Scroll compressor

Abstract

In a scroll compressor (100), a fixed scroll (31) has a protrusion part (31GG) having a first outer peripheral surface (31G2) and a second outer peripheral surface (31G1) on a lower side of the protrusion part (31GG) in an axial direction (Y). An upper shell (12) has a first step part (12NN) on a lower side in the axial direction (Y) on an inner peripheral surface thereof on a middle shell (11) side. An upper end surface (31F3) of the protrusion part (31GG) contacts a first step surface (12F4) of the first step part (12NN), and a lower end surface (31F2) of the protrusion part (31GG) contacts and is fixed to an upper end surface (11F1) of the middle shell (11). The second outer peripheral surface (31G1) of the fixed scroll (31) contacts a first inner peripheral surface (11N1) of the middle shell (11). A first inner peripheral surface (12N2) of the first step part (12NN) of the upper shell (12) contacts a first outer peripheral surface (11G1) of the middle shell (11).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a scroll compressor. BACKGROUND ART

[0002] A scroll compressor has an orbiting scroll supported by a frame fixed inside a shell, and a fixed scroll fixed to the frame by a bolt or the like so as to be opposed to the orbiting scroll. A crankshaft is attached to the orbiting scroll. When the crankshaft is rotated, the orbiting scroll swings relative to the fixed scroll, whereby a refrigerant is compressed in a compression chamber formed by the orbiting scroll and the fixed scroll. Since the compression chamber for compressing the refrigerant is formed between the fixed scroll and the orbiting scroll, position accuracy of the fixed scroll relative to the orbiting scroll is important, and a method for fixing the fixed scroll to the frame easily and with high accuracy is required.

[0003] In a conventional scroll compressor, a peripheral wall of a frame extends toward a fixed scroll, and a cylindrical portion provided on the outer side of a fixed wrap of the fixed scroll is fitted to an inner circumferential surface at an end of the peripheral wall. A flange portion provided at a frame outermost circumferential portion and a flange portion provided at an outermost circumferential portion of a fixed scroll peripheral wall are clamped between an end surface of a cylindrical center shell and a lid cap covering an opening end surface of the center shell which are welded to each other, whereby the fixed scroll and the frame are fixed. Thus, shaft alignment between the frame and the fixed scroll is facilitated, and the flange portion provided to the frame outermost circumferential portion and the flange portion provided to the fixed scroll outermost circumferential portion are overlapped with each other, whereby position accuracy is ensured (see, for example, Patent Document 1). CITATION LIST PATENT DOCUMENT

[0004] Patent Document 1: Japanese Laid-Open Patent Publication No. 2018-189027 SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0005] In the conventional scroll compressor, the peripheral wall of the frame and the cylindrical portion provided on the outer side of the fixed wrap of the fixed scroll so as to correspond to the inner diameter side of the peripheral wall of the frame, are needed, so that the sizes of the frame and the fixed scroll increase. Thus, the cost increases, and in a case of using the same cylindrical housing, the compression chamber is reduced due to provision of the above mechanism, resulting in reduction in the compression volume.

[0006] The present disclosure has been made to solve the above problem, and an object of the present disclosure is to provide a scroll compressor having an increased compression volume for a refrigerant without increasing the size of the apparatus. MEANS TO SOLVE THE PROBLEM

[0007] A scroll compressor according to the present disclosure includes: an orbiting scroll; a frame retaining the orbiting scroll slidably; a fixed scroll forming a compression chamber together with the orbiting scroll; a middle shell storing the frame, the orbiting scroll, and the fixed scroll; and an upper shell sealing an upper side of the fixed scroll on the middle shell. The fixed scroll has a protrusion protruding outward in a radial direction between outer circumferential surfaces in an axial direction and having a first outer circumferential surface, and a second outer circumferential surface on a lower side in the axial direction relative to the protrusion. The upper shell has a first step portion where an inner diameter is increased on a lower side in the axial direction, at an inner circumferential surface on the middle shell side. The fixed scroll is fixed such that an upper end surface in the axial direction of the protrusion contacts with a first step surface of the first step portion of the upper shell and a lower end surface in the axial direction of the protrusion contacts with an upper end surface in the axial direction of the middle shell. The second outer circumferential surface of the fixed scroll is formed in contact with a first inner circumferential surface on an upper side in the axial direction of the middle shell. A first inner circumferential surface on a lower side in the axial direction of the first step portion of the upper shell is formed in contact with a first outer circumferential surface on an upper side in the axial direction of the middle shell. EFFECT OF THE INVENTION

[0008] With the scroll compressor according to the present disclosure, the compression volume for a refrigerant can be increased without increasing the size of the apparatus. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] [FIG. 1] FIG. 1 is a sectional view showing a configuration of a scroll compressor according to embodiment 1. [FIG. 2] FIG. 2 is an enlarged view of a part enclosed by a dotted line SI in the scroll compressor shown in FIG. 1. [FIG. 3] FIG. 3 is an enlarged view of a part enclosed by a dotted line S2 in the scroll compressor shown in FIG. 2. [FIG. 4] FIG. 4 is an enlarged view of another example of the part enclosed by the dotted line S2 in the scroll compressor shown in FIG. 2. [FIG. 5] FIG. 5A is a plan view showing another configuration of a fixed scroll of the scroll compressor according to embodiment 1, and FIG. 5B is a sectional view thereof along line I-I shown in FIG. 5A. [FIG. 6] FIG. 6 is a partial sectional view showing a configuration of a scroll compressor according to embodiment 2. [FIG. 7] FIG. 7 is a partial sectional view showing a configuration of a scroll compressor according to embodiment 3. [FIG. 8] FIG. 8 is a partial sectional view showing a configuration of a scroll compressor according to embodiment 4. [FIG. 9] FIG. 9 is a partial sectional view showing a configuration of the scroll compressor shown in FIG. 8. [FIG. 10] FIG. 10 is a partial sectional view showing a configuration of a scroll compressor in a comparative example. [FIG. 11] FIG. 11 is a partial sectional view showing another configuration of the scroll compressor according to embodiment 1. [FIG. 12] FIG. 12 is a partial sectional view showing a configuration of a scroll compressor according to embodiment 5. [FIG. 13] FIG. 13 shows the relationship between a formation position of a welding portion and deformation amounts of a fixed scroll and a frame, in the scroll compressor according to embodiment 5. [FIG. 14] FIG. 14 is a partial sectional view showing a configuration of a scroll compressor according to embodiment 6. [FIG. 15] FIG. 15 is an enlarged view of a part enclosed by a dotted line S3 in the scroll compressor shown in FIG. 14. DESCRIPTION OF EMBODIMENTS

[0010] Embodiment 1 FIG. 1 is a sectional view showing a configuration of a scroll compressor according to embodiment 1. FIG. 2 is an enlarged view of a part enclosed by a dotted line SI in the scroll compressor shown in FIG. 1. FIG. 3 is an enlarged view of a part enclosed by a dotted line S2 in the scroll compressor shown in FIG. 2. FIG. 4 is an enlarged view of another example of the part enclosed by the dotted line S2 in the scroll compressor shown in FIG. 2. FIG. 5A is a plan view showing another configuration of a fixed scroll of the scroll compressor according to embodiment 1, and FIG. 5B is a sectional view thereof along line I-I shown in FIG. 5A. FIG. 11 is a partial sectional view showing another configuration of the scroll compressor according to embodiment 1.

[0011] Hereinafter, a scroll compressor 100 according to the present embodiment 1 will be described with reference to the drawings. First, as shown in FIG. 1, in the scroll compressor 100, an up-down direction on the drawing is defined as an axial direction Y (corresponding to an axial direction Y of a crankshaft 6 described later), and a direction that is perpendicular to the axial direction Y and is a left-right direction on the drawing is defined as a radial direction X. In the drawing, "U SIDE" indicates an upper side in the axial direction Y, and "L SIDE" indicates a lower side in the axial direction Y. In the other drawings, "U SIDE" and "L SIDE" correspond to "U SIDE" and "L SIDE" in FIG. 1. Such a relationship also applies in the other embodiments and therefore the description thereof is omitted as appropriate.

[0012] The scroll compressor 100 according to the present embodiment 1 will be described with reference to the drawings. As shown in FIG. 1, the scroll compressor 100 includes, as main components: a shell 1 including a middle shell 11, an upper shell 12 provided on the U side of the middle shell 11 and having a discharge pipe 15, and a lower shell 13 provided on the L side of the middle shell 11; the crankshaft 6 supported by a bearing 20 of the middle shell 11; and a driving portion 4 for rotationally driving the crankshaft 6.

[0013] Further, the scroll compressor 100 includes: an orbiting scroll 32 provided to an eccentric shaft portion 62 of the crankshaft 6; a compression chamber 34 formed for compressing a refrigerant; a frame 2 which supports the orbiting scroll 32, has the bearing 20 supporting the crankshaft 6, and is fixed to the middle shell 11; and a sub frame 50 fixed to the middle shell 11.

[0014] First, operation of the scroll compressor 100 configured as described above will be described. Through operation of the driving portion 4, the crankshaft 6 rotates and the refrigerant passes through the frame 2, to flow into the compression chamber 34. Here, the orbiting scroll 32 provided to the eccentric shaft portion 62 of the crankshaft 6 swings, so that the refrigerant is compressed in the compression chamber 34. The compressed refrigerant flows into the discharge pipe 15 via a fixed scroll 31.

[0015] Next, the details of components will be described with reference to FIG. 2 which is an enlarged view of the part enclosed by the dotted line SI in the scroll compressor 100 shown in FIG. 1 and FIG. 3 which is an enlarged view of the part enclosed by the dotted line S2 in the scroll compressor 100 shown in FIG. 3. FIG. 3 shows only an upper part on the left side in the radial direction X on the drawing in FIG. 2, but a part symmetric with the part shown in FIG. 3 is formed on the right side in the radial direction X on the drawing, as shown in FIG. 2 or FIG. 1.

[0016] As shown in FIG. 3, the fixed scroll 31 has a protrusion 31GG protruding outward in the radial direction X between outer circumferential surfaces in the axial direction Y. The protrusion 31GG has a first outer circumferential surface 31G2. The fixed scroll 31 has a second outer circumferential surface 31G1 on the lower side in the axial direction Y relative to the protrusion 31GG. The fixed scroll 31 has an upper end surface 31F3 on the upper side in the axial direction Y of the protrusion 31GG, and a lower end surface 31F2 on the lower side in the axial direction Y of the protrusion 31GG.

[0017] The first outer circumferential surface 31G2 of the protrusion 31GG of the fixed scroll 31 is a part having a largest outer diameter, of the fixed scroll 31. Therefore, as shown in FIG. 2, an outer diameter W1 of the first outer circumferential surface 31G2 of the protrusion 31GG of the fixed scroll 31 is larger than an outer diameter W2 of the second outer circumferential surface 31G1 of the fixed scroll 31.

[0018] The upper shell 12 has a first step portion 12NN where the inner diameter is increased on the lower side in the axial direction Y, at an inner circumferential surface on the middle shell 11 side. The upper shell 12 has a first step surface 12F4 of the first step portion 12NN, a first inner circumferential surface 12N2 on the lower side in the axial direction Y of the first step portion 12NN, a second inner circumferential surface 12N3 on the upper side in the axial direction Y of the first step portion 12NN, and a lower end surface 12F5 at a lower end in the axial direction Y. Therefore, an inner diameter Hl of the first inner circumferential surface 12N2 of the upper shell 12 is larger than an inner diameter H2 of the second inner circumferential surface 12N3 of the upper shell 12.

[0019] The outer diameter W1 of the first outer circumferential surface 31G2 of the fixed scroll 31 is smaller than the inner diameter Hl of the first inner circumferential surface 12N2 of the upper shell 12. With this configuration, a gap is formed in the radial direction X between the first inner circumferential surface 12N2 of the upper shell 12 and the first outer circumferential surface 31G2 of the protrusion 31GG of the fixed scroll 31. Since the gap is formed, the upper shell 12 and the first outer circumferential surface 31G2 of the protrusion 31GG of the fixed scroll 31 do not contact with each other, and therefore work for fitting the upper shell 12 to the middle shell 11 can be facilitated.

[0020] In the drawings, the part of the fixed scroll 31 that contacts with the first step surface 12F4 of the upper shell 12 is the upper end surface 31F3 of the protrusion 31GG of the fixed scroll 31. However, the contact part is not limited to that shown in the drawings and may be any surface as long as the surface is an upper end surface (an end surface perpendicular to the axial direction Y) on the upper side in the axial direction Y relative to the protrusion 31GG of the fixed scroll 31.

[0021] The middle shell 11 has a first outer circumferential surface 11G1 on the upper side in the axial direction Y, an upper end surface 11F1 in the axial direction Y, and a second step portion 11NN where the inner diameter is reduced, on the lower side in the axial direction Y of the inner circumferential surface. The middle shell 11 has a second step surface 11F0 of the second step portion 11NN, and has a first inner circumferential surface 11N1 on the upper side in the axial direction Y and a second inner circumferential surface IINO on the lower side in the axial direction Y relative to the second step portion 11NN. Therefore, an inner diameter H3 of the first inner circumferential surface 11N1 of the middle shell 11 is larger than an inner diameter H4 of the second inner circumferential surface IINO of the middle shell 11. The frame 2 has an outer circumferential surface 2G0, and a lower end surface 2F1 located on the lower side in the axial direction Y of the outer circumferential surface 2G0 and extending perpendicularly to the outer circumferential surface 2G0.

[0022] The first step surface 12F4 of the upper shell 12, the upper end surface 31F3 of the protrusion 31GG, the lower end surface 31F2 of the protrusion 31GG, the upper end surface 11F1 of the middle shell 11, the second step surface 11F0 of the second step portion 11NN of the middle shell 11, and the lower end surface 2F1 of the frame 2, are formed in parallel to each other and to the axial direction Y.

[0023] The first inner circumferential surface 12N2 of the upper shell 12, the second inner circumferential surface 12N3 of the upper shell 12, the first outer circumferential surface 31G2 of the protrusion 31GG, the second outer circumferential surface 31G1 of the fixed scroll 31, the first outer circumferential surface 11G1 of the middle shell 11, and the first inner circumferential surface 11N1 of the middle shell 11, are formed perpendicularly to the first step surface 12F4 of the upper shell 12, the upper end surface 31F3 of the protrusion 31GG, the lower end surface 31F2 of the protrusion 31GG, the upper end surface 11F1 of the middle shell 11, the second step surface 11F0 of the second step portion 11NN of the middle shell 11, and the lower end surface 2F1 of the frame 2, i.e., perpendicularly to the axial direction Y.

[0024] Regarding the fixed scroll 31, the upper end surface 31F3 of the protrusion 31GG contacts with the first step surface 12F4 of the first step portion 12NN of the upper shell 12, and the lower end surface 31F2 of the protrusion 31GG contacts with the upper end surface 11F1 in the axial direction Y of the middle shell 11, and thus the fixed scroll 31 is fixed by being clamped therebetween. The second outer circumferential surface 31G1 of the fixed scroll 31 contacts with the first inner circumferential surface 11N1 of the middle shell 11. The first inner circumferential surface 12N2 of the upper shell 12 contacts with the first outer circumferential surface 11G1 of the middle shell 11.

[0025] As described above, the upper end surface 31F3 of the protrusion 31GG and the lower end surface 31F2 of the protrusion 31GG of the fixed scroll 31 respectively contact with the first step surface 12F4 of the first step portion 12NN and the upper end surface 11F1 of the middle shell 11 of the upper shell 12, whereby their relative positions are fixed, and the compression chamber 34 is sealed in an airtight state by the second outer circumferential surface 31G1 of the fixed scroll 31 and the first inner circumferential surface 11N1 of the middle shell 11.

[0026] In order to bring the second outer circumferential surface 31G1 of the fixed scroll 31 and the first inner circumferential surface 11N1 of the middle shell 11 into contact with each other so as to seal the compression chamber 34 in an airtight state, the second outer circumferential surface 31G1 of the fixed scroll 31 is formed continuously over a range of 360 degrees in the circumferential direction along the first inner circumferential surface 11N1 of the middle shell 11. The second outer circumferential surface 31G1 of the fixed scroll 31 and the first inner circumferential surface 11N1 of the middle shell 11 are fixed to each other by shrink fit.

[0027] Since the second outer circumferential surface 31G1 of the fixed scroll 31 extends continuously over a range of 360 degrees along the first inner circumferential surface 11N1 of the middle shell 11 as described above, the second outer circumferential surface 31G1 of the fixed scroll 31 can be easily worked.

[0028] The frame 2 is fixed in contact with the second step surface 11F0 of the second step portion 11NN of the middle shell 11 and the first inner circumferential surface 11N1 of the middle shell 11. Specifically, the lower end surface 2F1 of the frame 2 contacts with the second step surface 11F0 of the second step portion 11NN of the middle shell 11, and the outer circumferential surface 2G0 of the frame 2 contacts with the first inner circumferential surface 11N1 of the middle shell 11, whereby the frame 2 is fixed.

[0029] Since the outer circumferential surface 21G0 of the frame 2 and the second outer circumferential surface 31G1 of the fixed scroll 31 contact with the same first inner circumferential surface 11N1 of the middle shell 11 so as to be fixed, high-accuracy positioning can be performed and leakage of the refrigerant can be suppressed. In addition, the middle shell 11 need not have a step for fixing the fixed scroll 31 and therefore the thickness of the middle shell 11 need not be reduced, so that the material cost and the working cost for the middle shell 11 can be reduced.

[0030] The first step surface 12F4 of the upper shell 12 is placed on the upper end surface 31F3 of the protrusion 31GG of the fixed scroll 31, and the lower end surface 12F5 of the upper shell 12 and the first outer circumferential surface 11G1 of the middle shell 11 are welded to form a welding portion 99 (see FIG. 3) and thus are fixed, whereby airtightness between the inside and the outside of the upper shell 12 and the middle shell 11 is kept. The welding portion 99 is continuously provided over the entire circumference in a range of 360 degrees in the circumferential direction along the first outer circumferential surface 11G1 of the middle shell 11.

[0031] A part where the outer circumferential surface 2G0 of the frame 2 and the first inner circumferential surface 11N1 of the middle shell 11 contact with each other is defined as a part A (see FIG. 3), and a part where the second outer circumferential surface 31G1 of the fixed scroll 31 and the first inner circumferential surface 11N1 of the middle shell 11 contact with each other is defined as a part B (see FIG. 3) . It is desirable that the position of the welding portion 99 is between the part A and the part B in the axial direction Y. When the welding portion 99 is formed at the above position, deformation of the frame 2 and the fixed scroll 31 can be suppressed and leakage of the refrigerant can be suppressed.

[0032] Regarding the welding portion 99, it is preferable that, using two or more welding torches, welding is performed in the same circumferential direction simultaneously from welding start points at not less than two positions on 180-degree opposite sides in the radial direction X. With this configuration, since fixation is performed simultaneously in initial welding from the welding start points at not less than two positions on 180-degree opposite sides, a part on a 180-degree opposite side from a welding part of the upper shell 12 can be prevented from lifting from the middle shell 11 due to thermal contraction by welding, whereby the fixed scroll 31 can be firmly fixed, so that the performance of the scroll compressor 100 is improved.

[0033] In another example, as shown in FIG. 11, the first inner circumferential surface 12N2 of the upper shell 12 has a recess 12U recessed outward in the radial direction, only at a position opposed to the first outer circumferential surface 31G2 of the fixed scroll 31. The lower end surface 31F2 in the axial direction Y of the protrusion 31GG is fixed in contact with the entirety of the upper end surface 11F1 in the axial direction Y of the middle shell 11. In the case of having the recess 12U, as compared to the case of FIG. 3, the protrusion 31GG extends more outward in the radial direction X, so that the lower end surface 31F2 of the protrusion 311GG can be fixed in contact with the entirety of the upper end surface 11F1 of the middle shell 11. Thus, as compared to the case of FIG. 3, a larger contact area at this part can be ensured.

[0034] As a method for fixing the frame 2 and the middle shell 11 of the scroll compressor 100 configured as described above, for example, the outer diameter of the outer circumferential surface 2G0 of the frame 2 is set to be larger than the inner diameter of the first inner circumferential surface 11N1 of the middle shell 11, and then fixation is performed by shrink fit or cooling fit. Alternatively, the middle shell 11 and the frame 2 are fixed by piercing welding using a laser beam or the like. Alternatively, a hole is formed in the middle shell 11 at a position corresponding to the frame 2, and fixation is performed by welding the hole. Alternatively, the frame 2 is fixed by being press-fitted from the upper side to the lower side (from U side to L side) in the axial direction Y of the middle shell 11. A method for fixing the middle shell 11 and the frame 2 is not limited to the above methods.

[0035] As a method for fixation and airtight sealing between the fixed scroll 31 and the middle shell 11, for example, the outer diameter of the second outer circumferential surface 31G1 of the fixed scroll 31 is set to be larger than the inner diameter of the first inner circumferential surface 11N1 of the middle shell 11, and fixation is performed by shrink fit or cooling fit. Alternatively, the middle shell 11 and the fixed scroll 31 may be fixed by piercing welding using a laser beam or the like. Alternatively, the fixed scroll 31 may be press-fitted from the upper side to the lower side (from U side to L side) in the axial direction Y of the middle shell 11, whereby the fixed scroll 31 is fixed to the middle shell 11. A method for fixation and airtight sealing between the middle shell 11 and the fixed scroll 31 is not limited to the above methods.

[0036] In the above example, the compression chamber 34 is sealed in an airtight state by the second outer circumferential surface 31G1 of the fixed scroll 31 and the first inner circumferential surface 11N1 of the middle shell 11. However, for example, airtightness of the compression chamber 34 may be kept by the lower end surface 31F2 of the protrusion 31GG of the fixed scroll 31 and the upper end surface 11F1 of the middle shell 11. In this case, it is desirable that a sealing material is interposed between the lower end surface 31F2 of the protrusion 31GG of the fixed scroll 31 and the upper end surface 11F1 of the middle shell 11.

[0037] Next, a configuration example for keeping airtightness on the U side and the L side of the fixed scroll 31 will be described with reference to FIG. 4 which is an enlarged view showing another example of the part enclosed by the dotted line S2 in the scroll compressor 100 shown in FIG. 2. For example, the second outer circumferential surface 31G1 of the fixed scroll 31 is shrink-fitted or cooling-fitted to the first inner circumferential surface 11N1 of the middle shell 11, or a welding portion 201 is formed at a contact point between the middle shell 11 and the fixed scroll 31 by laser welding or the like, whereby airtightness on the U side and the L side of the fixed scroll 31 is kept.

[0038] In addition, a recess is formed at the first outer circumferential surface 31G2 of the fixed scroll 31, and a sealing portion 202 such as an 0 ring is provided in the recess, whereby airtightness on the U side and the L side of the fixed scroll 31 is kept.

[0039] In order to avoid interference, it is preferable that corners shown below are chamfered or rounded. ■ A corner at the boundary between the first step surface 12F4 and the second inner circumferential surface 12N3 of the upper shell 12 ■ A corner at the boundary between the lower end surface 12F5 of the upper shell 12 and an outer circumferential surface 12G1 of the upper shell 12 • A corner at the boundary between the upper end surface 31F3 of the protrusion 31GG and the first outer circumferential surface 31G2 of the protrusion 31GG of the fixed scroll 31 ■ A corner at the boundary between the lower end surface 31F2 of the protrusion 31GG and the first outer circumferential surface 31G2 of the protrusion 31GG of the fixed scroll 31 • A corner at the boundary between the second outer circumferential surface 31G1 of the fixed scroll 31 and a lower end surface 31F4 of the fixed scroll 31 • A corner at the boundary between the upper end surface 11F1 of the middle shell 11 and the first inner circumferential surface 11N1 of the middle shell 11 • A corner at the boundary between the upper end surface 11F1 of the middle shell 11 and the first outer circumferential surface 11G1 of the middle shell 11 ■ A corner at the boundary between the second step surface 11F0 of the middle shell 11 and the second inner circumferential surface IINO of the middle shell 11 ■ A corner at the boundary between the outer circumferential surface 2G0 of the frame 2 and the lower end surface 2F1 of the frame 2 • A corner at the boundary between the outer circumferential surface 2G0 of the frame 2 and a U-side surface adjacent to the outer circumferential surface 2G0

[0040] In fixing the fixed scroll 31 to the middle shell 11, it is necessary to determine the phase of the fixed scroll 31 relative to the frame 2. As a method for determining the phase, the fixed scroll 31 and the middle shell 11 may be provided with pin holes and may be fixed with a pin .

[0041] The protrusion 31GG of the fixed scroll 31 need not be formed continuously over a range of 360 degrees in the circumferential direction along the first inner circumferential surface 12N2 of the upper shell 12. Another example will be described with reference to FIG. 5. As shown in FIG. 5A, for example, the protrusion 31GG is formed intermittently along the first inner circumferential surface 12N2 of the upper shell 12 so as to be divided into four parts. The fixed scroll 31 includes a first protrusion 31GA, a second protrusion 31GB, a third protrusion 31GC, and a fourth protrusion 31GD which have the first outer circumferential surfaces 31G2 having the outer diameter W1 larger than the outer diameter W2 of the second outer circumferential surface 31G1.

[0042] In the radial direction X of the fixed scroll 31, recesses are formed between the first protrusion 31GA, the second protrusion 31GB, the third protrusion 31GC, and the fourth protrusion 31GD. The recesses are formed by a die in casting or forging, or by cutting, etc. In the case where the protrusion 31GG is divided into, for example, the first protrusion 31GA, the second protrusion 31GB, the third protrusion 31GC, and the fourth protrusion 31GD as described above, a part where the fixed scroll 31 is subjected to a force via the upper shell 12 when the welding portion 99 is contracted can be controlled, and if recesses are formed near the pin hole for determining the phase for the frame 2 and the fixed scroll 31, a load is less applied around the pin hole. Thus, deformation of the pin hole is suppressed and phase shift between the frame 2 and the fixed scroll 31 is suppressed, so that the performance of the scroll compressor 100 is improved.

[0043] In Patent Document 1, the center shell and the lid cap are welded, whereby the fixed scroll is fixed with the fixed scroll and the frame clamped between the end surface of the center shell and the lid cap. In this case, the welding is performed so as to draw a circumference from a start point. At a position closer to the start point, the center shell and the lid cap are less fixed and therefore thermal contraction due to welding is great. At a position closer to a finish point, thermal contraction is small because of constraint by a welding portion near the start point. A 180-degree opposite side of the lid cap lifts from the fixed scroll due to thermal contraction near the start point, so that a gap between the orbiting scroll and the fixed scroll becomes large and the compressed refrigerant leaks, resulting in reduction in the performance of the scroll compressor.

[0044] On the other hand, in the present embodiment configured as described above, as compared to the conventional case, the number of fixation locations increases, and only the fixed scroll 31 is clamped, whereby the fixed scroll 31 can be firmly fixed. Thus, lifting of the fixed scroll 31 is suppressed and a gap between the orbiting scroll 32 and the fixed scroll 31 can be kept small, whereby reduction in the performance of the scroll compressor 100 can be suppressed.

[0045] The scroll compressor according to embodiment 1 configured as described above includes: an orbiting scroll; a frame retaining the orbiting scroll slidably; a fixed scroll forming a compression chamber together with the orbiting scroll; a middle shell storing the frame, the orbiting scroll, and the fixed scroll; and an upper shell sealing an upper side of the fixed scroll on the middle shell. The fixed scroll has a protrusion protruding outward in a radial direction between outer circumferential surfaces in an axial direction and having a first outer circumferential surface, and a second outer circumferential surface on a lower side in the axial direction relative to the protrusion. The upper shell has a first step portion where an inner diameter is increased on a lower side in the axial direction, at an inner circumferential surface on the middle shell side. The fixed scroll is fixed such that an upper end surface in the axial direction of the protrusion contacts with a first step surface of the first step portion of the upper shell and a lower end surface in the axial direction of the protrusion contacts with an upper end surface in the axial direction of the middle shell. The second outer circumferential surface of the fixed scroll is formed in contact with a first inner circumferential surface on an upper side in the axial direction of the middle shell. A first inner circumferential surface on a lower side in the axial direction of the first step portion of the upper shell is formed in contact with a first outer circumferential surface on an upper side in the axial direction of the middle shell. Thus, since the fixed scroll can be fixed by the middle shell and the upper shell, it becomes unnecessary to additionally form an outer peripheral wall and the like at the frame, and a large formation area for the orbiting scroll can be ensured. Therefore, it is possible to increase the compression volume for the refrigerant without increasing the size of the apparatus. In addition, since only the fixed scroll is clamped between the middle shell and the upper shell, a fixation force for the fixed scroll can be increased as compared to the conventional case, whereby a gap between the orbiting scroll and the fixed scroll can be kept small, and thus the performance of the scroll compressor is improved. Further, displacement of the fixed scroll is reduced, so that leakage of the refrigerant is suppressed, leading to improvement in performance.

[0046] An outer diameter of the first outer circumferential surface of the fixed scroll is smaller than an inner diameter of a first inner circumferential surface on a lower side of the first step portion of the upper shell. Thus, the upper shell can be easily attached to the middle shell.

[0047] The middle shell has a second step portion where an inner diameter is reduced, on a lower side in the axial direction relative to the first inner circumferential surface of the middle shell, and the frame is fixed in contact with a second step surface of the second step portion of the middle shell and the first inner circumferential surface of the middle shell. Thus, a gap between the orbiting scroll and the fixed scroll can be controlled with high accuracy, whereby leakage of the refrigerant is reduced, the performance of the scroll compressor is improved, and working is facilitated.

[0048] The second outer circumferential surface of the fixed scroll is formed continuously over a range of 360 degrees in a circumferential direction, and the second outer circumferential surface of the fixed scroll and the first inner circumferential surface of the middle shell are fixed to each other by shrink fit. Thus, the fixation force of the fixed scroll increases and displacement of the fixed scroll is further reduced, so that leakage of the refrigerant is further suppressed, the performance is further improved, and working is further facilitated.

[0049] A welding portion is formed so that a lower end surface in the axial direction of the upper shell and the middle shell are welded and fixed at a position on a lower side in the axial direction relative to the upper end surface of the middle shell. Thus, owing to a contraction force of welding, the force for clamping the fixed scroll increases. In addition, through contraction of the welding portion, the fixed scroll is pressed to the upper end surface of the middle shell via the first step surface of the upper shell, whereby the fixed scroll can be fixed to the middle shell. As compared to the conventional case, the number of fixation locations increases, and only the fixed scroll 31 is clamped, whereby the fixed scroll can be firmly fixed. Thus, lifting of the fixed scroll is suppressed and a gap between the orbiting scroll and the fixed scroll can be kept small, whereby reduction in the performance of the scroll compressor pAn bp <51innkpq qoH ex. x x ev e*- kJ ex p— pJ J— e kJ kJ e*- ex. •

[0050] Further, a part where the pressure is high can be enclosed by the upper shell and the fixed scroll, and the middle shell only includes a low-pressure part. Thus, a load on the middle shell due to the refrigerant internal pressure can be reduced. Accordingly, reliability of the scroll compressor can be enhanced or the cost can be reduced by reducing the thickness of the middle shell. In addition, a bolt is not needed for fixation of the fixed scroll, and therefore the number of components can be decreased.

[0051] The first inner circumferential surface of the upper shell has a recess recessed outward in the radial direction, only at a position opposed to the first outer circumferential surface of the fixed scroll, and the lower end surface in the axial direction of the protrusion is fixed in contact with an entirety of the upper end surface in the axial direction of the middle shell. Thus, a large contact area can be ensured between the lower end surface in the axial direction of the protrusion and the upper end surface in the axial direction of the middle shell, whereby the fixed scroll can be prevented from having contact on only one side and the retention force for the fixed scroll increases. In addition, in manufacturing, the fixed scroll can be easily placed at the upper end surface of the middle shell.

[0052] Embodiment 2 FIG. 6 is a partial sectional view showing a configuration of a scroll compressor according to embodiment 2. A scroll compressor 100 according to the present embodiment 2 will be described with reference to FIG. 6. In FIG. 6, the same parts as those in the above embodiment 1 are denoted by the same reference characters. In the present embodiment 2, the description of the same parts as those in the above embodiment 1 is omitted as appropriate, and parts different from the above embodiment 1 will be mainly described.

[0053] As shown in FIG. 6, the first outer circumferential surface 31G2 of the protrusion 31GG of the fixed scroll 31 has a first groove 88 recessed in the radial direction X. The first groove 88 does not fully penetrate in the radial direction X. It is desirable that the first groove 88 is formed continuously over a range of 360 degrees in the circumferential direction along the first outer circumferential surface 31G2 of the protrusion 31GG, but the configuration of the first groove 88 is not limited thereto. It is preferable that a position D88 in the radial direction X of the bottom surface of the first groove 88 is on the inner side in the radial direction X relative to a position LI in the radial direction X of the second inner circumferential surface 12N3 of the upper shell 12.

[0054] The lower end surface 31F4 of the fixed scroll 31 has a second groove 89 recessed upward in the axial direction Y, on the outer side in the radial direction X relative to a scroll wrap 311 of the scroll compressor 100. The second groove 89 does not fully penetrate through the fixed scroll 31 in the axial direction Y. It is desirable that the second groove 89 is formed continuously over a range of 360 degrees in the circumferential direction in the lower end surface 31F4 of the fixed scroll 31, but the configuration of the second groove 89 is not limited thereto. It is preferable that a position D89 in the axial direction Y of the bottom surface of the second groove 89 is on the upper side in the axial direction Y relative to a position D87 in the axial direction Y of the lower end surface 31F2 of the protrusion 31GG of the fixed scroll 31.

[0055] In the case where the fixed scroll 31 is formed as described above, when the welding portion 99 is formed to weld and fix the lower end surface 12F5 of the upper shell 12 and the first outer circumferential surface 11G1 of the middle shell 11, the welding portion 99 is contracted, so that the second outer circumferential surface 31G1 of the fixed scroll 31 is subjected to mainly a force inward in the radial direction X via the first inner circumferential surface 11N1 of the middle shell 11, and the upper end surface 31F3 of the protrusion 31GG of the fixed scroll 31 is subjected to mainly a force upward in the axial direction Y via the first step surface 12F4 of the upper shell 12.

[0056] The first groove 88 and the second groove 89 are provided correspondingly to the above forces, whereby parts between each groove 88, 89 and a portion subjected to the force is greatly deformed intentionally, so that deformation of a center part (center part in the axial direction Y and the radial direction X) of the fixed scroll 31 can be suppressed. Since the pressure in the center part of the fixed scroll 31 becomes high, the compressed refrigerant is likely to leak through a gap between the fixed scroll 31 and the orbiting scroll 32. However, since deformation of the center part of the fixed scroll 31 is suppressed, a gap between the orbiting scroll 32 and the fixed scroll 31 can be kept small, whereby reduction in the performance of the scroll compressor 100 can be suppressed.

[0057] In addition, since the temperature in the center part of the fixed scroll 31 becomes high, the expansion amount of the center part is large and the orbiting scroll 32 and the fixed scroll 31 are pressed to each other. When the expansion amount is large, the scrolls cannot slide and seizure occurs, resulting in malfunction. However, since deformation of the center part of the fixed scroll 31 is suppressed, a proper clearance can be kept and thus malfunction can be prevented.

[0058] In the scroll compressor according to embodiment 2 configured as described above, the same effects as in the above embodiment 1 are provided, and in addition, the first outer circumferential surface of the fixed scroll has a first groove recessed in the radial direction. Thus, a force applied inward in the radial direction to the second outer circumferential surface of the fixed scroll via the first inner circumferential surface of the middle shell is inhibited by the first groove, whereby deformation of the fixed scroll is suppressed.

[0059] A lower end surface in the axial direction of the fixed scroll has a second groove recessed upward in the axial direction, on an outer side in the radial direction relative to a scroll wrap of the scroll compressor. Thus, a force applied mainly upward in the axial direction to the upper end surface of the protrusion of the fixed scroll via the first step surface of the upper shell is inhibited by the second groove, whereby deformation of the fixed scroll is suppressed.

[0060] Embodiment 3 FIG. 7 is a partial sectional view showing a configuration of a scroll compressor according to embodiment 3. A scroll compressor 100 according to the present embodiment 3 will be described with reference to FIG. 7. In FIG. 7, the same parts as those in the above embodiments are denoted by the same reference characters. In the present embodiment 3, the description of the same parts as those in the above embodiments is omitted as appropriate, and parts different from the above embodiments will be mainly Hpqr r 1 "hpiH d kJ _L_ —I— d •

[0061] As shown in FIG. 7, the middle shell 11 has a second step portion 11NN where the inner diameter of the first inner circumferential surface 11N1 of the middle shell 11 is reduced, at the inner circumferential surface on the lower side in the axial direction Y, and has a third step portion 11NM where the inner diameter of the first inner circumferential surface 11N1 is reduced, at the inner circumferential surface between the fixed scroll 31 and the frame 2 and on the upper side in the axial direction Y relative to the second step portion 11NN.

[0062] A third inner circumferential surface 11N11 is formed on the upper side in the axial direction Y relative to the second step surface 11F0 of the second step portion 11NN of the middle shell 11 and on the lower side in the axial direction Y relative to a third step surface 11F11 of the third step portion 11NM.

[0063] The frame 2 is fixed in contact with the second step surface 11F0 of the second step portion 11NN of the middle shell 11 and the third inner circumferential surface 11N11 of the middle shell 11. Specifically, the lower end surface 2F1 of the frame 2 contacts with the second step surface 11F0 of the second step portion 11NN of the middle shell 11, and the outer circumferential surface 2G0 of the frame 2 contacts with the third inner circumferential surface 11N11 of the middle shell 11, whereby the frame 2 is fixed.

[0064] As a fixation method, for example, the outer diameter of the outer circumferential surface 2G0 of the frame 2 is set to be larger than the inner diameter of the third inner circumferential surface 11N11 of the middle shell 11, and then shrink fit or cooling fit is performed. Alternatively, piercing welding is performed for the middle shell 11 and the frame 2 by a laser beam or the like. Alternatively, a hole may be formed in the middle shell 11 at a position corresponding to the frame 2, and the middle shell 11 and the frame 2 may be fixed by welding the hole.

[0065] Alternatively, the frame 2 may be press-fitted from the upper side to the lower side (from U side to L side) in the axial direction Y of the middle shell 11, whereby the middle shell 11 is fixed to the frame 2. A method for fixing the frame 2 to the middle shell 11 is not limited to the above methods.

[0066] The second outer circumferential surface 31G1 of the fixed scroll 31 contacts with the first inner circumferential surface 11N1 of the middle shell 11, the lower end surface 31F2 of the protrusion 31GG of the fixed scroll 31 contacts with the upper end surface 11F1 of the middle shell 11, and the upper end surface 31F3 of the protrusion 31GG of the fixed scroll 31 contacts with the first step surface 12F4 of the first step portion 12NN of the upper shell 12, whereby the fixed scroll 31 is fixed. Therefore, the fixed scroll 31 does not contact with the third step surface 11F11 of the third step portion 11NM and the third inner circumferential surface 11N11 of the middle

[0067] As a fixation method, for example, the outer diameter of the second outer circumferential surface 31G1 is set to be greater than the inner diameter of the first inner circumferential surface 11N1 of the middle shell 11, and then the fixed scroll 31 is shrink-fitted or cooling-fitted. Alternatively, the middle shell 11 and the fixed scroll 31 may be fixed by piercing welding using a laser beam or the

[0068] The fixed scroll 31 may be press-fitted from the upper side to the lower side (from U side to L side) in the axial direction Y of the middle shell 11, whereby the fixed scroll 31 is fixed to the middle shell 11. A method for fixing the fixed scroll 31 to the middle shell 11 is not limited to the above methods.

[0069] It is preferable that two surfaces shown below are formed by machining. If these surfaces are formed by machining, control can be performed with high accuracy, and thus a gap between the orbiting scroll 32 and the fixed scroll 31 can be kept small, whereby the performance of the scroll compressor 100 is improved. ■ The third inner circumferential surface 11N11 whose inner diameter is smaller than the inner diameter of the first inner circumferential surface 11N1 of the middle shell 11 and the outer diameter of the second outer circumferential surface 31G1 of the fixed scroll 31 ■ The third step surface 11F11 which is perpendicular to the third inner circumferential surface 11N11 of the middle shell 11 and parallel to the upper end surface 11F1 of the middle shell 11 and is located between the first inner circumferential surface 11N1 of the middle shell 11 and the third inner circumferential surface 11N11 of the middle shell 11

[0070] In the case of fixing the frame 2 and the fixed scroll 31 to the middle shell 11 by shrink fit or cooling fit as described above, since the inner diameter Hl (see FIG. 2) of the first inner circumferential surface 11N1 of the middle shell 11 at which the fixed scroll 31 is fixed is larger than an inner diameter Hll of the third inner circumferential surface 11N11 of the middle shell 11 at which the frame 2 is fixed, the fixed scroll 31 can be shrink-fitted or cooling-fitted with a smaller temperature difference in heating or cooling than the frame 2. Thus, the fixed scroll 31 can be fixed to the middle shell 11 with lower energy.

[0071] In the case of fixing the frame 2 and the fixed scroll 31 to the middle shell 11 by press fit, fixation of the frame 2 and the fixed scroll 31 is performed using the third inner circumferential surface 11N11 of the middle shell 11 and the first inner circumferential surface 11N1 different from the third inner circumferential surface 11N11, whereby the fixed scroll 31 can be more firmly fixed to the middle shell 11, and since a scar due to sliding is less formed, airtightness is improved.

[0072] In order to avoid interference, it is preferable that, in addition to the corners described in the above embodiments, a corner shown below is chamfered or rounded. • A corner at the boundary between the third step surface 11F11 of the third step portion 11NM of the middle shell 11 and the third inner circumferential surface 11N11 of the middle shell 11

[0073] It is preferable that three surfaces shown below are formed by machining. If these surfaces are formed by machining, control can be performed with high accuracy, and thus a gap between the orbiting scroll 32 and the fixed scroll 31 can be kept small, whereby the performance of the scroll compressor 100 is improved. • The upper end surface 11F1 at the upper end in the axial direction Y of the middle shell 11 ■ The first inner circumferential surface 11N1 perpendicular to the upper end surface 11F1 of the middle shell 11 ■ The second step surface 11F0 of the second step portion 11NN of the middle shell 11

[0074] In the scroll compressor according to embodiment 3 configured as described above, the same effects as in the above embodiments are provided, and in addition, the middle shell has a second step portion where an inner diameter is reduced, on a lower side in the axial direction relative to the first inner circumferential surface of the middle shell, and a third step portion where an inner diameter is reduced, at an inner circumferential surface between the fixed scroll and the frame and on an upper side in the axial direction relative to the second step portion. The frame is fixed in contact with a second step surface of the second step portion of the middle shell and a third inner circumferential surface on an upper side in the axial direction of the second step portion and a lower side in the axial direction of the third step portion of the middle shell. Thus, in a case of fixing the frame and the fixed scroll to the middle shell by shrink fit or cooling fit, since the inner diameter of the first inner circumferential surface of the middle shell at which the fixed scroll is fixed is larger than the inner diameter of the third inner circumferential surface of the middle shell at which the frame is fixed, the fixed scroll can be shrink-fitted or cooling-fitted with a smaller temperature difference in heating or cooling than the frame. Thus, the fixed scroll can be fixed to the middle shell with lower energy.

[0075] In the case of fixing the frame and the fixed scroll to the middle shell by pressure, fixation of the frame and the fixed scroll is performed using the third inner circumferential surface of the middle shell and the first inner circumferential surface different from the third inner circumferential surface, whereby the fixed scroll can be more firmly fixed to the middle shell, and since a scar due to sliding is less formed, airtightness is improved.

[0076] Embodiment 4 FIG. 8 is a partial sectional view showing a configuration of a scroll compressor according to embodiment 4. FIG. 9 is a partial sectional view showing a configuration of the scroll compressor shown in FIG. 8. FIG. 10 is a partial sectional view showing a configuration of a scroll compressor in a comparative example. A scroll compressor 100 according to the present embodiment 4 will be described with reference to FIG. 8. In FIG. 8, the same parts as those in the above embodiments are denoted by the same reference characters. In the present embodiment 4, the description of the same parts as those in the above embodiments is omitted as appropriate, and parts different from the above embodiments will be mainly described.

[0077] As shown in FIG. 8, the inner diameter H2 of the second inner circumferential surface 12N3 of the upper shell 12 is set to be equal to or larger than the inner diameter H3 of the first inner circumferential surface 11N1 of the middle shell 11. Regarding the inner diameter H2 and the inner diameter H3, see FIG. 2.

[0078] In this configuration, when the welding portion 99 is contracted, as shown in FIG. 9, the fixed scroll 31 is subjected to mainly a force Fl directed from the upper side to the lower side (from U side to L side) in the axial direction Y via the first step surface 12F4 of the upper shell 12. In a contact range between the first step surface 12F4 of the upper shell 12 and the upper end surface 31F3 of the protrusion 31GG of the fixed scroll 31, the fixed scroll 31 is subjected to a force F2 directed from the upper side to the lower side (from U side to L side) in the axial direction Y in the same manner as described above.

[0079] The lower side (L side) in the axial direction Y of the above contact range is supported by the upper end surface 11F1 of the middle shell 11. Therefore, as shown in FIG. 9, the inner diameter H2 of the second inner circumferential surface 12N3 of the upper shell 12 is set to be equal to the inner diameter H3 of the first inner circumferential surface 11N1 of the middle shell 11, whereby, as compared to a case shown in the comparative example in FIG. 10, the part subjected to a force from the upper shell 12 can be made close to the support part of the middle shell 11, so that deformation of the fixed scroll 31 can be suppressed.

[0080] In the scroll compressor according to embodiment 4 configured as described above, the same effects as in the above embodiments are provided, and in addition, an inner diameter of a second inner circumferential surface on an upper side in the axial direction of the first step portion of the upper shell is equal to or larger than an inner diameter of the first inner circumferential surface of the middle shell. Thus, the part subjected to a force from the upper shell can be made close to the support part of the middle shell, so that deformation of the fixed scroll can be suppressed.

[0081] Embodiment 5 FIG. 12 is a partial sectional view showing a configuration of a scroll compressor according to embodiment 5. FIG. 13 shows the relationship between a formation position of a welding portion and deformation amounts of a fixed scroll and a frame, in the scroll compressor according to embodiment 5. A scroll compressor 100 according to the present embodiment 5 will be described with reference to FIG. 12. In FIG. 12, the same parts as those in the above embodiments are denoted by the same reference characters. In the present embodiment 5, the description of the same parts as those in the above embodiments is omitted as appropriate, and parts different from the above embodiments will be mainly described.

[0082] In the present embodiment 5, a position where the welding portion 99 is formed will be described. As shown in FIG. 12, a distance from the upper end surface 31F3 of the fixed scroll 31 which contacts with the first step surface 12F4 of the upper shell 12 to the lower end surface 12F5 of the upper shell 12 at which the welding portion 99 is formed, is defined as a first distance Tl. A distance from the lower end surface 12F5 of the upper shell 12 at which the welding portion 99 is formed to an upper end surface 2F0 of the frame 2, is defined as a second distance T2. The ratio of the first distance Tl and the second distance T2 is determined on the basis of rigidity of the fixed scroll 31 and rigidity of the frame 2.

[0083] As shown in FIG. 13, the horizontal axis indicates the position where the welding portion 99 is formed, in a range from the position of the upper end surface 31F3 in the axial direction Y of the protrusion 31GG of the fixed scroll 31 to the position of the upper end surface 2F0 of the frame 2. The vertical axis indicates the deformation amount of the fixed scroll 31 and the deformation amount of the frame 2. As shown in FIG. 13, regarding the formation position of the welding portion 99, it can be confirmed that, as the first distance Tl becomes longer, the deformation amount of the fixed scroll 31 becomes smaller and the deformation amount of the frame 2 becomes larger.

[0084] Therefore, the ratio of the first distance Tl and the second distance T2 is determined in consideration of rigidity of the fixed scroll 31 and rigidity of the frame 2, whereby it is possible to determine the formation position of the welding portion 99 that can most suppress the deformation amounts of the fixed scroll 31 and the frame 2. As a method for determining the ratio of the first distance T1 and the second distance T2, for example, the ratio of the first distance T1 and the second distance T2 is set to be opposite to the ratio of the rigidities so that the deformation amount of the fixed scroll 31 and the deformation amount of the frame 2 become the same (e.g., a position of an intersection Q in FIG. 13). This is merely an example, and in accordance with performance required for the scroll compressor 100, the formation position of the welding portion 99 is set as appropriate on the basis of rigidity of the fixed scroll 31 and rigidity of the frame 2.

[0085] In the scroll compressor according to embodiment 5 configured as described above, the same effects as in the above embodiment 1 are provided, and in addition, on the basis of rigidity of the frame and rigidity of the fixed scroll, a first distance from the upper end surface of the fixed scroll to the lower end surface of the upper shell, and a second distance from an upper end surface in the axial direction of the frame to the lower end surface of the upper shell, are determined, and thus a position of the welding portion is determined. Thus, it is possible to determine a formation position of the welding portion that can optimally suppress the deformation amount of the fixed scroll and the deformation amount of the frame.

[0086] Embodiment 6 FIG. 14 is a partial sectional view showing a configuration of a scroll compressor according to embodiment 6. FIG. 15 is an enlarged view of a part enclosed by a dotted line S3 in the scroll compressor shown in FIG. 14. A scroll compressor 100 according to the present embodiment 6 will be described with reference to FIG. 14 and FIG. 15. In FIG. 14 and FIG. 15, the same parts as those in the above embodiments are denoted by the same reference characters. In the present embodiment 6, the description of the same parts as those in the above embodiments is omitted as appropriate, and parts different from the above embodiments will be mainly H tA Gz -I— —I— ry z •

[0087] As shown in FIG. 14 and FIG. 15, the middle shell 11 has a fourth step portion 11NP where the outer diameter is increased, on the lower side in the axial direction Y relative to the first outer circumferential surface 11G1 of the middle shell 11. An outer circumference of the middle shell 11 on the lower side in the axial direction Y relative to the fourth step portion 11NP of the middle shell 11 forms a second outer circumferential surface 11G2. The lower end surface 12F5 in the axial direction Y of the upper shell 12 is located so as to be opposed to a fourth step surface 11F2 of the fourth step portion 11NP of the middle shell 11 with a gap P (see FIG. 15) therebetween.

[0088] Since the first step surface 12F4 of the upper shell 12 and the upper end surface 31F3 of the fixed scroll 31 contact with each other, the lower end surface 12F5 of the upper shell 12 and the fourth step surface 11F2 of the middle shell are difficult to contact with each other and therefore the gap P is formed. The welding portion 99 (see FIG. 15) is formed in the gap P. As a method for forming the welding portion 99, low strain welding such as laser welding can be used. It is also possible that the welding portion 99 is not formed.

[0089] In FIG. 14 and FIG. 15, the gap P is shown in a large size exaggeratedly so as to be clarified. However, the gap P is formed to be as narrow as possible, and the outer circumferential surface 12G1 of the upper shell 12 and the second outer circumferential surface 11G2 on the lower side in the axial direction Y relative to the fourth step portion 11NP of the middle shell 11 are formed approximately contiguously. The upper shell 12 has a tube portion 121 which opens on the middle shell 11 side, and a bottom portion 122 connecting to the tube portion 121 on the side opposite to the middle shell 11 side in the axial direction Y, and the upper shell 12 has a heated mark 200 due to heating, on the upper side in the axial direction Y of the tube portion 121.

[0090] The reason why the above part is heated to form the heated mark 200 will be described. As shown in FIG. 15, when the welding portion 99 is formed in the gap P between the lower end surface 12F5 of the upper shell 12 and the fourth step surface 11F2 of the middle shell, the welding portion 99 is formed locally with respect to the entire plate thickness area between the upper shell 12 and the middle shell 11. Therefore, the upper shell 12 and the middle shell 11 locally undergo contractive deformation due to compression in the vicinity of the welding portion 99, so that the upper shell 12 and the middle shell 11 deform so as to bend laterally around the welding portion 99 (deformation as indicated by a dotted line in FIG. 15). This is a state in which angular distortion has occurred in the upper shell 12 and the middle shell 11. In order to suppress the angular distortion, an upper part of the tube portion 121 of the upper shell 12 is heated, whereby the distortion is suppressed. As a result, the heated mark 200 is left there.

[0091] In the scroll compressor according to embodiment 5 configured as described above, the same effects as in the above embodiments are provided, and in addition, the middle shell has a fourth step portion where an outer diameter is increased, on a lower side in the axial direction relative to the first outer circumferential surface of the middle shell, and a lower end surface in the axial direction of the upper shell is located so as to be opposed to a fourth step surface of the fourth step portion of the middle shell with a gap therebetween. Thus, the upper shell and the fixed scroll can assuredly contact with each other, so that the fixation strength of the fixed scroll increases.

[0092] The upper shell has a tube portion which opens on the middle shell side, and a bottom portion connecting to the tube portion on a side opposite to the middle shell side in the axial direction, and a heated mark due to heating is formed on an upper side in the axial direction of the tube portion . Thus, angular distortion of the upper shell and the middle shell can be suppressed.

[0093] In the above description, the wordings "perpendicular", "parallel", or "same / equal" mean "perpendicular", "parallel", or "same / equal" in a common sense of a person skilled in the art in manufacturing of the scroll compressor 100, and include "substantially perpendicular", "substantially parallel", or "substantially same / equal" within a common-sense scope for a person skilled in the art.

[0094] Although the disclosure is described above in terms of various exemplary embodiments and implementations, it should be understood that the various features, aspects, and functionality described in one or more of the individual embodiments are not limited in their applicability to the particular embodiment with which they are described, but instead can be applied, alone or in various combinations to one or more of the embodiments of the disclosure. It is therefore understood that numerous modifications which have not been exemplified can be devised without departing from the scope of the present disclosure. For example, at least one of the constituent components may be modified, added, or eliminated. At least one of the constituent components mentioned in at least one of the preferred embodiments may be selected and combined with the constituent components mentioned in another preferred embodiment.

[0095] Hereinafter, modes of the present disclosure are summarized as additional notes.

[0096] (Additional note 1) A scroll compressor comprising: an orbiting scroll; a frame retaining the orbiting scroll slidably; a fixed scroll forming a compression chamber together with the orbiting scroll; a middle shell storing the frame, the orbiting scroll, and the fixed scroll; and an upper shell sealing an upper side of the fixed scroll on the middle shell, wherein the fixed scroll has a protrusion protruding outward in a radial direction between outer circumferential surfaces in an axial direction and having a first outer circumferential surface, and a second outer circumferential surface on a lower side in the axial direction relative to the protrusion, the upper shell has a first step portion where an inner diameter is increased on a lower side in the axial direction, at an inner circumferential surface on the middle shell side, the fixed scroll is fixed such that an upper end surface in the axial direction of the protrusion contacts with a first step surface of the first step portion of the upper shell and a lower end surface in the axial direction of the protrusion contacts with an upper end surface in the axial direction of the middle shell, and the second outer circumferential surface of the fixed scroll is formed in contact with a first inner circumferential surface on an upper side in the axial direction of the middle shell. (Additional note 2) The scroll compressor according to additional note 1, wherein an outer diameter of the first outer circumferential surface of the fixed scroll is smaller than an inner diameter of a first inner circumferential surface on a lower side of the first step portion of the upper shell. (Additional note 3) The scroll compressor according to additional note 1 or 2, wherein the middle shell has a second step portion where an inner diameter is reduced, on a lower side in the axial direction relative to the first inner circumferential surface of the middle shell, and the frame is fixed in contact with a second step surface of the second step portion of the middle shell and the first inner circumferential surface of the middle shell. (Additional note 4) The scroll compressor according to additional note 1 or 2, wherein the middle shell has a second step portion where an inner diameter is reduced, on a lower side in the axial direction relative to the first inner circumferential surface of the middle shell, and a third step portion where an inner diameter is reduced, at an inner circumferential surface between the fixed scroll and the frame and on an upper side in the axial direction relative to the second step portion, and the frame is fixed in contact with a second step surface of the second step portion of the middle shell and a third inner circumferential surface on an upper side in the axial direction of the second step portion and a lower side in the axial direction of the third step portion of the middle shell. (Additional note 5) The scroll compressor according to any one of additional notes 1 to 4, wherein the second outer circumferential surface of the fixed scroll is formed continuously over a range of 360 degrees in a circumferential direction, and the second outer circumferential surface of the fixed scroll and the first inner circumferential surface of the middle shell are fixed to each other by shrink fit. (Additional note 6) The scroll compressor according to any one of additional notes 1 to 5, wherein a welding portion is formed so that a lower end surface in the axial direction of the upper shell and an outer circumferential surface of the middle shell are welded and fixed at a position on a lower side in the axial direction relative to the upper end surface of the middle shell. The scroll compressor according to any one of additional notes 1 to 6, wherein an inner diameter of a second inner circumferential surface on an upper side in the axial direction of the first step portion of the upper shell is equal to an inner diameter of the first inner circumferential surface of the middle shell. (Additional note 8) The scroll compressor according to any one of additional notes 1 to 7, wherein the first outer circumferential surface of the fixed scroll has a first groove recessed in the radial direction. (Additional note 9) The scroll compressor according to any one of additional notes 1 to 8, wherein a lower end surface in the axial direction of the fixed scroll has a second groove recessed upward in the axial direction, on an outer side in the radial direction relative to a scroll wrap of the scroll compressor. DESCRIPTION OF THE REFERENCE CHARACTERS

[0097] 1 shell 100 scroll compressor 11 middle shell 11F0 second step surface 11F1 upper end surface 11F2 fourth step surface 11F11 third step surface 11G1 first outer circumferential surface 11G2 second outer circumferential surface IINO second inner circumferential surface 11N1 first inner circumferential surface 11NN second step portion 11NP fourth step portion 12 upper shell 12U 220 cq s s 121 tube portion 122 bottom portion 12N2 first inner circumferential surface 12NN first step portion 12F4 first step surface 12F5 lower end surface 12G1 outer circumferential surface 12N3 second inner circumferential surface 13 lower shell 15 discharge pipe 2 frame 2F1 lower end surface 2G0 outer circumferential surface 20 bearing 201 welding portion 202 sealing portion 31 fixed scroll 31F3 upper end surface 31F2 lower end surface 31F4 lower end surface 31G1 second outer circumferential surface 31G2 first outer circumferential surface 31GA first protrusion 31GB second protrusion 31GC third protrusion 31GD fourth protrusion 31GG protrusion 32 orbiting scroll 34 compression chamber 311 scroll wrap 4 driving portion 50 sub frame 6 crankshaft 62 eccentric shaft portion 99 welding portion Hl inner diameter H2 inner diameter H3 inner diameter H4 inner diameter Hll inner diameter T1 first distance T2 second . distance 5 P ? jap W1 outer diameter W2 outer diameter Y axial direction X radial direction 10

Claims

1. A scroll compressor comprising:an orbiting scroll;a frame retaining the orbiting scroll slidably;a fixed scroll forming a compression chamber together with the orbiting scroll;a middle shell storing the frame, the orbiting scroll, and the fixed scroll; andan upper shell sealing an upper side of the fixed scroll on the middle shell, whereinthe fixed scroll has a protrusion protruding outward in a radial direction between outer circumferential surfaces in an axial direction and having a first outer circumferential surface, and a second outer circumferential surface on a lower side in the axial direction relative to the protrusion,the upper shell has a first step portion where an inner diameter is increased on a lower side in the axial direction, at an inner circumferential surface on the middle shell side,the fixed scroll is fixed such that an upper end surface in the axial direction of the protrusion contacts with a first step surface of the first step portion of the upper shell and a lower end surface in the axial direction of the protrusion contacts with an upper end surface in theaxial direction of the middle shell,the second outer circumferential surface of the fixed scroll is formed in contact with a first inner circumferential surface on an upper side in the axial direction of the middle shell, anda first inner circumferential surface on a lower side in the axial direction of the first step portion of the upper shell is formed in contact with a first outer circumferential surface on an upper side in the axial direction of the middle shell.

2. The scroll compressor according to claim 1, wherein an outer diameter of the first outer circumferential surface of the fixed scroll is smaller than an inner diameter of the first inner circumferential surface of the upper shell.

3. The scroll compressor according to claim 1 or 2, whereinthe first inner circumferential surface of the upper shell has a recess recessed outward in the radial direction, only at a position opposed to the first outer circumferential surface of the fixed scroll, andthe lower end surface in the axial direction of the protrusion is fixed in contact with an entirety of the upperend surface in the axial direction of the middle shell.

4. The scroll compressor claims 1 to 3, whereinthe middle shell has <inner diameter is reduced, on a direction relative to the first of the middle shell, andthe frame is fixed in surface of the second step port the first inner circumferential

5. The scroll compressor claims 1 to 4, whereinthe middle shell has <inner diameter is reduced, on a direction relative to the firstof the middle shell, and a third diameter is reduced, at an inner between the fixed scroll and the in the axial direction relative andthe frame is fixed in ( surface of the second step port!according to any one ofsecond step portion where an lower side in the axialinner circumferential surfacecontact with a second step .on of the middle shell andsurface of the middle shell.according to any one ofsecond step portion where an lower side in the axialinner circumferential surface step portion where an inner circumferential surface frame and on an upper side .o the second step portion,ontact with a second step in of the middle shell and athird inner circumferential surface on an upper side in theaxial direction of the second step portion and a lower sidein the axial direction of the third step portion of themiddleshell.

6. The scroll compressor according to any one ofclaims 1 to 4, whereinthe second outer circumferential surface of the fixed scroll is formed continuously over a range of 360 degrees in a circumferential direction, andthe second outer circumferential surface of the fixed scroll and the first inner circumferential surface of the middle shell are fixed to each other by shrink fit.

7. The scroll compressor according to any one of claims 1 to 6, whereinan inner diameter of a second inner circumferential surface on an upper side in the axial direction of the first step portion of the upper shell is equal to an inner diameter of the first inner circumferential surface of the middle shell.

8. The scroll compressor according to any one ofclaims 1 to 7, whereinthe first outer circumferential surface of thefixed scroll has a first groove recessed in the radialdirection.

9. The scroll compressor according to any one ofclaims 1 to 8, whereina lower end surface in the axial direction of the fixed scroll has a second groove recessed upward in the axial direction, on an outer side in the radial direction relative to a scroll wrap of the scroll compressor.

10. The scroll compressor according to any one of claims 1 to 9, whereinthe middle shell has a fourth step portion where an outer diameter is increased, on a lower side in the axial direction relative to the first outer circumferential surface of the middle shell, anda lower end surface in the axial direction of the upper shell is located so as to be opposed to a fourth step surface of the fourth step portion of the middle shell with a gap therebetween.

11. The scroll compressor according to any one ofclaims 1 to 10, whereina welding portion is formed so that a lower end surface in the axial direction of the upper shell and the middle shell are welded and fixed at a position on a lowerside in the axial direction relative to the upper end surface of the middle shell.

12. The scroll compressor according to claim 11, whereinon the basis of rigidity of the frame and rigidity of the fixed scroll, a first distance from the upper end surface of the fixed scroll to the lower end surface of the upper shell, and a second distance from an upper end surface in the axial direction of the frame to the lower end surface of the upper shell, are determined, and thus a position of the welding portion is determined.

13. The scroll compressor according to claim 11 or 12, whereinthe upper shell has a tube portion which opens on the middle shell side, and a bottom portion connecting to the tube portion on a side opposite to the middle shell side in the axial direction, andthe upper shell has a heated mark due to heating, on an upper side in the axial direction of the tube portion.INTERNATIONAL SEARCH REPORT International application No. PCT / JP2023 / 029806 A. CLASSIFICATION OF SUBJECT MATTER F04C 18492(2006.01)1; F04C 29 / 00(2006.01)1 FI: F04C18 / 02 311B; F04C18 / 02 311Q; F04C29 / 00 B: F04C29 / 00 S According to International Patent Classification (IPC) or to both national classification ar id IPC B. FIELDS SEARCHEDMinimum documentation searched (classification system followed by classification symbols) F04C18 / 02; F04C29 / 00Documentation searched other than minimum documentation to the extent that such documents are included in the fields searchedPublished examined utility model applications of Japan 1922-1996Published unexamined utility model applications of Japan 1971-2023Registered utility model specifications of Japan 1996-2023Published registered utility model applications of Japan 1994-2023Electronic data base consulted during the international search (name of data base and, where practicable, search terms used)DOCUMENTS CONSIDERED TO BE RELEVANTCategory* Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim No. Y WO 2021 / 156938 Al (MITSUBISHI ELECTRIC CORP.) 12 August 2021 (2021-08-12) paragraphs [0009]-[0045], fig. 1-5 1-4,6-9, 11-13 A 5, 10 ___________ ____________________________________________________________________________ ___________________ Y JP 6-93982 A (TOSHIBA CORP.) 05 April 1994 (1994-04-05) paragraphs [0029]-[0041], fig. 1-2 1-4, 6-9, 11-13 A 5, 10 Y WO 2021 / 130875 Al (HITACHI-JOHNSON CONTROLS AIR CONDITIONING, INC.) 01 July 2021 (2021-07-01) paragraphs [0014]-[0060], fig. 1-10 8-9, 11-13 A 5, 10 Y WO 2018 / 179135 Al (MITSUBISHI ELECTRIC CORP.) 04 October 2018 (2018-10-04) paragraphs [0048]-[0051], fig. 8 9, 11-13 A 5, 10 A JP 11-22682 A (DAIKIN IND., LTD.) 26 January 1999 (1999-01-26) 1-13 entire text, all drawings| | Further documents are listed in the continuation of Box C. | J | See patent family annex.* Special categories of cited documents:“A” document defining the general state of the art which is not considered“T” later document published after the international filing date or priority“O”“P”to be of particular relevanceearlier application or patent but published on or after the international filing datedocument which may throw doubts on priority claim(s) or which is cited to establish the publication date of another citation or other special reason (as specified)document referring to an oral disclosure, use, exhibition or other meansdocument published prior to the international filing date but later than the priority date claimed‘Y’date and not in conflict with the application but cited to understand the principle or theory underlying the inventiondocument of particular relevance; the claimed invention cannot be considered novel or cannot be considered to involve an inventive step when the document is taken alonedocument of particular relevance; the claimed invention cannot be considered to involve an inventive step when the document is combined with one or more other such documents, such combination being obvious to a person skilled in the aitdocument member of the same patent familyDate of the actual completion of the international searchDate of mailing of the international search report03 October 2023Name and mailing address of the ISA / JPJapan Patent Office (ISA / JP)3-4-3 Kasumigaseki, Chiyoda-ku, Tokyo 100-8915JapanAuthorized officer17 October 2023Telephone No.INTERNATIONAL SEARCH REPORT Information on patent family membersInternational application No.PCT / JP2023 / 029806Patent document cited in search report Publication date (day / month / year) Patent family member)s) Publication date (day / month / year) WO 2021 / 156938 Al 12 August 2021 CN 115038871 A JP 6-93982 A 05 April 1994 (Family: none) WO 2021 / 130875 Al 01 July 2021 CN 114901948 A WO 2018 / 179135 Al 04 October 2018 US 2020 / 00327% Al paragraphs [0063]-[0066], fig. ____________________________________________________8________________________________________________ JP 11-22682 A 26 January 1999 US 6193485 Bl entire text, all drawings WO 1999 / 001664 Al EP 926344 Al CA 2264149 Al ES 2234122 T3 CN 1231022 A KR 2000-0068423 A MY 119357 A TW 366391 B

Images