Patent Description:
In an injection molding machine described in Japanese Unexamined Patent Application Publication No. <CIT>, a cooling fan is installed on an outer surface of a frame, to which a stator core of a servomotor for the injection molding machine is attached, via a fan cover. The cooling fan forcibly performs ventilation in a direction orthogonal to an axial direction of the motor from a cooling air inlet bored in the frame toward a cooling air outlet bored in the frame to cool the inside of the servo motor.

Japanese Patent Document <CIT>discloses an injection molding machine in which dust generating areas comprise a cover, wherein the interior of the covers communicates with an exhaust passage.

German Patent Application <CIT> discloses a drive unit for an injection molding machine which is encased by a cover with a suction hole including a suction device.

Japanese Patent Document <CIT> discloses an apparatus for mounting and fixing a mold clamping device and an injection device on a machine base, which is divided into a mold clamping area, a mold area, and an injection area by a partition wall.

Japanese Patent Document <CIT> discloses an injection molding machine for injecting a molten resin using a linear motor, comprising a mold and a hollow portion communicating with the void of the mold, and receiving the resin raw material received in the hollow portion.

Japanese Patent Document <CIT> discloses an injection molding machine wherein a cooling fan cools a motor and air is exhausted from a housing to the outside via an exhaust fan.

An injection unit includes a drive source such as a motor and a mechanical element such as a ball screw which is operated by the drive source. If power is supplied to the drive source, Joule heat, frictional heat, or the like is generated in the drive source, and frictional heat or the like is generated in the mechanical element.

The injection unit includes a cover which surrounds the drive source and the mechanical element. Heat is easily collected inside the cover. Accordingly, an ambient temperature inside the cover easily increases, and a temperature of the drive source or a temperature of the mechanical element easily increases.

In a case where the cooling fan described in Japanese Unexamined Patent Application Publication No. <CIT> is installed inside the cover along with the drive source or the mechanical element, gas discharged from the cooling air outlet is returned to the cooling air inlet again. Accordingly, cooling effects cannot be sufficiently obtained.

The present invention is made in consideration of the above-described problems, and a main object thereof is to provide an injection unit capable of preventing a temperature of the drive source or the mechanical element surrounded by the cover from increasing.

Hereinafter, an embodiment of the present invention is described with reference to the drawings. However, in each drawing, the same or corresponding reference numerals are assigned to the same or corresponding configurations, and descriptions thereof are omitted.

<FIG> is a top view of an injection molding machine according to an embodiment. In <FIG>, in order to show the inside of a cover <NUM>, a ceiling portion 61a of the cover <NUM> shown in <FIG> or <FIG> is removed. However, a position of an exhaust fan <NUM> attached to the ceiling portion 61a is indicated by dashed lines. <FIG> is a sectional view of an injection unit taken along line II-II in <FIG>. <FIG> is a sectional view of the injection unit taken along line III-III in <FIG>.

As shown in <FIG>, the injection molding machine includes an injection unit <NUM> and a controller <NUM>. Hereinafter, a movement direction (a left direction in <FIG>) of a screw <NUM> during filling is defined as a front side and the movement direction (a right direction in <FIG>) of the screw <NUM> during plasticizing is defined as a rear side.

The injection unit <NUM> comes into contact with a mold unit (not shown), and fills the inside of the mold unit with a molding material. The molding material filling the inside of the mold unit is cooled and solidified, and thus, a molding product is obtained. For example, the injection unit <NUM> includes a cylinder <NUM>, a nozzle <NUM>, the screw <NUM> (refer to <FIG>), a cooler <NUM>, a plasticizing motor <NUM> (refer to <FIG>), an injection motor <NUM> (refer to <FIG>), a pressure detector <NUM> (refer to <FIG>), a heater <NUM>, and a temperature detector <NUM>.

The cylinder <NUM> heats the molding material which is supplied from a supply port 41a shown in <FIG> to the inside of the cylinder <NUM>. The supply port 41a is formed on the rear portion of the cylinder <NUM>. The cooler <NUM> such as a water cooling cylinder is provided on the outer periphery of the rear portion of the cylinder <NUM>. A heater <NUM> such as a band heater and the temperature detector <NUM> are provided on the outer periphery of the cylinder <NUM> on the front side of the cooler <NUM>.

The cylinder <NUM> is divided into a plurality of zones in an axial direction of the cylinder <NUM>. The heater <NUM> and the temperature detector <NUM> are provided in each zone. The controller <NUM> controls the heater <NUM> such that a detection temperature of the temperature detector <NUM> for each zone becomes a set temperature.

The nozzle <NUM> is provided on the front end portion of the cylinder <NUM> and presses the mold unit. The heater <NUM> and the temperature detector <NUM> are provided on the outer periphery of the nozzle <NUM>. The controller <NUM> controls the heater <NUM> such that a detection temperature of the nozzle <NUM> becomes a set temperature.

The screw <NUM> is disposed in the cylinder <NUM> so as to be rotatable and movable forward or backward. If the screw <NUM> rotates, the molding material is fed forward along spiral grooves of the screw <NUM>. The molding material is gradually melted by heat of the cylinder <NUM> while being fed forward. The liquid molding material is fed to the front portion of the screw <NUM> and is accumulated in the front portion of the cylinder <NUM>, and thus, the screw <NUM> moves backward. Thereafter, if the screw <NUM> moves forward, the molding material in front of the screw <NUM> is injected from the nozzle <NUM> and fills the inside of the mold unit.

The plasticizing motor <NUM> rotates the screw <NUM>.

The injection motor <NUM> moves the screw <NUM> forward or backward. The rotary motion of the injection motor <NUM> is converted into the linear motion of the screw <NUM> by the motion conversion mechanism <NUM>. As shown in <FIG>, the motion conversion mechanism <NUM> includes a screw shaft <NUM> and a screw nut <NUM> which is screwed to the screw shaft <NUM>. A ball or a roller may be interposed between the screw shaft <NUM> and the screw nut <NUM>.

The injection motor <NUM> and the motion conversion mechanism <NUM> are symmetrically disposed about the center line of the cylinder <NUM> or the screw <NUM> when viewed from above. In addition, each of the number of the injection motors <NUM> and the number of the motion conversion mechanisms <NUM> is not particularly limited, and, for example, may be one.

The pressure detector <NUM> is provided on a force transmission path between the injection motor <NUM> and the screw <NUM> and detects a load applied to the pressure detector <NUM>. The pressure detector <NUM> sends signals indicating the detection results to the controller <NUM>. The detection results of the pressure detector <NUM> are used to control or monitor a pressure received by the screw <NUM> from the molding material, a back pressure with respect to the screw <NUM>, a pressure applied from the screw <NUM> to the molding material, or the like.

The injection unit <NUM> performs a filling process, a holding pressure process, a plasticizing process, or the like under the control of the controller <NUM>.

In the filling process, the injection motor <NUM> is driven to move the screw <NUM> forward at a set speed, and the cavity space inside the mold unit is filled with the liquid molding material accumulated in front of the screw <NUM>. For example, a position or speed of the screw <NUM> is detected using an encoder of the injection motor <NUM>. The encoder of the injection motor <NUM> detects the rotation of the injection motor <NUM> and sends signals indicating the detection results to the controller <NUM>. If the position of the screw <NUM> reaches a set position, switching (so called V/P switching) from the filling process to the holding pressure process is performed. The set speed of the screw <NUM> maybe changed according to the position of the screw <NUM>, the time, or the like.

Moreover, in the filling process, after the position of the screw <NUM> reaches the set position, the screw <NUM> may temporarily stop at the set position, and thereafter, the V/P switching may be performed. Immediately before the V/P switching, instead of stopping the screw <NUM>, the screw <NUM> may move forward or may move backward at a very slow speed.

In the holding pressure process, the injection motor <NUM> is driven to press the screw <NUM> forward at a set pressure, and a pressure is applied to the molding material inside the mold unit. Accordingly, insufficient molding materials caused by cooling shrinkage can be replenished. For example, the pressure of the molding material is detected using the pressure detector <NUM>. The pressure detector <NUM> sends signals indicating the detection results to the controller <NUM>.

In the holding pressure process, the molding material inside the cavity space is gradually cooled, and when the holding pressure process is completed, the inlet of the cavity space is closed by the molding material which is solidified. This state is referred to as a gate seal, and a backflow of the molding material from the cavity space is prevented. After the holding pressure process, a cooling process starts. In the cooling process, solidification of the molding material inside the cavity space is performed. In order to shorten a molding cycle, the plasticizing process may be performed during the cooling process.

In the plasticizing process, the plasticizing motor <NUM> is driven to rotate the screw <NUM> at a set rotating speed and the molding material is fed forward along the spiral grooves of the screw <NUM> by the screw <NUM>. According to this, the molding material is gradually melted. The screw <NUM> moves backward as the liquid molding material is fed to the front side of the screw <NUM> and is accumulated in front of the cylinder <NUM>. For example, the rotating speed of the screw <NUM> is detected using an encoder of the plasticizing motor <NUM>. The encoder of the plasticizing motor <NUM> sends signals indicating the detection results to the controller <NUM>.

In the plasticizing process, in order to restrict an abrupt backward movement of the screw <NUM>, the injection motor <NUM> may be driven so as to apply a set back pressure to the screw <NUM>. For example, the back pressure with respect to the screw <NUM> is detected using the pressure detector <NUM>. The pressure detector <NUM> sends signals indicating the detection results to the controller <NUM>. If the screw <NUM> moves backward to the set position and a predetermined amount of the molding materials is accumulated in front of the screw <NUM>, the plasticizing process ends.

As shown in <FIG>, the controller <NUM> includes a Central Processing Unit (CPU) <NUM>, a recording medium <NUM> such as a memory, an input interface <NUM>, and an output interface <NUM>. The controller <NUM> executes a program stored in the recording medium <NUM> using the CPU <NUM> to perform various controls. In addition, the controller <NUM> receives signals from the outside using an input interface <NUM> and sends the signals to the outside using the output interface <NUM>.

Meanwhile, the injection unit <NUM> includes a cover <NUM> which surrounds the plasticizing motor <NUM>, the injection motor <NUM>, the motion conversion mechanism <NUM>, or the like in addition to the plasticizing motor <NUM>, the injection motor <NUM>, the motion conversion mechanism <NUM>, or the like. The cover <NUM> forms an accommodation chamber <NUM> which accommodates the plasticizing motor <NUM>, the injection motor <NUM>, the motion conversion mechanism <NUM>, or the like along with the base <NUM>. The cover <NUM> includes the ceiling portion 61a which forms an upper surface of the accommodation chamber <NUM> and a side wall portion 61b which forms a side surface of the accommodation chamber <NUM>. A gap SP shown in <FIG> is formed between the side wall portion 61b of the cover <NUM> and the base <NUM>.

A front support <NUM> which holds a rear end portion of the cylinder <NUM> and a rear support <NUM> which holds the injection motor <NUM> are fixed to the base <NUM>. A pressure plate <NUM> which holds the plasticizing motor <NUM> is provided so as to be movable forward or backward between the front support <NUM> and the rear support <NUM>.

The pressure plate <NUM> holds a bearing which rotatably supports an extension shaft of the screw <NUM>. The rotary motion of the plasticizing motor <NUM> is transmitted to the screw <NUM> by a rotation transmission mechanism <NUM> such as a belt, a pulley, or the like. Meanwhile, the rotary motion of the injection motor <NUM> is converted into the linear motion of the pressure plate <NUM> by the motion conversion mechanism <NUM> and is transmitted to the screw <NUM>.

As described above, the motion conversion mechanism <NUM> includes the screw shaft <NUM> and the screw nut <NUM> which is screwed to the screw shaft <NUM>. The screw shaft <NUM> is fixed to an output shaft of the injection motor <NUM>. Meanwhile, the screw nut <NUM> is fixed to the pressure plate <NUM>. The injection motor <NUM> is driven to rotate the screw shaft <NUM>. Accordingly, the screw nut <NUM> moves forward or backward and the screw <NUM> moves forward or backward along with the pressure plate <NUM>.

Here, the center line of the screw shaft <NUM> may coincide with the center line of the injection motor <NUM> as shown in <FIG> or <FIG>, or may be deviated from the center line of the injection motor <NUM>. In the latter case, a rotation transmission mechanism such as a belt or pulley is provided between the output shaft of the injection motor <NUM> and the screw shaft <NUM>. In this case, if the injection motor <NUM> is driven, the screw shaft <NUM> rotates to move the screw nut <NUM> forward or backward, and thus, the pressure plate <NUM> moves forward or backward.

In addition, the disposition of the screw shaft <NUM> and the screw nut <NUM> is not limited to the above-described disposition. In addition to the disposition, for example, as the disposition of the screw shaft <NUM> and the screw nut <NUM>, the disposition of the following (<NUM>) or the disposition of the following (<NUM>) may be adopted.

Here, the center line of the screw shaft <NUM> may coincide with the center line of the injection motor <NUM> or may be deviated from the center line of the injection motor <NUM>. In the latter case, a rotation transmission mechanism such as a belt or pulley is provided between the output shaft of the injection motor <NUM> and a rotation member deviated from the output shaft, and the extension shaft on the rear side of the screw shaft <NUM> is splined to the rotation member. In this case, if the injection motor <NUM> is driven, the screw shaft <NUM> moves forward or backward while rotating, and thus, the pressure plate <NUM> moves forward or backward.

(<NUM>) The extension shaft on the front side of the screw shaft <NUM> is fixed to the pressure plate <NUM>. Meanwhile, the screw nut <NUM> is fixed to the output shaft of the injection motor <NUM>. If the injection motor <NUM> is driven, the screw nut <NUM> moves the screw shaft <NUM> forward or backward while rotating, and thus, the pressure plate <NUM> moves forward or backward.

Here, the center line of the screw nut <NUM> may coincide with the center line of the injection motor <NUM> or may be deviated from the center line of the injection motor <NUM>. In the latter case, a rotation transmission mechanism such as a belt or pulley is provided between the output shaft of the injection motor <NUM> and the screw nut <NUM>. In this case, if the injection motor <NUM> is driven, the screw nut <NUM> rotates to move the screw shaft <NUM> forward or backward, and thus, the pressure plate <NUM> moves forward or backward.

Meanwhile, if the drive source such as the plasticizing motor <NUM> or the injection motor <NUM> is driven, Joule heat or friction heat is generated in the drive source. In addition, friction heat is generated in the mechanical element operated by the drive source, for example, in the rotation transmission mechanism <NUM>, the motion conversion mechanism <NUM>, or the like. The heat is generated inside the cover <NUM>.

Accordingly, the injection unit <NUM> of the present embodiment includes an exhaust fan <NUM> which discharges gas inside the cover <NUM> to the outside of the cover <NUM>. The heat generated inside the cover <NUM> can be discharged and the inside of the cover <NUM> can be cooled. Accordingly, it is possible to prevent the temperature of the drive source or the mechanical element from increasing. Therefore, it is possible to decrease a maintenance cost of the drive source or the mechanical element.

In order to discharge gas inside the cover <NUM> to the outside of the cover <NUM>, the exhaust fan <NUM> may suck the gas from the outside of the cover <NUM> to the inside thereof or may discharge the gas from the inside of the cover <NUM> to the outside thereof. In the latter case, a high-temperature gas inside the cover <NUM> is directly discharged. Accordingly, it is possible to effectively decrease the temperature inside the cover <NUM>.

The exhaust fan <NUM> is operated under the control of the controller <NUM>. Heating values or allowable temperatures per unit time of the drive source or the mechanical element are different from each other. Accordingly, the controller <NUM> may operate the exhaust fan <NUM> at all the time while a cycle operation of repeatedly manufacturing a molding product is performed. A rotating speed of the exhaust fan <NUM> maybe set so as to increase as the temperature inside the cover <NUM> increases. If a predetermined time elapses after the cycle operation ends, the controller <NUM> may stop the exhaust fan <NUM>.

The exhaust fan <NUM> is attached to the ceiling portion 61a of the cover <NUM>. In addition, the attachment position of the exhaust fan <NUM> is not particularly limited. For example, the exhaust fan <NUM> may be attached to the side wall portion 61b of the cover <NUM> or the like. In addition, the exhaust fan <NUM> may be attached to the base <NUM>.

For example, the exhaust fan <NUM> discharges the gas inside the cover <NUM> to the outside of the cover <NUM> via an opening portion of the cover <NUM>. The opening portion of the cover <NUM> becomes a discharge portion of the gas. An air pressure inside the cover <NUM> is decreased by the discharge of the gas, and air outside the cover <NUM> is introduced to the inside of the cover <NUM> by an air pressure difference. For example, the introduction portion may be the gap SP which is formed between the side wall portion 61b of the cover <NUM> and the base <NUM>.

In addition, the exhaust fan <NUM> may suck air outside the cover <NUM> to the inside of the cover <NUM> via an opening portion of the cover <NUM>. The opening portion of the cover <NUM> becomes the introduction portion of the air. The air pressure inside the cover <NUM> is increased by the introduction of the gas, and air inside the cover <NUM> is discharged to the outside of the cover <NUM> by the air pressure difference. For example, the discharge portion may be the gap SP which is formed between the side wall portion 61b of the cover <NUM> and the base <NUM>.

The introduction portion of the gas and the discharge portion of the gas may be positioned at positions facing each other. Moreover, each of the introduction portion of the gas and the discharge portion of the gas may be the opening portion formed on the base <NUM> in addition to the opening portion formed on the cover <NUM> or the gas SP formed between the side wall portion 61b of the cover <NUM> and the base <NUM>. The base <NUM> may be formed in a frame shape.

The number of the exhaust fans <NUM> is one in the drawing. However, a plurality of exhaust fans <NUM> may be provided. In this case, both the exhaust fan <NUM> which discharges the gas inside the cover <NUM> to the outside of the cover <NUM> and the exhaust fan <NUM> which sucks the gas outside the cover <NUM> to the inside of the cover <NUM> may be used.

The injection unit <NUM> includes motion conversion mechanism covers <NUM> which surround the motion conversion mechanisms <NUM> and motion conversion mechanism cooling fans <NUM> which cools the motion conversion mechanisms <NUM>. Each of the motion conversion mechanism cooling fans <NUM> discharges the gas inside the motion conversion mechanism cover <NUM> to the outside of the motion conversion mechanism cover <NUM>. Heat generated inside the motion conversion mechanism cover <NUM> can be discharged and the inside of the motion conversion mechanism cover <NUM> can be cooled. Accordingly, it is possible to prevent the temperature of the motion conversion mechanism <NUM> from increasing.

In order to discharge the gas inside the motion conversion mechanism cover <NUM> to the outside of the motion conversion mechanism cover <NUM>, the motion conversion mechanism cooling fan <NUM> may discharge the gas from the inside of the motion conversion mechanism cover <NUM> to the outside thereof or may suck the air from the outside of the motion conversion mechanism cover <NUM> to the inside thereof. In the latter case, air can come into direct contact with the motion conversion mechanism <NUM>, and thus, it is possible to effectively decrease the temperature of the motion conversion mechanism <NUM>.

The motion conversion mechanism cooling fan <NUM> is operated under the control of the controller <NUM>. For example, in a case where the temperature of the motion conversion mechanism <NUM> exceeds a set temperature, the controller <NUM> operates the motion conversion mechanism cooling fan <NUM>. The rotating speed of the motion conversion mechanism cooling fan <NUM> may be set so as to increase as the temperature of the motion conversion mechanism <NUM> increases. Meanwhile, in a case where the temperature of the motion conversion mechanism <NUM> is equal to or less than the set temperature, the controller <NUM> stops the motion conversion mechanism cooling fan <NUM>.

As the motion conversion mechanism cooling fan <NUM>, one of the fan which discharges gas inside the motion conversion mechanism cover <NUM> to the outside thereof and the fan which sucks gas outside the motion conversion mechanism cover <NUM> to the inside thereof is used or both thereof are used. An introduction portion of gas or a discharge portion of gas is provided in the motion conversion mechanism cover <NUM>. Heat radiation fins may be provided on the outer periphery of the motion conversion mechanism cover <NUM>.

The motion conversion mechanism cooling fans <NUM> are attached to the motion conversion mechanism cover <NUM>. The number of the motion conversion mechanism cooling fans <NUM> or the attachment position thereof is not particularly limited. In addition, the number of the motion conversion mechanism covers <NUM> or the attachment position thereof is not particularly limited.

Meanwhile, the motion conversion mechanism covers <NUM> and the motion conversion mechanism cooling fans <NUM> are surrounded by the cover <NUM>.

Moreover, the exhaust fan <NUM> discharges the gas discharged from the insides of the motion conversion mechanism covers <NUM> by the motion conversion mechanism cooling fans <NUM> to the outside of the cover <NUM>. Accordingly, it is possible to prevent the gas discharged from the inside of the motion conversion mechanism covers <NUM> from being returned to the insides of the motion conversion mechanism covers <NUM> again. Therefore, it is possible to effectively cool the insides of the motion conversion mechanism covers <NUM> and it is possible to shorten operation times of the motion conversion mechanism cooling fans <NUM>.

Each of the motion conversion mechanism covers <NUM> corresponds to a mechanical element cover described in claims and each of the motion conversion mechanism cooling fans <NUM> corresponds to a mechanical element cooling fan described in claims. In addition, the mechanical element surrounded by the mechanical element cover is not limited to the motion conversion mechanism <NUM>. For example, the mechanical element may be the rotation transmission mechanism <NUM> or the like and may be any one as long as it generates friction heat.

The injection unit <NUM> includes a plasticizing motor cover <NUM> which surrounds the plasticizing motor <NUM> and plasticizing motor cooling fans <NUM> which cool the plasticizing motor <NUM>. Each of the plasticizing motor cooling fans <NUM> discharges the gas inside the plasticizing motor cover <NUM> to the outside of the plasticizing motor cover <NUM>. Heat generated inside the plasticizing motor cover <NUM> can be discharged and the inside of the plasticizing motor cover <NUM> can be cooled. Accordingly, it is possible to prevent the temperature of the plasticizing motor <NUM> from increasing.

In order to discharge the gas inside the plasticizing motor cover <NUM> to the outside of the plasticizing motor cover <NUM>, the plasticizing motor cooling fan <NUM> may discharge the gas from the inside of the plasticizing motor cover <NUM> to the outside thereof or may suck the air from the outside of the plasticizing motor cover <NUM> to the inside thereof. In the latter case, air can come into direct contact with the plasticizing motor <NUM>, and thus, it is possible to effectively decrease the temperature of the plasticizing motor <NUM>.

The plasticizing motor cooling fan <NUM> is operated under the control of the controller <NUM>. For example, in a case where the temperature of the plasticizing motor <NUM> exceeds a set temperature, the controller <NUM> operates the plasticizing motor cooling fan <NUM>. The rotating speed of the plasticizing motor cooling fan <NUM> may be set so as to increase as the temperature of the plasticizing motor <NUM> increases. Meanwhile, in a case where the temperature of the plasticizing motor <NUM> is equal to or less than the set temperature, the controller <NUM> stops the plasticizing motor cooling fan <NUM>.

As the plasticizing motor cooling fan <NUM>, one of the fan which discharges gas inside the plasticizing motor cover <NUM> to the outside thereof and the fan which sucks gas outside the plasticizing motor cover <NUM> to the inside thereof is used or both thereof are used. An introduction portion of gas or a discharge portion of gas is provided in the plasticizing motor cover <NUM>. Heat radiation fins may be provided on the outer periphery of the plasticizing motor cover <NUM>.

The plasticizing motor cooling fans <NUM> are attached to the plasticizing motor cover <NUM>. The number of the plasticizingmotor cooling fans <NUM> or the attachment position thereof is not particularly limited.

Meanwhile, the plasticizing motor cover <NUM> and the plasticizing motor cooling fans <NUM> are surrounded by the cover <NUM>.

Moreover, the exhaust fan <NUM> discharges the gas discharged from the inside of the plasticizing motor cover <NUM> by the plasticizing motor cooling fans <NUM> to the outside of the cover <NUM>. Accordingly, it is possible to prevent the gas discharged from the inside of the plasticizing motor cover <NUM> from being returned to the inside of the plasticizing motor cover <NUM> again. Therefore, it is possible to effectively cool the insides of the plasticizing motor cover <NUM> and it is possible to shorten operation times of the plasticizing motor cooling fans <NUM>.

The plasticizing motor cover <NUM> corresponds to a drive source cover described in claims and the plasticizing motor cooling fan <NUM> corresponds to a drive source cooling fan described in claims. In addition, the drive source surrounded by the drive source cover is not limited to the plasticizing motor <NUM>. For example, the drive source may be the injection motor <NUM> or the like.

The injection unit <NUM> includes injection motor covers <NUM> which surround the injection motors <NUM> and injection motor cooling fans <NUM> which cool the injection motors <NUM>. Each of the injection motor cooling fans <NUM> discharges the gas inside the injection motor cover <NUM> to the outside of the injection motor cover <NUM>. Heat generated inside the injection motor cover <NUM> can be discharged and the inside of the injection motor cover <NUM> can be cooled. Accordingly, it is possible to prevent the temperature of the injection motor <NUM> from increasing.

In order to discharge the gas inside the injection motor cover <NUM> to the outside of the injection motor cover <NUM>, the injection motor cooling fan <NUM> may discharge the gas from the inside of the injection motor cover <NUM> to the outside thereof or may suck the air from the outside of the injection motor cover <NUM> to the inside thereof. In the latter case, air can come into direct contact with the injection motor <NUM>, and thus, it is possible to effectively decrease the temperature of the injection motor <NUM>.

The injection motor cooling fan <NUM> is operated under the control of the controller <NUM>. For example, in a case where the temperature of the injection motor <NUM> exceeds a set temperature, the controller <NUM> operates the injection motor cooling fan <NUM>. The rotating speed of the injection motor cooling fan <NUM> may be set so as to increase as the temperature of the injection motor <NUM> increases. Meanwhile, in a case where the temperature of the injection motor <NUM> is equal to or less than the set temperature, the controller <NUM> stops the injection motor cooling fan <NUM>.

As the injection motor cooling fan <NUM>, one of the fan which discharges gas inside the injection motor cover <NUM> to the outside thereof and the fan which sucks gas outside the injection motor cover <NUM> to the inside thereof is used or both thereof are used. An introduction portion of gas or a discharge portion of gas is provided in the injection motor cover <NUM>. Heat radiation fins may be provided on the outer periphery of the injection motor cover <NUM>.

The injection motor cooling fans <NUM> are attached to the injection motor covers <NUM>. The number of the injection motor cooling fans <NUM> or the attachment position thereof is not particularly limited.

Meanwhile, the injection motor covers <NUM> and the injection motor cooling fans <NUM> are surrounded by the cover <NUM>.

Moreover, the exhaust fan <NUM> discharges the gas discharged from the insides of the injection motor covers <NUM> by the injection motor cooling fans <NUM> to the outside of the cover <NUM>. Accordingly, it is possible to prevent the gas discharged from the insides of the injection motor covers <NUM> from being returned to the insides of the injection motor covers <NUM> again. Therefore, it is possible to effectively cool the insides of the injection motor covers <NUM> and it is possible to shorten operation times of the injection motor cooling fans <NUM>.

The injection motor cover <NUM> corresponds to a drive source cover described in claims and the injection motor cooling fan <NUM> corresponds to a drive source cooling fan described in claims.

As shown in <FIG>, the exhaust fan <NUM> may be disposed above the screw nut <NUM> when viewed in a direction perpendicular to a vertical direction and forward and backward directions. In a case where the screw nut <NUM> moves forward or backward, the exhaust fan <NUM> may be temporarily disposed above the screw nut <NUM>. The gas discharged from the motion conversion mechanism cover <NUM> surrounding the screw nut <NUM> can be effectively discharged to the outside of the cover <NUM>.

As shown in <FIG>, the exhaust fan <NUM> may be disposed on the screw nut <NUM> side of both sides of front and rear sides of the plasticizing motor <NUM> when viewed in the direction perpendicular to the vertical direction and the forward and backward directions. In a case where the plasticizing motor <NUM> or the screw nut <NUM> moves forward or backward, the exhaust fan <NUM> may be temporarily disposed on the screw nut <NUM> side of both sides of front and rear sides of the plasticizing motor <NUM>. The gas discharged from the motion conversion mechanism cover <NUM> surrounding the screw nut <NUM> can be effectively discharged to the outside of the cover <NUM> by the exhaust fan <NUM> while avoiding the plasticizing motor <NUM>.

As shown in <FIG>, in a case where the screw nut <NUM> is attached to the rear end surface of the pressure plate <NUM>, the exhaust fan <NUM> may be disposed on the rear side of the pressure plate <NUM> when viewed in the direction perpendicular to the vertical direction and the forward and backward directions. In a case where the pressure plate <NUM> moves forward or backward, the exhaust fan <NUM> may be temporarily disposed on the rear side of the pressure plate <NUM>.

In addition, the screw nut <NUM> may be attached to the front end surface of the pressure plate <NUM>. In this case, the exhaust fan <NUM> may be disposed on the front side of the pressure plate <NUM> when viewed in the direction perpendicular to the vertical direction and the forward and backward directions. In the case where the pressure plate <NUM> moves forward or backward, the exhaust fan <NUM> maybe temporarily disposed on the front side of the pressure plate <NUM>.

As shown in <FIG>, the exhaust fan <NUM> may be provided at the center between the pair of motion conversion mechanisms <NUM> when viewed from above. The gas discharged from the motion conversion mechanism covers <NUM> can be effectively discharged to the outside of the cover <NUM>.

In addition, the number of the motion conversion mechanisms <NUM> is not particularly limited. In a case where the number of the motion conversion mechanisms <NUM> is one, the exhaust fan <NUM> may overlap the motion conversion mechanism <NUM> when viewed from above.

As shown in <FIG>, the exhaust fan <NUM> may be provided above the center line of the cylinder <NUM> on the rear side of the cylinder <NUM>. The exhaust fan <NUM> may overlap the center line of the cylinder <NUM> when viewed from above. Since sources of heat such as the plasticizing motor <NUM>, the injection motor <NUM>, or the motion conversion mechanism <NUM> are collected around the center line of the cylinder <NUM>, discharging efficiency of heat is improved. In a case where the motion conversion mechanisms <NUM> are symmetrically disposed about the center line of the cylinder <NUM>, the exhaust fan <NUM> is provided between the pair of motion conversion mechanisms <NUM>.

In addition, the exhaust fan <NUM> may be provided above the center line of the cylinder <NUM> on the rear side of the plasticizing motor <NUM> provided behind the cylinder <NUM> and the front side of the injection motor <NUM>. Since there is almost no object blocking the flow of the gas on the rear side of the plasticizing motor <NUM> and the front side of the injection motor <NUM>, gas easily flows, and thus, discharging efficiency of heat is improved.

Hereinbefore, the embodiment of the injection unit is described. However, the present invention is not limited to the embodiment or the like, and various modifications and improvements can be applied within a scope of the present invention described in claims.

The injection unit <NUM> may include an air conditioner which is configured of an indoor unit provided in the accommodation chamber <NUM> formed of the cover <NUM> or the like and an outdoor unit provided outside the accommodation chamber <NUM>. The indoor unit and the outdoor unit are connected to each other by a refrigerant pipe, the indoor unit includes an evaporator which evaporates a refrigerant, and the outdoor unit includes a compressor which compresses the refrigerant to increase the temperature of the refrigerant, and a condenser which condenses the high-temperature refrigerant. The refrigerant receives heat generated in the accommodation chamber <NUM> and is evaporated, is carried to the outside, and is compressed so as to further increase the temperature. The high-temperature refrigerant is cooled by air so as to be condensed, and thereafter, is carried to the inside again.

In the above-described embodiment, the plasticizing motor <NUM> moves forward or backward along with the pressure plate <NUM>. However, the plasticizing motor <NUM> may be fixed to the front support <NUM>. In the latter case, the pressure plate <NUM> is not required. Moreover, in the latter case, the plasticizing motor <NUM> does not move forward or backward in order to move the screw <NUM> forward or backward. Accordingly, it is possible to increase acceleration when the forward movement of the screw <NUM> starts and it is possible to shorten the molding cycle.

In a case where the plasticizing motor <NUM> is fixed to the front support <NUM>, the plasticizing motor <NUM>, the plasticizing motor <NUM>, the injection motor <NUM>, and the screw <NUM> maybe coaxially provided. A bearing holder is splined to the output shaft of the plasticizing motor <NUM>. The bearing holder holds a bearing which rotatably supports the extension shaft on the front side of the screw shaft <NUM>. The extension shaft on the rear side of the screw shaft <NUM> is splined to the output shaft of the injection motor <NUM>. The screw nut <NUM> is fixed to the rear support <NUM>. The rotary motion of the injection motor <NUM> is converted into the rotary linear motion of the screw shaft <NUM>, is converted into the linear motion of the bearing holder, and thereafter, is transmitted to the screw <NUM>. The rotary motion of the plasticizing motor <NUM> is transmitted to the screw <NUM> via the bearing holder.

Claim 1:
An injection unit (<NUM>), comprising:
a drive source (<NUM>, <NUM>);
a mechanical element (<NUM>, <NUM>, <NUM>, <NUM>) which is operated by the drive source (<NUM>, <NUM>);
a cover (<NUM>) which surrounds the drive source (<NUM>, <NUM>) and the mechanical element (<NUM>, <NUM>, <NUM>, <NUM>); and
an exhaust fan (<NUM>) configured to discharge gas inside the cover (<NUM>) to the outside of the cover (<NUM>),
characterized by:
a mechanical element cover (<NUM>) which surrounds the mechanical element (<NUM>, <NUM>, <NUM>, <NUM>); and
a mechanical element cooling fan (<NUM>) configured to discharge gas inside the mechanical element cover (<NUM>) to the outside of the mechanical element cover (<NUM>),
wherein the cover (<NUM>) surrounds the drive source (<NUM>, <NUM>), the mechanical element (<NUM>, <NUM>, <NUM>, <NUM>), the mechanical element cover (<NUM>), and the mechanical element cooling fan (<NUM>), and
wherein the exhaust fan (<NUM>) discharges the gas discharged from the inside of the mechanical element cover (<NUM>) by the mechanical element cooling fan (<NUM>) to the outside of the cover (<NUM>).