Sealing method

Abstract

To provide a sealing method which is effective for sealing an opening of a workpiece easily.SOLUTION: In a sealing method, a resin sealant S, having fluidity at normal temperature and stationary viscosity for retaining a shape after application at normal temperature, is used. In a state that the sealant S is continuously discharged from a discharge nozzle 10 to adhere to a workpiece 3, the discharge nozzle 10 is moved relative to the workpiece 3 in a feeding direction A in which the discharge nozzle 10 traverses an opening 4 with discharge of the sealant S continued to seal the opening 4 with the sealant S.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a technique for sealing an opening in a workpiece. [Background technology]

[0002] Workpieces such as automobile bodies have various openings, such as openings for removing electrocoating paint and openings used for positioning components for welding. In order to prevent rainwater, dust, noise, and the like from entering through these openings, elastically deformable sealing parts made of resin materials, rubber materials, and the like are used. The openings are sealed by pushing and fitting these sealing parts into the openings of the workpiece. Such sealing parts are generally called "plugs."

[0003] In addition, the following Patent Document 1 discloses a sealing method in which a sealant containing a foaming agent is embedded in an opening hole and the sealant is foamed to close the opening hole. This sealing method has the advantage that it is not necessary to prepare multiple types of plugs in advance to match different sizes of opening holes, and the component cost of the plug can be reduced. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 61-263827 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the above sealing method is adopted, the worker must reach out to each opening while holding the sealing material and manually fill the opening with the sealing material. This can cause a problem that the burden on the worker is heavy. In particular, this problem becomes more pronounced when a large number of openings are provided on the body of an automobile, and the worker must repeatedly take the same posture.

[0006] The present invention has been made in view of the above problems, and aims to provide an effective sealing method for simply sealing an opening in a workpiece. [Means for solving the problem]

[0007] One aspect of the present invention is A method for sealing an opening of a workpiece, comprising the steps of: A resin-based sealant is used that has fluidity at room temperature and a static viscosity that allows it to retain its shape after application at room temperature. A discharge nozzle is disposed on the lower surface side of the workpiece and facing upward at a distance, The above sealant the above a sealing method comprising: continuously discharging the sealant from a discharge nozzle and adhering the sealant to the workpiece; and moving the discharge nozzle in a feed direction across the opening relative to the workpiece while continuing to discharge the sealant, thereby sealing the opening; is located. Effect of the Invention

[0008] In the sealing method of the above-mentioned embodiment, a resin-based sealant is used to seal the opening of the workpiece. This sealant has fluidity at room temperature and a static viscosity for maintaining the shape after application at room temperature. This sealant is continuously discharged from the discharge nozzle and attached to the workpiece, and the discharge nozzle is moved in a feed direction across the opening relative to the workpiece. At this time, by continuing to discharge the sealant from the discharge nozzle, the sealant can be continuously extended from the initial attachment point to block the opening of the workpiece, and the sealant can be attached to the opening of the workpiece and its surrounding area.

[0009] Here, the sealant has a static viscosity that allows it to maintain its shape after application at room temperature, so the sealant is unlikely to peel off or drip off the workpiece even when subjected to the effects of gravity, vibration, etc. Therefore, the opening of the workpiece can be sealed with the sealant and the sealed state can be maintained.

[0010] By discharging the sealant from the discharge nozzle, the worker can perform the sealing work without reaching out to the opening of the work, which reduces the burden on the worker. In addition, by changing the discharge conditions of the sealant, it is possible to perform the sealing work according to the position, size, shape, etc. of the opening in the work. Furthermore, since it is not necessary to prepare and use a sealing part such as a plug for each type of opening, multiple types of sealing parts are not required, and the part cost of the sealing parts can be reduced.

[0011] As described above, according to the above-mentioned aspect, it is possible to provide a sealing method that is effective for simply sealing an opening in a workpiece. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a side view showing the overall configuration of the sealing equipment according to the present embodiment. [Diagram 2] FIG. 4 is a diagram for explaining the thixotropy characteristic of a sealing agent. [Diagram 3] FIG. 2 is a perspective view of the discharge nozzle in FIG. 1, as viewed from the discharge port side. [Figure 4] 3 is a flowchart of a sealing method according to the present embodiment. [Diagram 5] 11A and 11B are diagrams for explaining the discharge trajectory of the sealant when the position of the discharge nozzle is fixed. [Figure 6] 11A and 11B are diagrams for explaining a discharge trajectory of a sealant when a discharge nozzle is moved in a feed direction. [Figure 7] 13 is a diagram showing a state in which the sealant discharged from the discharge nozzle adheres to a workpiece. FIG. [Figure 8] 8 is a diagram showing a state in which the opening of the workpiece is sealed by continuing to discharge the sealant from the discharge nozzle in FIG. 7. [Figure 9] A diagram showing how multiple openings in a workpiece are sealed at once using a single discharge nozzle. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Preferred embodiments of the above aspects are described below.

[0014] In the sealing method of the above-mentioned embodiment, the sealant has a shear rate of 4.2 s, which corresponds to the static viscosity at room temperature. -1 It is preferable that the viscosity at this time is 120 [Pa.s] or more.

[0015] This sealing method exhibits excellent shape retention after application of the sealant. Shear rate: 4.2 s -1 The sealant having a viscosity of 120 [Pa.s] or more at the time of application further has thixotropy, which makes it possible to use a versatile and inexpensive pump to discharge the sealant, thereby making it possible to keep the cost of the sealing equipment required to carry out the sealing method low.

[0016] In the sealing method of the above-mentioned aspect, the discharge nozzle is a wide nozzle having a discharge outlet whose nozzle height is equivalent to or less than the target set film thickness and whose nozzle width is equal to or greater than the opening diameter, and which discharges the sealant in a band-like shape from the discharge outlet, and it is preferable that the feed direction of the upper discharge nozzle is a direction along the nozzle height of the wide nozzle.

[0017] According to this sealing method, the nozzle height of the wide nozzle corresponds to the thickness of the belt-like sealant after it is discharged, so it is effective in controlling the seal thickness of the opening of the workpiece to be roughly constant. In this case, the sealant can be attached evenly to the opening of the workpiece and its surroundings without being diffused, which is effective in improving the sealing performance of the opening.

[0018] In the sealing method according to the above aspect, it is preferable that the discharge nozzle is moved in the feed direction while being inclined with respect to an opening plane of the opening.

[0019] According to this sealing method, by moving the discharge nozzle at an angle relative to the opening plane of the opening of the work, it becomes easy to adjust the supply balance when the sealant is applied to the work.

[0020] In the sealing method of the above aspect, when a plurality of the openings are linearly arranged at intervals in the workpiece, it is preferable that the arrangement direction of the plurality of the openings is the feed direction of the discharge nozzle.

[0021] According to this sealing method, by moving the discharge nozzle in the direction of arrangement of the multiple openings provided in the workpiece, it is possible to seal multiple openings in the workpiece at once by simply moving the discharge nozzle in one direction. Also, when the sealant is discharged for each opening, it is possible to save sealant.

[0022] The sealing method of the above aspect includes a preparation step of setting in advance a discharge condition of the sealant and a moving speed of the discharge nozzle in the feed direction; a sealing step of moving the discharge nozzle in the feed direction at the moving speed set in the preparation step while continuously discharging the sealant from the discharge nozzle toward the workpiece under the discharge condition set in the preparation step; having The discharge condition is preferably at least one of a distance between the workpiece and a discharge port of the discharge nozzle, a discharge flow rate of the sealant, and a discharge speed of the sealant.

[0023] According to this sealing method, in the preparation step, the discharge conditions of the sealant and the moving speed of the discharge nozzle in the feed direction are set in advance. Then, in the subsequent sealing step, the discharge nozzle is moved in the feed direction while actually discharging the sealant from the discharge nozzle toward the workpiece using the discharge conditions and moving speed set in the preparation step. By performing the preparation step in advance and setting the conditions in advance, it is possible to prevent defects such as poor sealing of the opening in the subsequent sealing step.

[0024] In the sealing method of the above aspect, it is preferable that the discharge nozzle is held by a robot arm, and the robot arm is controlled so that the discharge nozzle moves in the feed direction when the sealant is discharged.

[0025] According to this sealing method, by controlling the robot arm to move the discharge nozzle in the feed direction, it is possible to automate and speed up the sealing work of the opening of the workpiece. Automation eliminates the need for the worker to perform the sealing work in a posture that places a heavy burden on the worker.

[0026] Hereinafter, an embodiment of a technique for sealing an opening provided in a workpiece, which is an automobile body, will be described with reference to the drawings.

[0027] In the drawings for explaining this embodiment, unless otherwise specified, a first direction, which is the horizontal direction, is indicated by an arrow X, and a second direction, which is the up-down direction perpendicular to the first direction, is indicated by an arrow Y.

[0028] 1, the sealing equipment 1 according to this embodiment is for sealing an opening 4 formed in a horizontal surface of a workpiece 3 constituting a vehicle body 2. Here, the workpiece 3 is typically a base material such as a member or reinforcement constituting an underbody of the vehicle body 2.

[0029] The workpiece 3 extends generally horizontally in the first direction X. The opening 4 provided in the workpiece 3 typically includes an opening hole, a through hole, a recess, etc. In this embodiment, the opening 4 is exemplified by a through hole (opening diameter d) having a circular shape in a plan view.

[0030] The sealing equipment 1 includes a discharge nozzle 10 , a pump 11 , a supply pipe 12 , a robot 20 , and a control device 30 .

[0031] The discharge nozzle 10 is connected to a pump 11 via a supply pipe 12. The pump 11 is configured to pressurize and discharge a flowable resin-based sealant S. The sealant S discharged by the pump 11 is pumped through the supply pipe 12 to the discharge nozzle 10 and is discharged to the outside from a discharge port 10a of the discharge nozzle 10.

[0032] The discharge nozzle 10 is held at an arm tip 22 of a robot arm 21 of a robot 20. The robot 20 is configured as a multi-axis robot in which a plurality of drive axes are provided on the robot arm 21. Both the robot 20 and the pump 11 are electrically connected to a control device 30.

[0033] The control device 30 is configured with a known CPU, a memory, an input / output unit, etc. The control device 30 includes a robot control unit 31 and a pump control unit 32.

[0034] The robot control unit 31 has a function of controlling the robot 20. The robot control unit 31 controls the robot 20 so that the arm tip 22 of the robot arm 21 moves according to a movement trajectory taught in advance. This allows the discharge nozzle 10 to be adjusted to a desired posture.

[0035] The pump control unit 32 has a function of controlling the pump 11. The pump control unit 32 controls the discharge flow rate of the sealant S discharged from the discharge nozzle 10 (the pressure and speed from the nozzle opening vary depending on the flow rate control).

[0036] Sealant S is a resin (e.g., vinyl chloride resin)-based sealant that has fluidity at room temperature and has a static viscosity to maintain its shape after application at room temperature. This sealant S has a shear rate of 4.2 s, which is equivalent to the static viscosity at room temperature. -1 It is preferable that the viscosity at room temperature is 120 [Pa.s] or more. Furthermore, it is preferable that the sealing agent S has thixotropy to improve the fluidity at room temperature. The "room temperature" here is typically a temperature within the range of 20 to 30 [°C].

[0037] 2, the "thixotropic property" of the sealant S refers to the property that the viscosity decreases with decreasing shear rate. According to such thixotropic property, the viscosity of the sealant S decreases in a region where the shear rate of the sealant S is relatively high, while the viscosity of the sealant S increases in a region where the shear rate of the sealant S is relatively low.

[0038] In the case where the sealant S has thixotropic properties, when the sealant S is discharged from the discharge nozzle 10, the discharge pressure from the pump 11 causes the sealant S in the discharge nozzle 10 to flow, increasing the shear rate of the sealant S. At this time, the viscosity of the sealant S having thixotropic properties temporarily decreases, so that a constant level of fluidity of the sealant S can be maintained. Therefore, the discharge performance of the sealant S in the discharge nozzle 10 can be improved.

[0039] When the sealant S having thixotropy is discharged from the discharge nozzle 10 and adheres to the workpiece 3, no external force acts on the sealant S, so the shear rate of the sealant S is lower than when it was discharged. At this time, the viscosity of the sealant S having thixotropy increases, so the desired adhesion performance and shape retention performance of the sealant S can be ensured. In other words, the sealant S once adhered to the workpiece 3 is less likely to peel off or drip off the workpiece 3.

[0040] 3, the discharge nozzle 10 is configured so that the nozzle height h of the discharge port 10a in the nozzle height direction D1 is equivalent to or less than the target set film thickness, and the nozzle width w of the discharge port 10a in the nozzle width direction D2 is equal to or greater than the opening diameter d (see FIG. 1) of the opening 4. That is, the discharge nozzle 10 is a wide nozzle that discharges the sealant S in a strip-like shape from the horizontally long discharge port 10a in the discharge direction B. For this reason, for example, when the discharge port 10a of the discharge nozzle 10 is disposed facing upward, the strip-like sealant S continuously discharged from the discharge port 10a is curved so that the discharge tip side hangs down due to the effect of gravity.

[0041] Although the value of the opening diameter d of the opening 4 is not particularly limited, a typical vehicle body 2 is provided with a relatively large number of openings 4 with opening diameters d ranging from φ10 to φ25, including openings 4 with opening diameters d of about φ10. The nozzle width w of the discharge port 10a of the discharge nozzle 10 is determined according to the opening diameter d of the target opening 4.

[0042] The opening 4 may have a shape other than a circle in a plan view (for example, an ellipse, a polygon, etc.). In this case, the opening diameter d is interpreted as the maximum opening diameter of the opening 4, and the discharge nozzle 10 can be configured so that the discharge port 10a has a nozzle height h equivalent to or less than the target set film thickness and a nozzle width w equal to or greater than the maximum opening diameter.

[0043] Next, a sealing method for sealing the opening 4 of the work 3 using the sealing equipment 1 having the above configuration will be described with reference to Figs. 1 and 4 to 9.

[0044] 1, when the sealing equipment 1 is used, a control signal is output from a robot control unit 31 of a control device 30 to the robot 20 to adjust the posture of the robot arm 21. This allows the discharge nozzle 10 to approach the workpiece 3 from below. The discharge nozzle 10 is disposed facing upward so that its discharge port 10a faces the peripheral area of ​​the opening 4 of the workpiece 3.

[0045] As shown in FIG. 4, the sealing method of the present embodiment includes a preparation step S101 and a sealing step S102.

[0046] The preparation step S101 is a step for setting in advance the discharge conditions of the sealant S and the moving speed V of the discharge nozzle 10 in the feed direction A. As shown in Fig. 5, in this preparation step S101, the sealant S is not discharged toward the actual workpiece 3, but a test is performed in which the sealant S is discharged toward a virtual workpiece 3A (which does not actually exist) on the assumption that the workpiece 3 is present.

[0047] In this test, the discharge nozzle 10 is arranged so that its discharge port 10a faces upward, and the discharge nozzle 10 is tilted with respect to the opening plane C of the opening 4. At this time, it is preferable to tilt the discharge nozzle 10 so that the discharge angle α of the discharge direction B of the sealant S with respect to the opening plane C is within a range of approximately 70° to 90°.

[0048] Here, as shown in FIG. 5, the discharge nozzle 10 is not moved and the position is fixed, and the sealant S is actually discharged from the discharge nozzle 10 to verify the discharge trajectory T of the sealant S. At this time, the distance between the apex Ta of the discharge trajectory T and the upper surface of the virtual workpiece 3A is defined as the correction distance E. The sealant S discharged from the discharge nozzle 10 forms the discharge trajectory T based on the balance between the upward discharge pressure and the gravity acting downward. Therefore, the discharge trajectory T is determined by the discharge angle α of the discharge nozzle 10, the separation distance F between the workpiece 3 and the discharge port 10a of the discharge nozzle 10, and the discharge flow rate Q of the sealant S (or the discharge speed of the sealant S). In addition, when discharging downward or discharging sideways, the discharge trajectory T can be determined by correcting the gravity.

[0049] Therefore, in this example, the separation distance F and the discharge flow rate Q are variously changed while the discharge angle α of the discharge nozzle 10 is fixed, and the separation distance F and the discharge flow rate Q are obtained when the correction distance E approximately coincides with a preset initial value. The separation distance F and the discharge flow rate Q thus obtained are then used in the sealing step S102. If necessary, the discharge speed may be used instead of the discharge flow rate Q.

[0050] 6, when the discharge nozzle 10 is moved in the feed direction A, the discharge trajectory T of the sealant S when the position of the discharge nozzle 10 is fixed changes to a discharge trajectory T' due to the effect of moving the discharge nozzle 10. That is, the position of the apex Ta of the discharge trajectory T moves down to the position of the apex Ta of the discharge trajectory T'. If such a discharge trajectory T' of the sealant S can be formed, the sealant S can be discharged from the discharge port 10a of the discharge nozzle 10 with a minimum force that does not cause the sealant S to break through the opening 4.

[0051] Therefore, in this example, the moving speed V of the discharge nozzle 10 in the feed direction A is calculated when the correction distance E (see FIG. 5) becomes approximately zero (i.e., the position of the apex Ta of the discharge trajectory T' approximately coincides with the upper surface of the workpiece 3). Then, the moving speed V calculated in this way is used in the sealing step S102.

[0052] The sealing step S102 is a step for sealing the opening 4 of the actual workpiece 3 after the preparation step S101. In this sealing step S102, the discharge nozzle 10 is held by the robot arm 21 of the robot 20, and the robot arm 21 is controlled so that the discharge nozzle 10 moves in the feed direction A when the sealant S is discharged.

[0053] As in the preparation step S101, the discharge nozzle 10 is arranged so that its discharge port 10a faces upward, and is tilted with respect to the opening plane C of the opening 4. The direction along the nozzle height h (see FIG. 3) of the discharge nozzle 10, which is a wide nozzle, is defined as the feed direction A of the discharge nozzle 10.

[0054] 7, in the sealing step S102, first, the sealant S is continuously discharged from the discharge nozzle 10 in an upward orientation at the first position P1 to adhere to the peripheral portion of the opening 4 of the workpiece 3. The adhesion point of the sealant S at this time becomes the initial adhesion point Sa.

[0055] 8, with the sealant S attached to the workpiece 3, the inclined discharge nozzle 10 is moved in a feed direction A across the opening 4 relative to the workpiece 3 while continuing to discharge the sealant S. That is, the discharge nozzle 10 is moved in the feed direction A from a first position P1 to a second position P2. This allows the sealant S extending from the initial attachment point Sa to block the opening 4 of the workpiece 3 and seal it with resin.

[0056] The sealant S forms a blocking portion Sb having a thickness according to the shape of the discharge port 10a of the discharge nozzle 10. The shape of the blocking portion Sb is formed in a slightly pressed-in state by the thickness of the sealant S discharged from the discharge port 10a of the discharge nozzle 10, the maximum opening diameter of the opening 4, and the discharge pressure for ensuring application reliability. Therefore, in the region of the blocking portion Sb, the sealant S tends to form a sealing layer that is slightly thinner than the initial adhesion point Sa due to the pressing in of the sealant S.

[0057] At this time, by using the separation distance F, discharge flow rate Q, and movement speed V previously determined in the preparation step S101 in the sealing step S102, it becomes possible to easily seal the opening 4 with the sealant S without taking measures such as placing a separate member such as a backing plate on the other side (top side) of the opening 4 of the workpiece 3 to prevent the sealant S from penetrating through the opening.

[0058] As shown in Fig. 9, a plurality of openings 4 provided in the workpiece 3 can be sealed continuously. Here, the plurality of openings 4 includes a first opening 4A, a second opening 4B, and a third opening 4C. The three openings 4A, 4B, and 4C are linearly arranged at intervals from each other. Therefore, the arrangement direction of the three openings 4A, 4B, and 4C is set as the feed direction A of the discharge nozzle 10.

[0059] When sealing a plurality of openings 4 consecutively, the discharge nozzle 10 is moved in the feed direction A from the first position P1, through the second position P2 and the third position P3 in sequence, to the fourth position P4 at a constant moving speed V. When the discharge nozzle 10 reaches the second position P2, the first opening 4A is sealed with the sealant S. When the discharge nozzle 10 subsequently reaches the third position P3, the second opening 4B is sealed with the sealant S. Finally, when the discharge nozzle 10 reaches the fourth position P4, the remaining third opening 4C is also sealed with the sealant S.

[0060] In this way, by moving the discharge nozzle 10 in the arrangement direction of the multiple openings 4 provided in the workpiece 3, it becomes possible to seal the multiple openings 4 of the workpiece 3 at once by simply moving one discharge nozzle 10 in one direction. Furthermore, when the sealant S is discharged for each opening 4, it is possible to save the sealant S.

[0061] The number of openings 4 is not limited to three, and may be a number other than three as necessary. Also, the multiple openings 4 may be individually sealed by the discharge nozzle 10 at the respective timings.

[0062] According to the above-described embodiment, the following advantageous effects can be obtained.

[0063] In the sealing method of this embodiment, a resin-based sealant S is used to seal the opening 4 of the workpiece 3. As described above, the sealant S is sufficient as long as it has fluidity at room temperature and has a static viscosity to maintain the shape after application at room temperature. The sealant S is continuously discharged from the discharge nozzle 10 and attached to the workpiece 3, and the discharge nozzle 10 is moved in a feed direction A crossing the opening 4 relative to the workpiece 3. At this time, by continuing to discharge the sealant S from the discharge nozzle 10, the sealant S can be continuously extended from the initial attachment point Sa to block the opening 4 of the workpiece 3, and the sealant S can be attached to the opening 4 of the workpiece 3 and its surrounding area.

[0064] Here, if the sealant S further has thixotropy, the shear rate temporarily increases and the viscosity decreases when the sealant S is discharged from the discharge nozzle 10. At this time, the fluidity of the sealant S temporarily increases, so that the sealant S discharged from the discharge nozzle 10 can be easily attached to the workpiece 3. On the other hand, after the sealant S is attached to the workpiece 3, the shear rate decreases compared to when it was discharged, and the viscosity increases. At this time, the fluidity of the sealant S attached to the workpiece 3 decreases according to its viscosity, so that the shape retention performance is improved, and the sealant S is unlikely to peel off or drip from the workpiece 3 even if it is affected by gravity, vibration, or the like. Therefore, the opening 4 of the workpiece 3 can be sealed with the sealant S, and the sealed state can be maintained.

[0065] By discharging the sealant S from the discharge nozzle 10, the worker can perform the sealing work without reaching out to the opening 4 of the workpiece 3, reducing the burden on the worker. In addition, by changing the discharge conditions of the sealant S, it is possible to perform the sealing work according to the position, size, shape, etc. of the opening 4 in the workpiece 3. The sealing work can be performed without being affected even if the workpiece 3 has unevenness. Furthermore, since there is no need to prepare and use sealing parts such as plugs for each type of opening 4, multiple types of sealing parts are not required, and the part cost of the sealing parts can be reduced.

[0066] Therefore, a sealing method that is effective for simply sealing the opening 4 of the workpiece 3 can be provided.

[0067] According to the sealing method of the present embodiment, an excellent effect is exhibited with respect to shape retention after application of the sealant. -1 When the sealant has a viscosity of 120 [Pa.s] or more at the time of injection and further has thixotropy, it becomes possible to use a versatile and inexpensive pump 11 to discharge the sealant S. This makes it possible to keep the cost required for the sealing equipment 1 for carrying out the sealing method low.

[0068] According to the sealing method of the present embodiment, the nozzle height h of the discharge nozzle 10, which is a wide nozzle, corresponds to the thickness of the belt-like sealant S after discharge, and is therefore effective in controlling the seal thickness of the opening 4 of the workpiece 3 to be generally constant. At this time, the sealant S can be attached evenly to the opening 4 of the workpiece 3 and its surroundings without being diffused, which is effective in improving the sealing performance of the opening 4.

[0069] According to the sealing method of the present embodiment, by moving the discharge nozzle 10 at an angle relative to the opening plane C of the opening 4 of the workpiece 3, it becomes easy to adjust the supply balance when the sealant S is applied to the workpiece 3.

[0070] According to the sealing method of this embodiment, in the preparation step S101, the discharge conditions of the sealant S and the moving speed V of the discharge nozzle 10 in the feed direction A are set in advance. Then, in the subsequent sealing step S102, the discharge nozzle 10 is moved in the feed direction A while actually discharging the sealant S from the discharge nozzle 10 toward the workpiece 3 using the discharge conditions (the separation distance F between the workpiece 3 and the discharge port 10a of the discharge nozzle 10, the discharge flow rate Q of the sealant S) and the moving speed V set in the preparation step S101. By performing the preparation step S101 in advance and setting the conditions in advance, it is possible to prevent defects such as poor sealing of the opening 4 from occurring in the subsequent sealing step S102.

[0071] When the sealant S is applied to the workpiece 3 in a wavy shape due to an oversupply of the sealant S, it is preferable to reduce the discharge flow rate Q of the sealant S or to increase the moving speed V of the discharge nozzle 10. When the sealant S is applied to the workpiece 3 in a thinner shape than expected due to an undersupply of the sealant S, it is preferable to increase the discharge flow rate Q of the sealant S or to decrease the moving speed V of the discharge nozzle 10. This allows the thickness of the sealant S applied to the workpiece 3 to be adjusted to be approximately constant.

[0072] According to the sealing method of the present embodiment, it is possible to automate and speed up the sealing operation of the opening 4 of the workpiece 3 by controlling the robot arm 21 of the robot 20 to move the discharge nozzle 10 in the feed direction A. This automation makes it possible to eliminate the need for the worker to perform the sealing operation in a posture that places a great burden on the worker.

[0073] The present invention is not limited to the exemplary embodiment described above, and various applications and modifications are possible without departing from the scope of the present invention. For example, the following embodiments can be implemented by applying the above-described embodiment.

[0074] In the above embodiment, the case where the discharge nozzle 10 is moved in the feed direction A by using the robot arm 21 has been exemplified, but instead of this, a drive device that slides the discharge nozzle 10 along a slide rail (not shown) in the feed direction A can also be adopted. Also, if necessary, the worker may hold the discharge nozzle 10 with his / her fingers and move it in the feed direction A.

[0075] In the above embodiment, the case where the sealant S is discharged upward from the lower surface side of the workpiece 3 extending in the horizontal direction by the upward discharge nozzle 10 is illustrated. In reference form It is also possible to adopt a structure in which the sealant S is ejected downward from a downward ejection nozzle 10 from the top surface side of the workpiece 3 extending in the horizontal direction, or a structure in which the sealant S is ejected sideways from a horizontal ejection nozzle 10 from the side surface side of the workpiece extending in the vertical direction.

[0076] In the above-described embodiment, an example was given of using a wide nozzle having a horizontally elongated outlet 10a as the outlet nozzle 10, but the shape of the outlet 10a is not limited to this, and the shape of the outlet 10a can be appropriately changed as necessary.

[0077] In the above embodiment, an example was given of the case where the discharge nozzle 10 is moved in the feed direction A while being inclined with respect to the opening plane C of the opening 4. However, if necessary, the discharge nozzle 10 may be moved in the feed direction A while being positioned perpendicular to the opening plane C of the opening 4 (the inclination angle α in Figure 5 is approximately 90°).

[0078] In the above-described embodiment, a technology for sealing the opening 4 of the workpiece 3 constituting the underbody of the vehicle body 2 with sealant S has been exemplified, but the sealing location is not limited to this, and this technology can also be applied to a technology for sealing the opening of a part constituting an element of the vehicle body 2 other than the underbody with sealant S, or a technology for sealing the opening provided in a part constituting an object other than an automobile with sealant S. [Explanation of symbols]

[0079] 3 Work 4,4A,4B,4C opening 10 Discharge nozzle 10a outlet 21 Robot Arm A Feed direction C aperture plane d Opening diameter E Correction Distance F Separation distance h Nozzle height Q Discharge flow rate S Sealant T,T' Discharge trajectory Ta vertex V Movement speed w Nozzle width α Discharge angle

Claims

1. A sealing method for sealing an opening of a workpiece, comprising: using a resin-based sealant that has fluidity at room temperature and a standing viscosity for maintaining the shape after application at room temperature; placing a discharge nozzle spaced apart from the lower surface side of the workpiece and facing upward, continuously discharging the sealant from the discharge nozzle and attaching it to the workpiece, and moving the discharge nozzle in a feed direction crossing the opening with respect to the workpiece while continuing the discharge of the sealant to seal the opening with the sealant.

2. The sealant has a viscosity equivalent to the static viscosity at normal temperature and has a viscosity of 120 [Pa·s] or more at a shear rate of 4.2 s -１ The sealing method according to claim 1, wherein the viscosity at -１ is 120 [Pa·s] or more at a shear rate of 4.2 s

3. The discharge nozzle has a discharge port where the nozzle height is equivalent to or less than the target set film thickness and the nozzle width is equal to or greater than the opening diameter of the opening, and is a wide nozzle that discharges the sealant in a band shape from the discharge port, and the direction along the nozzle height of the wide nozzle is the feed direction of the discharge nozzle. The sealing method according to Claim 1 or 2.

4. The sealing method according to Claim 3, wherein the discharge nozzle is moved in the feed direction while being inclined with respect to the opening plane of the opening.

5. The sealing method according to Claim 3 or 4, wherein when a plurality of the openings are linearly arranged on the workpiece with a space therebetween, the arrangement direction of the plurality of the openings is the feed direction of the discharge nozzle.

6. A preparation step of presetting the discharge conditions of the sealant and the moving speed of the discharge nozzle in the feed direction; A sealing step of continuously discharging the sealant from the discharge nozzle toward the workpiece under the discharge conditions set in the preparation step while moving the discharge nozzle in the feed direction at the moving speed set in the preparation step; comprising: The discharge conditions are at least one of the separation distance between the workpiece and the discharge port of the discharge nozzle, the discharge flow rate of the sealant, and the discharge speed of the sealant. The sealing method according to any one of Claims 1 to 5.

7. The sealing method according to any one of Claims 1 to 6, wherein the discharge nozzle is held by a robot arm and the robot arm is controlled so that the discharge nozzle moves in the feed direction when the sealant is discharged.

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