Cylinder fitting structure and inverter

Abstract

A cylinder fitting structure in which a first cylinder having a first cylinder-shaped fitting portion that is a portion to be fitted with another cylinder and a second cylinder having a second cylinder-shaped fitting portion to be fitted with the first cylinder-shaped fitting portion are fitted and connected to each other, at least one of the first cylindrical fitting part and the second cylindrical fitting part is provided with a press-fit load release part, and the press-fit load release part deflects and deforms in the radial direction when the first cylindrical fitting part and the second cylindrical fitting part are fitted.

Description

Technical Field

[0001] The invention relates to a cylinder embedded structure and an inverter. Background Art

[0002] In power conversion devices, water pipes and frames are press-fitted between aluminum components. This requires a fitting structure that takes into account concerns about airtightness and process defects. For example, Patent Document 1 below discloses a cooling structure in which the fitting components are made of different materials, an adhesive is applied to the press-fit surfaces, and a press-fit fixture and anti-seizure fixture are used. This structure maintains compactness and weight while ensuring high reliability by implementing measures to prevent coolant leakage. Prior art literature Patent Literature

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2021-118616 Summary of the Invention Problems to be solved by the invention

[0004] In conventional structures, when press-fitting components made of the same material, although anaerobic adhesives are not used in the press-fit portions to ensure airtightness, the press-fitting of aluminum materials can lead to seizure and galling, resulting in concerns about airtightness and process defects. In view of this, the present invention aims to provide a cylindrical fitting structure and inverter that suppresses galling and reduces airtightness defects during press-fitting. Technical means to solve the problem

[0005] The cylindrical interlocking structure and inverter of the present invention are cylindrical interlocking structures in which the first cylindrical body and the second cylindrical body are interlocked and connected with each other, the first cylindrical body has a part that interlocks with the other cylindrical body, namely the first cylindrical interlocking part, and the second cylindrical body has a second cylindrical interlocking part that interlocks with the first cylindrical interlocking part. In this cylindrical interlocking structure, a press-in load release part is provided on at least one of the first cylindrical interlocking part or the second cylindrical interlocking part, and the press-in load release part is radially flexed and deformed when the first cylindrical interlocking part and the second cylindrical interlocking part are interlocked. Effects of the Invention

[0006] According to the present invention, it is possible to provide a cylindrical body fitting structure and an inverter that achieve the suppression of galling during press-fitting and the reduction of airtightness defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is an exploded view of the power conversion device. Figure 2 This is a diagram showing a process of fitting water pipes according to one embodiment of the present invention. Figure 3 This is a diagram showing a fitted state of water pipes according to one embodiment of the present invention. Figure 4 It is an explanatory diagram of a cylindrical body fitting structure according to one embodiment of the present invention. Figure 5 This is the first variant. Figure 6 This is the second variant. Figure 7 This is the third variant. Figure 8 This is the fourth variant. DETAILED DESCRIPTION

[0008] The following describes embodiments of the present invention with reference to the accompanying drawings. The following description and drawings are examples for illustrating the present invention and have been omitted or simplified as appropriate for clarity of description. The present invention may also be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

[0009] To facilitate understanding of the invention, the positions, sizes, shapes, and ranges of the components shown in the drawings may not necessarily represent their actual positions, sizes, shapes, and ranges. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, and ranges disclosed in the drawings.

[0010] (One embodiment and overall structure of the present invention) ( Figure 1 ) Power conversion device 1 includes a housing 2 and a lower cover 5. Housing 2 houses a power module 7 that includes switching semiconductor elements and performs power conversion. Lower cover 5 includes a water pipe 3. Water pipe 3 is press-fitted and connected to lower cover 5. Water pipe 3 and lower cover 5 are identical metal components formed by aluminum die-casting.

[0011] In the portion of the housing 2 that forms the cooling flow path between the housing 2 and the lower cover 5, sealing material 4 is applied to the groove at the connection between the housing 2 and the lower cover 5. The lower cover 5 is installed with the sealing material 4 sandwiched between them and secured with bolts, thereby sealing the cooling flow path formed between the housing 2 and the lower cover 5. This completely encloses the flow path of the water pipe 3 installed in the lower cover 5, forming a cooling flow path connecting the housing 2 and the water pipe 3. The refrigerant flowing within this path cools the entire power conversion device 1, including the power module 7.

[0012] Power module 7 is inserted into housing 2. Power module board 6 is mounted in housing 2 to hold inserted power module 7. Power conversion device 1 includes a flow path communicating with the cylindrical body and is housed in housing 2. A refrigerant for cooling power module 7 flows through the flow path formed in housing 2.

[0013] ( Figure 2 ) Figure 2 (a) is the internal structure diagram of the water pipe 3, Figure 2 (b) is a diagram showing a state where the water pipe 3 is fitted into the housing 2. Figure 2 (c) shows the state of the mating surface. Lubricating oil (not shown) is applied to the press-fit surface 11 of the water pipe 3 when it is mated with the housing 2 to prevent damage during press-fitting. The following description will refer to the mating portion of the housing 2 and the water pipe 3 as the first cylindrical body 15, and the water pipe 3 as the second cylindrical body 16.

[0014] The second cylinder 16 has a surface pressing portion 9 which is a plane perpendicular to the direction 10 in which the second cylinder 16 is pressed into the first cylinder 15. The surface pressing portion 9 is pressed by a press-in jig (not shown), so that the second cylinder 16 moves in the press-in direction 10 and fits into the first cylinder 15. In addition, by pressing the surface pressing portion 9, it is possible to suppress the press-in surface 11 of the second cylinder 16 from contacting one side of the first cylinder 15. In this way, since the press-in load can be evenly distributed, it is possible to prevent tilting during press-in engagement, and it helps to suppress the press-in surface 11 from being stuck and to prevent damage to the press-in surface 11.

[0015] A straight guide surface 12 is provided at the tip of the second cylindrical body 16. This provides the second cylindrical body 16 with a centering structure for aligning the centers of the respective holes of the second cylindrical body 16 and the first cylindrical body 15, which are mated at the start of the press-fitting process. Furthermore, the presence of the guide surface 12 aligns the centers of the cylindrical mating portions during press-fitting, suppressing unilateral contact of the press-fitting surfaces and evenly distributing the press-fitting load, thereby suppressing damage to the press-fitting surfaces and preventing galling.

[0016] like Figure 2 As shown in (b), as the second cylinder 16 contacts the first cylinder 15 and is gradually pressed in, the contact surface switches from the guide surface 12 to the pressing surface 11. In this way, when the first cylinder 15 is pressed into the second cylinder 16, the first part that contacts each other becomes the pressing start position 11a. That is, the pressing start position 11a is the intersection of the guide range and the pressing range. The pressing range refers to the range in which the axial diameter of the second cylinder 16 is larger than the hole diameter of the first cylinder 15. The top end of the second cylinder 16 partially expands the inner diameter of the first cylinder 15 as it is pressed into the first cylinder 15.

[0017] During press-fitting, the highest stress occurs at the point where the guide surface 12 switches to the press-fitting position, and this is where seizure begins. Seizure rarely occurs midway through press-fitting, but often occurs at the switching point. Therefore, the present invention reduces the likelihood of seizure by providing a portion that relieves the press-fitting load and temporarily increases the reduced diameter.

[0018] The second cylinder 16 is based on the fulcrum formed at the inner side (upper side on the paper) from the starting point 11a of the press-in, and the top end can bend and deform radially inward, which can alleviate the local stress of the starting point 11a of the press-in. The deflection mentioned here refers to the large dimensional change caused by the reduction or expansion of the diameter of the second cylinder 16 in order to achieve a balanced relationship between the second cylinder 16 and the expansion of the first cylinder 15 during the press-in. The details of the parts related to this deflection will be described later.

[0019] ( Figure 3 ) The first cylindrical body 15 includes a first cylindrical interlocking portion 15a, which is a portion that interlocks with the second cylindrical body 16 (or other cylindrical body). Furthermore, the second cylindrical body 16 includes a second cylindrical interlocking portion 16a that interlocks with the first cylindrical interlocking portion 15a. As described above, by pressing the second cylindrical interlocking portion 16a into the first cylindrical interlocking portion 15a, the second cylindrical body 16 is connected to the flow path 18. This interlocking structure of the cylindrical bodies allows the refrigerant to circulate throughout the entire power conversion device 1.

[0020] ( Figure 4 ) In this fitting structure, the second cylindrical fitting portion 16a is provided with a press-fit load relief portion 19 that is radially flexed and deformed when the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are fitted together.

[0021] In the portion where the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a interlock, a press-in load relief portion 19 is provided at the opposing end of the first cylindrical fitting portion 15a or the end of the second cylindrical fitting portion 16a. Furthermore, as described above, the press-in load relief portion 19 includes a press-in start portion 11a, which first presses into contact with the surfaces where the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a interlock. When the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a interlock, the press-in start portion 11a first contacts the minimum inner diameter portion of the inner circumference of the first cylindrical fitting portion 15a on the outer periphery of the first thinned portion 14, described later, during press-in contact.

[0022] In addition, the press-in load release portion 19 has a flexure fulcrum portion 13, which serves as a fulcrum for radially flexing the first or second cylindrical fitting portion 15a, 16a when the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are engaged. This flexure fulcrum portion 13 is determined by providing a first thinning portion 14, which will be described later. The flexure fulcrum portion 13 is located closer to the side opposite to the press-in direction than the press-in starting portion 11a in the second cylindrical body 16. This allows deformation of the first and second cylindrical fitting portions 15a, 16a during press-in engagement, and by radially inwardly flexing the end of the second cylindrical fitting portion 16a, a stress relief effect can be achieved during engagement. Furthermore, management during the mass production process becomes easier, and this also helps improve the yield rate problem caused by poor press-in.

[0023] In the portion where the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a fit together, the press-in load release portion 19 has a first thinning portion 14 on the side of the second cylindrical fitting portion 16a. The overall wall thickness of the waterway pipe 3 including the second cylindrical body 16 becomes the wall thickness required by die casting, but the first thinning portion 14 near the top of the press-in portion is formed to be thinner than the standard wall thickness. With such a structure, no damage will be caused on the press-in surface, which can help to stabilize and ensure the airtightness performance and improve the yield rate. In addition, after the press-in is completed, since the press-in length after the press-in is equal, the airtightness does not change, which helps to improve reliability.

[0024] As described above, the first cylinder 15 and the second cylinder 16 are formed of the same material. As a result, the components are not subject to the difference in linear expansion when affected by heat, and the state of the press-fit surface can be kept fixed when connected to each other, thereby improving reliability. In addition, by making the first cylinder 15 and the second cylinder 162 of the same material, there will be no deviation of the press-fit surface due to temperature changes, so there is no impact on airtightness. In addition, there is no need for anaerobic adhesives, which, if used on the press-fit surface, have the risk of poor airtightness due to deterioration over time, and high durability can be obtained. In addition, it can also contribute to responding to customers who do not like to use adhesives in the waterway part.

[0025] The flexure support 13 is formed at the rounded end of the first thinned portion 14. The thinned area of ​​the first thinned portion 14 is not limited; it is formed so that the pressure load is calculated based on the required airtightness and the component flexes accordingly. This can alleviate the local stress at the start of the press-fit, preventing surface damage or curling.

[0026] The first thinned portion 14 has the aforementioned guide surface 12 on its outer circumferential surface, on the pressing side closer to the second cylindrical body 16 than the pressing start point 11a. The guide surface 12 is a cylindrical surface parallel to the pressing direction of the second cylindrical body 16. Since the guide surface 12 at the tip of the second cylindrical body 16 is straight, the length of the guide, the surface that first contacts during pressing, can be increased, thereby improving the centering accuracy during pressing.

[0027] (First Modification) ( Figure 5 ) The end portion of the second cylindrical body 16 has at least three notches 21 arranged at equal intervals in the circumferential direction of the end portion, which are notched from the insertion tip portion of the second cylindrical fitting portion 16a toward the side opposite to the insertion direction, and at least three peripheral walls 22 adjacent to each other in the circumferential direction between the notches 21, serving as the press-fit load relief portion 19. Due to the cross-sectional view of the accompanying drawings, the notches 21 and peripheral walls 22 are shown separately.

[0028] When the first and second cylindrical fitting portions 15a and 16a are press-fitted into contact, the press-fitting start portion 11a on the outer periphery of the cutout portion 21 first contacts the smallest inner diameter portion of the inner periphery of the first cylindrical fitting portion 15a.

[0029] On the inner periphery of the cutout portion 21, the flexure support portion 13 is formed closer to the side opposite to the press-in side of the second cylindrical body 16 than the press-in start portion 11a, and supports the radially inward flexural deformation of the second cylindrical body 16 when the first cylindrical fitting portion 15a contacts the second cylindrical fitting portion 16a.

[0030] In order to bend the second cylindrical body 16, the notch apex 21b (bending fulcrum 13) needs to be located further back than the push-in start point 11a in the push-in direction.

[0031] Therefore, with Figure 4 Similar to the embodiment described in , when the second cylinder 16 is pressed into the first cylinder 15, the cutout portion 21 is reduced in diameter toward the inner diameter side, thereby alleviating stress concentration. In addition, since the surface pressure after pressing remains substantially unchanged, there is an advantage in that the airtightness is not affected. In addition, by providing three or more cutout portions 21, compared with a case where the number of cutout portions is two or less, it is less likely that an offset will occur in the circumferential deformation, and the peripheral wall portion 22 deforms uniformly as a whole. In addition, by providing the cutout portion 21, there is an advantage in that the thickness of the guide surface 12 no longer needs to be thinned.

[0032] (Second Modification) ( Figure 6 ) In the portion where the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are fitted, a second thinned portion 20 is provided on the first cylindrical fitting portion side as a press-fit load release portion 19. When the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are press-fitted into contact, the press-fit start portion 11a on the inner circumference of the second thinned portion 20 first contacts the maximum outer diameter portion of the outer circumferential surface of the second cylindrical fitting portion 16a.

[0033] On the outer periphery of the second thinned portion 20, a flexure support portion 13 is formed on the side opposite to the pressing side of the second cylindrical body 16 that is closer to the pressing start portion 11a, and supports the flexural deformation of the first cylindrical body 15 toward the radial outside when the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are in contact.

[0034] Thus, a groove is formed radially outward at the end portion of the first cylindrical body 15, providing a second thinned portion 20 as the press-in load relief portion 19. The groove is set slightly deeper than the press-in start point 11a, thereby positioning the flexure support 13 closer to the press-in direction than the press-in start point 11a. As a result, the first cylindrical body 15 expands in diameter during press-in, alleviating stress concentration. Furthermore, the surface pressure after press-in remains virtually unchanged, thereby preventing any impact on airtightness.

[0035] (Third Modification) ( Figure 7 ) In the portion where the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are fitted, a first thinned portion 14 is provided on the outer peripheral side of the second cylindrical fitting portion 16a as a press-fit load release portion 19. When the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are pressed into contact, the press-fit start portion 11a on the inner peripheral portion of the first thinned portion 14 first contacts the maximum outer diameter portion of the outer peripheral surface of the first cylindrical fitting portion 15a.

[0036] A flexure support 13 is formed on the outer periphery of the first thinned portion 14, closer to the side opposite to the press-in starting portion 11a, toward the second cylindrical body 16, and supports radially outward flexure of the second cylindrical body 16 when the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a come into contact. Thus, in a configuration in which the outer shape of the first cylindrical body 15 fits into the inner diameter of the second cylindrical body 16, a constant flow path cross-sectional area can be ensured, and stress during press-in can be alleviated.

[0037] (Fourth Modification) ( Figure 8 ) In the area where the first and second cylindrical fitting portions 15a, 16a intersect, a second reduced portion 20 is provided on the first cylindrical fitting portion 15a side as a press-fit load relief portion 19. When the first and second cylindrical fitting portions 15a, 16a are press-fitted into contact, the press-fit start point 11a on the outer periphery of the second reduced portion 20 first contacts the minimum inner diameter portion of the inner circumferential surface of the second cylindrical fitting portion 16a. A flexure support point 13 is formed on the inner periphery of the second reduced portion 20, closer to the press-fit side of the second cylindrical body 16 than the press-fit start point 11a. This supports radially inward flexural deformation of the first cylindrical body 15 when the first and second cylindrical fitting portions 15a, 16a come into contact.

[0038] Therefore, in the case of a structure in which the outer shape of the first cylinder 15 is fitted with the inner diameter side of the second cylinder 16, Figure 7 Likewise, a constant flow path cross-sectional area can be ensured, and stress during press-fitting can be alleviated.

[0039] The above description describes the configuration of the present invention, but the flexure fulcrum 13 may also be located on both the first cylindrical body 15 and the second cylindrical body 16. By combining these two configurations and providing the press-in load release portion 19 on both the first cylindrical body 15 and the second cylindrical body 16, not only can the local stress during press-in be released by flexure, but also deformation can be achieved with a smaller load, further enhancing the effects described above.

[0040] According to one embodiment of the present invention described above, the following effects are achieved.

[0041] (1) The cylindrical interlocking structure of the present invention is a cylindrical interlocking structure in which a first cylindrical body 15 and a second cylindrical body 16 are interlocked and connected with each other. The first cylindrical body 15 has a first cylindrical interlocking portion 15a that is interlocked with the other cylindrical body, and the second cylindrical body 16 has a second cylindrical interlocking portion 16a that is interlocked with the first cylindrical interlocking portion 15a. A press-in load release portion 19 is provided on at least one of the first cylindrical interlocking portion 15a and the second cylindrical interlocking portion 16a. The press-in load release portion 19 is radially flexed and deformed when the first cylindrical interlocking portion 15a and the second cylindrical interlocking portion 16a are interlocked. Thus, a cylindrical interlocking structure that suppresses seizure during press-in interlocking and reduces poor airtightness can be provided.

[0042] (2) The press-fit load relief portion 19 includes a thinned portion 14, 20 on at least one of the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a. These thinned portions 14, 20 are capable of radially flexing and deforming when the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are fitted. The thinned portions 14, 20 include a flexure support portion 13 that serves as a fulcrum for radial flexure and deformation. This allows the press-fit load to be evenly distributed, thereby preventing tilting during press-fit engagement.

[0043] (3) The press-in load release portion 19 has a press-in start portion 11a, which is located at the end of the first cylindrical fitting portion 15a or the end of the second cylindrical fitting portion 16a, which is opposite to each other, at the portion where the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are fitted. The first press-in contact occurs on the surfaces where the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are fitted. The flexure support portion 13 is located on the press-in direction 10 side relative to the press-in start portion 11a in the first cylindrical body 15 and on the side opposite to the press-in direction 10 side relative to the press-in start portion 11a in the second cylindrical body 16. When the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are fitted, the first cylindrical fitting portion 15a is flexed and deformed radially outward at the end thereof and radially inward at the end thereof. This helps suppress galling of the press-fit surface 11 and prevent damage to the press-fit surface 11 .

[0044] (4) The press-in load release portion 19 has a first thinned portion 14 on the side of the second cylindrical fitting portion 16a at the portion where the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are fitted. When the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are pressed into contact, the press-in start portion 11a on the outer periphery of the first thinned portion 14 first contacts the minimum inner diameter portion of the inner periphery of the first cylindrical fitting portion 15a. On the inner periphery of the first thinned portion 14, a flexure support portion 13 is formed on the side opposite to the press-in side of the second cylindrical body 16 that is closer to the press-in start portion 11a, and supports the radially inward flexural deformation of the second cylindrical body 16 when the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are in contact. As a result, the second cylindrical body 16, mainly on the press-in side, obtains a stress relief effect during fitting.

[0045] (5) The end portion of the second cylindrical body 16 has: at least three cutout portions 21, which are cut out from the insertion tip portion of the second cylindrical fitting portion 16a to the side opposite to the insertion direction and are arranged at equal intervals in the circumferential direction of the end portion; and at least three peripheral wall portions 22, which are adjacent to each other in the circumferential direction of the cutout portions 21. When the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are pressed into contact, the pressing start portion 11a on the outer periphery of the cutout portion 21 first contacts the minimum inner diameter portion of the inner peripheral surface of the first cylindrical fitting portion 15a. In the inner periphery of the cutout portion 21, the flexure support portion 13 is formed closer to the side opposite to the pressing side of the second cylindrical body 16 than the pressing start portion 11a, and supports the flexural deformation of the second cylindrical body 16 in the radial direction inward when the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are in contact. Therefore, even if the end portion of the second cylindrical body 16 on the press-fit side is in another shape, the effect of alleviating stress during fitting can be obtained.

[0046] (6) The press-in load release portion 19 has a second thinning portion 20 on the side of the first cylindrical fitting portion 15a at the portion where the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are fitted. When the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are pressed into contact, the press-in start portion 11a on the inner periphery of the second thinning portion 20 first contacts the maximum outer diameter portion of the outer periphery of the second cylindrical fitting portion 16a. On the outer periphery of the second thinning portion 20, a flexure support portion 13 is formed on the side opposite to the press-in side of the second cylindrical body 16 that is closer to the press-in start portion 11a, and supports the radially outward flexural deformation of the first cylindrical body 15 when the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are in contact. As a result, the first cylindrical body 15, which is mainly on the press-in side, obtains a stress relief effect during fitting.

[0047] (7) The press-in load release portion 19 has a first thinned portion 14 on the side of the second cylindrical fitting portion 16a at the portion where the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are fitted. When the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are pressed into contact, the press-in start portion 11a on the inner periphery of the first thinned portion 14 first contacts the maximum outer diameter portion of the outer periphery of the first cylindrical fitting portion 15a. A flexure support portion 13 is formed on the outer periphery of the first thinned portion 14 on the side opposite to the press-in side of the second cylindrical body 16, closer to the press-in start portion 11a, and supports the radially outward flexural deformation of the second cylindrical body 16 when the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are in contact. Thus, even when the second cylindrical body 16 is fitted into the convex cylindrical body of the first cylindrical body 15 , the second cylindrical body 16 on the main press-fit side can obtain a stress relaxation effect during fitting.

[0048] (8) The press-in load relief portion 19 has a second thinned portion 20 on the first cylindrical fitting portion 15a side at the portion where the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are fitted. When the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are press-fitted into contact, the press-in start portion 11a on the outer periphery of the second thinned portion 20 first contacts the minimum inner diameter portion of the inner periphery of the second cylindrical fitting portion 16a. A flexure support portion 13 is formed on the inner periphery of the second thinned portion 20 on the press-in side closer to the second cylindrical body 16 than the press-in start portion 11a. The flexure support portion 13 supports the radially inward flexural deformation of the first cylindrical body 15 when the first cylindrical fitting portion 15a and the second cylindrical fitting portion 16a are in contact. Thus, even when the second tube 16 is fitted into the convex tube of the first tube 15 , the first tube 15 on the side that is mainly pressed in can obtain a stress relaxation effect during fitting.

[0049] (9) The first thinned portion 14 has a guide surface 12 on the outer peripheral surface, on the pressing side closer to the second cylinder 16 than the pressing start point 11a, and the guide surface 12 has a cylindrical surface parallel to the pressing direction of the second cylinder 16. This improves the centering accuracy during pressing.

[0050] (10) The first cylindrical body 15 and the second cylindrical body 16 are made of the same material, thereby improving the reliability during connection.

[0051] (11) The second cylindrical body 16 has the surface pressing portion 9 which is a flat surface perpendicular to the press-in direction of the second cylindrical body 16. This can suppress one-sided contact during press-in.

[0052] (12) The power conversion device 1 includes: a housing 2 having a flow path 18 communicating with a first cylindrical body 15 and a second cylindrical body 16; and a power module 7 housed in the housing 2, having a switching semiconductor element and performing power conversion. A refrigerant for cooling the power module 7 flows within the flow path 18. Thus, a power conversion device 1 having a cylindrical body fitting structure that suppresses galling and reduces airtightness during press-fitting can be provided.

[0053] In addition, the present invention is not limited to the above-mentioned embodiment, and various modifications or other configurations can be combined within the scope of the present invention. In addition, the present invention is not limited to the structure having all the configurations described in the above-mentioned embodiment, and also includes a structure in which part of the configuration is deleted. Explanation of symbols

[0054] 1 Power conversion device 2 shell 3 Water pipes 4 Sealing materials 5 Lower cover 6 Power module board 7 Power Module 9-sided pressing part 10 Pressing direction 11 Pressing surface 11a Press into the starting position 12 guide surface 13flexion fulcrum part 141st thinning section 15 1st cylinder 15a 1st cylindrical fitting part 16 Second cylinder 16a 2nd cylindrical fitting part 18 flow paths 19 Press-in load release part 20 2nd thinning section 21 incision 21b incision apex 22 surrounding wall 23 cylindrical surface.

Claims

1. A cylindrical body interlocking structure, wherein a first cylindrical body and a second cylindrical body are interlocked and connected with each other, wherein the first cylindrical body has a first cylindrical interlocking portion that interlocks with the other cylindrical body, and the second cylindrical body has a second cylindrical interlocking portion that interlocks with the first cylindrical interlocking portion. The cylindrical body interlocking structure is characterized in that: A press-fit load relief portion is provided on at least one of the first cylindrical fitting portion or the second cylindrical fitting portion. The press-fit load relief portion is deformed in a radial direction when the first cylindrical fitting portion and the second cylindrical fitting portion are fitted together.

2. The cylindrical body interlocking structure according to claim 1, characterized in that: The press-fit load release portion has a thinned portion on at least one of the first cylindrical fitting portion or the second cylindrical fitting portion, and the thinned portion can be bent and deformed in the radial direction when the first cylindrical fitting portion and the second cylindrical fitting portion are fitted together. The thinned portion includes a bending support point portion serving as a support point for bending and deformation in the radial direction.

3. The cylindrical body interlocking structure according to claim 2, characterized in that: The press-in load release portion has a press-in start portion, which is provided at a portion where the first tubular fitting portion and the second tubular fitting portion are fitted, at an end portion of the first tubular fitting portion or an end portion of the second tubular fitting portion facing each other, and is first pressed into contact with each other on the surfaces where the first tubular fitting portion and the second tubular fitting portion are fitted and contacted. The flexure fulcrum is located in the first cylindrical body on the side closer to the pressing direction than the pressing start position, and in the second cylindrical body on the side opposite to the pressing direction than the pressing start position, and when the first cylindrical fitting portion and the second cylindrical fitting portion are fitted together, the end portion of the first cylindrical fitting portion is flexed and deformed radially outward, and the end portion of the second cylindrical fitting portion is flexed and deformed radially inward.

4. The cylindrical body interlocking structure according to claim 3, characterized in that: The press-fit load release portion has a first thinned portion on the second cylindrical fitting portion side at a portion where the first cylindrical fitting portion and the second cylindrical fitting portion fit together. When the first cylindrical fitting portion and the second cylindrical fitting portion are pressed into contact, the press-in starting point first contacts the minimum inner diameter portion of the inner peripheral surface of the first cylindrical fitting portion at the outer peripheral portion of the first thinned portion. On the inner periphery of the first thinned portion, the flexure fulcrum is formed on the side opposite to the pressing side of the second cylindrical body that is closer to the pressing start portion, and supports the radially inward flexural deformation of the second cylindrical body when the first cylindrical fitting portion and the second cylindrical fitting portion are in contact.

5. The cylindrical body interlocking structure according to claim 3, characterized in that: The end portion of the second cylindrical body has: at least three cutout portions, which are cut out from the insertion tip portion of the second cylindrical fitting portion toward the side opposite to the insertion direction and are arranged at equal intervals in the circumferential direction of the end portion; and at least three peripheral wall portions, which are adjacent to each other along the circumferential direction between the cutout portions. When the first cylindrical fitting portion and the second cylindrical fitting portion are pressed into contact, the press-in starting point at the outer periphery of the cutout portion first contacts the minimum inner diameter portion of the inner periphery of the first cylindrical fitting portion. The flexure support portion is formed on the inner periphery of the cutout portion at a side opposite to the press-in side of the second cylindrical body that is closer to the press-in start portion, and supports the radially inward flexural deformation of the second cylindrical body when the first cylindrical fitting portion and the second cylindrical fitting portion are in contact.

6. The cylindrical body interlocking structure according to claim 3, characterized in that: The press-fit load release portion has a second thinned portion on the first cylindrical fitting portion side at a portion where the first cylindrical fitting portion and the second cylindrical fitting portion are fitted together. When the first cylindrical fitting portion and the second cylindrical fitting portion are pressed into contact, the press-in starting point first contacts the maximum outer diameter portion of the outer peripheral surface of the second cylindrical fitting portion at the inner peripheral portion of the second thinned portion. On the outer periphery of the second thinned portion, the flexure fulcrum is formed closer to the side opposite to the pressing side of the second cylindrical body than the pressing start portion, and supports the flexural deformation of the first cylindrical body toward the radial outside when the first cylindrical fitting portion and the second cylindrical fitting portion are in contact.

7. The cylindrical body interlocking structure according to claim 3, characterized in that: The press-fit load release portion has a first thinned portion on the second cylindrical fitting portion side at a portion where the first cylindrical fitting portion and the second cylindrical fitting portion fit together. When the first cylindrical fitting portion and the second cylindrical fitting portion are pressed into contact, the press-in starting point first contacts the maximum outer diameter portion of the outer peripheral surface of the first cylindrical fitting portion at the inner peripheral portion of the first thinned portion. The flexure support portion is formed on the outer periphery of the first thinned portion at a side opposite to the press-in side of the second cylindrical body that is closer to the press-in start portion, and supports the radially outward flexural deformation of the second cylindrical body when the first cylindrical fitting portion and the second cylindrical fitting portion are in contact.

8. The cylindrical body interlocking structure according to claim 3, characterized in that: The press-fit load release portion has a second thinned portion on the first cylindrical fitting portion side at a portion where the first cylindrical fitting portion and the second cylindrical fitting portion are fitted together. When the first cylindrical fitting portion and the second cylindrical fitting portion are pressed into contact, the press-in starting point first contacts the minimum inner diameter portion of the inner peripheral surface of the second cylindrical fitting portion at the outer peripheral portion of the second thinned portion. The flexure support portion is formed on the inner periphery of the second thinned portion at the press-in side of the second cylindrical body relative to the press-in start portion, and supports the radially inward flexural deformation of the first cylindrical body when the first cylindrical fitting portion and the second cylindrical fitting portion contact each other.

9. The cylindrical body interlocking structure according to claim 4, characterized in that: The first thinned portion has a guide surface on the outer peripheral surface at the pressing side closer to the second cylindrical body than the pressing start position. The guide surface has a cylindrical surface parallel to the press-fitting direction of the second cylindrical body.

10. The cylindrical body interlocking structure according to claim 1, characterized in that: The first cylinder and the second cylinder are made of the same material.

11. The cylindrical body interlocking structure according to claim 10, characterized in that: The second cylindrical body includes a surface pressing portion which is a flat surface perpendicular to the pressing direction of the second cylindrical body.

12. An inverter, characterized in that: have: The cylindrical interlocking structure according to any one of claims 1 to 11; a frame having a flow path communicating with the first cylinder and the second cylinder; and The power module is housed in the housing and has a switching semiconductor element and performs power conversion. A refrigerant for cooling the power module flows inside the flow path.

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