Masking jig, and surface treatment method using the same

Abstract

To provide a masking jig capable of preventing air present in recesses from expanding even when recesses are provided on one end face of a surface treatment object, and a surface treatment method using the same.SOLUTION: The masking jig comprises a first fitting section 12 fitting to a bearing 3 and the inner circumferential face of a bush 3a of a movable scroll 1, and a second fitting section 13 fitting to the outer circumferential face of the bearing 3 of the movable scroll 1, and hence the bearing 3 and bush 3a of the movable scroll 1 can be fitted in a manner of being pinched by the first fitting section 12 and the second fitting section 13, and the jig body 11 can firmly be held by the movable scroll 1. Since a space is prevented from forming in each of the recesses 2a by fitting the protrusions 22 of an intermediate member 20 into corresponding recesses 2a of the movable scroll 1, the expansion of air in each of the recesses 2a caused by heat of a high-temperature surface treatment liquid, can be prevented.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a masking tool used when performing surface treatments such as plating and anodizing on parts of various industrial products, and to a surface treatment method using the same. [Background technology]

[0002] In general, when surface treatment is applied to parts of various industrial products, the surface treatment is performed while the portions not to be surface-treated are masked. For example, a movable scroll, which is one component of a scroll-type compressor, has a cylindrical bearing portion protruding from the center of one end face thereof, and the surface treatment is performed on the portions of the movable scroll other than the one end face including the bearing portion. In this case, a dedicated masking jig is attached to the movable scroll, and the portions not to be surface-treated are masked by the masking jig (see, for example, Patent Document 1).

[0003] This masking jig has a jig body formed to cover one end face of the movable scroll, and is provided with a first fitting portion whose outer peripheral surface fits into the inner peripheral surface of the bearing portion of the movable scroll, and a second fitting portion whose inner peripheral surface fits into the outer peripheral surface of the bearing portion.When the jig body is attached to the movable scroll, the first fitting portion and the second fitting portion fit together to sandwich the cylindrical portion, so that the jig body is securely held on the movable scroll. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2023-88432 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, the one end face of the movable scroll may be provided with a recess for mounting other components or for weight reduction, but if such a recess exists, a space is created between the jig body of the masking jig and the one end face of the movable scroll by the recess. As a result, when immersed in a high-temperature liquid for surface treatment, the air in the recess expands significantly due to the heat of the liquid, and the pressure of the expanded air is applied between the one end face of the movable scroll and the jig body. Therefore, the expansion of the air in the recess may cause the jig body to move, causing the masking position to shift, or the sealing performance between the jig body and the movable scroll to decrease, and there was a problem that it was necessary to suppress the expansion of the air in the recess in order to prevent these.

[0006] The present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to provide a masking tool and a surface treatment method using the same that can suppress the expansion of air in a recess even when a recess is provided on one end face of an object to be surface treated. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the present invention provides a masking jig that is attached to a surface treatment object having at least one recess formed on one end face and a cylindrical portion with one open end protruding from the center of the one end face, and that masks the surface treatment object with a jig body formed to cover one end face of the surface treatment object.The masking jig includes an intermediate member that is arranged between the one end face of the surface treatment object and the jig body and has a protrusion that fits into the recess, and the jig body is provided with a first fitting portion whose outer peripheral surface fits with the inner peripheral surface of the cylindrical portion, and a second fitting portion whose inner peripheral surface fits with the outer peripheral surface of the cylindrical portion.

[0008] As a result, when the intermediate member is attached to the surface treatment object and the jig body is attached to the surface treatment object, the outer peripheral surface of the first fitting portion fits into the inner peripheral surface of the cylindrical portion, and the inner peripheral surface of the second fitting portion fits into the outer peripheral surface of the cylindrical portion, so that the first fitting portion and the second fitting portion fit to sandwich the cylindrical portion. In addition, since the convex portion of the intermediate member fits into the concave portion of one end surface of the surface treatment object, no space is generated in the concave portion where the convex portion fits. In this case, since the convex portion is provided on the intermediate member that is separate from the jig body, if the number, position, size, shape, etc. of the concave portions differ depending on the specifications and type of the surface treatment object, it is sufficient to replace the intermediate member with one having a convex portion according to the specifications and type of the surface treatment object. It has the advantage of being highly versatile.

[0009] In addition, in order to achieve the above-mentioned object, the present invention provides a masking jig that is attached to a surface treatment object having at least one recess formed on one end face and a cylindrical portion with one open end protruding from the center of the one end face, and that masks the surface treatment object with a jig body formed to cover one end face of the surface treatment object, the jig body being provided with a protrusion that fits into the recess, a first fitting portion whose outer peripheral surface fits into the inner peripheral surface of the cylindrical portion, and a second fitting portion whose inner peripheral surface fits into the outer peripheral surface of the cylindrical portion.

[0010] As a result, when the jig body is attached to the surface treatment object, the outer peripheral surface of the first fitting portion fits into the inner peripheral surface of the cylindrical portion, and the inner peripheral surface of the second fitting portion fits into the outer peripheral surface of the cylindrical portion, so that the first fitting portion and the second fitting portion fit together to sandwich the cylindrical portion. Also, since the convex portion of the jig body fits into the concave portion of one end face of the surface treatment object, no space is generated in the concave portion where the convex portion fits. In this case, since the convex portion is provided integrally with the jig body, when the jig body is attached to the surface treatment object, the convex portion of the jig body fits into the concave portion of the surface treatment object. Effect of the Invention

[0011] According to the present invention, since the first fitting portion and the second fitting portion can be fitted so as to sandwich the cylindrical portion, the jig body can be reliably held on the surface treatment object, and even if vibration or impact is applied, it is possible to effectively prevent the jig body from falling off from the surface treatment object. Even if a recess is provided on one end surface of the movable scroll, no space is generated in the recess where the protrusion is fitted, so that the expansion of air in the recess due to the heat of the high-temperature liquid for surface treatment can be suppressed. As a result, the positional deviation of the jig body and the deterioration of the sealing property due to the expansion of air in the recess do not occur, so that it is possible to reliably prevent masking failure and infiltration of liquid. In this case, a masking jig having a protrusion provided on an intermediate member separate from the jig body has the advantage of being highly versatile, since it can be replaced with an intermediate member having a protrusion according to the specifications and type of the surface treatment object even if the number, position, size, shape, etc. of the recesses differ depending on the specifications and type of the surface treatment object. In addition, a masking jig having a convex portion integral with the jig body can be quickly attached and detached from the object to be surface-treated, thereby improving workability when performing surface treatment on a large number of objects to be surface-treated that have the same number, position, size, and shape of concave portions. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a plan view of a jig body of a masking jig showing a first embodiment of the present invention; [Diagram 2] Bottom view of the jig body [Diagram 3] Front view of the jig body [Figure 4] Plan view of intermediate part [Diagram 5] Side view of intermediate part [Figure 6] A perspective view of an intermediate member [Figure 7] FIG. 1 is a perspective view of a masking jig and a movable scroll; [Figure 8] Side cross-sectional view showing the masking jig installation process [Figure 9] Side cross-sectional view showing the masking jig attached [Figure 10]Side cross-sectional view showing the masking jig attached [Figure 11] FIG. 11 is a bottom view of a jig body of a masking jig showing a second embodiment of the present invention. [Figure 12] FIG. 1 is a perspective view of a masking jig and a movable scroll; [Figure 13] Side cross-sectional view showing the masking jig installation process [Figure 14] Side cross-sectional view showing the masking jig attached DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] 1 to 10 show a first embodiment of the present invention, and show a masking jig used in a surface treatment process for a movable scroll, which is one component of a scroll-type compressor, for example.

[0014] The movable scroll 1 as the surface treatment object shown in the figure has a cylindrical bearing portion 3 protruding from one end surface of a disk-shaped main body portion 2, and a cylindrical bush 3a attached to the inner peripheral surface of the bearing portion 3, with the bearing portion 3 and the bush 3a forming a cylindrical portion. The inside of the bearing portion 3 is formed deeper than the one end surface of the main body portion 2, and an engagement portion 3b consisting of an annular recess is formed in the gap between one axial end of the bush 3a and the bottom surface of the bearing portion 3. The one end surface of the main body portion 2 is formed flat except for the bearing portion 3, and a plurality of circular recesses 2a for mounting other parts, for example, are provided at intervals in the circumferential direction of the main body portion 2. The number, position, size, shape, etc. of the recesses provided on the one end surface of the main body portion 2 are not limited to the recesses 2a of this embodiment, and may be recesses for weight reduction, for example. A scroll portion 4 is protruding from the other end surface of the main body portion 2, which is radially eccentric, and the inside of the scroll portion 4 is formed in a spiral shape, although not shown.

[0015] The masking jig 10 of this embodiment comprises a jig body 11 formed to cover one end face side of the movable scroll 1, and an intermediate member 20 arranged between the one end face of the movable scroll 1 and the jig body 11, and the jig body 11 is adapted to be attached to the movable scroll 1 in a freely detachable manner.

[0016] The jig body 11 is made of an elastically deformable material such as rubber, and is provided with a first fitting portion 12 that fits into the inner surface of the bearing portion 3 of the movable scroll 1, a second fitting portion 13 that fits into the outer surface of the bearing portion 3 of the movable scroll 1, a third fitting portion 14 that fits into the outer surface of the main body portion 2 of the movable scroll 1, and a gripping portion 15 that can be held with fingers, and the third fitting portion 14 is configured to be pressed against the outer surface of the main body portion 2 of the movable scroll 1 by an elastic ring 16 which is a ring-shaped member.

[0017] The jig body 11 is formed in a disk shape, and a protrusion 11a that protrudes unevenly in one axial direction (the opposite side to the mounting surface to the movable scroll 1) is formed concentrically with the jig body 11 on the radial center side of one end face of the jig body 11. In addition, a recess 11b that is concentric with the jig body 11 is provided on the other end face of the jig body 11 (the mounting surface to the movable scroll 1), and the outer diameter of the recess 11b is formed to be larger than the outer diameter of the protrusion 11a.

[0018] The first fitting portion 12 is provided so as to protrude concentrically with the jig body 11 from the center of the other end surface of the jig body 11 toward the opposite side of the protruding portion 11a, and is formed in a cylindrical shape with an outer diameter equal to the inner diameter of the bush 3a of the bearing portion 3 of the movable scroll 1 and a length slightly shorter than the depth of the inner circumferential side of the bearing portion 3. An engagement portion 12a consisting of an annular protrusion protruding radially outward is formed on the edge on the tip side of the first fitting portion 12, and the engagement portion 12a is adapted to engage with the engagement portion 3b of the movable scroll 1. In addition, a recess 12b concentrically with the jig body 11 is provided on the center of the tip surface of the first fitting portion 12.

[0019] The second fitting portion 13 is provided so as to protrude concentrically from the other end face side of the jig body 11 toward the opposite side of the protruding portion 11a, and is formed in a cylindrical shape with a radial gap from the first fitting portion 12. In this case, the second fitting portion 13 is formed so that the inner diameter dimension is equal to the outer diameter dimension of the bearing portion 3 of the movable scroll 1, and the length dimension is equal to the height dimension of the outer circumferential side of the bearing portion 3. A pressure contact portion 13a consisting of an annular convex portion protruding radially inward is formed on the edge on the tip side of the second fitting portion 13, and the pressure contact portion 13a is configured to be in pressure contact with the outer circumferential surface of the bearing portion 3.

[0020] The third fitting portion 14 is provided so as to protrude concentrically with the jig body 11 from the peripheral edge side of the jig body 11 toward the opposite side of the protruding portion 11a, and is formed in a cylindrical shape whose inner diameter is equal to the outer diameter dimension of the body portion 2 of the movable scroll 1 and whose length dimension is slightly shorter than the height dimension of the outer circumferential side of the body portion 2. In addition, an annular groove portion 14a with which the elastic ring 16 engages is provided on the outer circumferential surface of the third fitting portion 14, and the groove portion 14a is formed in a substantially semicircular cross section.

[0021] The grip portion 15 is provided so as to protrude from the protruding portion 11a in one axial direction, and is formed in a plate shape having two flat surfaces perpendicular to one end face of the protruding portion 11a. The grip portion 15 is also provided with a through hole 15a penetrating through both sides in the thickness direction, and the through hole 15a is adapted to receive a hook (not shown) for hanging.

[0022] The elastic ring 16 is made of a rubber O-ring, and when attached to the groove portion 14a of the third fitting portion 14, it presses the third fitting portion 14 against the outer peripheral surface of the main body portion 2 of the movable scroll 1.

[0023] The intermediate member 20 comprises a flat plate portion 21 formed in a disk shape and a plurality of convex portions 22 which respectively fit into each of the concave portions 2a of the movable scroll 1, and the flat plate portion 21 and each of the convex portions 22 are integrally formed from an elastically deformable material such as rubber.

[0024] The flat plate portion 21 has an outer diameter equal to the inner diameter of the recess 11b of the jig body 11, and is provided in the center thereof with a circular insertion hole 21a through which the bearing portion 3 of the movable scroll 1 is inserted.

[0025] Each of the protrusions 22 has a cylindrical outer shape that matches the inner shape of the recess 2a of the movable scroll 1, and is provided protruding from one surface in the thickness direction of the flat plate portion 21 at equal intervals from each other as the recesses 2a. In this case, each of the protrusions 22 is formed so that a part of it protrudes slightly outward from the outer circumferential edge of the flat plate portion 21.

[0026] In the masking jig 10 configured as above, first, the intermediate member 20 is attached to one end surface of the main body portion 2 of the movable scroll 1, as shown in Fig. 8. At that time, the bearing portion 3 of the movable scroll 1 is inserted into the insertion hole 21a of the intermediate member 20, and the protrusions 22 of the intermediate member 20 are fitted into the recesses 2a of the movable scroll 1 without any gaps.

[0027] Next, as shown in Figure 9, the other axial end face of the jig body 11 is opposed to one end face of the main body 2 of the movable scroll 1, and while holding the gripping portion 15 with the fingers, the jig body 11 is pressed against one end face of the main body 2 of the movable scroll 1, thereby attaching it to the movable scroll 1 as shown in Figure 10.

[0028] At that time, the first fitting portion 12 of the jig body 11 is inserted into the bearing portion 3, and the engaging portion 12a of the first fitting portion 12 engages with the engaging portion 3b between one axial end of the bush 3a and the bottom surface of the bearing portion 3, and the first fitting portion 12 fits into the inner peripheral surface of the bush 3a. In this case, the first fitting portion 12 elastically deforms radially inward, while the engaging portion 12a climbs over the bush 3a and engages with the engaging portion 3b, but since the recess 12b is provided on the central side of the first fitting portion 12, the first fitting portion 12 is more likely to elastically deform radially.

[0029] During the installation, the bearing portion 3 is inserted into the second fitting portion 13, and the pressure-contact portion 13a of the second fitting portion 13 elastically deforms and presses against the outer peripheral surface of the bearing portion 3, thereby fitting the second fitting portion 13 against the outer peripheral surface of the bearing portion 3.

[0030] Furthermore, the main body 2 of the movable scroll 1 is inserted into the third fitting portion 14, whereby the third fitting portion 14 fits into the outer circumferential surface of the main body 2 of the movable scroll 1. At that time, as shown in Fig. 10, the flat portion 21 of the intermediate member 20 attached to one end surface of the movable scroll 1 fits into the recess 11b of the jig body 11.

[0031] In this state, by attaching an elastic ring 16 to the third fitting portion 14, the third fitting portion 14 is pressed against the outer peripheral surface of the main body portion 2 of the movable scroll 1, thereby sealing the space between the jig body 11 and the movable scroll 1.

[0032] After the masking jig 10 is attached to the movable scroll 1 as described above, a hanging hook (not shown) is inserted into the through hole 15a of the gripping portion 15 of the masking jig 10 and the movable scroll 1 masked by the masking jig 10 is immersed in a liquid for surface treatment, thereby subjecting the movable scroll 1 masked by the masking jig 10 to a surface treatment (e.g., plating). At that time, even if vibration or impact is applied, the jig body 11 is securely held to the movable scroll 1 because the first fitting portion 12 and the second fitting portion 13 are fitted to sandwich the bearing portion 3 and the bush 3a of the movable scroll 1.

[0033] Furthermore, since each of the convex portions 22 of the intermediate member 20 is fitted into each of the concave portions 2a of the movable scroll 1, no space is created within each of the concave portions 2a where the convex portions 22 are fitted, and air does not expand within each of the concave portions 2a due to the heat of the high-temperature liquid used for surface treatment.

[0034] As described above, the masking jig 10 of this embodiment includes a first fitting portion 12 that fits into the inner peripheral surface of the bearing portion 3 and bush 3a of the movable scroll 1, and a second fitting portion 13 that fits into the outer peripheral surface of the bearing portion 3 of the movable scroll 1, so that the first fitting portion 12 and the second fitting portion 13 can fit to sandwich the bearing portion 3 and bush 3a of the movable scroll 1, and the jig body 11 can be securely held to the movable scroll 1. This effectively prevents the masking jig 10 from falling off the movable scroll 1 even when vibration or impact is applied.

[0035] Furthermore, an intermediate member 20 is provided between one end face of the movable scroll 1 and the jig body 11, and the convex portion 22 provided on the intermediate member 20 is fitted into the concave portion 2a of the movable scroll 1, thereby preventing the occurrence of space in each concave portion 2a, and thus suppressing the expansion of air in each concave portion 2a due to the heat of the high-temperature liquid used for surface treatment. As a result, even if the concave portion 2a is provided on one end face of the movable scroll 1, the jig body 11 does not shift in position or the sealing performance does not decrease due to the expansion of air in the concave portion 2a, and therefore masking failure and infiltration of liquid can be reliably prevented.

[0036] In this case, since the intermediate member 20 is made of a separate member from the jig body 11, even if the number, position, size, shape, etc. of the recesses 2a differ depending on the specifications and type of the movable scroll 1, it is only necessary to replace it with an intermediate member having a convex portion that corresponds to the specifications and type of the movable scroll 1, which has the advantage of being highly versatile.

[0037] Furthermore, when the jig body 11 is attached to the movable scroll 1, the flat plate portion 21 of the intermediate member 20 attached to one end surface of the movable scroll 1 is adapted to fit into the recess 11b of the jig body 11, so that the jig body 11 can be directly abutted against one end surface of the movable scroll 1. As a result, the position of the jig body 11 relative to the movable scroll 1 does not change regardless of the presence or absence of the intermediate member 20, so that even in the case of a movable scroll that does not have a recess on one end surface, for example, masking can be performed without using the intermediate member 20, thereby further enhancing versatility.

[0038] In addition, since the third fitting portion 14 of the jig body 11 is pressed against the outer peripheral surface of the main body portion 2 of the movable scroll 1 by a removable elastic ring 16, the space between the jig body 11 and the movable scroll 1 can be reliably sealed, and the intrusion of the surface treatment liquid can be reliably prevented.

[0039] Furthermore, since the jig body 11 is provided with a gripping portion 15 that can be gripped by fingers, the first and second fitting portions 12, 13 can be fitted into the bearing portion 3 and the bush 3a while gripping the gripping portion 15, and the masking jig 10 can be attached easily and reliably.

[0040] In the above embodiment, the convex portion 22 of the intermediate member 20 is formed so as to fit snugly into the concave portion 2a of the movable scroll 1, but if the effect of thermal expansion of air is small, a small space may be formed between the concave portion and the convex portion.

[0041] In addition, in the above embodiment, the movable scroll 1, which is a component of a scroll-type compressor, is shown as the object to be surface-treated. However, the present invention can be applied to objects other than the movable scroll as long as the object to be surface-treated has a cylindrical portion protruding from one end face and a recessed portion.

[0042] 11 to 14 show a second embodiment of the present invention, in which the same components as those in the first embodiment are denoted by the same reference numerals.

[0043] The masking jig 30 of this embodiment includes a jig body 31 formed so as to cover one end face side of the movable scroll 1, and the jig body 31 is adapted to be detachably attached to the movable scroll 1.

[0044] The jig body 31 is made of an elastically deformable material such as rubber, and is provided with a first fitting portion 32 that fits into the inner surface of the bearing portion 3 of the movable scroll 1, a second fitting portion 33 that fits into the outer surface of the bearing portion 3 of the movable scroll 1, a third fitting portion 34 that fits into the outer surface of the main body portion 2 of the movable scroll 1, a plurality of convex portions 35 that respectively fit into each recess 2a of the movable scroll 1, and a gripping portion 36 that can be held by fingers, and the third fitting portion 34 is configured to be pressed against the outer surface of the main body portion 2 of the movable scroll 1 by an elastic ring 37 which is a ring-shaped member.

[0045] The jig body 31 is formed in a circular plate shape, and a protrusion 31a is formed concentrically with the jig body 31 at the radial center of one end face of the jig body 31, protruding so as to be biased to one side in the axial direction (the opposite side to the mounting surface to the movable scroll 1).

[0046] The first fitting portion 32 is provided so as to protrude concentrically with the jig body 31 from the center of the other end surface of the jig body 31 toward the opposite side of the protruding portion 31a, and is formed in a cylindrical shape with an outer diameter equal to the inner diameter of the bush 3a of the bearing portion 3 of the movable scroll 1 and a length slightly shorter than the depth of the inner periphery of the bearing portion 3. An engagement portion 32a consisting of an annular protrusion protruding radially outward is formed on the edge on the tip side of the first fitting portion 32, and the engagement portion 32a is adapted to engage with the engagement portion 3b of the movable scroll 1. A recess 32b concentrically with the jig body 31 is provided on the center of the tip surface of the first fitting portion 32.

[0047] The second fitting portion 33 is provided so as to protrude concentrically from the other end face side of the jig body 31 toward the opposite side of the protruding portion 31a, and is formed in a cylindrical shape with a radial gap from the first fitting portion 32. In this case, the second fitting portion 33 is formed so that the inner diameter dimension is equal to the outer diameter dimension of the bearing portion 3 of the movable scroll 1, and the length dimension is equal to the height dimension of the outer circumferential side of the bearing portion 3. A pressure contact portion 33a consisting of an annular convex portion protruding radially inward is formed on the edge on the tip side of the second fitting portion 33, and the pressure contact portion 33a is configured to be in pressure contact with the outer circumferential surface of the bearing portion 3.

[0048] The third fitting portion 34 is provided so as to protrude concentrically with the jig body 31 from the peripheral edge side of the jig body 31 toward the opposite side of the protruding portion 31a, and is formed in a cylindrical shape whose inner diameter is equal to the outer diameter dimension of the body portion 2 of the movable scroll 1 and whose length dimension is slightly shorter than the height dimension of the outer circumferential side of the body portion 2. In addition, an annular groove portion 34a with which the elastic ring 36 engages is provided on the outer circumferential surface of the third fitting portion 34, and the groove portion 34a is formed in a substantially semicircular cross section.

[0049] Each protrusion 35 has a cylindrical outer shape that matches the inner shape of the recess 2a of the movable scroll 1, and is protruded from the other end face of the jig body 31 (the mounting surface for mounting to the movable scroll 1) at equal intervals from each other as the recesses 2a.

[0050] The grip portion 36 is provided so as to protrude from the protruding portion 31a in one axial direction, and is formed in a plate shape having two flat surfaces perpendicular to one end face of the protruding portion 31a. The grip portion 36 is also provided with a through hole 36a penetrating through both sides in the thickness direction, and the through hole 36a is adapted to receive a hook (not shown) for hanging.

[0051] The elastic ring 37 is made of a rubber O-ring, and when attached to the groove portion 34a of the third fitting portion 34, it presses the third fitting portion 34 against the outer peripheral surface of the main body portion 2 of the movable scroll 1.

[0052] The masking jig 30 configured as described above is attached to the movable scroll 1 as shown in FIG. 14 by facing the other axial end face of the jig body 31 toward one end face of the main body 2 of the movable scroll 1, and pressing the jig body 31 against one end face of the main body 2 of the movable scroll 1 while holding the gripping portion 36 with the fingers, as shown in FIG. 13.

[0053] At this time, each of the protrusions 35 of the jig body 11 is fitted into each of the recesses 2a of the movable scroll 1 without any gap. Also, the first fitting portion 32 of the jig body 11 is inserted into the bearing portion 3, and the engagement portion 32a of the first fitting portion 32 engages with the engagement portion 3b between one axial end of the bush 3a and the bottom surface of the bearing portion 3, so that the first fitting portion 32 fits into the inner peripheral surface of the bush 3a. In this case, the first fitting portion 32 elastically deforms radially inwardly, and the engagement portion 32a overcomes the bush 3a to engage with the engagement portion 3b, but since the recess 32b is provided on the central side of the first fitting portion 32, the first fitting portion 32 is easily elastically deformed radially.

[0054] During the mounting, the bearing portion 3 is inserted into the second fitting portion 33, and the pressure contact portion 33a of the second fitting portion 33 elastically deforms and presses against the outer circumferential surface of the bearing portion 3, so that the second fitting portion 33 fits into the outer circumferential surface of the bearing portion 3. Furthermore, the body portion 2 of the movable scroll 1 is inserted into the third fitting portion 34, so that the third fitting portion 34 fits into the outer circumferential surface of the body portion 2 of the movable scroll 1.

[0055] In this state, by attaching an elastic ring 37 to the third fitting portion 34, the third fitting portion 34 is pressed against the outer peripheral surface of the main body portion 2 of the movable scroll 1, thereby sealing the space between the jig body 31 and the movable scroll 1.

[0056] After the masking jig 30 is attached to the movable scroll 1 as described above, a hanging hook (not shown) is inserted into the through hole 35a of the gripping portion 35 of the masking jig 30 and the movable scroll 1 is immersed in a liquid for surface treatment, whereby the movable scroll 1 masked by the masking jig 30 is subjected to a surface treatment (e.g., plating). At this time, even if vibration or impact is applied, the jig body 31 is securely held to the movable scroll 1 because the first fitting portion 32 and the second fitting portion 33 are fitted to sandwich the bearing portion 3 and the bush 3a of the movable scroll 1.

[0057] Furthermore, since each of the protrusions 35 is fitted into each of the recesses 2a of the movable scroll 1, no space is created within each of the recesses 2a where the protrusions 35 are fitted, and air does not expand within each of the recesses 2a due to the heat of the high-temperature liquid used for surface treatment.

[0058] As described above, the masking jig 30 of this embodiment includes a first fitting portion 32 that fits into the inner peripheral surface of the bearing portion 3 and bush 3a of the movable scroll 1, and a second fitting portion 33 that fits into the outer peripheral surface of the bearing portion 3 of the movable scroll 1, so that the first fitting portion 32 and the second fitting portion 33 can fit to sandwich the bearing portion 3 and bush 3a of the movable scroll 1, similarly to the first embodiment, and the jig body 31 can be securely held to the movable scroll 1. This makes it possible to effectively prevent the masking jig 30 from falling off the movable scroll 1 even when vibration or impact is applied.

[0059] Furthermore, by fitting the protrusions 35 on the jig body 31 into the recesses 2a of the movable scroll 1, no space is created within each recess 2a, so that it is possible to suppress the expansion of air within each recess 2a due to the heat of the high-temperature liquid used for surface treatment. As a result, even if the recess 2a is provided on one end face of the movable scroll 1, the jig body 31 does not shift in position or the sealing performance does not decrease due to the expansion of air within the recess 2a, so that it is possible to reliably prevent masking defects and infiltration of liquid.

[0060] In this case, since each of the protrusions 35 is formed integrally with the jig body 31, the masking jig 30 can be quickly attached and detached. That is, when surface treatment is to be performed on a plurality of types of movable scrolls 1 having different numbers, positions, sizes, shapes, etc. of the recesses 2a, it is advantageous to have the intermediate member 20 formed separately from the jig body 11 as in the first embodiment, but when surface treatment is to be performed on a large number of movable scrolls 1 of the same type, the masking jig 30 of this embodiment, which does not require the attachment and detachment of the intermediate member 20, can be used to improve workability.

[0061] Furthermore, the third fitting portion 34 of the jig body 31 is pressed against the outer peripheral surface of the main body 2 of the movable scroll 1 by a removable elastic ring 37, so that, as in the first embodiment, the space between the jig body 31 and the movable scroll 1 can be reliably sealed, and the intrusion of the surface treatment liquid can be reliably prevented.

[0062] Furthermore, since the jig body 11 is provided with a gripping portion 36 that can be held by fingers, as in the first embodiment, the first and second fitting portions 22, 23 can be fitted into the bearing portion 3 and the bush 3a while gripping the gripping portion 36, and the masking jig 30 can be attached easily and reliably.

[0063] It should be noted that the above-described embodiments are merely examples of the present invention, and the present invention is not limited to those described in the embodiments. [Explanation of symbols]

[0064] 1...movable scroll, 2...main body, 2a...recess, 3...bearing portion, 3a...bush, 10...masking jig, 11...jig main body, 12...first fitting portion, 13...second fitting portion, 14...third fitting portion, 15...gripping portion, 16...elastic ring, 20...intermediate member, 22...protruding portion, 30...masking jig, 31...jig main body, 32...first fitting portion, 33...second fitting portion, 34...third fitting portion, 35...protruding portion, 36...gripping portion, 37...elastic ring.

Claims

1. A masking jig is attached to an object to be surface-treated, the object having at least one recess formed on one end surface and a cylindrical portion having an open end protruding from the center of the one end surface, and the masking jig is configured to cover the one end surface of the object to be surface-treated, the masking jig comprising: an intermediate member disposed between one end surface of the surface treatment object and the jig body, the intermediate member having a protrusion that fits into the recess; The jig body is provided with a first fitting portion whose outer circumferential surface fits into the inner circumferential surface of the cylindrical portion, and a second fitting portion whose inner circumferential surface fits into the outer circumferential surface of the cylindrical portion. A masking jig characterized by:

2. A masking jig is attached to an object to be surface-treated, the object having at least one recess formed on one end surface and a cylindrical portion having an open end protruding from the center of the one end surface, and the masking jig is configured to cover the one end surface of the object to be surface-treated, the masking jig comprising: The jig body is provided with a protrusion that fits into the recess, a first fitting portion whose outer circumferential surface fits into the inner circumferential surface of the cylindrical portion, and a second fitting portion whose inner circumferential surface fits into the outer circumferential surface of the cylindrical portion. A masking jig characterized by:

3. A ring-shaped member is provided on the peripheral surface of the jig body in a detachable manner to press the jig body against the object to be surface-treated.

2. The masking jig according to claim 1.

4. The jig body has a gripping portion that can be held by fingers, and is formed so that the first and second fitting portions are fitted into the cylindrical portion while the gripping portion is being held.

2. The masking jig according to claim 1.

5. A method for performing surface treatment by masking an object to be surface-treated using the masking jig according to any one of claims 1 to 4. A surface treatment method comprising:

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