the tailstock 40 and an internal space 54 surrounded by the tailstock 40. More specifically, the internal space 54 is a space surrounded by the main body 50 and the protruding parts 51a and 51b of the tailstock 40, the crosshead 44, and the tie bars 46a to 46d. Therefore, air tends to remain in the internal space 54. However, this internal space 54 does not need to be a completely sealed space, and a gap may be formed between the component itself or adjacent components, and the gap may be connected to the outside of the mold clamping unit 20.

[0037] At least a portion of the guide bars 41a, 41b, the ball screw shafts 42a, 42b, and the advance / retract nuts 43a, 43b are housed in this internal space 54. As the advance / retract nuts 43a, 43b screwed onto the ball screw shafts 42a, 42b advance / retract, heat is generated at the sliding contact portions between the ball screw shafts 42a, 42b and the advance / retract nuts 43a, 43b. As a result, the temperature of the internal space 54 rises, accelerating the deterioration of the grease applied to the surfaces of the ball screw shafts 42a, 42b, and reducing the durability of the ball screw shafts.

[0038] Therefore, fans 48a to 48d are attached to the overhanging portions 51a, 51b via brackets 47a, 47b. The brackets 47a, 47b are attached to the outer surfaces of the overhanging portions 51a, 51b at positions facing through-holes 53a, 53b provided in the overhanging portions 51a, 51b. The brackets 47a, 47b face the through-holes 53a, 53b and support the fans 48a to 48d at predetermined positions and angles.

[0039] Fans 48a to 48d are attached to positions facing through-holes 53a and 53b via brackets 47a and 47b. More specifically, fans 48a and 48b are attached to bracket 47a (i.e., protruding portion 51a) at a position facing through-hole 53a. Meanwhile, fans 48c and 48d are attached to bracket 47b (i.e., protruding portion 51b) at a position facing through-hole 53b.

[0040] Moreover, the fans 48a to 48d are disposed at positions vertically offset from the guide bars 41a, 41b and the ball screw shafts 42a, 42b. More specifically, the fans 48a, 48c are disposed at positions upwardly offset from the guide bars 41a, 41b and the ball screw shafts 42a, 42b. Meanwhile, the fans 48b, 48d are disposed at positions downwardly offset from the guide bars 41a, 41b and the ball screw shafts 42a, 42b.

[0041] All of the fans 48a-48d may supply cooling air to the internal space 54 through the through-holes 53a, 53b by transmitting the driving force of the fan motors 55a-55d (see FIG. 6). In this case, the fans 48a, 48b are preferably attached to the protruding portion 51a in a state inclined up and down with respect to the horizontal direction (front-to-back direction) so that the cooling air is directed to the ball screw shaft 42a. Similarly, the fans 48c, 48d are preferably attached to the protruding portion 51b in a state inclined up and down with respect to the horizontal direction (front-to-back direction) so that the cooling air is directed to the ball screw shaft 42b.

[0042] Alternatively, some of the fans 84a-84d may supply cooling air to the internal space 54 and the rest may exhaust air from the internal space 54 by transmitting the driving force of the fan motors 55a-55d. In this case, the fans supplying cooling air to the internal space 54 are preferably attached to the protruding parts 51a, 51b in a state inclined so that the cooling air is directed toward the ball screw shafts 42a, 42b. The fans exhausting air from the internal space 54 are preferably attached to the protruding parts 51a, 51b in a state inclined so that the air around the ball screw shafts 42a, 42b is exhausted. The combination of supply of cooling air and exhaust of air by the fans 48a-48d is not particularly limited, but the following combinations are possible, for example.

[0043] As one example, fans 48a, 48b provided on one overhanging portion 51a may supply cooling air to the internal space 54, and fans 48c, 48d provided on the other overhanging portion 51b may exhaust air from the internal space 54. As another example, fans 48a, 48c provided above the guide bars 41a, 41b may supply cooling air to the internal space 54, and fans 48b, 48d provided below the guide bars 41a, 41b may exhaust air from the internal space 54. As yet another example, fan 48a provided above the guide bars 41a, 41b of one protrusion 51a and fan 48d provided below the guide bars 41a, 41b of the other protrusion 51b may supply cooling air to the internal space 54, and fan 48b provided below the guide bars 41a, 41b of one protrusion 51a and fan 48c provided above the guide bars 41a, 41b of the other protrusion 51b may exhaust air from the internal space 54.

[0044] As another example, although not shown, the fans 48a to 48d may be attached to the protruding parts 51a, 51b in a state inclined to the left and right direction. More specifically, the fans 48a, 48d may be attached to the protruding parts 51a, 51b in a state inclined so as to direct cooling air toward the advancing and retracting nuts 43a, 43b when the fixed mold 22 and the movable mold 24 are clamped.

[0045] As yet another example, the fans 48a-48d may be rotatably attached to the protruding portions 51a, 51b so as to direct cooling air to the retractable nuts 43a, 43b which move in the approaching and separating directions. The fans 48a-48d may rotate in conjunction with the advancement and retreat of the retractable nuts 43a, 43b under the control of the control device 60, which will be described later, so that cooling air is always directed to the retractable nuts 43a, 43b.

[0046] [Configuration of control device 60] Fig. 6 is a hardware block diagram of the injection molding machine 10. As shown in Fig. 6, the control device 60 includes a CPU (Central Processing Unit) 61 which is a calculation means, a ROM (Read Only Memory) 62 which stores various programs, and a RAM (Random Access Memory) 63 which is a working area for the calculation means. The CPU 61 may read and execute the programs stored in the ROM 62 to realize each process described below.

[0047] However, the specific configuration of the control device 60 is not limited to this, and may be realized by hardware such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA).

[0048] The control device 60 controls the overall operation of the injection molding machine 10. More specifically, the control device 60 controls the injection motor 37, the metering motor 38, the mold opening / closing motor 49, and the fan motors 55a to 55d based on various signals output from a temperature sensor 64 and a display / input device 67.

[0049] The temperature sensor 64 detects the temperature of the internal space 54 (typically, the ambient temperature of the internal space 54) and outputs a temperature signal indicating the detected temperature to the control device 60. Alternatively, instead of detecting the ambient temperature of the internal space 54, the temperature sensor 64 may detect the surface temperature of the ball screw shafts 42a, 42b or the advance / retract nuts 43a, 43b.

[0050] The display input device 67 is a user interface that includes a display (display device) that displays various information to be notified to the operator, and buttons, switches, dials, and the like (input devices) that accept input operations by the operator. The display input device 67 may also include a touch panel superimposed on the display. The display input device 67 accepts input operations by the operator and outputs an input signal corresponding to the accepted input operation to the control device 60.

[0051] As an example, the control device 60 may control the rotation of the fan motors 55a-55d based on the temperature detected by the temperature sensor 64. That is, the control device 60 may rotate the fan motors 55a-55d when the temperature detected by the temperature sensor 64 is equal to or higher than a threshold value, and may stop the fan motors 55a-55d when the temperature detected by the temperature sensor 64 is lower than the threshold value. Furthermore, the control device 60 may increase the rotation speed of the fan motors 55a-55d (in other words, increase the amount of cooling air supplied) as the temperature detected by the temperature sensor 64 becomes higher.

[0052] As another example, the control device 60 may control the rotation of the fan motors 55a-55d in conjunction with the moving direction of the crosshead 44. That is, the control device 60 may drive the fan motors 55a-55d when the crosshead 44 moves (advances) in a direction away from the main body 50. On the other hand, the control device 60 may stop the fan motors 55a-55d when the crosshead 44 moves (retracts) in a direction toward the main body 50.

[0053] As yet another example, the control device 60 may switch between supplying cooling air and discharging air by the fans 48a-48d in accordance with an input operation by an operator via the display input device 67. That is, the control device 60 may receive an input operation to instruct each of the fans 48a-48d displayed on the display input device 67 to supply or discharge.

[0054] According to the above embodiment, for example, the following advantageous effects are achieved.

[0055] According to the above embodiment, the fans 48a-48d are disposed at positions vertically offset from the guide bars 41a, 41b, so that the cooling air supplied from the fans 48a-48d reaches the ball screw shafts 42a, 42b without being obstructed by the guide bars 41a, 41b. This allows the ball screw shafts 42a, 42b to be appropriately cooled.

[0056] This makes it possible to suppress deterioration of the grease applied to the ball screw shafts 42a, 42b. As a result, it is possible to prevent a decrease in the durability of the ball screw shafts 42a, 42b, and to reduce the frequency of lubricating the ball screw shafts 42a, 42b with grease. In addition, since the temperature rise of the ball screw shafts 42a, 42b is suppressed, the cycle time of the injection molding machine 10 can be shortened.

[0057] However, the number and layout of the fans 48a to 48d are not limited to the above example. As another example, a fan may be provided only on one of the protruding portions 51a, 51b. As another example, a fan may be provided only on one of a position shifted upward from the guide bars 41a, 41b and a position shifted downward from the guide bars 41a, 41b. As yet another example, a plurality of fans may be arranged in the approaching and separating direction.

[0058] Furthermore, according to the above embodiment, the fans 48a-48d are installed at an angle so that the cooling air is directed toward the ball screw shafts 42a-42b, thereby making it possible to cool the ball screw shafts 42a-42b more efficiently. In this case, it is preferable to use the fans 48a-48d capable of generating a cooling air with high directionality. On the other hand, when it is important to convect the air in the internal space 54, it is sufficient to use the fans 48a-48d capable of generating a cooling air with high diffusivity. In this case, it is not necessary to incline the fans 48a-48d toward the ball screw shafts 42a-42b.

[0059] According to the above embodiment, the fans 48a to 48d are installed at an angle so that the cooling air is directed toward the reciprocating nuts 43a and 43b, thereby efficiently cooling the sliding contact portions between the ball screw shafts 42a and 42b and the reciprocating nuts 43a and 43b. In addition, the position of the reciprocating nuts 43a and 43b when the fixed mold 22 and the movable mold 24 are clamped is the position where the reciprocating nuts 43a and 43b stop, so that the time during which the cooling air hits the nuts can be extended. Furthermore, the fans 48a to 48d are rotated in conjunction with the advancement and retreat of the reciprocating nuts 43a and 43b, so that the time during which the cooling air hits the nuts can be further extended.

[0060] Furthermore, according to the above embodiment, by having some of the multiple fans 48a to 48d supply cooling air and the rest exhaust air, it is possible to replace the air in the internal space 54. This makes it possible to suppress a decrease in cooling efficiency caused by warm air stagnation in the internal space 54.

[0061] Furthermore, when the crosshead 44 approaches the main body 50, the volume of the internal space 54 decreases, and the air in the internal space 54 is discharged from the internal space 54 through gaps between the components. Thus, as in the above embodiment, by stopping the fans 48a-48d when the crosshead 44 moves in a direction approaching the main body 50, it is possible to prevent the discharge of the heated air from being hindered. However, if the installation positions of the fans 48a-48d are separated from the gaps between the components that serve as the main air passages, driving the fans 48a-48d may promote air exchange.

[0062] Furthermore, the present invention exerts a particularly remarkable effect when applied to the mold clamping device 20 having a pair of ball screw shafts 42a, 42b. More specifically, in the mold clamping device 20 in which there is no space to install a fan in the internal space 54, the ball screw shafts 42a, 42b can be appropriately cooled. However, the present invention can also be applied to a mold clamping device having a single ball screw shaft. Moreover, the present invention can also be applied to a mold clamping device in which a fan is installed in the internal space 54.

[0063] The above-described embodiments are illustrative examples of the present invention, and are not intended to limit the scope of the present invention to these embodiments. Those skilled in the art can implement the present invention in various other forms without departing from the gist of the present invention. [Explanation of symbols]

[0064] 10... injection molding machine, 11... base member, 20... mold clamping device, 21... mold, 22... fixed side mold, 23... fixed die plate, 24... movable side mold, 25... movable die plate, 30... injection device, 31... heating cylinder, 32... screw, 33... hopper, 34... hopper block, 35... resin passage, 36... nozzle, 37... injection motor, 38... metering motor, 40... tailstock, 41... guide bar, 42... ball screw shaft, 43... advance / retract nut, 44... crosshead, 45... toggle link mechanism, 46... tie bar, 47... bracket, 48... fan, 49... mold opening / closing motor, 50... main body, 51... extension portion, 52... support portion, 53... through hole, 54... internal space, 55... fan motor, 60... control device, 61... CPU, 62... ROM, 64... temperature sensor, 67... display input device

Claims

1. A mold clamping device for opening / closing a fixed mold and a movable mold and clamping the fixed mold and the movable mold by moving a movable die plate, which supports a fixed mold, toward and away from a fixed die plate, which supports a movable mold, in a moving direction, the mold clamping device comprising: Tailstock and a pair of guide bars supported by the tailstock at positions spaced apart in a width direction of the mold clamping device perpendicular to the approaching and separating direction, the guide bars each extending in the approaching and separating direction; a ball screw shaft rotatably supported by the tailstock between the pair of guide bars and extending in the approaching and separating direction; An advance / retract nut screwed onto the ball screw shaft; a crosshead that is attached to the reciprocating nut that reciprocates in the approaching and separating direction by rotation of the ball screw shaft and that reciprocates in the approaching and separating direction along the pair of guide bars; a toggle link mechanism that moves the movable die plate in the approaching and separating directions in conjunction with the advancement and retreat of the crosshead, The tailstock is a main body supporting one end of the pair of guide bars and one end of the ball screw shaft; A pair of protruding portions protruding in the approaching and separating direction from both ends of the main body in the width direction; a pair of support portions provided at the tips of the pair of overhanging portions and supporting the other ends of the pair of guide bars, The clamping device further comprises a fan that is attached at a position offset in the vertical direction from the guide bar and facing a through hole that passes through the protrusion, and supplies cooling air to an internal space surrounded by the main body, the pair of protrusions, and the crosshead.

2. 2. The mold clamping device according to claim 1, wherein the fan is attached to the protruding portion in a tilted state so that cooling air is directed toward the ball screw shaft.

3. The mold clamping device according to claim 1, characterized in that the fan is attached to the protruding portion at an angle so that cooling air is directed toward the advance / retract nut when the fixed mold and the movable mold are clamped.

4. The mold clamping device according to claim 1 , wherein the fan is rotatably attached to the protruding portion so as to direct cooling air toward the nut moving forward and backward in the approaching and separating direction.

5. The fan is attached to each of the pair of overhanging portions, Some of the fans supply cooling air to the internal space, The mold clamping device according to claim 1 , wherein the remaining fan exhausts air from the interior space.

6. the fan is attached to the protruding portion at a position offset upward from the guide bar and at a position offset downward from the guide bar, Some of the fans supply cooling air to the internal space, The mold clamping device according to claim 1 , wherein the remaining fan exhausts air from the interior space.

7. The mold clamping device according to claim 1 , wherein the fan stops supplying cooling air to the internal space when the crosshead moves in a direction approaching the main body.

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