JP7622601B2 - Valve Gate Unit - Google Patents

Description

The present invention relates to a valve gate unit.

Conventionally, a valve gate type hot runner mold apparatus is known as an apparatus for molding resin parts. This hot runner mold apparatus is used, for example, to manufacture resin parts for vehicles, and includes a valve gate unit that injects molten resin into a molding die, and a hot runner manifold that supplies molten resin to the valve gate unit. An example of this type of hot runner mold apparatus is disclosed in the following Patent Document 1.

The valve gate unit of this hot runner mold device is equipped with a heater built into the valve pin to heat the resin, and a temperature sensor built into the heater. This valve gate unit adjusts the current supplied to the heater based on the temperature measured by the temperature sensor, thereby controlling the temperature of the valve pin. This is intended to maintain good fluidity of the resin.

JP 2007-21502 A

However, with the above valve gate unit, there is concern that a phenomenon called "cold slug" may occur immediately after molding of the resin molded product begins. This cold slug is a phenomenon in which part of the resin is injected in an unmelted state due to a drop in temperature caused by heat dissipation from the molten resin, or resin that was once molten is injected in a cooled and solidified state. This phenomenon can be a factor that affects the quality of the resin molded product.

To address this issue, a structure in which the temperature of the heater itself is measured by a temperature sensor, as in the valve gate unit disclosed in Reference 1, is effective in controlling the temperature of the valve pin, but it is difficult to prevent the occurrence of cold slug because it is not possible to accurately measure the temperature of the heat dissipation part that is directly related to the occurrence of cold slug. Therefore, when designing this type of valve gate unit, there is a demand for technology that takes the occurrence of cold slug into consideration and aims to stabilize the quality of resin molded products.

The present invention was made in consideration of these problems, and aims to provide a valve gate unit that is effective in preventing deterioration of the quality of resin molded products.

One aspect of the present invention is
A valve gate unit that injects molten resin into a molding die,
a nozzle body having a resin flow path through which the molten resin flows and an injection gate which is an outlet of the resin flow path;
a valve pin provided in the resin flow path of the nozzle body and having a valve body portion at a tip of the pin for opening and closing the gate;
A temperature measuring sensor built into the nozzle body;
a heater for heating the molten resin flowing through the resin flow path;
a control unit that controls a heating output of the heater based on the temperature measured by the sensor;
Equipped with
the sensor is built in a valve seat portion of the nozzle body that comes into contact with the valve body portion when the gate is closed by the valve pin,
a sensor introduction hole is provided inside the nozzle body and extends from the outside of the nozzle body to the valve seat portion;
the sensor is installed in the valve seat through the sensor introduction hole of the nozzle body, and is electrically connected to a sensor connection wire extending from the control unit through the sensor introduction hole;
a valve gate unit, wherein the nozzle body has two half-split divided members which can be assembled to each other, each of the two divided members being provided with a hole-forming groove into which the sensor introduction hole is divided, and the sensor introduction hole is formed by the two hole-forming grooves when the two divided members are assembled ;
is located.

The valve gate unit of the above-mentioned aspect is used to inject molten resin into a molding die. In the nozzle body of this valve gate unit, the molten resin flows through a resin flow path toward a gate, which is the exit of the resin flow path. At this time, the gate is opened and closed by a valve body portion of a valve pin provided in the resin flow path of the nozzle body. When the valve body portion of the valve pin abuts against the valve seat portion of the nozzle body to close the gate, the molten resin temporarily stays in the resin flow path. In contrast, when the valve body portion of the valve pin moves away from the valve seat portion of the nozzle body to open the gate, the molten resin is injected from the gate into the molding die.

In this valve gate unit, the temperature is measured by a temperature sensor built into the valve seat of the nozzle body. The control unit then controls the heating output of the heater for heating the molten resin flowing through the resin flow path based on the temperature measured by the sensor. If a sensor is built into the valve seat of the nozzle body, the temperature of the heat dissipation area, which is directly related to the occurrence of cold slug, can be accurately measured. As a result, the occurrence of cold slug can be prevented, and the quality of the resin molded product can be stabilized.

As described above, the above-mentioned aspect provides a valve gate unit that is effective in preventing deterioration of the quality of resin molded products.

FIG. 1 is a perspective view partially showing a hot runner die apparatus according to a first embodiment. FIG. 2 is a side view of the valve gate unit according to the first embodiment. 3 is a cross-sectional view of the valve gate unit of FIG. 2 with the valve pin in a closed position. FIG. FIG. 3 is a cross-sectional view of the valve gate unit of FIG. 2 with the valve pin in an open position. FIG. 3 is a perspective view showing a divided structure of a tip portion of the nozzle body in FIG. 2 . FIG. 4 is an enlarged cross-sectional view showing a tip portion of the nozzle body in FIG. 3 . FIG. 5 is an enlarged cross-sectional view showing a tip portion of the nozzle body in FIG. 4 . FIG. 4 is a cross-sectional view of a valve gate unit according to a second embodiment, the cross-sectional view corresponding to FIG. 3 . FIG. 4 is a cross-sectional view of a valve gate unit according to a third embodiment, the cross-sectional view corresponding to FIG. 3 .

A preferred embodiment of the above aspect is described below.

In the valve gate unit of the above aspect, it is preferable that the heater is built into the valve body portion of the valve pin.

With this valve gate unit, a heater is built into the valve body of the valve pin, allowing heating to be performed at a position close to the valve seat, which has a built-in sensor for measuring temperature. This makes it possible to responsively heat the molten resin that is temporarily retained in the resin flow path when the gate is closed to the desired temperature quickly and easily using the heater based on the temperature measured by the sensor.

In the valve gate unit of the above aspect, a heater introduction hole is provided inside the valve pin, extending to the valve body portion, and the heater is preferably installed in the valve body portion through the heater introduction hole of the valve pin and electrically connected to a heater connection wiring extending from the control unit through the heater introduction hole.

With this valve gate unit, the heater can be installed in the valve body by utilizing the heater introduction hole provided inside the valve pin, and the heater connection wiring can be routed from the heater to the control unit. This simplifies the structure for installing the heater in the valve body of the valve pin.

In the valve gate unit of the above aspect, when the heater is the first heater, it is preferable to have a second heater provided separately from the first heater, and the second heater is configured to heat the outer surface of the nozzle body.

With this valve gate unit, the molten resin flowing through the resin flow path of the nozzle body can be heated by the first heater from the valve pin side of the resin flow path, and also by the second heater from the outer surface side of the nozzle body. Therefore, the molten resin flowing through the resin flow path of the nozzle body can be efficiently heated using both the first heater and the second heater.

In the valve gate unit of the above aspect, a sensor introduction hole is provided inside the nozzle body, extending from the outside of the nozzle body to the valve seat portion, and the sensor is preferably installed in the valve seat portion through the sensor introduction hole of the nozzle body and electrically connected to a sensor connection wiring extending from the control unit through the sensor introduction hole.

With this valve gate unit, the sensor can be installed in the valve seat using a sensor introduction hole provided inside the nozzle body, and the sensor connection wiring can be routed from the sensor to the control unit. This simplifies the structure for installing the sensor in the valve seat of the nozzle body.

In the valve gate unit of the above aspect, the nozzle body preferably has two split members in a half-split shape that can be assembled to each other, each of the two split members is provided with a hole-forming groove into which the sensor introduction hole is divided, and is configured such that the sensor introduction hole is formed by the two hole-forming grooves when the two split members are assembled.

With this valve gate unit, by providing hole configuration grooves into which the sensor introduction hole is divided in each of the two half-split divided members, the accuracy of the shape and installation position of the sensor introduction hole can be improved compared to when the sensor introduction hole is formed by drilling.

The following describes an embodiment of the valve gate unit with reference to the drawings.

In the drawings used to explain this embodiment, unless otherwise specified, the first direction, which is the axial direction of the valve gate unit, is indicated by arrow X, the second direction perpendicular to the first direction is indicated by arrow Y, and the third direction perpendicular to both the first and second directions is indicated by arrow Z.

(Embodiment 1)
As shown in Fig. 1, a hot runner mold apparatus (hereinafter simply referred to as "mold apparatus") 100 according to the first embodiment is a valve gate type hot runner mold apparatus. This mold apparatus 100 includes a plurality of valve gate units 1 that inject molten resin R into a molding mold (see "molding mold M" in Fig. 2), and a hot runner manifold 101 that supplies molten resin R to each valve gate unit 1.

This mold device 100 is for a multi-point gate having multiple valve gate units 1, and is therefore suitable for molding large plastic molded products such as bumpers for vehicle parts, for example. The number of valve gate units 1 connected to the hot runner manifold 101 is not particularly limited, and can be changed as needed.

As shown in FIG. 2, the valve gate unit 1 includes a nozzle body 10, a resin supply unit 20, a drive unit 30, a valve pin 40, sensors 50, 51, and 52 for measuring temperature, and heaters 60, 61, and 62 for heating.

(Structure of Nozzle Body 10)
2, the nozzle body 10 is connected to a resin supply section 20 having a resin flow path 21 through which the molten resin R in a molten state flows. The nozzle body 10 is a cylindrical member having a cylindrical shape, and is configured by connecting a body main section 11 and a tip section 12 to each other. The nozzle body 10 has a resin flow path 13 through which the molten resin R flows, and an injection gate 14 which is the outlet of the resin flow path 13. The nozzle body 10 is preferably configured from a metal material such as stainless steel.

The body main body 11 is a cylindrical member provided on the resin supply unit 20 side of the nozzle body 10. The tip tip 12 is a cylindrical member provided on the nozzle body 10 on the opposite side of the resin supply unit 20 across the body main body 11. A circular gate 14 is opened and formed on the end surface opposite the body main body 11 of both end surfaces of the tip tip 12 in the first direction X. In addition, the wall portion forming the gate 14 of the tip tip 12 is configured as a valve seat portion 15 provided corresponding to the valve body portion 42 of the valve pin 40. In other words, the gate 14 and the valve seat portion 15 are provided on the tip tip 12 of the body main body 11.

When the body main body 11 and the tip tip 12 are connected, the cylinder space of the body main body 11 and the cylinder space of the tip tip 12 are connected to each other, forming a resin flow path 13 through which the molten resin R flows. This resin flow path 13 is connected to the resin flow path 21 of the resin supply unit 20. Therefore, the molten resin R that flows from the resin flow path 21 of the resin supply unit 20 into the resin flow path 13 of the body main body 11 flows toward the gate 14.

(Structure of valve pin 40)
2, the valve pin 40 is a cylindrical member provided in the resin flow path 13 of the nozzle body 10. The valve pin 40 extends with its axial direction being the first direction X, and has a valve body portion 42 that opens and closes the gate 14 at one end, i.e., a pin tip portion 41a. The valve pin 40 has the other end, i.e., a pin rear end portion 41b, fixed to the end portion 31a of the rod 31 of the drive portion 30. The valve pin 40 is preferably made of the same type of metal material as the nozzle body 10.

The drive unit 30 is a known piston cylinder type actuator, and has the function of reciprocating the rod 31 in the first direction X. Therefore, the valve pin 40 is configured to be able to reciprocate in the first direction X in accordance with the movement of the rod 31. When the valve pin 40 is positioned, for example, with the pin tip 41a facing downward, when it descends downward in the first direction X to be positioned at the closed position P1, the valve body 42 abuts against the valve seat 15 to close the gate 14. In contrast, when the valve pin 40 rises upward from the closed position P1 in the first direction X, the valve body 42 moves away from the valve seat 15 to open the gate 14.

Sensors 50, 51, and 52 are all configured as sensors using thermocouples made of two types of conductors. Thermocouples are well known, and detailed explanations of their structure will be omitted, but they are configured to generate a voltage proportional to the temperature difference at the tip where the two types of conductors are joined. By detecting this voltage, the temperature at the location where the thermocouple is installed can be obtained. Using a thermocouple that has a simple structure and is inexpensive is effective in keeping device costs low.

As shown in FIG. 2, the sensor 50 is built into the nozzle body 10, particularly into the valve seat portion 15 of the tip portion 12. The valve seat portion 15 is the tip portion of the tip portion 12 in the first direction X. The sensor 51 is built into the retracted portion 16 of the tip portion 12. The retracted portion 16 is a position retracted from the valve seat portion 15 toward the main body portion 11 in the first direction X, and is a position radially outward from the valve seat portion 15. The sensor 52 is built into an annular member provided to circumferentially surround the outer surface 11a of the main body portion 11.

The heaters 60, 61, and 62 are all intended to indirectly heat the molten resin R flowing through the resin flow path 13 of the nozzle body 10.

As shown in FIG. 2, the heater 60 is a heater built into the valve body 42 of the valve pin 40. The heater 60 is configured to locally heat the valve body 42 of the valve pin 40 from the inside. The heater 60 has a known structure, and a detailed explanation of its structure will be omitted, but it is configured by housing an electric resistance heating type heating wire inside a cylindrical case that has electrical insulation. The heat transferred from the heater 60 to the valve pin 40 is transferred to the molten resin R flowing through the resin flow path 13, which is the external space of the valve body 42 of the valve pin 40, and is used to heat the molten resin R.

The heater 61 is a cylindrical heater that is provided to cover the outer surface 12a of the tip portion 12 in accordance with its cylindrical shape. The entire first zone on the tip side of the nozzle body 10, which corresponds to the tip portion 12, is heated by this heater 61. As a result, the heat transferred from the heater 61 to the tip portion 12 is transferred to the molten resin R flowing through the resin flow path 13, which is the cylindrical space inside the tip portion 12, and is used to heat the molten resin R.

Similarly, the heater 62 is a cylindrical heater that is provided to cover the outer surface 11a of the main body portion 11 in accordance with its cylindrical shape. The entire second zone on the rear end side of the nozzle body 10, which corresponds to the main body portion 11, is heated by this heater 62. As a result, the heat transferred from the heater 62 to the main body portion 11 is transferred to the molten resin R flowing through the resin flow path 13, which is the cylindrical space inside the main body portion 11, and is used to heat the molten resin R.

When the heater 60 built into the valve pin 40 is considered to be the first heater, the heaters 61 and 62 are second heaters provided separately from the first heater, and are configured to heat a part of the outer surface 10a of the nozzle body 10 from the outside. These heaters 61 and 62 are generally called "band heaters" and have the advantage that they can be easily attached to the nozzle body 10.

The molten resin R flowing through the resin flow path 13 of the nozzle body 10 can be heated by the first heater, heater 60, from the valve pin 40 side provided in this resin flow path 13, and can also be heated by the second heaters, heaters 61 and 62, from the outer surface side of the nozzle body 10. Therefore, the molten resin R flowing through the resin flow path 13 of the nozzle body 10 can be efficiently heated using both the first heater and the second heater.

As shown in Figures 3 and 4, the valve gate unit 1 is provided with a control unit 70. The control unit 70 is electrically connected to the drive unit 30, the sensors 50, 51, and 52, and the heaters 60, 61, and 62.

The control unit 70 outputs a control signal to the drive unit 30. This controls the valve pin 40 to either a closed position P1 (see FIG. 3) in which the valve body 42 abuts against the valve seat 15 of the nozzle body 10 to close the gate 14, or an open position P2 (see FIG. 4) in which the valve body 42 moves away from the valve seat 15 of the nozzle body 10 to open the gate 14.

The voltage generated by each thermocouple of sensors 50, 51, and 52 is detected as temperature information by control unit 70. Control unit 70 is configured to adjust the current supplied to heaters 60 and 61 based on the temperatures measured by sensors 50 and 51 to control the heating output of heaters 60 and 61. Control unit 70 is also configured to adjust the current supplied to heater 62 based on the temperature measured by sensor 52 to control the heating output of heater 62.

As shown in Figures 3 and 4, inside the tip portion 12 of the nozzle body 10, there is a sensor introduction hole 17 that extends from the outside of the tip portion 12 to the valve seat portion 15, and a sensor introduction hole 18 that extends from the outside of the tip portion 12 to the retracted portion 16.

The sensor 50 is installed in the valve seat portion 15 through the sensor introduction hole 17, and is electrically connected to the sensor connection wiring 50a that extends from the control unit 70 through the sensor introduction hole 17. This allows the sensor 50 to be installed in the valve seat portion 15 using the sensor introduction hole 17 provided inside the tip portion 12 of the nozzle body 10, and the sensor connection wiring 50a to be routed from the sensor 50 to the control unit 70. This simplifies the structure for installing the sensor 50 in the valve seat portion 15 of the tip portion 12.

The sensor 51 is installed in the retracted portion 16 through the sensor introduction hole 18, and is electrically connected to the sensor connection wiring 51a that extends from the control unit 70 through the sensor introduction hole 18. This allows the sensor 51 to be installed in the retracted portion 16 using the sensor introduction hole 18 provided inside the tip portion 12 of the nozzle body 10, and the sensor connection wiring 51a to be routed from the sensor 51 to the control unit 70. This simplifies the structure for installing the sensor 51 in the retracted portion 16 of the tip portion 12.

As shown in Figures 3 and 4, a heater introduction hole 43 is provided inside the valve pin 40, extending to the valve body portion 42. The heater 60 is installed in the valve body portion 42 through this heater introduction hole 43, and is electrically connected to a heater connection wiring 60a that extends from the control unit 70 through the heater introduction hole 43. This makes it possible to use the heater introduction hole 43 provided inside the valve pin 40 to install the heater 60 in the valve body portion 42, and to route the heater connection wiring 60a from the heater 60 to the control unit 70. This simplifies the structure for installing the heater 60 in the valve body portion 42 of the valve pin 40.

As shown in FIG. 5, the tip portion 12 of the nozzle body 10 preferably has two split members 12A, 12B that can be assembled together. Each of the two split members 12A, 12B has a hole-forming groove for when the sensor introduction hole 17 is divided into two, and a hole-forming groove for when the sensor introduction hole 18 is divided into two.

Regarding the division structure of the tip tip portion 12, specifically, a hole-forming groove 17a forming a part of the sensor introduction hole 17 and a hole-forming groove 18a forming a part of the sensor introduction hole 18 are formed on the joint end surface of one divided member 12A. The hole-forming groove 17a extends from the outside of the tip tip portion 12 to the valve seat portion 15, and the hole-forming groove 18a extends from the outside of the tip tip portion 12 to the retreat portion 16. In contrast, a hole-forming groove 17b forming the remainder of the sensor introduction hole 17 and a hole-forming groove 18b forming the remainder of the sensor introduction hole 18 are formed on the joint end surface of the other divided member 12B. The hole-forming groove 17b extends from the outside of the tip tip portion 12 to the valve seat portion 15, and the hole-forming groove 18b extends from the outside of the tip tip portion 12 to the retreat portion 16.

For this reason, the tip tip portion 12 is configured such that when the two divided members 12A, 12B are assembled, the joining end faces are brought together, so that the sensor introduction hole 17 is formed by the two hole-forming grooves 17a, 17b, and the sensor introduction hole 18 is formed by the two hole-forming grooves 18a, 18b.

By providing hole-forming grooves 17a, 17b into which the sensor introduction hole 17 is divided in each of the two divided members 12A, 12B, the accuracy of the shape and installation position of the sensor introduction hole 17 can be improved compared to when the sensor introduction hole 17 is formed by drilling. Similarly, by providing hole-forming grooves 18a, 18b into which the sensor introduction hole 18 is divided in each of the two divided members 12A, 12B, the accuracy of the shape and installation position of the sensor introduction hole 18 can be improved compared to when the sensor introduction hole 18 is formed by drilling.

Next, the temperature control at the tip portion 12 of the nozzle body 10 will be explained with reference to Figures 6 and 7.

As shown in FIG. 6, when the valve pin 40 is in the closed position P1, the flow of molten resin R in the resin flow path 13 of the tip portion 12 of the nozzle body 10 temporarily stops. As a result, the molten resin R temporarily stagnates in the resin flow path 13. At this time, the valve seat portion 15 of the tip portion 12 and the valve body portion 42 of the valve pin 40 are both in a high temperature state compared to the molding die M, so heat is dissipated by heat transfer from the molding die M, which is relatively low temperature. Therefore, the molten resin R stagnates in the resin flow path 13 is likely to be at its coldest in the proximity region 13a closest to the valve seat portion 15 and the valve body portion 42.

If part of the molten resin R accumulates in this vicinity region 13a in an unmelted or cooled, solidified state, a phenomenon known as "cold slug" may occur in which part of the resin is injected in a solidified state toward the molding die M immediately after the start of molding of the resin molded product. This phenomenon may cause the solidified resin to flow onto the design surface of the resin molded product, which may result in a deterioration in the quality of the resin molded product.

In this embodiment, in order to accurately measure the temperature of the heat dissipation area in the tip portion 12 that is directly related to the occurrence of cold slugs, a sensor 50 is built into the valve seat portion 15 of the tip portion 12 of the nozzle body 10. The valve seat portion 15 is in contact with the proximity region 13a of the resin flow path 13 and corresponds to the heat dissipation area. For this reason, the sensor 50 built into the valve seat portion 15 is particularly effective in accurately measuring the temperature of the heat dissipation area in the tip portion 12. As a result, it becomes possible to accurately determine whether the molten resin R retained in the proximity region 13a is at a temperature at which it will solidify.

In addition, in this embodiment, by incorporating a heater 60 in the valve body 42 of the valve pin 40, heating can be performed at a position close to the valve seat 15, which incorporates a sensor 50 for measuring temperature. Because the valve body 42 is in contact with the proximity region 13a of the resin flow path 13, the molten resin R that temporarily remains in this proximity region 13a when the gate is closed can be responsively heated to the desired temperature quickly by the heater 60 based on the temperature measured by the sensor 50.

For example, when the sensor 50 detects that the temperature of the valve seat portion 15 has dropped below the threshold at which the molten resin R solidifies in the adjacent region 13a, the control unit 70 controls the heating output of the heater 60 to raise the temperature of the valve body portion 42 of the valve pin 40 to a temperature equal to or higher than the threshold. This makes it possible to perform pinpoint temperature control specific to the heat dissipation portion of the tip portion 12.

By preventing the molten resin R from solidifying in the proximity region 13a, the molten resin R is injected into the molding die M through the gate 14 in an unsolidified state even when the set position of the valve pin 40 is switched from the closed position P1 to the open position P2 as shown in FIG. 7. This prevents the solidified resin from flowing onto the design surface of the resin molded product.

According to the above-mentioned embodiment 1, based on the above content, the following effects can be obtained.

The valve gate unit 1 of the first embodiment is used to inject molten resin R into a molding die M. At the tip 12 of the nozzle body 10 of this valve gate unit 1, the molten resin R flows through a resin flow path 13 toward a gate 14, which is the outlet of the resin flow path 13. At this time, the gate 14 is opened and closed by a valve body 42 of a valve pin 40 provided in the resin flow path 13. When the valve body 42 of the valve pin 40 abuts against the valve seat 15 to close the gate 14, the molten resin R temporarily stays in the resin flow path 13. On the other hand, when the valve body 42 of the valve pin 40 moves away from the valve seat 15 to open the gate 14, the molten resin R is injected from the gate 14 into the molding die M.

In this valve gate unit 1, the temperature is measured by a temperature measuring sensor 50 built into the valve seat portion 15. The control unit 70 then controls the heating output of the heater 60 for heating the molten resin R flowing through the resin flow path 13 based on the temperature measured by the sensor 50. Here, by building the sensor 50 into the valve seat portion 15, the temperature of the heat dissipation portion, which is directly related to the occurrence of cold slug, can be accurately measured. As a result, the occurrence of cold slug can be prevented, and the quality of the resin molded product can be stabilized.

Therefore, according to the first embodiment, it is possible to provide a valve gate unit 1 that is effective in preventing deterioration of the quality of resin molded products.

Below, other embodiments related to the above-mentioned embodiment 1 will be described with reference to the drawings. In the other embodiments, elements that are the same as those in embodiment 1 are given the same reference numerals, and descriptions of the same elements will be omitted.

(Embodiment 2)
As shown in FIG. 8, the valve gate unit 2 of the second embodiment differs from the valve gate unit 1 of the first embodiment in that the valve pin 40 is not provided with a heating means such as a heater 60 .
The other configurations are similar to those of the valve gate unit 1 of the first embodiment.

In the valve gate unit 2, the control unit 70 is configured to adjust the current supplied to the heater 61 based on the temperatures measured by the sensors 50 and 51, thereby controlling the heating output of the heater 61.

According to the valve gate unit 2 of the second embodiment, the structure of the valve pin 40 can be simplified and the number of heaters can be reduced, compared to the valve gate unit 1 of the first embodiment.
In addition, the same effects as those of the first embodiment are achieved.

(Embodiment 3)
9, the valve gate unit 3 of the third embodiment differs from the valve gate unit 1 of the first embodiment in that the sensor 51 is not provided. Therefore, the tip portion 12 of the nozzle body 10 is not provided with a portion corresponding to the sensor introduction hole 18.
The other configurations are similar to those of the valve gate unit 1 of the first embodiment.

In the valve gate unit 3, the control unit 70 is configured to adjust the current supplied to each of the heaters 60, 61 based on the temperature measured by the sensor 50, thereby controlling the heating output of each of the heaters 60, 61.

According to the valve gate unit 3 of the third embodiment, the structure of the tip portion 12 of the nozzle body 10 can be simplified and the number of sensors can be reduced, compared to the valve gate unit 1 of the first embodiment.
In addition, the same effects as those of the first embodiment are achieved.

The present invention is not limited to the above-described embodiment, and various applications and modifications are possible without departing from the purpose of the present invention. For example, the following forms can be implemented by applying the above-described embodiment.

In the above embodiment, the two divided members 12A, 12B constituting the tip portion 12 are assembled to form the sensor introduction hole 17 with the two hole forming grooves 17a, 17b, and the sensor introduction hole 18 with the two hole forming grooves 18a, 18b. Alternatively, at least one of the sensor introduction hole 17 and the sensor introduction hole 18 may be formed by drilling.

REFERENCE SIGNS LIST 1, 2, 3 Valve gate unit 10 Nozzle body 10a, 11a, 12a Outer surface of nozzle body 12A, 12B Divided member 13 Resin flow path 14 Gate 15 Valve seat portion 17 Sensor introduction hole 17a, 17b Hole forming groove 40 Valve pin 41a Pin tip portion 42 Valve body portion 43 Heater introduction hole 50 Sensor 50a Sensor connection wiring 60 Heater (first heater)
60a Heater connection wiring 61, 62 Second heater 70 Control unit M Molding die R Molten resin

Claims (4)

A valve gate unit that injects molten resin into a molding die,
a nozzle body having a resin flow path through which the molten resin flows and an injection gate which is an outlet of the resin flow path;
a valve pin provided in the resin flow path of the nozzle body and having a valve body portion at a tip of the pin for opening and closing the gate;
A temperature measuring sensor built into the nozzle body;
a heater for heating the molten resin flowing through the resin flow path;
a control unit that controls a heating output of the heater based on the temperature measured by the sensor;
Equipped with
the sensor is built in a valve seat portion of the nozzle body that comes into contact with the valve body portion when the gate is closed by the valve pin,
a sensor introduction hole is provided inside the nozzle body and extends from the outside of the nozzle body to the valve seat portion;
the sensor is installed in the valve seat through the sensor introduction hole of the nozzle body, and is electrically connected to a sensor connection wire extending from the control unit through the sensor introduction hole;
The nozzle body has two half-split divided members that can be assembled to each other, and each of the two divided members is provided with a hole-forming groove into which the sensor introduction hole is divided, and the sensor introduction hole is formed by the two hole-forming grooves when the two divided members are assembled. This valve gate unit is configured as follows . The valve gate unit according to claim 1, wherein the heater is built into the valve body of the valve pin. The valve gate unit according to claim 2, wherein the inside of the valve pin is provided with a heater introduction hole extending to the valve body portion, the heater is installed in the valve body portion through the heater introduction hole of the valve pin, and is electrically connected to a heater connection wiring extending from the control unit through the heater introduction hole. The valve gate unit according to claim 2 or 3, wherein when the heater is a first heater, a second heater is provided separately from the first heater, and the second heater is configured to heat the outer surface of the nozzle body.

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