ELECTRIC COMPRESSOR

Abstract

An electric compressor (1) to be mounted on a vehicle, the electric compressor (1) comprising: a housing (13) for mounting on the vehicle, wherein the housing (13) accommodates a device main body (10) comprising a compression mechanism (11) for compressing a coolant and a motor (12) for outputting a torque to actuate the compression mechanism (11), wherein the housing (13) has a cylindrical part (15) that surrounds the main body of the device (10), wherein a projection (20;22;24-26) which projects outwards in a radial direction (D1) of the cylindrical part (15) is arranged on the cylindrical part (15), wherein a wall thickness (t) of the cylindrical part (15) is increased at the position of the projection (20;22;24-26), and wherein a cross-section of the projection (20;22;24-26) has an arc-like shape orthogonal to an axial line (15L) of the cylindrical part (15) projecting outwards in the radial direction (D1), such that the stiffness in the plate thickness direction gradually changes in the circumferential direction to end edges in regions (203) from the width-direction center of the projection to end edges, wherein the end edges (202) refer to positions in the circumferential direction at which a circular arc (20C), which is the basic shape that determines the outer shape of the projection (20;22;24-26), intersects a circle (15C) which is the basic shape of an outer circumferential surface (15A) of the cylindrical part (15); wherein the projection (20) has a support element (205) configured to support a buffer element (4) on the housing (13) which is arranged between the electric compressor (1) to be mounted on the vehicle and an element (9) of the vehicle (1); wherein the support part (205) does not extend beyond the projection (20) in the circumferential direction of the housing (13).

Description

[0001] The present invention relates to an electric compressor having a housing to be mounted on a vehicle.

[0002] For example, a vehicle is mounted with a device embedded in a motor, such as an electric compressor for forming an air conditioner. The electric compressor includes the motor, a compression mechanism actuated by torque output from the motor, and a drive circuit unit for driving the motor. The motor and the compression mechanism are housed in a cylindrical casing, and the casing is integrated with the drive circuit unit (e.g., JP 5 505 352 B).

[0003] In JP 5 505 352 B, a part of a housing of the drive circuit unit is made thick in order to protect the drive circuit from impacts.

[0004] From DE 60 2006 000 208 T2, an electric compressor is known in which a cylindrical part of a housing is provided with thickened portions projecting outwards in the radial direction, distributed around the circumference and each extending in the direction of the axial line. These thickened portions on the housing have a cross-sectional shape in a sectional plane perpendicular to the axial line which, although also symmetrical in the circumferential direction, have a constant wall thickness over essentially the entire extent of the projection in the circumferential direction. The outer circumference of the projections therefore approximates the shape of a larger circle concentric with the "normal" outer circumference of the cylindrical part. In the area of ​​the ends, the wall thickness then drops abruptly and regressively, so that a sharp edge is formed at the ends.

[0005] DE 10 2009 045 966 ​​A1 discloses an electric compressor in which a cylindrical part of a housing has at least one radially outwardly projecting projection on the outer circumference, which extends in the direction of the axial line and has a crescent-shaped outer contour. This projection or its function is not further described in DE 10 2009 045 966 ​​A1.

[0006] Further prior art is shown in JP 2013-068187 A, DE 33 44 271 A1 and in CN 2 935 603 Y.

[0007] Assuming that a vehicle collides with an external object while driving, there is a possibility that an element 9 of the vehicle collides with the side surface of a housing 8 of an electric compressor ( Fig. 13A). In such a case, as illustrated by the distribution of the stress acting on the housing 8 in Fig. 13B, a large tensile stress is generated at a portion 85P on the rear side (inner periphery of the casing) of a part of the casing 8 with which the member 9 of the vehicle collided. Once excessive deformation or damage to the casing 8 caused by the stress creates a gap between the casing 8 and a drive circuit unit (not shown), this may result in electrical leakage of the drive circuit unit. Therefore, it is necessary to ensure the strength of the casing 8. However, due to limitations in installation space, weight restrictions, etc., it is difficult to provide the casing 8 with a sufficient plate thickness to ensure strength.

[0008] In view of the foregoing, it is an object of the present invention to provide a housing structure for an electric compressor to be mounted on a vehicle to improve the strength against a collision.

[0009] An electric compressor to be mounted on a vehicle according to the present invention has the features of claim 1, 5 or 7. The dependent claims relate to further advantageous aspects of the invention.

[0010] Stress acting on the cylindrical part at the time of a vehicle collision can be dispersed by providing a protruding portion on the cylindrical part of the housing, such as an arc-like protrusion or a protruding portion with an outline along a tangential line drawn to a virtual arc and the cylindrical part of the housing, or a hemispherical protruding portion, or the like. This prevents stress from being concentrated locally on the cylindrical part and reduces the overall stress.

[0011] The shape of the protruding portion according to the present invention causes an increase in plate thickness only in the portion of the cylindrical part where the protruding portion is provided, while the stress distribution makes it possible to achieve effects similar to the case where the plate thickness is increased over the entire circumference of the cylindrical part. Therefore, the strength of the housing against a vehicle collision is ensured without increasing the weight of the device to be mounted on the vehicle. Fig. 1A is a side view of an electric compressor to be mounted on a vehicle according to a first embodiment of the present invention. Fig. 1B is a perspective view of a cylindrical part of a housing of the electric compressor. Fig. Fig. 2 illustrates a cross section of an arc-like protruding portion formed on the cylindrical part of the housing (a cross section taken along the line II-II in Fig. 1A). Fig. 3A is a schematic view illustrating a state in which a collision of a vehicle during running causes a member of the vehicle to collide with the cylindrical part of the housing. Fig. 3B and Fig. 3C are each a schematic view illustrating a cylindrical part on which a protruding portion not having an arc-like shape has been formed. Fig. 4 illustrates the relationship between "B", which is a dimension (width) measured from a tip end of the protruding portion to a position of an end edge of the protruding portion in a tangential direction drawn to the tip end, "A", which is a protrusion amount of the protruding portion to the tip end, and stress ratios, where (1) indicates a case where no protruding portion is provided. Fig. 5 is a graph illustrating the relationship between the protrusion amount “A” and the width “B” of the protruding portion when the stress ratios are the smallest. Fig. 6A to 6C illustrate substantially arcuate protruding portions similar to an arc. Fig. 7 is a perspective view of a cylindrical part of a casing of the electric compressor to which a buffer member has been provided. Fig. 8A and Fig. 8B illustrate the housing of the electric compressor to be mounted on a vehicle in a second embodiment, wherein Fig. 8A illustrates an area which is 1 / 4 of the cylindrical part of the housing, and Fig. 8B is an enlarged view of the protruding portion. Fig. Fig. 9 illustrates the relationship between the radius of curvature of an R part at the base of the protruding portion and stress ratios, where 1 is a case where no protruding portion is provided. Fig. 10 illustrates the cylindrical part of the housing of an electric compressor to be mounted on a vehicle in a third embodiment. Fig. 11 illustrates the cylindrical part of the housing of an electric compressor to be mounted on a vehicle according to a variation of the present invention. Fig. 12A to 12C illustrate the cylindrical part of the housing of a compressor housing of the fourth embodiment. Fig. Figure 12B is a cross-sectional view taken along line bb in Figure 12A and Fig. 12C is a cross-sectional view along the line cc in Fig. 12A. Fig. Figure 13A illustrates a cylindrical portion of a conventional compressor housing. Fig. Figure 13B illustrates the stress distribution when an element of a vehicle collided with the cylindrical part of the housing.

[0012] The embodiments of the present invention will be described below by referring to the accompanying drawings.

[0013] One in Fig. 1A illustrated compressor 1 (electric compressor) is mounted on a vehicle such as an automobile and forms an air conditioning system for the vehicle.

[0014] The compressor 1 includes: a device main body 10 having a compression mechanism 11 for compressing a refrigerant and a motor 12 for outputting torque to actuate the compression mechanism 11; a housing 13 for accommodating the device main body 10; and a drive circuit unit 14 for driving the motor 12. The drive circuit unit 14 is integrated into the housing 13.

[0015] The compressor 1 is supported by a support member (not shown) of an engine mounted on the vehicle.

[0016] The housing 13 includes a cylindrical portion 15 surrounding the device main body 10 and a cover 16 provided at one end portion of the cylindrical portion 15. The other end of the cylindrical portion 15 is provided with a circuit housing 140 of the drive circuit unit 14.

[0017] The cylindrical part 15 and the cover 16 are provided with fastening sections 18 which are fixed to a support member such as a motor.

[0018] The drive circuit unit 14 includes a circuit board 142 on which circuit elements 141 are mounted, and the circuit case 140 for accommodating the circuit board 142.

[0019] The drive circuit unit 14 may be provided on the side surface portion of the cylindrical part 15.

[0020] Once the vehicle experiences a collision while traveling, the vehicle's structural body (such as a frame) may collide with the cylindrical part 15 from the side. Assuming that a load of up to tens of tons in such a situation causes excessive deformation of the casing 13 and thus a gap between the cylindrical part 15 and the circuit casing 140, connectors or the like connected to high-voltage circuit components embedded in the drive circuit unit 14 are exposed to the outside, which is undesirable.

[0021] Therefore, it is considered to provide the cylindrical part 15 with a plate thickness sufficient to ensure impact strength. However, it would be necessary to ensure that the interior of the cylindrical part 15 has the volume required for the capacities required by the compressor 1, and there are also upper limits on the outer diameter of the compressor 1 due to limitations of the space in which the compressor 1 is to be installed. Thus, it would be difficult to increase the plate thickness over the entire circumference of the cylindrical part 15. Increasing the plate thickness is also difficult due to the requirement for a reduced weight of the compressor 1.

[0022] Therefore, in the present embodiment, a protruding portion 20 is formed on the cylindrical part 15 as described below, so that the strength of the housing 13 against collision and the like is ensured.

[0023] As in Fig. 1B and in Fig. 2, the protruding portion 20, which protrudes outward in a radial direction D1 of the cylindrical part 15, is provided on the cylindrical part 15. The protruding portion 20 may be arranged at least at a region in the circumferential direction of the cylindrical part 15.

[0024] The protruding portion 20 may protrude in the same direction in which the vehicle travels forward. More specifically, the protruding portion 20 is arranged in or near a horizontal plane having an axial line 15L of the cylindrical part 15.

[0025] The cylindrical part 15, which has the protruding portion 20, is integrally formed by casting or die-casting with a metallic material such as an aluminum alloy. The cylindrical part 15 is formed with a prescribed plate thickness t (wall thickness).

[0026] As in Fig. As illustrated in Figure 2, the protruding portion 20 has an arcuate cross-section that protrudes outward in the radial direction D1. The cross-section is orthogonal to the axial line 15L of the cylindrical part 15. The external shape of the protruding portion 20 is determined based on a single arc 20C and is formed with line symmetry around the center line (long dashed, double short dashed lines) in the width direction.

[0027] The protruding portion 20 extends approximately over the entire length along the axial line 15L ( Fig. 1B) of the cylindrical part 15. The same cross-section of the protruding portion 20 is continued over the entire length direction (the direction orthogonal to the blade surface Fig. 2) of the protruding section 20 (projection).

[0028] As in Fig. As shown in Figure 3, the arcuate protruding portion 20 of the cylindrical part 15 can absorb the load exerted by the vehicle element 9 located near the cylindrical part 15 during a vehicle collision. The presence of the protruding portion 20 allows for a reduction in the tensile stress acting on the inner peripheral surface 15B located on the rear side of the protruding portion 20.

[0029] This will be described by comparing a case where the protruding portion 20 is not arranged on the cylindrical part (13B) with a case where protruding portions 30 and 31, each having a non-arc shape, are arranged on the cylindrical part ( Fig. 3B and Fig. 3C).

[0030] As shown in Fig. 13B, in the case where the protruding portion 20 is not provided, the plate thickness t of a cylindrical part 85 is uniform. Therefore, the rigidity of the cylindrical part 85 in the plate thickness direction (radial direction) is uniform in the circumferential direction.

[0031] Assuming that the member 9 of the vehicle collides with this cylindrical part 85, the impact load causes stress to be generated at a collision portion P of the cylindrical part 85 in contact with the member 9 and the surroundings, and this stress is transmitted in the plate thickness direction from the collision portion P. Thus, a large amount of stress is generated in a portion 85P on an inner peripheral surface 85B of the cylindrical part 85. The portion 85P is located on the side opposite to the collision portion P in the plate thickness direction.

[0032] As furthermore in Fig. As shown in Figure 3B, when the protruding portion 30 is arranged on the cylindrical part 85, the plate thickness at the position of the protruding portion 30 is greater than at other portions. The protruding portion 30 is formed with a rectangular cross-section. Fig. 3C, the plate thickness at the position where the protruding portion 31 is formed with a trapezoidal cross section is larger than at other portions.

[0033] The protruding portions 30 and 31 both rise in a direction perpendicular to the outer peripheral surface 85A of the cylindrical part 85. Therefore, the rigidity of the cylindrical part 85 in the plate thickness direction changes greatly in the circumferential direction of the cylindrical part 85.

[0034] Assuming that the member 9 of the vehicle collides with the protruding portions 30 and 31, in such a case, the protruding portions 30 and 31, which have higher rigidity than other portions, cause portions P1 where the end edges of each of the protruding portions 30 and 31 are arranged to become high stress concentration areas. Thus, a large amount of stress similar to a case where no protruding portion is formed, as shown in Fig. 13B, is generated on the inner peripheral side (85P) of the portions P1. The portion 85P corresponds to an area where the plate thickness has changed.

[0035] The configurations of Fig. 3B and Fig. 3C cannot reduce the tensile stress acting on the inner peripheral surface 85B of the cylindrical part 85 regardless of an increase in the plate thickness.

[0036] In contrast, in the present embodiment ( Fig. 2) The protruding portion 20 is formed in an arcuate shape. Therefore, even if the plate thickness is partially large, the rigidity in the plate thickness direction gradually changes in the region 203 from the width direction center of the protruding portion 20 (represented by the long-dashed, double-short-dashed line) in the circumferential direction to the end edges 202.

[0037] Therefore, assuming that the vehicle member 9 collides with the arcuate protruding portion 20 in the plate thickness direction, the stress is distributed over the entirety of the regions 203 of the protruding portion 20. The stress distributed in the circumferential direction in the regions 203 results in a reduction in the tensile stress acting on the inner peripheral surface 15B of the cylindrical part 15, including the portions 15P on the back side (inner peripheral surface 15B) of the end edges 202 of the protruding portion 20.

[0038] As explained above, the presence of the protruding portion 20 protruding in an arc-like shape from the outer peripheral surface 15A of the cylindrical part 15 can reduce the stress acting on the cylindrical part 15 at the time of collision, and can ensure that the cylindrical part 15 is strong enough not to be deformed or damaged even at the time of collision.

[0039] The protruding portion 20 may be arranged at least at a portion of the cylindrical part 15 in the circumferential direction. Unlike a case where the plate thickness t is increased over the entire circumference of the cylindrical part 15, thus, the reliability against collision is improved while managing the capacities required for the compressor 1 and the limitations on installation space, weight, etc.

[0040] The protruding portion 20 of the present embodiment extends over the entire length of the cylindrical part 15 in the axial direction, and the rigidity of the protruding portion 20 in the plate thickness direction is approximately uniform in the axial direction of the cylindrical part 15. This allows stress from the collision with the vehicle member 9 to be distributed over the entire longitudinal direction of the protrusion (protruding portion 20) and reduces stress on the portions 15P on the inner peripheral surface 15B located on the rear side of the protrusion.

[0041] As described above, the presence of the arc-like protruding portion 20 reduces the stress acting on the cylindrical portion 15 at the time of a collision to a greater extent than in a case where the protruding portion 20 is not formed.

[0042] Other applicable shapes of the stress reducing protruding portion 20 are described below.

[0043] Fig. 4 obtained by analysis illustrates relationships between a protrusion amount A of the protruding portion 20 and stress ratios with respect to a width B of the protruding portion 20, where (1) indicates a stress ratio when no protruding portion is provided.

[0044] The radius r of the cylindrical part 15 ( Fig. 1B) is set to approximately 60 mm. The radius r of the cylindrical part 15 can also be set to approximately 40 mm to 80 mm, in which case the data is still approximately the same as in Fig. 4 would be the data presented.

[0045] For example, the plate thickness t of the cylindrical part 15 is set to approximately 3.0 mm to 5.0 mm. The plate thickness t can also be set to 2.0 mm to 7.0 mm. In this case, the data would still be approximately the same as in Fig. 4 presented data.

[0046] As in Fig. 2, the protrusion amount A is the height to the tip end 201 (top) of the protruding portion 20 measured in the radial direction of the cylindrical part 15.

[0047] As in Fig. 2, the width B refers to the distance measured from the tip end 201 (top) of the protruding portion 20 to the position of the end edge 202 of the protruding portion 20 in the direction of a tangential line drawn to the tip end 201.

[0048] Here, the end edge 202 refers to a position where a circular arc 20C (long-dashed, single-short-dashed line), which is the basic shape determining the outer shape of the protruding portion 20, intersects a circle 15C, which is the basic shape of the outer peripheral surface 15A of the cylindrical part 15. An R-part 20R, which has a predetermined radius of curvature, is formed at the interface portion between the end edge 202 of the protruding portion 20 and the outer peripheral surface 15A of the cylindrical part 15. In the Fig. According to the data illustrated in Figure 4, the radius of curvature of the R part 20R is approximately 5 mm.

[0049] Under points (1) to (7) in Fig. 4, point (6) is described as an example. When the protrusion circumference A is increased to 5 mm, the stress ratio gradually decreases. Thereafter, when the protrusion amount A of more than 5 mm is given to the protrusion portion 20, the stress ratio begins to increase. The inflection point is indicated by X. The stress ratio is smallest when the protrusion amount A is approximately 5 mm. This is believed to be due to the dispersing effect in that the area 203 of the protrusion portion 20 is largest when the protrusion amount A is approximately 5 mm.

[0050] The above is a tendency seen in all points (1) to (7). In other words, even if the width B is different, the stress reduction effect increases when the protrusion amount A increases up to a certain limit, and when the protrusion amount A exceeds the certain limit, the stress ratio increases.

[0051] Fig. 5 is an approximate curve of data, where each voltage ratio from point (1) to (7) is in Fig. 4 is the smallest. The width B can be expressed by a quadratic curve of the projection amount A.

[0052] Out of Fig. 4 shows that when the protrusion amount is increased, a wider width B can achieve a lower stress ratio, and the stress ratio is low even after the inflection point is exceeded. This is because increasing the width B while fixing the protrusion amount A results in a more gradual change in the rigidity of the region 203 in the circumferential direction than fixing the width B while increasing the protrusion amount A. This indicates that the stress can be better distributed. In other words, the width B has a greater effect on stress reduction than the protrusion amount A. Assuming that the cross-sectional area of ​​the protruding portion 20 is the same, from the perspective of stress reduction, widening the width B is more effective than increasing the protrusion amount A.

[0053] How from the curve in Fig. As can be seen in Figure 4, stress reduction effects are exhibited over a wide range of A and B. Stress reduction effects of up to at least 20% can be achieved for all widths B from (1) to (7) via an appropriate protrusion amount A. Significant stress reduction effects exceeding 40% can be achieved for (5) to (7), compared with a case where the protruding portion is not arranged.

[0054] In the above, a ratio (B / A) of the width B to the protrusion amount A is preferably from 4 to 7, both inclusive. This ratio makes it possible to achieve stress reduction effects of about 20% or more and thus can sufficiently ensure the strength of the cylindrical part 15.

[0055] Although only a portion of the cylindrical part 15 in the circumferential direction is increased in plate thickness by the protruding portion 20, the stress distributing effect by the protruding portion 20 shows similar effects to the case where the plate thickness increases over the entire circumference of the cylindrical part 15.

[0056] The protruding portion 20 does not necessarily have to be an arc-like shape, but may be a substantially arc-like shape similar to an arch.

[0057] A protruding portion 24 having a polygonal shape simulating an arc, as in Fig. 6A illustrates a protruding portion 25 having an elliptical arc-like shape as shown in Fig. 6B illustrates a protruding portion 26 having a long and round shape, as in Fig. 6C, or the like may be applicable. In cases where these protruding portions 24 to 26 are used, it is still possible to obtain data similar to the data described above ( Fig. 4, Fig. 5) regarding stress ratios and set an appropriate protrusion amount A, width B and the like based on the data.

[0058] A buffer element may be provided in the compressor 1 in preparation for a collision.

[0059] Fig. Fig. 7 illustrates a buffer element 4 having a plate shape, which is arranged between the compressor 1 and the element 9 of the vehicle. The buffer element 4 is arranged in an upright position further forward than the compressor 1 in the direction of travel (the arrow) of the vehicle. The buffer element 4 is also preferably connected to the drive circuit unit 14 ( Fig. 1A).

[0060] The provision of the buffer element 4 in addition to the protruding portion 20 can cushion against impact loads exerted in the horizontal direction and the direction intersecting the horizontal direction. Thus, the impact exerted on the compressor 1 is also reduced.

[0061] The protruding portion 20 can be used to support the buffer member 4 on the housing 13 of the compressor 1. In this example, a protrusion 205 is formed integrally with the tip end portion of the protruding portion 20, and the buffer member 4 is fixed to the protrusion 205.

[0062] The plate thickness of the cylindrical part 15 is increased at the position of the protrusion 205, and thus the stress on the cylindrical part 15 at the time of collision is further reduced.

[0063] A second embodiment of the present invention will be described below with reference to Fig. 8A to Fig. 9. Differences from the first embodiment are described below.

[0064] In the second embodiment, the shape of the protruding portion is explained from the viewpoint of the R part.

[0065] Fig. 8A and Fig. 8B shows a protruding portion 22 disposed on the cylindrical part 15 of the second embodiment. The R-part 20R is provided along a predetermined radius of curvature at the interface portion between the end edge 202 of the protruding portion 22 and the outer peripheral surface 15A of the cylindrical portion 15.

[0066] The arc-like R-part 20R seamlessly connects with the circular arc 20C (long dashed, single short dashed line) to define the outer shape of the protruding portion 22 and the circle 15C (dashed line), which is the basic shape of the outer peripheral surface 15A of the cylindrical part 15. The R-part 20R is formed to protrude (inward in the radial direction) toward the inner peripheral side of the cylindrical part 15.

[0067] Fig. Figure 9 illustrates, based on analysis results, relationships between the radius of curvature of the R part 20R and

[0068] stress conditions, while “1” indicates a stress when the protruding portion 20 or the protruding portion 22 is not formed.

[0069] Out of Fig. 9, it can be seen that the stress ratio decreases rapidly as the radius of curvature of the R part 20R gradually increases from about 5 mm.

[0070] The radius of curvature of only the R part 20R is an important factor affecting stress reduction. Regardless of the values ​​of the protrusion amount A and the width B of the arc-shaped protruding portion 20 or the protruding portion 22, the stress is dispersed by providing a suitable R part 20R to sufficiently reduce the stress on the cylindrical part 15.

[0071] Out of Fig. 9 shows that the stress ratio is lower saturated when the radius of curvature exceeds 100 mm.

[0072] In the foregoing, the radius of curvature of the R part 20R is preferably set to, for example, 10 mm or more. The radius of curvature is more preferably 100 mm or more.

[0073] In a third embodiment, the stress reduction effects achieved by the second embodiment are increased to the maximum limits.

[0074] As in Fig. 10, in a protruding portion 23 of the third embodiment, the outline of a cross section orthogonal to the axial line of the cylindrical part 15 runs along two tangential lines L1 and L2.

[0075] The tangential line L1 is drawn to the arc 20C projecting outward in the radial direction of the cylindrical part 15 and to the outer peripheral surface 15A of the cylindrical part 15. The same applies to the tangential line L2.

[0076] The protruding portion 23 of the third embodiment is provided along the arc 20C near an intersection point of the tangential line L1 and the tangential line L2.

[0077] The radius of curvature of the R part 20R of the protruding portion 22 in the second embodiment (8) is increased to infinity, and then the R part 20R is formed substantially linearly along the tangential lines L1 and L2.

[0078] The drawn point 9P, which is in Fig. 9 indicates the stress ratio when the R part 20R is formed substantially according to the tangential lines L1 and L2 connecting the arc 20C of the protruding portion 20 and the outer peripheral surface 15A of the cylindrical part 15.

[0079] The protruding portion 23 of the third embodiment reduces the stress acting on the cylindrical portion 15 in a similar manner as indicated by the plotted point 9P.

[0080] The top of the protruding portion 23 does not necessarily have to be arranged along the arc 20C, but rather may be formed along the circle 15C, which is the basic shape of the outer peripheral surface 15A of the cylindrical part 15, or may be formed flat.

[0081] In the respective embodiments above, a plurality of the protruding portions (20, etc.) may also be formed on the cylindrical part 15 of the housing, as shown in Fig. 11. These protruding portions 20 are arranged with a gap or pitch aligned with each other in the circumferential direction of the cylindrical part 15. These protruding portions 20 all protrude in a direction facing the traveling direction of the vehicle (the white solid arrow) and can disperse stress at the time of a collision to reduce the stress on the cylindrical part 15.

[0082] Next, a fourth embodiment of the present invention will be described with reference to Fig. 12A to Fig. 12C described. Fig. 12A is a side view of a cylindrical member 15 constituting a housing of the electric compressor of the fourth embodiment. A plurality of protruding portions 27 protruding outward in the radial direction are provided on the cylindrical member 15. The plurality of protruding portions 27 are each arranged with a gap or pitch in the axial line direction of the cylindrical member 15. The protruding portions 27 all protrude in the same direction as the traveling direction of the vehicle.

[0083] As in Fig. 12B and Fig. 12C, each of the protruding portions 27 protrudes in a hemispherical shape from the outer peripheral surface 15A of the cylindrical part 15. The “hemispherical shape” may be less than or equal to half a sphere or more than half a sphere. As shown in Fig. 12B, a cross section of the protruding portion 27 along the axial line of the cylindrical part 15 has an arc-like shape that protrudes outward in the radial direction. As shown in Fig. 12C, a cross section of the protruding portion 27 parallel to the axial line of the cylindrical part 15 also has an arc-like shape protruding outward in the radial direction.

[0084] The cross-section of the protruding portion 27 does not necessarily have to be an arc-like shape, but may be a substantially arc-like shape resembling an arc. For example, the cross-section of the protruding portion 27 may have a polygonal shape simulating an arc, as shown in Fig. 6A illustrates an elliptical arc-like shape, as in Fig. 6B illustrates a long and round shape, as in Fig. 6C, or the like. In other words, the protruding portion 27 is not limited to a hemispherical shape and may have a substantially hemispherical shape, including shapes similar to an oval shape, an egg shape, etc.

[0085] The cylindrical part 15 having the plurality of protruding portions 27 is integrally formed by casting or die-casting with a metallic material such as an aluminum alloy.

[0086] The R part may be provided at the interface portion between the end edge 202 of each of the protruding portions 27 and the outer peripheral surface 15A of the cylindrical portion 15.

[0087] The protruding portion 27 is formed in a hemispherical shape, so the rigidity of the cylindrical part 15 in the plate thickness direction gradually changes in all directions from the tip end 201 (top) of the protruding portion 27 to the end edge 202 surrounding the top. For example, the rigidity of the cylindrical part 15 in the plate thickness direction not only gradually changes in the circumferential direction of the cylindrical part 15, which is Fig. 12B, but also in the axial line direction of the cylindrical part 15, which is shown in Fig. 12C. Accordingly, at the time of a collision, the stress is not concentrated on portions between the protruding portions 27 that are adjacent to each other in the axial direction of the cylindrical part 15, but rather the stress can be distributed over the entirety of the protruding portions 27. Therefore, the stress on the cylindrical part 15 is reduced.

[0088] In the example shown in Fig. 12A to 12C, a plurality of the protruding portions 27 are arranged in one row along the axial line direction of the cylindrical part 15, however, the plurality of protruding portions 27 may be located in a plurality of rows along the axial line direction of the cylindrical part 15.

[0089] Alternatively, the plurality of protruding portions 27 may be arranged in a staggered pattern on both sides of a linear line set parallel to the axial line direction on the outer peripheral surface 15A of the cylindrical part 15.

[0090] According to the respective embodiments described above, similar effects to those in the case where the plate thickness is increased over the entire circumference of the cylindrical part 15 can be achieved by forming the arc-like protruding portions 20 and 22, the protruding portion 23 with the outline along the tangential lines L1 and L2, or the hemispherical protruding portions 27, or the like on the cylindrical part 15. Therefore, the strength of the casing 13 of the compressor 1 against collision is ensured while the vehicle is running.

[0091] In addition to electric compressors, the present invention can also be applied to devices to be mounted on vehicles and for which the strength of the housing against a collision is ensured. List of reference symbols 1 electric compressor (a device to be mounted on a vehicle) 4 Buffer element 8 housings 9 Vehicle element 10 Device main body 11 Compression mechanism 12 Engine 13 housings 14 Drive circuit unit 15 Cylindrical part 15A outer peripheral surface 15B inner peripheral surface 15L axial line 15P Section 16 Cover 18 Fastening section 20, 22 to 26 protruding section 20C sheet 20R R- Part 30, 31 protruding section 85 Cylindrical part 85A outer peripheral surface 85B inner peripheral surface 85P Section 140 circuit housings 141 circuit element 142 circuit board 201 top end 202 End edge 203 Area 205 Survey A Advance amount B Width D1 Outwards in radial direction L1, L2 tangent line P Collision section P1 Section

Claims

[1] An electric compressor (1) to be mounted on a vehicle, the electric compressor (1) comprising: a housing (13) for mounting on the vehicle, the housing (13) accommodating a device main body (10) comprising a compression mechanism (11) for compressing a coolant and a motor (12) for outputting a torque for actuating the compression mechanism (11), wherein the housing (13) has a cylindrical part (15) surrounding the device main body (10), wherein a projection (20; 22; 24-26) projecting outward in a radial direction (D1) of the cylindrical part (15) is arranged on the cylindrical part (15), wherein a wall thickness (t) of the cylindrical part (15) is increased at the position of the projection (20; 22; 24-26), and wherein a cross section of the projection (20; 22; 24-26) orthogonal to an axial line (15L) of the cylindrical part (15) has an arc-like shape that projects outward in the radial direction (D1), so that the rigidity in the plate thickness direction changes gradually in the circumferential direction in regions (203) from the width direction center of the projection to end edges, the end edges (202) referring to positions in the circumferential direction at which a circular arc (20C), which is the basic shape that determines the outer shape of the projection (20; 22; 24-26), intersects a circle (15C), which is the basic shape of an outer peripheral surface (15A) of the cylindrical part (15); wherein the projection (20) has a support part (205) configured to support a buffer element (4) on the housing (13) arranged between the electric compressor (1) to be mounted on the vehicle and an element (9) of the vehicle (1); wherein the support part (205) does not protrude beyond the projection (20) in the circumferential direction of the housing (13). [2] The electric compressor (1) according to claim 1, wherein B / A is from 4 to 7, both inclusive, where A is a height to the center of the projection (20; 22; 24-26) measured in the radial direction of the cylindrical part (15), and B is a distance measured from the center of the projection (20; 22; 24-26) to the positions of the end edges (202) of the projection (20; 22; 24-26) in a direction of a tangential line to the center. [3] The electric compressor (1) according to claim 1 or 2, wherein an interface portion between the end edge (202) of the projection (20; 22; 24-26) and an outer surface of the outer peripheral surface (15A) of the cylindrical part (15) has an R part (20R) having an arc-like shape projecting toward an inner peripheral side of the cylindrical part (15). [4] The electric compressor (1) according to claim 3, wherein a radius (r) of the cylindrical part (15) is from 40 mm to 80 mm, both inclusive, and a radius of curvature of the R part (20R) is equal to or greater than 10 mm. [5] An electric compressor (1) to be mounted on a vehicle, the electric compressor (1) comprising: a housing (13) for mounting on the vehicle, the housing (13) accommodating a device main body (10) comprising a compression mechanism (11) for compressing a coolant and a motor (12) for outputting a torque for actuating the compression mechanism (11), wherein the housing (13) has a cylindrical part (15) surrounding the device main body (10), wherein a projection (23) projecting outward in a radial direction (D1) of the cylindrical part (15) is arranged on the cylindrical part (15), wherein a wall thickness (t) of the cylindrical part (15) is increased at the position of the projection (23), and wherein an outline of a cross section of the projection (23) extends orthogonally to an axial line (15L) of the cylindrical part (15) along tangential lines (L1,L2) which are applied in the circumferential direction both to an arc (20C) projecting outward in the radial direction (D1) of the cylindrical part (15) and to an outer peripheral surface (15A) of the cylindrical part (15), the projection (23) extending along the arc (20C) in the vicinity of the intersection point of the tangential lines (L1,L2). wherein the projection (23) has a support part (205) configured to support a buffer element (4) on the housing (13) arranged between the electric compressor (1) to be mounted on the vehicle and an element (9) of the vehicle (1); wherein the support part (205) does not protrude beyond the projection (23) in the circumferential direction of the housing (13). [6] The electric compressor (1) according to any one of claims 1 to 5, wherein the projection (20;22-26) extends along the direction of the axial line (15L) of the cylindrical part (15). [7] An electric compressor (1) to be mounted on a vehicle, the electric compressor (1) comprising: a housing (13) for mounting on the vehicle, the housing (13) accommodating a device main body (10) comprising a compression mechanism (11) for compressing a coolant and a motor (12) for outputting a torque for actuating the compression mechanism (11), wherein the housing (13) has a cylindrical part (15) surrounding the device main body (10), wherein a protruding portion (27) protruding outward in a radial direction (D1) of the cylindrical part (15) is arranged on the cylindrical part (15), wherein a wall thickness (t) of the cylindrical part (15) is increased at the position of the protruding portion (27), and wherein the protruding portion (27) is formed in a hemispherical shape, wherein the protruding portion (27) has a support part (205) configured to support a buffer element (4) on the housing (13) arranged between the electric compressor (1) to be mounted on the vehicle and a member (9) of the vehicle (1); wherein the support part (205) does not protrude beyond protruding sections (27) in the circumferential direction of the housing (13). [8] The electric compressor (1) according to claim 7, wherein a plurality of the protruding portions (27) are arranged in one row or in multiple rows along the direction of an axial line (15L) of the cylindrical part (15). [9] The electric compressor (1) according to any one of claims 1 to 8, wherein the housing (13) is formed integrally with a drive circuit unit (14) configured to drive the motor (12).

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