Patent Description:
In the related art, there has been known a discharge device(for example, see Patent Literature <NUM> below). The discharge device is used for applying a viscous material to a predetermined applying target (workpiece). Generally, the discharge device includes a cylinder which is filled with a viscous material, a plunger which moves back and forth in the cylinder, a ball screw (feed screw) which is connected to the plunger, and a motor which is connected to the ball screw through a power transmission mechanism such as a gear. In the discharge device described in Patent Literature <NUM>, when the viscous material is applied to the target, the power transmission mechanism is driven by the motor to integrally move the ball screw and the plunger back and forth.

In the above-mentioned discharge device, by advancing the plunger in the cylinder, the inside of the cylinder is pressurized to feed the viscous material into the nozzle and to discharge the viscous material from the nozzle. Further, in the above-mentioned discharge device, when the material is supplied into the cylinder, the viscous material is supplied from the supply source (for example, a liquid supply pump) while the plunger is retreated in the cylinder, whereby the viscous material is supplied into the cylinder.

Patent Literature <NUM>: <CIT>
<CIT> relates to a fluid delivery device. <CIT> relates to a pump.

In the above-mentioned discharge device, when the viscous material is supplied into the cylinder, it is necessary to interlock the retreat of the plunger with the operation of the supply source. Therefore, it is necessary to strictly synchronize the amount (filling amount per unit time) of the viscous material filled in the cylinder with the speed at which the plunger is retreated in the cylinder. The control of the operation of the plunger when the viscous material is supplying, is considerably complicated.

The present invention has been made in view of the above problems, and an object of the invention is to provide a discharge device capable of easily controlling an operation of a plunger at the time of supplying a viscous material to a cylinder and a liquid supply method capable of forming a desired overlap portion.

The invention is defined by independent claims <NUM> and <NUM>. Further embodiments of the invention are set forth in dependent claims <NUM>-<NUM> and <NUM>.

A discharge device according to an embodiment of the present invention is a discharge device which discharges a viscous material from a nozzle communicating with a cylinder by pressurizing the viscous material supplied to the cylinder. The discharge device includes: a supply valve which controls a supply of the viscous material to the cylinder; a plunger which applies a pressure to the viscous material supplied to the cylinder; a ball screw which is movable in a same direction as a back-and-forth direction of the plunger; and a motor which is connected to the ball screw through a power transmission mechanism. The plunger and the ball screw are not connected. The discharge device further includes a pressure sensor which is arranged in the cylinder and detects a pressure of the viscous material supplied into the cylinder. The discharge device is configured to correct the internal pressure of the cylinder by raising the ball screw with the supply valve being closed to drop the internal pressure of the cylinder to a desired value after the viscous material is supplied to the cylinder. The pressure sensor is configured to detect the internal pressure of the cylinder after correcting the internal pressure.

A liquid supply method according to the present invention is a liquid supply method for supplying a viscous material to a discharge device for discharging the viscous material. The discharge device includes a supply valve which controls a supply of the viscous material to the cylinder, a plunger which applies a pressure to the viscous material supplied to the cylinder, a ball screw which is movable in a same direction as a back-and-forth direction of the plunger, and a motor which is connected to the ball screw through a power transmission mechanism, and the plunger and the ball screw are not connected. The discharge device further includes a pressure sensor which is arranged in the cylinder and detects a pressure of the viscous material supplied into the cylinder. The liquid supply method includes: supplying the viscous material by opening the supply valve in a state where the ball screw moves in a direction apart from the plunger before the viscous material is supplied to the cylinder. The liquid supply method further includes correcting the internal pressure of the cylinder by raising the ball screw with the supply valve being closed to drop the internal pressure of the cylinder to a desired value after the viscous material is supplied to the cylinder. The internal pressure of the cylinder is monitored after correcting the internal pressure.

According to the above discharge device, the ball screw connected to the motor through the power transmission mechanism is not connected to the plunger. Then, when the viscous material is supplied into the cylinder, the plunger retreats in the cylinder due to the pressurization by the viscous material supplied into the cylinder. Therefore, the discharge device does not need to strictly synchronize the amount (filling amount per unit time) of the viscous material filled in the cylinder with the speed at which the plunger is retreated in the cylinder, and thus the operation control of the plunger is facilitated.

Further, according to the above-described liquid supply method, the plunger moves to a position in contact with the ball screw in accordance with the supply of the viscous material into the cylinder, and advances in the cylinder in linkage with the advance of the ball screw at the time of starting discharging the viscous material. Therefore, in the discharge device in which the plunger and the ball screw are not connected, the advance of the ball screw and the advance of the plunger can be appropriately synchronized when the discharge of the viscous material is started, and thus it is possible to form a desired overlap portion (the overlapping portion of the initial applying portion and the final applying portion of the viscous material).

Note that, in the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. In addition, the dimensional ratios in the drawings are exaggerated for convenience of description, and may be different from the actual ratios.

<FIG> are views for describing a discharge device <NUM> according to this embodiment and a discharge method of a viscous material M by the discharge device <NUM>. Incidentally, <FIG> illustrate a procedure of performing liquid supply or the like when the viscous material M is discharged after the initial liquid supply. <FIG> is a flowchart illustrating each step of the discharge method of the viscous material M according to the embodiment.

The discharge device <NUM> according to this embodiment is a device which discharges the viscous material M supplied to a cylinder <NUM> from a nozzle <NUM> and applies the discharged viscous material M to a predetermined applying target such as workpiece (see <FIG>). The viscous material M is not particularly limited, and examples thereof include high-viscosity viscous materials such as reactive silicone, urethane resin, and epoxy resin. Further, the applying target is not particularly limited, and examples thereof include the joint surfaces of various flanges and screws of transportation equipment and industrial equipment.

Referring to <FIG> for an overview, the discharge device <NUM> includes a control unit <NUM> which controls the operation of the discharge device <NUM>, a supply valve <NUM> which controls the supply of the viscous material M to the cylinder <NUM>, a plunger <NUM> which applies a pressure to the viscous material M supplied to the cylinder <NUM>, a ball screw <NUM> which is movable in the same direction as a back-and-forth direction of the plunger <NUM>, and a motor <NUM> which is connected to the ball screw <NUM> through a power transmission mechanism <NUM>.

In the discharge device <NUM>, when the plunger <NUM> is advanced (move downward in <FIG>,hereinafter, also referred to as "lowered") in the cylinder <NUM> in a state where the viscous material M is supplied into the cylinder <NUM>, the viscous material M is discharged through the nozzle <NUM> communicating with the cylinder <NUM>. The viscous material M discharged from the nozzle <NUM> is applied on the applying target (not illustrated).

The cylinder <NUM> can store the viscous material M in the internal space of the cylinder <NUM>. The cylinder <NUM> includes a first chamber <NUM> including an internal space in which the plunger <NUM> moves back and forth and a second chamber <NUM> arranged on a side closer than the first chamber <NUM> in a forward direction of the plunger <NUM>.

As illustrated in <FIG>, a pressure sensor <NUM> for detecting the pressure of the viscous material M filled in the cylinder <NUM> is arranged in the first chamber <NUM>. The type, structure, arrangement, and the like of the pressure sensor <NUM> are not particularly limited as long as the pressure of the viscous material M in the cylinder <NUM> can be detected (measured).

Bearings 47a and 47b of the plunger <NUM> are arranged in the internal space of the first chamber <NUM>. As the bearings 47a and 47b, for example, a known O-ring made of a resin material or the like can be used.

A valve rod <NUM> included in the supply valve <NUM> is arranged in the second chamber <NUM>. The second chamber <NUM> communicates with the liquid supply pump <NUM> through a material supply passage. The liquid supply pump <NUM> can be configured by, for example, a known fluid pump which can pressure-feed the viscous material M.

When the supply of the viscous material M to the cylinder <NUM> is stopped (limited), a valve rod <NUM> of the supply valve <NUM> is seated on a valve seat <NUM> arranged in the second chamber <NUM> (for example, the state of <FIG>). When the valve rod <NUM> of the supply valve <NUM> is seated on the valve seat <NUM>, the communication between the liquid supply pump <NUM> and the second chamber <NUM> is interrupted. On the other hand, the supply valve <NUM> separates the valve rod <NUM> from the valve seat <NUM> when the viscous material M is supplied to the cylinder <NUM> (for example, the state of <FIG>). When the valve rod <NUM> is separated from the valve seat <NUM>, the liquid supply pump <NUM> and the second chamber <NUM> communicate with each other, and thus the viscous material M can be supplied to the second chamber <NUM>.

As illustrated in <FIG>, the second chamber <NUM> of the cylinder <NUM> communicates with the discharge chamber <NUM> through a material supply passage. The nozzle <NUM> is attached to the discharge chamber <NUM>. The internal space of the discharge chamber <NUM> and the flow path (not illustrated) formed in the nozzle <NUM> communicate with each other.

The discharge device <NUM> includes a discharge valve <NUM> which controls the discharge of the viscous material M from the nozzle <NUM>. A valve rod <NUM> included in the discharge valve <NUM> is arranged in the discharge chamber <NUM>. When the discharge of the viscous material M through the nozzle <NUM> is stopped (limited), the valve rod <NUM> of the discharge valve <NUM> is seated on the valve seat <NUM> arranged in the discharge chamber <NUM> (for example, the state of <FIG>). Further, when the viscous material M is discharged through the nozzle <NUM>, the discharge valve <NUM> separates the valve rod <NUM> from the valve seat <NUM> (for example, the state of <FIG>). When the valve rod <NUM> is separated from the valve seat <NUM>, the discharge chamber <NUM> and the internal flow path of the nozzle <NUM> communicate with each other, and thus the viscous material M can be discharged through the nozzle <NUM>.

The motor <NUM> included in the discharge device <NUM> can be configured by, for example, a known stepping motor. The motor <NUM> rotationally drives the power transmission mechanism <NUM>, thereby moving the ball screw <NUM> connected to the power transmission mechanism <NUM> back and forth.

The power transmission mechanism <NUM> includes a drive gear <NUM> connected to the motor <NUM>, and a driven gear <NUM> engaging with the drive gear <NUM>. The drive gear <NUM> for example, can be connected to the motor <NUM> through a clutch mechanism (not illustrated).

The driven gear <NUM> is engaged with the ball screw <NUM>. When the motor <NUM> rotationally drives the drive gear <NUM>, the driven gear <NUM> rotates in association with the rotation of the drive gear <NUM>, and the ball screw <NUM> also rotates. In the discharge device <NUM>, when the motor <NUM> is operated to rotate (for example, normally rotate) the ball screw <NUM> in one rotation direction, the ball screw <NUM> can be advanced toward the cylinder <NUM>. Further, in the discharge device <NUM>, when the motor <NUM> is operated to rotate (for example, reversely rotate) the ball screw <NUM> in another rotation direction, the ball screw <NUM> can be moved (move upward in <FIG>, hereinafter, also referred to as "raise") from the cylinder <NUM> in a retreating direction.

In the discharge device <NUM> according to this embodiment, the ball screw <NUM> and the plunger <NUM> are not connected. In other words, the ball screw <NUM> and the plunger <NUM> are not connected to each other through a mechanical connection structure for integrally moving the ball screw and the plunger back and forth. Therefore, the ball screw <NUM> can move back and forth independently of the plunger <NUM>. For example, as illustrated in <FIG>, in the discharge device <NUM>, when the ball screw <NUM> is retreated independently to the plunger <NUM>, a lower end <NUM> of the ball screw <NUM> can be arranged at a position separated from an upper end <NUM> of the plunger <NUM>.

By moving the plunger <NUM> forward in the cylinder <NUM>, the plunger <NUM> pressurizes the viscous material M supplied into the cylinder <NUM> to pressure-feed the viscous material M to the nozzle <NUM>.

As illustrated in <FIG>, in the discharge device <NUM>, when the ball screw <NUM> is normally rotated at the time of advancing the plunger <NUM>, the lower end <NUM> of the ball screw <NUM> is brought into contact with and presses the upper end <NUM> of the plunger <NUM>. Further, as illustrated in <FIG>, in the discharge device <NUM>, when the plunger <NUM> is retreated, the ball screw <NUM> is arranged at a predetermined position P1 apart from the plunger <NUM>, and a gap (space) g is formed between the lower end <NUM> of the ball screw <NUM> and the upper end <NUM> of the plunger <NUM>. As illustrated in <FIG>, the discharge device <NUM> supplies the viscous material M into the cylinder <NUM> in a state where the gap g is formed and increases the internal pressure of the cylinder <NUM>. The plunger <NUM> rises in the cylinder <NUM> so as to approach the ball screw <NUM> as the internal pressure of the cylinder <NUM> increases.

As illustrated in <FIG>, the cylinder <NUM> includes a support member <NUM> attached a photoelectric sensor <NUM>. As the support member <NUM>, for example, a rod-shaped member made of a metal material such as aluminum can be used.

The discharge device <NUM> includes a photoelectric sensor <NUM> arranged in the support member <NUM> included in the cylinder <NUM>. As the photoelectric sensor <NUM>, for example, a known photoelectric sensor such as a transmissive sensor, a retroreflective sensor, or a diffuse reflective sensor can be used. In particular, it is preferable to use a transmissive photoelectric sensor. Further, for example, the photoelectric sensor <NUM> can be arranged in the support member <NUM> so that the detection light is emitted from the support member <NUM> side to the ball screw <NUM> side.

The photoelectric sensor <NUM> is used to detect whether or not the viscous material M is filled in the cylinder <NUM> to the maximum extent. For example, the photoelectric sensor <NUM> detects the position of the upper end <NUM> of the plunger <NUM> as illustrated in <FIG>.

In this embodiment, the maximum filling amount of the viscous material M in the cylinder <NUM> can be defined as a movement amount of the plunger <NUM> to the position which the upper end <NUM> of the plunger <NUM> is in contact with the lower end <NUM> of the ball screw <NUM> when the ball screw <NUM> is retreated to the predetermined position P1. That is, the maximum filling amount of the viscous material M in the cylinder <NUM> is the empty volume of the cylinder <NUM> corresponding to the upward movable amount of the plunger <NUM> in a state where the lower end <NUM> of the ball screw <NUM> is separated from the upper end <NUM> of the plunger <NUM>. Therefore, as illustrated in <FIG>, by detecting the position where the upper end <NUM> of the plunger <NUM> is brought into contact with the lower end <NUM> of the ball screw <NUM>, the photoelectric sensor <NUM> can detect whether or not the viscous material M is filled in the cylinder <NUM> to the maximum extent.

As illustrated in <FIG>, the discharge device <NUM> includes a forward position detection sensor <NUM> which detects whether or not the ball screw <NUM> reaches to a forward position which is positioned in the plunger <NUM> side by a predetermined distance, a backward position detection sensor <NUM> which detects whether or not the ball screw <NUM> reaches to a back ward position which is positioned by a predetermined distance from the plunger <NUM>.

The forward position detection sensor <NUM> and the backward position detection sensor <NUM> are arranged at a predetermined interval in the back-and-forth direction (the vertical direction in <FIG>) of the ball screw <NUM>. Further, the backward position detection sensor <NUM> is arranged on a side (upper side in the drawing) closer than the forward position detection sensor <NUM> in a backward direction of the ball screw <NUM>. The forward position detection sensor <NUM> and the backward position detection sensor <NUM> can be arranged, for example, on the upper end side of the support member <NUM> to which the photoelectric sensor <NUM> is attached.

As illustrated in <FIG>, the forward position detection sensor <NUM> detects the position of the upper end <NUM> of the ball screw <NUM> and detects the distance where the ball screw <NUM> advances with respect to the plunger <NUM>. Specifically, the forward position detection sensor <NUM> detects that the plunger <NUM> advances by the distance between the forward position detection sensor <NUM> and the backward position detection sensor <NUM>. For example, the forward position detection sensor <NUM> can be arranged so as to detect the forward position of the ball screw <NUM> at which the discharge amount of the viscous material M through the nozzle <NUM> reaches a desired amount.

As illustrated in <FIG>, the backward position detection sensor <NUM> detects the position of the upper end <NUM> of the ball screw <NUM> and detects the distance where the ball screw <NUM> retreats with respect to the plunger <NUM>. Specifically, the backward position detection sensor <NUM> detects that the plunger <NUM> retreats by the distance between the forward position detection sensor <NUM> and the backward position detection sensor <NUM>. For example, the backward position detection sensor <NUM> can be arranged so as to detect the predetermined position P1 of the ball screw <NUM> at which the filling amount of the viscous material M in the cylinder <NUM> is maximum.

As the forward position detection sensor <NUM> and the backward position detection sensor <NUM>, for example, known transmissive or reflective photosensors can be used. However, the type, structure, arrangement, and the like of the sensors <NUM> and <NUM> are not particularly limited as long as the position of the ball screw <NUM> can be detected.

For example, the control unit <NUM> can be configured by a known PC including a CPU, a memory, an input/output interface, and the like. The control unit <NUM> transmits and receives various control signals S1 and executes the operation control of each of the sensors <NUM>, <NUM>, <NUM>, and <NUM>, the operation control of the motor <NUM>, the operation control of each of the valves <NUM> and <NUM>, the operation control of the liquid supply pump <NUM>, and the like.

Next, the discharge method of the viscous material M according to this embodiment will be described.

As illustrated in <FIG>, the discharge method of the viscous material M generally includes liquid supply preparation (S101), liquid supply (S102), internal pressure correction (S103), and discharge (S104). Hereinafter, the discharge method will be described in detail.

<FIG> illustrates the discharge device <NUM> before the viscous material M is supplied into the cylinder <NUM>. The supply valve <NUM> and the discharge valve <NUM> are closed as illustrated in <FIG> in the state before the liquid supply and the discharge.

When the viscous material M is supplied, the discharge device <NUM> prepares the liquid supply. Specifically, the discharge device <NUM> raises the ball screw <NUM> (retreats from the plunger <NUM>) as illustrated in <FIG>. As illustrated in <FIG>, the discharge device <NUM> raises the ball screw <NUM> until the lower end <NUM> of the ball screw <NUM> reaches the predetermined position P1. When the lower end <NUM> of the ball screw <NUM> reaches the predetermined position P1, the gap g is formed between the lower end <NUM> of the ball screw <NUM> and the upper end <NUM> of the plunger <NUM>. Whether or not the lower end <NUM> of the ball screw <NUM> reaches the predetermined position P1 can be confirmed by detecting the upper end <NUM> of the ball screw <NUM> by the backward position detection sensor <NUM>.

Incidentally, in this embodiment, the supply of the viscous material M is started in a state where the lower end <NUM> of the ball screw <NUM> reaches the predetermined position P1. However, for example, the liquid supply of the viscous material M to the cylinder <NUM> and the movement of the ball screw <NUM> may be executed in parallel. In such a case, for example, the timing at which the liquid supply of the viscous material M is started can be set to substantially the same as the timing at which the ball screw <NUM> rises (reversely rotate), for example, the timing of starting in parallel without a time difference in operation control. As described above, "the state in which the ball screw starts moving toward a predetermined position" may be any one of a state at the same time as the timing when the ball screw <NUM> starts moving or a state where a predetermined time has elapsed after the ball screw <NUM> starts moving.

The rising speed of the plunger <NUM> depends on the viscosity of the viscous material M. Meanwhile, since the ball screw <NUM> is not connected to the plunger <NUM>, the ball screw <NUM> can be raised independently. Therefore, the discharge device <NUM> does not need to strictly synchronize the rising speed of the ball screw <NUM> and the rising speed of the plunger <NUM>.

Next, as illustrated in <FIG>, the discharge device <NUM> starts the liquid supply. The discharge device <NUM> opens the supply valve <NUM>. The discharge device <NUM> operates the liquid supply pump <NUM> to supply the viscous material M to the cylinder <NUM>. The plunger <NUM> rises toward the ball screw <NUM> when the internal pressure of the cylinder <NUM> increases with the supply of the viscous material M into the cylinder <NUM>. Therefore, the discharge device <NUM> does not need to strictly control the moving speed of the plunger <NUM> so as to follow the increase in the liquid supply amount of the viscous material M into the cylinder <NUM>.

Incidentally, if the rise of the ball screw <NUM> and the rise of the plunger <NUM> are controlled according to the increase of the internal pressure of the cylinder <NUM> while the internal pressure of the cylinder <NUM> is monitored, the following problems may occur. For example, when astringent (the bearings 47a and 47b are worn due to deterioration over time or the like, and the viscous material M leaks and hardens) occurs near the bearings 47a and 47b, a resistance which prevents the plunger <NUM> from rising is generated, and the ball screw <NUM> and the plunger <NUM> may be unintentionally arranged to be separated from each other in a stage where the liquid supply into the cylinder <NUM> is completed. In particular, in the discharge device <NUM>, in a case where the liquid supply or the like is performed after a predetermined time has elapsed after the initial liquid supply, the resistance which prevents the movement of the plunger <NUM> is increased due to the effect of the hardening of the viscous material M (for example, in a case where the viscous material M is a moisture-curable material). As a result, when the discharge of the viscous material M by the discharge device <NUM> is started, a displacement occurs in the initial discharge position (initial applying position) depending on the distance between the ball screw <NUM> and the plunger <NUM>, the discharge is delayed at the start of discharge, and a desired overlap portion is hardly formed.

As illustrated in <FIG>, the plunger <NUM> rises until the upper end <NUM> of the plunger <NUM> is brought into contact with the lower end <NUM> of the ball screw <NUM>. When the upper end <NUM> of the plunger <NUM> is in contact with the lower end <NUM> of the ball screw <NUM>, the supply of the viscous material M to the cylinder <NUM> is stopped. That is, at this stage, the cylinder <NUM> is filled with the maximum amount of the viscous material M. The photoelectric sensor <NUM> detects whether or not the viscous material M is filled in the cylinder <NUM> to the maximum extent by detecting the position of the plunger <NUM>.

Next, the discharge device <NUM> corrects the internal pressure of the cylinder <NUM>. Specifically, as illustrated in <FIG>, the discharge device <NUM> raises the ball screw <NUM> with the supply valve <NUM> and the discharge valve <NUM> closed. As illustrated in <FIG>, the plunger <NUM> rises with the rise of the ball screw <NUM> by the internal pressure of the cylinder <NUM>. As a result, the internal pressure of the cylinder <NUM> drops to a desired value. The pressure sensor <NUM> detects the internal pressure of the cylinder <NUM>. Accordingly, the discharge device <NUM> can confirm that the internal pressure of the cylinder <NUM> is adjusted to the desired value before the discharge of the viscous material M is started.

Next, the discharge device <NUM> starts discharging the viscous material M. The discharge device <NUM> opens the discharge valve <NUM>. Then, in the discharge device <NUM>, when the ball screw <NUM> is lowered in a state where the lower end <NUM> of the ball screw <NUM> is in contact with the upper end <NUM> of the plunger <NUM> (abutted state), the plunger <NUM> can be lowered synchronously with the lowering of the ball screw <NUM>. The viscous material M filled in the cylinder <NUM> is applied on a predetermined applying target through the nozzle <NUM>. The discharge of the viscous material M is continued until, for example, the upper end <NUM> of the ball screw <NUM> is detected by the forward position detection sensor <NUM>.

The effects of the discharge device <NUM> and the liquid supply method according to this embodiment will be described.

As described above, the discharge device <NUM> according to this embodiment is a device which discharges the viscous material M from the nozzle <NUM> communicating with the cylinder <NUM> by pressurizing the viscous material M supplied to the cylinder <NUM>. The discharge device <NUM> includes the supply valve <NUM> which controls the supply of the viscous material M to the cylinder <NUM>, the plunger <NUM> which applies a pressure to the viscous material M supplied to the cylinder <NUM>, the ball screw <NUM> which is movable in the same direction as the back-and-forth direction of the plunger <NUM>, and the motor <NUM> which is connected to the ball screw <NUM> through the power transmission mechanism <NUM>. The plunger <NUM> and the ball screw <NUM> are not connected.

According to the discharge device <NUM>, the ball screw <NUM> connected to the motor <NUM> through the power transmission mechanism <NUM> is not connected to the plunger <NUM>. Then, when the viscous material M is supplied into the cylinder <NUM>, the plunger <NUM> retreats in the cylinder <NUM> due to the pressurization by the viscous material M supplied into the cylinder <NUM>. Therefore, the discharge device <NUM> does not need to strictly synchronize the amount (filling amount per unit time) of the viscous material M filled in the cylinder <NUM> with the speed at which the plunger <NUM> is retreated in the cylinder <NUM>, and thus the operation control of the plunger <NUM> is facilitated.

The supply valve <NUM> opens to supply the viscous material M to the cylinder <NUM> in a state where the ball screw <NUM> starts moving toward the predetermined position P1. Therefore, the viscous material M can be suitably supplied into the cylinder <NUM> without performing control for strictly synchronizing the moving speed of the ball screw <NUM> and the moving speed of the plunger <NUM>.

The discharge device <NUM> moves the ball screw <NUM> and supplies the viscous material M in parallel. Therefore, the viscous material M can be efficiently supplied.

The discharge device <NUM> includes the photoelectric sensor <NUM> which is arranged in the cylinder <NUM> and detects whether or not the viscous material M is filled in the cylinder <NUM> to the maximum extent. Therefore, in the discharge device <NUM> where the plunger <NUM> is moved according to the increase in the internal pressure of the cylinder <NUM>, the filling amount of the viscous material M into the cylinder <NUM> can be detected more accurately when the position of the plunger <NUM> is detected by the photoelectric sensor <NUM>.

The discharge device <NUM> includes the forward position detection sensor <NUM> which detects whether or not the ball screw <NUM> reaches to a forward position which is positioned in the plunger <NUM> side by a predetermined distance, the backward position detection sensor <NUM> which detects whether or not the ball screw <NUM> reaches to a back ward position which is positioned by a predetermined distance from the plunger <NUM>. Therefore, by detecting the position of the ball screw <NUM> by the sensors <NUM> and <NUM>, the discharge device <NUM> can control the adjustment of the filling amount of the viscous material M into the cylinder <NUM> and the adjustment of the discharge amount of the viscous material M from the nozzle <NUM> more accurately.

The discharge device <NUM> includes the discharge valve <NUM> which controls the discharge of the viscous material M through the nozzle <NUM>. Therefore, the discharge device <NUM> can appropriately switch the discharge of the viscous material M from the nozzle <NUM> and the restriction of the discharge by controlling the opening/closing of the discharge valve <NUM>.

The discharge device <NUM> includes the pressure sensor <NUM> which detects the pressure of the viscous material M supplied into the cylinder <NUM>. Therefore, in the discharge device <NUM>, the internal pressure correction of adjusting the internal pressure of the cylinder <NUM> to the desired value before starting the discharge of the viscous material M can be performed by monitoring the internal pressure of the cylinder <NUM> by the pressure sensor <NUM>.

The liquid supply method according to this embodiment is a liquid supply method of supplying the viscous material M to the discharge device <NUM>. The discharge device <NUM> includes the supply valve <NUM> which controls the supply of the viscous material M to the cylinder <NUM>, the plunger <NUM> which applies a pressure to the viscous material M supplied to the cylinder <NUM>, the ball screw <NUM> which is movable in the same direction as the back-and-forth direction of the plunger <NUM>, and the motor <NUM> which is connected to the ball screw <NUM> through the power transmission mechanism <NUM>. Further, the plunger <NUM> of the discharge device <NUM> is not connected to the ball screw <NUM>, and the viscous material M is supplied by opening the supply valve <NUM> in a state where the ball screw <NUM> starts moving.

According to the above-described liquid supply method, the plunger <NUM> moves to a position in contact with the ball screw <NUM> in accordance with the supply of the viscous material into the cylinder <NUM>, and advances in the cylinder <NUM> in linkage with the advance of the ball screw <NUM> at the time of starting discharging the viscous material M. Therefore, in the discharge device <NUM> in which the plunger <NUM> and the ball screw <NUM> are not connected, the advance of the ball screw <NUM> and the advance of the plunger <NUM> can be appropriately synchronized when the discharge of the viscous material M is started, and thus it is possible to form a desired overlap portion (the overlapping portion of the initial applying portion and the final applying portion of the viscous material).

In the liquid supply method, the photoelectric sensor <NUM> included in the discharge device <NUM> detects whether or not the viscous material M is filled in the cylinder <NUM> to the maximum extent. Therefore, in the liquid supply method, the filling amount of the viscous material M into the cylinder <NUM> can be detected more accurately when the position of the plunger <NUM> is detected by the photoelectric sensor <NUM> in the discharge device <NUM> in which the plunger <NUM> is moved according to the increase in the internal pressure of the cylinder <NUM>.

Hereinbefore, the discharge device and the liquid supply method according to the present invention have been described above through the embodiments. However, the present invention is not limited to the contents described in the specification and may be appropriately modified within the scope of the claims.

Claim 1:
A discharge device (<NUM>) which discharges a viscous material (M) from a nozzle (<NUM>) communicating with a cylinder (<NUM>) by pressurizing the viscous material (M) supplied to the cylinder (<NUM>), the device (<NUM>) comprising:
a supply valve (<NUM>) which controls a supply of the viscous material (M) to the cylinder (<NUM>);
a plunger (<NUM>) which applies a pressure to the viscous material (M) supplied to the cylinder (<NUM>);
a ball screw (<NUM>) which is movable in a same direction as a back-and-forth direction of the plunger (<NUM>);
a motor (<NUM>) which is connected to the ball screw (<NUM>) through a power transmission mechanism (<NUM>), characterized by
a pressure sensor (<NUM>) which is arranged in the cylinder (<NUM>) and detects a pressure of the viscous material (M) supplied into the cylinder (<NUM>),
wherein the discharge device (<NUM>) is configured to correct the internal pressure of the cylinder (<NUM>) by raising the ball screw (<NUM>) with the supply valve (<NUM>) being closed to drop the internal pressure of the cylinder (<NUM>) to a desired value after the viscous material (M) is supplied to the cylinder (<NUM>),
wherein the pressure sensor (<NUM>) is configured to detect the internal pressure of the cylinder (<NUM>) after correcting the internal pressure, and wherein
the plunger (<NUM>) and the ball screw (<NUM>) are not connected.