Masking jig and surface treatment method using the same

Abstract

To provide a masking jig that can be reliably attached to a surface treatment target without requiring a space between itself and the surface treatment target to be under a negative pressure, and a surface treating method using the same.SOLUTION: A masking jig is provided with a first fitting unit 12 to be fitted to a shaft receiver 3 and the inner peripheral face of a bush 3a of a movable scroll 1, and a second fitting unit 13 to be fitted to the outer peripheral face of the shaft receiver 3 of the movable scroll 1, and hence the first fitting unit 12 and the second fitting unit 13 can be fitted to the shaft receiver 3 and the bush 3a of the movable scroll 1 in a manner of holding them in between, and the movable scroll 1 can reliably hold a jig body 11. Thereby, the space between the surface treatment target and the jig body need not to be under a negative pressure like before, and the masking jig 10 can be effectively prevented from falling off from the movable scroll 1 even when a vibration or a shock is given thereto.SELECTED DRAWING: Figure 5

Description

Technical Field

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

Background Art

[0002] Generally, when performing surface treatment on parts of various industrial products, the surface treatment is performed while masking the parts that are not to be surface-treated. For example, a movable scroll, which is a part of a scroll-type compressor, has a cylindrical bearing portion protruding from the center of one end surface thereof, and surface treatment is performed on a portion other than the bearing portion or a portion outside a predetermined range including the bearing portion. At that time, a dedicated masking jig is attached to the part, and a portion that is not to be surface-treated is masked by the masking jig (see, for example, Patent Document 1).

[0003] This masking jig is composed of an elastically deformable member having a cylindrical seal portion that covers the outer peripheral surface of the bearing portion and a bottom portion that covers one end of the bearing portion. After being attached to the bearing portion, the internal space of the bearing portion sealed by the bottom portion is made negative pressure so that the jig body does not easily come off from the part. In this case, the internal space of the bearing portion is made negative pressure by pressing the bottom portion of the masking jig from the outside to extrude the air in the internal space of the bearing portion.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, with the conventional masking jig described above, it was necessary to press the bottom surface of the masking jig to expel the internal air, which increased the number of work steps. Furthermore, if the worker neglected to perform this step, there was a problem in that the masking jig attached to the part would fall off. In addition, if negative pressure was created in the space between the object to be surface treated and the jig, there was a risk that the liquid used for surface treatment would be drawn into the bearing part.

[0006] The present invention has been made in view of the above-mentioned problems, and its object is to provide a masking jig that can be reliably attached to a surface-treated object without the need to create a negative pressure in the space between the jig and the object to be surface-treated, and a surface treatment method using the same. [Means for solving the problem]

[0007] To achieve the above objective, the present invention provides a masking jig that is attached to a surface treatment object having a cylindrical portion protruding from one end and is formed to cover at least the surface of the cylindrical portion of the surface treatment object, wherein the jig body is provided with a first fitting portion whose outer surface fits into the inner surface of the cylindrical portion and a second fitting portion whose inner surface fits into the outer surface of the cylindrical portion.

[0008] As a result, when the jig body is attached to the object to be surface treated, the outer surface of the first fitting part fits into the inner surface of the cylindrical part, and the inner surface of the second fitting part fits into the outer surface of the cylindrical part, so that the first fitting part and the second fitting part fit together so as to sandwich the cylindrical part. [Effects of the Invention]

[0009] According to the present invention, the cylindrical portion can be fitted by sandwiching it between the first and second fitting portions, so that the jig body can be securely held to the object to be surface treated. As a result, it is not necessary to create negative pressure in the space between the jig and the object to be surface treated, as in the conventional method, and it is possible to effectively prevent the jig from falling off the object to be surface treated even when vibration or shock is applied. [Brief explanation of the drawing]

[0010] [Figure 1] Plan view of the jig body of the masking jig showing an embodiment of the present invention [Figure 2] Bottom view of the jig body [Figure 3] Front view of the jig body [Figure 4] Perspective view of the masking jig and the movable scroll [Figure 5] Side cross-sectional view showing the mounting process of the masking jig [Figure 6] Side cross-sectional view showing the mounted state of the masking jig [Figure 7] Plan view of the jig body of the masking jig showing another embodiment of the present invention [Figure 8] Bottom view of the jig body [Figure 9] Front view of the jig body [Figure 10] Plan view of the press-fitting member [Figure 11] Bottom view of the press-fitting member [Figure 12] Front view of the press-fitting member [Figure 13] Side view of the press-fitting member [Figure 14] Perspective view of the masking jig and the movable scroll [Figure 15] Side cross-sectional view showing the mounting process of the masking jig [Figure 16] Side cross-sectional view showing the mounting process of the masking jig [Figure 17] Side cross-sectional view showing the mounted state of the masking jig

Embodiments for Carrying Out the Invention

[0011] Figs. 1 to 6 show an embodiment of the present invention, and show a masking jig used in a surface treatment process of a movable scroll which is a part of a scroll-type compressor, for example.

[0012] The movable scroll 1 as the object to be surface-treated 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 is attached to the inner peripheral surface of the bearing portion 3. The bearing portion 3 and the bush 3a form a cylindrical portion. The inside of the bearing portion 3 is formed deeper than one end surface of the main body portion 2, and an engaging portion 3b in the form 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. A scroll portion 4 eccentric in the radial direction protrudes from the other end surface of the main body portion 2, and although not shown, the inside of the scroll portion 4 is formed in a spiral shape.

[0013] The masking jig 10 of the present embodiment includes a jig main body 11 formed to cover one end surface side of the movable scroll 1, and the jig main body 11 is detachably attached to the movable scroll 1.

[0014] The jig main body 11 is made of an elastically deformable member such as rubber, and includes a first fitting portion 12 that fits into the inner peripheral surface of the bearing portion 3 of the movable scroll 1, a second fitting portion 13 that fits into the outer peripheral surface of the bearing portion 3 of the movable scroll 1, a third fitting portion 14 that fits into the outer peripheral surface of the main body portion 2 of the movable scroll 1, and a gripping portion 15 that can be gripped by a finger. The third fitting portion 14 is crimped to the outer peripheral surface of the main body portion 2 of the movable scroll 1 by an elastic ring 16 as a ring-shaped member.

[0015] The jig main body 11 is formed in a disk shape, and a protruding portion 11a that protrudes so as to be unevenly distributed in one axial direction (the opposite side of the mounting surface to the movable scroll 1) is formed concentrically with the jig main body 11 on the radially central side of one end surface thereof. Further, a recess 11b concentric with the jig main body 11 is provided on the other end surface (the mounting surface to the movable scroll 1) of the jig main body 11, and the outer diameter of the recess 11b is formed larger than the outer diameter of the protruding portion 11a.

[0016] The first fitting portion 12 is provided so as to protrude concentrically from the center of the other end face of the jig body 11 toward the opposite side of the projection 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 inner depth of the bearing portion 3. An engaging portion 12a consisting of an annular projection that protrudes radially outward is formed at the tip edge of the first fitting portion 12, and the engaging portion 12a is designed to engage with the engaging portion 3b of the movable scroll 1. In addition, a recess 12b concentrically with the jig body 11 is provided on the center side of the tip face of the first fitting portion 12.

[0017] The second fitting portion 13 is provided so as to protrude concentrically from the other end face of the jig body 11 toward the opposite side of the projection 11a, and is formed in a cylindrical shape with a radial gap between it and the first fitting portion 12. In this case, the second fitting portion 13 is formed such that its inner diameter is equal to the outer diameter of the bearing portion 3 of the movable scroll 1, and its length is equal to the height of the outer circumference of the bearing portion 3. A pressure contact portion 13a consisting of an annular projection that protrudes radially inward is formed at the tip edge of the second fitting portion 13, and the pressure contact portion 13a is designed to press against the outer circumference of the bearing portion 3.

[0018] The third fitting portion 14 is provided so as to protrude concentrically from the peripheral edge of the jig body 11 toward the opposite side of the protruding portion 11a, and is formed in a cylindrical shape with an inner diameter equal to the outer diameter of the main body portion 2 of the movable scroll 1 and a length slightly shorter than the height of the outer circumference of the main body portion 2. Furthermore, an annular groove portion 14a into 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.

[0019] The gripping portion 15 is provided so as to protrude from the projection portion 11a in one axial direction and is formed in a plate shape having two planes perpendicular to one end face of the projection portion 11a. The gripping portion 15 is also provided with through holes 15a that penetrate both sides in the thickness direction, and the through holes 15a are designed for inserting a hanging hook (not shown).

[0020] The elastic ring 16 is made of a rubber O-ring and is fitted into the groove 14a of the third fitting part 14, thereby pressing the third fitting part 14 against the outer circumferential surface of the main body 2 of the movable scroll 1.

[0021] As shown in Figure 5, the masking jig 10 is attached to the movable scroll 1 by pressing the jig body 11 against one end face of the main body 2 of the movable scroll 1 while gripping the gripping part 15 with the fingers, as shown in Figure 6.

[0022] 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, so that the first fitting portion 12 fits onto the inner circumferential surface of the bush 3a. In this case, the engaging portion 12a overcomes the bush 3a and engages with the engaging portion 3b as the first fitting portion 12 elastically deforms radially inward. However, since a recess 12b is provided on the central side of the first fitting portion 12, the first fitting portion 12 is more easily elastically deformed radially.

[0023] Furthermore, during 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 circumferential surface of the bearing portion 3, thereby fitting the second fitting portion 13 to the outer circumferential surface of the bearing portion 3.

[0024] Furthermore, when the main body portion 2 of the movable scroll 1 is inserted into the third fitting portion 14, the third fitting portion 14 fits onto the outer circumferential surface of the main body portion 2 of the movable scroll 1. At this time, a space is formed between the jig body 11 and one end face of the movable scroll 1 by the recess 11b. In this state, by attaching the elastic ring 16 to the third fitting portion 14, the third fitting portion 14 is pressed against the outer circumferential surface of the main body portion 2 of the movable scroll 1, and the space between the jig body 11 and the movable scroll 1 is sealed.

[0025] After attaching the masking jig 10 to the movable scroll 1 as described above, a suspension hook (not shown) is inserted through the through hole 15a of the gripping portion 15 of the masking jig 10, and the jig is immersed in a surface treatment liquid, thereby applying a surface treatment (e.g., plating) to the movable scroll 1 masked by the masking jig 10. At that time, even if vibration or shock is applied, the first fitting portion 12 and the second fitting portion 13 are fitted so as to sandwich the bearing portion 3 and bush 3a of the movable scroll 1, so the jig body 11 is securely held to the movable scroll 1 without creating negative pressure in the internal space of the bearing portion as in the conventional method.

[0026] As described above, the masking jig 10 of this embodiment includes a first fitting portion 12 that fits onto the inner circumferential surface of the bearing portion 3 and bush 3a of the movable scroll 1, and a second fitting portion 13 that fits onto the outer circumferential surface of the bearing portion 3 of the movable scroll 1. Therefore, the first fitting portion 12 and the second fitting portion 13 can be used to sandwich and fit the bearing portion 3 and bush 3a of the movable scroll 1, and the jig body 11 can be securely held on the movable scroll 1. This eliminates the need to create negative pressure in the space between the jig and the object to be surface treated, as in the conventional method, and effectively prevents the masking jig 10 from falling off the movable scroll 1 even when vibration or shock is applied.

[0027] Furthermore, since the third fitting portion 14 of the jig body 11 is pressed against the outer circumferential surface of the main body 2 of the movable scroll 1 by an elastic ring 16 that can be attached to the third fitting portion 14 of the jig body 11, the space between the jig body 11 and the movable scroll 1 can be reliably sealed, and the intrusion of surface treatment liquid can be reliably prevented.

[0028] Furthermore, since the jig body 11 is provided with a gripping portion 15 that can be grasped with the fingers, the first and second fitting portions 12 and 13 can be fitted into the bearing portion 3 and bush 3a while gripping the gripping portion 15, making it easy and reliable to attach the masking jig 10.

[0029] Figures 7 to 17 show other embodiments of the present invention, and components equivalent to those in the above embodiments are denoted by the same reference numerals.

[0030] The masking jig 20 of this embodiment comprises a jig body 21 formed to cover the bearing portion 3 of the movable scroll 1, and a press-fitting member 30 that is press-fitted into the jig body 21, and the jig body 21 is detachably attached to the movable scroll 1.

[0031] The jig body 21 is made of an elastically deformable material such as rubber and includes a first fitting portion 22 that fits onto the inner circumferential surface of the bearing portion 3 of the movable scroll 1, a second fitting portion 23 that fits onto the outer circumferential surface of the bearing portion 3 of the movable scroll 1, and a recess 24 into which the press-fitting member 30 is press-fitted. The second fitting portion 23 is pressed against the outer circumferential surface of the main body portion 2 of the movable scroll 1 by an elastic ring 25 which is a ring-shaped member.

[0032] The jig body 21 is formed in a disc shape, and one end face (the face opposite to the mounting surface to the movable scroll 1) is formed to be a flat surface.

[0033] The first fitting portion 22 is provided so as to protrude concentrically from the center of the other end face (the mounting surface to the movable scroll 1) of the jig body 21, 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 equal to the inner depth of the bearing portion 3. An engaging portion 22a consisting of an annular projection that protrudes radially outward is formed at the tip edge of the first fitting portion 22, and the engaging portion 22a is designed to engage with the engaging portion 3b of the movable scroll 1.

[0034] The second fitting portion 23 is provided so as to protrude concentrically from the peripheral edge of the jig body 21 in the same direction as the first fitting portion 22, and is formed in a cylindrical shape with a radial gap between it and the first fitting portion 22. In this case, the second fitting portion 23 is formed such that its inner diameter is equal to the outer diameter of the bearing portion 3 of the movable scroll 1, and its length is slightly shorter than the height of the outer circumference of the bearing portion 3. A pressure contact portion 23a consisting of an annular protrusion that protrudes radially inward is formed at the tip edge of the second fitting portion 23, and the pressure contact portion 23a is designed to press against the outer circumferential surface of the bearing portion 3. Furthermore, an annular groove portion 23b into which the elastic ring 25 engages is provided on the outer circumferential surface of the second fitting portion 23, and the groove portion 23b is formed in a substantially semicircular cross-section.

[0035] The recess 24 is formed concentrically with the jig body 21 and is provided on the first fitting portion 22 such that one end opens to one end face of the jig body 21. As a result, the first fitting portion 22 has a bottomed cylindrical shape with the recess 24 on its inside.

[0036] The elastic ring 25 is made of a rubber O-ring and is fitted into the groove 23b of the second fitting portion 23, thereby pressing the second fitting portion 23 against the outer circumferential surface of the main body portion 2 of the movable scroll 1.

[0037] The press-fit member 30 consists of a disc-shaped main body 31, a gripping portion 32 that can be grasped with the fingers, and a protrusion 33 that is press-fitted into the recess 24 of the jig body 21. The main body 31 is formed so that its outer diameter is smaller than the outer diameter of the jig body 21 and larger than the inner diameter of the recess 24.

[0038] The gripping portion 32 is provided so as to protrude from the main body portion 31 in one axial direction and is formed in a plate shape having two planes perpendicular to one end face of the main body portion 31. The gripping portion 32 is provided with through holes 32a that penetrate both sides in the thickness direction, and the through holes 32a are designed for inserting a suspension hook (not shown).

[0039] The protrusion 33 is provided so as to protrude from the main body 31 in the other axial direction, and is formed such that its outer diameter is slightly larger than the inner diameter of the recess 24, and its length is equal to the depth of the inner circumference of the recess 24.

[0040] As shown in Figure 15, the masking jig 20 is configured such that the other axial end face of the jig body 21 faces the bearing portion 3 of the movable scroll 1, and the jig body 21 is mounted on the movable scroll 1 as shown in Figure 16.

[0041] At that time, the first fitting portion 22 of the jig body 21 is inserted into the bearing portion 3, and the engaging portion 22a of the first fitting portion 22 engages with the engaging 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 22 fits onto the inner circumferential surface of the bush 3a. In this case, the engaging portion 22a overcomes the bush 3a and engages with the engaging portion 3b as the first fitting portion 22 elastically deforms radially inward. However, since the first fitting portion 22 is provided with a recess 24, the first fitting portion 22 is more easily elastically deformed radially.

[0042] Furthermore, during the installation process, the bearing portion 3 is inserted into the second fitting portion 23, and the pressure contact portion 23a of the second fitting portion 23 elastically deforms and presses against the outer circumferential surface of the bearing portion 3, thereby fitting the second fitting portion 23 to the outer circumferential surface of the bearing portion 3. In this state, by attaching the elastic ring 25 to the second fitting portion 23, the second fitting portion 23 is pressed against the outer circumferential surface of the bearing portion 3 of the movable scroll 1, thereby sealing the space between the jig body 21 and the movable scroll 1.

[0043] After attaching the jig body 21 to the movable scroll 1, the press-fit member 30 is attached to the jig body 21 as shown in Figure 16. At this time, the press-fit member 30 is held in place on the jig body 21 as shown in Figure 17 by pressing the convex portion 33 into the recess 24 of the jig body 21 while gripping the grip portion 15 with the fingers. Furthermore, the press-fitting of the press-fit member 30 causes the inner circumferential surface of the recess 24 to be pressed radially by the convex portion 33 of the press-fit member 30, and the second fitting portion 23 is pressed against the inner circumferential surface of the bearing portion 3 and the bush 3a.

[0044] After attaching the masking jig 20 to the movable scroll 1 as described above, a suspension hook (not shown) is inserted through the through hole 32a of the press-fitting member 30 of the masking jig 20, and the jig is immersed in a surface treatment liquid, thereby applying a surface treatment (e.g., plating) to the movable scroll 1 masked by the masking jig 20. At that time, even if vibration or shock is applied, the first fitting portion 22 and the second fitting portion 23 fit together so as to sandwich the bearing portion 3 and bush 3a of the movable scroll 1, and the outer circumferential surface of the second fitting portion 23 is pressed against the inner circumferential surface of the bearing portion 3 and bush 3a by the press-fitting of the press-fitting member 30, so that the jig body 21 is securely held to the movable scroll 1 without creating negative pressure in the internal space of the bearing portion as in the conventional method.

[0045] Thus, the masking jig of this embodiment 2 0 comprises a first fitting portion 22 that fits into the inner circumferential surface of the bearing portion 3 and bush 3a of the movable scroll 1, and a second fitting portion 23 that fits into the outer circumferential surface of the bearing portion 3 of the movable scroll 1, and also comprises a press-fitting member 30 that is press-fitted into a recess 24 provided in the second fitting portion 23, so the first fitting portion 2 2 and second fitting part 2 The bearing portion 3 and bush 3a of the movable scroll 1 can be fitted together by clamping them, and the press-fitting member 30 presses the outer surface of the second fitting portion 23 against the inner surface of the bearing portion 3 and bush 3a, thereby securely holding the jig body 21 to the movable scroll 1. As a result, it is not necessary to create negative pressure in the space between the jig and the object to be surface treated, as in the conventional method, and the masking jig 20 can be effectively prevented from falling off the movable scroll 1 even when vibration or shock is applied.

[0046] Furthermore, since the second fitting portion 23 of the jig body 21 is pressed against the outer circumferential surface of the main body 2 of the movable scroll 1 by an elastic ring 25 that can be attached to and removed from the second fitting portion 23 of the jig body 21, the space between the jig body 21 and the movable scroll 1 can be reliably sealed, and the intrusion of surface treatment liquid can be reliably prevented.

[0047] Furthermore, since the press-fitting member 30 is provided with a gripping portion 32 that can be grasped with the fingers, the press-fitting member 30 can be pressed into the jig body 21 while gripping the gripping portion 32, making it easy and reliable to attach the press-fitting member 30.

[0048] In the embodiments described above, the engagement portions 12a and 22a, which are annular protrusions provided on the masking jigs 10 and 20, are shown to be engaged with the engagement portion 3b, which is an annular recess formed in the bearing portion 3 of the movable scroll 1. However, the device may not have such a recess and protrusion.

[0049] Furthermore, although the embodiments described above show the use of elastic rings 16 and 25 as ring-shaped members, it is also possible to use metal ring-shaped members.

[0050] Furthermore, although the above embodiments show a movable scroll 1, which is a part of a scroll-type compressor, as the object to be surface treated, the present invention can be applied to objects other than movable scrolls as long as they have a cylindrical portion protruding from one end that is open. [Explanation of Symbols]

[0051] 1...Movable scroll, 3...Bearing part, 3a...Bush, 10...Masking jig, 11...Jig body, 12...First fitting part, 13...Second fitting part, 14...Third fitting part, 15...Gripping part, 16...Elastic ring, 20...Masking jig, 21...Jig body, 22...First fitting part, 23...Second fitting part, 24...Recess, 25...Elastic ring, 30...Press-fit member, 32...Gripping part.

Claims

1. A masking jig is attached to an object to be surface treated, which has a cylindrical portion protruding from one end that is open, and the jig body is formed to cover at least the surface of the cylindrical portion of the object to be surface treated, and the object to be surface treated is masked by the jig body, The jig body is provided with a first fitting portion whose outer surface fits into the inner surface of the cylindrical portion, and a second fitting portion whose inner surface fits into the outer surface of the cylindrical portion. The tip edge of the first fitting portion is provided with an elastically deformable annular projection that protrudes radially outward. A masking jig characterized by the following features.

2. A masking jig that is attached to an object to be surface treated, which has a cylindrical portion protruding from one end that is open, and which masks the object to be surface treated by a jig body formed to cover at least the surface of the cylindrical portion of the object to be surface treated, The jig body is provided with a first fitting portion whose outer surface fits into the inner surface of the cylindrical portion, and a second fitting portion whose inner surface fits into the outer surface of the cylindrical portion. The tip edge of the second fitting portion is provided with an elastically deformable annular projection that protrudes radially inward. A masking jig characterized by the following features.

3. A masking jig that is attached to an object to be surface treated, which has a cylindrical portion protruding from one end that is open, and which masks the object to be surface treated by a jig body formed to cover at least the surface of the cylindrical portion of the object to be surface treated, The jig body is provided with a first fitting portion whose outer surface fits into the inner surface of the cylindrical portion, and a second fitting portion whose inner surface fits into the outer surface of the cylindrical portion. The tip edge of the first fitting portion is provided with an elastically deformable annular projection that protrudes radially outward, and the tip edge of the second fitting portion is provided with an elastically deformable annular projection that protrudes radially inward. A masking jig characterized by the following features.

4. The jig body is detachably provided with a ring-shaped member that presses the jig body against the object to be surface treated. A masking jig according to any one of claims 1 to 3, characterized by the features described herein.

5. The jig body has a gripping portion that can be grasped with the fingers, and is formed so that the first and second fitting portions can be fitted into the cylindrical portion while gripping the gripping portion. A masking jig according to any one of claims 1 to 4, characterized by the present invention.

6. The first fitting portion is equipped with a press-fitting member that can be press-fitted into the recess provided therein. The first fitting portion is formed to be pressed against the inner circumferential surface of the cylindrical portion by the press-fitting member which is press-fitted into the recess. A masking jig according to any one of claims 1 to 3, characterized by the features described herein.

7. The press-fitting member has a gripping portion that can be grasped with the fingers, and is formed to be pressed into the recess while gripping the gripping portion. The masking jig according to feature 6.

8. The surface treatment is performed by masking the object to be surface treated with a masking jig according to any one of claims 1 to 7. A surface treatment method characterized by the following:

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