JP5374303B2 - Pump device - Google Patents

Description

  The present invention relates to a pump device capable of continuously delivering paint by rotational movement and reciprocating movement of an outer piston sliding in a cylinder body.

  Conventionally, various pumps such as a gear pump and a vane pump are known as pump devices for delivering liquid. In such a conventional pump device, for example, when the amount of liquid delivered in one cycle is small, it is difficult to accurately control the amount of liquid delivered.

  Therefore, the present applicant has proposed a delivery adjustment mechanism for a delivery pump capable of efficiently and accurately controlling the amount of delivered liquid regardless of the amount of delivered liquid (see Patent Document 1). .

JP 2001-115951 A

  By the way, when the delivery pump proposed in Patent Document 1 is applied to a known electrostatic coating system, the delivery pump intermittently discharges paint (liquid) from a coating gun to an object to be coated. Therefore, it is preferable to continuously and stably discharge the paint.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a pump device capable of continuously and stably discharging paint on an object to be coated.

In order to achieve the above object, the present invention provides a cylinder body provided with a suction port through which fluid is introduced and a delivery port through which fluid is led out, and an outer piston and a piston slidably provided in the cylinder body. A rod, an inner piston fixed in the cylinder body, a rotating mechanism for rotating the outer piston around the axis of the piston rod, and the outer piston reciprocating along the axial direction of the piston rod. A reciprocating mechanism; a communication means provided on the outer piston and communicating with the first chamber and the second chamber in the cylinder body divided by the outer piston; and provided on a piston rod of the outer piston. While rotating in the circumferential direction integrally with the outer piston, it reciprocates along the axial direction of the piston rod. And a shielding means for closing said suction port,
The shielding means opens the suction port only at an intermediate position where the outer piston is displaced from one end portion along the axial direction of the cylinder body toward the other end portion, and the outer piston is opened from the one end portion to the other end. The suction port is closed when it is at a position other than the intermediate position that is displaced toward the part, and the communication means is configured such that the outer piston moves from the other end along the axial direction of the cylinder body toward one end. When the first chamber and the second chamber are in communication with each other only at an intermediate position where the outer piston is displaced, and the outer piston is in a position other than the intermediate position where the outer piston is displaced from the other end toward the one end. the communication state between the second chamber and the first chamber is blocked by the inner piston, the first chamber is provided so as to communicate with the suction port, the second chamber is the delivery Pau The volume of the first chamber is set larger than the volume of the second chamber, and excess fluid corresponding to the volume difference of the fluid flowing from the first chamber into the second chamber is It is derived from the delivery port and said Rukoto.

  According to the present invention, the rotating mechanism and the reciprocating mechanism are driven to perform the reciprocating motion in the axial direction in synchronization with the rotational motion around the axis of the outer piston, and the outer piston is aligned with the axial direction of the cylinder body. Since the suction port is opened by the shielding means at the intermediate position displaced from the one end (upper end) toward the other end (lower end), fluid is introduced from the suction port into the first chamber of the cylinder body, The communication state between the first chamber and the second chamber is blocked by the communication means, and the fluid filled in the second chamber is pressurized by the displacement of the outer piston, and is discharged from the delivery port.

  Contrary to the above, at the intermediate position where the outer piston is displaced from the other end (lower end) toward one end (upper end), the suction port is closed by the shielding means to prevent the back flow, so The fluid filled in the one chamber is pressurized, and the first chamber and the second chamber are communicated with each other by the communication means, and the pressurized fluid in the first chamber is filled in the second chamber. It is discharged from the delivery port.

Thus, in the present invention, the outer piston is displaced from the one end (upper end) along the axial direction of the cylinder body toward the other end (lower end), and the outer piston is moved from the other end (lower end) to the one end. With both strokes displaced toward (upper end), fluid (for example, paint) can be continuously and stably discharged to the object to be coated.
Further, according to the present invention, the first chamber is provided so as to communicate with the suction port, the second chamber is provided so as to communicate with the delivery port, and the volume of the first chamber is larger than the volume of the second chamber. By setting, the surplus fluid corresponding to the volume difference of the fluid flowing into the second chamber from the first chamber can be derived from the delivery port.

  Further, according to the present invention, the shielding means includes a shielding member externally fitted to the piston rod of the outer piston, and the shielding member has a notch space portion formed in a fan shape in plan view. A rotational position in which the notch space portion of the shielding member faces the suction port at an intermediate position that is made of a cylindrical body and the outer piston is displaced from one end portion along the axial direction of the cylinder body toward the other end portion. It is good to set so that.

  Further, according to the present invention, the communication means has a communication flow path formed in the outer piston and a notch formed in the inner piston, and the outer piston extends along the axial direction of the cylinder body. It is good to set so that the above-mentioned communicating channel turns into the rotation position which faces the above-mentioned notch part of the inner piston in the middle position displaced toward the one end part from the other end part.

  Furthermore, the present invention includes a cleaning port block connected to the cylinder body and provided with a cleaning chamber therein, and by introducing a cleaning agent into the cleaning chamber, the piston rod of the outer piston is axially cleaned. In addition, the cleaning port block may be provided with an annular brush member that is in sliding contact with the outer peripheral surface of the piston rod.

  ADVANTAGE OF THE INVENTION According to this invention, the pump apparatus which can discharge stably a coating material with respect to a to-be-coated object continuously is obtained.

It is a circuit block diagram of the coating material supply system with which the pump apparatus which concerns on embodiment of this invention was integrated. It is a schematic longitudinal cross-sectional view of the pump apparatus shown in FIG. (A), (b) is a principal part expanded side view which shows the state by which the front-end | tip part of the piston rod was supported so that rocking | fluctuation with respect to the rotating drum was possible. It is a side view which shows the state which inclined the pump main body by the predetermined angle using the inclination cylinder. (A), (b) is a schematic diagram which shows the relationship between the inclination-angle of a pump main body, and the stroke of an outer piston. (A) is a partially broken exploded perspective view showing the positional relationship of an inner piston, an outer piston, a shielding member, etc. constituting the pump device shown in FIG. 2, and (b) is a notch space formed in the shielding member. The cross-sectional view which shows the shape of this, (c) is a cross-sectional view which shows the modification of the said notch space part. The operation of the pump device is shown in time series, (1-a) to (4-a) are longitudinal sectional views showing the position of the outer piston, and (1-b) to (4-b) are , (1-c) to (4-c) are cross-sectional views taken along the horizontal plane that passes through the suction port at each position of the outer piston, and (1-c) to (4-c) show the lower end opening of the paint communication flow path at each position of the outer piston. It is a cross-sectional view which makes a horizontal plane which passes through a cut surface. The operation of the pump device following FIG. 7 is shown in time series, (5-a) to (8-a) are longitudinal sectional views showing the position of the outer piston, and (5-b) to (8 -B) is a cross-sectional view with a horizontal plane passing through the suction port at each position of the outer piston as a cut surface, and (5-c) to (8-c) are lower ends of the paint communication flow paths at each position of the outer piston. It is a cross-sectional view which makes the horizontal surface which passes a side opening part a cut surface. It is a schematic structure sectional view of a washing mechanism attached to a pump body. It is a circuit block diagram of the coating material supply system which concerns on the modification in which the pump apparatus which concerns on embodiment of this invention was integrated.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. FIG. 1 is a circuit configuration diagram of a paint supply system in which a pump device according to an embodiment of the present invention is incorporated, and FIG. 2 is a schematic longitudinal sectional view of the pump device shown in FIG.

  As shown in FIG. 1, the paint supply system 10 includes a pair of first pump device 12a and second pump device 12b having the same configuration, and paint supplied from the first pump device 12a and second pump device 12b. A coating gun 14 that discharges (fluid) toward an object (not shown) (for example, an automobile body) and a cleaning mechanism 16 that cleans the first pump device 12a, the second pump device 12b, and the like are provided.

  The paint supply system 10 includes one paint derived from the first pump device 12a (for example, a paint composed of a main agent) and the other paint derived from the second pump device 12b (for example, a curing agent). This is a system in which two paints made of paint are mixed, and paint (mixed paint) is continuously discharged from the paint gun 14 toward an object not shown. In addition, when not referring to the individual pump devices composed of the first pump device 12a and the second pump device 12b, but collectively referring to both, the pump device 12 is hereinafter described.

  The paint supply system 10 is connected to the output side of the first pump device 12a and the output side of the second pump device 12b, merges at the downstream side and communicates with the coating gun 14; And a static mixer 20 for sequentially stirring and mixing the two liquids joined by an element (not shown). The static mixer 20 is constituted by, for example, a static mixer.

FIG. 9 is a schematic sectional view of a cleaning mechanism attached to the pump body. Hereinafter, the cleaning mechanism 16 will be described in detail with reference to FIGS. 1 and 9 together.
As shown in FIG. 1, the cleaning mechanism 16 is connected to the cleaning agent supply source 22 to store a predetermined amount of cleaning agent, and to the cleaning agent tank 24 through a cleaning passage 26. Supply of cleaning agent to the first cleaning valve 28a and the second pumping device 12b, which are connected and switch-controlling the supply state and supply stop state of the cleaning agent to the first pump device 12a based on a control signal from a controller (not shown). A second cleaning valve 28b that switches between a state and a supply stop state, and a mixer cleaning valve 28c that switches between a supply state and a supply stop state of the cleaning agent for the static mixer 20.

The cleaning mechanism 16 is connected to a cleaning port block 43 to be described later via a fluid passage 38, and is disposed in the fluid passage 38 and a nitrogen generator 37 that generates nitrogen (N ₂ ). Opening and closing valves 40a and 40b for switching between a supply state and a supply stop state of nitrogen generated by the nitrogen generator 37 by opening and closing 38 are provided.

  Further, as shown in FIG. 9, the cleaning mechanism 16 includes a cleaning port block 43 integrally connected to an upper end portion (one end portion) along the axial direction of the pump main body 32 and having a cleaning port 41. An annular brush member 45 that surrounds a piston rod 58 of an outer piston 56, which will be described later, and performs shaft cleaning while being in sliding contact with the outer peripheral surface of the piston rod 58 is mounted inside the cleaning port block 43.

  In this case, the cleaning chamber 47 provided in the cleaning port block 43 is filled with nitrogen generated by the nitrogen generator 37 to prevent the paint (liquid) from drying and sticking, and the brush. The outer surface of the piston rod 58 is cleaned by the member 45. By providing this cleaning mechanism 16, for example, electrical leakage can be prevented and electrostatic insulation can be improved when electrostatic coating is performed.

  Returning to FIG. 1, the first pump device 12 a and the second pump device 12 b have the same configuration, and suck the paint stored in the storage tank 31 through the paint suction passage 30 to remove the sucked paint. It has a pump main body 32 that feeds toward the coating gun 14 side, a rotary drum 34, and a motor 36 that consists of a rotational drive source such as an AC servo motor. The rotating drum 34 and the motor 36 function as a rotating mechanism.

  As shown in FIG. 2, the pump body 32 includes a cylinder tube 42 formed in a substantially cylindrical shape, and a port block integrally coupled to one end portion (upper end portion) along the axial direction of the cylinder tube 42. 44 and an end block 46 integrally coupled to the other end portion (lower end portion) along the axial direction of the cylinder tube 42. In this case, the pump body 32, the cylinder tube 42, and the end block 46 function as a cylinder body. In FIG. 2, illustration of the cleaning port block 43 of the cleaning mechanism 16 is omitted.

  In this case, the port block 44 has a suction port 48 connected to the storage tank 31 via the paint suction passage 30 and a cleaning port 50 connected to the cleaning agent tank 24 via the cleaning passage 26. In addition, the end block 46 is provided with a delivery port 52 that is connected to the coating gun 14 via the communication path 18.

  Inside the cylinder tube 42 and the port block 44 are accommodated an outer piston 56 and a piston rod 58 that reciprocate in the axial direction along the inner wall of the cylinder tube 42 and can rotate in the circumferential direction. The piston rod 58 is provided so that one end thereof is exposed to the outside through the through hole 44 a of the port block 44.

  A seal ring 60 is attached to the through hole 44a of the port block 44 via an annular groove. The seal ring 60 surrounds the outer peripheral surface of the piston rod 58 so as to be slidable and rotatable, thereby exhibiting a sealing function. The Note that the outer piston 56 and the piston rod 58 may be integrally formed as shown in FIG. 2 or may be integrally assembled and connected separately.

  Further, a chamber 62 filled with the paint sucked from the suction port 48 is formed inside the cylinder tube 42 and the port block 44, and the chamber 62 is connected to the suction port 48 side by the outer piston 56. The first chamber 62a is divided into a lower second chamber 62b communicating with the delivery port 52 side.

  The volume ratio between the volume of the first chamber 62a on the suction port 48 side (upper side) and the volume of the second chamber 62b on the delivery port 52 side (lower side) should be set to about 2: 1, for example. Is preferred. However, the volume ratio is not limited, and the volume of the first chamber 62a may be set larger than the volume of the second chamber 62b. In the present embodiment, surplus paint can be discharged from the delivery port 52 using the volume difference between the first chamber 62a and the second chamber 62b. This will be described in detail later.

  A seal member 64 (for example, an O-ring or the like) is mounted on the outer peripheral surface of the outer piston 56 via an annular groove, and is sealed fluid-tight by the seal member 64, whereby the inner surface of the cylinder tube 42 and the outer piston are sealed. The fluid can be prevented from leaking through between the outer surfaces of 56.

  6A is a partially broken exploded perspective view showing the positional relationship of the inner piston, the outer piston, the shielding member, etc. constituting the pump device shown in FIG. 2, and FIG. 6B is formed on the shielding member. FIG. 6C is a cross-sectional view showing a modified example of the notch space portion.

  Further, the second chamber 62 b on the lower side of the cylinder tube 42 has a substantially cylindrical body, a lower end portion along the axial direction is fixed to the inner wall of the end block 46, and an upper end portion thereof is the axial direction of the cylinder tube 42. Is provided with an inner piston 66 extending toward the outer piston 56 side. The inner piston 66 is cut out in a circular arc shape when viewed from the axial direction of the piston rod 58 (in plan view), and is cut out by a predetermined length along the axial direction of the cylindrical body. 68 is formed (see FIG. 6A).

  The shape of the notch 68 of the inner piston 66 is preferably formed in an arc shape smaller than a semicircle in plan view. Further, the orientation of the notch 68 of the inner piston 66 and the orientation of the suction port 48 of the pump body 32 are set in the same or substantially the same direction in the circumferential direction when viewed from above (see FIG. 6A). ) And parallel to the axial direction when viewed from the side (see FIG. 2).

  The outer piston 56 is provided with a paint communication channel (communication channel) 70 that communicates the first chamber 62a and the second chamber 62b. The upper end opening 70a of the paint communication channel 70 is provided in the ceiling portion 56a of the outer piston 56 that faces the first chamber 62a and is close to the piston rod 58 (see FIGS. 2 and 6A). On the other hand, the lower end opening 70b of the paint communication channel 70 faces the notch 68 of the inner piston 66 provided on the second chamber 62b side, and the inner peripheral portion of the bottomed hole 56b formed in the outer piston 56. (See FIG. 2). The inner piston 66, the notch 68 and the paint communication channel 70 function as communication means.

  In this case, the inner diameter dimension of the inner peripheral part of the bottomed hole part 56b formed in the outer piston 56 is set slightly larger than the outer diameter dimension of the inner piston 66, and the bottomed hole part 56b of the outer piston 56 is The inner piston 66 is provided so as to be slidable along the axial direction and the circumferential direction in contact with the outer circumferential surface of the inner piston 66.

  A shielding member 72 having a substantially cylindrical shape is externally fitted on the outer peripheral surface of the piston rod 58, and the shielding member 72 has a notch space portion 71 (see FIG. 6A) having a fan-shaped cross section in plan view. ) Is formed. The shielding member 72 is fixed to the piston rod 58 and is displaced along the axial direction integrally with the piston rod 58 and is rotatably provided along the circumferential direction. In addition, the said shielding member 72 and the said notch space part 71 function as a shielding means.

  The shape of the cutout space 71 of the shielding member 72 is set to a fan shape having an arc smaller than a semicircle in plan view as shown in the cross-sectional view of FIG. As shown in the transverse sectional view of c), it may be formed in the notch space portion 71a having a substantially rectangular shape in plan view. Further, the direction of the cutout space portion 71 formed in the shielding member 72 is set so as to communicate with the suction port 48 only at the lower intermediate position where the outer piston 56 descends while rotating in the circumferential direction (see FIG. 6 (a), FIG. 7 (2-b), and FIG. 8 (6-b)).

  A cylindrical receiving member 74 having a receiving surface that contacts the outer surface of the shielding member 72 is fixed to the inner wall of the port block 44. The receiving member 74 is formed with a through hole 76 that allows the first chamber 62 a and the suction port 48 to communicate with each other.

  When the shielding member 72 externally fitted to the piston rod 58 of the outer piston 56 rotates a predetermined angle along the circumferential direction integrally with the piston rod 58 along the receiving surface (inner peripheral surface) of the receiving member 74, The outer peripheral surface of the shielding member 72 is positioned so as to face the suction port 48 depending on the rotation angle, so that the through hole 76 of the receiving member 74 is closed and the paint from the suction port 48 into the first chamber 62a of the pump main body 32. Inflow is blocked. On the other hand, the paint flows into the pump main body 32 from the suction port 48 when the notch space portion 71 of the shielding member 72 is positioned to face the suction port 48 according to the rotation angle. This will be described in detail later.

  3 (a) and 3 (b) are enlarged cross-sectional views of the main part showing a state in which the tip end of the piston rod is swingably supported with respect to the rotating drum, and FIG. 4 shows the pump body using an inclined cylinder. It is a side view which shows the state made to incline by the predetermined angle.

  As shown in FIGS. 3A and 3B, the rotary drum 34 is rotatably supported on the motor shaft 36 a of the motor 36 via a bearing 78. A well-known spherical bearing 80 to which a bent portion 58 a of the piston rod 58 of the outer piston 56 is connected is provided on the inner wall of the concave portion of the rotating drum 34, and the piston rod 58 can swing freely through the spherical bearing 80. Supported.

  In addition, as shown in FIG. 4, an inclined cylinder 84 is provided at a portion close to the pump main body 32 to incline the pump main body 32 by a predetermined angle with respect to the vertical direction by moving the rod 82 linearly. It is done. In this case, a pair of guide rails 86a and 86b extending substantially parallel to the axial direction of the pump main body 32 are provided on the outer peripheral surface of the pump main body 32, and are connected to the rod 82 by a connection pin or the like (not shown). The pump body 32 can be inclined at a predetermined angle by sliding the slider 88 along the pair of guide rails 86a and 86b. The tilt cylinder 84, the pair of guide rails 86a and 86b, and the slider 88 function as a reciprocating mechanism.

  FIGS. 5A and 5B are schematic views showing the relationship between the tilt angle of the pump body and the stroke of the outer piston. In FIG. 5, the length of the straight portion from the tip of the piston rod 58 connected to the spherical bearing 80 to the bent portion is D, and the inclination angles of the pump body 32 (piston rod 58) with respect to the vertical line V are α and β. Show. Here, the relationship between the stroke amounts ST1 and ST2 of the outer piston 56 and the inclination angles α and β is derived by the following equations (1) and (2).

ST1≈2 × D × tan α ··················································· Equation (1)
ST2 ≒ 2 x D x tanβ ········································································
However, α <β.
Therefore, ST1 <ST2.

  As guided by the equations (1) and (2), the stroke of the outer piston 56 increases as the rod 82 of the tilt cylinder 84 expands and the tilt angle of the pump body 32 (piston rod 58) with respect to the vertical line V increases. The amount increases. As a result, the stroke amount of the outer piston 56 can be set to a predetermined amount by adjusting the tilt angle.

  The paint supply system 10 in which the pump device 12 according to the present embodiment is incorporated is basically configured as described above. Next, the operation, action, and effect thereof will be described.

  7 and 8 are explanatory diagrams showing the operation of the first pump device (second pump device) in time series, and FIGS. 7 (1-a) to 7 (4-a) and FIG. 8 (5). -A) to FIG. 8 (8-a) are longitudinal sectional views showing the position of the outer piston, FIG. 7 (1-b) to FIG. 7 (4-b) and FIG. 8 (5-b) to FIG. 8-b) is a cross-sectional view with the horizontal plane passing through the suction port at each position of the outer piston as a cut surface, FIGS. 7 (1-c) to 7 (4-c) and FIG. 8 (5-c) to FIG. 8 (8-c) is a cross-sectional view with a horizontal plane passing through the lower end side opening of the paint communication channel at each position of the outer piston as a cut surface.

  7 and 8, when the outer piston 56 is at the highest position, the top dead center is set, and when the outer piston 56 is at the lowest position, the bottom dead center is set, and no paint is introduced into the pump body 32. The case where it is at the top dead center is described as the initial state. Moreover, in FIG.7 and FIG.8, the coating material with which the pump main body 32 was filled is shown with the halftone dot.

  By driving the motor 36 and the tilt cylinder 84 and reciprocating in the axial direction in synchronization with the rotational movement of the outer piston 56 around the axis, the outer piston is filled in the pump body 32 in an unfilled state. Starting from an initial state in which 56 is at the upper end, the outer piston 56 starts to descend in synchronization with the rotation. When the outer piston 56 is at the top dead center, the suction port 48 is shielded by the outer wall of the shielding member 72 as shown in FIG. The introduction of the paint into the interior is stopped, and the lower end side opening 70b of the paint communication channel 70 is closed by the outer wall of the inner piston 66, as shown in FIG. 7 (1-c).

  As shown in FIG. 7 (2-a), the outer piston 56 rotates about 90 degrees in the circumferential direction from the top dead center position, which is the initial state, and is a predetermined length toward the lower side (arrow X1 direction). By displacing, it becomes a descending intermediate position. In this lowered intermediate position, as shown in FIG. 7 (2-b), the suction port 48 is opened by the notch space portion 71 of the shielding member 72, and the first chamber of the pump body 32 is opened through the opened suction port 48. The paint is sucked into 62a. At this lowering intermediate position, as shown in FIG. 7 (2-c), the lower end side opening 70 b of the paint communication channel 70 is closed by the outer wall of the inner piston 66, The paint introduced into the first chamber 62a is blocked from being supplied into the second chamber 62b.

  Subsequently, as shown in FIG. 7 (3-a), the outer piston 56 rotates about 90 degrees in the circumferential direction from the lowered intermediate position and is further displaced downward (in the direction of the arrow X 1). The bottom dead center position. At this bottom dead center position, as shown in FIG. 7 (3-b), since the suction port 48 is shielded by the outer wall of the shielding member 72, the paint is introduced from the suction port 48 into the pump body 32. 7 is stopped, and as shown in FIG. 7 (3-c), the lower end side opening 70 b of the paint communication channel 70 is closed by the outer wall of the inner piston 66.

  Next, as shown in FIG. 7 (4-a), the outer piston 56 further rotates about 90 degrees in the circumferential direction from this bottom dead center position, and is a predetermined length toward the upper side (arrow X2 direction). By displacing, it becomes an ascending intermediate position. In this raised intermediate position, as shown in FIG. 7 (4-b), the suction port 48 is shielded by the outer wall of the shielding member 72, so that the paint introduced into the pump body 32 is outside the pump body 32. As shown in FIG. 7 (4-c), the lower end side opening 70 b of the paint communication flow path 70 is in communication with the notch 68 of the inner piston 66.

  Accordingly, at the intermediate position where the outer piston 56 is raised as shown in FIG. 7 (4-a), the first chamber 62a and the second chamber 62b in the pump body 32 are in communication with each other through the paint communication flow path 70, and the pre-process Thus, the paint previously filled in the first chamber 62a is supplied into the second chamber 62b, and a predetermined amount of paint is discharged from the delivery port 52. The volume ratio between the volume of the first chamber 62a and the volume of the second chamber 62b is set to about 2: 1, and the volume is introduced from the first chamber 62a having a larger volume into the second chamber 62b having a smaller volume. Excess paint is discharged from the delivery port 52.

  Subsequently, as shown in FIG. 8 (5-a), the outer piston 56 rotates about 90 degrees in the circumferential direction from this ascending intermediate position and is displaced by a predetermined length toward the upper side (arrow X2 direction). As a result, it becomes the top dead center position. At this top dead center position, as shown in FIG. 8 (5-b), the suction port 48 is shielded by the outer wall of the shielding member 72, so that the paint is introduced from the suction port 48 into the pump body 32. 8 is stopped, and the lower end side opening 70b of the paint communication channel 70 is closed by the outer wall of the inner piston 66, as shown in FIG. The paint filling the second chamber 62b in the pump body 32 is prevented from flowing back to the first chamber 62a because the lower end opening 70b of the paint communication channel 70 is closed.

  Subsequently, as shown in FIG. 8 (6-a), the outer piston 56 rotates about 90 degrees in the circumferential direction from this top dead center position and is displaced by a predetermined length in the downward direction (arrow X 1 direction). By doing so, the intermediate position is lowered. In this lowered intermediate position, as shown in FIG. 8 (6-b), the suction port 48 is opened by the notch space portion 71 of the shielding member 72, and the first chamber of the pump body 32 is opened through the opened suction port 48. The paint is sucked into 62a. In this lowering intermediate position, as shown in FIG. 8 (6-c), the lower end side opening 70 b of the paint communication channel 70 is closed by the outer wall of the inner piston 66, so The paint introduced into the chamber 62a is prevented from being supplied into the second chamber 62b. Further, when the outer piston 56 is lowered, the paint filled in the second chamber 62 b is pressurized, and the paint corresponding to the displacement amount of the outer piston 56 is discharged from the delivery port 52.

  Subsequently, as shown in FIG. 8 (7-a), the outer piston 56 rotates about 90 degrees in the circumferential direction from the lowered intermediate position and is further displaced toward the lower side (arrow X1 direction). The bottom dead center position. At this bottom dead center position, as shown in FIG. 8 (7-b), since the suction port 48 is shielded by the outer wall of the shielding member 72, the paint is introduced from the suction port 48 into the pump body 32. As shown in FIG. 8 (7-c), the lower end opening 70b of the paint communication channel 70 is closed by the outer wall of the inner piston 66, and the first chamber 62a and the second chamber 62b. Communication with is interrupted. Further, when the outer piston 56 descends from the lowering intermediate position to the bottom dead center position, the paint filled in the second chamber 62b is pressurized, and the paint corresponding to the displacement amount of the outer piston 56 is delivered to the delivery port. 52 is discharged.

  Next, as shown in FIG. 8 (8-a), the outer piston 56 rotates about 90 degrees in the circumferential direction from this bottom dead center position and is displaced by a predetermined length toward the upper side (arrow X 2 direction). As a result, the intermediate position is raised. In this raised intermediate position, as shown in FIG. 8 (8-b), the suction port 48 is shielded by the outer wall of the shielding member 72, so that the paint introduced into the pump body 32 is outside the pump body 32. As shown in FIG. 8 (8-c), the lower end side opening 70 b of the paint communication channel 70 is in communication with the notch 68 of the inner piston 66.

  Therefore, at the middle position where the outer piston 56 is lifted as shown in FIG. 8 (8-a), the first chamber 62a and the second chamber 62b in the pump body 32 are in communication with each other through the paint communication channel 70 and suction is performed. The port 48 is closed by the shielding member 72. As a result, the paint previously filled in the first chamber 62a is pressurized by the rise of the outer piston 56 and is supplied into the second chamber 62b through the paint communication channel 70 (because the suction port 48 is closed). In addition, a predetermined amount (excess paint) of the paint supplied into the second chamber 62b due to the volume difference between the first chamber 62a and the second chamber 62b is discharged from the delivery port 52. The Thereafter, the process consisting of the upper dead center position → the lower intermediate position → the lower dead center position → the upper intermediate position of the outer piston 56 is sequentially repeated.

  Thus, in the present embodiment, the outer piston 56 rotates along the circumferential direction and reciprocates along the axial direction of the pump body 32, so that the outer piston 56 changes from the top dead center to the bottom dead center. In both the downward stroke and the other stroke in which the outer piston 56 rises from the bottom dead center to the top dead center, the paint can be continuously and stably discharged from the delivery port 52.

  The paint discharged from the delivery port 52 of each pump body 32 of the first pump device 12a and the second pump device 12b joins through the communication passage 18 and is stirred and mixed through the static mixer 20, and then introduced into the coating gun 14. Then, it is continuously sprayed from the painting gun 14 toward an object to be painted such as a vehicle body.

The pump device 12 according to the present embodiment includes a pump body 32, a cylinder tube 42 and an end block 46 provided with a suction port 48 into which paint is introduced and a delivery port 52 through which paint is led out,
An outer piston 56 and a piston rod 58 slidably provided in the cylinder tube 42;
An inner piston 66 fixed in the cylinder tube 42;
A motor 36 and a rotating drum 34 for rotating the outer piston 56 around the axis of the piston rod 58;
An inclined cylinder 84 for reciprocating the outer piston 56 along the axial direction of the piston rod 58;
A paint communication flow path 70 provided in the outer piston 56 for communicating the first chamber 62a and the second chamber 62b in the cylinder tube 42 divided by the outer piston 56;
A shield that is provided on the piston rod 58 of the outer piston 56 and rotates in the circumferential direction integrally with the outer piston 56 and reciprocates along the axial direction of the piston rod 58 to block the suction port 48. Member 72;
With
The shielding member 72 is shielded only at a lower intermediate position where the outer piston 56 is displaced from the top dead center (one end) along the axial direction of the cylinder tube 42 toward the bottom dead center (the other end). The suction port 48 is opened through the notch space portion 71 of the member 72 (see FIGS. 7 (2-a), (2-b), FIG. 8 (6-a), (6-b)), and When the outer piston 56 is at a position (for example, top dead center, bottom dead center, middle lift) other than the lowering middle position that is displaced from the top dead center (one end) toward the bottom dead center (the other end) The suction port 48 is closed (see FIG. 7 (1-b), (3-b), (4-b), FIG. 8 (5-b), (7-b), (8-b)),
The paint communication flow path 70 is provided only at the rising intermediate position where the outer piston 56 is displaced from the bottom dead center (the other end) along the axial direction of the cylinder tube 42 toward the top dead center (the one end). The first chamber 62a and the second chamber 62b are in communication with each other through the notch 68 of the inner piston 66 (see FIGS. 7 (4-c) and 8 (8-c)), and the outer When the piston 56 is in a position other than the rising intermediate position where the piston 56 is displaced from the bottom dead center (the other end) toward the top dead center (the one end), the peripheral wall of the inner piston 66 causes the first chamber 62a to The communication state with the second chamber 62b is provided to be blocked.

  In the present embodiment, the paint sucked from the suction port 48 by the cooperative action of the movable outer piston 56 and the fixed inner piston 66 can be continuously and stably dispensed from the delivery port 52. , Painting efficiency is improved.

  In addition, the paint used in the present embodiment may be a normal paint (oil-based paint) or an aqueous paint used for electrostatic painting (either an internal application method or an external application method). . Here, the water-based paint will be described in detail.

  In water-based paints, the thinner used in oil-based paints as a diluent switches to water. In general, since water and oil do not mix, water-based paints are made by mixing them into an emulsion. This emulsified water-based paint causes a state of pulling a thread when a mechanical shear (shearing force) is applied.

  Moreover, the conventional solvent-type paint has a low viscosity and is atomized finely at the moment of being sprayed (discharged). Furthermore, since the organic solvent volatilizes to some extent until the conventional solvent-type paint adheres to the object to be coated, there is no occurrence of sagging on the coated surface and a uniform cosmetic finish can be achieved. However, pollution-resistant paints such as water-based paints and high solid paints have a high viscosity and are extremely inferior in atomization of mist even when compared with solvent-type paints. Furthermore, there is little volatilization of the diluent during the period from the spraying state to adhesion to the paint surface, which is a factor that causes appearance defects such as repellency and sagging in an actual paint line.

  Conventionally, as a measure for preventing such appearance defects, an additive (non-tackiness) has been added to the paint. However, by adding this additive, Accumulation in pollution-type paint increases. As a result, the accumulation property becomes high, so that the paint (fluid) becomes difficult to flow when pressure fluctuation occurs in the pressure delivered by the paint, or the viscosity of the paint stays and the paint flow becomes stagnant. There is a problem.

  In the pump device 12 according to the present embodiment, for example, a two-component paint (a main agent and a curing agent) of a pollution-resistant paint can be continuously and stably supplied at a desired mixing ratio and discharge amount. As a result, in the pump device 12 according to the present embodiment, the pulsation of the paint (fluid) can be prevented, and the difficulty in staying and flowing of the paint can be suitably avoided.

  That is, the first pump device 12a for supplying the main agent and the second pump device 12b for supplying the curing agent are provided, respectively, and the reciprocating mechanism for reciprocating the outer piston 56 around its axis and the reciprocating motion in the axial direction. By providing the moving mechanism, the suction and discharge (delivery) of the paint can be performed simultaneously, and the paint is not interrupted during the discharge of the paint. Since the paint is not cut off, only the required amount of paint is filled in the pump device 12, so that the size and weight can be reduced, the installation space can be reduced, and mounting on a robot arm (not shown) can be achieved.

  Therefore, in the prior art, it is not necessary to install a pump device in the immediate vicinity of spraying on the object to be coated, and (use amount + α) in one shot of the pump is not required, and paint loss is suppressed and paint use efficiency is improved. Can do. As a result, in an actual line that handles a large number of paint colors, the cleaning time can be shortened when the paint color is repainted, the amount of waste paint can be reduced, and the production efficiency can be greatly improved. .

  Further, by providing a piston stroke speed control device (not shown) that controls the stroke speed of the outer piston 56, the amount of paint delivered from the delivery port 52 can be controlled with high accuracy. In a painting line (one-component paint use line) that requires management of the discharge amount to the object to be coated, it is possible to contribute to improvement and improvement in painting quality, painting productivity, painting cost, and the like.

  Furthermore, in this embodiment, by forming the outer piston 56, the inner piston 66, the shielding member 72, and the receiving member 74 with a ceramic material, it is possible to improve wear resistance and chemical resistance. For example, by forming the shaft-side member with zirconia ceramics and the receiving-side member with alumina ceramics, it is possible to eliminate a leak due to mechanical wear and ensure a fixed amount of discharge. For example, by forming the member to be provided in other wetted parts with polymethylpentene (PMP), it has excellent solvent resistance, workability, wear resistance, drop and impact deformation, and low specific gravity. Weight reduction can be achieved.

  This polymethylpentene has high electrical insulation compared to other resin materials, and is suitable for electrostatic coating (internal application method) of water-based paints. Moreover, by using polymethylpentene, the external fitting of the pump main body 32 of the pump apparatus 12 is made colorless and transparent, and the paint in the pump main body 32 can be easily visually recognized from the outside.

Next, workability when changing the color of the paint will be described.
The waste liquid paint at the time of color change of the paint becomes a capacity remaining in the Y1 site in FIG. 1 and the Y2 site in FIG. The reason why the capacity of the waste paint can be reduced will be described below.

1) By simplifying the structure of the pump device 12, it can be easily and easily cleaned, and the cleanability can be improved.
2) By setting the volume of the chamber 62 of the pump main body 32 to be small, it is possible to suppress the amount of accumulation that remains in the pump main body 32 and becomes a liquid pool.
3) The pump device 12 should be small and light, and can be installed at a position close to the object to be coated, for example, by being mounted on the tip of a robot arm (not shown).
4) The piping structure connected to the pump device 12 can be simplified by providing the single suction port 48 through which the paint is introduced and the single delivery port 52 through which the paint is led out.
5) By forming the pump main body 32 from a resin material, the surface tension can be reduced and the paint can be prevented from sticking to the inner wall of the pump main body 32.
6) By providing the pump body 32 with a transparent or translucent resin material, the paint filled in the pump body 32 is provided so as to be visible.

  Conventionally, the cleaning time of the pump main body 32 and the Y1 and Y2 parts when changing the paint color is set according to the selected paint color by selecting the paint color with the worst washability from the colors to be painted. It had been. In this case, the cleaning time was set uniformly even though the cleaning property was superior or inferior due to the characteristics of the paint (liquid).

  In the present embodiment, the color of the paint remaining in the pump body 32 can be determined by forming the pump body 32 from a transparent resin material and providing the pump body 32 with a color determination sensor (not shown). Thereby, the cleaning time can be selected for each coating color. This is because a coating color having excellent cleaning properties can reduce the cleaning time and the amount of paint waste liquid.

  FIG. 10 is a circuit configuration diagram of a paint supply system according to a modified example in which the pump device according to the embodiment of the present invention is incorporated. In the paint supply system 10 shown in FIG. 1, a paint in which two liquids (main agent and curing agent) are mixed is applied from a coating gun 14 using two pump devices including a first pump device 12 a and a second pump device 12 b. Although it is configured to discharge toward the coated object, for example, like the paint supply system 10a according to the modified example of FIG. 10, the paint sent from the single pump device 12a (b) is applied to the paint gun 14. Alternatively, the liquid may be discharged toward the object to be coated. In FIG. 10, the same components as those shown in FIG. 1 are denoted by the same reference numerals.

10, 10a Paint supply system 12a, 12b, 12 Pump device 32 Pump body (cylinder body)
34 Rotating drum (rotating mechanism)
36 Motor (rotating mechanism)
42 Cylinder tube (cylinder body)
43 Cleaning port block 45 Brush member 46 End block (Cylinder body)
47 Cleaning chamber 48 Suction port 52 Delivery port 56 Outer piston 58 Piston rod 62a First chamber 62b Second chamber 66 Inner piston 68 Notch (communication means)
70 Paint communication channel (communication means, communication channel)
71 Notch space (shielding means)
72 Shielding member (shielding means)
84 Inclined cylinder (reciprocating mechanism)

Claims (4)

A cylinder body provided with a suction port through which a fluid is introduced and a delivery port through which the fluid is derived;
An outer piston and a piston rod slidably provided in the cylinder body;
An inner piston fixed in the cylinder body;
A rotation mechanism for rotating the outer piston around the axis of the piston rod;
A reciprocating mechanism for reciprocating the outer piston along the axial direction of the piston rod;
Communication means provided on the outer piston and communicating between the first chamber and the second chamber in the cylinder body divided by the outer piston;
Shielding means provided on the piston rod of the outer piston and rotating in the circumferential direction integrally with the outer piston, reciprocating along the axial direction of the piston rod, and closing the suction port;
With
The shielding means opens the suction port only at an intermediate position where the outer piston is displaced from one end portion along the axial direction of the cylinder body toward the other end portion, and the outer piston is opened from the one end portion to the other end. The suction port is closed when in a position other than the intermediate position that is displaced toward the part,
The communication means is in a communication state in which the first chamber and the second chamber communicate with each other only at an intermediate position where the outer piston is displaced from the other end along the axial direction of the cylinder body toward the one end. When the outer piston is at a position other than the intermediate position that is displaced from the other end portion toward the one end portion, the communication state between the first chamber and the second chamber is blocked by the inner piston ,
The first chamber is provided so as to communicate with the suction port, the second chamber is provided so as to communicate with the delivery port, and the volume of the first chamber is set larger than the volume of the second chamber. , pump apparatus excess fluid corresponding to the volume difference of the fluid flowing into the second chamber from said first chamber and said Rukoto derived from the delivery port. The pump device according to claim 1, wherein
The shielding means includes a shielding member externally fitted to the piston rod of the outer piston, and the shielding member is formed of a substantially cylindrical body having a notch space portion formed in a fan shape in plan view, The outer piston is set so that the notch space portion of the shielding member is in a rotational position facing the suction port at an intermediate position where the outer piston is displaced from one end portion along the axial direction of the cylinder body toward the other end portion. A pump device characterized by that. The pump device according to claim 1, wherein
Said communication means includes a communication passage formed in the outer piston, said and a cutout portion formed in the inner piston, one end from the outer piston and the other end portion along the axial direction of the cylinder body The pump device, wherein the communication flow path is set at a rotation position facing the notch portion of the inner piston at an intermediate position displaced toward the portion. The pump device according to claim 1, wherein
The cleaning port block is connected to the cylinder body and provided with a cleaning chamber therein. By introducing a cleaning agent into the cleaning chamber, the piston rod of the outer piston is axially cleaned, and the cleaning port block Is provided with an annular brush member that is in sliding contact with the outer peripheral surface of the piston rod.

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