JP7256459B2 - Injection mold equipment - Google Patents

Description

The present invention relates to an injection mold apparatus.

As shown in Patent Literature 1, an injection mold device for manufacturing a resin product having an internal thread includes a core pin that rotates around an axis by being driven by a gear mechanism. The core pin moves in the axial direction through rotation about the axis, and moves in and out of the cavity of the mold according to the movement in the axial direction. Also, the core pin has a threaded portion for forming an internal thread in the resin product.

In the injection mold apparatus, the core pin is advanced into the cavity of the clamped mold to reach one end of the movement in the axial direction, and in that state, the molten resin is injected into the cavity. do. After the injected resin has hardened, the core pin is rotated and moved in the direction opposite to the above in the axial direction, and through this movement the core pin is retracted from the cavity. A resin product having Note that the core pin retracted from the cavity reaches the other end of its axial movement.

JP-A-8-207104

By the way, if an attempt is made to shorten the product manufacturing cycle using an injection mold apparatus in order to increase product production efficiency, the moving speed of the core pin in the axial direction must be increased. As a result, the impact when the core pin reaches the end of its movement in the axial direction increases, which may lead to a decrease in the durability of the injection mold device.

SUMMARY OF THE INVENTION An object of the present invention is to provide an injection mold apparatus capable of suppressing deterioration in durability.

Means for solving the above problems and their effects will be described below.
An injection mold apparatus for solving the above problems includes a core pin that rotates around an axis through drive by a gear mechanism. This core pin has a threaded portion, and moves in the axial direction through rotation about the axis to advance or retract into the cavity of the clamped mold. In the above-described injection mold apparatus, molten resin is injected into the cavity of the clamped mold with the core pin advanced into the cavity, and after the resin has hardened, the core pin is rotated to move the core pin into the cavity. By retracting from the inside, a resin product having an internal thread formed by the threaded portion of the core pin is manufactured. Moreover, the above injection mold apparatus is provided with the following brake mechanism. That is, the brake mechanism is directly connected to the core pin, and reduces the speed of axial movement of the core pin when it reaches the end of its axial movement.

According to the above configuration, the braking mechanism reduces the moving speed of the core pin when it reaches the terminal end of its axial movement, so that the impact when the core pin reaches the terminal end is reduced. Therefore, it is possible to prevent the impact from increasing when the core pin reaches the terminal end of the movement in the axial direction, and the deterioration of the durability of the injection molding die device that accompanies it. Moreover, since the moving speed of the core pin in the axial direction can be directly reduced by the brake mechanism directly connected to the core pin, the moving speed can be reduced more effectively.

Schematic diagram showing the overall configuration of an injection mold device. FIG. 4 is a schematic view showing a drive device provided in the injection mold device as viewed from above; Sectional drawing which shows the brake mechanism of an injection molding die apparatus. The top view which shows the state which looked at the same brake mechanism from upper direction.

An embodiment of an injection mold apparatus will be described below with reference to FIGS. 1 to 4. FIG.
The injection mold apparatus shown in FIG. 1 is for manufacturing a resin product 2 having an internal thread 1 such as a cylinder head cover of an internal combustion engine. The injection mold apparatus performs clamping and opening of the molds 3 and 4 by vertically moving the mold 4 toward and away from the fixed mold 3 . In the injection mold apparatus, molten resin is injected into the cavities 5 of the clamped molds 3 and 4, and the resin product 2 is formed by hardening the resin. After forming the resin product 2 , the molds 3 and 4 are opened and the resin product 2 is removed from the molds 3 and 4 .

A mold 4 is provided with a core pin 6 for forming the internal thread 1 of the resin product 2 . The core pin 6 extends in a direction toward and away from the mold 3 (vertical direction in FIG. 1), and extends through a through hole 8a of an adjustment block 8 provided in a fixed block 7 of the mold 4 in the vertical direction in FIG. passes through. A helical spline 6b that meshes with a helical spline 8b formed on the inner peripheral surface of the through hole 8a is formed on the outer peripheral surface of the portion of the core pin 6 that penetrates the through hole 8a of the adjusting block 8. As shown in FIG.

Therefore, when the core pin 6 is rotated about its axis L, the core pin 6 rotates in the direction in which the axis L extends according to the rotation direction at that time through the meshing of the helical spline 6b of the core pin 6 and the helical spline 8b of the adjustment block 8. move to Such movement of the core pin 6 in the direction in which the axis L extends advances or retracts the core pin 6 with respect to the cavities 5 of the clamped molds 3 and 4 . The adjustment block 8 is normally fixed to the fixed block 7, but when adjusting the position of the core pin 6 in the axial direction, the adjustment block 8 is released from the fixation and is centered on the axis L of the core pin 6. Relative movement in the rotational direction is possible.

A portion of the outer peripheral surface of the core pin 6 protruding toward the mold 3 from the adjustment block 8, more specifically, a threaded portion used to form the internal thread 1 in the resin product 2 is provided at the end in the advancing direction (lower side in FIG. 1). 6a is formed. When the core pin 6 advances into the cavity 5 of the clamped molds 3 and 4, the threaded portion 6a of the core pin 6 is positioned within the cavity 5. As shown in FIG. In this state, molten resin is injected into the cavity 5, and after the resin hardens, the core pin 6 is rotated and withdrawn from the cavity 5, that is, moved upward in FIG. The internal thread 1 is formed by the threaded portion 6a of the 6. As shown in FIG.

The mold 4 is provided with a gear mechanism 9 for driving the core pin 6 to rotate around its axis L, and a drive device 10 for driving the gear mechanism 9 . The gear mechanism 9 is housed in a housing portion 11 formed in the mold 4 . On the other hand, the end of the core pin 6 on the side opposite to the threaded portion 6a (upper side in FIG. 1) passes through a cover 12 for closing the upper portion of the housing portion 11 from below to above. The core pin 6 is rotatably supported around the axis L by the lid 12 and the adjustment block 8 .

A gear 13 is fixed to a portion of the core pin 6 between the lid 12 and the adjustment block 8 , and a brake mechanism 14 is provided to a portion above the lid 12 . The brake mechanism 14 is directly connected to the core pin 6, and when the core pin 6 reaches the end of its axial movement, the brake mechanism 14 brakes the core pin 6 against the cavity 5 of the clamped molds 3, 4. When the core pin 6 reaches the end of its movement in the advancing direction, the movement speed of the core pin 6 in the axial direction is reduced.

Next, the gear mechanism 9 and the driving device 10 will be described.
The gear mechanism 9 has a first rotating shaft 15 and a second rotating shaft 16 extending parallel to the core pin 6 . The first rotating shaft 15 and the second rotating shaft 16 are rotatably supported by the fixed block 7 and the lid body 12, respectively. Gears 17 and 18 are fixed to the first rotating shaft 15 . A gear 19 meshing with the gear 18 of the first rotating shaft 15 is fixed to the second rotating shaft 16 , and a gear 20 meshing with the gear 13 of the core pin 6 is fixed.

The driving device 10 includes a cylinder 21 that expands and contracts in the horizontal direction (direction perpendicular to the paper surface of FIG. 1), and the gear 17 of the first rotating shaft 15 in the gear mechanism 9 meshes with the cylinder 21 extending in the direction of expansion and contraction. and a rack 22 that moves horizontally by expansion and contraction of the cylinder 21 . The gear mechanism 9 is driven by horizontally moving the rack 22 through the expansion and contraction of the cylinder 21 in the driving device 10, and the core pin 6 is rotated about its axis by driving the gear mechanism 9. As shown in FIG. More specifically, when the rack 22 moves horizontally, the movement is converted into rotation of the first rotating shaft 15 by the gear 17, and the rotation of the first rotating shaft 15 is rotated by the gears 18 and 19 to rotate the second rotating shaft 16. is transmitted to Furthermore, the rotation of the second rotating shaft 16 is transmitted to the core pin 6 by the gears 20 and 13 . As a result, the core pin 6 rotates about its axis and moves in the axial direction along with the rotation.

Incidentally, in this example, the contraction of the cylinder 21 advances the core pin 6 into the cavity 5 (moves downward in FIG. 1), while the extension of the cylinder 21 causes the core pin 6 to retreat from the cavity 5 (moves upward in FIG. 1). do. Therefore, when the contraction of the cylinder 21 is maximized, the end of the movement of the core pin 6 in the direction in which the core pin 6 advances into the cavity 5 is reached. At this time, the end portion of the core pin 6 on the side of the threaded portion 6a contacts the mold 3 of the clamped molds 3 and 4 . Further, when the extension of the cylinder 21 is maximized, the movement of the core pin 6 in the direction in which the core pin 6 retreats from the cavity 5 reaches the end. At this time, the end of the core pin 6 on the side of the threaded portion 6a is retracted from the cavity 5. As shown in FIG.

In the gear mechanism 9, the fixing of the gears 17 and 18 to the first rotating shaft 15 and the fixing of the gears 19 and 20 to the second rotating shaft 16 can be released. Incidentally, the release of the fixed gears changes the relative positions of the gears 17 and 18 with respect to the first rotating shaft 15 in the rotating direction, and also changes the relative positions of the gears 19 and 20 with respect to the second rotating shaft 16 in the rotating direction. The change is performed when adjusting the position of the core pin 6 in the axial direction. The adjustment of the position of the core pin 6 in the axial direction is the position when the core pin 6 reaches the end of the movement in the direction in which the core pin 6 advances into the cavity 5 after maintenance of the injection mold device. is done about

After the maintenance of the injection mold device, the position when the core pin 6 reaches the end of its movement in the direction in which the core pin 6 advances into the cavity 5 is an appropriate position (the end of the core pin 6 on the threaded portion 6a side is There is a high possibility that it is displaced from the position where it abuts on the mold 3). Therefore, in the state where the contraction of the cylinder 21 in the driving device 10 is maximized, the position when the core pin 6 reaches the end of the above movement is changed relative to the rotation direction of the gears 17 and 18 with respect to the first rotation shaft 15. , and by changing the relative positions of the gears 19 and 20 in the direction of rotation with respect to the second rotary shaft 16 . After that, by appropriately changing the relative position of the adjustment block 8 with respect to the fixed block 7 of the mold 4 in the direction of rotation about the axis L of the core pin 6, the position of the core pin 6 when reaching the end of the above-mentioned movement can be properly adjusted. position.

FIG. 2 schematically shows the driving device 10 viewed from above. As can be seen from FIG. 2, the cylinder 21 of the drive 10 comprises a fixing member 23 to which the rack 22 is fixed. The fixing member 23 moves in the horizontal direction (horizontal direction in FIG. 2) together with the rack 22 when the cylinder 21 expands and contracts. A guide block 24 is fixed to the fixing member 23, and a guide bar 25 extending in the horizontal direction in FIG. 2 is inserted through the guide block 24. As shown in FIG. Both longitudinal ends of the guide bar 25 are supported by support blocks 26 and 27 fixed to the mold 4 (FIG. 1). Movement of the fixed member 23 and the rack 22 accompanying expansion and contraction of the cylinder 21 is guided by the guide block 24 and the guide bar 25 .

The driving device 10 is provided with extension side stoppers 28 and contraction side stoppers 29 so as to be positioned at both ends of the movement range of the fixed member 23 (rack 22) when the cylinder 21 is extended and retracted. The extension side stopper 28 has a rubber material 30 that contacts the fixed member 23 when the extension of the cylinder 21 is maximized.

The contraction-side stopper 29 consists of a buffer plate 32 connected to the fixed member 23 via a spring 31 with a predetermined clearance, and a stopper that contacts the buffer plate 32 when the contraction of the cylinder 21 reaches its maximum. a plate 33; When the fixing member 23 comes close to the buffer plate 32 against the elasticity of the spring 31 when the contraction of the cylinder 21 is maximized, the contraction side stopper 29 absorbs the impact of the contact. absorb by the elasticity of

Next, the brake mechanism 14 will be described.
As shown in FIG. 3, the brake mechanism 14 includes a first plate 35 fixed to the core pin 6 both axially and rotationally about the axis. In addition, the brake mechanism 14 is positioned closer to the cavity 5 (closer to the lower side in FIG. 3) than the first plate 35 in the axial direction of the core pin 6, and is movable relative to the core pin 6 in the axial direction. There is also a second plate 36 which is fixed with respect to rotation about the axis. The surface of the second plate 36 on the cavity 5 side (lower surface in FIG. 3) is positioned so that the lid body 12 of the mold 4 does not reach the end of the movement of the core pin 6 when moving in the direction of advancing into the cavity 5 . It is a contact surface 37 that comes into contact with the .

An elastic member 38 made of urethane rubber or the like is provided between the first plate 35 and the second plate 36 in the brake mechanism 14 . This elastic member 38 is fixed to the first plate 35 by bolts 39 . A rod-shaped guide member 40 extending in the same direction as the core pin 6 and passing through the first plate 35 is fixed to the second plate 36 .

The shaft portion 40b of the guide member 40 penetrating through the first plate 35 and the first plate 35 are relatively movable in the direction in which the core pin 6 extends (vertical direction in FIG. 3). The shaft portion 40b of the guide member 40 guides the relative movement of the first plate 35 and the second plate 36 in the approaching/separating direction. Further, in the guide member 40 , the head portion 40 a has a larger diameter than the shaft portion 40 b and is located on the opposite side of the first plate 35 to the second plate 36 . Accordingly, the head portion 40a of the guide member 40 prevents the first plate 35 and the second plate 36 from being largely separated from each other.

When the core pin 6 moves toward the cavity 5 and reaches the end of the movement, the elastic member 38 elastically changes from the state indicated by the two-dot chain line in FIG. is compressed (elastic deformation) to Due to the elasticity of the elastic member 38 compressed in this way, the moving speed of the core pin 6 in the axial direction when the core pin 6 reaches the end of the movement is reduced. Further, as described above, the elastic member 38 is elastically deformed so that the core pin 6 reaches the terminal end, that is, the end of the core pin 6 on the side of the threaded portion 6a (FIG. 1) abuts the die 3 .

FIG. 4 shows the brake mechanism 14 of FIG. 3 viewed from above. As can be seen from FIG. 4 , a plurality (three in this example) of the elastic members 38 and the bolts 39 are provided at equal intervals around the axis of the core pin 6 . Also, the guide members 40 are provided between the elastic members 38 around the axis of the core pin 6 . Therefore, the number of guide members 40 is equal to the number of elastic members 38 (three in this example).

Next, the operation of the injection mold apparatus according to this embodiment will be described.
When the cylinder 21 of the driving device 10 is contracted when the molds 3 and 4 are clamped, the movement of the fixing member 23 and the rack 22 accompanying this movement drives the gear mechanism 9 , and through the drive of the gear mechanism 9 the core pin 6 is moved. rotates about its axis. As the core pin 6 moves in the axial direction through the rotation of the core pin 6 at this time, the core pin 6 advances into the cavity 5 of the clamped molds 3 and 4 . Then, when the core pin 6 reaches the terminal end of the movement in the direction in which the core pin 6 advances into the cavity 5, the elastic member 38 of the brake mechanism 14 is elastically compressed before the arrival, thereby reducing the moving speed of the core pin 6. be done.

Molten resin is injected into the cavity 5 of the clamped molds 3 and 4 under the condition that the core pin 6 is positioned at the end of the above-mentioned movement in the advancing direction to the cavity 5 . After the resin hardens, the cylinder 21 is extended to move the fixed member 23 and the rack 22, thereby driving the gear mechanism 9. Through the driving of the gear mechanism 9, the core pin 6 rotates about its axis as described above. rotate in the opposite direction. As the core pin 6 moves in the axial direction through the rotation of the core pin 6 at this time, the core pin 6 retreats from the cavity 5 of the clamped molds 3 and 4 . Thus, the resin product 2 having the internal thread 1 is formed. After forming the resin product 2 , the molds 3 and 4 are opened and the resin product 2 is removed from the molds 3 and 4 .

The core pin 6 retracted from the cavity 5 as described above reaches the end of its movement in the retracting direction. By repeating the operation described above, the resin product 2 having the internal thread 1 is continuously manufactured. In order to increase the production efficiency when continuously manufacturing the resin products 2 having the internal threads 1, the speed of movement of the core pin 6 in the axial direction has to be increased in order to shorten the manufacturing cycle of the resin products 2 by the injection mold device. I have to. Even if the moving speed of the core pin 6 in the axial direction is increased in this way, the moving speed of the core pin 6 when reaching the end of the movement in the advancing direction with respect to the cavity 5 is reduced by the brake mechanism 14. is suppressed from increasing the impact when it reaches the end.

According to this embodiment detailed above, the following effects can be obtained.
(1) When the core pin 6 reaches the end of its axial movement toward the cavity 5, it is suppressed that the impact at the time of arrival is increased, in other words, the impact is reduced. will be Therefore, even if the movement speed of the core pin 6 in the axial direction is increased, the impact when the core pin 6 reaches the terminal end of the movement is increased, and the deterioration of the durability of the injection mold device associated therewith is suppressed. can.

(2) Since the brake mechanism 14 is directly connected to the core pin 6, the movement speed of the core pin 6 can be directly reduced by the brake mechanism 14, and the reduction can be performed more effectively. If the moving speed of the core pin 6 is reduced via the gear mechanism 9 or the like, the gear mechanism 9 or the like may adversely affect the effective reduction of the moving speed. can be suppressed.

(3) If the position of the core pin 6 reaching the end of the movement in the direction in which the core pin 6 advances into the cavity 5 is deviated from the proper position due to a large impact when the core pin 6 reaches the end of the movement, A problem arises in that the accuracy of the threaded portion 6a in the resin product 2 manufactured by the injection molding machine is lowered. As a countermeasure to this problem, it is conceivable to readjust the position every time the position of the core pin 6 that has reached the terminal end deviates from the proper position. Another problem arises that the production efficiency of the resin product 2 is lowered. However, the occurrence of the various problems described above is suppressed by reducing the impact when the core pin 6 reaches the terminal end.

(4) When the core pin 6 moves in the direction of advancing into the cavity 5 (the axial direction of the core pin 6), the contact surface 37 of the second plate 36 touches the mold 4 ( The second plate 36 comes into contact with the cover 12), thereby stopping the axial movement of the second plate 36, while the axial movement of the core pin 6 continues. As a result, the first plate 35 fixed to the core pin 6 approaches the second plate 36, and the elastic member 38 provided between the two is elastically compressed, so that the axial direction of the core pin 6 is reduced. movement speed will be properly reduced.

(5) In the brake mechanism 14, the elastic member 38 for reducing the moving speed of the core pin 6 in the direction (axial direction) in which the core pin 6 advances into the cavity 5 is provided with the first plate 35 and the second plate 36. , are provided at equal intervals around the axis of the core pin 6 . Therefore, when the core pin 6 moves such that the elastic member 38 between the first plate 35 and the second plate 36 is elastically compressed, that is, when the first plate 35 approaches the second plate 36, The first plate 35 becomes less inclined with respect to the second plate 36 .

(6) between the first plate 35 and the second plate 36 of the brake mechanism 14 and between each elastic member 38 around the axis of the core pin 6, the core pin 6 of the first plate 35 and the second plate 36 A guide member 40 is provided for guiding the relative movement in the axial direction of. These guide members 40 can guide the relative movement of the first plate 35 and the second plate 36 in the axial direction of the core pin 6 without tilting each other.

(7) When the extension of the cylinder 21 in the driving device 10 is maximized, the fixed member 23 of the cylinder 21 contacts the rubber member 30 of the extension side stopper 28, and the elasticity of the rubber member 30 causes the fixed member 23 to contact. of shock is absorbed. Therefore, the extension-side stopper 28 can reduce the collision noise when the cylinder 21 is fully extended.

(8) When the contraction of the cylinder 21 in the driving device 10 is maximized, the buffer plate 32 of the contraction side stopper 29, that is, the buffer plate 32 connected to the fixed member 23 of the cylinder 21 via the spring 31, is closed to the contraction side stopper. 29 is in contact with the stopper plate 33 . As a result, the fixed member 23 of the cylinder 21 approaches and contacts the buffer plate 32 against the elastic force of the spring 31 , and the impact of the contact is absorbed by the elasticity of the spring 31 . Therefore, the contraction-side stopper 29 can reduce the collision noise when the cylinder 21 is contracted to the maximum.

It should be noted that the above embodiment can be modified, for example, as follows. The above embodiments and the following modifications can be combined with each other within a technically consistent range.
- The extension-side stopper 28 and the contraction-side stopper 29 do not necessarily have to absorb impact.

- The elastic members 38 do not necessarily need to be provided at equal intervals around the axis of the core pin 6 .
- It is not always necessary to provide a plurality of elastic members 38 .

- It is not always necessary to provide a plurality of guide members 40 .
- The guide member 40 may be omitted.
・Instead of or in addition to the brake mechanism 14, the core pin 6 reaches the end of its movement in the retracting direction (upward in FIG. 1) with respect to the cavity 5 of the clamped molds 3 and 4. In this case, a brake mechanism may be provided to reduce the moving speed of the core pin 6 in the axial direction.

DESCRIPTION OF SYMBOLS 1... Female screw, 2... Resin product, 3... Mold, 4... Mold, 5... Cavity, 6... Core pin, 6a... Threaded part, 6b... Helical spline, 7... Fixed block, 8... Adjusting block, 8a... Penetration Hole 8b...Helical spline 9...Gear mechanism 10...Drive device 11...Accommodating part 12...Lid body 13...Gear 14...Brake mechanism 15...First rotating shaft 16...Second rotating shaft DESCRIPTION OF SYMBOLS 17... Gear 18... Gear 19... Gear 20... Gear 21... Cylinder 22... Rack 23... Fixed member 24... Guide block 25... Guide bar 26... Support block 27... Support block 28 Extension side stopper 29 Contraction side stopper 30 Rubber material 31 Spring 32 Buffer plate 33 Stopper plate 35 First plate 36 Second plate 37 Contact surface 38 Elasticity Member, 39... bolt, 40... guide member, 40a... head, 40b... shaft.

Claims (5)

It has a core pin that rotates around its axis through drive by a gear mechanism,
The core pin has a threaded portion, and moves in the axial direction through rotation about the axis to advance or retreat into the cavity of the clamped mold,
By injecting molten resin into the cavity of the clamped mold with the core pin advanced into the cavity, and after the resin is cured, the core pin is rotated and retracted from the cavity, In an injection mold device for manufacturing a resin product having an internal thread formed by the threaded portion of the core pin,
a brake mechanism that is directly connected to the core pin and reduces the speed of movement of the core pin in the axial direction when the core pin reaches the end of its axial movement ;
The brake mechanism reduces the moving speed of the core pin in the axial direction when the core pin reaches the end of the movement in the advancing direction into the cavity of the clamped mold,
The brake mechanism includes a first plate fixed to the core pin in both the axial direction and the rotational direction about the axis, a first plate movable relative to the core pin in the axial direction and the rotational direction about the axis. comprises a fixed second plate and a resilient member interposed between the first and second plates;
The second plate is positioned closer to the cavity than the first plate in the axial direction of the core pin, and reaches the end of movement when the core pin moves in the direction of advancing into the cavity. 1. An injection molding device, characterized in that it has a contact surface that contacts said mold before molding . 2. The injection mold apparatus according to claim 1 , wherein a plurality of said elastic members are provided at equal intervals around the axis of said core pin between said first plate and said second plate. In the injection mold device according to claim 1 or 2 ,
A cylinder that expands and contracts to drive the gear mechanism, an extension-side stopper that comes into contact with the cylinder to absorb impact when the extension of the cylinder reaches its maximum, and a cylinder when the contraction of the cylinder reaches its maximum. and a contraction-side stopper that contacts and absorbs impact. It has a core pin that rotates around its axis through drive by a gear mechanism,
The core pin has a threaded portion, and moves in the axial direction through rotation about the axis to advance or retreat into the cavity of the clamped mold,
By injecting molten resin into the cavity of the clamped mold with the core pin advanced into the cavity, and after the resin is cured, the core pin is rotated and retracted from the cavity, In an injection mold device for manufacturing a resin product having an internal thread formed by the threaded portion of the core pin,
a brake mechanism that is directly connected to the core pin and reduces the speed of movement of the core pin in the axial direction when the core pin reaches the end of its axial movement ;
A cylinder that expands and contracts to drive the gear mechanism, an extension-side stopper that comes into contact with the cylinder to absorb impact when the extension of the cylinder reaches its maximum, and a cylinder when the contraction of the cylinder reaches its maximum. and a contraction-side stopper that contacts and absorbs impact . 4. The brake mechanism reduces the speed of movement of the core pin in the axial direction when the core pin reaches the end of the movement in the advancing direction into the cavity of the clamped mold. The injection mold apparatus according to .

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